package commands

import (
	"fmt"
	"strings"

	"c65gm/internal/compiler"
	"c65gm/internal/preproc"
	"c65gm/internal/utils"
)

// OriginCommand handles ORIGIN declarations
// Syntax: ORIGIN <address>
// Sets the assembly origin address (ACME: *= address)
type OriginCommand struct {
	address uint16
}

func (c *OriginCommand) WillHandle(line preproc.Line) bool {
	params, err := utils.ParseParams(line.Text)
	if err != nil || len(params) == 0 {
		return false
	}
	upper := strings.ToUpper(params[0])
	return upper == "ORIGIN" || upper == "ORGIN" // Support common typo
}

func (c *OriginCommand) Interpret(line preproc.Line, ctx *compiler.CompilerContext) error {
	params, err := utils.ParseParams(line.Text)
	if err != nil {
		return err
	}

	if len(params) != 2 {
		return fmt.Errorf("ORIGIN: expected 2 parameters, got %d", len(params))
	}

	scope := ctx.CurrentScope()
	constLookup := func(name string) (int64, bool) {
		sym := ctx.SymbolTable.Lookup(name, scope)
		if sym != nil && sym.IsConst() {
			return int64(sym.Value), true
		}
		return 0, false
	}

	val, err := utils.EvaluateExpression(params[1], constLookup)
	if err != nil {
		return fmt.Errorf("ORIGIN: invalid address expression: %w", err)
	}

	if val < 0 || val > 65535 {
		return fmt.Errorf("ORIGIN: address %d out of range (0-65535)", val)
	}

	c.address = uint16(val)
	return nil
}

func (c *OriginCommand) Generate(_ *compiler.CompilerContext) ([]string, error) {
	return []string{fmt.Sprintf("*= $%04x", c.address)}, nil
}