use std::collections::HashMap;

use super::typedef::{SharedUnifier, Type};
use crossbeam::queue::SegQueue;
use crossbeam::sync::ShardedLock;
use rustpython_parser::ast::Stmt;

pub struct DefinitionId(usize);

pub enum TopLevelDef {
    Class {
        // object ID used for TypeEnum
        object_id: usize,
        // type variables bounded to the class.
        type_vars: Vec<Type>,
        // class fields and method signature.
        fields: Vec<(String, Type)>,
        // class methods, pointing to the corresponding function definition.
        methods: Vec<(String, DefinitionId)>,
        // ancestor classes, including itself.
        ancestors: Vec<DefinitionId>,
    },
    Function {
        signature: Type,
        /// Function instance to symbol mapping
        /// Key: string representation of type variable values, sorted by variable ID in ascending
        /// order, including type variables associated with the class.
        /// Value: function symbol name.
        instance_to_symbol: HashMap<String, String>,
        /// Function instances to annotated AST mapping
        /// Key: string representation of type variable values, sorted by variable ID in ascending
        /// order, including type variables associated with the class. Excluding rigid type
        /// variables.
        /// Value: AST annotated with types together with a unification table index. Could contain
        /// rigid type variables that would be substituted when the function is instantiated.
        instance_to_stmt: HashMap<String, (Stmt<Type>, usize)>,
    },
}

pub struct CodeGenTask {
    pub subst: HashMap<usize, Type>,
    pub symbol_name: String,
    pub body: Stmt<Type>,
    pub unifier: SharedUnifier,
}

pub struct TopLevelContext {
    pub definitions: Vec<ShardedLock<TopLevelDef>>,
    pub unifiers: Vec<SharedUnifier>,
    pub codegen_queue: SegQueue<CodeGenTask>,
}