package main

import (
	"archive/tar"
	"bufio"
	"compress/gzip"
	"errors"
	"fmt"
	"io"
	"io/fs"
	"os"
	"os/exec"
	"path/filepath"
	"regexp"
	"strings"
	"time"
)

var safeFilenamePattern = regexp.MustCompile(`[^A-Za-z0-9_.-]`)

func (app *App) log_line(line string) {
	handle, err := os.OpenFile(app.paths.LogFile, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0600)
	if err != nil {
		return
	}
	defer handle.Close()
	_, _ = fmt.Fprintln(handle, line)
}

func load_logging_pref(path string) bool {
	file, err := os.Open(path)
	if err != nil {
		return false
	}
	defer file.Close()
	scanner := bufio.NewScanner(file)
	for scanner.Scan() {
		line := strings.TrimSpace(scanner.Text())
		if line == "" || strings.HasPrefix(line, "#") {
			continue
		}
		key, value, found := strings.Cut(line, "=")
		if !found || !strings.EqualFold(strings.TrimSpace(key), "saveSessionLogs") {
			continue
		}
		switch strings.ToLower(strings.TrimSpace(value)) {
		case "1", "true", "yes", "on":
			return true
		default:
			return false
		}
	}
	return false
}

func save_logging_pref(path string, enabled bool) error {
	return write_private_file(path, func(writer io.Writer) error {
		value := 0
		if enabled {
			value = 1
		}
		_, err := fmt.Fprintf(writer, "saveSessionLogs=%d\n", value)
		return err
	})
}

func sanitize_filename(value string) string {
	return safeFilenamePattern.ReplaceAllString(value, "_")
}

func prepare_session_log(logDir, serverName string) (string, error) {
	if err := os.MkdirAll(logDir, 0700); err != nil {
		return "", err
	}
	path := filepath.Join(logDir, fmt.Sprintf("%s-%s.log", sanitize_filename(serverName), time.Now().Format("2006-01-02")))
	handle, err := os.OpenFile(path, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0600)
	if err != nil {
		return "", err
	}
	if err := handle.Chmod(0600); err != nil {
		handle.Close()
		return "", err
	}
	if err := handle.Close(); err != nil {
		return "", err
	}
	return path, nil
}

func log_files(logDir string) ([]string, error) {
	entries, err := os.ReadDir(logDir)
	if err != nil {
		return nil, err
	}
	paths := []string{}
	for _, entry := range entries {
		if entry.Type().IsRegular() && strings.HasSuffix(entry.Name(), ".log") {
			paths = append(paths, filepath.Join(logDir, entry.Name()))
		}
	}
	return paths, nil
}

func create_log_archive(logDir, cacheDir string) (string, error) {
	paths, err := log_files(logDir)
	if err != nil {
		return "", err
	}
	if len(paths) == 0 {
		return "", fs.ErrNotExist
	}
	if err := os.MkdirAll(cacheDir, 0700); err != nil {
		return "", err
	}
	archiveFile, err := os.CreateTemp(cacheDir, "barnard-logs-*.tar.gz")
	if err != nil {
		return "", err
	}
	archivePath := archiveFile.Name()
	failed := true
	defer func() {
		if failed {
			_ = os.Remove(archivePath)
		}
	}()
	if err := archiveFile.Chmod(0600); err != nil {
		archiveFile.Close()
		return "", err
	}
	gzipWriter := gzip.NewWriter(archiveFile)
	tarWriter := tar.NewWriter(gzipWriter)
	for _, path := range paths {
		info, err := os.Stat(path)
		if err != nil {
			tarWriter.Close()
			gzipWriter.Close()
			archiveFile.Close()
			return "", err
		}
		header, err := tar.FileInfoHeader(info, "")
		if err != nil {
			tarWriter.Close()
			gzipWriter.Close()
			archiveFile.Close()
			return "", err
		}
		header.Name = filepath.Base(path)
		header.Mode = 0600
		if err := tarWriter.WriteHeader(header); err != nil {
			tarWriter.Close()
			gzipWriter.Close()
			archiveFile.Close()
			return "", err
		}
		file, err := os.Open(path)
		if err != nil {
			tarWriter.Close()
			gzipWriter.Close()
			archiveFile.Close()
			return "", err
		}
		_, copyErr := io.Copy(tarWriter, file)
		closeErr := file.Close()
		if copyErr != nil {
			tarWriter.Close()
			gzipWriter.Close()
			archiveFile.Close()
			return "", copyErr
		}
		if closeErr != nil {
			tarWriter.Close()
			gzipWriter.Close()
			archiveFile.Close()
			return "", closeErr
		}
	}
	if err := tarWriter.Close(); err != nil {
		gzipWriter.Close()
		archiveFile.Close()
		return "", err
	}
	if err := gzipWriter.Close(); err != nil {
		archiveFile.Close()
		return "", err
	}
	if err := archiveFile.Sync(); err != nil {
		archiveFile.Close()
		return "", err
	}
	if err := archiveFile.Close(); err != nil {
		return "", err
	}
	failed = false
	return archivePath, nil
}

