/* eslint-env mocha */
const testDb = 'workspace/test.db'
const { promises: fs, constants: fsConstants } = require('fs')
const assert = require('assert').strict
const path = require('path')
const Datastore = require('../lib/datastore')
const Persistence = require('../lib/persistence')
const Cursor = require('../lib/cursor')
const { exists } = require('./utils.test.js')

describe('Cursor Async', function () {
  let d

  beforeEach(async () => {
    d = new Datastore({ filename: testDb })
    assert.equal(d.filename, testDb)
    assert.equal(d.inMemoryOnly, false)
    await Persistence.ensureDirectoryExistsAsync(path.dirname(testDb))
    if (await exists(testDb)) await fs.unlink(testDb)
    await d.loadDatabaseAsync()
    assert.equal(d.getAllData().length, 0)
  })

  describe('Without sorting', function () {
    beforeEach(async () => {
      await d.insertAsync({ age: 5 })
      await d.insertAsync({ age: 57 })
      await d.insertAsync({ age: 52 })
      await d.insertAsync({ age: 23 })
      await d.insertAsync({ age: 89 })
    })

    it('Without query, an empty query or a simple query and no skip or limit', async () => {
      const cursor = new Cursor(d)
      const docs = await cursor
      assert.equal(docs.length, 5)
      assert.equal(docs.filter(function (doc) { return doc.age === 5 })[0].age, 5)
      assert.equal(docs.filter(function (doc) { return doc.age === 57 })[0].age, 57)
      assert.equal(docs.filter(function (doc) { return doc.age === 52 })[0].age, 52)
      assert.equal(docs.filter(function (doc) { return doc.age === 23 })[0].age, 23)
      assert.equal(docs.filter(function (doc) { return doc.age === 89 })[0].age, 89)
      const cursor2 = new Cursor(d, {})
      const docs2 = await cursor2
      assert.equal(docs2.length, 5)
      assert.equal(docs2.filter(function (doc) { return doc.age === 5 })[0].age, 5)
      assert.equal(docs2.filter(function (doc) { return doc.age === 57 })[0].age, 57)
      assert.equal(docs2.filter(function (doc) { return doc.age === 52 })[0].age, 52)
      assert.equal(docs2.filter(function (doc) { return doc.age === 23 })[0].age, 23)
      assert.equal(docs2.filter(function (doc) { return doc.age === 89 })[0].age, 89)
      const cursor3 = new Cursor(d, { age: { $gt: 23 } })
      const docs3 = await cursor3
      assert.equal(docs3.length, 3)
      assert.equal(docs3.filter(function (doc) { return doc.age === 57 })[0].age, 57)
      assert.equal(docs3.filter(function (doc) { return doc.age === 52 })[0].age, 52)
      assert.equal(docs3.filter(function (doc) { return doc.age === 89 })[0].age, 89)
    })

    it('With an empty collection', async () => {
      await d.removeAsync({}, { multi: true })
      const cursor = new Cursor(d)
      const docs = await cursor
      assert.equal(docs.length, 0)
    })

    it('With a limit', async () => {
      const cursor = new Cursor(d)
      cursor.limit(3)
      const docs = await cursor
      assert.equal(docs.length, 3)
      // No way to predict which results are returned of course ...
    })

    it('With a skip', async () => {
      const cursor = new Cursor(d)
      const docs = await cursor.skip(2)
      assert.equal(docs.length, 3)
      // No way to predict which results are returned of course ...
    })

    it('With a limit and a skip and method chaining', async () => {
      const cursor = new Cursor(d)
      cursor.limit(4).skip(3) // Only way to know that the right number of results was skipped is if limit + skip > number of results
      const docs = await cursor
      assert.equal(docs.length, 2)
      // No way to predict which results are returned of course ...
    })
  }) // ===== End of 'Without sorting' =====

