package state

import (
	"errors"

	"github.com/diamondburned/arikawa/discord"
)

// Store is the state storage. It should handle mutex itself, and it should only
// concern itself with the local state.
type Store interface {
	StoreGetter
	StoreModifier
}

type StoreMe interface {
	Me() (*discord.User, error)
	MyselfSet(me *discord.User) error
}

type StoreChannel interface {
	Channel(id discord.Snowflake) (*discord.Channel, error)
	Channels(guildID discord.Snowflake) ([]discord.Channel, error)
	PrivateChannels() ([]discord.Channel, error)

	// ChannelSet should switch on Type to know if it's a private channel or
	// not.
	ChannelSet(*discord.Channel) error
	ChannelRemove(*discord.Channel) error
}

type StoreEmoji interface {
	Emoji(guildID, emojiID discord.Snowflake) (*discord.Emoji, error)
	Emojis(guildID discord.Snowflake) ([]discord.Emoji, error)
	EmojiSet(guildID discord.Snowflake, emojis []discord.Emoji) error
}

type StoreGuild interface {
	Guild(id discord.Snowflake) (*discord.Guild, error)
	Guilds() ([]discord.Guild, error)
	GuildSet(*discord.Guild) error
	GuildRemove(id discord.Snowflake) error
}

type StoreMember interface {
	Member(guildID, userID discord.Snowflake) (*discord.Member, error)
	Members(guildID discord.Snowflake) ([]discord.Member, error)
	MemberSet(guildID discord.Snowflake, member *discord.Member) error
	MemberRemove(guildID, userID discord.Snowflake) error
}

type StoreMessage interface {
	Message(channelID, messageID discord.Snowflake) (*discord.Message, error)
	Messages(channelID discord.Snowflake) ([]discord.Message, error)
	MaxMessages() int // used to know if the state is filled or not.
	MessageSet(*discord.Message) error
	MessageRemove(channelID, messageID discord.Snowflake) error
}

type StorePresence interface {
	// These don't get fetched from the API, it's Gateway only.
	Presence(guildID, userID discord.Snowflake) (*discord.Presence, error)
	Presences(guildID discord.Snowflake) ([]discord.Presence, error)
	PresenceSet(guildID discord.Snowflake, presence *discord.Presence) error
	PresenceRemove(guildID, userID discord.Snowflake) error
}

// All methods in StoreGetter will be wrapped by the State. If the State can't
// find anything in the storage, it will call the API itself and automatically
// add what's missing into the storage.
//
// Methods that return with a slice should pay attention to race conditions that
// would mutate the underlying slice (and as a result the returned slice as
// well). The best way to avoid this is to copy the whole slice, like
// DefaultStore does.
type StoreGetter interface {



	Role(guildID, roleID discord.Snowflake) (*discord.Role, error)
	Roles(guildID discord.Snowflake) ([]discord.Role, error)
}

type StoreModifier interface {


	RoleSet(guildID discord.Snowflake, role *discord.Role) error
	RoleRemove(guildID, roleID discord.Snowflake) error

	// This should reset all the state to zero/null.
	Reset() error
}

// ErrStoreNotFound is an error that a store can use to return when something
// isn't in the storage. There is no strict restrictions on what uses this (the
// default one does, though), so be advised.
var ErrStoreNotFound = errors.New("item not found in store")