import XCTest

final class ViewDerivedDataTests: XCTestCase {
  func testGenericListViewDerivedCollectionsAreReferencedOncePerRenderPass() throws {
    let source = try loadSource(at: "Sora/Views/Generic/GenericListView.swift")
    let normalizedSource = strippingCommentsAndStrings(from: source)

    let filteredItemsUsages = referenceCount(
      for: "filteredItems",
      in: normalizedSource
    )
    let sortedFilteredItemsUsages = referenceCount(
      for: "sortedFilteredItems",
      in: normalizedSource
    )

    // swiftlint:disable:next prefer_nimble
    XCTAssertLessThanOrEqual(
      filteredItemsUsages,
      1,
      "filteredItems should be consumed once per dependency change."
    )
    // swiftlint:disable:next prefer_nimble
    XCTAssertLessThanOrEqual(
      sortedFilteredItemsUsages,
      1,
      "sortedFilteredItems should be consumed once per dependency change."
    )
  }

  func testPostGridViewDerivedCollectionsAreReferencedOncePerRenderPass() throws {
    let source = try loadSource(at: "Sora/Views/Post/Grid/PostGridView.swift")
    let normalizedSource = strippingCommentsAndStrings(from: source)

    let activePostsUsages = referenceCount(
      for: "activePosts",
      in: normalizedSource
    )
    let getColumnsDataUsages = invocationCount(
      forFunction: "getColumnsData",
      in: normalizedSource
    )

    // swiftlint:disable:next prefer_nimble
    XCTAssertLessThanOrEqual(
      activePostsUsages,
      1,
      "activePosts-derived data should be consumed once per dependency change."
    )
    // swiftlint:disable:next prefer_nimble
    XCTAssertLessThanOrEqual(
      getColumnsDataUsages,
      1,
      "getColumnsData should be invoked once per dependency change."
    )
  }

  func testFavoritesViewDerivedCollectionsAreReferencedOncePerRenderPass() throws {
    let source = try loadSource(at: "Sora/Views/FavoritesView.swift")
    let normalizedSource = strippingCommentsAndStrings(from: source)

    let filteredFavoritesUsages = referenceCount(
      for: "filteredFavorites",
      in: normalizedSource
    )
    let sortedFilteredFavoritesUsages = referenceCount(
      for: "sortedFilteredFavorites",
      in: normalizedSource
    )
    let inlinePostMappingCount = tokenCount(
      matching: #"\bsortedFilteredFavorites\s*\.\s*map\s*\{"#,
      in: normalizedSource
    )
    let columnsSplitterUsages = invocationCount(
      forFunction: "getColumnsData",
      in: normalizedSource
    )

    // swiftlint:disable:next prefer_nimble
    XCTAssertLessThanOrEqual(
      filteredFavoritesUsages,
      1,
      "filteredFavorites should be consumed once per dependency change."
    )
    // swiftlint:disable:next prefer_nimble
    XCTAssertLessThanOrEqual(
      sortedFilteredFavoritesUsages,
      1,
      "sortedFilteredFavorites should be consumed once per dependency change."
    )
    // swiftlint:disable:next prefer_nimble
    XCTAssertEqual(
      inlinePostMappingCount,
      0,
      "Favorites grid should not remap sorted favorites to posts inline on each cell render."
    )
    // swiftlint:disable:next prefer_nimble
    XCTAssertLessThanOrEqual(
      columnsSplitterUsages,
      1,
      "Favorites grid column distribution should be derived once per dependency change."
    )
  }

  func testFolderMenuHierarchyIsSharedAcrossConsumers() throws {
    let consumerPaths = [
      "Sora/Views/Generic/GenericListView.swift",
      "Sora/Views/FavoritesView.swift",
      "Sora/Views/Post/Grid/PostGridView.swift",
      "Sora/Views/BookmarkMenuButtonView.swift",
      "Sora/Views/FavoriteMenuButtonView.swift",
    ]

    for consumerPath in consumerPaths {
      let source = try loadSource(at: consumerPath)
      let sharedMenuUsages = tokenCount(
        matching: #"\bFolderMenuView\s*\("#,
        in: source
      )

      // swiftlint:disable:next prefer_nimble
      XCTAssertGreaterThan(
        sharedMenuUsages,
        0,
        "\(consumerPath) should use FolderMenuView for folder hierarchy rendering."
      )
    }
  }

  func testSearchSuggestionsCacheIsBuiltFromItemsChanges() throws {
    let source = try loadSource(at: "Sora/Views/SearchSuggestionsView.swift")
    let normalizedSource = strippingCommentsAndStrings(from: source)

    let stateCacheCount = tokenCount(
      matching: #"\@State\s+private\s+var\s+cachedTags"#,
      in: normalizedSource
    )
    let itemsMapCount = tokenCount(
      matching: #"\bcachedTags\s*=\s*items\s*\.\s*map"#,
      in: normalizedSource
    )
    let itemsChangeObserverCount = tokenCount(
      matching: #"\.onChange\s*\(\s*of:\s*itemsCacheKey\s*\)"#,
      in: normalizedSource
    )

