// Discordgo - Discord bindings for Go
// Available at https://github.com/bwmarrin/discordgo

// Copyright 2015-2016 Bruce Marriner <bruce@sqls.net>.  All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// This file contains all structures for the discordgo package.  These
// may be moved about later into separate files but I find it easier to have
// them all located together.

package discordgo

import (
	"encoding/json"
	"net/http"
	"strconv"
	"sync"
	"time"

	"github.com/gorilla/websocket"
)

// A Session represents a connection to the Discord API.
type Session struct {
	sync.RWMutex

	// General configurable settings.

	// Authentication token for this session
	Token string
	MFA   bool

	// Debug for printing JSON request/responses
	Debug    bool // Deprecated, will be removed.
	LogLevel int

	// Should the session reconnect the websocket on errors.
	ShouldReconnectOnError bool

	// Should the session request compressed websocket data.
	Compress bool

	// Sharding
	ShardID    int
	ShardCount int

	// Should state tracking be enabled.
	// State tracking is the best way for getting the the users
	// active guilds and the members of the guilds.
	StateEnabled bool

	// Whether or not to call event handlers synchronously.
	// e.g false = launch event handlers in their own goroutines.
	SyncEvents bool

	// Exposed but should not be modified by User.

	// Whether the Data Websocket is ready
	DataReady bool // NOTE: Maye be deprecated soon

	// Max number of REST API retries
	MaxRestRetries int

	// Status stores the currect status of the websocket connection
	// this is being tested, may stay, may go away.
	status int32

	// Whether the Voice Websocket is ready
	VoiceReady bool // NOTE: Deprecated.

	// Whether the UDP Connection is ready
	UDPReady bool // NOTE: Deprecated

	// Stores a mapping of guild id's to VoiceConnections
	VoiceConnections map[string]*VoiceConnection

	// Managed state object, updated internally with events when
	// StateEnabled is true.
	State *State

	// The http client used for REST requests
	Client *http.Client

	// Stores the last HeartbeatAck that was recieved (in UTC)
	LastHeartbeatAck time.Time

	// Event handlers
	handlersMu   sync.RWMutex
	handlers     map[string][]*eventHandlerInstance
	onceHandlers map[string][]*eventHandlerInstance

	// The websocket connection.
	wsConn *websocket.Conn

	// When nil, the session is not listening.
	listening chan interface{}

	// used to deal with rate limits
	ratelimiter *RateLimiter

	// sequence tracks the current gateway api websocket sequence number
	sequence *int64

	// stores sessions current Discord Gateway
	gateway string

	// stores session ID of current Gateway connection
	sessionID string

	// used to make sure gateway websocket writes do not happen concurrently
	wsMutex sync.Mutex
}

// A VoiceRegion stores data for a specific voice region server.
type VoiceRegion struct {
	ID       string `json:"id"`
	Name     string `json:"name"`
	Hostname string `json:"sample_hostname"`
	Port     int    `json:"sample_port"`
}

// A VoiceICE stores data for voice ICE servers.
type VoiceICE struct {
	TTL     string       `json:"ttl"`
	Servers []*ICEServer `json:"servers"`
}

// A ICEServer stores data for a specific voice ICE server.
type ICEServer struct {
	URL        string `json:"url"`
	Username   string `json:"username"`
	Credential string `json:"credential"`
}

// A Invite stores all data related to a specific Discord Guild or Channel invite.
type Invite struct {
	Guild     *Guild    `json:"guild"`
	Channel   *Channel  `json:"channel"`
	Inviter   *User     `json:"inviter"`
	Code      string    `json:"code"`
	CreatedAt Timestamp `json:"created_at"`
	MaxAge    int       `json:"max_age"`
	Uses      int       `json:"uses"`
	MaxUses   int       `json:"max_uses"`
	XkcdPass  string    `json:"xkcdpass"`
	Revoked   bool      `json:"revoked"`
	Temporary bool      `json:"temporary"`
}

// ChannelType is the type of a Channel
type ChannelType int

// Block contains known ChannelType values
const (
	ChannelTypeGuildText ChannelType = iota
	ChannelTypeDM
	ChannelTypeGuildVoice
	ChannelTypeGroupDM
	ChannelTypeGuildCategory
)

