import XCTest

final class PageNavigationTests: XCTestCase {
    private let app = XCUIApplication()

    override func setUpWithError() throws {
        continueAfterFailure = false
    }

    func testContentAreaExistsForNavigation() {
        app.launchAndOpenSampleBook()
        app.waitForReader()

        let content = app.otherElements[IDs.readerContent]
        XCTAssertTrue(content.waitForExistence(timeout: 5), "阅读内容区域未出现")
    }

    func testPagingViewExistsInScrollMode() {
        app.launchAndOpenSampleBook(displayType: "scroll")
        app.waitForReader()
        app.waitForDemoReaderState(timeout: 5, description: "display=horizontalScroll") { $0.display == "horizontalScroll" }

        let paging = app.collectionViews[IDs.readerPaging]
        XCTAssertTrue(paging.waitForExistence(timeout: 5), "分页滚动视图未出现")
    }

    func testPagingViewExistsInVerticalScrollMode() {
        app.launchAndOpenSampleBook(displayType: "vertical")
        app.waitForReader()
        app.waitForDemoReaderState(timeout: 5, description: "display=verticalScroll") { $0.display == "verticalScroll" }

        let paging = app.collectionViews[IDs.readerPaging]
        XCTAssertTrue(paging.waitForExistence(timeout: 5), "分页滚动视图未出现")
    }

    func testSwipeInHorizontalScrollMode() {
        app.launchAndOpenSampleBook(displayType: "scroll")
        app.waitForReader()
        app.waitForDemoReaderState(timeout: 5, description: "display=horizontalScroll") { $0.display == "horizontalScroll" }

        let paging = app.collectionViews[IDs.readerPaging]
        XCTAssertTrue(paging.waitForExistence(timeout: 5))

        let beforeState = app.waitForDemoReaderState(timeout: 5, description: "滑动前页码") { $0.page != nil }
        let beforePage = beforeState.page ?? 0

        paging.swipeLeft()
        let afterState = app.waitForDemoReaderState(timeout: 8, description: "水平滑动后页码变化") { state in
            guard let page = state.page else { return false }
            return page != beforePage
        }
        XCTAssertNotEqual(beforePage, afterState.page, "水平滑动后页码未变化")
    }

    func testSwipeRightReturnsToPreviousPage() {
        app.launchAndOpenSampleBook(displayType: "scroll", pageNumber: 3)
        app.waitForReader()
        app.waitForDemoReaderState(timeout: 8, description: "page=3") { $0.page == 3 }

        let paging = app.collectionViews[IDs.readerPaging]
        XCTAssertTrue(paging.waitForExistence(timeout: 5))
        paging.swipeRight()

        let state = app.waitForDemoReaderState(timeout: 8, description: "returned to previous page") { state in
            guard let page = state.page else { return false }
            return page < 3
        }
        XCTAssertEqual(state.page, 2, "向右滑动后应回到上一页")
    }

    func testLaunchAtSpecificPageNumber() {
        app.launchAndOpenSampleBook(pageNumber: 4)
        app.waitForReader()
        app.waitForDemoReaderState(timeout: 8, description: "page=4") { $0.page == 4 }
    }
}