var async = require('../lib');
var {expect} = require('chai');
var assert = require('assert');


describe('queue', function(){
    // several tests of these tests are flakey with timing issues
    this.retries(3);

    it('basics', (done) => {

        var call_order = [];
        var delays = [50,10,180,10];

        // worker1: --1-4
        // worker2: -2---3
        // order of completion: 2,1,4,3

        var q = async.queue((task, callback) => {
            setTimeout(() => {
                call_order.push('process ' + task);
                callback('error', 'arg');
            }, delays.shift());
        }, 2);

        q.push(1, (err, arg) => {
            expect(err).to.equal('error');
            expect(arg).to.equal('arg');
            expect(q.length()).to.equal(1);
            call_order.push('callback ' + 1);
        });
        q.push(2, (err, arg) => {
            expect(err).to.equal('error');
            expect(arg).to.equal('arg');
            expect(q.length()).to.equal(2);
            call_order.push('callback ' + 2);
        });
        q.push(3, (err, arg) => {
            expect(err).to.equal('error');
            expect(arg).to.equal('arg');
            expect(q.length()).to.equal(0);
            call_order.push('callback ' + 3);
        });
        q.push(4, (err, arg) => {
            expect(err).to.equal('error');
            expect(arg).to.equal('arg');
            expect(q.length()).to.equal(0);
            call_order.push('callback ' + 4);
        });
        expect(q.length()).to.equal(4);
        expect(q.concurrency).to.equal(2);

        q.drain(() => {
            expect(call_order).to.eql([
                'process 2', 'callback 2',
                'process 1', 'callback 1',
                'process 4', 'callback 4',
                'process 3', 'callback 3'
            ]);
            expect(q.concurrency).to.equal(2);
            expect(q.length()).to.equal(0);
            done();
        });
    });

    it('default concurrency', (done) => {
        var call_order = [],
            delays = [50,10,180,10];

        // order of completion: 1,2,3,4

        var q = async.queue((task, callback) => {
            setTimeout(() => {
                call_order.push('process ' + task);
                callback('error', 'arg');
            }, delays.shift());
        });

        q.push(1, (err, arg) => {
            expect(err).to.equal('error');
            expect(arg).to.equal('arg');
            expect(q.length()).to.equal(3);
            call_order.push('callback ' + 1);
        });
        q.push(2, (err, arg) => {
            expect(err).to.equal('error');
            expect(arg).to.equal('arg');
            expect(q.length()).to.equal(2);
            call_order.push('callback ' + 2);
        });
        q.push(3, (err, arg) => {
            expect(err).to.equal('error');
            expect(arg).to.equal('arg');
            expect(q.length()).to.equal(1);
            call_order.push('callback ' + 3);
        });
        q.push(4, (err, arg) => {
            expect(err).to.equal('error');
            expect(arg).to.equal('arg');
            expect(q.length()).to.equal(0);
            call_order.push('callback ' + 4);
        });
        expect(q.length()).to.equal(4);
        expect(q.concurrency).to.equal(1);

        q.drain(() => {
            expect(call_order).to.eql([
                'process 1', 'callback 1',
                'process 2', 'callback 2',
                'process 3', 'callback 3',
                'process 4', 'callback 4'
            ]);
            expect(q.concurrency).to.equal(1);
            expect(q.length()).to.equal(0);
            done();
        });
    });

    it('zero concurrency', (done) => {
        expect(() => {
            async.queue((task, callback) => {
                callback(null, task);
            }, 0);
        }).to.throw();
        done();
    });

    it('error propagation', (done) => {
        var results = [];

        var q = async.queue((task, callback) => {
            callback(task.name === 'foo' ? new Error('fooError') : null);
        }, 2);

        q.drain(() => {
            expect(results).to.eql(['bar', 'fooError']);
            done();
        });

        q.push({name: 'bar'}, (err) => {
            if(err) {
                results.push('barError');
                return;
            }

            results.push('bar');
        });

        q.push({name: 'foo'}, (err) => {
            if(err) {
                results.push('fooError');
                return;
            }

            results.push('foo');
        });
    });

    it('pushAsync', done => {
        const calls = []
        var q = async.queue((task, cb) => {
            if (task === 2) return cb(new Error('fail'))
            cb()
        })

