package task

import (
	"context"
	"encoding/json"
	"fmt"
	"log"
	"sync"
	"time"

	"github.com/redis/go-redis/v9"
	"gorm.io/gorm"

	"spider/internal/model"
	"spider/internal/notification"
	"spider/internal/plugin"
	"spider/internal/processor"
	proxypool "spider/internal/proxy"
	"spider/internal/store"
)

// StartRequest is the payload for starting a new task.
type StartRequest struct {
	PluginName       string `json:"plugin_name" binding:"required"`
	AutoClean        *bool  `json:"auto_clean"`                       // run processor after collection (default true)
	TargetGroup      string `json:"target_group,omitempty"`           // target a specific TG group/channel for collection
	ProxyID          *uint  `json:"proxy_id,omitempty"`               // optional single proxy for this task
	ProxyMode        string `json:"proxy_mode,omitempty"`             // "single" (default) or "pool"
	MaxMerchants     int    `json:"max_merchants,omitempty"`          // stop after collecting this many merchants (0 = unlimited)
	MaxDurationMins  int    `json:"max_duration_mins,omitempty"`      // stop after this many minutes (0 = unlimited)
	ResumeSnapshot   bool   `json:"resume_snapshot,omitempty"`        // resume from last snapshot
}

// Manager manages plugin task lifecycle using goroutines.
// Replaces the asynq-based worker.
type Manager struct {
	db        *gorm.DB
	redis     *redis.Client
	registry  *plugin.Registry
	store     *store.Store
	processor *processor.Processor

	mu        sync.Mutex
	running   map[uint]context.CancelFunc // taskID -> cancel
	notifier  *notification.Manager
	proxyPool *proxypool.Pool // current active proxy pool (nil when not using pool mode)
}

// NewManager creates a new task manager.
func NewManager(db *gorm.DB, rdb *redis.Client, reg *plugin.Registry, s *store.Store, proc *processor.Processor) *Manager {
	return &Manager{
		db:        db,
		redis:     rdb,
		registry:  reg,
		store:     s,
		processor: proc,
		running:   make(map[uint]context.CancelFunc),
	}
}

// StartTask validates, creates a TaskLog record, and runs the plugin in a goroutine.
func (m *Manager) StartTask(req StartRequest) (*model.TaskLog, error) {
	// Validate plugin exists
	collector, err := m.registry.Get(req.PluginName)
	if err != nil {
		return nil, fmt.Errorf("unknown plugin: %s", req.PluginName)
	}

	// Check if same plugin is already running
	var count int64
	m.db.Model(&model.TaskLog{}).
		Where("plugin_name = ? AND status = ?", req.PluginName, "running").
		Count(&count)
	if count > 0 {
		return nil, fmt.Errorf("plugin %s is already running", req.PluginName)
	}

	// Resolve proxy configuration
	var proxyID *uint
	var proxyName string
	var proxyURL string
	var pool *proxypool.Pool

	if req.ProxyMode == "pool" {
		// Pool mode: load all enabled proxies
		var proxies []model.Proxy
		m.db.Where("enabled = ?", true).Find(&proxies)
		if len(proxies) == 0 {
			return nil, fmt.Errorf("代理池模式但没有可用的代理")
		}
		pool = proxypool.NewPool(3, 2*time.Minute)
		names := make([]string, 0, len(proxies))
		for _, p := range proxies {
			pool.Add(p.ID, p.Name, p.ProxyURL(), p.Region)
			names = append(names, p.Name)
		}
		proxyName = fmt.Sprintf("代理池(%d个)", len(proxies))
		m.mu.Lock()
		m.proxyPool = pool
		m.mu.Unlock()
		log.Printf("[task] using proxy pool with %d proxies: %v", len(proxies), names)
	} else if req.ProxyID != nil && *req.ProxyID > 0 {
		// Single proxy mode
		var proxy model.Proxy
		if err := m.db.First(&proxy, *req.ProxyID).Error; err == nil {
			proxyID = &proxy.ID
			proxyName = proxy.Name
			proxyURL = proxy.ProxyURL()
		}
	}

