//===----------------------------------------------------------------------===//
//
// This source file is part of the SwiftNIO open source project
//
// Copyright (c) 2017-2021 Apple Inc. and the SwiftNIO project authors
// Licensed under Apache License v2.0
//
// See LICENSE.txt for license information
// See CONTRIBUTORS.txt for the list of SwiftNIO project authors
//
// SPDX-License-Identifier: Apache-2.0
//
//===----------------------------------------------------------------------===//

import NIOCore
import NIOEmbedded
import NIOWebSocket
import XCTest

final class NIOWebSocketFrameAggregatorTests: XCTestCase {
    var channel: EmbeddedChannel!

    override func setUp() {
        channel = EmbeddedChannel(
            handler: NIOWebSocketFrameAggregator(
                minNonFinalFragmentSize: 1,
                maxAccumulatedFrameCount: 4,
                maxAccumulatedFrameSize: 32
            )
        )
    }

    override func tearDown() {
        XCTAssertEqual(try self.channel.finish().isClean, true)
    }

    func testEmptyButFinalFrameIsForwardedEvenIfMinNonFinalFragmentSizeIsGreaterThanZero() {
        let frame = WebSocketFrame(fin: true, opcode: .binary, data: ByteBuffer())
        XCTAssertNoThrow(try channel.writeInbound(frame))
        XCTAssertEqual(try channel.readInbound(as: WebSocketFrame.self), frame)
    }

    func testTooSmallAndNonFinalFrameThrows() {
        let frame = WebSocketFrame(fin: false, opcode: .binary, data: ByteBuffer())
        XCTAssertThrowsError(try channel.writeInbound(frame))
    }

    func testTooBigFrameThrows() {
        let frame = WebSocketFrame(fin: false, opcode: .binary, data: ByteBuffer(repeating: 2, count: 33))
        XCTAssertThrowsError(try channel.writeInbound(frame))
    }

    func testTooBigAccumulatedFrameThrows() {
        let frame1 = WebSocketFrame(fin: false, opcode: .binary, data: ByteBuffer(repeating: 2, count: 32))
        XCTAssertNoThrow(try channel.writeInbound(frame1))

        let frame2 = WebSocketFrame(fin: false, opcode: .binary, data: ByteBuffer(repeating: 3, count: 1))
        XCTAssertThrowsError(try channel.writeInbound(frame2))
    }

    func testTooManyFramesThrow() {
        let firstFrame = WebSocketFrame(fin: false, opcode: .binary, data: ByteBuffer(repeating: 2, count: 2))
        XCTAssertNoThrow(try channel.writeInbound(firstFrame))
        let fragment = WebSocketFrame(fin: false, opcode: .continuation, data: ByteBuffer(repeating: 2, count: 2))
        XCTAssertNoThrow(try channel.writeInbound(fragment))
        XCTAssertNoThrow(try channel.writeInbound(fragment))
        XCTAssertThrowsError(try channel.writeInbound(fragment))
    }
    func testAlmostTooManyFramesDoNotThrow() {
        let firstFrame = WebSocketFrame(fin: false, opcode: .binary, data: ByteBuffer(repeating: 2, count: 2))
        XCTAssertNoThrow(try channel.writeInbound(firstFrame))
        let fragment = WebSocketFrame(fin: false, opcode: .continuation, data: ByteBuffer(repeating: 2, count: 2))
        XCTAssertNoThrow(try channel.writeInbound(fragment))
        XCTAssertNoThrow(try channel.writeInbound(fragment))
        let lastFrame = WebSocketFrame(fin: true, opcode: .continuation, data: ByteBuffer(repeating: 2, count: 2))
        XCTAssertNoThrow(try channel.writeInbound(lastFrame))

        let completeFrame = WebSocketFrame(fin: true, opcode: .binary, data: ByteBuffer(repeating: 2, count: 8))

