package polling

import (
	"context"
	"sync"
	"time"

	"go.uber.org/zap"

	"github.com/break/junhong_cmp_fiber/internal/model"
	"github.com/break/junhong_cmp_fiber/internal/store/postgres"
	"github.com/break/junhong_cmp_fiber/pkg/errors"
)

// CleanupService 数据清理服务
type CleanupService struct {
	configStore *postgres.DataCleanupConfigStore
	logStore    *postgres.DataCleanupLogStore
	logger      *zap.Logger
	mu          sync.Mutex // 防止并发清理
	isRunning   bool
}

// NewCleanupService 创建数据清理服务实例
func NewCleanupService(
	configStore *postgres.DataCleanupConfigStore,
	logStore *postgres.DataCleanupLogStore,
	logger *zap.Logger,
) *CleanupService {
	return &CleanupService{
		configStore: configStore,
		logStore:    logStore,
		logger:      logger,
	}
}

// CreateConfig 创建清理配置
func (s *CleanupService) CreateConfig(ctx context.Context, config *model.DataCleanupConfig) error {
	if config.TargetTable == "" {
		return errors.New(errors.CodeInvalidParam, "表名不能为空")
	}
	if config.RetentionDays < 7 {
		return errors.New(errors.CodeInvalidParam, "保留天数不能少于7天")
	}
	if config.BatchSize <= 0 {
		config.BatchSize = 10000 // 默认每批1万条
	}
	config.Enabled = 1 // 默认启用
	return s.configStore.Create(ctx, config)
}

// GetConfig 获取清理配置
func (s *CleanupService) GetConfig(ctx context.Context, id uint) (*model.DataCleanupConfig, error) {
	config, err := s.configStore.GetByID(ctx, id)
	if err != nil {
		return nil, errors.Wrap(errors.CodeNotFound, err, "清理配置不存在")
	}
	return config, nil
}

// ListConfigs 获取所有清理配置
func (s *CleanupService) ListConfigs(ctx context.Context) ([]*model.DataCleanupConfig, error) {
	return s.configStore.List(ctx)
}

// UpdateConfig 更新清理配置
func (s *CleanupService) UpdateConfig(ctx context.Context, id uint, updates map[string]any) error {
	config, err := s.configStore.GetByID(ctx, id)
	if err != nil {
		return errors.Wrap(errors.CodeNotFound, err, "清理配置不存在")
	}

	if retentionDays, ok := updates["retention_days"].(int); ok {
		if retentionDays < 7 {
			return errors.New(errors.CodeInvalidParam, "保留天数不能少于7天")
		}
		config.RetentionDays = retentionDays
	}
	if batchSize, ok := updates["batch_size"].(int); ok {
		if batchSize > 0 {
			config.BatchSize = batchSize
		}
	}
	if enabled, ok := updates["enabled"].(int); ok {
		config.Enabled = int16(enabled)
	}
	if desc, ok := updates["description"].(string); ok {
		config.Description = desc
	}
	if updatedBy, ok := updates["updated_by"].(uint); ok {
		config.UpdatedBy = &updatedBy
	}

	return s.configStore.Update(ctx, config)
}

// DeleteConfig 删除清理配置
func (s *CleanupService) DeleteConfig(ctx context.Context, id uint) error {
	_, err := s.configStore.GetByID(ctx, id)
	if err != nil {
		return errors.Wrap(errors.CodeNotFound, err, "清理配置不存在")
	}
	return s.configStore.Delete(ctx, id)
}

// ListLogs 获取清理日志列表
func (s *CleanupService) ListLogs(ctx context.Context, page, pageSize int, tableName string) ([]*model.DataCleanupLog, int64, error) {
	if page < 1 {
		page = 1
	}
	if pageSize < 1 || pageSize > 100 {
		pageSize = 20
	}
	return s.logStore.List(ctx, page, pageSize, tableName)
}

// CleanupPreview 清理预览
type CleanupPreview struct {
	TableName     string `json:"table_name"`
	RetentionDays int    `json:"retention_days"`
	RecordCount   int64  `json:"record_count"`
	Description   string `json:"description"`
}

// Preview 预览待清理数据
func (s *CleanupService) Preview(ctx context.Context) ([]*CleanupPreview, error) {
	configs, err := s.configStore.ListEnabled(ctx)
	if err != nil {
		return nil, err
	}

	previews := make([]*CleanupPreview, 0, len(configs))
	for _, config := range configs {
		count, err := s.logStore.CountOldRecords(ctx, config.TargetTable, config.RetentionDays)
		if err != nil {
			s.logger.Warn("预览清理数据失败",
				zap.String("table", config.TargetTable),
				zap.Error(err))
			continue
		}

		previews = append(previews, &CleanupPreview{
			TableName:     config.TargetTable,
			RetentionDays: config.RetentionDays,
			RecordCount:   count,
			Description:   config.Description,
		})
	}

	return previews, nil
}

// CleanupProgress 清理进度
type CleanupProgress struct {
	IsRunning       bool                  `json:"is_running"`
	CurrentTable    string                `json:"current_table,omitempty"`
	TotalTables     int                   `json:"total_tables"`
	ProcessedTables int                   `json:"processed_tables"`
	TotalDeleted    int64                 `json:"total_deleted"`
	StartedAt       *time.Time            `json:"started_at,omitempty"`
	LastLog         *model.DataCleanupLog `json:"last_log,omitempty"`
}

