pub(crate) use crate::{
    ast::{
        self, Annotation, ArgBy, ArgName, AssignmentKind, AssignmentPattern, BinOp, Bls12_381Point,
        ByteArrayFormatPreference, CallArg, Curve, DataType, DataTypeKey, DefinitionLocation,
        Located, LogicalOpChainKind, ParsedCallArg, RecordConstructorArg, RecordUpdateSpread, Span,
        TraceKind, TypedArg, TypedAssignmentKind, TypedClause, TypedDataType, TypedIfBranch,
        TypedPattern, TypedRecordUpdateArg, UnOp, UntypedArg, UntypedAssignmentKind, UntypedClause,
        UntypedIfBranch, UntypedRecordUpdateArg,
    },
    parser::token::Base,
    tipo::{
        ModuleValueConstructor, Type, TypeVar, ValueConstructor, ValueConstructorVariant,
        check_replaceable_opaque_type, convert_opaque_type, lookup_data_type_by_tipo,
    },
};
use indexmap::IndexMap;
use pallas_primitives::alonzo::{Constr, PlutusData};
use std::{fmt::Debug, ops::Deref, rc::Rc};
use uplc::{
    KeyValuePairs,
    ast::Data,
    machine::{runtime::convert_tag_to_constr, value::from_pallas_bigint},
};
use vec1::Vec1;

#[derive(Debug, Clone, PartialEq, serde::Serialize, serde::Deserialize)]
pub enum TypedExpr {
    UInt {
        location: Span,
        tipo: Rc<Type>,
        value: String,
        base: Base,
    },

    String {
        location: Span,
        tipo: Rc<Type>,
        value: String,
    },

    ByteArray {
        location: Span,
        tipo: Rc<Type>,
        bytes: Vec<u8>,
        preferred_format: ByteArrayFormatPreference,
    },

    CurvePoint {
        location: Span,
        tipo: Rc<Type>,
        point: Box<Curve>,
        preferred_format: ByteArrayFormatPreference,
    },

    Sequence {
        location: Span,
        expressions: Vec<Self>,
    },

    /// A chain of pipe expressions.
    /// By this point the type checker has expanded it into a series of
    /// assignments and function calls, but we still have a Pipeline AST node as
    /// even though it is identical to `Sequence` we want to use different
    /// locations when showing it in error messages, etc.
    Pipeline {
        location: Span,
        expressions: Vec<Self>,
    },

    Var {
        location: Span,
        constructor: ValueConstructor,
        name: String,
    },

    Fn {
        location: Span,
        tipo: Rc<Type>,
        is_capture: bool,
        args: Vec<TypedArg>,
        body: Box<Self>,
        return_annotation: Option<Annotation>,
    },

    List {
        location: Span,
        tipo: Rc<Type>,
        elements: Vec<Self>,
        tail: Option<Box<Self>>,
    },

    Call {
        location: Span,
        tipo: Rc<Type>,
        fun: Box<Self>,
        args: Vec<CallArg<Self>>,
    },

    BinOp {
        location: Span,
        tipo: Rc<Type>,
        name: BinOp,
        left: Box<Self>,
        right: Box<Self>,
    },

    Assignment {
        location: Span,
        tipo: Rc<Type>,
        value: Box<Self>,
        pattern: TypedPattern,
        kind: TypedAssignmentKind,
        comment: Option<String>,
    },

    Trace {
        location: Span,
        tipo: Rc<Type>,
        then: Box<Self>,
        text: Box<Self>,
    },

    When {
        location: Span,
        tipo: Rc<Type>,
        subject: Box<Self>,
        clauses: Vec<TypedClause>,
    },

    If {
        location: Span,
        #[serde(with = "Vec1Ref")]
        branches: Vec1<TypedIfBranch>,
        final_else: Box<Self>,
        tipo: Rc<Type>,
    },

    RecordAccess {
        location: Span,
        tipo: Rc<Type>,
        label: String,
        index: u64,
        record: Box<Self>,
    },

    ModuleSelect {
        location: Span,
        tipo: Rc<Type>,
        label: String,
        module_name: String,
        module_alias: String,
        constructor: ModuleValueConstructor,
    },

    Tuple {
        location: Span,
        tipo: Rc<Type>,
        elems: Vec<Self>,
    },

    Pair {
        location: Span,
        tipo: Rc<Type>,
        fst: Box<Self>,
        snd: Box<Self>,
    },

    TupleIndex {
        location: Span,
        tipo: Rc<Type>,
        index: usize,
        tuple: Box<Self>,
    },

    ErrorTerm {
        location: Span,
        tipo: Rc<Type>,
    },

    RecordUpdate {
        location: Span,
        tipo: Rc<Type>,
        spread: Box<Self>,
        args: Vec<TypedRecordUpdateArg>,
    },

    UnOp {
        location: Span,
        value: Box<Self>,
        tipo: Rc<Type>,
        op: UnOp,
    },
}

#[derive(serde::Serialize, serde::Deserialize)]
#[serde(remote = "Vec1")]
struct Vec1Ref<T>(#[serde(getter = "Vec1::as_vec")] Vec<T>);

impl<T> From<Vec1Ref<T>> for Vec1<T> {
    fn from(v: Vec1Ref<T>) -> Self {
        Vec1::try_from_vec(v.0).unwrap()
    }
}

impl TypedExpr {
    pub fn is_simple_expr_to_format(&self) -> bool {
        match self {
            Self::String { .. } | Self::UInt { .. } | Self::ByteArray { .. } | Self::Var { .. } => {
                true
            }
            Self::Pair { fst, snd, .. } => {
                fst.is_simple_expr_to_format() && snd.is_simple_expr_to_format()
            }
            Self::Tuple { elems, .. } => elems.iter().all(|e| e.is_simple_expr_to_format()),
            Self::List { elements, .. } if elements.len() <= 3 => {
                elements.iter().all(|e| e.is_simple_expr_to_format())
            }
            Self::UnOp { value, .. } => value.is_simple_expr_to_format(),
            _ => false,
        }
    }

    pub fn and_then(self, next: Self) -> Self {
        if let TypedExpr::Trace {
            tipo,
            location,
            then,
            text,
        } = self
        {
            return TypedExpr::Trace {
                tipo,
                location,
                then: Box::new(then.and_then(next)),
                text,
            };
        }

