package config

import (
	"math"
	"os"

	"git.burning.moe/celediel/burning.moe/internal/models"
	"github.com/charmbracelet/log"
	"github.com/ilyakaznacheev/cleanenv"
)

// AppConfig contains data to be accessed across the app.
type AppConfig struct {
	ListenPort    uint16
	TemplateCache models.TemplateCache
	UseCache      bool
	Logger        *log.Logger
	LogLevel      log.Level
}

// defaluts contains default settings that are used if no environmental variables are set
var defaults = &AppConfig{
	ListenPort: 9001,
	UseCache:   true,
	LogLevel:   log.InfoLevel,
}

// ConfigDatabase contains data to be loaded from environmental variables
type ConfigDatabase struct {
	Port     uint16 `env:"PORT" env-default:"9001" env-description:"server port"`
	LogLevel string `env:"LOGLEVEL" env-default:"warn" env-description:"Logging level. Default: warn, Possible values: debug info warn error fatal none"`
	UseCache bool   `env:"CACHE" env-default:"true" env-description:"Use template cache"`
}

// Initialises the app wide AppConfig, loads values from environment, and set up the Logger
func Initialise() AppConfig {
	app := *defaults
	app.Logger = log.New(os.Stderr)

	// load values from config
	if cfg, err := loadConfig(); err == nil {
		app.ListenPort = cfg.Port
		app.UseCache = cfg.UseCache
		app.LogLevel = logLevelFromString(cfg.LogLevel)
	} else {
		app.Logger.Print("Failed loading config from environment", "err", err)
	}

	app.Logger.SetLevel(app.LogLevel)
	app.Logger.Debug("Loaded config from environment:", "port", app.ListenPort, "useCache", app.UseCache, "log_level", app.LogLevel)

	return app
}

// loadConfig utilises cleanenv to load config values from the environment
func loadConfig() (ConfigDatabase, error) {
	var cfg ConfigDatabase
	if err := cleanenv.ReadEnv(&cfg); err != nil {
		return ConfigDatabase{}, err
	} else {
		return cfg, nil
	}
}

// logLevelFromString turns a string like "warn" into a log.Level like log.WarnLevel
func logLevelFromString(level string) log.Level {
	switch level {
	case "debug":
		return log.DebugLevel
	case "info":
		return log.InfoLevel
	case "warn":
		return log.WarnLevel
	case "error":
		return log.ErrorLevel
	case "fatal":
		return log.FatalLevel
	case "none":
		return math.MaxInt32
	default:
		return defaults.LogLevel
	}
}