// GetProgress 获取清理进度
func (s *CleanupService) GetProgress(ctx context.Context) (*CleanupProgress, error) {
	s.mu.Lock()
	isRunning := s.isRunning
	s.mu.Unlock()

	// 获取最近的清理日志
	logs, _, err := s.logStore.List(ctx, 1, 1, "")
	if err != nil {
		return nil, err
	}

	progress := &CleanupProgress{
		IsRunning: isRunning,
	}

	if len(logs) > 0 {
		progress.LastLog = logs[0]
		if logs[0].Status == "running" {
			progress.CurrentTable = logs[0].TargetTable
			progress.StartedAt = &logs[0].StartedAt
		}
	}

	return progress, nil
}

// TriggerCleanup 手动触发清理
func (s *CleanupService) TriggerCleanup(ctx context.Context, tableName string, triggeredBy uint) error {
	s.mu.Lock()
	if s.isRunning {
		s.mu.Unlock()
		return errors.New(errors.CodeInvalidParam, "清理任务正在运行中")
	}
	s.isRunning = true
	s.mu.Unlock()

	defer func() {
		s.mu.Lock()
		s.isRunning = false
		s.mu.Unlock()
	}()

	var configs []*model.DataCleanupConfig
	var err error

	if tableName != "" {
		// 清理指定表
		config, err := s.configStore.GetByTableName(ctx, tableName)
		if err != nil {
			return errors.Wrap(errors.CodeNotFound, err, "清理配置不存在")
		}
		configs = []*model.DataCleanupConfig{config}
	} else {
		// 清理所有启用的表
		configs, err = s.configStore.ListEnabled(ctx)
		if err != nil {
			return err
		}
	}

	for _, config := range configs {
		if err := s.cleanupTable(ctx, config, "manual", &triggeredBy); err != nil {
			s.logger.Error("清理表失败",
				zap.String("table", config.TargetTable),
				zap.Error(err))
			// 继续处理其他表
		}
	}

	return nil
}

// RunScheduledCleanup 运行定时清理任务
func (s *CleanupService) RunScheduledCleanup(ctx context.Context) error {
	s.mu.Lock()
	if s.isRunning {
		s.mu.Unlock()
		s.logger.Info("清理任务正在运行中，跳过本次调度")
		return nil
	}
	s.isRunning = true
	s.mu.Unlock()

	defer func() {
		s.mu.Lock()
		s.isRunning = false
		s.mu.Unlock()
	}()

	configs, err := s.configStore.ListEnabled(ctx)
	if err != nil {
		return err
	}

	s.logger.Info("开始定时清理任务", zap.Int("config_count", len(configs)))

	for _, config := range configs {
		if err := s.cleanupTable(ctx, config, "scheduled", nil); err != nil {
			s.logger.Error("定时清理表失败",
				zap.String("table", config.TargetTable),
				zap.Error(err))
			// 继续处理其他表
		}
	}

	s.logger.Info("定时清理任务完成")
	return nil
}

// cleanupTable 清理指定表
func (s *CleanupService) cleanupTable(ctx context.Context, config *model.DataCleanupConfig, cleanupType string, triggeredBy *uint) error {
	startTime := time.Now()

	// 创建清理日志
	log := &model.DataCleanupLog{
		TargetTable:   config.TargetTable,
		CleanupType:   cleanupType,
		RetentionDays: config.RetentionDays,
		Status:        "running",
		StartedAt:     startTime,
		TriggeredBy:   triggeredBy,
	}
	if err := s.logStore.Create(ctx, log); err != nil {
		return err
	}

	var totalDeleted int64
	var lastErr error

	// 分批删除
cleanupLoop:
	for {
		deleted, err := s.logStore.DeleteOldRecords(ctx, config.TargetTable, config.RetentionDays, config.BatchSize)
		if err != nil {
			lastErr = err
			break
		}

		totalDeleted += deleted
		s.logger.Debug("清理进度",
			zap.String("table", config.TargetTable),
			zap.Int64("batch_deleted", deleted),
			zap.Int64("total_deleted", totalDeleted))

		if deleted < int64(config.BatchSize) {
			// 没有更多数据需要删除
			break
		}

		// 检查 context 是否已取消
		select {
		case <-ctx.Done():
			lastErr = ctx.Err()
			break cleanupLoop
		default:
		}
	}

	// 更新清理日志
	endTime := time.Now()
	log.CompletedAt = &endTime
	log.DeletedCount = totalDeleted
	log.DurationMs = endTime.Sub(startTime).Milliseconds()

	if lastErr != nil {
		log.Status = "failed"
		log.ErrorMessage = lastErr.Error()
	} else {
		log.Status = "success"
	}

	if err := s.logStore.Update(ctx, log); err != nil {
		s.logger.Error("更新清理日志失败", zap.Error(err))
	}

	s.logger.Info("清理表完成",
		zap.String("table", config.TargetTable),
		zap.Int64("deleted_count", totalDeleted),
		zap.Int64("duration_ms", log.DurationMs),
		zap.String("status", log.Status))

	return lastErr
}