use crate::ast::fqn_context::FqnContext;
use crate::ast::helpers::{collect_diagnostics_into_mut, collect_parameter_symbols_into};
use crate::ast::parameter::Parameter;
use crate::ast::type_use::TypeUse;
use crate::diagnostic::Diagnostic;
use crate::source_range::SourceRange;
use crate::symbol::Symbol;
use crate::symbol::function_symbol::FunctionSymbol;
use crate::symbol_table::SymbolTable;
use crate::types_table::TypesTable;
use crate::{diagnostics_result, handle_diagnostics};
use std::rc::Rc;

pub struct ExternFunction {
    declared_name: Rc<str>,
    declared_name_source_range: SourceRange,
    parameters: Vec<Parameter>,
    return_type: TypeUse,
    scope_id: Option<usize>,
}

impl ExternFunction {
    pub fn new(
        name: &str,
        declared_name_source_range: SourceRange,
        parameters: Vec<Parameter>,
        return_type: TypeUse,
    ) -> Self {
        Self {
            declared_name: name.into(),
            declared_name_source_range,
            parameters,
            return_type,
            scope_id: None,
        }
    }

    pub fn declared_name(&self) -> &str {
        &self.declared_name
    }

    pub fn init_scopes(&mut self, symbol_table: &mut SymbolTable, container_scope: usize) {
        self.scope_id = Some(container_scope);

        symbol_table.push_function_scope(&format!("extern_function_scope({})", self.declared_name));

        for parameter in &mut self.parameters {
            parameter.init_scopes(symbol_table, container_scope);
        }
        self.return_type.init_scopes(symbol_table, container_scope);

        symbol_table.pop_scope();
    }

    pub fn make_symbols(&self, fqn_context: &FqnContext) -> (Rc<FunctionSymbol>, Vec<Symbol>) {
        let mut all_symbols: Vec<Symbol> = Vec::new();

        let mut parameter_symbols = Vec::new();
        collect_parameter_symbols_into(&self.parameters, &mut all_symbols, &mut parameter_symbols);

        let function_symbol = Rc::new(FunctionSymbol::new(
            &self.declared_name,
            self.declared_name_source_range.clone(),
            fqn_context.resolve(self.declared_name()),
            true,
            false,
            self.scope_id.unwrap(),
            parameter_symbols,
        ));
        all_symbols.push(Symbol::Function(function_symbol.clone()));

        (function_symbol, all_symbols)
    }

    pub fn check_names(&self, symbol_table: &SymbolTable) -> Vec<Diagnostic> {
        let mut diagnostics: Vec<Diagnostic> = Vec::new();
        for parameter in &self.parameters {
            diagnostics.append(&mut parameter.check_names(symbol_table));
        }
        diagnostics.append(&mut self.return_type.check_names(symbol_table));
        diagnostics
    }

    pub fn gather_types(&self, symbol_table: &SymbolTable, types_table: &mut TypesTable) {
        let function_symbol = symbol_table
            .get_function_symbol_owned(self.scope_id.unwrap(), self.declared_name())
            .unwrap();
        let resolved_return_type = self
            .return_type
            .type_info(symbol_table, types_table)
            .clone();
        types_table
            .function_return_types_mut()
            .insert(function_symbol, resolved_return_type);
    }

    fn type_check_parameters(
        &mut self,
        symbol_table: &SymbolTable,
        types_table: &TypesTable,
        diagnostics: &mut Vec<Diagnostic>,
    ) {
        collect_diagnostics_into_mut(
            &mut self.parameters,
            |p| p.type_check(symbol_table, types_table),
            diagnostics,
        );
    }

    fn type_check_return_type(
        &mut self,
        symbol_table: &SymbolTable,
        types_table: &TypesTable,
        diagnostics: &mut Vec<Diagnostic>,
    ) {
        handle_diagnostics!(
            self.return_type.type_check(symbol_table, types_table),
            diagnostics
        );
    }

    pub fn type_check(
        &mut self,
        symbol_table: &SymbolTable,
        types_table: &TypesTable,
    ) -> Result<(), Vec<Diagnostic>> {
        let mut diagnostics: Vec<Diagnostic> = vec![];

        self.type_check_parameters(symbol_table, types_table, &mut diagnostics);
        self.type_check_return_type(symbol_table, types_table, &mut diagnostics);

        diagnostics_result!(diagnostics)
    }
}