package config

import (
	"context"
	"fmt"
	"os"
	"strconv"
	"strings"
	"time"

	"github.com/minio/minio-go/v7"
	"github.com/minio/minio-go/v7/pkg/credentials"
	"github.com/redis/go-redis/v9"
	"github.com/spf13/viper"
)

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"`
	Gorse     GorseConfig     `mapstructure:"gorse"`
	OpenAI    OpenAIConfig    `mapstructure:"openai"`
	Email     EmailConfig     `mapstructure:"email"`
}

type ServerConfig struct {
	Host string `mapstructure:"host"`
	Port int    `mapstructure:"port"`
	Mode string `mapstructure:"mode"`
}

type DatabaseConfig struct {
	Type                 string         `mapstructure:"type"`
	SQLite               SQLiteConfig   `mapstructure:"sqlite"`
	Postgres             PostgresConfig `mapstructure:"postgres"`
	MaxIdleConns         int            `mapstructure:"max_idle_conns"`
	MaxOpenConns         int            `mapstructure:"max_open_conns"`
	LogLevel             string         `mapstructure:"log_level"`
	SlowThresholdMs      int            `mapstructure:"slow_threshold_ms"`
	IgnoreRecordNotFound bool           `mapstructure:"ignore_record_not_found"`
	ParameterizedQueries bool           `mapstructure:"parameterized_queries"`
}

type SQLiteConfig struct {
	Path string `mapstructure:"path"`
}

type PostgresConfig struct {
	Host     string `mapstructure:"host"`
	Port     int    `mapstructure:"port"`
	User     string `mapstructure:"user"`
	Password string `mapstructure:"password"`
	DBName   string `mapstructure:"dbname"`
	SSLMode  string `mapstructure:"sslmode"`
}

func (d PostgresConfig) DSN() string {
	return fmt.Sprintf(
		"host=%s port=%d user=%s password=%s dbname=%s sslmode=%s",
		d.Host, d.Port, d.User, d.Password, d.DBName, d.SSLMode,
	)
}

type RedisConfig struct {
	Type      string            `mapstructure:"type"`
	Redis     RedisServerConfig `mapstructure:"redis"`
	Miniredis MiniredisConfig   `mapstructure:"miniredis"`
	PoolSize  int               `mapstructure:"pool_size"`
}

type CacheConfig struct {
	Enabled        bool           `mapstructure:"enabled"`
	KeyPrefix      string         `mapstructure:"key_prefix"`
	DefaultTTL     int            `mapstructure:"default_ttl"`
	NullTTL        int            `mapstructure:"null_ttl"`
	JitterRatio    float64        `mapstructure:"jitter_ratio"`
	DisableFlushDB bool           `mapstructure:"disable_flushdb"`
	Modules        CacheModuleTTL `mapstructure:"modules"`
}

type CacheModuleTTL struct {
	PostList     int `mapstructure:"post_list_ttl"`
	Conversation int `mapstructure:"conversation_ttl"`
	UnreadCount  int `mapstructure:"unread_count_ttl"`
	GroupMembers int `mapstructure:"group_members_ttl"`
}

type RedisServerConfig struct {
	Host     string `mapstructure:"host"`
	Port     int    `mapstructure:"port"`
	Password string `mapstructure:"password"`
	DB       int    `mapstructure:"db"`
}

func (r RedisServerConfig) Addr() string {
	return fmt.Sprintf("%s:%d", r.Host, r.Port)
}

type MiniredisConfig struct {
	Host string `mapstructure:"host"`
	Port int    `mapstructure:"port"`
}

type S3Config struct {
	Endpoint  string `mapstructure:"endpoint"`
	AccessKey string `mapstructure:"access_key"`
	SecretKey string `mapstructure:"secret_key"`
	Bucket    string `mapstructure:"bucket"`
	UseSSL    bool   `mapstructure:"use_ssl"`
	Region    string `mapstructure:"region"`
	Domain    string `mapstructure:"domain"` // 自定义域名，如 s3.carrot.skin
}

