import Foundation
import XCTest
@testable import VelodyDomain

final class OfflineLibrarySearchTests: XCTestCase {
    func testSearchByTitleFiltersMatchingTracks() {
        let snapshot = makeSnapshot()

        let filtered = snapshot.filtered(searchText: "trap")

        XCTAssertEqual(filtered.remoteTracks.map(\.remoteTrack.trackId), ["remote-light-trap"])
        XCTAssertEqual(filtered.availableTracks.map(\.remoteTrackId), ["remote-light-trap"])
    }

    func testSearchByArtistFiltersMatchingTracks() {
        let snapshot = makeSnapshot()

        let filtered = snapshot.filtered(searchText: "unknown")

        XCTAssertEqual(filtered.remoteTracks.map(\.remoteTrack.trackId), ["remote-light-trap"])
        XCTAssertEqual(filtered.availableTracks.map(\.remoteTrackId), ["remote-light-trap"])
    }

    func testSearchIsCaseInsensitiveAndTrimsWhitespace() {
        let snapshot = makeSnapshot()

        let filtered = snapshot.filtered(searchText: "  TRAP  ")

        XCTAssertEqual(filtered.remoteTracks.map(\.remoteTrack.trackId), ["remote-light-trap"])
        XCTAssertEqual(filtered.availableTracks.map(\.remoteTrackId), ["remote-light-trap"])
    }

    func testEmptySearchResultReturnsEmptySections() {
        let snapshot = makeSnapshot()

        let filtered = snapshot.filtered(searchText: "nope")

        XCTAssertTrue(filtered.remoteTracks.isEmpty)
        XCTAssertTrue(filtered.availableTracks.isEmpty)
    }

    func testClearingSearchRestoresFullList() {
        let snapshot = makeSnapshot()

        let filtered = snapshot.filtered(searchText: "")

        XCTAssertEqual(filtered.remoteTracks, snapshot.remoteTracks)
        XCTAssertEqual(filtered.availableTracks, snapshot.availableTracks)
    }

    func testOfflineSectionFilteringUsesAvailableOfflineTracks() {
        let snapshot = makeSnapshot()

        let filtered = snapshot.filtered(searchText: "harbor")

        XCTAssertEqual(filtered.remoteTracks.map(\.remoteTrack.trackId), ["remote-harbor-lights"])
        XCTAssertEqual(filtered.availableTracks.map(\.remoteTrackId), ["remote-harbor-lights"])
    }

    func testRemoteSectionFilteringUsesRemoteLibraryTracks() {
        let snapshot = makeSnapshot()

        let filtered = snapshot.filtered(searchText: "shadow")

        XCTAssertEqual(filtered.remoteTracks.map(\.remoteTrack.trackId), ["remote-shadow-city"])
        XCTAssertTrue(filtered.availableTracks.isEmpty)
    }

    func testFilteringDoesNotMutateUnderlyingSnapshotData() {
        let snapshot = makeSnapshot()
        let originalRemoteTracks = snapshot.remoteTracks
        let originalAvailableTracks = snapshot.availableTracks

        _ = snapshot.filtered(searchText: "light")

        XCTAssertEqual(snapshot.remoteTracks, originalRemoteTracks)
        XCTAssertEqual(snapshot.availableTracks, originalAvailableTracks)
    }

    private func makeSnapshot() -> OfflineLibrarySnapshot {
        let remoteTracks = [
            makeRemoteLibraryTrack(
                trackId: "remote-light-trap",
                assetId: "asset-light-trap",
                title: "Light Trap",
                artist: "Unknown Artist",
                isFileAvailable: true
            ),
            makeRemoteLibraryTrack(
                trackId: "remote-shadow-city",
                assetId: "asset-shadow-city",
                title: "Shadow City",
                artist: "Night Runner",
                isFileAvailable: false
            ),
            makeRemoteLibraryTrack(
                trackId: "remote-harbor-lights",
                assetId: "asset-harbor-lights",
                title: "Harbor Lights",
                artist: "The Northline",
                isFileAvailable: true
            ),
        ]

        let availableTracks = [
            makeOfflineTrack(
                trackId: "remote-light-trap",
                assetId: "asset-light-trap",
                title: "Light Trap",
                artist: "Unknown Artist"
            ),
            makeOfflineTrack(
                trackId: "remote-harbor-lights",
                assetId: "asset-harbor-lights",
                title: "Harbor Lights",
                artist: "The Northline"
            ),
        ]

        return OfflineLibrarySnapshot(
            remoteTracks: remoteTracks,
            availableTracks: availableTracks
        )
    }

    private func makeRemoteLibraryTrack(
        trackId: String,
        assetId: String,
        title: String,
        artist: String,
        isFileAvailable: Bool
    ) -> OfflineLibraryRemoteTrack {
        OfflineLibraryRemoteTrack(
            remoteTrack: RemoteTrack(
                trackId: trackId,
                title: title,
                artist: artist,
                durationSeconds: 180,
                sha256: String(repeating: "a", count: 64),
                assetId: assetId,
                createdAt: "2026-05-30T10:00:00.000Z",
                updatedAt: "2026-05-30T10:00:00.000Z"
            ),
            localFilePath: isFileAvailable ? "/tmp/\(assetId).mp3" : "",
            downloadedAt: isFileAvailable ? Date(timeIntervalSince1970: 1_000) : nil,
            isFileAvailable: isFileAvailable,
            status: isFileAvailable ? .downloaded : .notDownloaded,
            lastDownloadError: nil
        )
    }

    private func makeOfflineTrack(
        trackId: String,
        assetId: String,
        title: String,
        artist: String
    ) -> OfflineLibraryTrack {
        OfflineLibraryTrack(
            remoteTrackId: trackId,
            assetId: assetId,
            title: title,
            artist: artist,
            durationSeconds: 180,
            sha256: String(repeating: "b", count: 64),
            localFilePath: "/tmp/\(assetId).mp3",
            downloadedAt: Date(timeIntervalSince1970: 1_000),
            isFileAvailable: true
        )
    }
}