  describe('Sorting of the results', function () {
    beforeEach(async () => {
      // We don't know the order in which docs will be inserted but we ensure correctness by testing both sort orders
      await d.insertAsync({ age: 5 })
      await d.insertAsync({ age: 57 })
      await d.insertAsync({ age: 52 })
      await d.insertAsync({ age: 23 })
      await d.insertAsync({ age: 89 })
    })

    it('Using one sort', async () => {
      const cursor = new Cursor(d, {})
      cursor.sort({ age: 1 })
      const docs = await cursor
      // Results are in ascending order
      for (let i = 0; i < docs.length - 1; i += 1) {
        assert(docs[i].age < docs[i + 1].age)
      }

      cursor.sort({ age: -1 })
      const docs2 = await cursor
      // Results are in descending order
      for (let i = 0; i < docs2.length - 1; i += 1) {
        assert(docs2[i].age > docs2[i + 1].age)
      }
    })

    it('Sorting strings with custom string comparison function', async () => {
      const db = new Datastore({
        inMemoryOnly: true,
        autoload: true,
        compareStrings: function (a, b) { return a.length - b.length }
      })

      db.insertAsync({ name: 'alpha' }) // TODO was not awaited
      db.insertAsync({ name: 'charlie' }) // TODO was not awaited
      db.insertAsync({ name: 'zulu' }) // TODO was not awaited

      const docs = await db.findAsync({}).sort({ name: 1 })
      assert.equal(docs.map(x => x.name)[0], 'zulu')
      assert.equal(docs.map(x => x.name)[1], 'alpha')
      assert.equal(docs.map(x => x.name)[2], 'charlie')

      delete db.compareStrings
      const docs2 = await db.find({}).sort({ name: 1 })
      assert.equal(docs2.map(x => x.name)[0], 'alpha')
      assert.equal(docs2.map(x => x.name)[1], 'charlie')
      assert.equal(docs2.map(x => x.name)[2], 'zulu')
    })

    it('With an empty collection', async () => {
      await d.removeAsync({}, { multi: true })
      const cursor = new Cursor(d)
      cursor.sort({ age: 1 })
      const docs = await cursor
      assert.equal(docs.length, 0)
    })

    it('Ability to chain sorting and exec', async () => {
      const cursor = new Cursor(d)
      const docs = await cursor.sort({ age: 1 })
      // Results are in ascending order
      for (let i = 0; i < docs.length - 1; i += 1) {
        assert.ok(docs[i].age < docs[i + 1].age)
      }

      const cursor2 = new Cursor(d)
      const docs2 = await cursor2.sort({ age: -1 })
      // Results are in descending order
      for (let i = 0; i < docs2.length - 1; i += 1) {
        assert(docs2[i].age > docs2[i + 1].age)
      }
    })

    it('Using limit and sort', async () => {
      const cursor = new Cursor(d)
      const docs = await cursor.sort({ age: 1 }).limit(3)
      assert.equal(docs.length, 3)
      assert.equal(docs[0].age, 5)
      assert.equal(docs[1].age, 23)
      assert.equal(docs[2].age, 52)
      const cursor2 = new Cursor(d)
      const docs2 = await cursor2.sort({ age: -1 }).limit(2)
      assert.equal(docs2.length, 2)
      assert.equal(docs2[0].age, 89)
      assert.equal(docs2[1].age, 57)
    })

    it('Using a limit higher than total number of docs shouldn\'t cause an error', async () => {
      const cursor = new Cursor(d)
      const docs = await cursor.sort({ age: 1 }).limit(7)
      assert.equal(docs.length, 5)
      assert.equal(docs[0].age, 5)
      assert.equal(docs[1].age, 23)
      assert.equal(docs[2].age, 52)
      assert.equal(docs[3].age, 57)
      assert.equal(docs[4].age, 89)
    })

