/*
 * decaffeinate suggestions:
 * DS102: Remove unnecessary code created because of implicit returns
 * Full docs: https://github.com/decaffeinate/decaffeinate/blob/master/docs/suggestions.md
 */
const sinon = require('sinon');
const chai = require('chai');
const should = chai.should();
const { expect } = chai;
const modulePath = "../../../../app/js/DiffManager.js";
const SandboxedModule = require('sandboxed-module');

describe("DiffManager", function() {
	beforeEach(function() {
		this.DiffManager = SandboxedModule.require(modulePath, { requires: {
			"logger-sharelatex": (this.logger = { log: sinon.stub(), error: sinon.stub(), warn: sinon.stub() }),
			"./UpdatesManager": (this.UpdatesManager = {}),
			"./DocumentUpdaterManager": (this.DocumentUpdaterManager = {}),
			"./DiffGenerator": (this.DiffGenerator = {})
		}
	});
		this.callback = sinon.stub();
		this.from = new Date();
		this.to = new Date(Date.now() + 10000);
		this.project_id = "mock-project-id";
		return this.doc_id = "mock-doc-id";
	});

	describe("getLatestDocAndUpdates", function() {
		beforeEach(function() {
			this.content = "hello world";
			this.version = 42;
			this.updates = [ "mock-update-1", "mock-update-2" ];

			this.DocumentUpdaterManager.getDocument = sinon.stub().callsArgWith(2, null, this.content, this.version);
			return this.UpdatesManager.getDocUpdatesWithUserInfo = sinon.stub().callsArgWith(3, null, this.updates);
		});

		describe("with a fromVersion", function() {
			beforeEach(function() {
				return this.DiffManager.getLatestDocAndUpdates(this.project_id, this.doc_id, this.from, this.callback);
			});

			it("should get the latest version of the doc", function() {
				return this.DocumentUpdaterManager.getDocument
					.calledWith(this.project_id, this.doc_id)
					.should.equal(true);
			});

			it("should get the latest updates", function() {
				return this.UpdatesManager.getDocUpdatesWithUserInfo
					.calledWith(this.project_id, this.doc_id, {from: this.from})
					.should.equal(true);
			});

			return it("should call the callback with the content, version and updates", function() {
				return this.callback.calledWith(null, this.content, this.version, this.updates).should.equal(true);
			});
		});

		return describe("with no fromVersion", function() {
			beforeEach(function() {
				return this.DiffManager.getLatestDocAndUpdates(this.project_id, this.doc_id, null, this.callback);
			});

			it("should get the latest version of the doc", function() {
				return this.DocumentUpdaterManager.getDocument
					.calledWith(this.project_id, this.doc_id)
					.should.equal(true);
			});

			it("should not get the latest updates", function() {
				return this.UpdatesManager.getDocUpdatesWithUserInfo
					.called.should.equal(false);
			});

			return it("should call the callback with the content, version and blank updates", function() {
				return this.callback.calledWith(null, this.content, this.version, []).should.equal(true);
			});
		});
	});
			

	describe("getDiff", function() {
		beforeEach(function() {
			this.content = "hello world";
			// Op versions are the version they were applied to, so doc is always one version
			// ahead.s
			this.version = 43;
			this.updates = [
				{ op: "mock-4", v: 42, meta: { start_ts: new Date(this.to.getTime() + 20)} },
				{ op: "mock-3", v: 41, meta: { start_ts: new Date(this.to.getTime() + 10)} },
				{ op: "mock-2", v: 40, meta: { start_ts: new Date(this.to.getTime() - 10)} },
				{ op: "mock-1", v: 39, meta: { start_ts: new Date(this.to.getTime() - 20)} }
			];
			this.fromVersion = 39;
			this.toVersion = 40;
			this.diffed_updates = this.updates.slice(2);
			this.rewound_content = "rewound-content";
			return this.diff = [ {u: "mock-diff"} ];});
			
