var should = require('should'),
    sinon = require('sinon'),
    Promise = require('bluebird'),

    // Stuff we are testing
    pipeline = require('../../../../core/server/lib/promise/pipeline');

// These tests are based on the tests in https://github.com/cujojs/when/blob/3.7.4/test/pipeline-test.js
function createTask(y) {
    return function (x) {
        return x + y;
    };
}

describe('Pipeline', function () {
    afterEach(function () {
        sinon.restore();
    });

    it('should execute tasks in order', function () {
        return pipeline([createTask('b'), createTask('c'), createTask('d')], 'a').then(function (result) {
            result.should.eql('abcd');
        });
    });

    it('should resolve to initial args when no tasks supplied', function () {
        return pipeline([], 'a', 'b').then(function (result) {
            result.should.eql(['a', 'b']);
        });
    });

    it('should resolve to empty array when no tasks and no args supplied', function () {
        return pipeline([]).then(function (result) {
            result.should.eql([]);
        });
    });

    it('should pass args to initial task', function () {
        var expected = [1, 2, 3],
            tasks = [sinon.spy()];

        return pipeline(tasks, 1, 2, 3).then(function () {
            tasks[0].calledOnce.should.be.true();
            tasks[0].firstCall.args.should.eql(expected);
        });
    });

    it('should allow initial args to be promises', function () {
        var expected = [1, 2, 3],
            tasks = [sinon.spy()],
            Resolver = Promise.resolve;

        return pipeline(tasks, new Resolver(1), new Resolver(2), new Resolver(3)).then(function () {
            tasks[0].calledOnce.should.be.true();
            tasks[0].firstCall.args.should.eql(expected);
        });
    });

    it('should allow tasks to be promises', function () {
        var expected = [1, 2, 3],
            tasks = [
                sinon.stub().returns(new Promise.resolve(4)),
                sinon.stub().returns(new Promise.resolve(5)),
                sinon.stub().returns(new Promise.resolve(6))
            ];

        return pipeline(tasks, 1, 2, 3).then(function (result) {
            result.should.eql(6);
            tasks[0].calledOnce.should.be.true();
            tasks[0].firstCall.args.should.eql(expected);
            tasks[1].calledOnce.should.be.true();
            tasks[1].firstCall.calledWith(4).should.be.true();
            tasks[2].calledOnce.should.be.true();
            tasks[2].firstCall.calledWith(5).should.be.true();
        });
    });

    it('should allow tasks and args to be promises', function () {
        var expected = [1, 2, 3],
            tasks = [
                sinon.stub().returns(new Promise.resolve(4)),
                sinon.stub().returns(new Promise.resolve(5)),
                sinon.stub().returns(new Promise.resolve(6))
            ],
            Resolver = Promise.resolve;

        return pipeline(tasks, new Resolver(1), new Resolver(2), new Resolver(3)).then(function (result) {
            result.should.eql(6);
            tasks[0].calledOnce.should.be.true();
            tasks[0].firstCall.args.should.eql(expected);
            tasks[1].calledOnce.should.be.true();
            tasks[1].firstCall.calledWith(4).should.be.true();
            tasks[2].calledOnce.should.be.true();
            tasks[2].firstCall.calledWith(5).should.be.true();
        });
    });
});
