const chai = require('chai');
const chaiHttp = require('chai-http');
const express = require('express');
import { expect } from 'chai';
import { SetupApp } from '../../../app';
import { ReferenceDatabase } from '../../reference_model/DBReferenceModel';
import { randomDBAction, RandomDBActionDistribution, DBActionType, applyReferenceDBAction, applyRealDBAction, DBAction } from '../../reference_model/randomGen';
import * as helpers from '../helpers';
import seedrandom from 'seedrandom';
import { AlbumWithRefsWithId, Artist, ArtistWithRefsWithId, TagWithRefsWithId, TrackWithRefs, TrackWithRefsWithId } from '../../../../client/src/api/api';
import sampleDB from '../sampleDB';
let stringify = require('json-stringify-deterministic');

let _ = require('lodash');
let tmp = require('tmp');
let fs = require('fs');

async function init() {
    chai.use(chaiHttp);
    const app = express();
    const knex = await helpers.initTestDB();

    SetupApp(app, knex, '');

    var agent = chai.request.agent(app);
    return agent;
}

// Alters a response from a real or mock DB so that they can be deep-compared
// and only non-trivial differences trigger an error.
function normalizeResponse(response: any) {
    let r: any = _.cloneDeep(response);
    if (r && 'id' in r) {
        r.id = '<redacted>';
    }
    return r;
}

// Alters a database export / reference database model so that it can be compared
// to another so that only non-trivial differences trigger an error.
function normalizeDB(oldDb: ReferenceDatabase) {
    let db: ReferenceDatabase = _.cloneDeep(oldDb);


    // Apply a deterministic sorting.
    // TODO: sorting by name is not deterministic.
    for (const userId in db) {
        db[userId].tracks.sort((a: any, b: any) => a.name.localeCompare(b.name))
        db[userId].albums.sort((a: any, b: any) => a.name.localeCompare(b.name))
        db[userId].artists.sort((a: any, b: any) => a.name.localeCompare(b.name))
        db[userId].tags.sort((a: any, b: any) => a.name.localeCompare(b.name))
    }

    // Re-map IDs.
    interface IDMap {
        map: Map<number, number>,
        highestId: number,
    };
    let trackMap: IDMap = { map: new Map<number, number>(), highestId: 0 };
    let albumMap: IDMap = { map: new Map<number, number>(), highestId: 0 };
    let artistMap: IDMap = { map: new Map<number, number>(), highestId: 0 };
    let tagMap: IDMap = { map: new Map<number, number>(), highestId: 0 };
    let remapId = (id: number, map: IDMap) => {
        if (map.map.has(id)) { return map.map.get(id) as number; }
        let newId: number = map.highestId + 1;
        map.map.set(id, newId);
        map.highestId = newId;
        return newId;
    }
    for (const userId in db) {
        // First remap the IDs only, ignoring references
        db[userId].tracks.forEach((x: TrackWithRefsWithId) => { console.log("X:", x); x.id = remapId(x.id, trackMap); });
        db[userId].albums.forEach((x: AlbumWithRefsWithId) => { x.id = remapId(x.id, albumMap); })
        db[userId].artists.forEach((x: ArtistWithRefsWithId) => { x.id = remapId(x.id, artistMap); })
        db[userId].tags.forEach((x: TagWithRefsWithId) => { x.id = remapId(x.id, tagMap); })
    }
    for (const userId in db) {
        // Now remap the references.
        db[userId].tracks.forEach((x: TrackWithRefsWithId) => {
            x.tagIds = x.tagIds.map((id: number) => remapId(id, tagMap));
            x.artistIds = x.artistIds.map((id: number) => remapId(id, artistMap));
            x.albumId = x.albumId ? remapId(x.albumId, albumMap) : null;
        });
        db[userId].albums.forEach((x: AlbumWithRefsWithId) => {
            x.tagIds = x.tagIds.map((id: number) => remapId(id, tagMap));
            x.artistIds = x.artistIds.map((id: number) => remapId(id, artistMap));
            x.trackIds = x.trackIds.map((id: number) => remapId(id, trackMap));
        });
        db[userId].artists.forEach((x: ArtistWithRefsWithId) => {
            x.tagIds = x.tagIds.map((id: number) => remapId(id, tagMap));
            x.albumIds = x.albumIds.map((id: number) => remapId(id, albumMap));
            x.trackIds = x.trackIds.map((id: number) => remapId(id, trackMap));
        });
        db[userId].tags.forEach((x: TagWithRefsWithId) => {
            x.parentId = x.parentId ? remapId(x.parentId, tagMap) : null;
        });
    }