		describe("with matching versions", function() {
			beforeEach(function() {
				this.DiffManager.getDocumentBeforeVersion = sinon.stub().callsArgWith(3, null, this.rewound_content, this.updates);
				this.DiffGenerator.buildDiff = sinon.stub().returns(this.diff);
				return this.DiffManager.getDiff(this.project_id, this.doc_id, this.fromVersion, this.toVersion, this.callback);
			});

			it("should get the latest doc and version with all recent updates", function() {
				return this.DiffManager.getDocumentBeforeVersion
					.calledWith(this.project_id, this.doc_id, this.fromVersion)
					.should.equal(true);
			});

			it("should generate the diff", function() {
				return this.DiffGenerator.buildDiff
					.calledWith(this.rewound_content, this.diffed_updates.slice().reverse())
					.should.equal(true);
			});

			return it("should call the callback with the diff", function() {
				return this.callback.calledWith(null, this.diff).should.equal(true);
			});
		});

		return describe("when the updates are inconsistent", function() {
			beforeEach(function() {
				this.DiffManager.getLatestDocAndUpdates = sinon.stub().callsArgWith(3, null, this.content, this.version, this.updates);
				this.DiffGenerator.buildDiff = sinon.stub().throws(this.error = new Error("inconsistent!"));
				return this.DiffManager.getDiff(this.project_id, this.doc_id, this.fromVersion, this.toVersion, this.callback);
			});

			return it("should call the callback with an error", function() {
				return this.callback
					.calledWith(this.error)
					.should.equal(true);
			});
		});
	});

	describe("getDocumentBeforeVersion", function() {
		beforeEach(function() {
			this.DiffManager._tryGetDocumentBeforeVersion = sinon.stub();
			this.document = "mock-documents";
			return this.rewound_updates = "mock-rewound-updates";
		});

		describe("succesfully", function() {
			beforeEach(function() {
				this.DiffManager._tryGetDocumentBeforeVersion.yields(null, this.document, this.rewound_updates);
				return this.DiffManager.getDocumentBeforeVersion(this.project_id, this.doc_id, this.version, this.callback);
			});
			
			it("should call _tryGetDocumentBeforeVersion", function() {
				return this.DiffManager._tryGetDocumentBeforeVersion
					.calledWith(this.project_id, this.doc_id, this.version)
					.should.equal(true);
			});
			
			return it("should call the callback with the response", function() {
				return this.callback.calledWith(null, this.document, this.rewound_updates).should.equal(true);
			});
		});
		
		describe("with a retry needed", function() {
			beforeEach(function() {
				let retried = false;
				this.DiffManager._tryGetDocumentBeforeVersion = (project_id, doc_id, version, callback) => {
					if (!retried) {
						retried = true;
						const error = new Error();
						error.retry = true;
						return callback(error);
					} else {
						return callback(null, this.document, this.rewound_updates);
					}
				};
				sinon.spy(this.DiffManager, "_tryGetDocumentBeforeVersion");
				return this.DiffManager.getDocumentBeforeVersion(this.project_id, this.doc_id, this.version, this.callback);
			});
			
			it("should call _tryGetDocumentBeforeVersion twice", function() {
				return this.DiffManager._tryGetDocumentBeforeVersion
					.calledTwice
					.should.equal(true);
			});
			
			return it("should call the callback with the response", function() {
				return this.callback.calledWith(null, this.document, this.rewound_updates).should.equal(true);
			});
		});
		
		describe("with a non-retriable error", function() {
			beforeEach(function() {
				this.error = new Error("oops");
				this.DiffManager._tryGetDocumentBeforeVersion.yields(this.error);
				return this.DiffManager.getDocumentBeforeVersion(this.project_id, this.doc_id, this.version, this.callback);
			});
			
			it("should call _tryGetDocumentBeforeVersion once", function() {
				return this.DiffManager._tryGetDocumentBeforeVersion
					.calledOnce
					.should.equal(true);
			});
			
			return it("should call the callback with the error", function() {
				return this.callback.calledWith(this.error).should.equal(true);
			});
		});
		
