package tools

import (
	"errors"
	"io"
	"io/fs"
	"os"
	"os/exec"
	"path/filepath"
	"strconv"
	"strings"
	"time"
	"velvettear/gosync/log"
	"velvettear/gosync/settings"
)

var sourceFiles map[string]int64

// unexported function(s)
func getSourceFiles() map[string]int64 {
	timestamp := time.Now()
	sourceFiles = map[string]int64{}
	if settings.SourceIsRemote() {
		log.Info("getting the list of remote source files...")
		error := fillRemoteSourceFiles()
		if error != nil {
			log.Fatal("encountered an error getting the list of remote source files", error.Error())
		}
	} else {
		source, _ := strings.CutSuffix(settings.Source, "/*")
		stats, error := os.Stat(source)
		if error != nil {
			log.Fatal("encountered an error getting stats for source", error.Error())
		}
		if stats.IsDir() {
			log.Info("scanning source...", source)
			filepath.WalkDir(source, fillSourceFiles)
		} else {
			sourceFiles[settings.Source] = stats.Size()
		}
	}
	log.InfoTimed("found "+strconv.Itoa(len(sourceFiles))+" source files", timestamp.UnixMilli())
	return sourceFiles
}

func fillRemoteSourceFiles() error {
	var arguments []string
	if len(settings.Password) > 0 {
		arguments = append(arguments, "-p", settings.Password)
	}
	arguments = append(arguments, "ssh")
	remote, path, _ := strings.Cut(settings.Source, ":")
	path, _ = strings.CutSuffix(path, "/*")
	if len(settings.User) > 0 {
		remote = settings.User + "@" + remote
	}
	arguments = append(arguments, remote, "find", "\""+path+"\"", "-type", "f", "-exec", "du", "-b", "{}", "\\;")
	cmd := exec.Command("sshpass", arguments...)
	stdout, stdoutError := cmd.StdoutPipe()
	stderr, stderrError := cmd.StderrPipe()
	cmd.Start()
	if stdoutError != nil {
		return stdoutError
	}
	if stderrError != nil {
		return stderrError
	}
	outBytes, stdoutError := io.ReadAll(stdout)
	if stdoutError != nil {
		return stdoutError
	}
	errorBytes, stderrError := io.ReadAll(stderr)
	if stderrError != nil {
		return stderrError
	}
	cmd.Wait()
	error := strings.TrimSpace(string(errorBytes))
	if len(error) > 0 {
		return errors.New(error)
	}
	for _, line := range strings.Split(string(outBytes), "\n") {
		if !strings.Contains(line, "\t") {
			continue
		}
		parts := strings.Split(line, "\t")
		size, error := strconv.ParseInt(parts[0], 10, 64)
		if error != nil {
			log.Warning("encountered an error getting the file size for file '"+path+"'", error.Error())
		}
		sourceFiles[parts[1]] = size
	}
	return nil
}

func fillSourceFiles(path string, dir fs.DirEntry, err error) error {
	if err != nil {
		return err
	}
	if dir.IsDir() {
		return nil
	}
	stats, error := os.Stat(path)
	if error != nil {
		log.Fatal("encountered an error getting stats for file", error.Error())
		return nil
	}
	sourceFiles[path] = stats.Size()
	return nil
}

func getSourceFileSize() int64 {
	var total int64
	for _, size := range sourceFiles {
		total += size
	}
	return total
}