package main

import (
	"bytes"
	"encoding/xml"
	"errors"
	"flag"
	"fmt"
	"io"
	"io/ioutil"
	"os"
	"path/filepath"
	"strings"
	"sync"

	"git.narnian.us/lordwelch/lsgo"
	_ "git.narnian.us/lordwelch/lsgo/lsb"
	_ "git.narnian.us/lordwelch/lsgo/lsf"

	"github.com/go-kit/kit/log"
	"github.com/kr/pretty"
)

var (
	write         = flag.Bool("w", false, "replace the file with xml data")
	printXML      = flag.Bool("x", false, "print xml to stdout")
	printResource = flag.Bool("R", false, "print the resource struct to stderr")
	recurse       = flag.Bool("r", false, "recurse into directories")
	logging       = flag.Bool("l", false, "enable logging to stderr")
	parts         = flag.String("p", "", "parts to filter logging for, comma separated")
)

func init() {
	flag.Parse()
	if *logging {
		lsgo.Logger = lsgo.NewFilter(map[string][]string{
			"part": strings.Split(*parts, ","),
		}, log.NewLogfmtLogger(os.Stderr))
	}
}

func main() {

	for _, v := range flag.Args() {
		fi, err := os.Stat(v)
		if err != nil {
			fmt.Fprintln(os.Stderr, err)
			os.Exit(1)
		}
		switch {

		case !fi.IsDir():
			err = openLSF(v)
			if err != nil && !errors.As(err, &lsgo.HeaderError{}) {
				fmt.Fprintln(os.Stderr, err)
				os.Exit(1)
			}

		case *recurse:
			_ = filepath.Walk(v, func(path string, info os.FileInfo, err error) error {
				if err != nil {
					return nil
				}
				if info.IsDir() {
					if info.Name() == ".git" {
						return filepath.SkipDir
					}
					return nil
				}
				err = openLSF(path)
				if err != nil && !errors.As(err, &lsgo.HeaderError{}) {
					fmt.Fprintln(os.Stderr, err)
				}
				return nil
			})

		default:
			fmt.Fprintf(os.Stderr, "lsconvert: %s: Is a directory\n", v)
			os.Exit(1)
		}
	}
}

func openLSF(filename string) error {
	var (
		l   *lsgo.Resource
		err error
		n   string
		f   interface {
			io.Writer
			io.StringWriter
		}
	)
	l, err = readLSF(filename)
	if err != nil {
		return fmt.Errorf("reading LSF file %s failed: %w", filename, err)
	}
	if *printResource {
		pretty.Log(l)
	}
	if *printXML || *write {
		n, err = marshalXML(l)
		if err != nil {
			return fmt.Errorf("creating XML from LSF file %s failed: %w", filename, err)
		}

		if *write {
			f, err = os.OpenFile(filename, os.O_TRUNC|os.O_RDWR, 0o666)
			if err != nil {
				return fmt.Errorf("writing XML from LSF file %s failed: %w", filename, err)
			}
		} else if *printXML {
			f = os.Stdout
		}

		err = writeXML(f, n)
		fmt.Fprint(f, "\n")
		if err != nil {
			return fmt.Errorf("writing XML from LSF file %s failed: %w", filename, err)
		}
	}
	return nil
}

func readLSF(filename string) (*lsgo.Resource, error) {
	var (
		l    lsgo.Resource
		r    io.ReadSeeker
		file *os.File
		fi   os.FileInfo
		err  error
	)
	switch filepath.Ext(filename) {

	case ".lsf", ".lsb":
		var b []byte
		fi, err = os.Stat(filename)
		if err != nil {
			return nil, err
		}
		// Arbitrary size, no lsf file should reach 100 MB (I haven't found one over 90 KB) and if you don't have 100 MB of ram free you shouldn't be using this
		if fi.Size() <= 100*1024*1024 {
			b, err = ioutil.ReadFile(filename)
			if err != nil {
				return nil, err
			}
			r = bytes.NewReader(b)
			break
		}
		fallthrough
	default:
		b := make([]byte, 4)
		file, err = os.Open(filename)
		if err != nil {
			return nil, err
		}
		defer file.Close()

		_, err = file.Read(b)
		if err != nil {
			return nil, err
		}
		if !lsgo.SupportedFormat(b) {
			return nil, lsgo.ErrFormat
		}

		_, err = file.Seek(0, io.SeekStart)
		if err != nil {
			return nil, err
		}
		fi, _ = os.Stat(filename)

		// I have never seen a valid "ls*" file over 90 KB
		if fi.Size() < 1*1024*1024 {
			b, err = ioutil.ReadAll(file)
			if err != nil {
				return nil, err
			}
			r = bytes.NewReader(b)
		} else {
			r = file
		}
	}

	l, _, err = lsgo.Decode(r)
	if err != nil {
		return nil, err
	}
	return &l, nil
}

func marshalXML(l *lsgo.Resource) (string, error) {
	var (
		v   []byte
		err error
	)
	v, err = xml.MarshalIndent(struct {
		*lsgo.Resource
		XMLName string `xml:"save"`
	}{l, ""}, "", "\t")
	if err != nil {
		return string(v), err
	}
	n := string(v)
	n = strings.ReplaceAll(n, "></version>", " />")
	n = strings.ReplaceAll(n, "></attribute>", " />")
	n = strings.ReplaceAll(n, "></node>", " />")
	n = strings.ReplaceAll(n, "false", "False")
	n = strings.ReplaceAll(n, "true", "True")
	n = strings.ReplaceAll(n, "&#39;", "'")
	n = strings.ReplaceAll(n, "&#34;", "&quot;")
	return n, nil
}

func writeXML(f io.StringWriter, n string) error {
	var err error
	_, err = f.WriteString(strings.ToLower(xml.Header))
	if err != nil {
		return err
	}
	_, err = f.WriteString(n)
	if err != nil {
		return err
	}
	return nil
}