// TODO: this file is located in the client src folder because
// otherwise, Create React App will refuse to compile it.
// Putting it in the server folder or in its own folder makes more sense.

// This file represents the API interface for Mudbase's back-end.
// Each endpoint is described by its endpoint address,
// a request structure, a response structure and
// a checking function which determines request validity.

export enum ItemType {
    Song = 0,
    Artist,
    Album,
    Tag
}

export interface ArtistDetails {
    artistId: Number,
    name: String,
    storeLinks?: String[],
}
export function isArtistDetails(q: any): q is ArtistDetails {
    return 'artistId' in q;
}
export interface TagDetails {
    tagId: Number,
    name: String,
    parent?: TagDetails,
    storeLinks?: String[],
}
export function isTagDetails(q: any): q is TagDetails {
    return 'tagId' in q;
}
export interface RankingDetails {
    rankingId: Number,
    type: ItemType, // The item type being ranked
    rankedId: Number, // The item being ranked
    context: ArtistDetails | TagDetails,
    value: Number, // The ranking (higher = better)
}
export function isRankingDetails(q: any): q is RankingDetails {
    return 'rankingId' in q;
}
export interface SongDetails {
    songId: Number,
    title: String,
    artists?: ArtistDetails[],
    tags?: TagDetails[],
    storeLinks?: String[],
    rankings?: RankingDetails[],
}
export function isSongDetails(q: any): q is SongDetails {
    return 'songId' in q;
}

// Query for items (POST).
export const QueryEndpoint = '/query';
export enum QueryElemOp {
    And = "AND",
    Or = "OR",
}
export enum QueryFilterOp {
    Eq = "EQ",
    Ne = "NE",
    In = "IN",
    NotIn = "NOTIN",
    Like = "LIKE",
}
export enum QueryElemProperty {
    songTitle = "songTitle",
    songId = "songId",
    artistName = "artistName",
    albumName = "albumName",
}
export enum OrderBy {
    Name = 0
}
export interface QueryElem {
    prop?: QueryElemProperty,
    propOperand?: any,
    propOperator?: QueryFilterOp,
    children?: QueryElem[]
    childrenOperator?: QueryElemOp,
}
export interface Ordering {
    orderBy: OrderBy,
    ascending: boolean,
}
export interface Query extends QueryElem { }
export interface QueryRequest {
    query: Query,
    songOffset: number,
    songLimit: number,
    artistOffset: number,
    artistLimit: number,
    tagOffset: number,
    tagLimit: number,
    ordering: Ordering,
}
export interface QueryResponse {
    songs: SongDetails[],
    artists: ArtistDetails[],
    tags: TagDetails[],
}
export function checkQueryElem(elem: any): boolean {
    if (elem.childrenOperator && elem.children) {
        elem.children.forEach((child: any) => {
            if (!checkQueryElem(child)) {
                return false;
            }
        });
    }
    return (elem.childrenOperator && elem.children) ||
        (elem.prop && elem.propOperand && elem.propOperator) ||
        Object.keys(elem).length == 0;
}
export function checkQueryRequest(req: any): boolean {
    return 'query' in req
        && 'songOffset' in req
        && 'songLimit' in req
        && 'artistOffset' in req
        && 'artistLimit' in req
        && 'tagOffset' in req
        && 'tagLimit' in req
        && checkQueryElem(req.query);
}

// Get song details (GET).
export const SongDetailsEndpoint = '/song/:id';
export interface SongDetailsRequest { }
export interface SongDetailsResponse {
    title: String,
    storeLinks: String[],
    artistIds: Number[],
    albumIds: Number[],
    tagIds: Number[],
}
export function checkSongDetailsRequest(req: any): boolean {
    return true;
}

// Get artist details (GET).
export const ArtistDetailsEndpoint = '/artist/:id';
export interface ArtistDetailsRequest { }
export interface ArtistDetailsResponse {
    name: String,
    tagIds: Number[],
    storeLinks: String[],
}
export function checkArtistDetailsRequest(req: any): boolean {
    return true;
}

// Create a new song (POST).
export const CreateSongEndpoint = '/song';
export interface CreateSongRequest {
    title: String;
    artistIds?: Number[];
    albumIds?: Number[];
    tagIds?: Number[];
    storeLinks?: String[];
}
export interface CreateSongResponse {
    id: Number;
}
export function checkCreateSongRequest(req: any): boolean {
    return "body" in req &&
        "title" in req.body;
}

// Modify an existing song (PUT).
export const ModifySongEndpoint = '/song/:id';
export interface ModifySongRequest {
    title?: String;
    artistIds?: Number[];
    albumIds?: Number[];
    tagIds?: Number[];
    storeLinks?: String[];
}
export interface ModifySongResponse { }
export function checkModifySongRequest(req: any): boolean {
    return true;
}

// Create a new artist (POST).
export const CreateArtistEndpoint = '/artist';
export interface CreateArtistRequest {
    name: String;
    tagIds?: Number[];
    storeLinks?: String[];
}
export interface CreateArtistResponse {
    id: Number;
}
export function checkCreateArtistRequest(req: any): boolean {
    return "body" in req &&
        "name" in req.body;
}

// Modify an existing artist (PUT).
export const ModifyArtistEndpoint = '/artist/:id';
export interface ModifyArtistRequest {
    name?: String,
    tagIds?: Number[];
    storeLinks?: String[],
}
export interface ModifyArtistResponse { }
export function checkModifyArtistRequest(req: any): boolean {
    return true;
}

// Create a new tag (POST).
export const CreateTagEndpoint = '/tag';
export interface CreateTagRequest {
    name: String;
    parentId?: Number;
}
export interface CreateTagResponse {
    id: Number;
}
export function checkCreateTagRequest(req: any): boolean {
    return "body" in req &&
        "name" in req.body;
}

// Modify an existing tag (PUT).
export const ModifyTagEndpoint = '/tag/:id';
export interface ModifyTagRequest {
    name?: String,
    parentId?: Number;
}
export interface ModifyTagResponse { }
export function checkModifyTagRequest(req: any): boolean {
    return true;
}

// Get tag details (GET).
export const TagDetailsEndpoint = '/tag/:id';
export interface TagDetailsRequest { }
export interface TagDetailsResponse {
    name: String,
    parentId?: Number,
}
export function checkTagDetailsRequest(req: any): boolean {
    return true;
}