// A Channel holds all data related to an individual Discord channel.
type Channel struct {
	ID                   string                 `json:"id"`
	GuildID              string                 `json:"guild_id"`
	Name                 string                 `json:"name"`
	Topic                string                 `json:"topic"`
	Type                 ChannelType            `json:"type"`
	LastMessageID        string                 `json:"last_message_id"`
	NSFW                 bool                   `json:"nsfw"`
	Position             int                    `json:"position"`
	Bitrate              int                    `json:"bitrate"`
	Recipients           []*User                `json:"recipient"`
	Messages             []*Message             `json:"-"`
	PermissionOverwrites []*PermissionOverwrite `json:"permission_overwrites"`
}

// A PermissionOverwrite holds permission overwrite data for a Channel
type PermissionOverwrite struct {
	ID    string `json:"id"`
	Type  string `json:"type"`
	Deny  int    `json:"deny"`
	Allow int    `json:"allow"`
}

// Emoji struct holds data related to Emoji's
type Emoji struct {
	ID            string   `json:"id"`
	Name          string   `json:"name"`
	Roles         []string `json:"roles"`
	Managed       bool     `json:"managed"`
	RequireColons bool     `json:"require_colons"`
}

// APIName returns an correctly formatted API name for use in the MessageReactions endpoints.
func (e *Emoji) APIName() string {
	if e.ID != "" && e.Name != "" {
		return e.Name + ":" + e.ID
	}
	if e.Name != "" {
		return e.Name
	}
	return e.ID
}

// VerificationLevel type defination
type VerificationLevel int

// Constants for VerificationLevel levels from 0 to 3 inclusive
const (
	VerificationLevelNone VerificationLevel = iota
	VerificationLevelLow
	VerificationLevelMedium
	VerificationLevelHigh
)

// A Guild holds all data related to a specific Discord Guild.  Guilds are also
// sometimes referred to as Servers in the Discord client.
type Guild struct {
	ID                          string            `json:"id"`
	Name                        string            `json:"name"`
	Icon                        string            `json:"icon"`
	Region                      string            `json:"region"`
	AfkChannelID                string            `json:"afk_channel_id"`
	EmbedChannelID              string            `json:"embed_channel_id"`
	OwnerID                     string            `json:"owner_id"`
	JoinedAt                    Timestamp         `json:"joined_at"`
	Splash                      string            `json:"splash"`
	AfkTimeout                  int               `json:"afk_timeout"`
	MemberCount                 int               `json:"member_count"`
	VerificationLevel           VerificationLevel `json:"verification_level"`
	EmbedEnabled                bool              `json:"embed_enabled"`
	Large                       bool              `json:"large"` // ??
	DefaultMessageNotifications int               `json:"default_message_notifications"`
	Roles                       []*Role           `json:"roles"`
	Emojis                      []*Emoji          `json:"emojis"`
	Members                     []*Member         `json:"members"`
	Presences                   []*Presence       `json:"presences"`
	Channels                    []*Channel        `json:"channels"`
	VoiceStates                 []*VoiceState     `json:"voice_states"`
	Unavailable                 bool              `json:"unavailable"`
}

// A UserGuild holds a brief version of a Guild
type UserGuild struct {
	ID          string `json:"id"`
	Name        string `json:"name"`
	Icon        string `json:"icon"`
	Owner       bool   `json:"owner"`
	Permissions int    `json:"permissions"`
}

// A GuildParams stores all the data needed to update discord guild settings
type GuildParams struct {
	Name                        string             `json:"name,omitempty"`
	Region                      string             `json:"region,omitempty"`
	VerificationLevel           *VerificationLevel `json:"verification_level,omitempty"`
	DefaultMessageNotifications int                `json:"default_message_notifications,omitempty"` // TODO: Separate type?
	AfkChannelID                string             `json:"afk_channel_id,omitempty"`
	AfkTimeout                  int                `json:"afk_timeout,omitempty"`
	Icon                        string             `json:"icon,omitempty"`
	OwnerID                     string             `json:"owner_id,omitempty"`
	Splash                      string             `json:"splash,omitempty"`
}

// A Role stores information about Discord guild member roles.
type Role struct {
	ID          string `json:"id"`
	Name        string `json:"name"`
	Managed     bool   `json:"managed"`
	Mentionable bool   `json:"mentionable"`
	Hoist       bool   `json:"hoist"`
	Color       int    `json:"color"`
	Position    int    `json:"position"`
	Permissions int    `json:"permissions"`
}

