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)

var PluginConfig = map[string]string{}

type site struct {
	ShortName    string
	Name         string
	Email        string
	URL          string
	Host         string
	LocalHost    bool // Used internally, do not modify as it will be overwritten
	Port         string
	PortInt      int // Alias for efficiency, do not modify, will be overwritten
	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
	ConvoKey     string

	MaxRequestSizeStr  string
	MaxRequestSize     int
	UserCache          string
	UserCacheCapacity  int
	TopicCache         string
	TopicCacheCapacity int
	ReplyCache         string
	ReplyCacheCapacity 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?

	PrimaryServer  bool
	ServerCount    int
	LastIPCutoff   int // Currently just -1, non--1, but will accept the number of months a user's last IP should be retained for in the future before being purged. Please note that the other two cutoffs below operate off the numbers of days instead.
	PostIPCutoff   int
	PollIPCutoff int
	LogPruneCutoff int

	DisableLiveTopicList bool
	DisableJSAntispam    bool
	//LooseCSP             bool
	LooseHost              bool
	LoosePort              bool
	SslSchema              bool // Pretend we're using SSL, might be useful if a reverse-proxy terminates SSL in-front of Gosora
	DisableServerPush      bool
	EnableCDNPush          bool
	DisableNoavatarRange   bool
	DisableDefaultNoavatar bool

	RefNoTrack bool
	RefNoRef   bool
	NoEmbed    bool

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

	ReadTimeout  int
	WriteTimeout int
	IdleTimeout  int
}

type devConfig struct {
	DebugMode     bool
	SuperDebug    bool
	TemplateDebug bool
	Profiling     bool
	TestDB        bool

	NoFsnotify bool // Super Experimental!
	FullReqLog bool
	ExtraTmpls string // Experimental flag for adding compiled templates, we'll likely replace this with a better mechanism
}

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

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
	PluginConfig = config.Plugin

	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)}

	// Strip these unnecessary bits, if we find them.
	Site.URL = strings.TrimPrefix(Site.URL, "http://")
	Site.URL = strings.TrimPrefix(Site.URL, "https://")
	Site.Host = Site.URL
	Site.LocalHost = Site.Host == "localhost" || Site.Host == "127.0.0.1" || Site.Host == "::1"
	Site.PortInt, err = strconv.Atoi(Site.Port)
	if err != nil {
		return errors.New("The port must be a valid integer")
	}
	if Site.PortInt != 80 && Site.PortInt != 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 Site.EnableSsl {
		Config.SslSchema = Site.EnableSsl
	}
	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

	if Config.PostIPCutoff == 0 {
		Config.PostIPCutoff = 120 // Default cutoff
	}
	if Config.LogPruneCutoff == 0 {
		Config.LogPruneCutoff = 180 // Default cutoff
	}
	if Config.LastIPCutoff == 0 {
		Config.LastIPCutoff = 3 // Default cutoff
	}
	if Config.LastIPCutoff > 12 {
		Config.LastIPCutoff = 12
	}
	if Config.PollIPCutoff == 0 {
		Config.PollIPCutoff = 720 // Default cutoff
	}
	if Config.NoEmbed {
		DefaultParseSettings.NoEmbed = true
	}

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

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