        TypedExpr::Sequence {
            location: self.location(),
            expressions: vec![self, next],
        }
    }

    pub fn sequence(exprs: &[TypedExpr]) -> Self {
        TypedExpr::Sequence {
            location: Span::empty(),
            expressions: exprs.to_vec(),
        }
    }

    pub fn let_(value: Self, pattern: TypedPattern, tipo: Rc<Type>, location: Span) -> Self {
        TypedExpr::Assignment {
            tipo: tipo.clone(),
            value: value.into(),
            pattern,
            kind: AssignmentKind::let_(),
            comment: None,
            location,
        }
    }

    // Create an expect assignment, unless the target type is `Data`; then fallback to a let.
    pub fn flexible_expect(
        value: Self,
        pattern: TypedPattern,
        tipo: Rc<Type>,
        location: Span,
    ) -> Self {
        TypedExpr::Assignment {
            tipo: tipo.clone(),
            value: value.into(),
            pattern,
            kind: if tipo.is_data() {
                AssignmentKind::let_()
            } else {
                AssignmentKind::expect()
            },
            comment: None,
            location,
        }
    }

    pub fn local_var(name: &str, tipo: Rc<Type>, location: Span) -> Self {
        TypedExpr::Var {
            constructor: ValueConstructor {
                public: true,
                variant: ValueConstructorVariant::LocalVariable {
                    location: Span::empty(),
                },
                tipo: tipo.clone(),
            },
            name: name.to_string(),
            location,
        }
    }

    pub fn tipo(&self) -> Rc<Type> {
        match self {
            Self::Var { constructor, .. } => constructor.tipo.clone(),
            Self::Trace { then, .. } => then.tipo(),
            Self::Fn { tipo, .. }
            | Self::UInt { tipo, .. }
            | Self::ErrorTerm { tipo, .. }
            | Self::When { tipo, .. }
            | Self::List { tipo, .. }
            | Self::Call { tipo, .. }
            | Self::If { tipo, .. }
            | Self::UnOp { tipo, .. }
            | Self::BinOp { tipo, .. }
            | Self::Tuple { tipo, .. }
            | Self::Pair { tipo, .. }
            | Self::String { tipo, .. }
            | Self::ByteArray { tipo, .. }
            | Self::TupleIndex { tipo, .. }
            | Self::Assignment { tipo, .. }
            | Self::ModuleSelect { tipo, .. }
            | Self::RecordAccess { tipo, .. }
            | Self::RecordUpdate { tipo, .. }
            | Self::CurvePoint { tipo, .. } => tipo.clone(),
            Self::Pipeline { expressions, .. } | Self::Sequence { expressions, .. } => expressions
                .last()
                .map(TypedExpr::tipo)
                .unwrap_or_else(Type::void),
        }
    }

    pub fn replace_type(&mut self, new_type: Rc<Type>) {
        match self {
            Self::Var { constructor, .. } => {
                constructor.tipo = new_type;
            }
            Self::Trace { then, .. } => then.replace_type(new_type),
            Self::Fn { tipo, .. }
            | Self::UInt { tipo, .. }
            | Self::ErrorTerm { tipo, .. }
            | Self::When { tipo, .. }
            | Self::List { tipo, .. }
            | Self::Call { tipo, .. }
            | Self::If { tipo, .. }
            | Self::UnOp { tipo, .. }
            | Self::BinOp { tipo, .. }
            | Self::Tuple { tipo, .. }
            | Self::Pair { tipo, .. }
            | Self::String { tipo, .. }
            | Self::ByteArray { tipo, .. }
            | Self::TupleIndex { tipo, .. }
            | Self::Assignment { tipo, .. }
            | Self::ModuleSelect { tipo, .. }
            | Self::RecordAccess { tipo, .. }
            | Self::RecordUpdate { tipo, .. }
            | Self::CurvePoint { tipo, .. } => *tipo = new_type,
            Self::Pipeline { expressions, .. } | Self::Sequence { expressions, .. } => {
                expressions
                    .last_mut()
                    .expect("trying to replace type of an empty sequence or pipeline")
                    .replace_type(new_type);
            }
        }
    }

    pub fn is_literal(&self) -> bool {
        matches!(
            self,
            Self::UInt { .. }
                | Self::List { .. }
                | Self::Tuple { .. }
                | Self::String { .. }
                | Self::ByteArray { .. }
        )
    }

    pub fn is_error_term(&self) -> bool {
        matches!(self, Self::ErrorTerm { .. })
    }