func (app *App) send_logs() error {
	wormhole, err := exec.LookPath("wormhole")
	if err != nil {
		return app.ui.message("Required command not found: wormhole")
	}
	archivePath, err := create_log_archive(app.paths.LogDir, app.paths.CacheDir)
	if errors.Is(err, fs.ErrNotExist) || errors.Is(err, os.ErrNotExist) {
		return app.ui.message("No logs to send. Logs are saved to: " + app.paths.LogDir)
	}
	if err != nil {
		return app.ui.message("Could not create log archive: " + err.Error())
	}
	defer os.Remove(archivePath)

	if err := app.ui.message("Wormhole will display the transfer code in the normal terminal. Press Ctrl+C there to cancel the transfer."); err != nil {
		return err
	}
	command := exec.Command(wormhole, "send", archivePath)
	command.Stdin = os.Stdin
	command.Stdout = os.Stdout
	command.Stderr = os.Stderr
	app.ui.close()
	commandErr := run_external(app.ui, command)
	var signalErr *terminalSignalError
	if errors.As(commandErr, &signalErr) {
		return signalErr
	}
	if err := app.ui.open(); err != nil {
		return err
	}
	if receivedSignal := app.ui.take_termination(); receivedSignal != nil {
		return &terminalSignalError{signal: receivedSignal}
	}
	if commandErr == nil {
		app.log_line("Sent log archive with wormhole")
		return app.ui.message("Logs sent successfully.")
	}
	return app.ui.message("Log transfer did not complete successfully: " + commandErr.Error())
}

func (app *App) toggle_session_logging() error {
	question := "Session logging is currently disabled. Enable saving logs to the logs directory?"
	if app.saveSessionLogs {
		question = "Session logging is currently enabled. Disable it?"
	}
	confirmed, err := app.ui.confirm(question)
	if err != nil || !confirmed {
		return err
	}
	newValue := !app.saveSessionLogs
	if err := save_logging_pref(app.paths.LogPrefsFile, newValue); err != nil {
		return app.ui.message("Could not save logging preference: " + err.Error())
	}
	app.saveSessionLogs = newValue
	return nil
}

func (app *App) manage_logs() error {
	for {
		toggleLabel := "Enable logs"
		if app.saveSessionLogs {
			toggleLabel = "Disable logs"
		}
		options := []string{toggleLabel, "Send logs with wormhole", "Go Back"}
		selection, cancelled, err := app.ui.menu(options)
		if err != nil || cancelled || selection == len(options)-1 {
			return err
		}
		switch selection {
		case 0:
			err = app.toggle_session_logging()
		case 1:
			err = app.send_logs()
		}
		if err != nil {
			return err
		}
	}
}