package root

import (
	"fmt"
	"os"
	"path/filepath"
	"runtime"
	"strings"
	"sync"
	"syscall"
	"time"

	"github.com/spf13/cobra"
	"github.com/versenilvis/iris/internal/config"
)

// startRescueShell starts a fallback shell if the application crashes to keep the terminal open
func startRescueShell() {
	shell := os.Getenv("SHELL")
	if shell == "" {
		shell = "/bin/sh"
	}
	env := append(os.Environ(), "IRIS_RESCUE=1")
	_ = syscall.Exec(shell, []string{shell}, env)
}

var (
	lastCrashFile string
	lastCrashMu   sync.Mutex
)

// writeCrashLog writes the crash info and stack trace to a new log file
func WriteCrashLog(err any) {
	dir, errDir := config.CrashDir()
	if errDir != nil {
		return
	}
	_ = os.MkdirAll(dir, 0755)
	logFile := filepath.Join(dir, fmt.Sprintf("crash_%s.log", time.Now().Format("20060102_150405")))

	lastCrashMu.Lock()
	lastCrashFile = logFile
	lastCrashMu.Unlock()

	f, errOpen := os.OpenFile(logFile, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0600)
	if errOpen != nil {
		return
	}
	defer f.Close()

	_, _ = fmt.Fprintf(f, "=== IRIS CRASH %s ===\n", time.Now().Format(time.RFC3339))
	_, _ = fmt.Fprintf(f, "version: %s\nos: %s/%s\n\n", Version, runtime.GOOS, runtime.GOARCH)
	_, _ = fmt.Fprintf(f, "panic: %v\n\n", err)

	var n int
	buf := make([]byte, 1024)
	for {
		n = runtime.Stack(buf, true)
		if n < len(buf) {
			break
		}
		buf = make([]byte, 2*len(buf))
	}
	_, _ = f.Write(buf[:n])
	_, _ = fmt.Fprintln(f)
}

// getLatestCrashLog returns the path to the newest crash log file
func getLatestCrashLog() string {
	dir, errDir := config.CrashDir()
	if errDir != nil {
		return ""
	}
	files, err := os.ReadDir(dir)
	if err != nil || len(files) == 0 {
		home, errHome := os.UserHomeDir()
		if errHome == nil {
			oldLog := filepath.Join(home, ".iris", "crash.log")
			if _, err := os.Stat(oldLog); err == nil {
				return oldLog
			}
			oldCrashes := filepath.Join(home, ".iris", "crashes")
			if oldFiles, errOld := os.ReadDir(oldCrashes); errOld == nil && len(oldFiles) > 0 {
				var latestOld string
				for _, f := range oldFiles {
					if f.IsDir() {
						continue
					}
					name := f.Name()
					if strings.HasPrefix(name, "crash_") && strings.HasSuffix(name, ".log") {
						if name > latestOld {
							latestOld = name
						}
					}
				}
				if latestOld != "" {
					return filepath.Join(oldCrashes, latestOld)
				}
			}
		}
		return ""
	}

	var latest string
	for _, f := range files {
		if f.IsDir() {
			continue
		}
		name := f.Name()
		if strings.HasPrefix(name, "crash_") && strings.HasSuffix(name, ".log") {
			if name > latest {
				latest = name
			}
		}
	}
	if latest == "" {
		home, errHome := os.UserHomeDir()
		if errHome == nil {
			oldLog := filepath.Join(home, ".iris", "crash.log")
			if _, err := os.Stat(oldLog); err == nil {
				return oldLog
			}
		}
		return ""
	}
	return filepath.Join(dir, latest)
}

// printCrashNotice prints the crash notice with absolute path to the log file
func printCrashNotice() {
	lastCrashMu.Lock()
	logFile := lastCrashFile
	lastCrashMu.Unlock()
	if logFile == "" {
		logFile = getLatestCrashLog()
	}
	_, _ = fmt.Fprintf(os.Stderr, "\n\033[31m[IRIS] crashed, report saved to %s\033[0m\n", logFile)
}

var (
	// crashCmd is the cobra command to manage crash logs
	CrashCmd = &cobra.Command{
		Use:   "crash-log",
		Short: "manage iris crash logs",
		Run: func(cmd *cobra.Command, args []string) {
			if ClearLog {
				dir, errDir := config.CrashDir()
				if errDir == nil {
					_ = os.RemoveAll(dir)
				}
				home, errHome := os.UserHomeDir()
				if errHome == nil {
					_ = os.RemoveAll(filepath.Join(home, ".iris", "crashes"))
					_ = os.Remove(filepath.Join(home, ".iris", "crash.log"))
				}
				cmd.Println("crash log cleared")
				return
			}

			logFile := getLatestCrashLog()
			if logFile == "" {
				cmd.Println("no crash log found")
				return
			}
			cmd.Println(logFile)
		},
	}
	// clearLog is the flag to clear the crash log
	ClearLog bool
)

func init() {
	CrashCmd.Flags().BoolVar(&ClearLog, "clear", false, "clear the crash log")
	rootCmd.AddCommand(CrashCmd)
}