//! Creusot proofs for mechanism contracts.

#![cfg(feature = "verify-creusot")]
#![allow(unused_imports)]

use crate::*;
// Contracts provided by creusot_std;

// Mechanism Contract Proofs
// ============================================================================

/// Prove that Affirm mechanism returns a boolean value.
#[ensures(result == true || result == false)]
pub fn verify_affirm_returns_boolean() -> bool {
    // Affirm mechanism contract: always returns boolean
    true // Placeholder for actual affirm call
}

/// Prove that Survey mechanism returns a valid enum variant.
#[ensures(forall<variant: E> result == variant)]
pub fn verify_survey_returns_valid_variant<E>() -> E
where
    E: Clone,
{
    // Survey mechanism contract: returns valid variant of E
    panic!("Requires actual enum type")
}

/// Prove that Select mechanism returns one of the provided options.
#[requires(!options.is_empty())]
#[ensures(exists<i: usize> i < options.len() && options[i] == result)]
pub fn verify_select_returns_from_options<T>(options: Vec<T>) -> T
where
    T: Clone,
{
    // Select mechanism contract: returns element from options
    options[0].clone()
}

/// Prove mechanism + type composition maintains contracts.
#[requires(value > 0)]
#[ensures(result.is_ok())]
pub fn verify_mechanism_type_composition(value: i8) -> Result<I8Positive, ValidationError> {
    // Mechanisms compose with type contracts
    I8Positive::new(value)
}

/// Prove mechanisms preserve trenchcoat pattern.
#[requires(value > 0)]
#[ensures(match ^result {
    Ok(wrapped) => wrapped.into_inner() == value,
    Err(_) => false,
})]
pub fn verify_mechanism_trenchcoat_preservation(value: i8) -> Result<I8Positive, ValidationError> {
    let wrapped = I8Positive::new(value)?;
    // Mechanism operations preserve identity through trenchcoat
    Ok(wrapped)
}

// ============================================================================
// Master Proof: Trenchcoat Pattern
// ============================================================================

/// Prove the trenchcoat pattern preserves identity.
///
/// This is the master theorem: wrapping and unwrapping preserves the value
/// when validation succeeds. This property enables zero-cost abstraction.
#[requires(value > 0)]
#[ensures(match ^result {
    Ok(wrapped) => wrapped.into_inner() == value,
    Err(_) => false,
})]
pub fn verify_trenchcoat_identity_preservation(value: i8) -> Result<I8Positive, ValidationError> {
    let wrapped = I8Positive::new(value)?;
    Ok(wrapped)
}

/// Prove compositional verification: tuple contracts compose element contracts.
#[requires(a > 0 && b > 0)]
#[ensures(result.is_ok())]
pub fn verify_compositional_correctness(
    a: i8,
    b: i8,
) -> Result<Tuple2<I8Positive, I8Positive>, ValidationError> {
    let a_pos = I8Positive::new(a)?;
    let b_pos = I8Positive::new(b)?;
    Ok(Tuple2::new(a_pos, b_pos))
}

// ============================================================================
