package main

import (
	"fmt"
	"os"
	"path/filepath"
	"strings"
	"strconv"

	"github.com/alexflint/go-arg"

	"git.zorchenhimer.com/zorchenhimer/go-fds"
)

type Arguments struct {
	Input string `arg:"positional,required"`

	// for getting a specific file
	Side int `arg:"--side" default:"-1"`

	FileNum int `arg:"--file-num" default:"-1"`
	Range string `arg:"--range"`
}

func main() {
	args := &Arguments{}
	arg.MustParse(args)

	err := run(args)
	if err != nil {
		fmt.Fprintln(os.Stderr, err)
		os.Exit(1)
	}
}

func run(args *Arguments) error {
	rom, err := fds.ReadRomFile(args.Input)
	if err != nil {
		return err
	}

	outdir := strings.TrimSuffix(args.Input, filepath.Ext(args.Input))
	err = os.MkdirAll(outdir, 0775)
	if err != nil {
		return err
	}

	if args.Side >= 0 && args.FileNum == -1 {
		if args.Side >= len(rom.Sides) {
			return fmt.Errorf("--side out of range")
		}

		num := 0
		for _, s := range rom.Sides[:args.Side] {
			num += len(s.Files)
		}

		side := rom.Sides[args.Side]
		sideName := fmt.Sprintf("Side%d", side.Header.PhysicalSide)
		for _, file := range side.Files {
			fileName := filepath.Join(outdir, fmt.Sprintf("%03d_%s_%02d_%02X", num, sideName, file.Number, file.Id))
			err := os.WriteFile(fileName, file.Data, 0664)
			if err != nil {
				return err
			}
			num++
		}
		return nil
	} else if args.Side >= 0 && args.FileNum >= 0 {
		if args.Side >= len(rom.Sides) {
			return fmt.Errorf("--side out of range")
		}

		side := rom.Sides[args.Side]

		if len(side.Files) <= args.FileNum {
			return fmt.Errorf("--file-num out of range; %d", len(side.Files))
		}

		sideName := fmt.Sprintf("Side%d", side.Header.PhysicalSide)
		file := side.Files[args.FileNum]

		var start int
		var end int
		if args.Range != "" {
			start, end, err = parseRange(args.Range)
			if err != nil {
				return err
			}

			fmt.Printf("start: %04X\nend: %04X\n", start, end)

			start = start - int(file.Address)
			end = end - int(file.Address)

			fmt.Printf("start: %04X\nend: %04X\n", start, end)

		} else {
			start = 0
			end = file.Size
		}

		fileName := filepath.Join(outdir, fmt.Sprintf("%03d_%s_%02d_%02X", args.FileNum, sideName, file.Number, file.Id))
		fmt.Println("fileName:", fileName)
		err := os.WriteFile(fileName, file.Data[start:end], 0664)
		if err != nil {
			return err
		}
		return nil

	} else if args.Range != "" && (args.Side < 0 || args.FileNum < 0) {
		return fmt.Errorf("--range cannot be given alone")
	}

	num := 0
	for _, side := range rom.Sides {
		sideName := fmt.Sprintf("Side%d", side.Header.PhysicalSide)
		for _, file := range side.Files {
			fileName := filepath.Join(outdir, fmt.Sprintf("%03d_%s_%02d_%02X", args.FileNum, sideName, file.Number, file.Id))
			err := os.WriteFile(fileName, file.Data, 0664)
			if err != nil {
				return err
			}
			num++
		}
	}

	return nil
}

// $6000-$5000
func parseRange(input string) (int, int, error) {
	splits := strings.Split(input, "-")
	if len(splits) != 2 {
		return 0, 0, fmt.Errorf("invalid range: %q", input)
	}
	fmt.Println("splits:", splits)

	splits[0] = strings.Replace(splits[0], "$", "0x", 1)
	splits[1] = strings.Replace(splits[1], "$", "0x", 1)

	fmt.Println("splits:", splits)

	start, err := strconv.ParseInt(splits[0], 0, 64)
	if err != nil {
		return 0, 0, fmt.Errorf("invalid range: %q", input)
	}

	end, err := strconv.ParseInt(splits[1], 0, 64)
	if err != nil {
		return 0, 0, fmt.Errorf("invalid range: %q", input)
	}

	return int(start), int(end), nil
}