    /// Returns `true` if the typed expr is [`Assignment`].
    pub fn is_assignment(&self) -> bool {
        matches!(self, Self::Assignment { .. })
    }

    pub fn definition_location(&self) -> Option<DefinitionLocation<'_>> {
        match self {
            TypedExpr::Fn { .. }
            | TypedExpr::UInt { .. }
            | TypedExpr::Trace { .. }
            | TypedExpr::List { .. }
            | TypedExpr::Call { .. }
            | TypedExpr::When { .. }
            | TypedExpr::ErrorTerm { .. }
            | TypedExpr::BinOp { .. }
            | TypedExpr::Tuple { .. }
            | TypedExpr::Pair { .. }
            | TypedExpr::UnOp { .. }
            | TypedExpr::String { .. }
            | TypedExpr::Sequence { .. }
            | TypedExpr::Pipeline { .. }
            | TypedExpr::ByteArray { .. }
            | TypedExpr::Assignment { .. }
            | TypedExpr::TupleIndex { .. }
            | TypedExpr::RecordAccess { .. }
            | TypedExpr::CurvePoint { .. } => None,
            TypedExpr::If { .. } => None,

            // TODO: test
            // TODO: definition
            TypedExpr::RecordUpdate { .. } => None,

            // TODO: test
            TypedExpr::ModuleSelect {
                module_name,
                constructor,
                ..
            } => Some(DefinitionLocation {
                module: Some(module_name.as_str()),
                span: constructor.location(),
            }),

            // TODO: test
            TypedExpr::Var { constructor, .. } => Some(constructor.definition_location()),
        }
    }

    pub fn type_defining_location(&self) -> Span {
        match self {
            Self::Fn { location, .. }
            | Self::UInt { location, .. }
            | Self::Var { location, .. }
            | Self::Trace { location, .. }
            | Self::ErrorTerm { location, .. }
            | Self::When { location, .. }
            | Self::Call { location, .. }
            | Self::List { location, .. }
            | Self::BinOp { location, .. }
            | Self::Tuple { location, .. }
            | Self::Pair { location, .. }
            | Self::String { location, .. }
            | Self::UnOp { location, .. }
            | Self::Pipeline { location, .. }
            | Self::ByteArray { location, .. }
            | Self::Assignment { location, .. }
            | Self::TupleIndex { location, .. }
            | Self::ModuleSelect { location, .. }
            | Self::RecordAccess { location, .. }
            | Self::RecordUpdate { location, .. }
            | Self::CurvePoint { location, .. } => *location,

            Self::If { branches, .. } => branches.first().body.type_defining_location(),

            Self::Sequence {
                expressions,
                location,
                ..
            } => expressions
                .last()
                .map(TypedExpr::location)
                .unwrap_or(*location),
        }
    }

    pub fn location(&self) -> Span {
        match self {
            Self::Fn { location, .. }
            | Self::UInt { location, .. }
            | Self::Trace { location, .. }
            | Self::Var { location, .. }
            | Self::ErrorTerm { location, .. }
            | Self::When { location, .. }
            | Self::Call { location, .. }
            | Self::If { location, .. }
            | Self::List { location, .. }
            | Self::BinOp { location, .. }
            | Self::Tuple { location, .. }
            | Self::Pair { location, .. }
            | Self::String { location, .. }
            | Self::UnOp { location, .. }
            | Self::Sequence { location, .. }
            | Self::Pipeline { location, .. }
            | Self::ByteArray { location, .. }
            | Self::Assignment { location, .. }
            | Self::TupleIndex { location, .. }
            | Self::ModuleSelect { location, .. }
            | Self::RecordAccess { location, .. }
            | Self::RecordUpdate { location, .. }
            | Self::CurvePoint { location, .. } => *location,
        }
    }

    // This could be optimised in places to exit early if the first of a series
    // of expressions is after the byte index.
    pub fn find_node(&self, byte_index: usize) -> Option<Located<'_>> {
        if !self.location().contains(byte_index) {
            return None;
        }

        match self {
            TypedExpr::ErrorTerm { .. }
            | TypedExpr::Var { .. }
            | TypedExpr::UInt { .. }
            | TypedExpr::String { .. }
            | TypedExpr::ByteArray { .. }
            | TypedExpr::ModuleSelect { .. }
            | TypedExpr::CurvePoint { .. } => Some(Located::Expression(self)),

            TypedExpr::Trace { text, then, .. } => text
                .find_node(byte_index)
                .or_else(|| then.find_node(byte_index))
                .or(Some(Located::Expression(self))),

            TypedExpr::Pipeline { expressions, .. } | TypedExpr::Sequence { expressions, .. } => {
                expressions.iter().find_map(|e| e.find_node(byte_index))
            }

            TypedExpr::Fn {
                body,
                args,
                return_annotation,
                ..
            } => args
                .iter()
                .find_map(|arg| arg.find_node(byte_index))
                .or_else(|| body.find_node(byte_index))
                .or_else(|| {
                    return_annotation
                        .as_ref()
                        .and_then(|a| a.find_node(byte_index))
                })
                .or(Some(Located::Expression(self))),

            TypedExpr::Tuple {
                elems: elements, ..
            } => elements
                .iter()
                .find_map(|e| e.find_node(byte_index))
                .or(Some(Located::Expression(self))),

            TypedExpr::Pair { fst, snd, .. } => [fst, snd]
                .iter()
                .find_map(|e| e.find_node(byte_index))
                .or(Some(Located::Expression(self))),

            TypedExpr::List { elements, tail, .. } => elements
                .iter()
                .find_map(|e| e.find_node(byte_index))
                .or_else(|| tail.as_ref().and_then(|t| t.find_node(byte_index)))
                .or(Some(Located::Expression(self))),

            TypedExpr::Call { fun, args, .. } => args
                .iter()
                .find_map(|arg| arg.find_node(byte_index))
                .or_else(|| fun.find_node(byte_index))
                .or(Some(Located::Expression(self))),

            TypedExpr::BinOp { left, right, .. } => left
                .find_node(byte_index)
                .or_else(|| right.find_node(byte_index))
                .or(Some(Located::Expression(self))),

            TypedExpr::Assignment { value, pattern, .. } => pattern
                .find_node(byte_index, &value.tipo())
                .or_else(|| value.find_node(byte_index)),

