import CoreVideo
import Foundation
import Testing
@testable import Intercom

/// Real browser against the real server: headless Chrome opens the phone page, connects and decodes.
/// Opt-in: `MUSUBI_E2E=1 MUSUBI_E2E_INTERFACE=en0 swift test --filter BrowserEndToEnd`.
@Suite(.enabled(if: ProcessInfo.processInfo.environment["MUSUBI_E2E"] == "1"))
@MainActor struct BrowserEndToEndTests {
    static let chrome = "/Applications/Google Chrome.app/Contents/MacOS/Google Chrome"

    @Test(.timeLimit(.minutes(1))) func chromeReceivesTalkbackAndPreview() async throws {
        let interfaceName = ProcessInfo.processInfo.environment["MUSUBI_E2E_INTERFACE"] ?? "en0"
        let server = IntercomServer()
        await server.start(interfaceName: interfaceName)
        defer { server.stop() }
        let url = try #require(server.url, "Intercom did not start: \(server.error ?? "-")")

        let feeder = Feeder(input: server.input)
        feeder.start()
        defer { feeder.stop() }

        let profile = FileManager.default.temporaryDirectory.appendingPathComponent("musubi-chrome-\(UUID().uuidString)")
        let port = Int.random(in: 20_000...29_999)
        let chrome = Process()
        chrome.executableURL = URL(fileURLWithPath: Self.chrome)
        chrome.arguments = ["--headless=new", "--remote-debugging-port=\(port)", "--user-data-dir=\(profile.path)",
                            "--autoplay-policy=no-user-gesture-required", "--no-first-run", "--no-default-browser-check",
                            url.absoluteString]
        chrome.standardError = FileHandle.nullDevice
        try chrome.run()
        defer {
            chrome.terminate()
            try? FileManager.default.removeItem(at: profile)
        }

        let devtools = try await DevTools.connect(port: port)
        for _ in 0..<50 {
            if try await devtools.evaluate("!!document.querySelector('#join')") == "1" { break }
            try await Task.sleep(for: .milliseconds(200))
        }
        _ = try await devtools.evaluate("""
            document.querySelector('#name').value = 'Testgerät';
            document.querySelector('#role').value = 'Kamera 1';
            document.querySelector('#join').requestSubmit();
            true
            """)

        var last = ""
        for _ in 0..<40 {
            try await Task.sleep(for: .milliseconds(500))
            last = try await devtools.evaluate("""
                (async () => {
                  if (!pc) return 'none,0,0,' + location.href + ' ' + document.querySelector('#status')?.textContent;
                  let video = 0, audio = 0;
                  (await pc.getStats()).forEach(r => {
                    if (r.type === 'inbound-rtp' && r.kind === 'video') video = r.framesDecoded || 0;
                    if (r.type === 'inbound-rtp' && r.kind === 'audio') audio = r.packetsReceived || 0;
                  });
                  return pc.connectionState + ',' + video + ',' + audio + ',' + document.querySelector('#status').textContent;
                })()
                """)
            let parts = last.split(separator: ",")
            if parts.count >= 3, parts[0] == "connected", Int(parts[1]) ?? 0 >= 20, Int(parts[2]) ?? 0 >= 50 { break }
        }
        let delay = try await devtools.evaluate("""
            (async () => {
              let ms = -1;
              (await pc.getStats()).forEach(r => {
                if (r.type === 'inbound-rtp' && r.kind === 'video' && r.jitterBufferEmittedCount)
                  ms = Math.round(1000 * r.jitterBufferDelay / r.jitterBufferEmittedCount);
              });
              return ms;
            })()
            """)
        print("Browser: \(last) · video jitter buffer \(delay) ms")
        let parts = last.split(separator: ",").prefix(3)
        #expect(parts.first == "connected", "state: \(last)")
        #expect(Int(parts.dropFirst().first ?? "") ?? 0 >= 20, "video frames decoded: \(last)")
        #expect(Int(parts.last ?? "") ?? 0 >= 50, "audio packets received: \(last)")
        #expect(server.participants.first?.name == "Testgerät")
        #expect(server.participants.first?.connected == true)
    }
}

