package crashlog

import (
	"fmt"
	"os"
	"path/filepath"
	"runtime/debug"
	"sync"
	"time"

	"tea.chunkbyte.com/kato/go-worm/lib/config"
)

var mu sync.Mutex

// Recover logs a panic without re-raising (used by optional defer wrappers).
func Recover() {
	if r := recover(); r != nil {
		_ = write("panic", fmt.Sprint(r), debug.Stack())
	}
}

// RecordPanic writes a recovered panic without exiting (e.g. HTTP handlers).
func RecordPanic(recovered any) {
	_ = write("panic", fmt.Sprint(recovered), debug.Stack())
}

// RecordError writes a fatal error before exit.
func RecordError(err error) {
	if err == nil {
		return
	}
	_ = write("fatal", err.Error(), debug.Stack())
}

func write(kind, detail string, stack []byte) error {
	dir, err := config.LogsDir()
	if err != nil {
		return err
	}
	mu.Lock()
	defer mu.Unlock()
	if err := os.MkdirAll(dir, 0o700); err != nil {
		return err
	}
	name := fmt.Sprintf("crash-%s.log", time.Now().Format("2006-01-02-150405"))
	path := filepath.Join(dir, name)
	body := fmt.Sprintf(
		"time: %s\nversion: %s\nkind: %s\ndetail: %s\n\nstack:\n%s",
		time.Now().Format(time.RFC3339Nano),
		config.Version,
		kind,
		detail,
		stack,
	)
	return os.WriteFile(path, []byte(body), 0o600)
}