	// Create task log record
	now := time.Now()
	taskLog := &model.TaskLog{
		TaskType:   "collect",
		PluginName: req.PluginName,
		Status:     "running",
		StartedAt:  &now,
		ProxyID:    proxyID,
		ProxyName:  proxyName,
		ProxyMode:  req.ProxyMode,
	}
	if err := m.db.Create(taskLog).Error; err != nil {
		return nil, fmt.Errorf("create task log: %w", err)
	}

	// Build config for the plugin
	cfg, err := m.buildPluginConfig(req.PluginName)
	if err != nil {
		m.failTask(taskLog, err)
		return nil, err
	}
	// Set proxy in config
	if pool != nil {
		cfg["proxy_pool"] = pool
		// Also set an initial proxy_url for compatibility
		cfg["proxy_url"] = pool.Next()
	} else if proxyURL != "" {
		cfg["proxy_url"] = proxyURL
	}

	// Stop conditions
	if req.MaxMerchants > 0 {
		cfg["max_merchants"] = req.MaxMerchants
	}
	if req.MaxDurationMins > 0 {
		cfg["max_duration_mins"] = req.MaxDurationMins
	}
	cfg["resume_snapshot"] = req.ResumeSnapshot

	// If targeting a specific group, override seeds config
	if req.TargetGroup != "" {
		cfg["seeds"] = []string{req.TargetGroup}
		cfg["target_group"] = req.TargetGroup
		cfg["max_depth"] = 0     // don't BFS discover, just scrape this group
		cfg["max_channels"] = 1
	}

	// Start in goroutine
	ctx, cancel := context.WithCancel(context.Background())

	m.mu.Lock()
	m.running[taskLog.ID] = cancel
	m.mu.Unlock()

	// Default to true if not explicitly set
	autoClean := req.AutoClean == nil || *req.AutoClean

	go m.runTask(ctx, taskLog, collector, cfg, autoClean)

	return taskLog, nil
}

func (m *Manager) runTask(ctx context.Context, taskLog *model.TaskLog, collector plugin.Collector, cfg map[string]any, autoClean bool) {
	defer func() {
		m.mu.Lock()
		delete(m.running, taskLog.ID)
		m.proxyPool = nil // clear stale pool reference
		m.mu.Unlock()
	}()

	// Recover from panics to prevent crashing the entire server
	defer func() {
		if r := recover(); r != nil {
			log.Printf("[task] PANIC in task %d: %v", taskLog.ID, r)
			finishedAt := time.Now()
			m.db.Model(taskLog).Updates(map[string]any{
				"status":      "failed",
				"finished_at": &finishedAt,
				"detail":      fmt.Sprintf("panic: %v", r),
			})
		}
	}()

	// Create detail logger for this task
	dl := NewDetailLogger(m.db, taskLog.ID)
	defer dl.Close()
	collector.SetLogger(dl)

	m.writeLog(ctx, taskLog.ID, fmt.Sprintf("开始采集: %s", collector.Name()))

	merchantCount := 0
	errCount := 0

	// Callback: for each merchant found, save to raw table + group-member relationship
	callback := func(data plugin.MerchantData) {
		inserted, err := m.store.SaveRaw(data)
		if err != nil {
			errCount++
			log.Printf("[task] save raw error: %v", err)
			return
		}
		// Record group-member relationship if source is a TG group/channel
		if data.GroupUsername != "" && data.TgUsername != "" {
			m.store.SaveGroupMember(data.GroupUsername, data.TgUsername, data.GroupTitle, data.SourceType, taskLog.ID)
		}
		if inserted {
			merchantCount++
			if merchantCount%10 == 0 {
				m.writeProgress(ctx, taskLog.ID, collector.Name(), merchantCount, 0,
					fmt.Sprintf("已采集 %d 个商户", merchantCount))
			}
		}
	}

	// Run the collector
	runErr := collector.Run(ctx, cfg, callback)

