package main

import (
	"context"
	"embed"
	"flag"
	"io"
	"io/fs"
	"log/slog"
	"net/http"
	"os"
	"os/signal"
	"syscall"
	"time"

	"github.com/gin-gonic/gin"

	"zeromesh/internal/config"
	"zeromesh/internal/controller"
	"zeromesh/internal/database"
	"zeromesh/internal/router"
)

//go:embed web/dist/index.html web/dist/assets/*
var webDist embed.FS

func main() {
	cfgPath := flag.String("config", "config.yaml", "config file path")
	flag.Parse()

	cfg, err := config.Load(*cfgPath)
	if err != nil {
		slog.Error("load config", "err", err)
		os.Exit(1)
	}

	logLevel := new(slog.LevelVar)
	switch cfg.Logging.Level {
	case "debug":
		logLevel.Set(slog.LevelDebug)
	case "warn":
		logLevel.Set(slog.LevelWarn)
	case "error":
		logLevel.Set(slog.LevelError)
	default:
		logLevel.Set(slog.LevelInfo)
	}
	opts := &slog.HandlerOptions{Level: logLevel}
	var logHandler slog.Handler
	if cfg.Logging.Format == "json" {
		logHandler = slog.NewJSONHandler(os.Stderr, opts)
	} else {
		logHandler = slog.NewTextHandler(os.Stderr, opts)
	}
	logger := slog.New(logHandler)
	slog.SetDefault(logger)

	db, err := database.Init(&cfg.Database)
	if err != nil {
		slog.Error("init database", "err", err)
		os.Exit(1)
	}

	ctr, err := controller.New(cfg, db, logger)
	if err != nil {
		slog.Error("init controller", "err", err)
		os.Exit(1)
	}
	if err := ctr.Start(); err != nil {
		slog.Error("start controller", "err", err)
		os.Exit(1)
	}

	gin.SetMode(gin.ReleaseMode)
	ginEngine := router.Setup(cfg, db)

	webFS, _ := fs.Sub(webDist, "web/dist")
	// Wrap in a Handler that serves SPA before Gin gets a chance to redirect
	handler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		p := r.URL.Path
		// Serve SPA for root and all non-API paths
		if p == "/" || p == "/index.html" {
			w.Header().Set("Content-Type", "text/html; charset=utf-8")
			data, err := webFS.Open("index.html")
			if err == nil {
				http.ServeContent(w, r, "index.html", time.Now(), data.(io.ReadSeeker))
				return
			}
		}
		if len(p) >= 8 && p[:8] == "/assets/" {
			assetFS, _ := fs.Sub(webDist, "web/dist/assets")
			http.StripPrefix("/assets", http.FileServer(http.FS(assetFS))).ServeHTTP(w, r)
			return
		}
		// API routes go to Gin
		if len(p) >= 4 && p[:4] == "/api" {
			ginEngine.ServeHTTP(w, r)
			return
		}
		// SPA fallback for all other routes
		w.Header().Set("Content-Type", "text/html; charset=utf-8")
		data, err := webFS.Open("index.html")
		if err == nil {
			http.ServeContent(w, r, "index.html", time.Now(), data.(io.ReadSeeker))
			return
		}
		ginEngine.ServeHTTP(w, r)
	})

	srv := &http.Server{
		Addr:    cfg.Server.Addr(),
		Handler: handler,
	}

	go func() {
		slog.Info("server listening", "addr", srv.Addr)
		if err := srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
			slog.Error("serve", "err", err)
		}
	}()

	quit := make(chan os.Signal, 1)
	signal.Notify(quit, syscall.SIGINT, syscall.SIGTERM)
	<-quit

	slog.Info("shutting down...")
	ctr.Stop()
	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()
	if err := srv.Shutdown(ctx); err != nil {
		slog.Error("shutdown", "err", err)
	}
}