package common

import (
	"encoding/json"
	"errors"
	"io/ioutil"
	"log"
	"strconv"
	"strings"
)

// Site holds the basic settings which should be tweaked when setting up a site, we might move them to the settings table at some point
var Site = &site{Name: "Magical Fairy Land", Language: "english"}

// DbConfig holds the database configuration
var DbConfig = &dbConfig{Host: "localhost"}

// Config holds the more technical settings
var Config = new(config)

// Dev holds build flags and other things which should only be modified during developers or to gather additional test data
var Dev = new(devConfig)

type site struct {
	ShortName    string
	Name         string
	Email        string
	URL          string
	Host         string
	Port         string
	EnableSsl    bool
	EnableEmails bool
	HasProxy     bool
	Language     string

	MaxRequestSize int // Alias, do not modify, will be overwritten
}

type dbConfig struct {
	// Production database
	Adapter  string
	Host     string
	Username string
	Password string
	Dbname   string
	Port     string

	// Test database. Split this into a separate variable?
	TestAdapter  string
	TestHost     string
	TestUsername string
	TestPassword string
	TestDbname   string
	TestPort     string
}

type config struct {
	SslPrivkey   string
	SslFullchain string
	HashAlgo     string // Defaults to bcrypt, and in the future, possibly something stronger

	MaxRequestSizeStr  string
	MaxRequestSize     int
	UserCache          string
	UserCacheCapacity  int
	TopicCache         string
	TopicCacheCapacity int

	SMTPServer    string
	SMTPUsername  string
	SMTPPassword  string
	SMTPPort      string
	SMTPEnableTLS bool

	Search string

	DefaultPath     string
	DefaultGroup    int    // Should be a setting in the database
	ActivationGroup int    // Should be a setting in the database
	StaffCSS        string // ? - Move this into the settings table? Might be better to implement this as Group CSS
	DefaultForum    int    // The forum posts go in by default, this used to be covered by the Uncategorised Forum, but we want to replace it with a more robust solution. Make this a setting?
	MinifyTemplates bool
	BuildSlugs      bool // TODO: Make this a setting?
	ServerCount     int

	DisableLiveTopicList bool
	DisableJSAntispam    bool
	//LooseCSP             bool

	Noavatar            string // ? - Move this into the settings table?
	ItemsPerPage        int    // ? - Move this into the settings table?
	MaxTopicTitleLength int
	MaxUsernameLength   int
}

type devConfig struct {
	DebugMode     bool
	SuperDebug    bool
	TemplateDebug bool
	Profiling     bool
	TestDB        bool
	NoFsnotify    bool // Super Experimental!
}

// configHolder is purely for having a big struct to unmarshal data into
type configHolder struct {
	Site     *site
	Config   *config
	Database *dbConfig
	Dev      *devConfig
}

func LoadConfig() error {
	data, err := ioutil.ReadFile("./config/config.json")
	if err != nil {
		return err
	}

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

	Site = config.Site
	Config = config.Config
	DbConfig = config.Database
	Dev = config.Dev

	return nil
}

func ProcessConfig() (err error) {
	Config.Noavatar = strings.Replace(Config.Noavatar, "{site_url}", Site.URL, -1)
	guestAvatar = GuestAvatar{buildNoavatar(0, 200), buildNoavatar(0, 48)}
	Site.Host = Site.URL
	if Site.Port != "80" && Site.Port != "443" {
		Site.URL = strings.TrimSuffix(Site.URL, "/")
		Site.URL = strings.TrimSuffix(Site.URL, "\\")
		Site.URL = strings.TrimSuffix(Site.URL, ":")
		Site.URL = Site.URL + ":" + Site.Port
	}
	if Config.DefaultPath == "" {
		Config.DefaultPath = "/topics/"
	}

	// TODO: Bump the size of max request size up, if it's too low
	Config.MaxRequestSize, err = strconv.Atoi(Config.MaxRequestSizeStr)
	if err != nil {
		reqSizeStr := Config.MaxRequestSizeStr
		if len(reqSizeStr) < 3 {
			return errors.New("Invalid unit for MaxRequestSizeStr")
		}

		quantity, err := strconv.Atoi(reqSizeStr[:len(reqSizeStr)-2])
		if err != nil {
			return errors.New("Unable to convert quantity to integer in MaxRequestSizeStr, found " + reqSizeStr[:len(reqSizeStr)-2])
		}
		unit := reqSizeStr[len(reqSizeStr)-2:]

		// TODO: Make it a named error just in case new errors are added in here in the future
		Config.MaxRequestSize, err = FriendlyUnitToBytes(quantity, unit)
		if err != nil {
			return errors.New("Unable to recognise unit for MaxRequestSizeStr, found " + unit)
		}
	}
	if Dev.DebugMode {
		log.Print("Set MaxRequestSize to ", Config.MaxRequestSize)
	}
	if Config.MaxRequestSize <= 0 {
		log.Fatal("MaxRequestSize should not be zero or below")
	}
	Site.MaxRequestSize = Config.MaxRequestSize

	// ? Find a way of making these unlimited if zero? It might rule out some optimisations, waste memory, and break layouts
	if Config.MaxTopicTitleLength == 0 {
		Config.MaxTopicTitleLength = 100
	}
	if Config.MaxUsernameLength == 0 {
		Config.MaxUsernameLength = 100
	}
	GuestUser.Avatar, GuestUser.MicroAvatar = BuildAvatar(0, "")

	if Config.HashAlgo != "" {
		// TODO: Set the alternate hash algo, e.g. argon2
	}

	// We need this in here rather than verifyConfig as switchToTestDB() currently overwrites the values it verifies
	if DbConfig.TestDbname == DbConfig.Dbname {
		return errors.New("Your test database can't have the same name as your production database")
	}
	if Dev.TestDB {
		SwitchToTestDB()
	}
	return nil
}

func VerifyConfig() error {
	if !Forums.Exists(Config.DefaultForum) {
		return errors.New("Invalid default forum")
	}
	if Config.ServerCount < 1 {
		return errors.New("You can't have less than one server")
	}
	if Config.MaxTopicTitleLength > 100 {
		return errors.New("The max topic title length cannot be over 100 as that's unable to fit in the database row")
	}
	if Config.MaxUsernameLength > 100 {
		return errors.New("The max username length cannot be over 100 as that's unable to fit in the database row")
	}
	return nil
}

func SwitchToTestDB() {
	DbConfig.Host = DbConfig.TestHost
	DbConfig.Username = DbConfig.TestUsername
	DbConfig.Password = DbConfig.TestPassword
	DbConfig.Dbname = DbConfig.TestDbname
	DbConfig.Port = DbConfig.TestPort
}