	// Check if stopped
	if m.isStopRequested(ctx, taskLog.ID) || ctx.Err() != nil {
		m.writeLog(ctx, taskLog.ID, "任务已停止")
		finishedAt := time.Now()
		m.db.Model(taskLog).Updates(map[string]any{
			"status":          "stopped",
			"finished_at":     &finishedAt,
			"merchants_added": merchantCount,
			"errors_count":    errCount,
		})
		return
	}

	if runErr != nil {
		m.failTask(taskLog, runErr)
		m.writeLog(ctx, taskLog.ID, "采集失败: "+runErr.Error())
		m.notify("task_failed", "任务失败", fmt.Sprintf("采集任务 #%d (%s) 失败: %s", taskLog.ID, collector.Name(), runErr.Error()))
		return
	}

	m.writeLog(ctx, taskLog.ID, fmt.Sprintf("采集完成: 新增 %d 个商户", merchantCount))

	// Auto-clean: run processor if there are any unprocessed raw records
	var pendingRaw int64
	m.db.Model(&model.MerchantRaw{}).Where("status = ?", "raw").Count(&pendingRaw)
	if autoClean && pendingRaw > 0 {
		m.writeLog(ctx, taskLog.ID, "开始清洗流程...")
		m.writeProgress(ctx, taskLog.ID, "clean", 0, 0, "清洗中...")

		m.processor.SetProgressFn(func(step string, current, total int, msg string) {
			m.writeProgress(ctx, taskLog.ID, step, current, total, msg)
			m.writeLog(ctx, taskLog.ID, fmt.Sprintf("[%s] %d/%d %s", step, current, total, msg))
		})
		m.processor.SetLogger(dl)

		procResult, procErr := m.processor.Process(ctx)
		if procErr != nil {
			m.writeLog(ctx, taskLog.ID, "清洗失败: "+procErr.Error())
		} else {
			m.writeLog(ctx, taskLog.ID, fmt.Sprintf("清洗完成: Hot=%d, Warm=%d, Cold=%d",
				procResult.HotCount, procResult.WarmCount, procResult.ColdCount))
		}
	}

	// Complete
	finishedAt := time.Now()
	detail := fmt.Sprintf("采集 %d 个商户, 错误 %d 次", merchantCount, errCount)
	if pool, ok := cfg["proxy_pool"].(*proxypool.Pool); ok && pool != nil {
		detail += " | " + pool.Summary()
	}
	m.db.Model(taskLog).Updates(map[string]any{
		"status":          "completed",
		"finished_at":     &finishedAt,
		"merchants_added": merchantCount,
		"errors_count":    errCount,
		"detail":          detail,
	})

	m.writeProgress(ctx, taskLog.ID, "done", 100, 100, "任务完成")
	m.writeLog(ctx, taskLog.ID, "任务完成")
	log.Printf("[task] task %d completed: %s", taskLog.ID, detail)
	m.notify("task_completed", "任务完成", fmt.Sprintf("采集任务 #%d (%s): %s", taskLog.ID, collector.Name(), detail))
}

// StartClean runs the processor independently (not tied to a plugin).
func (m *Manager) StartClean() (*model.TaskLog, error) {
	var count int64
	m.db.Model(&model.TaskLog{}).
		Where("task_type = ? AND status = ?", "clean", "running").
		Count(&count)
	if count > 0 {
		return nil, fmt.Errorf("clean task is already running")
	}

	now := time.Now()
	taskLog := &model.TaskLog{
		TaskType:   "clean",
		PluginName: "",
		Status:     "running",
		StartedAt:  &now,
	}
	if err := m.db.Create(taskLog).Error; err != nil {
		return nil, err
	}

	ctx, cancel := context.WithCancel(context.Background())
	m.mu.Lock()
	m.running[taskLog.ID] = cancel
	m.mu.Unlock()

	go func() {
		defer func() {
			m.mu.Lock()
			delete(m.running, taskLog.ID)
			m.mu.Unlock()
		}()

		defer func() {
			if r := recover(); r != nil {
				log.Printf("[task] PANIC in clean task %d: %v", taskLog.ID, r)
				finishedAt := time.Now()
				m.db.Model(taskLog).Updates(map[string]any{
					"status":      "failed",
					"finished_at": &finishedAt,
					"detail":      fmt.Sprintf("panic: %v", r),
				})
			}
		}()

