import XCTest
import Foundation
import ForgeGrade
import ForgeColor
@testable import ForgeCamera

/// Recording driver: captures pushes, declares capabilities.
actor RecordingDriver: CameraDriver {
    nonisolated let capabilities: CameraCapabilities
    private(set) var pushedLooks = [FlattenedLook]()

    init(nativeCDL: Bool, lutSizes: [Int] = [17, 33]) {
        capabilities = CameraCapabilities(
            vendor: .simulated, supportsNativeCDL: nativeCDL,
            lut3dSizes: lutSizes, metadataFields: [])
    }

    nonisolated var state: AsyncStream<CameraState> {
        AsyncStream { _ in }
    }

    func connect() async throws {}
    func disconnect() async {}
    func push(look: FlattenedLook) async throws {
        pushedLooks.append(look)
    }
}

final class GangTests: XCTestCase {

    func makeGrade() -> GradeStack {
        GradeStack(nodes: [
            GradeNode(kind: .cdl(CDL(slope: SIMD3(1.2, 1, 0.9), offset: .zero, power: .one, saturation: 1.1))),
            GradeNode(kind: .saturation(0.95)),
        ])
    }

    // Push to ganged slots: each camera gets a look flattened per its own capabilities.
    func testGangPushRespectsCapabilities() async throws {
        let arriLike = RecordingDriver(nativeCDL: true)
        let sonyLike = RecordingDriver(nativeCDL: false)

        let gang = GradeGang(latticeSize: 17)
        await gang.setGrade(makeGrade(), for: "A")
        await gang.link(slots: ["A", "B"])
        await gang.register(slot: "A", driver: arriLike)
        await gang.register(slot: "B", driver: sonyLike)

        try await gang.pushGrade(from: "A")

        let arriPushes = await arriLike.pushedLooks
        let sonyPushes = await sonyLike.pushedLooks
        XCTAssertEqual(arriPushes.count, 1)
        XCTAssertEqual(sonyPushes.count, 1)
        // ARRI-like gets split CDL; Sony-like full bake, no CDL.
        XCTAssertNotNil(arriPushes[0].cdl)
        XCTAssertNil(sonyPushes[0].cdl)
        XCTAssertNotNil(sonyPushes[0].lut)
    }

    // Ganged edit propagates grade to linked slots.
    func testGangPropagatesGrade() async throws {
        let gang = GradeGang(latticeSize: 17)
        await gang.link(slots: ["A", "B", "C"])
        await gang.setGrade(makeGrade(), for: "A")

        let gradeB = await gang.grade(for: "B")
        let gradeC = await gang.grade(for: "C")
        XCTAssertEqual(gradeB?.nodes.count, 2)
        XCTAssertEqual(gradeC?.nodes.count, 2)
    }

    // Unlink stops propagation.
    func testUnlinkStopsPropagation() async throws {
        let gang = GradeGang(latticeSize: 17)
        await gang.link(slots: ["A", "B"])
        await gang.setGrade(makeGrade(), for: "A")
        await gang.unlink(slot: "B")

        // New grade on A only.
        let solo = GradeStack(nodes: [GradeNode(kind: .saturation(0.5))])
        await gang.setGrade(solo, for: "A")

        let gradeA = await gang.grade(for: "A")
        let gradeB = await gang.grade(for: "B")
        XCTAssertEqual(gradeA?.nodes.count, 1)
        XCTAssertEqual(gradeB?.nodes.count, 2) // stays on pre-unlink grade
    }

    // Per-slot override: editing an unlinked slot never touches others.
    func testSoloEditIsolated() async throws {
        let gang = GradeGang(latticeSize: 17)
        await gang.setGrade(makeGrade(), for: "A")
        await gang.setGrade(GradeStack(nodes: []), for: "B")

        let gradeA = await gang.grade(for: "A")
        let gradeB = await gang.grade(for: "B")
        XCTAssertEqual(gradeA?.nodes.count, 2)
        XCTAssertEqual(gradeB?.nodes.count, 0)
    }

    // Push from an unregistered slot throws.
    func testPushUnregisteredThrows() async {
        let gang = GradeGang(latticeSize: 17)
        await gang.setGrade(makeGrade(), for: "X")
        do {
            try await gang.pushGrade(from: "X")
            XCTFail("expected throw")
        } catch {}
    }

    // CDL-only camera (RED/RCP2, lut3dSizes empty): CDL-only grade pushes as bare CDL.
    func testCDLOnlyCameraPushesCDLOnlyGrade() async throws {
        let red = RecordingDriver(nativeCDL: true, lutSizes: [])
        let gang = GradeGang(latticeSize: 33)
        // Grade = single CDL node — representable on a CDL-only camera.
        let grade = GradeStack(nodes: [
            GradeNode(kind: .cdl(CDL(slope: SIMD3(1.3, 1, 1), offset: .zero, power: .one, saturation: 1.1))),
        ])
        await gang.setGrade(grade, for: "R")
        await gang.register(slot: "R", driver: red)
        try await gang.pushGrade(from: "R")

        let pushes = await red.pushedLooks
        XCTAssertEqual(pushes.count, 1)
        XCTAssertNotNil(pushes[0].cdl)
        XCTAssertNil(pushes[0].lut)
        XCTAssertEqual(pushes[0].cdl?.slope.x ?? 0, 1.3, accuracy: 1e-5)
    }

    // CDL-only camera + grade with non-CDL nodes: hard error (camera can't show it).
    func testCDLOnlyCameraRejectsComplexGrade() async throws {
        let red = RecordingDriver(nativeCDL: true, lutSizes: [])
        let gang = GradeGang(latticeSize: 33)
        await gang.setGrade(makeGrade(), for: "R") // CDL + saturation node
        await gang.register(slot: "R", driver: red)
        do {
            try await gang.pushGrade(from: "R")
            XCTFail("expected partial failure")
        } catch let e as GangError {
            guard case .partialFailure(let failures) = e else { return XCTFail("wrong error") }
            XCTAssertEqual(failures.count, 1)
        }
        let pushes = await red.pushedLooks
        XCTAssertTrue(pushes.isEmpty)
    }

    // Push failure on one camera doesn't block others (best-effort multi-push).
    func testPushPartialFailure() async throws {
        let good = RecordingDriver(nativeCDL: true)
        let bad = RecordingDriver(nativeCDL: false, lutSizes: [99]) // rejects 17

        let gang = GradeGang(latticeSize: 17)
        await gang.link(slots: ["A", "B"])
        await gang.setGrade(makeGrade(), for: "A")
        await gang.register(slot: "A", driver: good)
        await gang.register(slot: "B", driver: bad)

        // bad driver: flatten will target unsupported size -> per-slot error collected.
        do {
            try await gang.pushGrade(from: "A")
            XCTFail("expected partial failure to throw summary")
        } catch let e as GangError {
            guard case .partialFailure(let failures) = e else { return XCTFail("wrong error") }
            XCTAssertEqual(failures.count, 1)
            XCTAssertEqual(failures[0].slot, "B")
        }
        // Good camera still got its push.
        let pushes = await good.pushedLooks
        XCTAssertEqual(pushes.count, 1)
    }
}