package main

import (
	"context"
	"crypto/sha256"
	"crypto/subtle"
	"encoding/base64"
	"errors"
	"io"
	"net"
	"net/url"
	"os"
	"os/signal"
	"path/filepath"
	"strconv"
	"strings"
	"syscall"
	"time"

	"git.ipao.vip/rogee/creator-hub/internal/creator"
	"git.ipao.vip/rogee/creator-hub/internal/hub"
	"git.ipao.vip/rogee/creator-hub/internal/phasea"
	"git.ipao.vip/rogee/creator-hub/internal/taskstate"
	"github.com/gofiber/fiber/v3"
	"github.com/sirupsen/logrus"
	"github.com/spf13/cobra"
	"github.com/spf13/viper"
)

type config struct {
	listenAddr, webDir, databaseURL, credentialStoreDir string
	username, password                                  string
	aiAPIKey, aiBaseURL                                 string
	credentialMasterKey                                 []byte
	logLevel                                            logrus.Level
}

func main() {
	logrus.SetFormatter(&logrus.JSONFormatter{})
	if err := execute(newCommand()); err != nil {
		logrus.WithField("service", "control-plane").WithError(err).Error("service stopped")
		os.Exit(1)
	}
}

func execute(command *cobra.Command) error {
	ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
	defer stop()
	return command.ExecuteContext(ctx)
}

func newCommand() *cobra.Command {
	command := &cobra.Command{
		Use:           "control-plane",
		Short:         "Run the CreatorHub control plane",
		Args:          cobra.NoArgs,
		SilenceErrors: true,
		SilenceUsage:  true,
		RunE: func(command *cobra.Command, _ []string) error {
			cfg, err := loadConfig()
			if err != nil {
				return err
			}
			credentials, err := newPersistentCredentialBridge(cfg.credentialStoreDir, cfg.credentialMasterKey)
			if err != nil {
				return err
			}
			logrus.SetLevel(cfg.logLevel)
			phaseAStore, err := phasea.Open(command.Context(), cfg.databaseURL)
			if err != nil {
				return err
			}
			defer phaseAStore.Close()
			hubStore, err := hub.Open(command.Context(), cfg.databaseURL)
			if err != nil {
				return err
			}
			defer hubStore.Close()
			creatorStore, err := creator.Open(command.Context(), cfg.databaseURL)
			if err != nil {
				return err
			}
			defer creatorStore.Close()
			creatorStore.SetSecretBridge(creatorSecretBridge{bridge: credentials})
			notify := newAttentionNotifier(os.Stderr)
			phaseAStore.SetTaskNotifier(notify)
			hubStore.SetTaskNotifier(notify)
			logStartup(cfg)
			heartbeatContext, stopHeartbeat := context.WithCancel(command.Context())
			heartbeatDone := make(chan struct{})
			go func() {
				defer close(heartbeatDone)
				runtimeLeaseHeartbeat(heartbeatContext, hubStore)
			}()
			creatorScheduleContext, stopCreatorScheduler := context.WithCancel(command.Context())
			creatorScheduleDone := make(chan struct{})
			go func() {
				defer close(creatorScheduleDone)
				runCreatorScheduler(creatorScheduleContext, creatorStore, phaseAStore, hubStore)
			}()
			creatorEventContext, stopCreatorEvents := context.WithCancel(command.Context())
			creatorEventDone := make(chan struct{})
			creatorEventExecutor := creatorGatewayActionExecutor{store: creatorStore, phaseAStore: phaseAStore, hubStore: hubStore}
			creatorAI := &creator.ConfiguredBailian{Store: creatorStore, APIKey: cfg.aiAPIKey, BaseURL: cfg.aiBaseURL}
			go func() {
				defer close(creatorEventDone)
				runCreatorEventListeners(creatorEventContext, creatorStore, phaseAStore, hubStore, creatorEventExecutor, creatorAI)
			}()
			listenErr := newHandlerWithCreatorAndAI(cfg.webDir, cfg.username, cfg.password, phaseAStore, hubStore, credentials, creatorStore, creatorAI, creatorAI).Listen(cfg.listenAddr, fiber.ListenConfig{
				GracefulContext:       command.Context(),
				DisableStartupMessage: true,
			})
			stopCreatorScheduler()
			stopCreatorEvents()
			stopHeartbeat()
			<-creatorScheduleDone
			<-creatorEventDone
			<-heartbeatDone
			return listenErr
		},
	}
	return command
}

func newAttentionNotifier(output io.Writer) taskstate.Notifier {
	logger := logrus.New()
	logger.SetFormatter(&logrus.JSONFormatter{})
	logger.SetOutput(output)
	return func(transition taskstate.Transition) {
		if transition.State != "policy_hold" && transition.State != "needs_confirmation" {
			return
		}
		logger.WithFields(logrus.Fields{
			"service": "control-plane", "notification_channel": "structured_log", "event_type": transition.State,
			"reason_code": transition.ReasonCode, "account_id": transition.AccountID, "task_id": transition.TaskID,
		}).Warn("operator attention required")
	}
}

