package build

import (
	"fmt"

	"git.akyoto.dev/cli/q/src/build/expression"
	"git.akyoto.dev/cli/q/src/build/token"
	"git.akyoto.dev/cli/q/src/errors"
)

// CompileKeyword compiles an instruction that starts with a keyword.
func (f *Function) CompileKeyword(line token.List) error {
	switch line[0].Text() {
	case "return":
		if len(line) > 1 {
			value := expression.Parse(line[1:])
			defer value.Close()
			// TODO: Set the return value
		}

		f.Assembler.Return()

	case "loop":
		blockStart := line.IndexKind(token.BlockStart) + 1
		blockEnd := line.LastIndexKind(token.BlockEnd)

		if blockStart == -1 {
			return errors.New(errors.MissingBlockStart, f.File, line[0].End())
		}

		if blockEnd == -1 {
			return errors.New(errors.MissingBlockEnd, f.File, line[len(line)-1].End())
		}

		loop := fmt.Sprintf("%s_loop_%d", f.Name, f.count.loop)
		f.Assembler.Label(loop)
		defer f.Assembler.Jump(loop)
		f.count.loop++
		return f.CompileTokens(line[blockStart:blockEnd])

	default:
		return errors.New(&errors.KeywordNotImplemented{Keyword: line[0].Text()}, f.File, line[0].Position)
	}

	return nil
}