package config

import (
	"fmt"

	"github.com/spf13/viper"
	"go.uber.org/zap"
)

// Config 应用配置
type Config struct {
	Mode      string          `mapstructure:"mode"`
	Port      string          `mapstructure:"port"`
	LogLevel  string          `mapstructure:"log_level"`
	Database  DatabaseConfig  `mapstructure:"database"`
	JWT       JWTConfig       `mapstructure:"jwt"`
	Agent     AgentConfig     `mapstructure:"agent"`
	Retention RetentionConfig `mapstructure:"retention"`
	Billing   BillingConfig   `mapstructure:"billing"`
	Redis     RedisConfig     `mapstructure:"redis"`
	Websocket WebsocketConfig `mapstructure:"websocket"`
}

// BillingConfig 定义云账单报告本位币及各原币种折算到 CNY 的汇率。 // Logan.Li
type BillingConfig struct {
	BaseCurrency  string             `mapstructure:"base_currency"`
	ExchangeRates map[string]float64 `mapstructure:"exchange_rates"`
}

// DatabaseConfig 数据库配置
type DatabaseConfig struct {
	Driver   string `mapstructure:"driver"`
	Host     string `mapstructure:"host"`
	Port     int    `mapstructure:"port"`
	User     string `mapstructure:"user"`
	Password string `mapstructure:"password"`
	DBName   string `mapstructure:"dbname"`
	Charset  string `mapstructure:"charset"`
	MaxConn  int    `mapstructure:"max_conn"`
	MaxIdle  int    `mapstructure:"max_idle"`
}

// JWTConfig JWT配置
type JWTConfig struct {
	Secret     string `mapstructure:"secret"`
	ExpireHour int    `mapstructure:"expire_hour"`
}

// AgentConfig Agent 接入安全配置。 // Logan.Li
type AgentConfig struct {
	EnforceAuth bool `mapstructure:"enforce_auth"`
}

// RetentionConfig 高频数据保留期配置，单位为天。 // Logan.Li
type RetentionConfig struct {
	AgentReportsDays    int `mapstructure:"agent_reports_days"`
	MetricHistoryDays   int `mapstructure:"metric_history_days"`
	MetricAggregateDays int `mapstructure:"metric_aggregate_days"`
	SNMPSamplesDays     int `mapstructure:"snmp_samples_days"`
	SiteResultsDays     int `mapstructure:"site_results_days"`
	LogEntriesDays      int `mapstructure:"log_entries_days"`
	CleanupBatchSize    int `mapstructure:"cleanup_batch_size"`
}

// RedisConfig Redis配置
type RedisConfig struct {
	Driver   string `mapstructure:"driver"` // redka (内嵌) / redis (外部)
	Host     string `mapstructure:"host"`
	Port     int    `mapstructure:"port"`
	Password string `mapstructure:"password"`
	DB       int    `mapstructure:"db"`
}

// WebsocketConfig WebSocket配置
type WebsocketConfig struct {
	ReadBufferSize  int `mapstructure:"read_buffer_size"`
	WriteBufferSize int `mapstructure:"write_buffer_size"`
}

// Load 加载配置
func Load() *Config {
	viper.SetConfigName("config")
	viper.SetConfigType("yaml")
	viper.AddConfigPath("./configs")
	viper.AddConfigPath(".")

	// 设置默认值
	viper.SetDefault("mode", "development")
	viper.SetDefault("port", "8080")
	viper.SetDefault("log_level", "info")
	viper.SetDefault("database.driver", "sqlite")
	viper.SetDefault("database.dbname", "sqlite3.db")
	viper.SetDefault("database.host", "localhost")
	viper.SetDefault("database.port", 3306)
	viper.SetDefault("database.charset", "utf8mb4")
	viper.SetDefault("database.max_conn", 100)
	viper.SetDefault("database.max_idle", 10)
	viper.SetDefault("jwt.expire_hour", 24)
	viper.SetDefault("agent.enforce_auth", false)
	viper.SetDefault("retention.agent_reports_days", 7)
	viper.SetDefault("retention.metric_history_days", 30)
	viper.SetDefault("retention.metric_aggregate_days", 365)
	viper.SetDefault("retention.snmp_samples_days", 30)
	viper.SetDefault("retention.site_results_days", 30)
	viper.SetDefault("retention.log_entries_days", 30)
	viper.SetDefault("retention.cleanup_batch_size", 10000)
	viper.SetDefault("billing.base_currency", "CNY")
	viper.SetDefault("billing.exchange_rates.CNY", 1.0)
	viper.SetDefault("billing.exchange_rates.USD", 7.2)
	viper.SetDefault("redis.host", "localhost")
	viper.SetDefault("redis.port", 6379)
	viper.SetDefault("redis.driver", "redka")
	viper.SetDefault("websocket.read_buffer_size", 1024)
	viper.SetDefault("websocket.write_buffer_size", 1024)

	// 读取环境变量
	viper.AutomaticEnv()

	var cfg Config
	if err := viper.ReadInConfig(); err != nil {
		zap.L().Warn("config file not found, using defaults", zap.Error(err))
	}

	if err := viper.Unmarshal(&cfg); err != nil {
		zap.L().Fatal("failed to unmarshal config", zap.Error(err))
	}

	return &cfg
}

// DSN 返回数据库连接字符串
func (d *DatabaseConfig) DSN() string {
	if d.Driver == "mysql" {
		return fmt.Sprintf("%s:%s@tcp(%s:%d)/%s?charset=%s&parseTime=True&loc=Local",
			d.User, d.Password, d.Host, d.Port, d.DBName, d.Charset)
	}
	if d.Driver == "sqlite" {
		return d.DBName
	}
	return ""
}