    it('Using limit and skip with sort', async () => {
      const cursor = new Cursor(d)
      const docs = await cursor.sort({ age: 1 }).limit(1).skip(2)
      assert.equal(docs.length, 1)
      assert.equal(docs[0].age, 52)
      const cursor2 = new Cursor(d)
      const docs2 = await cursor2.sort({ age: 1 }).limit(3).skip(1)
      assert.equal(docs2.length, 3)
      assert.equal(docs2[0].age, 23)
      assert.equal(docs2[1].age, 52)
      assert.equal(docs2[2].age, 57)
      const cursor3 = new Cursor(d)
      const docs3 = await cursor3.sort({ age: -1 }).limit(2).skip(2)
      assert.equal(docs3.length, 2)
      assert.equal(docs3[0].age, 52)
      assert.equal(docs3[1].age, 23)
    })

    it('Using too big a limit and a skip with sort', async () => {
      const cursor = new Cursor(d)
      const docs = await cursor.sort({ age: 1 }).limit(8).skip(2)
      assert.equal(docs.length, 3)
      assert.equal(docs[0].age, 52)
      assert.equal(docs[1].age, 57)
      assert.equal(docs[2].age, 89)
    })

    it('Using too big a skip with sort should return no result', async () => {
      const cursor = new Cursor(d)
      const docs = await cursor.sort({ age: 1 }).skip(5)
      assert.equal(docs.length, 0)
      const cursor2 = new Cursor(d)
      const docs2 = await cursor2.sort({ age: 1 }).skip(7)
      assert.equal(docs2.length, 0)

      const cursor3 = new Cursor(d)
      const docs3 = await cursor3.sort({ age: 1 }).limit(3).skip(7)
      assert.equal(docs3.length, 0)
      const cursor4 = new Cursor(d)
      const docs4 = await cursor4.sort({ age: 1 }).limit(6).skip(7)
      assert.equal(docs4.length, 0)
    })

    it('Sorting strings', async () => {
      await d.removeAsync({}, { multi: true })
      await d.insertAsync({ name: 'jako' })
      await d.insertAsync({ name: 'jakeb' })
      await d.insertAsync({ name: 'sue' })

      const cursor = new Cursor(d, {})
      const docs = await cursor.sort({ name: 1 })
      assert.equal(docs.length, 3)
      assert.equal(docs[0].name, 'jakeb')
      assert.equal(docs[1].name, 'jako')
      assert.equal(docs[2].name, 'sue')
      const cursor2 = new Cursor(d, {})
      const docs2 = await cursor2.sort({ name: -1 })
      assert.equal(docs2.length, 3)
      assert.equal(docs2[0].name, 'sue')
      assert.equal(docs2[1].name, 'jako')
      assert.equal(docs2[2].name, 'jakeb')
    })

    it('Sorting nested fields with dates', async () => {
      await d.removeAsync({}, { multi: true })
      const doc1 = await d.insertAsync({ event: { recorded: new Date(400) } })
      const doc2 = await d.insertAsync({ event: { recorded: new Date(60000) } })
      const doc3 = await d.insertAsync({ event: { recorded: new Date(32) } })
      const cursor = new Cursor(d, {})
      const docs = await cursor.sort({ 'event.recorded': 1 })
      assert.equal(docs.length, 3)
      assert.equal(docs[0]._id, doc3._id)
      assert.equal(docs[1]._id, doc1._id)
      assert.equal(docs[2]._id, doc2._id)

      const cursor2 = new Cursor(d, {})
      const docs2 = await cursor2.sort({ 'event.recorded': -1 })
      assert.equal(docs2.length, 3)
      assert.equal(docs2[0]._id, doc2._id)
      assert.equal(docs2[1]._id, doc1._id)
      assert.equal(docs2[2]._id, doc3._id)
    })

    it('Sorting when some fields are undefined', async () => {
      await d.removeAsync({}, { multi: true })

      await d.insertAsync({ name: 'jako', other: 2 })
      await d.insertAsync({ name: 'jakeb', other: 3 })
      await d.insertAsync({ name: 'sue' })
      await d.insertAsync({ name: 'henry', other: 4 })