type JWTConfig struct {
	Secret             string        `mapstructure:"secret"`
	AccessTokenExpire  time.Duration `mapstructure:"access_token_expire"`
	RefreshTokenExpire time.Duration `mapstructure:"refresh_token_expire"`
}

type LogConfig struct {
	Level       string   `mapstructure:"level"`
	Encoding    string   `mapstructure:"encoding"`
	OutputPaths []string `mapstructure:"output_paths"`
}

type RateLimitConfig struct {
	Enabled           bool `mapstructure:"enabled"`
	RequestsPerMinute int  `mapstructure:"requests_per_minute"`
}

type UploadConfig struct {
	MaxFileSize  int64    `mapstructure:"max_file_size"`
	AllowedTypes []string `mapstructure:"allowed_types"`
}

type GorseConfig struct {
	Address         string `mapstructure:"address"`
	APIKey          string `mapstructure:"api_key"`
	Enabled         bool   `mapstructure:"enabled"`
	Dashboard       string `mapstructure:"dashboard"`
	ImportPassword  string `mapstructure:"import_password"`
	EmbeddingAPIKey string `mapstructure:"embedding_api_key"`
	EmbeddingURL    string `mapstructure:"embedding_url"`
	EmbeddingModel  string `mapstructure:"embedding_model"`
}

type OpenAIConfig struct {
	Enabled                       bool   `mapstructure:"enabled"`
	BaseURL                       string `mapstructure:"base_url"`
	APIKey                        string `mapstructure:"api_key"`
	ModerationModel               string `mapstructure:"moderation_model"`
	ModerationMaxImagesPerRequest int    `mapstructure:"moderation_max_images_per_request"`
	RequestTimeout                int    `mapstructure:"request_timeout"`
	StrictModeration              bool   `mapstructure:"strict_moderation"`
}

type EmailConfig struct {
	Enabled            bool   `mapstructure:"enabled"`
	Host               string `mapstructure:"host"`
	Port               int    `mapstructure:"port"`
	Username           string `mapstructure:"username"`
	Password           string `mapstructure:"password"`
	FromAddress        string `mapstructure:"from_address"`
	FromName           string `mapstructure:"from_name"`
	UseTLS             bool   `mapstructure:"use_tls"`
	InsecureSkipVerify bool   `mapstructure:"insecure_skip_verify"`
	Timeout            int    `mapstructure:"timeout"`
}

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/carrot_bbs.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("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("audit.enabled", false)
	viper.SetDefault("audit.provider", "local")
	viper.SetDefault("gorse.enabled", false)
	viper.SetDefault("gorse.address", "http://localhost:8087")
	viper.SetDefault("gorse.api_key", "")
	viper.SetDefault("gorse.dashboard", "http://localhost:8088")
	viper.SetDefault("gorse.import_password", "")
	viper.SetDefault("gorse.embedding_api_key", "")
	viper.SetDefault("gorse.embedding_url", "https://api.littlelan.cn/v1/embeddings")
	viper.SetDefault("gorse.embedding_model", "BAAI/bge-m3")
	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("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", "Carrot BBS")
	viper.SetDefault("email.use_tls", true)
	viper.SetDefault("email.insecure_skip_verify", false)
	viper.SetDefault("email.timeout", 15)

