package core

import (
	"fmt"
	"math"

	"git.urbach.dev/cli/q/src/asm"
	"git.urbach.dev/cli/q/src/ast"
	"git.urbach.dev/cli/q/src/errors"
	"git.urbach.dev/cli/q/src/eval"
	"git.urbach.dev/cli/q/src/types"
)

// CompileAssignArray compiles an assign statement for array elements.
func (f *Function) CompileAssignArray(node *ast.Assign) error {
	left := node.Expression.Children[0]
	right := node.Expression.Children[1]
	name := left.Children[0].Token.Text(f.File.Bytes)
	variable := f.VariableByName(name)

	if variable == nil {
		return errors.New(&errors.UnknownIdentifier{Name: name}, f.File, left.Children[0].Token.Position)
	}

	defer f.UseVariable(variable)

	memory := asm.Memory{
		Base:           variable.Register,
		Offset:         0,
		OffsetRegister: math.MaxUint8,
		Length:         byte(1),
	}

	indexExpr := left.Children[1]
	index, err := f.Evaluate(indexExpr)

	if err != nil {
		return err
	}

	if !types.Is(index.Type, types.AnyInt) {
		return errors.New(&errors.TypeMismatch{Encountered: index.Type.Name(), Expected: types.AnyInt.Name()}, f.File, indexExpr.Token.Position)
	}

	switch index.Kind {
	case eval.Number:
		memory.Offset = int8(index.Number)
	case eval.Register:
		memory.OffsetRegister = index.Register
		defer f.FreeRegister(index.Register)
	default:
		panic(fmt.Errorf("%s: not implemented: %d", f.UniqueName, index.Kind))
	}

	_, err = f.ExpressionToMemory(right, memory)
	return err
}