package main

import (
	"context"
	"fmt"
	"image"
	"image/color"
	"image/draw"
	"image/png"
	"log/slog"
	"net/http"
	"os"
	"os/signal"
	"path/filepath"
	"syscall"
	"time"

	"github.com/go-chi/chi/v5"
	"github.com/go-chi/chi/v5/middleware"

	"qbank/internal/auth"
	"qbank/internal/config"
	"qbank/internal/db"
	"qbank/internal/handlers"
	"qbank/internal/llm"
)

func main() {
	cfg := config.Load()

	logger := slog.New(slog.NewJSONHandler(os.Stdout, nil))
	slog.SetDefault(logger)

	if err := os.MkdirAll(cfg.DataDir, 0755); err != nil {
		slog.Error("create data dir", "err", err)
		os.Exit(1)
	}

	database, err := db.Open(filepath.Join(cfg.DataDir, "qbank.db"))
	if err != nil {
		slog.Error("open database", "err", err)
		os.Exit(1)
	}
	defer database.Close()

	if err := db.Seed(database, cfg.AdminUsers); err != nil {
		slog.Error("seed users", "err", err)
		os.Exit(1)
	}

	repo := db.New(database)
	authMgr := auth.NewManager(database)
	renderer := handlers.NewRenderer("web/templates")
	llmClient := llm.New(cfg.OpenAIAPIKey, cfg.LLMModel)

	ensureIcons("web/static")

	authH := handlers.NewAuthHandler(authMgr, repo, renderer)
	homeH := handlers.NewHomeHandler(authMgr, renderer)
	uploadH := handlers.NewUploadHandler(authMgr, repo, llmClient, renderer, cfg.DataDir)

	r := chi.NewRouter()
	r.Use(middleware.RequestID)
	r.Use(requestLogger(logger))
	r.Use(middleware.Recoverer)
	r.Use(authMgr.SM.LoadAndSave)

	r.Get("/healthz", func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusOK)
		w.Write([]byte("OK"))
	})
	r.Get("/sw.js", func(w http.ResponseWriter, r *http.Request) {
		http.ServeFile(w, r, "web/static/sw.js")
	})
	r.Handle("/static/*", http.StripPrefix("/static/", http.FileServer(http.Dir("web/static"))))

	r.Get("/login", authH.LoginGet)
	r.Post("/login", authH.LoginPost)
	r.Post("/logout", authH.Logout)

	r.Group(func(r chi.Router) {
		r.Use(authMgr.RequireAuth)
		r.Get("/", homeH.Handle)
		r.Get("/upload", uploadH.UploadGet)
		r.Post("/upload", uploadH.UploadPost)
		r.Get("/import/{id}", uploadH.ImportGet)
		r.Post("/import/{id}", uploadH.ImportPost)
	})

	srv := &http.Server{
		Addr:         ":" + cfg.Port,
		Handler:      r,
		ReadTimeout:  15 * time.Second,
		WriteTimeout: 120 * time.Second, // LLM extraction can take a while
		IdleTimeout:  60 * time.Second,
	}

	go func() {
		slog.Info("server starting", "port", cfg.Port)
		if err := srv.ListenAndServe(); err != nil && err != http.ErrServerClosed {
			slog.Error("server error", "err", err)
			os.Exit(1)
		}
	}()

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

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

func ensureIcons(dir string) {
	for _, size := range []int{192, 512} {
		path := filepath.Join(dir, fmt.Sprintf("icon-%d.png", size))
		if _, err := os.Stat(path); err == nil {
			continue
		}
		img := image.NewRGBA(image.Rect(0, 0, size, size))
		blue := color.RGBA{R: 37, G: 99, B: 235, A: 255}
		draw.Draw(img, img.Bounds(), &image.Uniform{C: blue}, image.Point{}, draw.Src)
		f, err := os.Create(path)
		if err != nil {
			slog.Warn("create icon", "path", path, "err", err)
			continue
		}
		png.Encode(f, img)
		f.Close()
	}
}

func requestLogger(logger *slog.Logger) func(http.Handler) http.Handler {
	return func(next http.Handler) http.Handler {
		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			start := time.Now()
			ww := middleware.NewWrapResponseWriter(w, r.ProtoMajor)
			next.ServeHTTP(ww, r)
			logger.Info("request",
				"method", r.Method,
				"path", r.URL.Path,
				"status", ww.Status(),
				"duration_ms", time.Since(start).Milliseconds(),
				"request_id", middleware.GetReqID(r.Context()),
			)
		})
	}
}