#![deny(rust_2018_idioms)]

use crate::rust_ir::*;
use chalk_ir::interner::Interner;

use chalk_ir::*;
use std::fmt::Debug;
use std::sync::Arc;

#[cfg(test)]
#[macro_use]
mod test_macros;

pub mod clauses;
pub mod coherence;
mod coinductive_goal;
pub mod ext;
pub mod goal_builder;
mod infer;
#[cfg(feature = "recursive-solver")]
pub mod recursive;
pub mod rust_ir;
mod solve;
pub mod split;
pub mod wf;

pub trait RustIrDatabase<I: Interner>: Debug {
    /// Returns any "custom program clauses" that do not derive from
    /// Rust IR. Used only in testing the underlying solver.
    fn custom_clauses(&self) -> Vec<ProgramClause<I>>;

    /// Returns the datum for the associated type with the given id.
    fn associated_ty_data(&self, ty: AssocTypeId<I>) -> Arc<AssociatedTyDatum<I>>;

    /// Returns the datum for the definition with the given id.
    fn trait_datum(&self, trait_id: TraitId<I>) -> Arc<TraitDatum<I>>;

    /// Returns the datum for the impl with the given id.
    fn adt_datum(&self, adt_id: AdtId<I>) -> Arc<AdtDatum<I>>;

    fn fn_def_datum(&self, fn_def_id: FnDefId<I>) -> Arc<FnDefDatum<I>>;

    /// Returns the datum for the impl with the given id.
    fn impl_datum(&self, impl_id: ImplId<I>) -> Arc<ImplDatum<I>>;

    /// Returns the `AssociatedTyValue` with the given id.
    fn associated_ty_value(&self, id: AssociatedTyValueId<I>) -> Arc<AssociatedTyValue<I>>;

    /// Returns the `OpaqueTyDatum` with the given id.
    fn opaque_ty_data(&self, id: OpaqueTyId<I>) -> Arc<OpaqueTyDatum<I>>;

    /// Returns the "hidden type" corresponding with the opaque type.
    fn hidden_opaque_type(&self, id: OpaqueTyId<I>) -> Ty<I>;

    /// Returns a list of potentially relevant impls for a given
    /// trait-id; we also supply the type parameters that we are
    /// trying to match (if known: these parameters may contain
    /// inference variables, for example). The implementor is
    /// permitted to return any superset of the applicable impls;
    /// chalk will narrow down the list to only those that truly
    /// apply. The parameters are provided as a "hint" to help the
    /// implementor do less work, but can be completely ignored if
    /// desired.
    fn impls_for_trait(&self, trait_id: TraitId<I>, parameters: &[GenericArg<I>])
        -> Vec<ImplId<I>>;

    /// Returns the impls that require coherence checking. This is not the
    /// full set of impls that exist:
    ///
    /// - It can exclude impls not defined in the current crate.
    /// - It can exclude "built-in" impls, like those for closures; only the
    ///   impls actually written by users need to be checked.
    fn local_impls_to_coherence_check(&self, trait_id: TraitId<I>) -> Vec<ImplId<I>>;

    /// Returns true if there is an explicit impl of the auto trait
    /// `auto_trait_id` for the ADT `adt_id`. This is part of
    /// the auto trait handling -- if there is no explicit impl given
    /// by the user for the struct, then we provide default impls
    /// based on the field types (otherwise, we rely on the impls the
    /// user gave).
    fn impl_provided_for(&self, auto_trait_id: TraitId<I>, adt_id: AdtId<I>) -> bool;

    /// A stop-gap solution to force an impl for a given well-known trait.
    /// Useful when the logic for a given trait is absent or incomplete.
    /// A value of `Some(true)` means that the the clause for the impl will be
    /// added. A value of `Some(false)` means that the clause for the impl will
    /// not be added, and fallback logic will not be checked. A value of `None`
    /// means that the clause will not be added, but fallback logic may add logic.
    #[allow(unused_variables)]
    fn force_impl_for(&self, well_known: WellKnownTrait, ty: &TyData<I>) -> Option<bool> {
        None
    }

    /// Returns id of a trait lang item, if found
    fn well_known_trait_id(&self, well_known_trait: WellKnownTrait) -> Option<TraitId<I>>;

    /// Calculates program clauses from an env. This is intended to call the
    /// `program_clauses_for_env` function and then possibly cache the clauses.
    fn program_clauses_for_env(&self, environment: &Environment<I>) -> ProgramClauses<I>;

    fn interner(&self) -> &I;

    /// Check if a trait is object safe
    fn is_object_safe(&self, trait_id: TraitId<I>) -> bool;

    /// Gets the `ClosureKind` for a given closure and substitution.
    fn closure_kind(&self, closure_id: ClosureId<I>, substs: &Substitution<I>) -> ClosureKind;

    /// Gets the inputs and output for a given closure id and substitution. We
    /// pass both the `ClosureId` and it's `Substituion` to give implementors
    /// the freedom to store associated data in the substitution (like rustc) or
    /// separately (like chalk-integration).
    fn closure_inputs_and_output(
        &self,
        closure_id: ClosureId<I>,
        substs: &Substitution<I>,
    ) -> Binders<FnDefInputsAndOutputDatum<I>>;

    /// Gets the upvars as a `Ty` for a given closure id and substitution. There
    /// are no restrictions on the type of upvars.
    fn closure_upvars(&self, closure_id: ClosureId<I>, substs: &Substitution<I>) -> Binders<Ty<I>>;

    /// Gets the substitution for the closure when used as a function.
    /// For example, for the following (not-quite-)rust code:
    /// ```ignore
    /// let foo = |a: &mut u32| { a += 1; };
    /// let c: &'a u32 = &0;
    /// foo(c);
    /// ```
    ///
    /// This would return a `Substitution` of `[&'a]`. This could either be
    /// substituted into the inputs and output, or into the upvars.
    fn closure_fn_substitution(
        &self,
        closure_id: ClosureId<I>,
        substs: &Substitution<I>,
    ) -> Substitution<I>;
}

pub use clauses::program_clauses_for_env;

pub use solve::Guidance;
pub use solve::Solution;
pub use solve::Solver;
pub use solve::SolverChoice;
pub use solve::SubstitutionResult;

#[macro_use]
mod debug_macros {
    #[macro_export]
    macro_rules! debug_span {
        ($($t: tt)*) => {
            let __span = tracing::debug_span!($($t)*);
            let __span = __span.enter();
        };
    }
}