package main

import (
	"fmt"
	"log"
	"os"
	"path/filepath"
	"time"

	"verstak/internal/core/config"
)

// appLogPath returns the path to the application log file.
// Uses ~/.local/state/verstak/logs/verstak.log on Linux,
// or falls back to ~/.config/verstak/logs/verstak.log.
func appLogPath() string {
	// Prefer XDG_STATE_HOME, then fallback to config dir
	stateDir := os.Getenv("XDG_STATE_HOME")
	if stateDir == "" {
		home, err := os.UserHomeDir()
		if err == nil {
			stateDir = filepath.Join(home, ".local", "state")
		}
	}
	if stateDir != "" {
		dir := filepath.Join(stateDir, "verstak", "logs")
		if err := os.MkdirAll(dir, 0o755); err == nil {
			return filepath.Join(dir, "verstak.log")
		}
	}
	// Fallback to config dir
	cfgDir, err := config.EnsureConfigDir()
	if err != nil {
		return ""
	}
	dir := filepath.Join(cfgDir, "logs")
	if err := os.MkdirAll(dir, 0o755); err != nil {
		return ""
	}
	return filepath.Join(dir, "verstak.log")
}

// appLog writes a timestamped line to the application log file.
func appLog(level, msg string) {
	logPath := appLogPath()
	if logPath == "" {
		log.Printf("[%s] %s", level, msg)
		return
	}
	line := fmt.Sprintf("[%s] [%s] %s\n", time.Now().Format("2006-01-02T15:04:05"), level, msg)
	f, err := os.OpenFile(logPath, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0o644)
	if err != nil {
		log.Printf("[%s] %s", level, msg)
		return
	}
	defer f.Close()
	f.WriteString(line)
}

// FrontendLog receives log messages from the frontend runtime.
// Called from JS via Wails binding. Works even if vault is not open.
// level: "info", "warn", "error"
// message: human-readable message
// stack: JS stack trace (optional, only for errors)
func (a *App) FrontendLog(level, message, stack string) {
	msg := "[frontend] " + message
	if stack != "" {
		msg += "\n  stack: " + stack
	}
	// Always log to Go's standard logger (visible in dev mode console)
	log.Printf("[frontend][%s] %s", level, message)
	// Persist to log file
	appLog("frontend-"+level, msg)
}

// LogStartupStep logs a startup diagnostic step.
// Called from Go side to trace initialization progress.
func (a *App) LogStartupStep(step string, success bool, detail string) {
	status := "ok"
	if !success {
		status = "fail"
	}
	msg := fmt.Sprintf("[startup] %s: %s", step, status)
	if detail != "" {
		msg += " — " + detail
	}
	log.Print(msg)
	appLog("startup", msg)
}