//
//  QueueTests.swift
//  AudioStreamingTests
//
//  Created by Dimitrios Chatzieleftheriou on 04/06/2020.
//  Copyright © 2020 Decimal. All rights reserved.
//

import XCTest

@testable import AudioStreaming

class QueueTests: XCTestCase {
    func testQueue() {
        let queue = Queue<Int>()

        XCTAssertEqual(queue.count, 0)
        XCTAssertTrue(queue.isEmpty)

        for i in 10 ..< 30 {
            queue.enqueue(item: i)

            let all = Array(queue)
            let correct = Array((10 ... i).reversed())

            XCTAssertEqual(all, correct)
            XCTAssertEqual(queue.peek()!, 10)
            XCTAssertEqual(queue.count, i - 10 + 1)
        }

        for i in 10 ..< 30 {
            let all = Array(queue)
            let correct = Array((i ... 29).reversed())

            XCTAssertEqual(all, correct)
            XCTAssertEqual(queue.dequeue()!, i)
            XCTAssertEqual(queue.count, 30 - i - 1)
        }
    }

    func testAnElementCanSkipQueue() {
        let queue = Queue<Int>()

        queue.enqueue(item: 1)
        queue.enqueue(item: 2)
        queue.enqueue(item: 3)
        queue.enqueue(item: 4)

        XCTAssertEqual(queue.peek()!, 1)

        queue.skip(item: 5)

        XCTAssertEqual(queue.peek()!, 5)
    }

    func testManyElementsCanSkipQueue() {
        let queue = Queue<Int>()

        queue.enqueue(item: 1)
        queue.enqueue(item: 2)
        queue.enqueue(item: 3)

        XCTAssertEqual(queue.peek()!, 1)

        queue.skip(items: [4, 5, 6])

        XCTAssertEqual(queue.peek()!, 6)
    }

    func testDequeueingOrPeakItemOnAnEmptyQueueReturnsNil() {
        let queue = Queue<Int>()

        XCTAssertNil(queue.dequeue())
        XCTAssertNil(queue.peek())
    }

    func testRemovesAllElements() {
        let queue = Queue<Int>()
        for i in 0 ..< 10 {
            queue.enqueue(item: i)
        }

        queue.removeAll()
        XCTAssertTrue(queue.isEmpty)
    }

    func testInsertingAtSpecificIndex() {
           let queue = Queue<Int>()
           queue.enqueue(item: 1)
           queue.enqueue(item: 2)
           queue.enqueue(item: 3)

           queue.insert(item: 6, at: 1)

           XCTAssertEqual(queue.count, 4)
           XCTAssertEqual(queue.remove(at: 1), 6)
       }

       func testRemovingAtSpecificIndex() {
           let queue = Queue<Int>()
           queue.enqueue(item: 1)
           queue.enqueue(item: 2)
           queue.enqueue(item: 3)

           XCTAssertEqual(queue.remove(at: 1), 2)

           XCTAssertEqual(queue.count, 2)
       }
}