            TypedExpr::When {
                subject, clauses, ..
            } => subject
                .find_node(byte_index)
                .or_else(|| {
                    clauses
                        .iter()
                        .find_map(|clause| clause.find_node(byte_index, &subject.tipo()))
                })
                .or(Some(Located::Expression(self))),

            TypedExpr::RecordAccess {
                record: expression, ..
            }
            | TypedExpr::TupleIndex {
                tuple: expression, ..
            } => expression
                .find_node(byte_index)
                .or(Some(Located::Expression(self))),

            TypedExpr::RecordUpdate { spread, args, .. } => args
                .iter()
                .find_map(|arg| arg.find_node(byte_index))
                .or_else(|| spread.find_node(byte_index))
                .or(Some(Located::Expression(self))),

            TypedExpr::If {
                branches,
                final_else,
                ..
            } => branches
                .iter()
                .find_map(|branch| {
                    branch
                        .condition
                        .find_node(byte_index)
                        .or_else(|| branch.body.find_node(byte_index))
                })
                .or_else(|| final_else.find_node(byte_index))
                .or(Some(Located::Expression(self))),

            TypedExpr::UnOp { value, .. } => value
                .find_node(byte_index)
                .or(Some(Located::Expression(self))),
        }
    }

    pub fn void(location: Span) -> Self {
        TypedExpr::Var {
            name: "Void".to_string(),
            constructor: ValueConstructor {
                public: true,
                variant: ValueConstructorVariant::Record {
                    name: "Void".to_string(),
                    arity: 0,
                    field_map: None,
                    location: Span::empty(),
                    module: String::new(),
                    constructors_count: 1,
                },
                tipo: Type::void(),
            },
            location,
        }
    }
}

// Represent how a function was written so that we can format it back.
#[derive(Debug, Clone, PartialEq, Copy)]
pub enum FnStyle {
    Plain,
    Capture,
    BinOp(BinOp),
}

#[derive(Debug, Clone, PartialEq)]
pub enum UntypedExpr {
    UInt {
        location: Span,
        value: String,
        base: Base,
    },

    String {
        location: Span,
        value: String,
    },

    Sequence {
        location: Span,
        expressions: Vec<Self>,
    },

    Var {
        location: Span,
        name: String,
    },

    Fn {
        location: Span,
        fn_style: FnStyle,
        arguments: Vec<UntypedArg>,
        body: Box<Self>,
        return_annotation: Option<Annotation>,
    },

    List {
        location: Span,
        elements: Vec<Self>,
        tail: Option<Box<Self>>,
    },

    Call {
        arguments: Vec<CallArg<Self>>,
        fun: Box<Self>,
        location: Span,
    },

    BinOp {
        location: Span,
        name: BinOp,
        left: Box<Self>,
        right: Box<Self>,
    },

    ByteArray {
        location: Span,
        bytes: Vec<(u8, Span)>,
        preferred_format: ByteArrayFormatPreference,
    },

    CurvePoint {
        location: Span,
        point: Box<Curve>,
        preferred_format: ByteArrayFormatPreference,
    },

    PipeLine {
        expressions: Vec1<Self>,
        one_liner: bool,
    },

    Assignment {
        location: Span,
        value: Box<Self>,
        patterns: Vec1<AssignmentPattern>,
        kind: UntypedAssignmentKind,
        comment: Option<String>,
    },

    Trace {
        kind: TraceKind,
        location: Span,
        then: Box<Self>,
        label: Box<Self>,
        arguments: Vec<Self>,
    },

    TraceIfFalse {
        location: Span,
        value: Box<Self>,
    },

    When {
        location: Span,
        subject: Box<Self>,
        clauses: Vec<UntypedClause>,
    },

    If {
        location: Span,
        branches: Vec1<UntypedIfBranch>,
        final_else: Box<Self>,
    },

    FieldAccess {
        location: Span,
        label: String,
        container: Box<Self>,
    },

    Tuple {
        location: Span,
        elems: Vec<Self>,
    },

    Pair {
        location: Span,
        fst: Box<Self>,
        snd: Box<Self>,
    },

    TupleIndex {
        location: Span,
        index: usize,
        tuple: Box<Self>,
    },

    ErrorTerm {
        location: Span,
    },

    RecordUpdate {
        location: Span,
        constructor: Box<Self>,
        spread: RecordUpdateSpread,
        arguments: Vec<UntypedRecordUpdateArg>,
    },

    UnOp {
        op: UnOp,
        location: Span,
        value: Box<Self>,
    },

    LogicalOpChain {
        kind: LogicalOpChainKind,
        expressions: Vec<Self>,
        location: Span,
    },
}

pub const DEFAULT_TODO_STR: &str = "aiken::todo";

pub const DEFAULT_ERROR_STR: &str = "aiken::error";

impl UntypedExpr {
    // Reify some opaque 'Constant' into an 'UntypedExpr', using a Type annotation. We also need
    // an extra map to lookup record & enum constructor's names as they're completely erased when
    // in their PlutusData form, and the Type annotation only contains type name.
    //
    // The function performs some sanity check to ensure that the type does indeed somewhat
    // correspond to the data being given.
    pub fn reify_constant(
        data_types: &IndexMap<&DataTypeKey, &TypedDataType>,
        cst: uplc::ast::Constant,
        tipo: Rc<Type>,
    ) -> Result<Self, String> {
        UntypedExpr::do_reify_constant(data_types, cst, tipo)
    }

    pub fn is_discard(&self) -> bool {
        matches!(self, UntypedExpr::Var { name, ..} if name.starts_with("_"))
    }

