package main

import (
	"bytes"
	"fmt"
	"io/ioutil"
	"os"
	"path/filepath"

	"git.ali33.ru/fcg-xvii/go-tools/text/config"
	_ "git.ali33.ru/fcg-xvii/go-tools/text/config/ini"
	"github.com/sirupsen/logrus"
)

var (
	logger          = logrus.New()
	SourceDir       = "."
	LogDir          = "."
	CommentPosition = "top"
	CommentLine     = 0
	CommentString   = ""
	FileExtensions  = []string{
		"go",
		"py",
	}
	CommentTemplates = map[string]string{
		"go":   "// %s",
		"py":   "# %s",
		"js":   "// %s",
		"html": "<!-- %s -->",
		"sh":   "# %s",
	}
	CommentTemplateDefault = "// %s"
)

func GetTemplate(ext string) string {
	res := CommentTemplateDefault
	if len(ext) > 0 {
		if tpl, check := CommentTemplates[ext[1:]]; check {
			res = tpl
		}
	}
	return res
}

func GetCommentString(ext string) string {
	tpl := GetTemplate(ext)
	return fmt.Sprintf(tpl, CommentString)
}

func GetCommentData(ext string) []byte {
	return []byte(GetCommentString(ext))
}

func CheckExtension(ext string) bool {
	if len(ext) == 0 {
		return false
	}
	ext = ext[1:]
	for _, lExt := range FileExtensions {
		if lExt == ext {
			return true
		}
	}
	return false
}

func CheckCommentExists(data []byte, ext string) bool {
	cData := GetCommentData(ext)
	switch CommentPosition {
	case "top":
		return bytes.Index(data, cData) == 0
	case "bottom":
		return bytes.Index(data, cData) == len(data)-len(cData)
	// todo line !!!
	default:
		return false
	}
}

func CommentAppend(data []byte, ext string) []byte {
	cData := GetCommentString(ext)
	switch CommentPosition {
	case "top":
		return append([]byte(cData+"\n"), data...)
	case "bottom":
		return append(data, []byte("\n"+cData)...)
	// todo line !!!
	default:
		return data
	}
}

func ReadDir(path string) {
	info, err := os.Stat(path)
	if err != nil {
		logger.WithFields(logrus.Fields{
			"dir_path": path,
			"err":      err,
		}).Warn("Read directory error")
		return
	}
	if !info.IsDir() {
		logger.WithFields(logrus.Fields{
			"dir_path": path,
			"err":      "Expected directory",
		}).Warn("Read directory error")
		return
	}
	items, err := os.ReadDir(path)
	if err != nil {
		logger.WithFields(logrus.Fields{
			"dir_path": path,
			"err":      err,
		}).Warn("Read directory error")
		return
	}
	for _, item := range items {
		itemPath := path + "/" + item.Name()
		if item.IsDir() {
			ReadDir(itemPath)
		} else {
			// check extension
			ext := filepath.Ext(itemPath)
			if !CheckExtension(ext) {
				continue
			}
			data, err := ioutil.ReadFile(itemPath)
			if err != nil {
				logger.WithFields(logrus.Fields{
					"file_path": itemPath,
					"err":       err,
				}).Error("File read error")
			}
			// check comment already exists
			if CheckCommentExists(data, ext) {
				logger.WithFields(logrus.Fields{
					"file_path": itemPath,
					"err":       "Comment already exists",
				}).Warn("pass")
				continue
			}
			// append comment
			f, err := os.OpenFile(itemPath, os.O_WRONLY|os.O_TRUNC, item.Type().Perm())
			if err != nil {
				logger.WithFields(logrus.Fields{
					"file_path": itemPath,
					"err":       err,
				}).Error("File write error")
			}
			f.Write(CommentAppend(data, ext))
			f.Close()
		}
	}
}

func main() {
	// parse config
	conf, err := config.FromFile("ini", "config.ini")
	if err != nil {
		logger.WithFields(logrus.Fields{
			"file": "config.ini",
		}).Panicf("CONFIG FILE IS NOT FOUND (%v)", err)
	}
	// setup variables
	conf.ValueSetup("source_dir", &SourceDir)
	conf.ValueSetup("log_dir", &LogDir)
	conf.ValueSetup("comment_position", &CommentPosition)
	conf.ValueSetup("comment_line", &CommentLine)
	conf.ValueSetup("comment_string", &CommentString)
	conf.ValueSetup("file_extensions", &FileExtensions)

	// read directory
	ReadDir(SourceDir)
}