		return describe("when retry limit is matched", function() {
			beforeEach(function() {
				this.error = new Error("oops");
				this.error.retry = true;
				this.DiffManager._tryGetDocumentBeforeVersion.yields(this.error);
				return this.DiffManager.getDocumentBeforeVersion(this.project_id, this.doc_id, this.version, this.callback);
			});
			
			it("should call _tryGetDocumentBeforeVersion three times (max retries)", function() {
				return this.DiffManager._tryGetDocumentBeforeVersion
					.calledThrice
					.should.equal(true);
			});
			
			return it("should call the callback with the error", function() {
				return this.callback.calledWith(this.error).should.equal(true);
			});
		});
	});

	return describe("_tryGetDocumentBeforeVersion", function() {
		beforeEach(function() {
			this.content = "hello world";
			// Op versions are the version they were applied to, so doc is always one version
			// ahead.s
			this.version = 43;
			this.updates = [
				{ op: "mock-4", v: 42, meta: { start_ts: new Date(this.to.getTime() + 20)} },
				{ op: "mock-3", v: 41, meta: { start_ts: new Date(this.to.getTime() + 10)} },
				{ op: "mock-2", v: 40, meta: { start_ts: new Date(this.to.getTime() - 10)} },
				{ op: "mock-1", v: 39, meta: { start_ts: new Date(this.to.getTime() - 20)} }
			];
			this.fromVersion = 39;
			this.rewound_content = "rewound-content";
			return this.diff = [ {u: "mock-diff"} ];});
			
		describe("with matching versions", function() {
			beforeEach(function() {
				this.DiffManager.getLatestDocAndUpdates = sinon.stub().callsArgWith(3, null, this.content, this.version, this.updates);
				this.DiffGenerator.rewindUpdates = sinon.spy((content, updates) => {
					// the rewindUpdates method reverses the 'updates' array
					updates.reverse();
					return this.rewound_content;
				});
				this.rewindUpdatesWithArgs = this.DiffGenerator.rewindUpdates.withArgs(this.content, this.updates.slice().reverse());
				return this.DiffManager._tryGetDocumentBeforeVersion(this.project_id, this.doc_id, this.fromVersion, this.callback);
			});

			it("should get the latest doc and version with all recent updates", function() {
				return this.DiffManager.getLatestDocAndUpdates
					.calledWith(this.project_id, this.doc_id, this.fromVersion)
					.should.equal(true);
			});

			it("should rewind the diff", function() {
				return sinon.assert.calledOnce(this.rewindUpdatesWithArgs);
			});

			return it("should call the callback with the rewound document and updates", function() {
				return this.callback.calledWith(null, this.rewound_content, this.updates).should.equal(true);
			});
		});

		describe("with mismatching versions", function() {
			beforeEach(function() {
				this.version = 50;
				this.updates = [ { op: "mock-1", v: 40 }, { op: "mock-1", v: 39 } ];
				this.DiffManager.getLatestDocAndUpdates = sinon.stub().callsArgWith(3, null, this.content, this.version, this.updates);
				return this.DiffManager._tryGetDocumentBeforeVersion(this.project_id, this.doc_id, this.fromVersion, this.callback);
			});

			return it("should call the callback with an error with retry = true set", function() {
				this.callback.calledOnce.should.equal(true);
				const error = this.callback.args[0][0];
				return expect(error.retry).to.equal(true);
			});
		});

		return describe("when the updates are inconsistent", function() {
			beforeEach(function() {
				this.DiffManager.getLatestDocAndUpdates = sinon.stub().callsArgWith(3, null, this.content, this.version, this.updates);
				this.DiffGenerator.rewindUpdates = sinon.stub().throws(this.error = new Error("inconsistent!"));
				return this.DiffManager.getDocumentBeforeVersion(this.project_id, this.doc_id, this.fromVersion, this.callback);
			});

			return it("should call the callback with an error", function() {
				return this.callback
					.calledWith(this.error)
					.should.equal(true);
			});
		});
	});
});