    // Reify some opaque 'PlutusData' into an 'UntypedExpr', using a Type annotation. We also need
    // an extra map to lookup record & enum constructor's names as they're completely erased when
    // in their PlutusData form, and the Type annotation only contains type name.
    //
    // The function performs some sanity check to ensure that the type does indeed somewhat
    // correspond to the data being given.
    pub fn reify_data(
        data_types: &IndexMap<&DataTypeKey, &TypedDataType>,
        data: PlutusData,
        tipo: Rc<Type>,
    ) -> Result<Self, String> {
        UntypedExpr::do_reify_data(data_types, data, tipo)
    }

    fn reify_with<T, F>(
        data_types: &IndexMap<&DataTypeKey, &TypedDataType>,
        t: T,
        tipo: Rc<Type>,
        with: F,
    ) -> Result<Self, String>
    where
        T: Debug,
        F: Fn(&IndexMap<&DataTypeKey, &TypedDataType>, T, Rc<Type>) -> Result<Self, String>,
    {
        if let Type::Var { tipo: var_tipo, .. } = tipo.deref() {
            match &*var_tipo.borrow() {
                TypeVar::Link { tipo } => {
                    return Self::reify_with(data_types, t, tipo.clone(), with);
                }
                _ => unreachable!("unbound type during reification {tipo:?} -> {t:?}"),
            }
        }

        // NOTE: Opaque types are tricky. We can't tell from a type only if it is
        // opaque or not. We have to lookup its datatype definition.
        //
        // Also, we can't -- in theory -- peak into an opaque type. More so, if it
        // has a single constructor with a single argument, it is an zero-cost
        // wrapper. That means the underlying PlutusData has no residue of that
        // wrapper. So we have to manually reconstruct it before crawling further
        // down the type tree.
        if check_replaceable_opaque_type(&tipo, data_types) {
            let DataType { name, .. } = lookup_data_type_by_tipo(data_types, &tipo)
                .expect("Type just disappeared from known types? {tipo:?}");

            let inner_type = convert_opaque_type(&tipo, data_types, false);

            let value = Self::reify_with(data_types, t, inner_type, with)?;

            return Ok(UntypedExpr::Call {
                location: Span::empty(),
                arguments: vec![CallArg {
                    label: None,
                    location: Span::empty(),
                    value,
                }],
                fun: Box::new(UntypedExpr::Var {
                    name,
                    location: Span::empty(),
                }),
            });
        }

        with(data_types, t, tipo)
    }

    fn do_reify_constant(
        data_types: &IndexMap<&DataTypeKey, &TypedDataType>,
        cst: uplc::ast::Constant,
        tipo: Rc<Type>,
    ) -> Result<Self, String> {
        Self::reify_with(data_types, cst, tipo, |data_types, cst, tipo| match cst {
            uplc::ast::Constant::Data(data) => UntypedExpr::do_reify_data(data_types, data, tipo),

            uplc::ast::Constant::Integer(i) => {
                UntypedExpr::do_reify_data(data_types, Data::integer(i), tipo)
            }

            uplc::ast::Constant::ByteString(bytes) => {
                UntypedExpr::do_reify_data(data_types, Data::bytestring(bytes), tipo)
            }

            uplc::ast::Constant::ProtoList(_, args) => match tipo.deref() {
                Type::App {
                    module,
                    name,
                    args: type_args,
                    ..
                } if module.is_empty() && name.as_str() == "List" => {
                    if let [inner] = &type_args[..] {
                        Ok(UntypedExpr::List {
                            location: Span::empty(),
                            elements: args
                                .into_iter()
                                .map(|arg| {
                                    UntypedExpr::do_reify_constant(data_types, arg, inner.clone())
                                })
                                .collect::<Result<Vec<_>, _>>()?,
                            tail: None,
                        })
                    } else {
                        Err(
                            "invalid List type annotation: the list has multiple type-parameters."
                                .to_string(),
                        )
                    }
                }
                Type::Tuple { elems, .. } => Ok(UntypedExpr::Tuple {
                    location: Span::empty(),
                    elems: args
                        .into_iter()
                        .zip(elems)
                        .map(|(arg, arg_type)| {
                            UntypedExpr::do_reify_constant(data_types, arg, arg_type.clone())
                        })
                        .collect::<Result<Vec<_>, _>>()?,
                }),
                _ => Err(format!(
                    "invalid type annotation. expected List but got: {tipo:?}"
                )),
            },

            uplc::ast::Constant::ProtoPair(_, _, left, right) => match tipo.deref() {
                Type::Pair { fst, snd, .. } => {
                    let elems = [left.as_ref(), right.as_ref()]
                        .into_iter()
                        .zip([fst, snd])
                        .map(|(arg, arg_type)| {
                            UntypedExpr::do_reify_constant(
                                data_types,
                                arg.to_owned(),
                                arg_type.clone(),
                            )
                        })
                        .collect::<Result<Vec<_>, _>>()?;

                    Ok(UntypedExpr::Pair {
                        location: Span::empty(),
                        fst: elems.first().unwrap().to_owned().into(),
                        snd: elems.last().unwrap().to_owned().into(),
                    })
                }
                _ => Err(format!(
                    "invalid type annotation. expected Pair but got: {tipo:?}"
                )),
            },

            uplc::ast::Constant::Unit => Ok(UntypedExpr::Var {
                location: Span::empty(),
                name: "Void".to_string(),
            }),

            uplc::ast::Constant::Bool(is_true) => Ok(UntypedExpr::Var {
                location: Span::empty(),
                name: if is_true { "True" } else { "False" }.to_string(),
            }),

            uplc::ast::Constant::String(value) => Ok(UntypedExpr::String {
                location: Span::empty(),
                value,
            }),

            uplc::ast::Constant::Bls12_381G1Element(pt) => Ok(UntypedExpr::CurvePoint {
                location: Span::empty(),
                point: Curve::Bls12_381(Bls12_381Point::G1(*pt)).into(),
                preferred_format: ByteArrayFormatPreference::HexadecimalString,
            }),

            uplc::ast::Constant::Bls12_381G2Element(pt) => Ok(UntypedExpr::CurvePoint {
                location: Span::empty(),
                point: Curve::Bls12_381(Bls12_381Point::G2(*pt)).into(),
                preferred_format: ByteArrayFormatPreference::HexadecimalString,
            }),

            uplc::ast::Constant::Bls12_381MlResult(ml) => {
                let mut bytes = Vec::new();

                bytes.extend((*ml).to_bendian());

