package config

import (
	"dario.cat/mergo"
	log "github.com/sirupsen/logrus"
	"gopkg.in/yaml.v3"
	"io/ioutil"
	"os"
	"path/filepath"
	"sync"
)

var (
	instance *Config
	once     sync.Once
)

var DefaultConfigPath = "/usr/share/bbb-graphql-middleware/config.yml"
var OverrideConfigPath = "/etc/bigbluebutton/bbb-graphql-middleware.yml"

type Config struct {
	Server struct {
		Host                          string `yaml:"listen_host"`
		Port                          int    `yaml:"listen_port"`
		MaxConnections                int    `yaml:"max_connections"`
		MaxConnectionsPerSecond       int    `yaml:"max_connections_per_session_token"`
		MaxConnectionsPerSessionToken int    `yaml:"max_connections_per_second"`
		AuthorizedCrossOrigin         string `yaml:"authorized_cross_origin"`
		JsonPatchDisabled             bool   `yaml:"json_patch_disabled"`
		SubscriptionAllowedList       string `yaml:"subscriptions_allowed_list"`
		SubscriptionsDeniedList       string `yaml:"subscriptions_denied_list"`
	} `yaml:"server"`
	Redis struct {
		Host     string `yaml:"host"`
		Port     int32  `yaml:"port"`
		Password string `yaml:"password"`
	} `yaml:"redis"`
	Hasura struct {
		Url string `yaml:"url"`
	} `yaml:"hasura"`
	GraphqlActions struct {
		Url string `yaml:"url"`
	} `yaml:"graphql-actions"`
	AuthHook struct {
		Url string `yaml:"url"`
	} `yaml:"auth_hook"`
	SessionVarsHook struct {
		Url string `yaml:"url"`
	} `yaml:"session_vars_hook"`
	LogLevel                         string `yaml:"log_level"`
	PrometheusAdvancedMetricsEnabled bool   `yaml:"prometheus_advanced_metrics_enabled"`
}

func GetConfig() *Config {
	once.Do(func() {
		instance = &Config{}
		instance.loadConfigs()
	})
	return instance
}

func (c *Config) loadConfigs() {
	// Load default config file
	configDefault, err := loadConfigFile(DefaultConfigPath)
	if err != nil {
		log.Fatalf("Error while loading config file (%s): %v", DefaultConfigPath, err)
	}

	// Load override config file if exists
	if _, err := os.Stat(OverrideConfigPath); err == nil {
		configOverride, err := loadConfigFile(OverrideConfigPath)
		if err != nil {
			log.Fatalf("Error while loading override config file (%s): %v", OverrideConfigPath, err)
		}

		log.Info("Override config found at " + OverrideConfigPath)

		// Use mergo to merge configs
		err = mergo.Merge(&configDefault, configOverride, mergo.WithOverride)
		if err != nil {
			log.Fatalf("Erro ao mesclar as configurações: %v", err)
		}
	}

	// Update the singleton instance with the merged config
	*instance = configDefault
}

func loadConfigFile(path string) (Config, error) {
	var config Config
	data, err := ioutil.ReadFile(filepath.Clean(path))
	if err != nil {
		return config, err
	}

	err = yaml.Unmarshal(data, &config)
	if err != nil {
		return config, err
	}

	return config, nil
}