package config

import (
	"fmt"
	"os"
	"strings"
	"time"

	"github.com/spf13/viper"
)

type Config struct {
	Server        ServerConfig
	CORS          CORSConfig
	Postgres      PostgresConfig
	Redis         RedisConfig
	Log           LogConfig
	Auth          AuthConfig
	ModelRegistry ModelRegistryConfig
	Quota         QuotaConfig
	Internal      InternalConfig
	SyncOutbox    SyncOutboxConfig
	TokenRefresh  TokenRefreshConfig
}

type ServerConfig struct {
	Port        string
	SwaggerHost string // Swagger UI 显示的 Host (可选，留空则使用相对路径)
}

type CORSConfig struct {
	AllowOrigins []string
}

type AuthConfig struct {
	JWTSecret string
}

type PostgresConfig struct {
	DSN string
}

type RedisConfig struct {
	Addr     string
	Password string
	DB       int
}

type LogConfig struct {
	BatchSize     int
	FlushInterval time.Duration
	QueueCapacity int
	RetentionDays int
	MaxRecords    int
	DSN           string
	Partitioning  string
}

type ModelRegistryConfig struct {
	Enabled             bool
	RefreshSeconds      int
	ModelsDevBaseURL    string
	ModelsDevAPIBaseURL string
	ModelsDevRef        string
	CacheDir            string
	TimeoutSeconds      int
}

type QuotaConfig struct {
	ResetIntervalSeconds int
}

type InternalConfig struct {
	StatsToken     string
	AllowAnonymous bool
}

type SyncOutboxConfig struct {
	Enabled         bool
	IntervalSeconds int
	BatchSize       int
	MaxRetries      int
}

type TokenRefreshConfig struct {
	IntervalSeconds    int
	RefreshSkewSeconds int
	BatchSize          int
	MaxRetries         int
}

func Load() (*Config, error) {
	v := viper.New()

	v.SetDefault("server.port", "8080")
	v.SetDefault("server.swagger_host", "")
	v.SetDefault("cors.allow_origins", "*")
	v.SetDefault("postgres.dsn", "host=localhost user=postgres password=postgres dbname=ezapi port=5432 sslmode=disable")
	v.SetDefault("redis.addr", "localhost:6379")
	v.SetDefault("redis.password", "")
	v.SetDefault("redis.db", 0)
	v.SetDefault("log.batch_size", 10)
	v.SetDefault("log.flush_ms", 1000)
	v.SetDefault("log.queue_capacity", 10000)
	v.SetDefault("log.retention_days", 30)
	v.SetDefault("log.max_records", 1000000)
	v.SetDefault("log.dsn", "")
	v.SetDefault("log.partitioning", "off")
	v.SetDefault("auth.jwt_secret", "change_me_in_production")
	v.SetDefault("model_registry.enabled", false)
	v.SetDefault("model_registry.refresh_seconds", 1800)
	v.SetDefault("model_registry.models_dev_base_url", "https://codeload.github.com/sst/models.dev/tar.gz")
	v.SetDefault("model_registry.models_dev_api_base_url", "https://api.github.com")
	v.SetDefault("model_registry.models_dev_ref", "dev")
	v.SetDefault("model_registry.cache_dir", "./data/model-registry")
	v.SetDefault("model_registry.timeout_seconds", 30)
	v.SetDefault("quota.reset_interval_seconds", 300)
	v.SetDefault("internal.stats_token", "")
	v.SetDefault("internal.allow_anonymous", false)
	v.SetDefault("sync_outbox.enabled", true)
	v.SetDefault("sync_outbox.interval_seconds", 5)
	v.SetDefault("sync_outbox.batch_size", 200)
	v.SetDefault("sync_outbox.max_retries", 10)
	v.SetDefault("token_refresh.interval_seconds", 1800)
	v.SetDefault("token_refresh.refresh_skew_seconds", 3000)
	v.SetDefault("token_refresh.batch_size", 200)
	v.SetDefault("token_refresh.max_retries", 3)

	v.SetEnvKeyReplacer(strings.NewReplacer(".", "_"))
	v.AutomaticEnv()

