use crate::ast::expression::Expression;
use crate::ast::ir_builder::IrBuilder;
use crate::diagnostic::Diagnostic;
use crate::ir::ir_assign::IrAssign;
use crate::ir::ir_expression::IrExpression;
use crate::ir::ir_multiply::IrMultiply;
use crate::ir::ir_operation::IrOperation;
use crate::ir::ir_statement::IrStatement;
use crate::ir::ir_variable::IrVariable;
use crate::source_range::SourceRange;
use crate::symbol_table::SymbolTable;
use crate::type_info::TypeInfo;
use std::cell::RefCell;
use std::rc::Rc;

pub struct NegativeExpression {
    operand: Box<Expression>,
    source_range: SourceRange,
    type_info: Option<TypeInfo>,
}

impl NegativeExpression {
    pub fn new(operand: Expression, source_range: SourceRange) -> Self {
        Self {
            operand: operand.into(),
            source_range,
            type_info: None,
        }
    }

    pub fn source_range(&self) -> &SourceRange {
        &self.source_range
    }

    pub fn operand(&self) -> &Expression {
        &self.operand
    }

    pub fn operand_mut(&mut self) -> &mut Expression {
        &mut self.operand
    }

    pub fn gather_declared_names(
        &mut self,
        symbol_table: &mut SymbolTable,
    ) -> Result<(), Vec<Diagnostic>> {
        self.operand.gather_declared_names(symbol_table)
    }

    pub fn check_name_usages(&mut self, symbol_table: &SymbolTable) -> Result<(), Vec<Diagnostic>> {
        self.operand.check_name_usages(symbol_table)
    }

    pub fn type_check(&mut self, symbol_table: &SymbolTable) -> Result<(), Vec<Diagnostic>> {
        self.operand.type_check(symbol_table)?;

        let type_info = self.operand.type_info();
        if type_info.can_negate() {
            self.type_info = Some(type_info.negate_result());
            Ok(())
        } else {
            Err(vec![Diagnostic::new(
                &format!("Cannot negate {}", type_info),
                self.source_range.start(),
                self.source_range.end(),
            )])
        }
    }

    pub fn to_ir(&self, builder: &mut IrBuilder, symbol_table: &SymbolTable) -> IrExpression {
        let operand_as_ir = self
            .operand
            .to_ir_expression(builder, symbol_table)
            .expect("Attempt to negate non-value expression");

        match operand_as_ir {
            IrExpression::Parameter(parameter) => {
                let destination = Rc::new(RefCell::new(IrVariable::new_vr(
                    builder.new_t_var().into(),
                    builder.current_block().id(),
                    parameter.type_info(),
                )));

                let rhs = match parameter.type_info() {
                    TypeInfo::Integer => IrExpression::Int(-1),
                    TypeInfo::Double => IrExpression::Double(-1.0),
                    _ => panic!("Trying to multiply with a non-integer/double"),
                };

                let operation =
                    IrOperation::Multiply(IrMultiply::new(IrExpression::Parameter(parameter), rhs));

                let assign = IrAssign::new(destination.clone(), operation);
                builder
                    .current_block_mut()
                    .add_statement(IrStatement::Assign(assign));

                IrExpression::Variable(destination)
            }
            IrExpression::Variable(variable) => {
                let destination = Rc::new(RefCell::new(IrVariable::new_vr(
                    builder.new_t_var().into(),
                    builder.current_block().id(),
                    variable.borrow().type_info(),
                )));

                let rhs = match variable.borrow().type_info() {
                    TypeInfo::Integer => IrExpression::Int(-1),
                    TypeInfo::Double => IrExpression::Double(-1.0),
                    _ => panic!("Trying to multiply with a non-integer/double"),
                };

                let operation =
                    IrOperation::Multiply(IrMultiply::new(IrExpression::Variable(variable), rhs));

                let assign = IrAssign::new(destination.clone(), operation);
                builder
                    .current_block_mut()
                    .add_statement(IrStatement::Assign(assign));

                IrExpression::Variable(destination)
            }
            IrExpression::Int(i) => IrExpression::Int(i * -1),
            IrExpression::Double(d) => IrExpression::Double(d * -1.0),
            IrExpression::String(_) => {
                panic!("Attempt to negate IrExpression::String")
            }
        }
    }

    pub fn type_info(&self) -> &TypeInfo {
        self.type_info.as_ref().unwrap()
    }
}