package Filesystem

import (
	"PackageManager/Client/Database"
	"crypto/md5"
	"fmt"
	"io/ioutil"
	"os"
	"path/filepath"
	"strings"
	"time"
)

func HashFile(path string) (string, error) {
	var (
		Md5Hash   string
		hashBytes [16]byte
		file      *os.File
		e         error
	)

	file, e = os.Open(path)
	if e != nil {
		panic(e)
	}

	defer file.Close()

	body, e := ioutil.ReadAll(file)
	if e != nil {
		panic(e)
	}

	//Get the 16 bytes hash
	hashBytes = md5.Sum(body)

	//Convert the bytes to a string
	Md5Hash = fmt.Sprintf("%x", hashBytes)

	return Md5Hash, nil
}

func UpdateFilesystemHash() error {
	var (
		fileHash string
		rows     []Database.FilesystemHashRow
		e        error
	)

	e = filepath.Walk(".", func(path string, info os.FileInfo, e error) error {
		if e != nil {
			return e
		}

		// Ignore hidden files
		if strings.HasPrefix(info.Name(), ".") || strings.HasPrefix(path, ".") {
			return nil
		}

		// Ignore directories
		if info.IsDir() {
			return nil
		}

		fileHash, e = HashFile(path)

		if e != nil {
			return e
		}

		rows = append(rows, Database.FilesystemHashRow{
			Path:      path,
			Hash:      fileHash,
			UpdatedAt: info.ModTime(),
		})

		// TODO: If len(rows) > x, update the db and clear out rows, and continue

		return nil
	})

	if e != nil {
		panic(e)
	}

	return Database.FindOrCreateFileHash(rows)
}

func GetFilesystemDiff() (map[int]string, map[int]string, error) {
	var (
		fileHash      string
		hashes        []string = []string{}
		lastUpdatedAt time.Time
		dirtyFiles    map[int]string
		newFiles      map[int]string    = make(map[int]string)
		newFilesTmp   map[string]string = make(map[string]string)
		counter       int
		ok            bool
		e             error
	)

	lastUpdatedAt, e = Database.GetMostRecentTimestamp()
	if e != nil {
		return dirtyFiles, newFiles, e
	}

	e = filepath.Walk(".", func(path string, info os.FileInfo, e error) error {
		if e != nil {
			return e
		}

		// Ignore hidden files
		if strings.HasPrefix(info.Name(), ".") || strings.HasPrefix(path, ".") {
			return nil
		}

		// Ignore directories
		if info.IsDir() {
			return nil
		}

		fileHash, e = HashFile(path)

		if e != nil {
			return e
		}

		hashes = append(hashes, fileHash)

		if info.ModTime().After(lastUpdatedAt) {
			newFilesTmp[path] = path
		}

		// TODO: If len(rows) > x, update the db and clear out rows, and continue

		return nil
	})
	if e != nil {
		return dirtyFiles, newFiles, e
	}

	dirtyFiles, e = Database.FindModifiedFiles(hashes)
	if e != nil {
		return dirtyFiles, newFiles, e
	}

	for _, file := range dirtyFiles {
		_, ok = newFilesTmp[file]
		if ok {
			delete(newFilesTmp, file)
		}
	}

	counter = len(dirtyFiles)

	for _, file := range newFilesTmp {
		newFiles[counter] = file
		counter++
	}

	return dirtyFiles, newFiles, e
}