	_ = v.BindEnv("server.port", "EZ_API_PORT")
	_ = v.BindEnv("server.swagger_host", "EZ_SWAGGER_HOST")
	_ = v.BindEnv("cors.allow_origins", "EZ_CORS_ALLOW_ORIGINS")
	_ = v.BindEnv("postgres.dsn", "EZ_PG_DSN")
	_ = v.BindEnv("redis.addr", "EZ_REDIS_ADDR")
	_ = v.BindEnv("redis.password", "EZ_REDIS_PASSWORD")
	_ = v.BindEnv("redis.db", "EZ_REDIS_DB")
	_ = v.BindEnv("log.batch_size", "EZ_LOG_BATCH_SIZE")
	_ = v.BindEnv("log.flush_ms", "EZ_LOG_FLUSH_MS")
	_ = v.BindEnv("log.queue_capacity", "EZ_LOG_QUEUE")
	_ = v.BindEnv("log.retention_days", "EZ_LOG_RETENTION_DAYS")
	_ = v.BindEnv("log.max_records", "EZ_LOG_MAX_RECORDS")
	_ = v.BindEnv("log.dsn", "EZ_LOG_PG_DSN")
	_ = v.BindEnv("log.partitioning", "EZ_LOG_PARTITIONING")
	_ = v.BindEnv("auth.jwt_secret", "EZ_JWT_SECRET")
	_ = v.BindEnv("model_registry.enabled", "EZ_MODEL_REGISTRY_ENABLED")
	_ = v.BindEnv("model_registry.refresh_seconds", "EZ_MODEL_REGISTRY_REFRESH_SECONDS")
	_ = v.BindEnv("model_registry.models_dev_base_url", "EZ_MODEL_REGISTRY_MODELS_DEV_BASE_URL")
	_ = v.BindEnv("model_registry.models_dev_api_base_url", "EZ_MODEL_REGISTRY_MODELS_DEV_API_BASE_URL")
	_ = v.BindEnv("model_registry.models_dev_ref", "EZ_MODEL_REGISTRY_MODELS_DEV_REF")
	_ = v.BindEnv("model_registry.cache_dir", "EZ_MODEL_REGISTRY_CACHE_DIR")
	_ = v.BindEnv("model_registry.timeout_seconds", "EZ_MODEL_REGISTRY_TIMEOUT_SECONDS")
	_ = v.BindEnv("quota.reset_interval_seconds", "EZ_QUOTA_RESET_INTERVAL_SECONDS")
	_ = v.BindEnv("internal.stats_token", "EZ_INTERNAL_STATS_TOKEN")
	_ = v.BindEnv("internal.allow_anonymous", "EZ_INTERNAL_ALLOW_ANON")
	_ = v.BindEnv("sync_outbox.enabled", "EZ_SYNC_OUTBOX_ENABLED")
	_ = v.BindEnv("sync_outbox.interval_seconds", "EZ_SYNC_OUTBOX_INTERVAL_SECONDS")
	_ = v.BindEnv("sync_outbox.batch_size", "EZ_SYNC_OUTBOX_BATCH_SIZE")
	_ = v.BindEnv("sync_outbox.max_retries", "EZ_SYNC_OUTBOX_MAX_RETRIES")
	_ = v.BindEnv("token_refresh.interval_seconds", "EZ_TOKEN_REFRESH_INTERVAL_SECONDS")
	_ = v.BindEnv("token_refresh.refresh_skew_seconds", "EZ_TOKEN_REFRESH_SKEW_SECONDS")
	_ = v.BindEnv("token_refresh.batch_size", "EZ_TOKEN_REFRESH_BATCH_SIZE")
	_ = v.BindEnv("token_refresh.max_retries", "EZ_TOKEN_REFRESH_MAX_RETRIES")