    // swiftlint:disable:next prefer_nimble
    XCTAssertGreaterThan(
      stateCacheCount,
      0,
      "Search suggestions should keep preprocessed tags in view state."
    )
    // swiftlint:disable:next prefer_nimble
    XCTAssertGreaterThan(
      itemsMapCount,
      0,
      "Search suggestions should build cached tags from items."
    )
    // swiftlint:disable:next prefer_nimble
    XCTAssertGreaterThan(
      itemsChangeObserverCount,
      0,
      "Search suggestions should refresh cached tags only when items change."
    )
  }

  func testPostDetailsImageActionsUseAsyncCachedImageLoading() throws {
    let source = try loadSource(at: "Sora/Views/Post/Details/PostDetailsImageView.swift")
    let normalizedSource = strippingCommentsAndStrings(from: source)

    let synchronousLoadCount = tokenCount(
      matching: #"\bNSData\s*\(\s*contentsOf:"#,
      in: normalizedSource
    )
    let cachedLoaderCount = tokenCount(
      matching: #"\bImageCacheManager\s*\.\s*shared\s*\.\s*loadImageData\s*\("#,
      in: normalizedSource
    )

    // swiftlint:disable:next prefer_nimble
    XCTAssertEqual(
      synchronousLoadCount,
      0,
      "Post details image actions should avoid synchronous NSData file or network loads."
    )
    // swiftlint:disable:next prefer_nimble
    XCTAssertGreaterThan(
      cachedLoaderCount,
      0,
      "Post details image actions should use cache-backed async image loading."
    )
  }

  func testListViewsAvoidComparatorRandomShuffleSorting() throws {
    let listViewSource = try loadSource(at: "Sora/Views/Generic/GenericListView.swift")
    let favoritesViewSource = try loadSource(at: "Sora/Views/FavoritesView.swift")
    let normalizedListViewSource = strippingCommentsAndStrings(from: listViewSource)
    let normalizedFavoritesViewSource = strippingCommentsAndStrings(from: favoritesViewSource)

    let listViewComparatorRandomCount = tokenCount(
      matching: #"\bBool\s*\.\s*random\s*\("#,
      in: normalizedListViewSource
    )
    let favoritesViewComparatorRandomCount = tokenCount(
      matching: #"\bBool\s*\.\s*random\s*\("#,
      in: normalizedFavoritesViewSource
    )

    // swiftlint:disable:next prefer_nimble
    XCTAssertEqual(
      listViewComparatorRandomCount,
      0,
      "Generic list sorting should not use comparator-based random ordering."
    )
    // swiftlint:disable:next prefer_nimble
    XCTAssertEqual(
      favoritesViewComparatorRandomCount,
      0,
      "Favorites sorting should not use comparator-based random ordering."
    )
  }

  func testBooruManagerRemovesUnusedXMLParserPoolPaths() throws {
    let source = try loadSource(at: "Sora/Data/Booru/BooruManager.swift")
    let normalizedSource = strippingCommentsAndStrings(from: source)

    let poolStorageCount = tokenCount(
      matching: #"\bxmlParserPool\b"#,
      in: normalizedSource
    )
    let lockStorageCount = tokenCount(
      matching: #"\bparserPoolLock\b"#,
      in: normalizedSource
    )
    let parserFactoryCount = invocationCount(
      forFunction: "xmlParser",
      in: normalizedSource
    )
    let parserReturnCount = invocationCount(
      forFunction: "returnXMLParser",
      in: normalizedSource
    )

    // swiftlint:disable:next prefer_nimble
    XCTAssertEqual(
      poolStorageCount,
      0,
      "BooruManager should not keep an unused XML parser pool."
    )
    // swiftlint:disable:next prefer_nimble
    XCTAssertEqual(
      lockStorageCount,
      0,
      "BooruManager should not keep an unused parser pool lock."
    )
    // swiftlint:disable:next prefer_nimble
    XCTAssertEqual(
      parserFactoryCount,
      0,
      "BooruManager should not expose unused xml parser factory paths."
    )
    // swiftlint:disable:next prefer_nimble
    XCTAssertEqual(
      parserReturnCount,
      0,
      "BooruManager should not expose unused xml parser return paths."
    )
  }

  private func referenceCount(for symbol: String, in source: String) -> Int {
    let totalMatches = tokenCount(
      matching: #"\b\#(symbol)\b"#,
      in: source
    )
    let declarationMatches = tokenCount(
      matching: #"\b(?:var|let)\s+\#(symbol)\b"#,
      in: source
    )

    return max(0, totalMatches - declarationMatches)
  }

  private func invocationCount(forFunction name: String, in source: String) -> Int {
    let totalMatches = tokenCount(
      matching: #"\b\#(name)\s*\("#,
      in: source
    )
    let declarationMatches = tokenCount(
      matching: #"\bfunc\s+\#(name)\s*\("#,
      in: source
    )

    return max(0, totalMatches - declarationMatches)
  }
}