import XCTest

final class LargeBookOnDemandTests: XCTestCase {
    private let app = XCUIApplication()
    private let largeBookQuery = "凡人修仙传"

    override func setUpWithError() throws {
        continueAfterFailure = false
    }

    func testLargeBookInitialOpenIsReadableWhilePaginationIsPartial() throws {
        app.launchAndOpenSampleBook(bookTitleQuery: largeBookQuery, resetsReaderState: true)
        app.waitForReader(timeout: 20)

        let partialState = app.waitForDemoReaderState(timeout: 15, description: "大书首开进入局部分页") { state in
            state.mode == "bookPageMap" && state.pagination == "partial" && (state.page ?? 0) >= 1
        }

        XCTAssertEqual(partialState.mode, "bookPageMap")
        XCTAssertEqual(partialState.pagination, "partial")
        XCTAssertTrue(app.otherElements[IDs.readerContent].waitForExistence(timeout: 5), "首开局部分页阶段应已可阅读")
    }

    func testLargeBookBackgroundPaginationProgresses() throws {
        app.launchAndOpenSampleBook(bookTitleQuery: largeBookQuery, resetsReaderState: true)
        app.waitForReader(timeout: 20)

        let initialState = app.waitForDemoReaderState(timeout: 15, description: "获取初始分页进度") { state in
            state.mode == "bookPageMap" && state.knownChapters != nil && state.buildableChapters != nil
        }
        let initialKnownChapters = initialState.knownChapters ?? 0
        let initialKnownPages = initialState.knownPages ?? 0

        let progressedState = app.waitForDemoReaderState(timeout: 45, description: "后台分页推进") { state in
            guard state.mode == "bookPageMap" else { return false }
            if state.pagination == "full" {
                return true
            }
            return (state.knownChapters ?? 0) > initialKnownChapters || (state.knownPages ?? 0) > initialKnownPages
        }

        XCTAssertEqual(progressedState.mode, "bookPageMap")
        XCTAssertTrue(
            (progressedState.knownChapters ?? 0) >= initialKnownChapters ||
            (progressedState.knownPages ?? 0) >= initialKnownPages
        )
    }

    func testLargeBookSecondOpenRestoresFromCache() throws {
        app.launchAndOpenSampleBook(bookTitleQuery: largeBookQuery, resetsReaderState: true)
        app.waitForReader(timeout: 20)

        _ = app.waitForDemoReaderState(timeout: 60, description: "首次打开完成全书缓存") { state in
            state.mode == "bookPageMap" && state.pagination == "full" && (state.buildableChapters ?? 0) > 0
        }

        app.showReaderChromeIfNeeded()
        XCTAssertTrue(app.buttons[IDs.readerBack].waitForExistence(timeout: 5), "返回按钮不存在")
        app.buttons[IDs.readerBack].tap()
        XCTAssertTrue(app.tables[IDs.demoBooksTable].waitForExistence(timeout: 5), "书架列表未出现")

        app.launchAndOpenSampleBook(bookTitleQuery: largeBookQuery, resetsReaderState: false)
        app.waitForReader(timeout: 15)

        let reopenedState = app.waitForDemoReaderState(timeout: 10, description: "二开直接恢复完整缓存") { state in
            state.mode == "bookPageMap" && state.pagination == "full" && (state.knownChapters ?? 0) == (state.buildableChapters ?? -1)
        }

        XCTAssertEqual(reopenedState.pagination, "full")
        XCTAssertEqual(reopenedState.knownChapters, reopenedState.buildableChapters)
    }

    func testLargeBookContinuousPagingExtendsKnownPageMap() throws {
        app.launchAndOpenSampleBook(bookTitleQuery: largeBookQuery, displayType: "scroll", resetsReaderState: true)
        app.waitForReader(timeout: 20)
        app.waitForReaderState(containing: "display=horizontalScroll", timeout: 8)

        let initialState = app.waitForDemoReaderState(timeout: 15, description: "初始局部分页") { state in
            state.mode == "bookPageMap" && state.knownPages != nil && state.page != nil
        }
        let initialKnownPages = initialState.knownPages ?? 0
        let initialPage = initialState.page ?? 0

        let paging = app.collectionViews[IDs.readerPaging]
        XCTAssertTrue(paging.waitForExistence(timeout: 5), "分页视图不存在")

        for _ in 0..<4 {
            paging.swipeLeft()
        }

        let extendedState = app.waitForDemoReaderState(timeout: 20, description: "连续翻页触发扩窗") { state in
            guard state.mode == "bookPageMap" else { return false }
            let pageAdvanced = (state.page ?? 0) > initialPage
            let pageMapExtended = (state.knownPages ?? 0) > initialKnownPages || state.pagination == "full"
            return pageAdvanced && pageMapExtended
        }

        XCTAssertTrue((extendedState.page ?? 0) > initialPage, "连续翻页后当前页应向后推进")
        XCTAssertTrue(
            (extendedState.knownPages ?? 0) > initialKnownPages || extendedState.pagination == "full",
            "连续翻页后已知页图应扩窗或直接完成全量分页"
        )
    }
}