	if configFile := os.Getenv("EZ_CONFIG_FILE"); configFile != "" {
		v.SetConfigFile(configFile)
	} else {
		v.SetConfigName("config")
		v.SetConfigType("yaml")
		v.AddConfigPath(".")
		v.AddConfigPath("./config")
	}

	if err := v.ReadInConfig(); err != nil {
		if _, ok := err.(viper.ConfigFileNotFoundError); !ok {
			return nil, fmt.Errorf("read config: %w", err)
		}
	}

	cfg := &Config{
		Server: ServerConfig{
			Port:        v.GetString("server.port"),
			SwaggerHost: strings.TrimSpace(v.GetString("server.swagger_host")),
		},
		CORS: CORSConfig{
			AllowOrigins: splitCommaList(v.GetString("cors.allow_origins")),
		},
		Postgres: PostgresConfig{
			DSN: v.GetString("postgres.dsn"),
		},
		Redis: RedisConfig{
			Addr:     v.GetString("redis.addr"),
			Password: v.GetString("redis.password"),
			DB:       v.GetInt("redis.db"),
		},
		Log: LogConfig{
			BatchSize:     v.GetInt("log.batch_size"),
			FlushInterval: time.Duration(v.GetInt("log.flush_ms")) * time.Millisecond,
			QueueCapacity: v.GetInt("log.queue_capacity"),
			RetentionDays: v.GetInt("log.retention_days"),
			MaxRecords:    v.GetInt("log.max_records"),
			DSN:           strings.TrimSpace(v.GetString("log.dsn")),
			Partitioning:  strings.TrimSpace(v.GetString("log.partitioning")),
		},
		Auth: AuthConfig{
			JWTSecret: v.GetString("auth.jwt_secret"),
		},
		ModelRegistry: ModelRegistryConfig{
			Enabled:             v.GetBool("model_registry.enabled"),
			RefreshSeconds:      v.GetInt("model_registry.refresh_seconds"),
			ModelsDevBaseURL:    v.GetString("model_registry.models_dev_base_url"),
			ModelsDevAPIBaseURL: v.GetString("model_registry.models_dev_api_base_url"),
			ModelsDevRef:        v.GetString("model_registry.models_dev_ref"),
			CacheDir:            v.GetString("model_registry.cache_dir"),
			TimeoutSeconds:      v.GetInt("model_registry.timeout_seconds"),
		},
		Quota: QuotaConfig{
			ResetIntervalSeconds: v.GetInt("quota.reset_interval_seconds"),
		},
		Internal: InternalConfig{
			StatsToken:     v.GetString("internal.stats_token"),
			AllowAnonymous: v.GetBool("internal.allow_anonymous"),
		},
		SyncOutbox: SyncOutboxConfig{
			Enabled:         v.GetBool("sync_outbox.enabled"),
			IntervalSeconds: v.GetInt("sync_outbox.interval_seconds"),
			BatchSize:       v.GetInt("sync_outbox.batch_size"),
			MaxRetries:      v.GetInt("sync_outbox.max_retries"),
		},
		TokenRefresh: TokenRefreshConfig{
			IntervalSeconds:    v.GetInt("token_refresh.interval_seconds"),
			RefreshSkewSeconds: v.GetInt("token_refresh.refresh_skew_seconds"),
			BatchSize:          v.GetInt("token_refresh.batch_size"),
			MaxRetries:         v.GetInt("token_refresh.max_retries"),
		},
	}

	return cfg, nil
}

func splitCommaList(raw string) []string {
	parts := strings.Split(raw, ",")
	out := make([]string, 0, len(parts))
	for _, part := range parts {
		part = strings.TrimSpace(part)
		if part == "" {
			continue
		}
		out = append(out, part)
	}
	return out
}