import XCTest

/// Playing an episode has to leave the page, reach the host's player, and be written back.
///
/// Point it at the daemon the browser suite uses, which has fixture feeds and real files:
///
///   node -e "require('./tests/ui/global-setup').prepare()"   # in ipodderx-rs
///   node tests/ui/fixtures/serve.js &
///   IPX_CONFIG=$ROOT/config/config.toml IPX_DATA_DIR=$ROOT/data ./target/debug/ipx daemon &
///   TEST_RUNNER_IPX_SERVER="http://127.0.0.1:8791/?token=<the fixture token>" xcodebuild test ...
///
/// TEST_RUNNER_ is not decoration: the test runs in its own process on the simulator, and that
/// prefix is what carries a variable across to it.
final class PlaybackTests: XCTestCase {
    /// Not "First Episode". The fixture caps downloads at one per scan and takes the newest, so
    /// the second is the one with a file behind it -- and an episode with nothing downloaded
    /// offers Download rather than Play.
    let feed = "test-show", guid = "ui-2", title = "Second Episode"

    func testPlayingAnEpisodeReachesTheHostAndComesBack() throws {
        let server = ProcessInfo.processInfo.environment["IPX_SERVER"] ?? ""
        try XCTSkipIf(server.isEmpty, "set TEST_RUNNER_IPX_SERVER to a daemon with an episode downloaded")
        let base = try XCTUnwrap(URL(string: server))

        // Unread first, so that becoming read again can only be playback's doing. Set through
        // the API rather than by driving the interface: what is being tested is the playing.
        try setRead(false, in: base)

        let app = XCUIApplication()
        app.launchArguments = ["-ipx.server", server]
        app.launch()

        let episode = app.staticTexts[title]
        XCTAssertTrue(episode.waitForExistence(timeout: 30), "the list never showed the fixture episode")

        // The row's own play button. Every row with a downloaded file has one.
        let play = app.buttons["Play"].firstMatch
        XCTAssertTrue(play.waitForExistence(timeout: 15),
                      "no row offers to play, so nothing in the list has a downloaded file")
        play.tap()

        // Read again, rather than a position: the browser suite's fixture is a sixth of a second
        // long and a position that rounds to zero is never written. Read is set at the end of an
        // episode, by the host, which is the whole round trip.
        XCTAssertTrue(waitForRead(in: base, timeout: 30),
                      "the episode never came back read, so the host never played it through")
    }

    /// Sets read through ipx directly, to put the fixture in a known state first.
    private func setRead(_ read: Bool, in server: URL) throws {
        var components = try XCTUnwrap(URLComponents(url: server, resolvingAgainstBaseURL: false))
        components.path = "/api/entries/\(feed)/\(guid)/flags"
        var req = URLRequest(url: try XCTUnwrap(components.url))
        req.httpMethod = "POST"
        req.setValue("application/json", forHTTPHeaderField: "Content-Type")
        req.httpBody = try JSONSerialization.data(withJSONObject: ["read": read])
        let done = expectation(description: "flags written")
        URLSession.shared.dataTask(with: req) { _, _, _ in done.fulfill() }.resume()
        wait(for: [done], timeout: 15)
    }

    private func entry(in server: URL) -> [String: Any]? {
        var components = URLComponents(url: server, resolvingAgainstBaseURL: false)!
        components.path = "/api/entries"
        guard let url = components.url, let data = try? Data(contentsOf: url),
              let page = try? JSONSerialization.jsonObject(with: data) as? [String: Any],
              let entries = page["entries"] as? [[String: Any]] else { return nil }
        return entries.first { $0["guid"] as? String == guid }
    }

    /// Polls until the server says the episode is read. Its own request, not the app's -- the
    /// point is to ask the server what it ended up with.
    private func waitForRead(in server: URL, timeout: TimeInterval) -> Bool {
        let deadline = Date().addingTimeInterval(timeout)
        while Date() < deadline {
            if entry(in: server)?["read"] as? Bool == true { return true }
            Thread.sleep(forTimeInterval: 1)
        }
        return false
    }
}