// Roles are a collection of Role
type Roles []*Role

func (r Roles) Len() int {
	return len(r)
}

func (r Roles) Less(i, j int) bool {
	return r[i].Position > r[j].Position
}

func (r Roles) Swap(i, j int) {
	r[i], r[j] = r[j], r[i]
}

// A VoiceState stores the voice states of Guilds
type VoiceState struct {
	UserID    string `json:"user_id"`
	SessionID string `json:"session_id"`
	ChannelID string `json:"channel_id"`
	GuildID   string `json:"guild_id"`
	Suppress  bool   `json:"suppress"`
	SelfMute  bool   `json:"self_mute"`
	SelfDeaf  bool   `json:"self_deaf"`
	Mute      bool   `json:"mute"`
	Deaf      bool   `json:"deaf"`
}

// A Presence stores the online, offline, or idle and game status of Guild members.
type Presence struct {
	User   *User    `json:"user"`
	Status Status   `json:"status"`
	Game   *Game    `json:"game"`
	Nick   string   `json:"nick"`
	Roles  []string `json:"roles"`
	Since  *int     `json:"since"`
}

// A Game struct holds the name of the "playing .." game for a user
type Game struct {
	Name string `json:"name"`
	Type int    `json:"type"`
	URL  string `json:"url,omitempty"`
}

// UnmarshalJSON unmarshals json to Game struct
func (g *Game) UnmarshalJSON(bytes []byte) error {
	temp := &struct {
		Name json.Number     `json:"name"`
		Type json.RawMessage `json:"type"`
		URL  string          `json:"url"`
	}{}
	err := json.Unmarshal(bytes, temp)
	if err != nil {
		return err
	}
	g.URL = temp.URL
	g.Name = temp.Name.String()

	if temp.Type != nil {
		err = json.Unmarshal(temp.Type, &g.Type)
		if err == nil {
			return nil
		}

		s := ""
		err = json.Unmarshal(temp.Type, &s)
		if err == nil {
			g.Type, err = strconv.Atoi(s)
		}

		return err
	}

	return nil
}

// A Member stores user information for Guild members.
type Member struct {
	GuildID  string   `json:"guild_id"`
	JoinedAt string   `json:"joined_at"`
	Nick     string   `json:"nick"`
	Deaf     bool     `json:"deaf"`
	Mute     bool     `json:"mute"`
	User     *User    `json:"user"`
	Roles    []string `json:"roles"`
}

// A Settings stores data for a specific users Discord client settings.
type Settings struct {
	RenderEmbeds           bool               `json:"render_embeds"`
	InlineEmbedMedia       bool               `json:"inline_embed_media"`
	InlineAttachmentMedia  bool               `json:"inline_attachment_media"`
	EnableTtsCommand       bool               `json:"enable_tts_command"`
	MessageDisplayCompact  bool               `json:"message_display_compact"`
	ShowCurrentGame        bool               `json:"show_current_game"`
	ConvertEmoticons       bool               `json:"convert_emoticons"`
	Locale                 string             `json:"locale"`
	Theme                  string             `json:"theme"`
	GuildPositions         []string           `json:"guild_positions"`
	RestrictedGuilds       []string           `json:"restricted_guilds"`
	FriendSourceFlags      *FriendSourceFlags `json:"friend_source_flags"`
	Status                 Status             `json:"status"`
	DetectPlatformAccounts bool               `json:"detect_platform_accounts"`
	DeveloperMode          bool               `json:"developer_mode"`
}

// Status type defination
type Status string

// Constants for Status with the different current available status
const (
	StatusOnline       Status = "online"
	StatusIdle         Status = "idle"
	StatusDoNotDisturb Status = "dnd"
	StatusInvisible    Status = "invisible"
	StatusOffline      Status = "offline"
)

// FriendSourceFlags stores ... TODO :)
type FriendSourceFlags struct {
	All           bool `json:"all"`
	MutualGuilds  bool `json:"mutual_guilds"`
	MutualFriends bool `json:"mutual_friends"`
}

// A Relationship between the logged in user and Relationship.User
type Relationship struct {
	User *User  `json:"user"`
	Type int    `json:"type"` // 1 = friend, 2 = blocked, 3 = incoming friend req, 4 = sent friend req
	ID   string `json:"id"`
}

// A TooManyRequests struct holds information received from Discord
// when receiving a HTTP 429 response.
type TooManyRequests struct {
	Bucket     string        `json:"bucket"`
	Message    string        `json:"message"`
	RetryAfter time.Duration `json:"retry_after"`
}

// A ReadState stores data on the read state of channels.
type ReadState struct {
	MentionCount  int    `json:"mention_count"`
	LastMessageID string `json:"last_message_id"`
	ID            string `json:"id"`
}

