package config

import (
	"fmt"
	"strings"
	"time"

	"github.com/spf13/viper"
)

// Config 主配置结构体
type Config struct {
	Server            ServerConfig            `mapstructure:"server"`
	Database          DatabaseConfig          `mapstructure:"database"`
	Redis             RedisConfig             `mapstructure:"redis"`
	Cache             CacheConfig             `mapstructure:"cache"`
	S3                S3Config                `mapstructure:"s3"`
	JWT               JWTConfig               `mapstructure:"jwt"`
	Log               LogConfig               `mapstructure:"log"`
	RateLimit         RateLimitConfig         `mapstructure:"rate_limit"`
	Upload            UploadConfig            `mapstructure:"upload"`
	OpenAI            OpenAIConfig            `mapstructure:"openai"`
	TencentTMS        TencentTMSConfig        `mapstructure:"tencent_tms"`
	Email             EmailConfig             `mapstructure:"email"`
	ConversationCache ConversationCacheConfig `mapstructure:"conversation_cache"`
	GRPC              GRPCConfig              `mapstructure:"grpc"`
	Casbin            CasbinConfig            `mapstructure:"casbin"`
	Encryption        EncryptionConfig        `mapstructure:"encryption"`
	HotRank           HotRankConfig           `mapstructure:"hot_rank"`
	WebRTC            WebRTCConfig            `mapstructure:"webrtc"`
	Report            ReportConfig            `mapstructure:"report"`
	Sensitive         SensitiveConfig         `mapstructure:"sensitive"`
	JPush             JPushConfig             `mapstructure:"jpush"`
	SetupSecret       string                  `mapstructure:"setup_secret"`
}

// Load 加载配置文件
func Load(configPath string) (*Config, error) {
	viper.SetConfigFile(configPath)
	viper.SetConfigType("yaml")

	// 启用环境变量支持
	viper.SetEnvPrefix("APP")
	viper.AutomaticEnv()
	// 允许环境变量使用下划线或连字符
	viper.SetEnvKeyReplacer(strings.NewReplacer(".", "_", "-", "_"))