func runtimeLeaseHeartbeat(ctx context.Context, store hubStore) {
	ticker := time.NewTicker(20 * time.Second)
	defer ticker.Stop()
	for {
		select {
		case <-ctx.Done():
			return
		case <-ticker.C:
			if err := reconcileRuntimeLeases(ctx, store, defaultNetworkExitProbe(), nil); err != nil && ctx.Err() == nil {
				logrus.WithField("service", "control-plane").WithError(err).Warn("runtime lease reconciliation failed")
			}
		}
	}
}

func logStartup(cfg config) {
	logrus.WithFields(logrus.Fields{
		"service":     "control-plane",
		"listen_addr": cfg.listenAddr,
	}).Info("service starting")
}

func loadConfig() (config, error) {
	v := viper.New()
	v.SetDefault("listen_addr", ":8080")
	v.SetDefault("web_dir", "web/dist")
	v.SetDefault("database_url", "postgres://creatorhub@127.0.0.1:5432/creatorhub?sslmode=disable")
	v.SetDefault("credential_store_dir", "/var/lib/creatorhub/credentials")
	v.SetDefault("log_level", "info")
	_ = v.BindEnv("listen_addr", "LISTEN_ADDR")
	_ = v.BindEnv("web_dir", "WEB_DIR")
	_ = v.BindEnv("database_url", "DATABASE_URL")
	_ = v.BindEnv("credential_store_dir", "CREATORHUB_CREDENTIAL_STORE_DIR")
	_ = v.BindEnv("credential_master_key", "CREATORHUB_CREDENTIAL_MASTER_KEY")
	_ = v.BindEnv("log_level", "LOG_LEVEL")
	_ = v.BindEnv("username", "CONTROL_PLANE_USERNAME")
	_ = v.BindEnv("password", "CONTROL_PLANE_PASSWORD")
	_ = v.BindEnv("ai_api_key", "BAILIAN_API_KEY")
	_ = v.BindEnv("ai_base_url", "BAILIAN_BASE_URL")

	level, err := logrus.ParseLevel(v.GetString("log_level"))
	if err != nil {
		return config{}, errors.New("LOG_LEVEL must be panic, fatal, error, warn, info, debug, or trace")
	}
	cfg := config{
		listenAddr:         strings.TrimSpace(v.GetString("listen_addr")),
		webDir:             strings.TrimSpace(v.GetString("web_dir")),
		databaseURL:        strings.TrimSpace(v.GetString("database_url")),
		credentialStoreDir: strings.TrimSpace(v.GetString("credential_store_dir")),
		username:           strings.TrimSpace(v.GetString("username")),
		password:           v.GetString("password"),
		aiAPIKey:           strings.TrimSpace(v.GetString("ai_api_key")),
		aiBaseURL:          strings.TrimSpace(v.GetString("ai_base_url")),
		logLevel:           level,
	}
	if cfg.listenAddr == "" {
		return config{}, errors.New("LISTEN_ADDR must not be empty")
	}
	if err := validateListenAddr(cfg.listenAddr); err != nil {
		return config{}, err
	}
	if cfg.webDir == "" {
		return config{}, errors.New("WEB_DIR must not be empty")
	}
	if cfg.username == "" || strings.Contains(cfg.username, ":") {
		return config{}, errors.New("CONTROL_PLANE_USERNAME must be non-empty and contain no colon")
	}
	if len(cfg.password) < 6 {
		return config{}, errors.New("CONTROL_PLANE_PASSWORD must contain at least 6 bytes")
	}
	if !filepath.IsAbs(cfg.credentialStoreDir) {
		return config{}, errors.New("CREATORHUB_CREDENTIAL_STORE_DIR must be absolute")
	}
	cfg.credentialMasterKey, err = base64.StdEncoding.DecodeString(strings.TrimSpace(v.GetString("credential_master_key")))
	if err != nil || len(cfg.credentialMasterKey) != 32 {
		return config{}, errors.New("CREATORHUB_CREDENTIAL_MASTER_KEY must be base64 for exactly 32 bytes")
	}
	databaseURL, err := url.Parse(cfg.databaseURL)
	if err != nil || databaseURL.Host == "" || databaseURL.Path == "" || databaseURL.Path == "/" ||
		(databaseURL.Scheme != "postgres" && databaseURL.Scheme != "postgresql") {
		return config{}, errors.New("DATABASE_URL must be a postgres URL with a host")
	}
	if cfg.aiBaseURL != "" {
		aiURL, parseErr := url.Parse(cfg.aiBaseURL)
		if parseErr != nil || aiURL.Host == "" || (aiURL.Scheme != "http" && aiURL.Scheme != "https") || aiURL.User != nil {
			return config{}, errors.New("BAILIAN_BASE_URL must be an HTTP(S) URL without credentials")
		}
	}
	return cfg, nil
}

func validateListenAddr(addr string) error {
	_, port, err := net.SplitHostPort(addr)
	if err != nil {
		return errors.New("LISTEN_ADDR must be a host:port address")
	}
	number, err := strconv.Atoi(port)
	if err != nil || number < 1 || number > 65535 {
		return errors.New("LISTEN_ADDR port must be 1..65535")
	}
	return nil
}