/// Pushes a moving test picture (25 fps) and a 440 Hz tone (20 ms blocks at 44.1 kHz to exercise resampling).
private final class Feeder: @unchecked Sendable {
    private let input: IntercomInput
    private let queue = DispatchQueue(label: "e2e.feeder")
    private var timer: DispatchSourceTimer?
    private var tick = 0
    private var phase = 0.0

    init(input: IntercomInput) { self.input = input }

    func start() {
        let timer = DispatchSource.makeTimerSource(queue: queue)
        timer.schedule(deadline: .now(), repeating: .milliseconds(20))
        timer.setEventHandler { [weak self] in self?.step() }
        timer.resume()
        self.timer = timer
    }

    func stop() { timer?.cancel() }

    private func step() {
        tick += 1
        var samples = [Float](repeating: 0, count: 882)
        for i in samples.indices {
            samples[i] = Float(sin(phase) * 0.2)
            phase += 2 * .pi * 440 / 44_100
        }
        samples.withUnsafeBufferPointer { input.pushTalkback($0, sampleRate: 44_100) }
        guard tick.isMultiple(of: 2) else { return }
        var buffer: CVPixelBuffer?
        CVPixelBufferCreate(nil, 1280, 720, kCVPixelFormatType_32BGRA, [kCVPixelBufferIOSurfacePropertiesKey: [:]] as CFDictionary, &buffer)
        guard let buffer else { return }
        CVPixelBufferLockBaseAddress(buffer, [])
        let base = CVPixelBufferGetBaseAddress(buffer)!.assumingMemoryBound(to: UInt8.self)
        let stride = CVPixelBufferGetBytesPerRow(buffer)
        for y in 0..<720 {
            for x in 0..<1280 {
                let p = base + y * stride + x * 4
                p[0] = UInt8((x + tick * 8) & 0xFF)
                p[1] = UInt8(y & 0xFF)
                p[2] = UInt8((tick * 4) & 0xFF)
                p[3] = 255
            }
        }
        CVPixelBufferUnlockBaseAddress(buffer, [])
        input.pushVideo(buffer)
    }
}

/// Just enough of the Chrome DevTools Protocol: Runtime.evaluate on the first page.
private final class DevTools: @unchecked Sendable {
    private let socket: URLSessionWebSocketTask
    private var nextID = 0

    private init(socket: URLSessionWebSocketTask) { self.socket = socket }

    static func connect(port: Int) async throws -> DevTools {
        struct Target: Decodable { let type: String; let webSocketDebuggerUrl: String? }
        for _ in 0..<50 {
            if let (data, _) = try? await URLSession.shared.data(from: URL(string: "http://127.0.0.1:\(port)/json")!),
               let targets = try? JSONDecoder().decode([Target].self, from: data),
               let page = targets.first(where: { $0.type == "page" }), let ws = page.webSocketDebuggerUrl {
                let socket = URLSession.shared.webSocketTask(with: URL(string: ws)!)
                socket.resume()
                return DevTools(socket: socket)
            }
            try await Task.sleep(for: .milliseconds(200))
        }
        throw URLError(.cannotConnectToHost)
    }

    func evaluate(_ expression: String) async throws -> String {
        nextID += 1
        let id = nextID
        let message: [String: Any] = ["id": id, "method": "Runtime.evaluate",
                                      "params": ["expression": expression, "awaitPromise": true, "returnByValue": true]]
        let data = try JSONSerialization.data(withJSONObject: message)
        try await socket.send(.string(String(decoding: data, as: UTF8.self)))
        while true {
            guard case .string(let text) = try await socket.receive(),
                  let json = try JSONSerialization.jsonObject(with: Data(text.utf8)) as? [String: Any],
                  json["id"] as? Int == id else { continue }
            let result = (json["result"] as? [String: Any])?["result"] as? [String: Any]
            return result?["value"].map { "\($0)" } ?? ""
        }
    }
}