                // NOTE: We don't actually have a syntax for representing MillerLoop results, so we
                // just fake it as a constructor with a bytearray. Note also that the bytearray is
                // *large*.
                Ok(UntypedExpr::Call {
                    location: Span::empty(),
                    arguments: vec![CallArg {
                        label: None,
                        location: Span::empty(),
                        value: UntypedExpr::ByteArray {
                            location: Span::empty(),
                            bytes: bytes.into_iter().map(|b| (b, Span::empty())).collect(),
                            preferred_format: ByteArrayFormatPreference::HexadecimalString,
                        },
                    }],
                    fun: Box::new(UntypedExpr::Var {
                        name: "MillerLoopResult".to_string(),
                        location: Span::empty(),
                    }),
                })
            }
        })
    }

    fn reify_blind(data: PlutusData) -> Self {
        match data {
            PlutusData::BigInt(ref i) => UntypedExpr::UInt {
                location: Span::empty(),
                base: Base::Decimal {
                    numeric_underscore: false,
                },
                value: from_pallas_bigint(i).to_string(),
            },

            PlutusData::BoundedBytes(bytes) => {
                let bytes: Vec<u8> = bytes.into();

                UntypedExpr::ByteArray {
                    location: Span::empty(),
                    bytes: bytes.into_iter().map(|b| (b, Span::empty())).collect(),
                    preferred_format: ByteArrayFormatPreference::HexadecimalString,
                }
            }

            PlutusData::Array(elems) => UntypedExpr::List {
                location: Span::empty(),
                elements: elems
                    .to_vec()
                    .into_iter()
                    .map(UntypedExpr::reify_blind)
                    .collect::<Vec<_>>(),
                tail: None,
            },

            PlutusData::Map(indef_or_def) => {
                let kvs = match indef_or_def {
                    KeyValuePairs::Def(kvs) => kvs,
                    KeyValuePairs::Indef(kvs) => kvs,
                };

                UntypedExpr::List {
                    location: Span::empty(),
                    elements: kvs
                        .into_iter()
                        .map(|(k, v)| UntypedExpr::Pair {
                            location: Span::empty(),
                            fst: UntypedExpr::reify_blind(k).into(),
                            snd: UntypedExpr::reify_blind(v).into(),
                        })
                        .collect::<Vec<_>>(),
                    tail: None,
                }
            }

            PlutusData::Constr(Constr {
                tag,
                any_constructor,
                fields,
            }) => {
                let ix = convert_tag_to_constr(tag).or(any_constructor).unwrap() as usize;

                let fields = fields
                    .to_vec()
                    .into_iter()
                    .map(|field| CallArg {
                        location: Span::empty(),
                        label: None,
                        value: UntypedExpr::reify_blind(field),
                    })
                    .collect::<Vec<_>>();

                let mut arguments = vec![CallArg {
                    location: Span::empty(),
                    label: None,
                    value: UntypedExpr::UInt {
                        location: Span::empty(),
                        value: ix.to_string(),
                        base: Base::Decimal {
                            numeric_underscore: false,
                        },
                    },
                }];
                arguments.extend(fields);

                UntypedExpr::Call {
                    location: Span::empty(),
                    arguments,
                    fun: UntypedExpr::Var {
                        name: "Constr".to_string(),
                        location: Span::empty(),
                    }
                    .into(),
                }
            }
        }
    }

    fn do_reify_data(
        data_types: &IndexMap<&DataTypeKey, &TypedDataType>,
        data: PlutusData,
        tipo: Rc<Type>,
    ) -> Result<Self, String> {
        let tipo = Type::collapse_links(tipo);

        if let Type::App { name, module, .. } = tipo.deref()
            && module.is_empty()
            && name == "Data"
        {
            return Ok(Self::reify_blind(data));
        }

        Self::reify_with(
            data_types,
            data,
            tipo,
            |data_types, data, tipo| match data {
                PlutusData::BigInt(ref i) => Ok(UntypedExpr::UInt {
                    location: Span::empty(),
                    base: Base::Decimal {
                        numeric_underscore: false,
                    },
                    value: from_pallas_bigint(i).to_string(),
                }),

                PlutusData::BoundedBytes(bytes) => {
                    if tipo.is_string() {
                        Ok(UntypedExpr::String {
                            location: Span::empty(),
                            value: String::from_utf8(bytes.to_vec()).expect("invalid UTF-8 string"),
                        })
                    } else {
                        let bytes: Vec<u8> = bytes.into();
                        Ok(UntypedExpr::ByteArray {
                            location: Span::empty(),
                            bytes: bytes.into_iter().map(|b| (b, Span::empty())).collect(),
                            preferred_format: ByteArrayFormatPreference::HexadecimalString,
                        })
                    }
                }