	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

	// 环境变量覆盖（显式处理敏感配置）
	cfg.JWT.Secret = getEnvOrDefault("APP_JWT_SECRET", cfg.JWT.Secret)
	cfg.Database.SQLite.Path = getEnvOrDefault("APP_DATABASE_SQLITE_PATH", cfg.Database.SQLite.Path)
	cfg.Database.Postgres.Host = getEnvOrDefault("APP_DATABASE_POSTGRES_HOST", cfg.Database.Postgres.Host)
	cfg.Database.Postgres.Port, _ = strconv.Atoi(getEnvOrDefault("APP_DATABASE_POSTGRES_PORT", fmt.Sprintf("%d", cfg.Database.Postgres.Port)))
	cfg.Database.Postgres.User = getEnvOrDefault("APP_DATABASE_POSTGRES_USER", cfg.Database.Postgres.User)
	cfg.Database.Postgres.Password = getEnvOrDefault("APP_DATABASE_POSTGRES_PASSWORD", cfg.Database.Postgres.Password)
	cfg.Database.Postgres.DBName = getEnvOrDefault("APP_DATABASE_POSTGRES_DBNAME", cfg.Database.Postgres.DBName)
	cfg.Database.LogLevel = getEnvOrDefault("APP_DATABASE_LOG_LEVEL", cfg.Database.LogLevel)
	cfg.Database.SlowThresholdMs, _ = strconv.Atoi(getEnvOrDefault("APP_DATABASE_SLOW_THRESHOLD_MS", fmt.Sprintf("%d", cfg.Database.SlowThresholdMs)))
	cfg.Database.IgnoreRecordNotFound, _ = strconv.ParseBool(getEnvOrDefault("APP_DATABASE_IGNORE_RECORD_NOT_FOUND", fmt.Sprintf("%t", cfg.Database.IgnoreRecordNotFound)))
	cfg.Database.ParameterizedQueries, _ = strconv.ParseBool(getEnvOrDefault("APP_DATABASE_PARAMETERIZED_QUERIES", fmt.Sprintf("%t", cfg.Database.ParameterizedQueries)))
	cfg.Redis.Redis.Host = getEnvOrDefault("APP_REDIS_REDIS_HOST", cfg.Redis.Redis.Host)
	cfg.Redis.Redis.Port, _ = strconv.Atoi(getEnvOrDefault("APP_REDIS_REDIS_PORT", fmt.Sprintf("%d", cfg.Redis.Redis.Port)))
	cfg.Redis.Redis.Password = getEnvOrDefault("APP_REDIS_REDIS_PASSWORD", cfg.Redis.Redis.Password)
	cfg.Redis.Redis.DB, _ = strconv.Atoi(getEnvOrDefault("APP_REDIS_REDIS_DB", fmt.Sprintf("%d", cfg.Redis.Redis.DB)))
	cfg.Redis.Miniredis.Host = getEnvOrDefault("APP_REDIS_MINIREDIS_HOST", cfg.Redis.Miniredis.Host)
	cfg.Redis.Miniredis.Port, _ = strconv.Atoi(getEnvOrDefault("APP_REDIS_MINIREDIS_PORT", fmt.Sprintf("%d", cfg.Redis.Miniredis.Port)))
	cfg.Redis.Type = getEnvOrDefault("APP_REDIS_TYPE", cfg.Redis.Type)
	cfg.Cache.KeyPrefix = getEnvOrDefault("APP_CACHE_KEY_PREFIX", cfg.Cache.KeyPrefix)
	cfg.Cache.Enabled, _ = strconv.ParseBool(getEnvOrDefault("APP_CACHE_ENABLED", fmt.Sprintf("%t", cfg.Cache.Enabled)))
	cfg.Cache.DisableFlushDB, _ = strconv.ParseBool(getEnvOrDefault("APP_CACHE_DISABLE_FLUSHDB", fmt.Sprintf("%t", cfg.Cache.DisableFlushDB)))
	cfg.Cache.DefaultTTL, _ = strconv.Atoi(getEnvOrDefault("APP_CACHE_DEFAULT_TTL", fmt.Sprintf("%d", cfg.Cache.DefaultTTL)))
	cfg.Cache.NullTTL, _ = strconv.Atoi(getEnvOrDefault("APP_CACHE_NULL_TTL", fmt.Sprintf("%d", cfg.Cache.NullTTL)))
	cfg.Cache.JitterRatio, _ = strconv.ParseFloat(getEnvOrDefault("APP_CACHE_JITTER_RATIO", fmt.Sprintf("%.2f", cfg.Cache.JitterRatio)), 64)
	cfg.Cache.Modules.PostList, _ = strconv.Atoi(getEnvOrDefault("APP_CACHE_MODULES_POST_LIST_TTL", fmt.Sprintf("%d", cfg.Cache.Modules.PostList)))
	cfg.Cache.Modules.Conversation, _ = strconv.Atoi(getEnvOrDefault("APP_CACHE_MODULES_CONVERSATION_TTL", fmt.Sprintf("%d", cfg.Cache.Modules.Conversation)))
	cfg.Cache.Modules.UnreadCount, _ = strconv.Atoi(getEnvOrDefault("APP_CACHE_MODULES_UNREAD_COUNT_TTL", fmt.Sprintf("%d", cfg.Cache.Modules.UnreadCount)))
