package main

import (
	"context"
	"fmt"
	"log/slog"
	"net/http"
	"os"
	"os/signal"
	"syscall"
	"time"

	"github.com/go-chi/chi/v5"
	"github.com/go-chi/chi/v5/middleware"
	"github.com/go-chi/cors"
	"github.com/joho/godotenv"

	"git.seaofstars.xyz/mohd/deflated/internal/db"
	"git.seaofstars.xyz/mohd/deflated/internal/handlers"
)

func main() {
	// Load .env file if present (ignored in production)
	_ = godotenv.Load()

	// Structured logger — prints human-readable text locally, JSON in prod
	logger := slog.New(slog.NewTextHandler(os.Stdout, &slog.HandlerOptions{
		Level: slog.LevelDebug,
	}))
	slog.SetDefault(logger)

	// Connect to Postgres
	pool, err := db.Connect(os.Getenv("DATABASE_URL"))
	if err != nil {
		slog.Error("failed to connect to database", "error", err)
		os.Exit(1)
	}
	defer pool.Close()

	// Run migrations on startup
	if err := db.Migrate(pool); err != nil {
		slog.Error("failed to run migrations", "error", err)
		os.Exit(1)
	}

	// Wire up dependencies
	queries := db.New(pool)
	receiptHandler := handlers.NewReceiptHandler(queries)
	itemHandler := handlers.NewItemHandler(queries)

	// Build router
	r := chi.NewRouter()

	// Middleware stack (runs for every request, in order)
	r.Use(middleware.RequestID)   // adds X-Request-ID header
	r.Use(middleware.RealIP)      // reads X-Forwarded-For for real client IP
	r.Use(middleware.Logger)      // logs method, path, status, duration
	r.Use(middleware.Recoverer)   // catches panics, returns 500 instead of crashing
	r.Use(middleware.Compress(5)) // gzip responses

	r.Use(cors.Handler(cors.Options{
		AllowedOrigins: []string{"http://localhost:5173", os.Getenv("FRONTEND_URL")},
		AllowedMethods: []string{"GET", "POST", "OPTIONS"},
		AllowedHeaders: []string{"Accept", "Content-Type"},
	}))

	// Routes
	r.Get("/health", func(w http.ResponseWriter, r *http.Request) {
		w.WriteHeader(http.StatusOK)
		fmt.Fprint(w, "ok")
	})

	r.Route("/api", func(r chi.Router) {
		r.Post("/receipts", receiptHandler.Submit)
		r.Get("/receipts/{id}", receiptHandler.Get)

		r.Get("/items", itemHandler.List)
		r.Get("/items/{name}/history", itemHandler.PriceHistory)
		r.Get("/items/top-movers", itemHandler.TopMovers)

		r.Get("/inflation/summary", itemHandler.InflationSummary)
	})

	// Server with graceful shutdown
	port := os.Getenv("PORT")
	if port == "" {
		port = "8080"
	}

	srv := &http.Server{
		Addr:         ":" + port,
		Handler:      r,
		ReadTimeout:  15 * time.Second,
		WriteTimeout: 30 * time.Second,
		IdleTimeout:  60 * time.Second,
	}

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

	// Block until SIGINT or SIGTERM (Ctrl+C or `docker stop`)
	quit := make(chan os.Signal, 1)
	signal.Notify(quit, syscall.SIGINT, syscall.SIGTERM)
	<-quit

	slog.Info("shutting down gracefully...")
	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()

	if err := srv.Shutdown(ctx); err != nil {
		slog.Error("forced shutdown", "error", err)
	}
}