                PlutusData::Array(args) => match tipo.deref() {
                    Type::App {
                        module,
                        name,
                        args: type_args,
                        ..
                    } if module.is_empty() && name.as_str() == "List" => {
                        if let [inner] = &type_args[..] {
                            Ok(UntypedExpr::List {
                                location: Span::empty(),
                                elements: args
                                    .to_vec()
                                    .into_iter()
                                    .map(|arg| {
                                        UntypedExpr::do_reify_data(data_types, arg, inner.clone())
                                    })
                                    .collect::<Result<Vec<_>, _>>()?,
                                tail: None,
                            })
                        } else {
                            Err(
                                "invalid List type annotation: the list has multiple type-parameters."
                                    .to_string(),
                            )
                        }
                    }
                    Type::Tuple { elems, .. } => Ok(UntypedExpr::Tuple {
                        location: Span::empty(),
                        elems: args
                            .to_vec()
                            .into_iter()
                            .zip(elems)
                            .map(|(arg, arg_type)| {
                                UntypedExpr::do_reify_data(data_types, arg, arg_type.clone())
                            })
                            .collect::<Result<Vec<_>, _>>()?,
                    }),
                    Type::Pair { fst, snd, .. } => {
                        let mut elems = args
                            .to_vec()
                            .into_iter()
                            .zip([fst, snd])
                            .map(|(arg, arg_type)| {
                                UntypedExpr::do_reify_data(data_types, arg, arg_type.clone())
                            })
                            .collect::<Result<Vec<_>, _>>()?;

                        Ok(UntypedExpr::Pair {
                            location: Span::empty(),
                            fst: elems.remove(0).into(),
                            snd: elems.remove(0).into(),
                        })
                    }
                    _ => Err(format!(
                        "invalid type annotation. expected List but got: {tipo:?}"
                    )),
                },

                PlutusData::Constr(Constr {
                    tag,
                    any_constructor,
                    fields,
                }) => {
                    let ix = convert_tag_to_constr(tag).or(any_constructor).unwrap() as usize;

                    if let Type::App { args, .. } = tipo.deref()
                        && let Some(DataType {
                            constructors,
                            typed_parameters,
                            ..
                        }) = lookup_data_type_by_tipo(data_types, &tipo)
                    {
                        if constructors.is_empty() {
                            return Ok(UntypedExpr::Var {
                                location: Span::empty(),
                                name: "Data".to_string(),
                            });
                        }

                        let constructor = &constructors[ix];

                        let generics = typed_parameters.iter().zip(args).fold(
                            IndexMap::new(),
                            |mut generics, (generic, arg)| {
                                if let Some(ix) = generic.get_generic_id() {
                                    generics.insert(ix, arg.clone());
                                }

                                generics
                            },
                        );

                        return if fields.is_empty() {
                            Ok(UntypedExpr::Var {
                                location: Span::empty(),
                                name: constructor.name.to_string(),
                            })
                        } else {
                            let arguments = fields
                                .to_vec()
                                .into_iter()
                                .zip(constructor.arguments.iter())
                                .map(|(field, RecordConstructorArg { label, tipo, .. })| {
                                    let mut tipo = tipo;

                                    // Replace any generic with their specialised definitions
                                    // for this type instance.
                                    if let Type::Var { tipo: var, .. } =
                                        Type::collapse_links(tipo.clone()).as_ref()
                                        && let TypeVar::Generic { id } = &*var.borrow()
                                    {
                                        tipo = generics.get(id).expect("unknown generic?");
                                    }

                                    UntypedExpr::do_reify_data(data_types, field, tipo.clone()).map(
                                        |value| CallArg {
                                            label: label.clone(),
                                            location: Span::empty(),
                                            value,
                                        },
                                    )
                                })
                                .collect::<Result<Vec<_>, _>>()?;

                            Ok(UntypedExpr::Call {
                                location: Span::empty(),
                                arguments,
                                fun: Box::new(UntypedExpr::Var {
                                    name: constructor.name.to_string(),
                                    location: Span::empty(),
                                }),
                            })
                        };
                    }

                    Err(format!(
                        "invalid type annotation {tipo:?} for {}{} constructor with fields: {fields:?}",
                        ix + 1,
                        ordinal::Ordinal::<usize>(ix + 1).suffix(),
                    ))
                }

                PlutusData::Map(indef_or_def) => {
                    let kvs = match indef_or_def {
                        KeyValuePairs::Def(kvs) => kvs,
                        KeyValuePairs::Indef(kvs) => kvs,
                    };

                    UntypedExpr::do_reify_data(
                        data_types,
                        Data::list(
                            kvs.into_iter()
                                .map(|(k, v)| Data::list(vec![k, v]))
                                .collect(),
                        ),
                        tipo,
                    )
                }
            },
        )
    }

    pub fn todo(reason: Option<Self>, location: Span) -> Self {
        UntypedExpr::Trace {
            location,
            kind: TraceKind::Todo,
            then: Box::new(UntypedExpr::ErrorTerm { location }),
            label: Box::new(reason.unwrap_or_else(|| UntypedExpr::String {
                location,
                value: DEFAULT_TODO_STR.to_string(),
            })),
            arguments: Vec::new(),
        }
    }

    pub fn fail(reason: Option<Self>, location: Span) -> Self {
        if let Some(reason) = reason {
            UntypedExpr::Trace {
                location,
                kind: TraceKind::Error,
                then: Box::new(UntypedExpr::ErrorTerm { location }),
                label: Box::new(reason),
                arguments: Vec::new(),
            }
        } else {
            UntypedExpr::ErrorTerm { location }
        }
    }

    pub fn tuple_index(self, index: usize, location: Span) -> Self {
        UntypedExpr::TupleIndex {
            location: self.location().union(location),
            index,
            tuple: Box::new(self),
        }
    }