      const cursor = new Cursor(d, {})
      // eslint-disable-next-line node/handle-callback-err
      const docs = await cursor.sort({ other: 1 })
      assert.equal(docs.length, 4)
      assert.equal(docs[0].name, 'sue')
      assert.equal(docs[0].other, undefined)
      assert.equal(docs[1].name, 'jako')
      assert.equal(docs[1].other, 2)
      assert.equal(docs[2].name, 'jakeb')
      assert.equal(docs[2].other, 3)
      assert.equal(docs[3].name, 'henry')
      assert.equal(docs[3].other, 4)
      const cursor2 = new Cursor(d, { name: { $in: ['suzy', 'jakeb', 'jako'] } })
      const docs2 = await cursor2.sort({ other: -1 })
      assert.equal(docs2.length, 2)
      assert.equal(docs2[0].name, 'jakeb')
      assert.equal(docs2[0].other, 3)
      assert.equal(docs2[1].name, 'jako')
      assert.equal(docs2[1].other, 2)
    })

    it('Sorting when all fields are undefined', async () => {
      await d.removeAsync({}, { multi: true })
      await d.insertAsync({ name: 'jako' })
      await d.insertAsync({ name: 'jakeb' })
      await d.insertAsync({ name: 'sue' })
      const cursor = new Cursor(d, {})
      const docs = await cursor.sort({ other: 1 })
      assert.equal(docs.length, 3)

      const cursor2 = new Cursor(d, { name: { $in: ['sue', 'jakeb', 'jakob'] } })
      const docs2 = await cursor2.sort({ other: -1 })
      assert.equal(docs2.length, 2)
    })

    it('Multiple consecutive sorts', async () => {
      await d.removeAsync({}, { multi: true })

      await d.insertAsync({ name: 'jako', age: 43, nid: 1 })
      await d.insertAsync({ name: 'jakeb', age: 43, nid: 2 })
      await d.insertAsync({ name: 'sue', age: 12, nid: 3 })
      await d.insertAsync({ name: 'zoe', age: 23, nid: 4 })
      await d.insertAsync({ name: 'jako', age: 35, nid: 5 })
      const cursor = new Cursor(d, {})
      // eslint-disable-next-line node/handle-callback-err
      const docs = await cursor.sort({ name: 1, age: -1 })
      assert.equal(docs.length, 5)

      assert.equal(docs[0].nid, 2)
      assert.equal(docs[1].nid, 1)
      assert.equal(docs[2].nid, 5)
      assert.equal(docs[3].nid, 3)
      assert.equal(docs[4].nid, 4)
      const cursor2 = new Cursor(d, {})
      const docs2 = await cursor2.sort({ name: 1, age: 1 })
      assert.equal(docs2.length, 5)

      assert.equal(docs2[0].nid, 2)
      assert.equal(docs2[1].nid, 5)
      assert.equal(docs2[2].nid, 1)
      assert.equal(docs2[3].nid, 3)
      assert.equal(docs2[4].nid, 4)
      const cursor3 = new Cursor(d, {})
      const docs3 = await cursor3.sort({ age: 1, name: 1 })
      assert.equal(docs3.length, 5)

      assert.equal(docs3[0].nid, 3)
      assert.equal(docs3[1].nid, 4)
      assert.equal(docs3[2].nid, 5)
      assert.equal(docs3[3].nid, 2)
      assert.equal(docs3[4].nid, 1)

      const cursor4 = new Cursor(d, {})
      const docs4 = await cursor4.sort({ age: 1, name: -1 })
      assert.equal(docs4.length, 5)

      assert.equal(docs4[0].nid, 3)
      assert.equal(docs4[1].nid, 4)
      assert.equal(docs4[2].nid, 5)
      assert.equal(docs4[3].nid, 1)
      assert.equal(docs4[4].nid, 2)
    })

