package config

import (
	"encoding"
	"encoding/base64"
	"github.com/mitchellh/mapstructure"
	"github.com/spf13/viper"
	"go.uber.org/fx"
	"go.uber.org/zap"
)

import (
	"crypto/ed25519"
)

type PrivateKey ed25519.PrivateKey

var (
	_ encoding.TextUnmarshaler = (*PrivateKey)(nil)
)

func (p *PrivateKey) UnmarshalText(text []byte) error {
	dec, err := base64.StdEncoding.DecodeString(string(text))
	if err != nil {
		return err
	}

	*p = dec

	return nil
}

type Config struct {
	Host               string `mapstructure:"host"`
	Port               int    `mapstructure:"port"`
	GiteaUrl           string `mapstructure:"gitea_url"`
	DbPath             string `mapstructure:"db_path"`
	Oauth              OauthConfig
	JwtPrivateKey      PrivateKey
	Domain             string `mapstructure:"domain"`
	GiteaWebHookSecret string `mapstructure:"gitea_webhook_secret"`
}

type OauthConfig struct {
	Authorization string `mapstructure:"authorization"`
	Token         string `mapstructure:"token"`
	ClientId      string `mapstructure:"client_id"`
	ClientSecret  string `mapstructure:"client_secret"`
	RefreshToken  string `mapstructure:"refresh_token"`
}

var Module = fx.Module("config",
	fx.Options(
		fx.Provide(NewConfig),
	),
)

func NewConfig(logger *zap.Logger) *Config {
	c := &Config{}

	cfg := viper.New()

	_, sk, err := ed25519.GenerateKey(nil)

	if err != nil {
		logger.Fatal("Error generating private key", zap.Error(err))
	}

	// Set the default values
	cfg.SetDefault("host", "localhost")
	cfg.SetDefault("port", 8080)
	cfg.SetDefault("gitea_url", "")
	cfg.SetDefault("db_path", "data.db")
	cfg.SetDefault("jwt_private_key", base64.StdEncoding.EncodeToString(sk))
	cfg.SetDefault("oauth.client_id", "")
	cfg.SetDefault("oauth.client_secret", "")

	cfg.AddConfigPath(".")
	cfg.AddConfigPath("/etc/gitea-github-proxy")
	cfg.SetConfigName("config")
	cfg.SetConfigType("yaml")
	err = cfg.ReadInConfig()
	if err != nil {
		err = cfg.SafeWriteConfig()
		if err != nil {
			logger.Fatal("Error writing config file", zap.Error(err))
		}
	}

	err = cfg.Unmarshal(c)
	if err != nil {
		logger.Fatal("Error unmarshalling config", zap.Error(err))
	}

	err = cfg.UnmarshalKey("jwt_private_key", &c.JwtPrivateKey, viper.DecodeHook(mapstructure.TextUnmarshallerHookFunc()))
	if err != nil {
		logger.Fatal("Error unmarshalling jwtPrivateKey", zap.Error(err))
	}

	if len(c.GiteaUrl) == 0 {
		logger.Fatal("Gitea URL is required")
	}

	return c
}

func SaveConfig(cfg *Config) error {
	err := viper.Unmarshal(cfg)
	if err != nil {
		return err
	}

	return viper.WriteConfig()
}