    pub fn field_access(self, label: String, location: Span) -> Self {
        UntypedExpr::FieldAccess {
            location: self.location().union(location),
            label,
            container: Box::new(self),
        }
    }

    pub fn call(self, args: Vec<ParsedCallArg>, location: Span) -> Self {
        let mut holes = Vec::new();

        let args = args
            .into_iter()
            .enumerate()
            .map(|(index, a)| match a {
                CallArg {
                    value: Some(value),
                    label,
                    location,
                } if !value.is_discard() => CallArg {
                    value,
                    label,
                    location,
                },
                CallArg {
                    value,
                    label,
                    location,
                } => {
                    let name = format!(
                        "{}__{index}_{}",
                        ast::CAPTURE_VARIABLE,
                        match value {
                            Some(UntypedExpr::Var { ref name, .. }) => name,
                            _ => "_",
                        }
                    );

                    holes.push(ast::UntypedArg {
                        location: Span::empty(),
                        annotation: None,
                        doc: None,
                        by: ArgBy::ByName(ast::ArgName::Named {
                            label: name.clone(),
                            name: name.clone(),
                            location: Span::empty(),
                        }),
                        is_validator_param: false,
                    });

                    ast::CallArg {
                        label,
                        location,
                        value: UntypedExpr::Var { location, name },
                    }
                }
            })
            .collect();

        let call = UntypedExpr::Call {
            location: self.location().union(location),
            fun: Box::new(self),
            arguments: args,
        };

        if holes.is_empty() {
            call
        } else {
            UntypedExpr::Fn {
                location: call.location(),
                fn_style: FnStyle::Capture,
                arguments: holes,
                body: Box::new(call),
                return_annotation: None,
            }
        }
    }

    pub fn append_in_sequence(self, next: Self) -> Self {
        let location = Span {
            start: self.location().start,
            end: next.location().end,
        };

        match (self.clone(), next.clone()) {
            (left @ Self::Sequence { .. }, right @ Self::Sequence { .. }) => Self::Sequence {
                location,
                expressions: vec![left, right],
            },
            (
                _,
                Self::Sequence {
                    expressions: mut next_expressions,
                    ..
                },
            ) => {
                let mut current_expressions = vec![self];

                current_expressions.append(&mut next_expressions);

                Self::Sequence {
                    location,
                    expressions: current_expressions,
                }
            }

            (_, _) => Self::Sequence {
                location,
                expressions: vec![self, next],
            },
        }
    }

    pub fn location(&self) -> Span {
        match self {
            Self::PipeLine { expressions, .. } => expressions.last().location(),
            Self::Trace { then, .. } => then.location(),
            Self::TraceIfFalse { location, .. }
            | Self::Fn { location, .. }
            | Self::Var { location, .. }
            | Self::UInt { location, .. }
            | Self::ErrorTerm { location, .. }
            | Self::When { location, .. }
            | Self::Call { location, .. }
            | Self::List { location, .. }
            | Self::ByteArray { location, .. }
            | Self::BinOp { location, .. }
            | Self::Tuple { location, .. }
            | Self::Pair { location, .. }
            | Self::String { location, .. }
            | Self::Assignment { location, .. }
            | Self::TupleIndex { location, .. }
            | Self::FieldAccess { location, .. }
            | Self::RecordUpdate { location, .. }
            | Self::UnOp { location, .. }
            | Self::LogicalOpChain { location, .. }
            | Self::If { location, .. }
            | Self::CurvePoint { location, .. } => *location,
            Self::Sequence {
                location,
                expressions,
                ..
            } => expressions.last().map(Self::location).unwrap_or(*location),
        }
    }

    pub fn start_byte_index(&self) -> usize {
        match self {
            Self::Sequence {
                expressions,
                location,
                ..
            } => expressions
                .first()
                .map(|e| e.start_byte_index())
                .unwrap_or(location.start),
            Self::PipeLine { expressions, .. } => expressions.first().start_byte_index(),
            Self::Trace { location, .. } | Self::Assignment { location, .. } => location.start,
            _ => self.location().start,
        }
    }

    pub fn binop_precedence(&self) -> u8 {
        match self {
            Self::BinOp { name, .. } => name.precedence(),
            Self::PipeLine { .. } => 0,
            _ => u8::MAX,
        }
    }

    /// Returns true when an UntypedExpr can be displayed in a flex-break manner (i.e. tries to fit as
    /// much as possible on a single line). When false, long lines with several of those patterns
    /// will be broken down to one expr per line.
    pub fn is_simple_expr_to_format(&self) -> bool {
        match self {
            Self::String { .. } | Self::UInt { .. } | Self::ByteArray { .. } | Self::Var { .. } => {
                true
            }
            Self::Pair { fst, snd, .. } => {
                fst.is_simple_expr_to_format() && snd.is_simple_expr_to_format()
            }
            Self::Tuple { elems, .. } => elems.iter().all(|e| e.is_simple_expr_to_format()),
            Self::List { elements, .. } if elements.len() <= 3 => {
                elements.iter().all(|e| e.is_simple_expr_to_format())
            }
            _ => false,
        }
    }

    pub fn lambda(
        names: Vec<(ArgName, Span, Option<Annotation>)>,
        expressions: Vec<UntypedExpr>,
        location: Span,
    ) -> Self {
        Self::Fn {
            location,
            fn_style: FnStyle::Plain,
            arguments: names
                .into_iter()
                .map(|(arg_name, location, annotation)| UntypedArg {
                    location,
                    doc: None,
                    annotation,
                    is_validator_param: false,
                    by: ArgBy::ByName(arg_name),
                })
                .collect(),
            body: Self::Sequence {
                location,
                expressions,
            }
            .into(),
            return_annotation: None,
        }
    }
}