		m.writeLog(ctx, taskLog.ID, "开始独立清洗任务")

		m.processor.SetProgressFn(func(step string, current, total int, msg string) {
			m.writeProgress(ctx, taskLog.ID, step, current, total, msg)
		})

		result, err := m.processor.Process(ctx)

		finishedAt := time.Now()
		if err != nil {
			m.db.Model(taskLog).Updates(map[string]any{
				"status":      "failed",
				"finished_at": &finishedAt,
				"detail":      err.Error(),
			})
			m.notify("task_failed", "清洗任务失败", fmt.Sprintf("清洗任务 #%d 失败: %s", taskLog.ID, err.Error()))
			return
		}

		detail := fmt.Sprintf("输入 %d, Hot=%d, Warm=%d, Cold=%d",
			result.InputCount, result.HotCount, result.WarmCount, result.ColdCount)
		m.db.Model(taskLog).Updates(map[string]any{
			"status":          "completed",
			"finished_at":     &finishedAt,
			"items_processed": result.InputCount,
			"merchants_added": result.OutputCount,
			"detail":          detail,
		})

		m.writeLog(ctx, taskLog.ID, "清洗完成: "+detail)
		m.notify("task_completed", "清洗任务完成", fmt.Sprintf("清洗任务 #%d: %s", taskLog.ID, detail))

		// Notify for new hot merchants
		if result.HotCount > 0 {
			m.notify("new_hot_merchant", "发现优质商户", fmt.Sprintf("清洗任务 #%d 发现 %d 个优质商户", taskLog.ID, result.HotCount))
		}
	}()

	return taskLog, nil
}

// StopAll cancels all running tasks (used during graceful shutdown).
func (m *Manager) StopAll() {
	m.mu.Lock()
	running := make(map[uint]context.CancelFunc, len(m.running))
	for id, cancel := range m.running {
		running[id] = cancel
	}
	m.mu.Unlock()

	for id, cancel := range running {
		log.Printf("[task] stopping task %d for shutdown", id)
		cancel()

		finishedAt := time.Now()
		m.db.Model(&model.TaskLog{}).Where("id = ? AND status = ?", id, "running").
			Updates(map[string]any{
				"status":      "stopped",
				"finished_at": &finishedAt,
				"detail":      "服务关闭，任务停止",
			})
	}

	// Clear proxy pool reference
	m.mu.Lock()
	m.proxyPool = nil
	m.mu.Unlock()
}

// StopTask cancels a running task.
func (m *Manager) StopTask(taskID uint) error {
	// Set Redis stop signal
	key := fmt.Sprintf("spider:task:stop:%d", taskID)
	m.redis.Set(context.Background(), key, "1", time.Hour)

	// Cancel the goroutine context
	m.mu.Lock()
	cancel, ok := m.running[taskID]
	m.mu.Unlock()

	if ok {
		cancel()
	}

	// Also try to stop the collector
	var taskLog model.TaskLog
	if err := m.db.First(&taskLog, taskID).Error; err == nil && taskLog.PluginName != "" {
		if collector, err := m.registry.Get(taskLog.PluginName); err == nil {
			collector.Stop()
		}
	}

	return nil
}

// GetProgress reads live progress from Redis.
func (m *Manager) GetProgress(taskID uint) map[string]any {
	key := fmt.Sprintf("spider:task:progress:%d", taskID)
	vals, err := m.redis.HGetAll(context.Background(), key).Result()
	if err != nil {
		return nil
	}
	result := make(map[string]any)
	for k, v := range vals {
		result[k] = v
	}
	return result
}

// GetLogs reads task logs from Redis.
func (m *Manager) GetLogs(taskID uint) []string {
	key := fmt.Sprintf("spider:task:logs:%d", taskID)
	logs, err := m.redis.LRange(context.Background(), key, 0, -1).Result()
	if err != nil {
		return nil
	}
	return logs
}