        q.pushAsync(1, () => { throw new Error('should not be called') }).then(() => calls.push(1))
        q.pushAsync(2).catch(err => {
            expect(err.message).to.equal('fail')
            calls.push(2)
        })
        q.pushAsync([3, 4]).map(p => p.then(() => calls.push('arr')))
        q.drain(() => setTimeout(() => {
            expect(calls).to.eql([1, 2, 'arr', 'arr'])
            done()
        }))
    })

    it('unshiftAsync', done => {
        const calls = []
        var q = async.queue((task, cb) => {
            if (task === 2) return cb(new Error('fail'))
            cb()
        })

        q.unshiftAsync(1).then(() => calls.push(1))
        q.unshiftAsync(2).catch(err => {
            expect(err.message).to.equal('fail')
            calls.push(2)
        })
        q.unshiftAsync([3, 4]).map(p => p.then(() => calls.push('arr')))
        q.drain(() => setTimeout(() => {
            expect(calls).to.eql(['arr', 'arr', 2, 1])
            done()
        }))
    })

    it('global error handler', (done) => {
        var results = [];

        var q = async.queue((task, callback) => {
            callback(task.name === 'foo' ? new Error('fooError') : null);
        }, 2);

        q.error((error, task) => {
            expect(error).to.exist;
            expect(error.message).to.equal('fooError');
            expect(task.name).to.equal('foo');
            results.push('fooError');
        });

        q.drain (() => {
            expect(results).to.eql(['fooError', 'bar']);
            done();
        });

        q.push({name: 'foo'});

        q.push({name: 'bar'}, (error) => {
            expect(error).to.not.exist;
            results.push('bar');
        });
    });

    // The original queue implementation allowed the concurrency to be changed only
    // on the same event loop during which a task was added to the queue. This
    // test attempts to be a more robust test.
    // Start with a concurrency of 1. Wait until a leter event loop and change
    // the concurrency to 2. Wait again for a later loop then verify the concurrency
    // Repeat that one more time by chaning the concurrency to 5.
    it('changing concurrency', (done) => {

        var q = async.queue((task, callback) => {
            setTimeout(() => {
                callback();
            }, 10);
        }, 1);

        for(var i = 0; i < 50; i++){
            q.push('');
        }

        q.drain(done);

        setTimeout(() => {
            expect(q.concurrency).to.equal(1);
            q.concurrency = 2;
            setTimeout(() => {
                expect(q.running()).to.equal(2);
                q.concurrency = 5;
                setTimeout(() => {
                    expect(q.running()).to.equal(5);
                }, 40);
            }, 40);
        }, 40);
    });

    it('push without callback', function(done) {
        this.retries(3); // test can be flakey

        var call_order = [];
        var delays = [50,10,180,10];
        var concurrencyList = [];
        var running = 0;

        // worker1: --1-4
        // worker2: -2---3
        // order of completion: 2,1,4,3

        var q = async.queue((task, callback) => {
            running++;
            concurrencyList.push(running);
            setTimeout(() => {
                call_order.push('process ' + task);
                running--;
                callback('error', 'arg');
            }, delays.shift());
        }, 2);

        q.push(1);
        q.push(2);
        q.push(3);
        q.push(4);

        q.drain(() => {
            expect(running).to.eql(0);
            expect(concurrencyList).to.eql([1, 2, 2, 2]);
            expect(call_order).to.eql([
                'process 2',
                'process 1',
                'process 4',
                'process 3'
            ]);
            done();
        });
    });

    it('push with non-function', (done) => {
        var q = async.queue(() => {}, 1);
        expect(() => {
            q.push({}, 1);
        }).to.throw();
        done();
    });

    it('push with arrays', (done) => {
        const tasks = []
        var q = async.queue((task, cb) => {
            tasks.push(task)
            cb()
        }, 1);

        q.push([[1, 2, 3], [4, 5, 6]])

        q.drain(() => {
            expect(tasks).to.eql([
                [1, 2, 3],
                [4, 5, 6]
            ])
            done()
        })
    })

    it('unshift', (done) => {
        var queue_order = [];

        var q = async.queue((task, callback) => {
            queue_order.push(task);
            callback();
        }, 1);

        q.unshift(4);
        q.unshift(3);
        q.unshift(2);
        q.unshift(1);

        setTimeout(() => {
            expect(queue_order).to.eql([ 1, 2, 3, 4 ]);
            done();
        }, 100);
    });

    it('too many callbacks', (done) => {
        var q = async.queue((task, callback) => {
            callback();
            expect(() => {
                callback();
            }).to.throw();
            done();
        }, 2);

        q.push(1);
    });

    it('bulk task', (done) => {
        var call_order = [],
            delays = [50,10,180,10];