	cfg.Cache.Modules.GroupMembers, _ = strconv.Atoi(getEnvOrDefault("APP_CACHE_MODULES_GROUP_MEMBERS_TTL", fmt.Sprintf("%d", cfg.Cache.Modules.GroupMembers)))
	cfg.S3.Endpoint = getEnvOrDefault("APP_S3_ENDPOINT", cfg.S3.Endpoint)
	cfg.S3.AccessKey = getEnvOrDefault("APP_S3_ACCESS_KEY", cfg.S3.AccessKey)
	cfg.S3.SecretKey = getEnvOrDefault("APP_S3_SECRET_KEY", cfg.S3.SecretKey)
	cfg.S3.Bucket = getEnvOrDefault("APP_S3_BUCKET", cfg.S3.Bucket)
	cfg.S3.Domain = getEnvOrDefault("APP_S3_DOMAIN", cfg.S3.Domain)
	cfg.Server.Host = getEnvOrDefault("APP_SERVER_HOST", cfg.Server.Host)
	cfg.Server.Port, _ = strconv.Atoi(getEnvOrDefault("APP_SERVER_PORT", fmt.Sprintf("%d", cfg.Server.Port)))
	cfg.Server.Mode = getEnvOrDefault("APP_SERVER_MODE", cfg.Server.Mode)
	cfg.Gorse.Address = getEnvOrDefault("APP_GORSE_ADDRESS", cfg.Gorse.Address)
	cfg.Gorse.APIKey = getEnvOrDefault("APP_GORSE_API_KEY", cfg.Gorse.APIKey)
	cfg.Gorse.Dashboard = getEnvOrDefault("APP_GORSE_DASHBOARD", cfg.Gorse.Dashboard)
	cfg.Gorse.ImportPassword = getEnvOrDefault("APP_GORSE_IMPORT_PASSWORD", cfg.Gorse.ImportPassword)
	cfg.Gorse.EmbeddingAPIKey = getEnvOrDefault("APP_GORSE_EMBEDDING_API_KEY", cfg.Gorse.EmbeddingAPIKey)
	cfg.Gorse.EmbeddingURL = getEnvOrDefault("APP_GORSE_EMBEDDING_URL", cfg.Gorse.EmbeddingURL)
	cfg.Gorse.EmbeddingModel = getEnvOrDefault("APP_GORSE_EMBEDDING_MODEL", cfg.Gorse.EmbeddingModel)
	cfg.OpenAI.BaseURL = getEnvOrDefault("APP_OPENAI_BASE_URL", cfg.OpenAI.BaseURL)
	cfg.OpenAI.APIKey = getEnvOrDefault("APP_OPENAI_API_KEY", cfg.OpenAI.APIKey)
	cfg.OpenAI.ModerationModel = getEnvOrDefault("APP_OPENAI_MODERATION_MODEL", cfg.OpenAI.ModerationModel)
	cfg.OpenAI.ModerationMaxImagesPerRequest, _ = strconv.Atoi(getEnvOrDefault("APP_OPENAI_MODERATION_MAX_IMAGES_PER_REQUEST", fmt.Sprintf("%d", cfg.OpenAI.ModerationMaxImagesPerRequest)))
	cfg.OpenAI.RequestTimeout, _ = strconv.Atoi(getEnvOrDefault("APP_OPENAI_REQUEST_TIMEOUT", fmt.Sprintf("%d", cfg.OpenAI.RequestTimeout)))
	cfg.OpenAI.Enabled, _ = strconv.ParseBool(getEnvOrDefault("APP_OPENAI_ENABLED", fmt.Sprintf("%t", cfg.OpenAI.Enabled)))
	cfg.OpenAI.StrictModeration, _ = strconv.ParseBool(getEnvOrDefault("APP_OPENAI_STRICT_MODERATION", fmt.Sprintf("%t", cfg.OpenAI.StrictModeration)))
	cfg.Email.Enabled, _ = strconv.ParseBool(getEnvOrDefault("APP_EMAIL_ENABLED", fmt.Sprintf("%t", cfg.Email.Enabled)))
	cfg.Email.Host = getEnvOrDefault("APP_EMAIL_HOST", cfg.Email.Host)
	cfg.Email.Port, _ = strconv.Atoi(getEnvOrDefault("APP_EMAIL_PORT", fmt.Sprintf("%d", cfg.Email.Port)))
	cfg.Email.Username = getEnvOrDefault("APP_EMAIL_USERNAME", cfg.Email.Username)
	cfg.Email.Password = getEnvOrDefault("APP_EMAIL_PASSWORD", cfg.Email.Password)
	cfg.Email.FromAddress = getEnvOrDefault("APP_EMAIL_FROM_ADDRESS", cfg.Email.FromAddress)
	cfg.Email.FromName = getEnvOrDefault("APP_EMAIL_FROM_NAME", cfg.Email.FromName)
	cfg.Email.UseTLS, _ = strconv.ParseBool(getEnvOrDefault("APP_EMAIL_USE_TLS", fmt.Sprintf("%t", cfg.Email.UseTLS)))
	cfg.Email.InsecureSkipVerify, _ = strconv.ParseBool(getEnvOrDefault("APP_EMAIL_INSECURE_SKIP_VERIFY", fmt.Sprintf("%t", cfg.Email.InsecureSkipVerify)))
	cfg.Email.Timeout, _ = strconv.Atoi(getEnvOrDefault("APP_EMAIL_TIMEOUT", fmt.Sprintf("%d", cfg.Email.Timeout)))

