import XCTest
@testable import TVAnarchyCore

final class TransferHealthTests: XCTestCase {
    func testStatusMapping() {
        func h(_ status: Int, complete: Bool = false, rate: Int = 0) -> TransferHealth {
            TransferHealth.classify(status: status, isComplete: complete, rateDownload: rate,
                                    peersConnected: 5, error: 0, secondsStuck: nil)
        }
        XCTAssertEqual(h(6), .seeding)
        XCTAssertEqual(h(0, complete: true), .done)
        XCTAssertEqual(h(0, complete: false), .stopped)
        XCTAssertEqual(h(1), .checking)
        XCTAssertEqual(h(3), .queued)
        XCTAssertEqual(h(4, rate: 1_000), .downloading)
    }

    func testErrorWins() {
        // Tracker error (2) and local error (3) are genuine → errored, beating an
        // otherwise-healthy downloading state.
        XCTAssertEqual(
            TransferHealth.classify(status: 4, isComplete: false, rateDownload: 5_000,
                                    peersConnected: 9, error: 3, secondsStuck: 0), .errored)
        XCTAssertEqual(
            TransferHealth.classify(status: 4, isComplete: false, rateDownload: 5_000,
                                    peersConnected: 9, error: 2, secondsStuck: 0), .errored)
    }

    /// A tracker *warning* (error == 1) is one tracker flapping on an otherwise
    /// healthy torrent — must NOT red-flag/notify (would spam on benign warnings).
    func testTrackerWarningIsNotErrored() {
        // Healthy downloading torrent that carries a stale tracker warning.
        XCTAssertEqual(
            TransferHealth.classify(status: 4, isComplete: false, rateDownload: 5_000,
                                    peersConnected: 9, error: 1, secondsStuck: 0), .downloading)
        // A seeding torrent with a tracker warning is still just seeding.
        XCTAssertEqual(
            TransferHealth.classify(status: 6, isComplete: true, rateDownload: 0,
                                    peersConnected: 0, error: 1, secondsStuck: nil), .seeding)
        XCTAssertFalse(TransferHealth.seeding.needsAttention)
    }

    func testStalledVsDeadThresholds() {
        // 0 rate, peers present, past the stall window → stalled.
        XCTAssertEqual(
            TransferHealth.classify(status: 4, isComplete: false, rateDownload: 0,
                                    peersConnected: 4, error: 0, secondsStuck: 130), .stalled)
        // 0 rate, NO peers, past the dead window → dead.
        XCTAssertEqual(
            TransferHealth.classify(status: 4, isComplete: false, rateDownload: 0,
                                    peersConnected: 0, error: 0, secondsStuck: 400), .dead)
        // briefly 0 rate, not yet past stall → still downloading (no false alarm).
        XCTAssertEqual(
            TransferHealth.classify(status: 4, isComplete: false, rateDownload: 0,
                                    peersConnected: 0, error: 0, secondsStuck: 10), .downloading)
    }

    func testAttentionAndSortOrder() {
        XCTAssertTrue(TransferHealth.errored.needsAttention)
        XCTAssertTrue(TransferHealth.dead.needsAttention)
        XCTAssertFalse(TransferHealth.downloading.needsAttention)
        // attention states sort ahead of active work, which sorts ahead of idle.
        XCTAssertLessThan(TransferHealth.dead.sortRank, TransferHealth.downloading.sortRank)
        XCTAssertLessThan(TransferHealth.downloading.sortRank, TransferHealth.seeding.sortRank)
    }

    @MainActor
    func testDownloadOrderAttentionFirstThenEta() {
        func row(_ id: Int, eta: Int) -> TorrentRow {
            try! JSONDecoder().decode(TorrentRow.self, from: Data(#"""
            {"id":\#(id),"name":"t\#(id)","percentDone":0.5,"status":4,"doneDate":0,"addedDate":1,
             "haveValid":1,"sizeWhenDone":2,"rateDownload":1,"rateUpload":0,"uploadRatio":0,
             "eta":\#(eta),"downloadDir":"/d"}
            """#.utf8))
        }
        let soon = row(1, eta: 60), later = row(2, eta: 600), dead = row(3, eta: -1)
        // dead needs attention → first regardless of ETA; then soonest ETA.
        XCTAssertTrue(DownloadsController.downloadOrder(dead, .dead, soon, .downloading))
        XCTAssertTrue(DownloadsController.downloadOrder(soon, .downloading, later, .downloading))
        XCTAssertFalse(DownloadsController.downloadOrder(later, .downloading, soon, .downloading))
    }

    /// A row from a pre-Part-E cli (no error/peers fields) still decodes + classifies.
    func testRowWithoutDebugFieldsDecodesAndClassifies() throws {
        let json = #"""
        {"id":1,"name":"X","percentDone":0.5,"status":4,"doneDate":0,"addedDate":1,
         "haveValid":1,"sizeWhenDone":2,"rateDownload":1000,"rateUpload":0,
         "uploadRatio":0,"eta":60,"downloadDir":"/d"}
        """#
        let row = try JSONDecoder().decode(TorrentRow.self, from: Data(json.utf8))
        XCTAssertNil(row.error)
        XCTAssertNil(row.peersConnected)
        XCTAssertEqual(row.health(), .downloading)
    }
}