        // worker1: --1-4
        // worker2: -2---3
        // order of completion: 2,1,4,3

        var q = async.queue((task, callback) => {
            setTimeout(() => {
                call_order.push('process ' + task);
                callback('error', task);
            }, delays.splice(0,1)[0]);
        }, 2);

        q.push( [1,2,3,4], (err, arg) => {
            expect(err).to.equal('error');
            call_order.push('callback ' + arg);
        });

        expect(q.length()).to.equal(4);
        expect(q.concurrency).to.equal(2);

        q.drain(() => {
            expect(call_order).to.eql([
                'process 2', 'callback 2',
                'process 1', 'callback 1',
                'process 4', 'callback 4',
                'process 3', 'callback 3'
            ]);
            expect(q.concurrency).to.equal(2);
            expect(q.length()).to.equal(0);
            done();
        });
    });

    it('idle', (done) => {
        var q = async.queue((task, callback) => {
            // Queue is busy when workers are running
            expect(q.idle()).to.equal(false);
            callback();
        }, 1);

        // Queue is idle before anything added
        expect(q.idle()).to.equal(true);

        q.unshift(4);
        q.unshift(3);
        q.unshift(2);
        q.unshift(1);

        // Queue is busy when tasks added
        expect(q.idle()).to.equal(false);

        q.drain(() => {
            // Queue is idle after drain
            expect(q.idle()).to.equal(true);
            done();
        });
    });

    it('pause', (done) => {
        var call_order = [];
        var running = 0;
        var concurrencyList = [];
        var pauseCalls = ['process 1', 'process 2', 'process 3'];

        var q = async.queue((task, callback) => {
            running++;
            call_order.push('process ' + task);
            concurrencyList.push(running);
            setTimeout(() => {
                running--;
                callback();
            }, 10)
        }, 2);

        q.push(1);
        q.push(2, after2);
        q.push(3);

        function after2() {
            q.pause();
            expect(concurrencyList).to.eql([1, 2, 2]);
            expect(call_order).to.eql(pauseCalls);

            setTimeout(whilePaused, 5);
            setTimeout(afterPause, 10);
        }

        function whilePaused() {
            q.push(4);
        }

        function afterPause() {
            expect(concurrencyList).to.eql([1, 2, 2]);
            expect(call_order).to.eql(pauseCalls);
            q.resume();
            q.push(5);
            q.push(6);
            q.drain(drain);
        }
        function drain () {
            expect(concurrencyList).to.eql([1, 2, 2, 1, 2, 2]);
            expect(call_order).to.eql([
                'process 1',
                'process 2',
                'process 3',
                'process 4',
                'process 5',
                'process 6'
            ]);
            done();
        }
    });

    it('pause in worker with concurrency', (done) => {
        var call_order = [];
        var q = async.queue((task, callback) => {
            if (task.isLongRunning) {
                q.pause();
                setTimeout(() => {
                    call_order.push(task.id);
                    q.resume();
                    callback();
                }, 50);
            }
            else {
                call_order.push(task.id);
                setTimeout(callback, 10);
            }
        }, 10);

        q.push({ id: 1, isLongRunning: true});
        q.push({ id: 2 });
        q.push({ id: 3 });
        q.push({ id: 4 });
        q.push({ id: 5 });

        q.drain(() => {
            expect(call_order).to.eql([1, 2, 3, 4, 5]);
            done();
        });
    });

    it('start paused', (done) => {
        var q = async.queue((task, callback) => {
            if (task === 2) {
                expect(q.length()).to.equal(1);
                expect(q.running()).to.equal(2);
            }

            setTimeout(() => {
                callback();
            }, 40);
        }, 2);
        q.pause();

        q.push([1, 2, 3]);

        setTimeout(() => {
            expect(q.running()).to.equal(0);
            q.resume();
        }, 5);

        q.drain(done);
    });

    it('kill', (done) => {
        var q = async.queue((/*task, callback*/) => {
            setTimeout(() => {
                throw new Error("Function should never be called");
            }, 20);
        }, 1);
        q.drain(() => {
            throw new Error("Function should never be called");
        });

        q.push(0);

