import XCTest
@testable import AIStudyApp

final class ReadingPositionAdapterTests: XCTestCase {

    private func makeValue(
        type: String?,
        blockId: String? = nil,
        blockProgress: Float? = nil,
        lineNumber: UInt32? = nil,
        pageNumber: UInt32? = nil,
        scrollProgress: Float? = nil,
        pageProgress: Float? = nil,
        overallProgress: Float? = nil,
        zoomScale: Float? = nil,
        offsetX: Float? = nil,
        offsetY: Float? = nil,
        chapterId: String? = nil,
        chapterProgress: Float? = nil
    ) -> ReadingPositionValue {
        ReadingPositionValue(
            type: type,
            pageNumber: pageNumber,
            blockId: blockId,
            blockProgress: blockProgress,
            scrollProgress: scrollProgress,
            lineNumber: lineNumber,
            pageProgress: pageProgress,
            overallProgress: overallProgress,
            zoomScale: zoomScale,
            offsetX: offsetX,
            offsetY: offsetY,
            chapterId: chapterId,
            chapterProgress: chapterProgress,
            offset: nil,
            percent: nil,
            section: nil
        )
    }

    func test_fromValue_markdown_with_blockId() {
        let v = makeValue(type: "Markdown", blockId: "b1", scrollProgress: 0.5)
        let pos = ReadingPositionAdapter.fromValue(v)
        guard case let .markdown(blockId, scrollProgress) = pos else {
            return XCTFail("Expected .markdown, got \(String(describing: pos))")
        }
        XCTAssertEqual(blockId, "b1")
        XCTAssertEqual(scrollProgress, 0.5)
    }

    func test_fromValue_markdown_nil_blockId_returns_nil() {
        let v = makeValue(type: "Markdown")
        XCTAssertNil(ReadingPositionAdapter.fromValue(v))
    }

    func test_fromValue_text_with_optional_fields() {
        let v = makeValue(type: "Text", lineNumber: 42, scrollProgress: 0.8)
        guard case let .text(lineNumber, scrollProgress) = ReadingPositionAdapter.fromValue(v) else {
            return XCTFail("Expected .text")
        }
        XCTAssertEqual(lineNumber, 42)
        XCTAssertEqual(scrollProgress, 0.8)
    }

    func test_fromValue_pdf_with_all_fields() {
        let v = makeValue(type: "Pdf", pageNumber: 5, pageProgress: 0.3, overallProgress: 0.15)
        guard case let .pdf(pageNumber, pageProgress, overallProgress) = ReadingPositionAdapter.fromValue(v) else {
            return XCTFail("Expected .pdf")
        }
        XCTAssertEqual(pageNumber, 5)
        XCTAssertEqual(pageProgress, 0.3)
        XCTAssertEqual(overallProgress, 0.15)
    }

    func test_fromBlockScroll_markdown_returns_position() {
        let blocks: [DocumentBlock] = [
            .heading(id: "h1", level: 1, text: "Title"),
            .paragraph(id: "p1", text: "Content"),
        ]
        let pos = ReadingPositionAdapter.fromBlockScroll(
            materialType: .markdown, blocks: blocks, scrollProgress: 0.5, blockIndex: 0
        )
        guard case .block(let blockId, let blockProgress, let overallProgress) = pos else {
            return XCTFail("Expected .block")
        }
        XCTAssertEqual(blockId, "h1")
        XCTAssertEqual(blockProgress, 0.5)
        XCTAssertEqual(overallProgress, 0.5)
    }

    func test_blockIdForRestore_prefers_existing_blockId() {
        let blocks: [DocumentBlock] = [
            .heading(id: "h1", level: 1, text: "Title"),
            .paragraph(id: "p1", text: "Content"),
            .paragraph(id: "p2", text: "Tail"),
        ]

        let restored = ReadingPositionAdapter.blockIdForRestore(
            from: .block(blockId: "p1", blockProgress: 0.25, overallProgress: 0.8),
            in: blocks
        )

        XCTAssertEqual(restored, "p1")
    }

    func test_blockIdForRestore_fallsBack_to_progress_when_blockId_missing() {
        let blocks: [DocumentBlock] = [
            .heading(id: "h1", level: 1, text: "Title"),
            .paragraph(id: "p1", text: "Content"),
            .paragraph(id: "p2", text: "Tail"),
        ]

        let restored = ReadingPositionAdapter.blockIdForRestore(
            from: .block(blockId: "missing", blockProgress: 0.1, overallProgress: 0.9),
            in: blocks
        )

        XCTAssertEqual(restored, "p2")
    }

    func test_blockIdForRestore_text_out_of_range_fallsBack_to_scroll_progress() {
        let blocks: [DocumentBlock] = [
            .heading(id: "h1", level: 1, text: "Title"),
            .paragraph(id: "p1", text: "Content"),
            .paragraph(id: "p2", text: "Tail"),
        ]

        let restored = ReadingPositionAdapter.blockIdForRestore(
            from: .text(lineNumber: 99, scrollProgress: 0.45),
            in: blocks
        )

        XCTAssertEqual(restored, "p1")
    }
}