	return &cfg, nil
}

// getEnvOrDefault 获取环境变量值，如果未设置则返回默认值
func getEnvOrDefault(key, defaultValue string) string {
	if value := os.Getenv(key); value != "" {
		return value
	}
	return defaultValue
}

// NewRedis 创建Redis客户端（真实Redis）
func NewRedis(cfg *RedisConfig) (*redis.Client, error) {
	client := redis.NewClient(&redis.Options{
		Addr:     cfg.Redis.Addr(),
		Password: cfg.Redis.Password,
		DB:       cfg.Redis.DB,
		PoolSize: cfg.PoolSize,
	})

	ctx := context.Background()
	if err := client.Ping(ctx).Err(); err != nil {
		return nil, fmt.Errorf("failed to connect to redis: %w", err)
	}

	return client, nil
}

// NewS3 创建S3客户端
func NewS3(cfg *S3Config) (*minio.Client, error) {
	ctx, cancel := context.WithTimeout(context.Background(), time.Second*10)
	defer cancel()

	client, err := minio.New(cfg.Endpoint, &minio.Options{
		Creds:  credentials.NewStaticV4(cfg.AccessKey, cfg.SecretKey, ""),
		Secure: cfg.UseSSL,
	})
	if err != nil {
		return nil, fmt.Errorf("failed to create S3 client: %w", err)
	}

	exists, err := client.BucketExists(ctx, cfg.Bucket)
	if err != nil {
		return nil, fmt.Errorf("failed to check bucket: %w", err)
	}

	if !exists {
		if err := client.MakeBucket(ctx, cfg.Bucket, minio.MakeBucketOptions{
			Region: cfg.Region,
		}); err != nil {
			return nil, fmt.Errorf("failed to create bucket: %w", err)
		}
	}

	return client, nil
}