        q.kill();

        setTimeout(() => {
            expect(q.length()).to.equal(0);
            done();
        }, 40);
    });

    it('events', (done) => {
        var calls = [];
        var q = async.queue((task, cb) => {
            // nop
            calls.push('process ' + task);
            setTimeout(cb, 10);
        }, 3);
        q.concurrency = 3;

        q.saturated(() => {
            assert(q.running() == 3, 'queue should be saturated now');
            calls.push('saturated');
        });
        q.empty(() => {
            assert(q.length() === 0, 'queue should be empty now');
            calls.push('empty');
        });
        q.drain(() => {
            assert(
                q.length() === 0 && q.running() === 0,
                'queue should be empty now and no more workers should be running'
            );
            calls.push('drain');
            expect(calls).to.eql([
                'process foo',
                'process bar',
                'saturated',
                'process zoo',
                'foo cb',
                'saturated',
                'process poo',
                'bar cb',
                'empty',
                'saturated',
                'process moo',
                'zoo cb',
                'poo cb',
                'moo cb',
                'drain'
            ]);
            done();
        });
        q.push('foo', () => {calls.push('foo cb');});
        q.push('bar', () => {calls.push('bar cb');});
        q.push('zoo', () => {calls.push('zoo cb');});
        q.push('poo', () => {calls.push('poo cb');});
        q.push('moo', () => {calls.push('moo cb');});
    });

    it('empty', (done) => {
        var calls = [];
        var q = async.queue((task, cb) => {
            // nop
            calls.push('process ' + task);
            async.setImmediate(cb);
        }, 3);

        q.drain(() => {
            assert(
                q.length() === 0 && q.running() === 0,
                'queue should be empty now and no more workers should be running'
            );
            calls.push('drain');
            expect(calls).to.eql([
                'drain'
            ]);
            done();
        });
        q.push([]);
    });


    // #1367
    it('empty and not idle()', (done) => {
        var calls = [];
        var q = async.queue((task, cb) => {
            // nop
            calls.push('process ' + task);
            async.setImmediate(cb);
        }, 1);

        q.empty(() => {
            calls.push('empty');
            assert(q.idle() === false,
                'tasks should be running when empty is called')
            expect(q.running()).to.equal(1);
        })

        q.drain(() => {
            calls.push('drain');
            expect(calls).to.eql([
                'empty',
                'process 1',
                'drain'
            ]);
            done();
        });
        q.push(1);
    });

    it('saturated', (done) => {
        var saturatedCalled = false;
        var q = async.queue((task, cb) => {
            async.setImmediate(cb);
        }, 2);

        q.saturated(() => {
            saturatedCalled = true;
        })
        q.drain(() => {
            assert(saturatedCalled, "saturated not called");
            done();
        })

        q.push(['foo', 'bar', 'baz', 'moo']);
    });

    it('started', (done) => {

        var q = async.queue((task, cb) => {
            cb(null, task);
        });

        expect(q.started).to.equal(false);
        q.push('a');
        expect(q.started).to.equal(true);
        done();
    });

    context('q.saturated(): ', () => {
        it('should call the saturated callback if tasks length is concurrency', (done) => {
            var calls = [];
            var q = async.queue((task, cb) => {
                calls.push('process ' + task);
                async.setImmediate(cb);
            }, 4);
            q.saturated(() => {
                calls.push('saturated');
            });
            q.empty(() => {
                expect(calls.indexOf('saturated')).to.be.above(-1);
                setTimeout(() => {
                    expect(calls).eql([
                        'process foo0',
                        'process foo1',
                        'process foo2',
                        "saturated",
                        'process foo3',
                        'foo0 cb',
                        "saturated",
                        'process foo4',
                        'foo1 cb',
                        'foo2 cb',
                        'foo3 cb',
                        'foo4 cb'
                    ]);
                    done();
                }, 50);
            });
            q.push('foo0', () => {calls.push('foo0 cb');});
            q.push('foo1', () => {calls.push('foo1 cb');});
            q.push('foo2', () => {calls.push('foo2 cb');});
            q.push('foo3', () => {calls.push('foo3 cb');});
            q.push('foo4', () => {calls.push('foo4 cb');});
        });
    });