    it('Similar data, multiple consecutive sorts', async () => {
      let id
      const companies = ['acme', 'milkman', 'zoinks']
      const entities = []
      await d.removeAsync({}, { multi: true })
      id = 1
      for (let i = 0; i < companies.length; i++) {
        for (let j = 5; j <= 100; j += 5) {
          entities.push({
            company: companies[i],
            cost: j,
            nid: id
          })
          id++
        }
      }
      await Promise.all(entities.map(entity => d.insertAsync(entity)))
      const cursor = new Cursor(d, {})
      const docs = await cursor.sort({ company: 1, cost: 1 })
      assert.equal(docs.length, 60)

      for (let i = 0; i < docs.length; i++) {
        assert.equal(docs[i].nid, i + 1)
      }
    })
  }) // ===== End of 'Sorting' =====

  describe('Projections', function () {
    let doc1
    let doc2
    let doc3
    let doc4
    let doc0

    beforeEach(async () => {
      // We don't know the order in which docs will be inserted but we ensure correctness by testing both sort orders
      doc0 = await d.insertAsync({ age: 5, name: 'Jo', planet: 'B', toys: { bebe: true, ballon: 'much' } })
      doc1 = await d.insertAsync({ age: 57, name: 'Louis', planet: 'R', toys: { ballon: 'yeah', bebe: false } })
      doc2 = await d.insertAsync({ age: 52, name: 'Grafitti', planet: 'C', toys: { bebe: 'kind of' } })
      doc3 = await d.insertAsync({ age: 23, name: 'LM', planet: 'S' })
      doc4 = await d.insertAsync({ age: 89, planet: 'Earth' })
    })

    it('Takes all results if no projection or empty object given', async () => {
      const cursor = new Cursor(d, {})
      cursor.sort({ age: 1 }) // For easier finding
      const docs = await cursor
      assert.equal(docs.length, 5)
      assert.deepStrictEqual(docs[0], doc0)
      assert.deepStrictEqual(docs[1], doc3)
      assert.deepStrictEqual(docs[2], doc2)
      assert.deepStrictEqual(docs[3], doc1)
      assert.deepStrictEqual(docs[4], doc4)

      cursor.projection({})
      const docs2 = await cursor
      assert.equal(docs2.length, 5)
      assert.deepStrictEqual(docs2[0], doc0)
      assert.deepStrictEqual(docs2[1], doc3)
      assert.deepStrictEqual(docs2[2], doc2)
      assert.deepStrictEqual(docs2[3], doc1)
      assert.deepStrictEqual(docs2[4], doc4)
    })

    it('Can take only the expected fields', async () => {
      const cursor = new Cursor(d, {})
      cursor.sort({ age: 1 }) // For easier finding
      cursor.projection({ age: 1, name: 1 })
      const docs = await cursor
      assert.equal(docs.length, 5)
      // Takes the _id by default
      assert.deepStrictEqual(docs[0], { age: 5, name: 'Jo', _id: doc0._id })
      assert.deepStrictEqual(docs[1], { age: 23, name: 'LM', _id: doc3._id })
      assert.deepStrictEqual(docs[2], { age: 52, name: 'Grafitti', _id: doc2._id })
      assert.deepStrictEqual(docs[3], { age: 57, name: 'Louis', _id: doc1._id })
      assert.deepStrictEqual(docs[4], { age: 89, _id: doc4._id }) // No problems if one field to take doesn't exist

      cursor.projection({ age: 1, name: 1, _id: 0 })
      const docs2 = await cursor
      assert.equal(docs2.length, 5)
      assert.deepStrictEqual(docs2[0], { age: 5, name: 'Jo' })
      assert.deepStrictEqual(docs2[1], { age: 23, name: 'LM' })
      assert.deepStrictEqual(docs2[2], { age: 52, name: 'Grafitti' })
      assert.deepStrictEqual(docs2[3], { age: 57, name: 'Louis' })
      assert.deepStrictEqual(docs2[4], { age: 89 }) // No problems if one field to take doesn't exist
    })

