//! Per-expression resolved symbol data, retained from Pass 2.
//!
//! The static analyzer already resolves types for every expression during
//! analysis but historically discarded the intermediate state.  This module
//! exposes that data so that downstream consumers (e.g. php-lsp) can build
//! position indexes for hover, go-to-definition, and completions.

use std::sync::Arc;

use mir_types::Union;
use php_ast::Span;

/// A single resolved symbol observed during Pass 2.
#[derive(Debug, Clone)]
pub struct ResolvedSymbol {
    /// Absolute path of the file this symbol was found in.
    pub file: Arc<str>,
    /// Byte-offset span in the source file.
    pub span: Span,
    /// What kind of symbol this is.
    pub kind: SymbolKind,
    /// The resolved type at this location.
    pub resolved_type: Union,
}

impl ResolvedSymbol {
    /// Return the key used in `Codebase::symbol_reference_locations` for this
    /// symbol, or `None` for kinds that are not tracked there (e.g. variables).
    ///
    /// Key format mirrors `mark_*_referenced_at`:
    /// - method / static call : `"ClassName::methodname"` (method lowercased)
    /// - property access      : `"ClassName::propName"`
    /// - function call        : fully-qualified function name
    /// - class reference      : fully-qualified class name
    pub fn codebase_key(&self) -> Option<String> {
        match &self.kind {
            SymbolKind::MethodCall { class, method } | SymbolKind::StaticCall { class, method } => {
                Some(format!("{}::{}", class, method.to_lowercase()))
            }
            SymbolKind::PropertyAccess { class, property } => {
                Some(format!("{}::{}", class, property))
            }
            SymbolKind::FunctionCall(fqn) => Some(fqn.to_string()),
            SymbolKind::ClassReference(fqcn) => Some(fqcn.to_string()),
            SymbolKind::Variable(_) => None,
        }
    }
}

/// The kind of symbol that was resolved.
#[derive(Debug, Clone)]
pub enum SymbolKind {
    /// A variable reference (`$foo`).
    Variable(String),
    /// An instance method call (`$obj->method()`).
    MethodCall { class: Arc<str>, method: Arc<str> },
    /// A static method call (`Foo::method()`).
    StaticCall { class: Arc<str>, method: Arc<str> },
    /// A property access (`$obj->prop`).
    PropertyAccess { class: Arc<str>, property: Arc<str> },
    /// A free function call (`foo()`).
    FunctionCall(Arc<str>),
    /// A class reference (`new Foo`, `instanceof Foo`, type hints).
    ClassReference(Arc<str>),
}
