// 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"
	"reflect"
	"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

	// 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

	// Exposed but should not be modified by User.

	// Whether the Data Websocket is ready
	DataReady bool

	// Whether the Voice Websocket is ready
	VoiceReady bool

	// Whether the UDP Connection is ready
	UDPReady bool

	// 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

	handlersMu sync.RWMutex
	// This is a mapping of event struct to a reflected value
	// for event handlers.
	// We store the reflected value instead of the function
	// reference as it is more performant, instead of re-reflecting
	// the function each event.
	handlers map[interface{}][]reflect.Value

	// The websocket connection.
	wsConn *websocket.Conn

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

	// used to deal with rate limits
	// may switch to slices later
	// TODO: performance test map vs slices
	rateLimit rateLimitMutex

	// sequence tracks the current gateway api websocket sequence number
	sequence int

	// 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
}

type rateLimitMutex struct {
	sync.Mutex
	url map[string]*sync.Mutex
	// bucket map[string]*sync.Mutex // TODO :)
}

// A Resumed struct holds the data received in a RESUMED event
type Resumed struct {
	HeartbeatInterval time.Duration `json:"heartbeat_interval"`
	Trace             []string      `json:"_trace"`
}

// 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 string   `json:"created_at"` // TODO make timestamp
	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"`
}

// 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                 string                 `json:"type"`
	LastMessageID        string                 `json:"last_message_id"`
	Position             int                    `json:"position"`
	Bitrate              int                    `json:"bitrate"`
	IsPrivate            bool                   `json:"is_private"`
	Recipient            *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"`
}

// 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                    string            `json:"joined_at"` // make this a timestamp
	Splash                      string            `json:"splash"`
	AfkTimeout                  int               `json:"afk_timeout"`
	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 GuildParams stores all the data needed to update discord guild settings
type GuildParams struct {
	Name              string             `json:"name"`
	Region            string             `json:"region"`
	VerificationLevel *VerificationLevel `json:"verification_level"`
}

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

// 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 string `json:"status"`
	Game   *Game  `json:"game"`
}

// 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"`
}

// 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 User stores all data for an individual Discord user.
type User struct {
	ID            string `json:"id"`
	Email         string `json:"email"`
	Username      string `json:"username"`
	Avatar        string `json:"Avatar"`
	Discriminator string `json:"discriminator"`
	Token         string `json:"token"`
	Verified      bool   `json:"verified"`
	MFAEnabled    bool   `json:"mfa_enabled"`
	Bot           bool   `json:"bot"`
}

// 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"`
	AllowEmailFriendRequest bool               `json:"allow_email_friend_request"`
	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"`
}

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

// An Event provides a basic initial struct for all websocket event.
type Event struct {
	Operation int             `json:"op"`
	Sequence  int             `json:"s"`
	Type      string          `json:"t"`
	RawData   json.RawMessage `json:"d"`
	Struct    interface{}     `json:"-"`
}

// A Ready stores all data for the websocket READY event.
type Ready struct {
	Version           int           `json:"v"`
	SessionID         string        `json:"session_id"`
	HeartbeatInterval time.Duration `json:"heartbeat_interval"`
	User              *User         `json:"user"`
	ReadState         []*ReadState  `json:"read_state"`
	PrivateChannels   []*Channel    `json:"private_channels"`
	Guilds            []*Guild      `json:"guilds"`

	// Undocumented fields
	Settings          *Settings            `json:"user_settings"`
	UserGuildSettings []*UserGuildSettings `json:"user_guild_settings"`
	Relationships     []*Relationship      `json:"relationships"`
	Presences         []*Presence          `json:"presences"`
}

// 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"`
}

// A TypingStart stores data for the typing start websocket event.
type TypingStart struct {
	UserID    string `json:"user_id"`
	ChannelID string `json:"channel_id"`
	Timestamp int    `json:"timestamp"`
}

// A PresenceUpdate stores data for the presence update websocket event.
type PresenceUpdate struct {
	Presence
	GuildID string   `json:"guild_id"`
	Roles   []string `json:"roles"`
}

// A MessageAck stores data for the message ack websocket event.
type MessageAck struct {
	MessageID string `json:"message_id"`
	ChannelID string `json:"channel_id"`
}

// A GuildIntegrationsUpdate stores data for the guild integrations update
// websocket event.
type GuildIntegrationsUpdate struct {
	GuildID string `json:"guild_id"`
}

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

// A GuildRoleDelete stores data for the guild role delete websocket event.
type GuildRoleDelete struct {
	RoleID  string `json:"role_id"`
	GuildID string `json:"guild_id"`
}

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

// A GuildEmojisUpdate stores data for a guild emoji update event.
type GuildEmojisUpdate struct {
	GuildID string   `json:"guild_id"`
	Emojis  []*Emoji `json:"emojis"`
}

// 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"`
}

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

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

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

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