package main

import (
	"context"
	"database/sql"
	"encoding/json"
	"errors"
	"fmt"
	"net/http"
	"os"
	"os/signal"
	"syscall"
	"time"

	"forgejo.digital-droplets.de/philschlo/proxui/platform/config"
	"forgejo.digital-droplets.de/philschlo/proxui/platform/logging"
	_ "github.com/jackc/pgx/v5/stdlib"

	"proxui/backend/internal/auth"
	"proxui/backend/internal/authorization"
	"proxui/backend/internal/cluster"
	"proxui/backend/internal/clusteradmin"
	"proxui/backend/internal/encryption"
	"proxui/backend/internal/membership"
	"proxui/backend/internal/operator"
	"proxui/backend/internal/profile"
	"proxui/backend/internal/rbac"
)

func main() {
	cfg, err := config.Load()
	if err != nil {
		logger := logging.New("backend", "unknown", 0)
		logger.Error("failed to load config", "error", err)
		os.Exit(1)
	}

	logger := logging.New("backend", cfg.AppEnv, cfg.LogLevel)
	jwtValidator, err := auth.NewValidator(
		cfg.SupabaseIssuer,
		cfg.SupabaseJWKSURL,
		auth.WithHMACSecret(cfg.SupabaseJWTSecret),
	)
	if err != nil {
		logger.Error("failed to initialize jwt validator", "error", err)
		os.Exit(1)
	}
	authMiddleware := auth.NewMiddleware(jwtValidator)
	tokenCipher, err := encryption.NewFromBase64(cfg.MasterKeyBase64)
	if err != nil {
		logger.Error("failed to initialize cluster token encryption", "error", err)
		os.Exit(1)
	}
	_ = tokenCipher

	db, err := openDatabase(cfg.DatabaseURL)
	if err != nil {
		logger.Error("failed to connect database", "error", err)
		os.Exit(1)
	}
	defer db.Close()

	profileMiddleware := profile.NewMiddleware(profile.NewRepository(db), logger)
	membershipMiddleware := membership.NewMiddleware(membership.NewRepository(db), logger)
	authorizationMiddleware := authorization.NewMiddleware()
	clusterRepository := cluster.NewRepository(db, tokenCipher)
	clusterAdminHandler := clusteradmin.NewHandler(clusterRepository)
	operatorMiddleware := operator.NewMiddleware(cfg.OperatorToken)

	mux := http.NewServeMux()
	mux.HandleFunc("GET /healthz", func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Content-Type", "application/json")
		_, _ = w.Write([]byte(`{"status":"ok","service":"backend"}`))
	})
	meHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		principal, _ := auth.PrincipalFromRequest(r)
		w.Header().Set("Content-Type", "application/json")
		_ = json.NewEncoder(w).Encode(principal)
	})
	mux.Handle("GET /me", authMiddleware.RequireAuth(profileMiddleware.EnsureProfile(meHandler)))
	tenantMembershipHandler := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		tenantMembership, _ := membership.FromRequest(r)
		w.Header().Set("Content-Type", "application/json")
		_ = json.NewEncoder(w).Encode(tenantMembership)
	})
	mux.Handle(
		"GET /tenants/{tenantID}/membership",
		authMiddleware.RequireAuth(
			profileMiddleware.EnsureProfile(
				membershipMiddleware.RequireTenantMembership(
					pathTenantID,
					authorizationMiddleware.Require(rbac.ActionProjectRead, tenantMembershipHandler),
				),
			),
		),
	)
	clusterManageChain := func(handler http.HandlerFunc) http.Handler {
		return operatorMiddleware.RequireOperator(authorizationMiddleware.Require(rbac.ActionClusterManage, handler))
	}
	mux.Handle("POST /internal/clusters", clusterManageChain(clusterAdminHandler.CreateCluster))
	mux.Handle("PUT /internal/clusters/{clusterID}", clusterManageChain(clusterAdminHandler.UpdateCluster))
	mux.Handle("PATCH /internal/clusters/{clusterID}/status", clusterManageChain(clusterAdminHandler.SetClusterStatus))

	server := &http.Server{
		Addr:              cfg.BackendAddr,
		Handler:           withCORS(cfg.AppSiteURL, mux),
		ReadHeaderTimeout: 5 * time.Second,
	}

	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
	defer stop()

	go func() {
		logger.Info("backend listening", "addr", cfg.BackendAddr)
		if err := server.ListenAndServe(); err != nil && !errors.Is(err, http.ErrServerClosed) {
			logger.Error("backend failed", "error", err)
			os.Exit(1)
		}
	}()

	<-ctx.Done()

	shutdownCtx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
	defer cancel()
	if err := server.Shutdown(shutdownCtx); err != nil {
		logger.Error("backend shutdown failed", "error", err)
		os.Exit(1)
	}
}

func pathTenantID(r *http.Request) (string, bool) {
	tenantID := r.PathValue("tenantID")
	return tenantID, tenantID != ""
}

func openDatabase(databaseURL string) (*sql.DB, error) {
	if databaseURL == "" {
		return nil, fmt.Errorf("DATABASE_URL is required")
	}

	db, err := sql.Open("pgx", databaseURL)
	if err != nil {
		return nil, err
	}
	if err := db.Ping(); err != nil {
		_ = db.Close()
		return nil, err
	}

	return db, nil
}

func withCORS(allowedOrigin string, next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		origin := r.Header.Get("Origin")
		if origin != "" && origin == allowedOrigin {
			w.Header().Set("Access-Control-Allow-Origin", allowedOrigin)
			w.Header().Set("Access-Control-Allow-Headers", "Authorization, Content-Type")
			w.Header().Set("Access-Control-Allow-Methods", "GET, POST, PUT, PATCH, DELETE, OPTIONS")
			w.Header().Set("Vary", "Origin")
		}

		if r.Method == http.MethodOptions {
			w.WriteHeader(http.StatusNoContent)
			return
		}

		next.ServeHTTP(w, r)
	})
}