package database

import (
	"os"
	"time"

	"github.com/prometheus/client_golang/prometheus"
)

// Config represents the database configuration structure
type Config struct {
	MySQL DBConfig `yaml:"mysql"`
}

// DBConfig represents the MySQL database configuration
type DBConfig struct {
	DSN    string `default:"" flag:"dsn" usage:"Database DSN"`
	User   string `default:"" flag:"user"`
	Pass   string `default:"" flag:"pass"`
	DBName string // Optional database name override
}

// ConfigOptions allows customization of database opening behavior
type ConfigOptions struct {
	// ConfigFiles is a list of config file paths to search for database configuration
	ConfigFiles []string

	// EnablePoolMonitoring enables connection pool metrics collection
	EnablePoolMonitoring bool

	// PrometheusRegisterer for metrics collection. If nil, no metrics are collected.
	PrometheusRegisterer prometheus.Registerer

	// Connection pool settings
	MaxOpenConns    int
	MaxIdleConns    int
	ConnMaxLifetime time.Duration
}

// getConfigFiles returns the list of config files to search for database configuration.
// If DATABASE_CONFIG_FILE environment variable is set, it returns that single file.
// Otherwise, it returns the default paths.
func getConfigFiles() []string {
	if configFile := os.Getenv("DATABASE_CONFIG_FILE"); configFile != "" {
		return []string{configFile}
	}
	return []string{"database.yaml", "/vault/secrets/database.yaml"}
}

// DefaultConfigOptions returns the standard configuration options used by API package
func DefaultConfigOptions() ConfigOptions {
	return ConfigOptions{
		ConfigFiles:          getConfigFiles(),
		EnablePoolMonitoring: true,
		PrometheusRegisterer: prometheus.DefaultRegisterer,
		MaxOpenConns:         25,
		MaxIdleConns:         10,
		ConnMaxLifetime:      3 * time.Minute,
	}
}

// MonitorConfigOptions returns configuration options optimized for Monitor package
func MonitorConfigOptions() ConfigOptions {
	return ConfigOptions{
		ConfigFiles:          getConfigFiles(),
		EnablePoolMonitoring: false, // Monitor doesn't need metrics
		PrometheusRegisterer: nil,   // No Prometheus dependency
		MaxOpenConns:         10,
		MaxIdleConns:         5,
		ConnMaxLifetime:      3 * time.Minute,
	}
}