func newHandler(webDirectory, username, password string) *fiber.App {
	return newHandlerWithStores(webDirectory, username, password, nil, nil)
}

func newHandlerWithStores(webDirectory, username, password string, phaseAStore *phasea.Store, hubStore *hub.Store) *fiber.App {
	return newHandlerWithCredentialBridge(webDirectory, username, password, phaseAStore, hubStore, nil)
}

type creatorSecretBridge struct {
	bridge phasea.CredentialBridge
}

func (b creatorSecretBridge) Store(ctx context.Context, reference creator.SecretReference, key, value string) error {
	if b.bridge == nil {
		return errors.New("credential bridge is unavailable")
	}
	return b.bridge.Store(ctx, phasea.CredentialReference{ID: reference.ID, Provider: reference.Provider}, key, value)
}

func (b creatorSecretBridge) Delete(ctx context.Context, reference creator.SecretReference, key string) error {
	if b.bridge == nil {
		return errors.New("credential bridge is unavailable")
	}
	return b.bridge.Delete(ctx, phasea.CredentialReference{ID: reference.ID, Provider: reference.Provider}, key)
}

func newHandlerWithCredentialBridge(webDirectory, username, password string, phaseAStore *phasea.Store, hubStore *hub.Store, credentials phasea.CredentialBridge) *fiber.App {
	return newHandlerWithCreator(webDirectory, username, password, phaseAStore, hubStore, credentials, nil)
}

func newHandlerWithCreator(webDirectory, username, password string, phaseAStore *phasea.Store, hubStore *hub.Store, credentials phasea.CredentialBridge, creatorStore *creator.Store) *fiber.App {
	return newHandlerWithCreatorAndAI(webDirectory, username, password, phaseAStore, hubStore, credentials, creatorStore, nil, nil)
}

func newHandlerWithCreatorAndAI(webDirectory, username, password string, phaseAStore *phasea.Store, hubStore *hub.Store, credentials phasea.CredentialBridge, creatorStore *creator.Store, generator creator.TextGenerator, analyzer creator.ThemeAnalyzer) *fiber.App {
	app := fiber.New(fiber.Config{
		AppName:   "CreatorHub control plane",
		BodyLimit: 1 << 20,
		// 读超时只约束请求读取；创建/升级环境的处理器可等待网关拉取镜像（最长 11 分钟）。
		ReadTimeout: 5 * time.Second,
		IdleTimeout: 60 * time.Second,
	})
	app.Get("/healthz", func(c fiber.Ctx) error {
		c.Status(fiber.StatusNoContent)
		return nil
	})
	app.Use(authenticate(username, password))
	if hubStore != nil {
		registerHub(app, hubStore)
	}
	if phaseAStore != nil {
		registerPhaseA(app, phaseAStore, hubStore, credentials)
	}
	if creatorStore != nil {
		if generator == nil && analyzer == nil {
			registerCreator(app, creatorStore, phaseAStore, hubStore)
		} else {
			var executor creator.ActionExecutor
			if phaseAStore != nil && hubStore != nil {
				executor = creatorGatewayActionExecutor{store: creatorStore, phaseAStore: phaseAStore, hubStore: hubStore}
			}
			registerCreatorWithServices(app, creatorStore, phaseAStore, hubStore, executor, generator, analyzer)
		}
	}
	app.Get("/*", spaHandler(webDirectory))
	return app
}

func authenticate(username, password string) fiber.Handler {
	wantUser, wantPassword := sha256.Sum256([]byte(username)), sha256.Sum256([]byte(password))
	return func(c fiber.Ctx) error {
		encoded, ok := strings.CutPrefix(c.Get(fiber.HeaderAuthorization), "Basic ")
		decoded, err := base64.StdEncoding.DecodeString(encoded)
		user, suppliedPassword, found := strings.Cut(string(decoded), ":")
		gotUser, gotPassword := sha256.Sum256([]byte(user)), sha256.Sum256([]byte(suppliedPassword))
		userOK := subtle.ConstantTimeCompare(gotUser[:], wantUser[:])
		passwordOK := subtle.ConstantTimeCompare(gotPassword[:], wantPassword[:])
		if !ok || err != nil || !found || userOK != 1 || passwordOK != 1 {
			c.Set(fiber.HeaderWWWAuthenticate, `Basic realm="CreatorHub", charset="UTF-8"`)
			return c.Status(fiber.StatusUnauthorized).JSON(map[string]string{"error": "authentication required"})
		}
		return c.Next()
	}
}

func spaHandler(directory string) fiber.Handler {
	return func(c fiber.Ctx) error {
		path, err := url.PathUnescape(strings.TrimPrefix(c.Path(), "/"))
		path = filepath.Clean(path)
		if err == nil && filepath.IsLocal(path) {
			name := filepath.Join(directory, path)
			if info, err := os.Stat(name); err == nil && !info.IsDir() {
				return c.SendFile(name)
			}
		}
		return c.SendFile(filepath.Join(directory, "index.html"))
	}
}