    it('Can omit only the expected fields', async () => {
      const cursor = new Cursor(d, {})
      cursor.sort({ age: 1 }) // For easier finding
      cursor.projection({ age: 0, name: 0 })
      const docs = await cursor
      assert.equal(docs.length, 5)
      // Takes the _id by default
      assert.deepStrictEqual(docs[0], { planet: 'B', _id: doc0._id, toys: { bebe: true, ballon: 'much' } })
      assert.deepStrictEqual(docs[1], { planet: 'S', _id: doc3._id })
      assert.deepStrictEqual(docs[2], { planet: 'C', _id: doc2._id, toys: { bebe: 'kind of' } })
      assert.deepStrictEqual(docs[3], { planet: 'R', _id: doc1._id, toys: { bebe: false, ballon: 'yeah' } })
      assert.deepStrictEqual(docs[4], { planet: 'Earth', _id: doc4._id })

      cursor.projection({ age: 0, name: 0, _id: 0 })
      const docs2 = await cursor
      assert.equal(docs2.length, 5)
      assert.deepStrictEqual(docs2[0], { planet: 'B', toys: { bebe: true, ballon: 'much' } })
      assert.deepStrictEqual(docs2[1], { planet: 'S' })
      assert.deepStrictEqual(docs2[2], { planet: 'C', toys: { bebe: 'kind of' } })
      assert.deepStrictEqual(docs2[3], { planet: 'R', toys: { bebe: false, ballon: 'yeah' } })
      assert.deepStrictEqual(docs2[4], { planet: 'Earth' })
    })

    it('Cannot use both modes except for _id', async () => {
      const cursor = new Cursor(d, {})
      cursor.sort({ age: 1 }) // For easier finding
      cursor.projection({ age: 1, name: 0 })
      await assert.rejects(() => cursor)

      cursor.projection({ age: 1, _id: 0 })
      const docs = await cursor
      assert.deepStrictEqual(docs[0], { age: 5 })
      assert.deepStrictEqual(docs[1], { age: 23 })
      assert.deepStrictEqual(docs[2], { age: 52 })
      assert.deepStrictEqual(docs[3], { age: 57 })
      assert.deepStrictEqual(docs[4], { age: 89 })

      cursor.projection({ age: 0, toys: 0, planet: 0, _id: 1 })
      const docs2 = await cursor
      assert.deepStrictEqual(docs2[0], { name: 'Jo', _id: doc0._id })
      assert.deepStrictEqual(docs2[1], { name: 'LM', _id: doc3._id })
      assert.deepStrictEqual(docs2[2], { name: 'Grafitti', _id: doc2._id })
      assert.deepStrictEqual(docs2[3], { name: 'Louis', _id: doc1._id })
      assert.deepStrictEqual(docs2[4], { _id: doc4._id })
    })

    it('Projections on embedded documents - omit type', async () => {
      const cursor = new Cursor(d, {})
      cursor.sort({ age: 1 }) // For easier finding
      cursor.projection({ name: 0, planet: 0, 'toys.bebe': 0, _id: 0 })
      const docs = await cursor
      assert.deepStrictEqual(docs[0], { age: 5, toys: { ballon: 'much' } })
      assert.deepStrictEqual(docs[1], { age: 23 })
      assert.deepStrictEqual(docs[2], { age: 52, toys: {} })
      assert.deepStrictEqual(docs[3], { age: 57, toys: { ballon: 'yeah' } })
      assert.deepStrictEqual(docs[4], { age: 89 })
    })

    it('Projections on embedded documents - pick type', async () => {
      const cursor = new Cursor(d, {})
      cursor.sort({ age: 1 }) // For easier finding
      cursor.projection({ name: 1, 'toys.ballon': 1, _id: 0 })
      const docs = await cursor
      assert.deepStrictEqual(docs[0], { name: 'Jo', toys: { ballon: 'much' } })
      assert.deepStrictEqual(docs[1], { name: 'LM' })
      assert.deepStrictEqual(docs[2], { name: 'Grafitti' })
      assert.deepStrictEqual(docs[3], { name: 'Louis', toys: { ballon: 'yeah' } })
      assert.deepStrictEqual(docs[4], {})
    })
  }) // ==== End of 'Projections' ====
})