// An Ack is used to ack messages
type Ack struct {
	Token string `json:"token"`
}

// A GuildRole stores data for guild roles.
type GuildRole struct {
	Role    *Role  `json:"role"`
	GuildID string `json:"guild_id"`
}

// A GuildBan stores data for a guild ban.
type GuildBan struct {
	Reason string `json:"reason"`
	User   *User  `json:"user"`
}

// A GuildIntegration stores data for a guild integration.
type GuildIntegration struct {
	ID                string                   `json:"id"`
	Name              string                   `json:"name"`
	Type              string                   `json:"type"`
	Enabled           bool                     `json:"enabled"`
	Syncing           bool                     `json:"syncing"`
	RoleID            string                   `json:"role_id"`
	ExpireBehavior    int                      `json:"expire_behavior"`
	ExpireGracePeriod int                      `json:"expire_grace_period"`
	User              *User                    `json:"user"`
	Account           *GuildIntegrationAccount `json:"account"`
	SyncedAt          int                      `json:"synced_at"`
}

// A GuildIntegrationAccount stores data for a guild integration account.
type GuildIntegrationAccount struct {
	ID   string `json:"id"`
	Name string `json:"name"`
}

// A GuildEmbed stores data for a guild embed.
type GuildEmbed struct {
	Enabled   bool   `json:"enabled"`
	ChannelID string `json:"channel_id"`
}

// A UserGuildSettingsChannelOverride stores data for a channel override for a users guild settings.
type UserGuildSettingsChannelOverride struct {
	Muted                bool   `json:"muted"`
	MessageNotifications int    `json:"message_notifications"`
	ChannelID            string `json:"channel_id"`
}

// A UserGuildSettings stores data for a users guild settings.
type UserGuildSettings struct {
	SupressEveryone      bool                                `json:"suppress_everyone"`
	Muted                bool                                `json:"muted"`
	MobilePush           bool                                `json:"mobile_push"`
	MessageNotifications int                                 `json:"message_notifications"`
	GuildID              string                              `json:"guild_id"`
	ChannelOverrides     []*UserGuildSettingsChannelOverride `json:"channel_overrides"`
}

// A UserGuildSettingsEdit stores data for editing UserGuildSettings
type UserGuildSettingsEdit struct {
	SupressEveryone      bool                                         `json:"suppress_everyone"`
	Muted                bool                                         `json:"muted"`
	MobilePush           bool                                         `json:"mobile_push"`
	MessageNotifications int                                          `json:"message_notifications"`
	ChannelOverrides     map[string]*UserGuildSettingsChannelOverride `json:"channel_overrides"`
}

// An APIErrorMessage is an api error message returned from discord
type APIErrorMessage struct {
	Code    int    `json:"code"`
	Message string `json:"message"`
}

// Webhook stores the data for a webhook.
type Webhook struct {
	ID        string `json:"id"`
	GuildID   string `json:"guild_id"`
	ChannelID string `json:"channel_id"`
	User      *User  `json:"user"`
	Name      string `json:"name"`
	Avatar    string `json:"avatar"`
	Token     string `json:"token"`
}

// WebhookParams is a struct for webhook params, used in the WebhookExecute command.
type WebhookParams struct {
	Content   string          `json:"content,omitempty"`
	Username  string          `json:"username,omitempty"`
	AvatarURL string          `json:"avatar_url,omitempty"`
	TTS       bool            `json:"tts,omitempty"`
	File      string          `json:"file,omitempty"`
	Embeds    []*MessageEmbed `json:"embeds,omitempty"`
}

// MessageReaction stores the data for a message reaction.
type MessageReaction struct {
	UserID    string `json:"user_id"`
	MessageID string `json:"message_id"`
	Emoji     Emoji  `json:"emoji"`
	ChannelID string `json:"channel_id"`
}

// GatewayBotResponse stores the data for the gateway/bot response
type GatewayBotResponse struct {
	URL    string `json:"url"`
	Shards int    `json:"shards"`
}

// Constants for the different bit offsets of text channel permissions
const (
	PermissionReadMessages = 1 << (iota + 10)
	PermissionSendMessages
	PermissionSendTTSMessages
	PermissionManageMessages
	PermissionEmbedLinks
	PermissionAttachFiles
	PermissionReadMessageHistory
	PermissionMentionEveryone
	PermissionUseExternalEmojis
)

