import CoreMedia
import XCTest
@testable import DropTwoCore

final class CropEngineTests: XCTestCase {
    private var tempDirectory: URL!

    override func setUpWithError() throws {
        tempDirectory = FileManager.default.temporaryDirectory.appendingPathComponent(UUID().uuidString)
        try FileManager.default.createDirectory(at: tempDirectory, withIntermediateDirectories: true)
    }

    override func tearDownWithError() throws {
        try? FileManager.default.removeItem(at: tempDirectory)
    }

    // MARK: - Geometrie (rein arithmetisch, kein Video nötig)

    func testTargetSizeMatchesReadmeExamples() {
        XCTAssertEqual(
            CropEngine.targetSize(forSourceSize: CGSize(width: 1080, height: 1920)),
            CGSize(width: 1080, height: 1350)
        )
        XCTAssertEqual(
            CropEngine.targetSize(forSourceSize: CGSize(width: 2160, height: 3840)),
            CGSize(width: 2160, height: 2700)
        )
    }

    func testTargetSizeRoundsHeightToEvenNumber() {
        let size = CropEngine.targetSize(forSourceSize: CGSize(width: 217, height: 386))

        XCTAssertEqual(size.width, 217)
        XCTAssertEqual(size.height.truncatingRemainder(dividingBy: 2), 0)
    }

    // MARK: - End-to-End gegen einen synthetischen Clip

    func testCropsToTargetSizeAndKeepsAudioAndDuration() async throws {
        let clip = try TestVideoFactory.makeNineBySixteenClip(in: tempDirectory)
        let destination = tempDirectory.appendingPathComponent("out.mp4")

        try await CropEngine.crop(sourceURL: clip.url, destinationURL: destination)

        let resultInfo = try await VideoInspector.inspect(destination)
        let expectedSize = CropEngine.targetSize(forSourceSize: clip.size)
        XCTAssertEqual(resultInfo.pixelSize, expectedSize)
        XCTAssertEqual(resultInfo.codec, .h264)
        XCTAssertTrue(resultInfo.hasAudioTrack)
        XCTAssertEqual(CMTimeGetSeconds(resultInfo.duration), clip.seconds, accuracy: 0.3)
    }

    func testCropsWithoutAudioTrack() async throws {
        let clip = try TestVideoFactory.makeNineBySixteenClip(includeAudio: false, in: tempDirectory)
        let destination = tempDirectory.appendingPathComponent("out.mp4")

        try await CropEngine.crop(sourceURL: clip.url, destinationURL: destination)

        let resultInfo = try await VideoInspector.inspect(destination)
        XCTAssertFalse(resultInfo.hasAudioTrack)
    }

    func testReportsProgress() async throws {
        let clip = try TestVideoFactory.makeNineBySixteenClip(in: tempDirectory)
        let destination = tempDirectory.appendingPathComponent("out.mp4")

        var reportedValues: [Double] = []
        try await CropEngine.crop(sourceURL: clip.url, destinationURL: destination) { value in
            reportedValues.append(value)
        }

        XCTAssertFalse(reportedValues.isEmpty)
        XCTAssertEqual(reportedValues.last ?? 0, 1.0, accuracy: 0.15)
    }

    // MARK: - Ablehnungen

    func testRejectsNonNineBySixteenSource() async throws {
        let clip = try TestVideoFactory.makeClip(size: CGSize(width: 400, height: 400), in: tempDirectory)
        let destination = tempDirectory.appendingPathComponent("out.mp4")

        do {
            try await CropEngine.crop(sourceURL: clip.url, destinationURL: destination)
            XCTFail("Erwartete Ablehnung für eine Nicht-9:16-Quelle")
        } catch CropEngineError.sourceNotNineBySixteen {
            // erwartet
        }
    }

    func testRejectsExistingDestinationWithoutOverwrite() async throws {
        let clip = try TestVideoFactory.makeNineBySixteenClip(in: tempDirectory)
        let destination = tempDirectory.appendingPathComponent("out.mp4")
        FileManager.default.createFile(atPath: destination.path, contents: Data())

        do {
            try await CropEngine.crop(sourceURL: clip.url, destinationURL: destination)
            XCTFail("Erwartete Ablehnung wegen bestehender Zieldatei")
        } catch CropEngineError.destinationAlreadyExists {
            // erwartet
        }
    }

    func testOverwritesExistingDestinationWhenExplicitlyAllowed() async throws {
        let clip = try TestVideoFactory.makeNineBySixteenClip(in: tempDirectory)
        let destination = tempDirectory.appendingPathComponent("out.mp4")
        FileManager.default.createFile(atPath: destination.path, contents: Data("platzhalter".utf8))

        try await CropEngine.crop(
            sourceURL: clip.url,
            destinationURL: destination,
            options: .init(overwrite: true)
        )

        let resultInfo = try await VideoInspector.inspect(destination)
        XCTAssertEqual(resultInfo.pixelSize, CropEngine.targetSize(forSourceSize: clip.size))
    }

    func testRejectsUnsupportedContainer() async throws {
        let clip = try TestVideoFactory.makeNineBySixteenClip(in: tempDirectory)
        let destination = tempDirectory.appendingPathComponent("out.mxf")

        do {
            try await CropEngine.crop(sourceURL: clip.url, destinationURL: destination)
            XCTFail("Erwartete Ablehnung für ein MXF-Ziel")
        } catch CropEngineError.unsupportedContainer {
            // erwartet
        }
    }

    func testRejectsMovAsDestinationBecauseTargetIsFixedToMp4() async throws {
        let clip = try TestVideoFactory.makeNineBySixteenClip(in: tempDirectory)
        let destination = tempDirectory.appendingPathComponent("out.mov")

        do {
            try await CropEngine.crop(sourceURL: clip.url, destinationURL: destination)
            XCTFail("Erwartete Ablehnung für ein MOV-Ziel — Zielformat ist fest auf MP4 gesetzt")
        } catch CropEngineError.unsupportedContainer {
            // erwartet
        }
    }
}