    context('q.unsaturated(): ', () => {
        it('should have a default buffer property that equals 25% of the concurrenct rate', (done) => {
            var calls = [];
            var q = async.queue((task, cb) => {
                // nop
                calls.push('process ' + task);
                async.setImmediate(cb);
            }, 10);
            expect(q.buffer).to.equal(2.5);
            done();
        });
        it('should allow a user to change the buffer property', (done) => {
            var calls = [];
            var q = async.queue((task, cb) => {
                // nop
                calls.push('process ' + task);
                async.setImmediate(cb);
            }, 10);
            q.buffer = 4;
            expect(q.buffer).to.not.equal(2.5);
            expect(q.buffer).to.equal(4);
            done();
        });
        it('should call the unsaturated callback if tasks length is less than concurrency minus buffer', (done) => {
            var calls = [];
            var q = async.queue((task, cb) => {
                calls.push('process ' + task);
                async.setImmediate(cb);
            }, 4);
            q.unsaturated(() => {
                calls.push('unsaturated');
            });
            q.empty(() => {
                expect(calls.indexOf('unsaturated')).to.be.above(-1);
                setTimeout(() => {
                    expect(calls).eql([
                        'process foo0',
                        'process foo1',
                        'process foo2',
                        'process foo3',
                        'foo0 cb',
                        'unsaturated',
                        'process foo4',
                        'foo1 cb',
                        'unsaturated',
                        'foo2 cb',
                        'unsaturated',
                        'foo3 cb',
                        'unsaturated',
                        'foo4 cb',
                        'unsaturated'
                    ]);
                    done();
                }, 50);
            });
            q.push('foo0', () => {calls.push('foo0 cb');});
            q.push('foo1', () => {calls.push('foo1 cb');});
            q.push('foo2', () => {calls.push('foo2 cb');});
            q.push('foo3', () => {calls.push('foo3 cb');});
            q.push('foo4', () => {calls.push('foo4 cb');});
        });
    });

    context('workersList', () => {
        it('should be the same length as running()', (done) => {
            var q = async.queue((task, cb) => {
                async.setImmediate(() => {
                    expect(q.workersList().length).to.equal(q.running());
                    cb();
                });
            }, 2);

            q.drain(() => {
                expect(q.workersList().length).to.equal(0);
                expect(q.running()).to.equal(0);
                done();
            });

            q.push('foo');
            q.push('bar');
            q.push('baz');
        });

        it('should contain the items being processed', (done) => {
            var itemsBeingProcessed = {
                'foo': ['foo'],
                'foo_cb': ['foo', 'bar'],
                'bar': ['foo', 'bar'],
                'bar_cb': ['bar', 'baz'],
                'baz': ['bar', 'baz'],
                'baz_cb': ['baz']
            };

            function getWorkersListData(q) {
                return q.workersList().map((v) => {
                    return v.data;
                });
            }

            var q = async.queue((task, cb) => {
                expect(
                    getWorkersListData(q)
                ).to.eql(itemsBeingProcessed[task]);
                expect(q.workersList().length).to.equal(q.running());
                async.setImmediate(() => {
                    expect(
                        getWorkersListData(q)
                    ).to.eql(itemsBeingProcessed[task+'_cb']);
                    expect(q.workersList().length).to.equal(q.running());
                    cb();
                });
            }, 2);

            q.drain(() => {
                expect(q.workersList()).to.eql([]);
                expect(q.workersList().length).to.equal(q.running());
                done();
            });

            q.push('foo');
            q.push('bar');
            q.push('baz');
        });
    })

    it('remove', (done) => {
        var result = [];
        var q = async.queue((data, cb) => {
            result.push(data);
            async.setImmediate(cb);
        });

        q.push([1, 2, 3, 4, 5]);

        q.remove((node) => {
            return node.data === 3;
        });

        q.drain(() => {
            expect(result).to.eql([1, 2, 4, 5]);
            done();
        })
    });

    it('should be iterable', (done) => {
        var q = async.queue((data, cb) => {
            if (data === 3) {
                q.push(6)
                expect([...q]).to.eql([4, 5, 6]);
            }
            async.setImmediate(cb);
        });

        q.push([1, 2, 3, 4, 5]);

        expect([...q]).to.eql([1, 2, 3, 4, 5]);

        q.drain(() => {
            expect([...q]).to.eql([]);
            done();
        })
    })

    it('should error when re-assigning event methods', () => {
        var q = async.queue(() => {})
        expect(() => {
            q.drain = () => {}
        }).to.throw()
    })
});