package config

import (
	"fmt"
	"time"

	"github.com/spf13/viper"
	"git.warky.dev/wdevs/pgsql-broker/pkg/broker/adapter"
)

// Config holds all broker configuration
type Config struct {
	Databases []DatabaseConfig `mapstructure:"databases"`
	Broker    BrokerConfig     `mapstructure:"broker"`
	Logging   LoggingConfig    `mapstructure:"logging"`
}

// DatabaseConfig holds database connection settings
type DatabaseConfig struct {
	Name            string        `mapstructure:"name"`
	Host            string        `mapstructure:"host"`
	Port            int           `mapstructure:"port"`
	Database        string        `mapstructure:"database"`
	User            string        `mapstructure:"user"`
	Password        string        `mapstructure:"password"`
	SSLMode         string        `mapstructure:"sslmode"`
	MaxOpenConns    int           `mapstructure:"max_open_conns"`
	MaxIdleConns    int           `mapstructure:"max_idle_conns"`
	ConnMaxLifetime time.Duration `mapstructure:"conn_max_lifetime"`
	ConnMaxIdleTime time.Duration `mapstructure:"conn_max_idle_time"`
	QueueCount      int           `mapstructure:"queue_count"`
}

// BrokerConfig holds broker-specific settings
type BrokerConfig struct {
	Name                 string        `mapstructure:"name"`
	FetchQueryQueSize    int           `mapstructure:"fetch_query_que_size"`
	QueueTimerSec        int           `mapstructure:"queue_timer_sec"`
	QueueBufferSize      int           `mapstructure:"queue_buffer_size"`
	WorkerIdleTimeoutSec int           `mapstructure:"worker_idle_timeout_sec"`
	NotifyRetrySeconds   time.Duration `mapstructure:"notify_retry_seconds"`
	EnableDebug          bool          `mapstructure:"enable_debug"`
}

// LoggingConfig holds logging settings
type LoggingConfig struct {
	Level  string `mapstructure:"level"`
	Format string `mapstructure:"format"` // json or text
}

// LoadConfig loads configuration from file and environment variables
func LoadConfig(configPath string) (*Config, error) {
	v := viper.New()

	// Set defaults
	setDefaults(v)

	// Config file settings
	if configPath != "" {
		v.SetConfigFile(configPath)
	} else {
		v.SetConfigName("broker")
		v.SetConfigType("yaml")
		v.AddConfigPath(".")
		v.AddConfigPath("/etc/pgsql-broker/")
		v.AddConfigPath("$HOME/.pgsql-broker/")
	}

	// Read from environment variables
	v.SetEnvPrefix("BROKER")
	v.AutomaticEnv()

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

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

	// Validate configuration
	if err := validateConfig(&config); err != nil {
		return nil, err
	}

	// Apply defaults to databases
	applyDatabaseDefaults(&config)

	return &config, nil
}

// setDefaults sets default configuration values
func setDefaults(v *viper.Viper) {
	// Broker defaults
	v.SetDefault("broker.name", "pgsql-broker")
	v.SetDefault("broker.fetch_query_que_size", 100)
	v.SetDefault("broker.queue_timer_sec", 10)
	v.SetDefault("broker.queue_buffer_size", 50)
	v.SetDefault("broker.worker_idle_timeout_sec", 10)
	v.SetDefault("broker.notify_retry_seconds", 30*time.Second)
	v.SetDefault("broker.enable_debug", false)

	// Logging defaults
	v.SetDefault("logging.level", "info")
	v.SetDefault("logging.format", "json")
}

// validateConfig validates the configuration
func validateConfig(config *Config) error {
	if len(config.Databases) == 0 {
		return fmt.Errorf("at least one database must be configured")
	}

	// Validate each database configuration
	for i, db := range config.Databases {
		if db.Name == "" {
			return fmt.Errorf("database[%d]: name is required", i)
		}
		if db.Host == "" {
			return fmt.Errorf("database[%d] (%s): host is required", i, db.Name)
		}
		if db.Database == "" {
			return fmt.Errorf("database[%d] (%s): database name is required", i, db.Name)
		}
		if db.User == "" {
			return fmt.Errorf("database[%d] (%s): user is required", i, db.Name)
		}
	}

	return nil
}

// applyDatabaseDefaults applies default values to database configurations
func applyDatabaseDefaults(config *Config) {
	for i := range config.Databases {
		db := &config.Databases[i]

		if db.Port == 0 {
			db.Port = 5432
		}
		if db.SSLMode == "" {
			db.SSLMode = "disable"
		}
		if db.MaxOpenConns == 0 {
			db.MaxOpenConns = 25
		}
		if db.MaxIdleConns == 0 {
			db.MaxIdleConns = 5
		}
		if db.ConnMaxLifetime == 0 {
			db.ConnMaxLifetime = 5 * time.Minute
		}
		if db.ConnMaxIdleTime == 0 {
			db.ConnMaxIdleTime = 10 * time.Minute
		}
		if db.QueueCount == 0 {
			db.QueueCount = 4
		}
	}
}

// ToPostgresConfig converts DatabaseConfig to adapter.PostgresConfig
func (d *DatabaseConfig) ToPostgresConfig() adapter.PostgresConfig {
	return adapter.PostgresConfig{
		Host:            d.Host,
		Port:            d.Port,
		Database:        d.Database,
		User:            d.User,
		Password:        d.Password,
		SSLMode:         d.SSLMode,
		MaxOpenConns:    d.MaxOpenConns,
		MaxIdleConns:    d.MaxIdleConns,
		ConnMaxLifetime: d.ConnMaxLifetime,
		ConnMaxIdleTime: d.ConnMaxIdleTime,
	}
}