// Constants for the different bit offsets of voice permissions
const (
	PermissionVoiceConnect = 1 << (iota + 20)
	PermissionVoiceSpeak
	PermissionVoiceMuteMembers
	PermissionVoiceDeafenMembers
	PermissionVoiceMoveMembers
	PermissionVoiceUseVAD
)

// Constants for general management.
const (
	PermissionChangeNickname = 1 << (iota + 26)
	PermissionManageNicknames
	PermissionManageRoles
	PermissionManageWebhooks
	PermissionManageEmojis
)

// Constants for the different bit offsets of general permissions
const (
	PermissionCreateInstantInvite = 1 << iota
	PermissionKickMembers
	PermissionBanMembers
	PermissionAdministrator
	PermissionManageChannels
	PermissionManageServer
	PermissionAddReactions
	PermissionViewAuditLogs

	PermissionAllText = PermissionReadMessages |
		PermissionSendMessages |
		PermissionSendTTSMessages |
		PermissionManageMessages |
		PermissionEmbedLinks |
		PermissionAttachFiles |
		PermissionReadMessageHistory |
		PermissionMentionEveryone
	PermissionAllVoice = PermissionVoiceConnect |
		PermissionVoiceSpeak |
		PermissionVoiceMuteMembers |
		PermissionVoiceDeafenMembers |
		PermissionVoiceMoveMembers |
		PermissionVoiceUseVAD
	PermissionAllChannel = PermissionAllText |
		PermissionAllVoice |
		PermissionCreateInstantInvite |
		PermissionManageRoles |
		PermissionManageChannels |
		PermissionAddReactions |
		PermissionViewAuditLogs
	PermissionAll = PermissionAllChannel |
		PermissionKickMembers |
		PermissionBanMembers |
		PermissionManageServer |
		PermissionAdministrator
)

// Block contains Discord JSON Error Response codes
const (
	ErrCodeUnknownAccount     = 10001
	ErrCodeUnknownApplication = 10002
	ErrCodeUnknownChannel     = 10003
	ErrCodeUnknownGuild       = 10004
	ErrCodeUnknownIntegration = 10005
	ErrCodeUnknownInvite      = 10006
	ErrCodeUnknownMember      = 10007
	ErrCodeUnknownMessage     = 10008
	ErrCodeUnknownOverwrite   = 10009
	ErrCodeUnknownProvider    = 10010
	ErrCodeUnknownRole        = 10011
	ErrCodeUnknownToken       = 10012
	ErrCodeUnknownUser        = 10013
	ErrCodeUnknownEmoji       = 10014

	ErrCodeBotsCannotUseEndpoint  = 20001
	ErrCodeOnlyBotsCanUseEndpoint = 20002

	ErrCodeMaximumGuildsReached     = 30001
	ErrCodeMaximumFriendsReached    = 30002
	ErrCodeMaximumPinsReached       = 30003
	ErrCodeMaximumGuildRolesReached = 30005
	ErrCodeTooManyReactions         = 30010

	ErrCodeUnauthorized = 40001

	ErrCodeMissingAccess                             = 50001
	ErrCodeInvalidAccountType                        = 50002
	ErrCodeCannotExecuteActionOnDMChannel            = 50003
	ErrCodeEmbedCisabled                             = 50004
	ErrCodeCannotEditFromAnotherUser                 = 50005
	ErrCodeCannotSendEmptyMessage                    = 50006
	ErrCodeCannotSendMessagesToThisUser              = 50007
	ErrCodeCannotSendMessagesInVoiceChannel          = 50008
	ErrCodeChannelVerificationLevelTooHigh           = 50009
	ErrCodeOAuth2ApplicationDoesNotHaveBot           = 50010
	ErrCodeOAuth2ApplicationLimitReached             = 50011
	ErrCodeInvalidOAuthState                         = 50012
	ErrCodeMissingPermissions                        = 50013
	ErrCodeInvalidAuthenticationToken                = 50014
	ErrCodeNoteTooLong                               = 50015
	ErrCodeTooFewOrTooManyMessagesToDelete           = 50016
	ErrCodeCanOnlyPinMessageToOriginatingChannel     = 50019
	ErrCodeCannotExecuteActionOnSystemMessage        = 50021
	ErrCodeMessageProvidedTooOldForBulkDelete        = 50034
	ErrCodeInvalidFormBody                           = 50035
	ErrCodeInviteAcceptedToGuildApplicationsBotNotIn = 50036

	ErrCodeReactionBlocked = 90001
)