	// Set default values
	viper.SetDefault("server.port", 8080)
	viper.SetDefault("server.mode", "debug")
	viper.SetDefault("server.host", "0.0.0.0")
	viper.SetDefault("database.type", "sqlite")
	viper.SetDefault("database.sqlite.path", "./data/with_you.db")
	viper.SetDefault("database.max_idle_conns", 10)
	viper.SetDefault("database.max_open_conns", 100)
	viper.SetDefault("database.log_level", "warn")
	viper.SetDefault("database.slow_threshold_ms", 200)
	viper.SetDefault("database.ignore_record_not_found", true)
	viper.SetDefault("database.parameterized_queries", true)
	viper.SetDefault("redis.type", "miniredis")
	viper.SetDefault("redis.redis.host", "localhost")
	viper.SetDefault("redis.redis.port", 6379)
	viper.SetDefault("redis.redis.password", "")
	viper.SetDefault("redis.redis.db", 0)
	viper.SetDefault("redis.miniredis.host", "localhost")
	viper.SetDefault("redis.miniredis.port", 6379)
	viper.SetDefault("redis.pool_size", 10)
	viper.SetDefault("cache.enabled", true)
	viper.SetDefault("cache.key_prefix", "")
	viper.SetDefault("cache.default_ttl", 30)
	viper.SetDefault("cache.null_ttl", 5)
	viper.SetDefault("cache.jitter_ratio", 0.1)
	viper.SetDefault("cache.disable_flushdb", true)
	viper.SetDefault("cache.modules.post_list_ttl", 30)
	viper.SetDefault("cache.modules.conversation_ttl", 60)
	viper.SetDefault("cache.modules.unread_count_ttl", 30)
	viper.SetDefault("cache.modules.group_members_ttl", 120)
	viper.SetDefault("cache.local.enabled", true)
	viper.SetDefault("cache.local.size", 10000)
	viper.SetDefault("cache.local.buckets", 0)
	viper.SetDefault("cache.local.default_ttl", 300)
	viper.SetDefault("jwt.secret", "your-jwt-secret-key-change-in-production")
	viper.SetDefault("jwt.access_token_expire", 86400)
	viper.SetDefault("jwt.refresh_token_expire", 604800)
	viper.SetDefault("log.level", "info")
	viper.SetDefault("log.encoding", "json")
	viper.SetDefault("log.output_paths", []string{"stdout", "./logs/app.log"})
	viper.SetDefault("rate_limit.enabled", true)
	viper.SetDefault("rate_limit.requests_per_minute", 60)
	viper.SetDefault("upload.max_file_size", 10485760)
	viper.SetDefault("upload.allowed_types", []string{"image/jpeg", "image/png", "image/gif", "image/webp"})
	viper.SetDefault("s3.endpoint", "")
	viper.SetDefault("s3.access_key", "")
	viper.SetDefault("s3.secret_key", "")
	viper.SetDefault("s3.bucket", "")
	viper.SetDefault("s3.use_ssl", true)
	viper.SetDefault("s3.region", "us-east-1")
	viper.SetDefault("s3.domain", "")
	viper.SetDefault("sensitive.enabled", true)
	viper.SetDefault("sensitive.replace_str", "***")
	viper.SetDefault("sensitive.min_match_len", 2)
	viper.SetDefault("sensitive.load_from_db", true)
	viper.SetDefault("sensitive.load_from_redis", false)
	viper.SetDefault("sensitive.redis_key_prefix", "sensitive_words")
	viper.SetDefault("audit.enabled", false)
	viper.SetDefault("audit.provider", "local")
	viper.SetDefault("openai.enabled", true)
	viper.SetDefault("openai.base_url", "https://api.littlelan.cn/")
	viper.SetDefault("openai.api_key", "")
	viper.SetDefault("openai.moderation_model", "qwen3.5-122b")
	viper.SetDefault("openai.moderation_max_images_per_request", 1)
	viper.SetDefault("openai.request_timeout", 30)
	viper.SetDefault("openai.strict_moderation", false)
	viper.SetDefault("tencent_tms.enabled", false)
	viper.SetDefault("tencent_tms.secret_id", "")
	viper.SetDefault("tencent_tms.secret_key", "")
	viper.SetDefault("tencent_tms.region", "ap-guangzhou")
	viper.SetDefault("tencent_tms.biz_type", "")
	viper.SetDefault("tencent_tms.timeout", 30)
	viper.SetDefault("email.enabled", false)
	viper.SetDefault("email.host", "")
	viper.SetDefault("email.port", 587)
	viper.SetDefault("email.username", "")
	viper.SetDefault("email.password", "")
	viper.SetDefault("email.from_address", "")
	viper.SetDefault("email.from_name", "WithYou")
	viper.SetDefault("email.use_tls", true)
	viper.SetDefault("email.insecure_skip_verify", false)
	viper.SetDefault("email.timeout", 15)
	// ConversationCache 默认值
	viper.SetDefault("conversation_cache.detail_ttl", "5m")
	viper.SetDefault("conversation_cache.list_ttl", "60s")
	viper.SetDefault("conversation_cache.participant_ttl", "5m")
	viper.SetDefault("conversation_cache.unread_ttl", "30s")
	viper.SetDefault("conversation_cache.message_detail_ttl", "30m")
	viper.SetDefault("conversation_cache.message_list_ttl", "5m")
	viper.SetDefault("conversation_cache.message_index_ttl", "30m")
	viper.SetDefault("conversation_cache.message_count_ttl", "30m")
	viper.SetDefault("conversation_cache.batch_interval", "5s")
	viper.SetDefault("conversation_cache.batch_threshold", 100)
	viper.SetDefault("conversation_cache.batch_max_size", 500)
	viper.SetDefault("conversation_cache.buffer_max_size", 10000)
	// GRPC 默认值
	viper.SetDefault("grpc.enabled", true)
	viper.SetDefault("grpc.port", 50051)
	viper.SetDefault("grpc.tls_enabled", false)
	viper.SetDefault("grpc.tls_cert_file", "")
	viper.SetDefault("grpc.tls_key_file", "")
	viper.SetDefault("casbin.model_path", "./configs/casbin/model.conf")
	viper.SetDefault("casbin.auto_save", true)
	viper.SetDefault("casbin.auto_load", true)
	viper.SetDefault("casbin.enable_cache", true)
	viper.SetDefault("casbin.cache_ttl", 300)
	viper.SetDefault("casbin.skip_routes", []string{"/health", "/api/v1/auth/login", "/api/v1/auth/register"})
	// Encryption 默认值
	viper.SetDefault("encryption.enabled", false)
	viper.SetDefault("encryption.key", "")
	viper.SetDefault("encryption.key_version", 1)
	viper.SetDefault("hot_rank.enabled", true)
	viper.SetDefault("hot_rank.refresh_interval_seconds", 300)
	viper.SetDefault("hot_rank.top_n", 100)
	viper.SetDefault("hot_rank.recent_window_hours", 168)
	viper.SetDefault("hot_rank.recent_fetch_limit", 500)
	viper.SetDefault("hot_rank.candidate_cap", 800)
	// WebRTC 默认值（Google 公共 STUN 服务器）
	viper.SetDefault("webrtc.ice_servers", []map[string]any{
		{"urls": []string{"stun:stun.l.google.com:19302"}},
	})
	// Report 默认值
	viper.SetDefault("report.auto_hide_threshold", 3)
	viper.SetDefault("jpush.enabled", false)
	viper.SetDefault("jpush.app_key", "")
	viper.SetDefault("jpush.master_secret", "")
	viper.SetDefault("jpush.production", false)
	viper.SetDefault("setup_secret", "")

	if err := viper.ReadInConfig(); err != nil {
		return nil, fmt.Errorf("failed to read config: %w", err)
	}

	var cfg Config
	if err := viper.Unmarshal(&cfg); err != nil {
		return nil, fmt.Errorf("failed to unmarshal config: %w", err)
	}

	// Convert seconds to duration
	cfg.JWT.AccessTokenExpire = time.Duration(viper.GetInt("jwt.access_token_expire")) * time.Second
	cfg.JWT.RefreshTokenExpire = time.Duration(viper.GetInt("jwt.refresh_token_expire")) * time.Second

	// Viper AutomaticEnv 已自动处理所有 APP_ 前缀的环境变量

	// 安全检查：生产模式必须设置JWT密钥
	if cfg.Server.Mode != "debug" {
		if cfg.JWT.Secret == "" || cfg.JWT.Secret == "your-jwt-secret-key-change-in-production" {
			return nil, fmt.Errorf("SECURITY ERROR: JWT secret must be set via APP_JWT_SECRET environment variable in production mode")
		}
		if len(cfg.JWT.Secret) < 32 {
			return nil, fmt.Errorf("SECURITY ERROR: JWT secret must be at least 32 characters long in production mode")
		}
	}

	return &cfg, nil
}