// buildPluginConfig builds the config map for a plugin from the DB.
func (m *Manager) buildPluginConfig(pluginName string) (map[string]any, error) {
	cfg := make(map[string]any)

	switch pluginName {
	case "web_collector":
		keywords, err := m.store.ListEnabledKeywords()
		if err != nil {
			return nil, err
		}
		kws := make([]string, 0, len(keywords))
		for _, k := range keywords {
			kws = append(kws, k.Keyword)
		}
		cfg["keywords"] = kws

	case "tg_collector":
		seeds, err := m.store.ListSeeds()
		if err != nil {
			return nil, err
		}
		seedNames := make([]string, 0, len(seeds))
		for _, s := range seeds {
			seedNames = append(seedNames, s.Keyword)
		}
		cfg["seeds"] = seedNames
		cfg["max_depth"] = 3
		cfg["max_channels"] = 500
		cfg["message_limit"] = 500

	case "github_collector":
		keywords, err := m.store.ListEnabledKeywords()
		if err != nil {
			return nil, err
		}
		kws := make([]string, 0, len(keywords))
		for _, k := range keywords {
			kws = append(kws, k.Keyword)
		}
		cfg["keywords"] = kws
		cfg["repos_limit"] = 50
	}

	return cfg, nil
}

func (m *Manager) failTask(taskLog *model.TaskLog, err error) {
	finishedAt := time.Now()
	m.db.Model(taskLog).Updates(map[string]any{
		"status":      "failed",
		"finished_at": &finishedAt,
		"detail":      err.Error(),
	})
}

func (m *Manager) isStopRequested(ctx context.Context, taskID uint) bool {
	key := fmt.Sprintf("spider:task:stop:%d", taskID)
	val, _ := m.redis.Get(ctx, key).Result()
	return val == "1"
}

// TaskPubSubChannel returns the Redis Pub/Sub channel name for a task.
func TaskPubSubChannel(taskID uint) string {
	return fmt.Sprintf("spider:task:events:%d", taskID)
}

func (m *Manager) writeLog(ctx context.Context, taskID uint, msg string) {
	key := fmt.Sprintf("spider:task:logs:%d", taskID)
	ts := time.Now().Format("15:04:05")
	line := fmt.Sprintf("[%s] %s", ts, msg)
	m.redis.RPush(ctx, key, line)
	m.redis.LTrim(ctx, key, -500, -1)
	m.redis.Expire(ctx, key, 24*time.Hour)

	// Publish to Pub/Sub for real-time WebSocket delivery
	m.redis.Publish(ctx, TaskPubSubChannel(taskID), line)
}

func (m *Manager) writeProgress(ctx context.Context, taskID uint, phase string, current, total int, message string) {
	key := fmt.Sprintf("spider:task:progress:%d", taskID)
	now := time.Now().UTC().Format(time.RFC3339)
	fields := map[string]any{
		"phase":      phase,
		"current":    current,
		"total":      total,
		"message":    message,
		"updated_at": now,
	}
	b, _ := json.Marshal(fields)
	m.redis.Set(ctx, key, string(b), 24*time.Hour)

	// Publish progress to Pub/Sub
	m.redis.Publish(ctx, TaskPubSubChannel(taskID), fmt.Sprintf("[进度] %s", message))
}

// GetProxyPool returns the current active proxy pool (may be nil).
func (m *Manager) GetProxyPool() *proxypool.Pool {
	m.mu.Lock()
	defer m.mu.Unlock()
	return m.proxyPool
}

// GetRedis returns the Redis client for WebSocket Pub/Sub subscription.
func (m *Manager) GetRedis() *redis.Client {
	return m.redis
}

// SetNotifier sets the notification manager for event dispatching.
func (m *Manager) SetNotifier(n *notification.Manager) {
	m.notifier = n
}

func (m *Manager) notify(eventType, title, msg string) {
	if m.notifier == nil {
		return
	}
	m.notifier.Send(notification.Event{
		Type:    eventType,
		Title:   title,
		Message: msg,
	})
}

// ListPlugins returns all registered plugin names.
func (m *Manager) ListPlugins() []string {
	return m.registry.List()
}