        XCTAssertEqual(try channel.readInbound(as: WebSocketFrame.self), completeFrame)
    }

    func testTextFrameIsStillATextFrameAfterAggregation() {
        let firstFrame = WebSocketFrame(fin: false, opcode: .text, data: ByteBuffer(repeating: 2, count: 2))
        XCTAssertNoThrow(try channel.writeInbound(firstFrame))
        let fragment = WebSocketFrame(fin: false, opcode: .continuation, data: ByteBuffer(repeating: 2, count: 2))
        XCTAssertNoThrow(try channel.writeInbound(fragment))
        XCTAssertNoThrow(try channel.writeInbound(fragment))
        let lastFrame = WebSocketFrame(fin: true, opcode: .continuation, data: ByteBuffer(repeating: 2, count: 2))
        XCTAssertNoThrow(try channel.writeInbound(lastFrame))

        let completeFrame = WebSocketFrame(fin: true, opcode: .text, data: ByteBuffer(repeating: 2, count: 8))
        XCTAssertEqual(try channel.readInbound(as: WebSocketFrame.self), completeFrame)
    }

    func testPingFrameIsForwarded() {
        let controlFrame = WebSocketFrame(fin: true, opcode: .ping, data: ByteBuffer())
        XCTAssertNoThrow(try channel.writeInbound(controlFrame))
        XCTAssertEqual(try channel.readInbound(as: WebSocketFrame.self), controlFrame)

        let fragment = WebSocketFrame(fin: false, opcode: .text, data: ByteBuffer(repeating: 2, count: 2))
        XCTAssertNoThrow(try channel.writeInbound(fragment))

        XCTAssertNoThrow(try channel.writeInbound(controlFrame))
        XCTAssertEqual(
            try channel.readInbound(as: WebSocketFrame.self),
            controlFrame,
            "should forward control frames during buffering"
        )
    }

    func testPongFrameIsForwarded() {
        let controlFrame = WebSocketFrame(fin: true, opcode: .pong, data: ByteBuffer())
        XCTAssertNoThrow(try channel.writeInbound(controlFrame))
        XCTAssertEqual(try channel.readInbound(as: WebSocketFrame.self), controlFrame)

        let fragment = WebSocketFrame(fin: false, opcode: .text, data: ByteBuffer(repeating: 2, count: 2))
        XCTAssertNoThrow(try channel.writeInbound(fragment))

        XCTAssertNoThrow(try channel.writeInbound(controlFrame))
        XCTAssertEqual(
            try channel.readInbound(as: WebSocketFrame.self),
            controlFrame,
            "should forward control frames during buffering"
        )
    }

    func testCloseConnectionFrameIsForwarded() {
        let controlFrame = WebSocketFrame(fin: true, opcode: .connectionClose, data: ByteBuffer())
        XCTAssertNoThrow(try channel.writeInbound(controlFrame))
        XCTAssertEqual(try channel.readInbound(as: WebSocketFrame.self), controlFrame)

        let fragment = WebSocketFrame(fin: false, opcode: .text, data: ByteBuffer(repeating: 2, count: 2))
        XCTAssertNoThrow(try channel.writeInbound(fragment))

        XCTAssertNoThrow(try channel.writeInbound(controlFrame))
        XCTAssertEqual(
            try channel.readInbound(as: WebSocketFrame.self),
            controlFrame,
            "should forward control frames during buffering"
        )
    }

    func testFrameAggregationWithMask() {
        var firstFrameData = ByteBuffer(repeating: 2, count: 2)
        let firsFrameMask: WebSocketMaskingKey = [1, 2, 3, 4]
        firstFrameData.webSocketMask(firsFrameMask)
        let firstFrame = WebSocketFrame(fin: false, opcode: .binary, maskKey: firsFrameMask, data: firstFrameData)
        XCTAssertNoThrow(try channel.writeInbound(firstFrame))

        var fragmentData = ByteBuffer(repeating: 3, count: 2)
        let fragmentMaskKey: WebSocketMaskingKey = [5, 6, 7, 8]
        fragmentData.webSocketMask(fragmentMaskKey)
        let fragment = WebSocketFrame(fin: false, opcode: .continuation, maskKey: fragmentMaskKey, data: fragmentData)
        XCTAssertNoThrow(try channel.writeInbound(fragment))
        XCTAssertNoThrow(try channel.writeInbound(fragment))

        var lastFrameData = ByteBuffer(repeating: 4, count: 2)
        let lastFrameMaskKey: WebSocketMaskingKey = [9, 10, 11, 12]
        lastFrameData.webSocketMask(lastFrameMaskKey)
        let lastFrame = WebSocketFrame(fin: true, opcode: .continuation, maskKey: lastFrameMaskKey, data: lastFrameData)
        XCTAssertNoThrow(try channel.writeInbound(lastFrame))

        let completeFrame = WebSocketFrame(
            fin: true,
            opcode: .binary,
            data: ByteBuffer(bytes: [2, 2, 3, 3, 3, 3, 4, 4])
        )
        XCTAssertEqual(try channel.readInbound(as: WebSocketFrame.self), completeFrame)
    }
}