package cache

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

	"github.com/redis/go-redis/v9"
	"go.uber.org/zap"

	"tyapi-server/internal/shared/interfaces"
)

// RedisCache Redis缓存实现
type RedisCache struct {
	client *redis.Client
	logger *zap.Logger
	prefix string

	// 统计信息
	hits   int64
	misses int64
}

// NewRedisCache 创建Redis缓存实例
func NewRedisCache(client *redis.Client, logger *zap.Logger, prefix string) *RedisCache {
	return &RedisCache{
		client: client,
		logger: logger,
		prefix: prefix,
	}
}

// Name 返回服务名称
func (r *RedisCache) Name() string {
	return "redis-cache"
}

// Initialize 初始化服务
func (r *RedisCache) Initialize(ctx context.Context) error {
	// 测试连接
	_, err := r.client.Ping(ctx).Result()
	if err != nil {
		r.logger.Error("Failed to connect to Redis", zap.Error(err))
		return fmt.Errorf("redis connection failed: %w", err)
	}

	r.logger.Info("Redis cache service initialized")
	return nil
}

// HealthCheck 健康检查
func (r *RedisCache) HealthCheck(ctx context.Context) error {
	_, err := r.client.Ping(ctx).Result()
	return err
}

// Shutdown 关闭服务
func (r *RedisCache) Shutdown(ctx context.Context) error {
	return r.client.Close()
}

// Get 获取缓存值
func (r *RedisCache) Get(ctx context.Context, key string, dest interface{}) error {
	fullKey := r.getFullKey(key)

	val, err := r.client.Get(ctx, fullKey).Result()
	if err != nil {
		if err == redis.Nil {
			r.misses++
			return fmt.Errorf("cache miss: key %s not found", key)
		}
		r.logger.Error("Failed to get cache", zap.String("key", key), zap.Error(err))
		return err
	}

	r.hits++
	return json.Unmarshal([]byte(val), dest)
}

// Set 设置缓存值
func (r *RedisCache) Set(ctx context.Context, key string, value interface{}, ttl ...interface{}) error {
	fullKey := r.getFullKey(key)

	data, err := json.Marshal(value)
	if err != nil {
		return fmt.Errorf("failed to marshal value: %w", err)
	}

	var expiration time.Duration
	if len(ttl) > 0 {
		switch v := ttl[0].(type) {
		case time.Duration:
			expiration = v
		case int:
			expiration = time.Duration(v) * time.Second
		case string:
			expiration, _ = time.ParseDuration(v)
		default:
			expiration = 24 * time.Hour // 默认24小时
		}
	} else {
		expiration = 24 * time.Hour // 默认24小时
	}

	err = r.client.Set(ctx, fullKey, data, expiration).Err()
	if err != nil {
		r.logger.Error("Failed to set cache", zap.String("key", key), zap.Error(err))
		return err
	}

	return nil
}

// Delete 删除缓存
func (r *RedisCache) Delete(ctx context.Context, keys ...string) error {
	if len(keys) == 0 {
		return nil
	}

	fullKeys := make([]string, len(keys))
	for i, key := range keys {
		fullKeys[i] = r.getFullKey(key)
	}

	err := r.client.Del(ctx, fullKeys...).Err()
	if err != nil {
		r.logger.Error("Failed to delete cache", zap.Strings("keys", keys), zap.Error(err))
		return err
	}

	return nil
}

// Exists 检查键是否存在
func (r *RedisCache) Exists(ctx context.Context, key string) (bool, error) {
	fullKey := r.getFullKey(key)

	count, err := r.client.Exists(ctx, fullKey).Result()
	if err != nil {
		return false, err
	}

	return count > 0, nil
}

// GetMultiple 批量获取
func (r *RedisCache) GetMultiple(ctx context.Context, keys []string) (map[string]interface{}, error) {
	if len(keys) == 0 {
		return make(map[string]interface{}), nil
	}

	fullKeys := make([]string, len(keys))
	for i, key := range keys {
		fullKeys[i] = r.getFullKey(key)
	}

	values, err := r.client.MGet(ctx, fullKeys...).Result()
	if err != nil {
		return nil, err
	}

	result := make(map[string]interface{})
	for i, val := range values {
		if val != nil {
			var data interface{}
			if err := json.Unmarshal([]byte(val.(string)), &data); err == nil {
				result[keys[i]] = data
			}
		}
	}

	return result, nil
}

// SetMultiple 批量设置
func (r *RedisCache) SetMultiple(ctx context.Context, data map[string]interface{}, ttl ...interface{}) error {
	if len(data) == 0 {
		return nil
	}

	var expiration time.Duration
	if len(ttl) > 0 {
		switch v := ttl[0].(type) {
		case time.Duration:
			expiration = v
		case int:
			expiration = time.Duration(v) * time.Second
		default:
			expiration = 24 * time.Hour
		}
	} else {
		expiration = 24 * time.Hour
	}

	pipe := r.client.Pipeline()
	for key, value := range data {
		fullKey := r.getFullKey(key)
		jsonData, err := json.Marshal(value)
		if err != nil {
			continue
		}
		pipe.Set(ctx, fullKey, jsonData, expiration)
	}

	_, err := pipe.Exec(ctx)
	return err
}

// DeletePattern 按模式删除
func (r *RedisCache) DeletePattern(ctx context.Context, pattern string) error {
	fullPattern := r.getFullKey(pattern)

	keys, err := r.client.Keys(ctx, fullPattern).Result()
	if err != nil {
		return err
	}

	if len(keys) > 0 {
		return r.client.Del(ctx, keys...).Err()
	}

	return nil
}

// Keys 获取匹配的键
func (r *RedisCache) Keys(ctx context.Context, pattern string) ([]string, error) {
	fullPattern := r.getFullKey(pattern)

	keys, err := r.client.Keys(ctx, fullPattern).Result()
	if err != nil {
		return nil, err
	}

	// 移除前缀
	result := make([]string, len(keys))
	prefixLen := len(r.prefix) + 1 // +1 for ":"
	for i, key := range keys {
		if len(key) > prefixLen {
			result[i] = key[prefixLen:]
		} else {
			result[i] = key
		}
	}

	return result, nil
}

// Stats 获取缓存统计
func (r *RedisCache) Stats(ctx context.Context) (interfaces.CacheStats, error) {
	dbSize, _ := r.client.DBSize(ctx).Result()

	return interfaces.CacheStats{
		Hits:        r.hits,
		Misses:      r.misses,
		Keys:        dbSize,
		Memory:      0, // 暂时设为0，后续可解析Redis info
		Connections: 0, // 暂时设为0，后续可解析Redis info
	}, nil
}

// getFullKey 获取完整键名
func (r *RedisCache) getFullKey(key string) string {
	if r.prefix == "" {
		return key
	}
	return fmt.Sprintf("%s:%s", r.prefix, key)
}

// Flush 清空所有缓存
func (r *RedisCache) Flush(ctx context.Context) error {
	if r.prefix == "" {
		return r.client.FlushDB(ctx).Err()
	}

	// 只删除带前缀的键
	return r.DeletePattern(ctx, "*")
}

// GetClient 获取原始Redis客户端
func (r *RedisCache) GetClient() *redis.Client {
	return r.client
}