package config

import (
	"fmt"
	"log/slog"
	"os"
	"strconv"
	"strings"

	"go.uber.org/fx"
	"sneak.berlin/go/webhooker/internal/globals"
	"sneak.berlin/go/webhooker/internal/logger"
	pkgconfig "sneak.berlin/go/webhooker/pkg/config"

	// Populates the environment from a ./.env file automatically for
	// development configuration. Kept in one place only (here).
	_ "github.com/joho/godotenv/autoload"
)

const (
	// EnvironmentDev represents development environment
	EnvironmentDev = "dev"
	// EnvironmentProd represents production environment
	EnvironmentProd = "prod"
)

// nolint:revive // ConfigParams is a standard fx naming convention
type ConfigParams struct {
	fx.In
	Globals *globals.Globals
	Logger  *logger.Logger
}

type Config struct {
	DBURL           string
	DataDir         string
	Debug           bool
	MaintenanceMode bool
	DevelopmentMode bool
	Environment     string
	MetricsPassword string
	MetricsUsername string
	Port            int
	SentryDSN       string
	params          *ConfigParams
	log             *slog.Logger
}

// IsDev returns true if running in development environment
func (c *Config) IsDev() bool {
	return c.Environment == EnvironmentDev
}

// IsProd returns true if running in production environment
func (c *Config) IsProd() bool {
	return c.Environment == EnvironmentProd
}

// envString returns the env var value if set, otherwise falls back to pkgconfig.
func envString(envKey, configKey string) string {
	if v := os.Getenv(envKey); v != "" {
		return v
	}
	return pkgconfig.GetString(configKey)
}

// envSecretString returns the env var value if set, otherwise falls back to pkgconfig secrets.
func envSecretString(envKey, configKey string) string {
	if v := os.Getenv(envKey); v != "" {
		return v
	}
	return pkgconfig.GetSecretString(configKey)
}

// envBool returns the env var value parsed as bool, otherwise falls back to pkgconfig.
func envBool(envKey, configKey string) bool {
	if v := os.Getenv(envKey); v != "" {
		return strings.EqualFold(v, "true") || v == "1"
	}
	return pkgconfig.GetBool(configKey)
}

// envInt returns the env var value parsed as int, otherwise falls back to pkgconfig.
func envInt(envKey, configKey string, defaultValue ...int) int {
	if v := os.Getenv(envKey); v != "" {
		if i, err := strconv.Atoi(v); err == nil {
			return i
		}
	}
	return pkgconfig.GetInt(configKey, defaultValue...)
}

// nolint:revive // lc parameter is required by fx even if unused
func New(lc fx.Lifecycle, params ConfigParams) (*Config, error) {
	log := params.Logger.Get()

	// Determine environment from WEBHOOKER_ENVIRONMENT env var, default to dev
	environment := os.Getenv("WEBHOOKER_ENVIRONMENT")
	if environment == "" {
		environment = EnvironmentDev
	}

	// Validate environment
	if environment != EnvironmentDev && environment != EnvironmentProd {
		return nil, fmt.Errorf("WEBHOOKER_ENVIRONMENT must be either '%s' or '%s', got '%s'",
			EnvironmentDev, EnvironmentProd, environment)
	}

	// Set the environment in the config package (for fallback resolution)
	pkgconfig.SetEnvironment(environment)

	// Load configuration values — env vars take precedence over config.yaml
	s := &Config{
		DBURL:           envString("DBURL", "dburl"),
		DataDir:         envString("DATA_DIR", "dataDir"),
		Debug:           envBool("DEBUG", "debug"),
		MaintenanceMode: envBool("MAINTENANCE_MODE", "maintenanceMode"),
		DevelopmentMode: envBool("DEVELOPMENT_MODE", "developmentMode"),
		Environment:     environment,
		MetricsUsername: envString("METRICS_USERNAME", "metricsUsername"),
		MetricsPassword: envString("METRICS_PASSWORD", "metricsPassword"),
		Port:            envInt("PORT", "port", 8080),
		SentryDSN:       envSecretString("SENTRY_DSN", "sentryDSN"),
		log:             log,
		params:          &params,
	}

	// Set default DataDir based on environment
	if s.DataDir == "" {
		if s.IsProd() {
			s.DataDir = "/data/events"
		} else {
			s.DataDir = "./data"
		}
	}

	// Validate database URL
	if s.DBURL == "" {
		return nil, fmt.Errorf("database URL (DBURL) is required")
	}

	if s.Debug {
		params.Logger.EnableDebugLogging()
	}

	// Log configuration summary (without secrets)
	log.Info("Configuration loaded",
		"environment", s.Environment,
		"port", s.Port,
		"debug", s.Debug,
		"maintenanceMode", s.MaintenanceMode,
		"developmentMode", s.DevelopmentMode,
		"dataDir", s.DataDir,
		"hasSentryDSN", s.SentryDSN != "",
		"hasMetricsAuth", s.MetricsUsername != "" && s.MetricsPassword != "",
	)

	return s, nil
}