    return db;
}

describe('Randomized model-based DB back-end tests', () => {
    it('all succeed', async done => {
        let req = await init();
        let actionTrace: DBAction[] = [];

        let seed: string = process.env.TEST_RANDOM_SEED || Math.random().toFixed(5).toString();
        console.log(`Test random seed: '${seed}'`)

        try {
            // Create a reference DB
            let refDB: ReferenceDatabase = _.cloneDeep(sampleDB);

            // Prime the real DB
            // First, create a user and log in.
            await helpers.createUser(req, "someone@email.com", "password1A!", 200);
            await helpers.login(req, "someone@email.com", "password1A!", 200);
            // Import the starting DB.
            await helpers.importDB(req, refDB[1]);

            // Check that we are starting from an equal situation
            let refState = normalizeDB(refDB);
            let realState = normalizeDB({
                [1]: (await helpers.getExport(req)).body,
            });
            expect(realState).to.deep.equal(refState);

            // Start doing some random changes, checking the state after each step.
            let rng = seedrandom(seed);
            let dist: RandomDBActionDistribution = {
                type: new Map([
                    [DBActionType.CreateTrack, 0.7],
                    [DBActionType.DeleteTrack, 0.3]
                ]),
                userId: new Map([[1, 1.0]]),
                createTrackParams: {
                    linkAlbum: new Map<boolean | 'nonexistent', number>([[false, 0.45], [true, 0.45], ['nonexistent', 0.1]]),
                    linkTags: {
                        numValid: new Map([[0, 1.0]]),
                        numInvalid: new Map([[0, 0.9], [1, 0.05], [2, 0.05]]),
                    },
                    linkArtists: {
                        numValid: new Map([[0, 1.0]]),
                        numInvalid: new Map([[0, 0.9], [1, 0.05], [2, 0.05]]),
                    },
                },
                deleteTrackParams: {
                    validTrack: new Map([[false, 0.2], [true, 0.8]])
                }
            }

            for (let i = 0; i < 30; i++) {
                let action = randomDBAction(
                    refDB,
                    rng,
                    dist
                );
                actionTrace.push(action);
                console.log("Testing action: ", action);
                let { response: refResponse, status: refStatus } = applyReferenceDBAction(action, refDB);
                let { response: realResponse, status: realStatus } = await applyRealDBAction(action, req);

                // Compare the response and status.
                expect(normalizeResponse(realResponse)).to.deep.equal(normalizeResponse(refResponse));
                expect(realStatus).to.equal(refStatus);

                // Compare the database state after the action.
                let refState = normalizeDB(refDB);
                let realState = normalizeDB({
                    [1]: (await helpers.getExport(req)).body,
                });
                expect(realState).to.deep.equal(refState);
            }
        } catch (e) {
            // When catching a comparison error, add and dump various states to files for debugging.
            e.actionTrace = actionTrace;
            e.startingDB = normalizeDB(sampleDB);
            e.testSeed = seed;
            if (e.actual && e.expected) {
                e.actualDump = tmp.tmpNameSync();
                e.expectedDump = tmp.tmpNameSync();
                e.actionTraceDump = tmp.tmpNameSync();
                e.startingDBDump = tmp.tmpNameSync();
                fs.writeFileSync(e.actualDump, stringify(e.actual, { space: '  ' }));
                fs.writeFileSync(e.expectedDump, stringify(e.expected, { space: '  ' }));
                fs.writeFileSync(e.actionTraceDump, stringify(e.actionTrace, { space: '  ' }));
                fs.writeFileSync(e.startingDBDump, stringify(e.startingDB, { space: '  ' }));

                console.log(
                    "A comparison error occurred. Wrote compared values to temporary files for debugging:\n"
                    + `  actual: ${e.actualDump}\n`
                    + `  expected: ${e.expectedDump}\n`
                    + `  DB action trace: ${e.actionTraceDump}\n`
                    + `  Starting DB: ${e.startingDBDump}`
                );
            }
            throw e;
        } finally {
            req.close();
            done();
        }
    });
});