package server

import (
	"crypto/rsa"
	"encoding/json"
	"git.openprivacy.ca/openprivacy/libricochet-go/utils"
	"io/ioutil"
	"log"
	"sync"
)

// Reporting is a struct for storing a the config a server needs to be a peer, and connect to a group to report
type Reporting struct {
	LogMetricsToFile    bool   `json:"logMetricsToFile"`
	PeerPrivateKey      string `json:"privateKey"`
	ReportingGroupID    string `json:"reportingGroupId"`
	ReportingServerAddr string `json:"reportingServerAddr"`
}

// Config is a struct for storing basic server configuration
type Config struct {
	MaxBufferLines  int       `json:"maxBufferLines"`
	PrivateKeyBytes string    `json:"privateKey"`
	ServerReporting Reporting `json:"serverReporting"`
	lock            sync.Mutex
}

// PrivateKey returns an rsa.PrivateKey generated from the config's PrivateKeyBytes
func (config *Config) PrivateKey() *rsa.PrivateKey {
	pk, err := utils.ParsePrivateKey([]byte(config.PrivateKeyBytes))
	if err != nil {
		log.Println("Error parsing private key: ", err)
	}
	return pk
}

// Save dumps the latest version of the config to a json file given by filename
func (config *Config) Save(filename string) {
	config.lock.Lock()
	defer config.lock.Unlock()
	bytes, _ := json.MarshalIndent(config, "", "\t")
	ioutil.WriteFile(filename, bytes, 0600)
}

// newConfig generates a simple config with defaults. Unmarshal will return them if they aren't specified
func newConfig() *Config {
	config := Config{}
	config.MaxBufferLines = 100000
	config.ServerReporting.LogMetricsToFile = false

	return &config
}

// LoadConfig loads a Config from a json file specified by filename
func LoadConfig(filename string) *Config {
	config := newConfig()

	raw, err := ioutil.ReadFile(filename)
	if err == nil {
		err = json.Unmarshal(raw, &config)

		if err != nil {
			log.Println("Error reading config: ", err)
		}
	}

	configAutoPopulate(config)
	// Always save (first time generation, new version with new variables populated)
	config.Save(filename)
	return config
}

// Auto populate required values if missing and save
func configAutoPopulate(config *Config) {
	if config.PrivateKeyBytes == "" {
		config.generatePrivateKey()
	}

	if config.ServerReporting.PeerPrivateKey == "" {
		config.generatePeerPrivateKey()
	}
}

func (config *Config) generatePrivateKey() {
	pk, err := utils.GeneratePrivateKey()
	if err != nil {
		log.Fatalf("error generating new private key: %v\n", err)
	}
	config.lock.Lock()
	config.PrivateKeyBytes = utils.PrivateKeyToString(pk)
	config.lock.Unlock()
}

func (config *Config) generatePeerPrivateKey() {
	pk, err := utils.GeneratePrivateKey()
	if err != nil {
		log.Fatalf("error generating new peer private key: %v\n", err)
	}
	config.lock.Lock()
	config.ServerReporting.PeerPrivateKey = utils.PrivateKeyToString(pk)
	config.lock.Unlock()
}