#if os(macOS)
import AppKit
import XCTest
@testable import DocsKit

@MainActor final class DocumentPageEditingTests: XCTestCase {
    func testOptimisticAndMarkedEditsInvalidatePageOffsets() throws {
        let nodes = (0..<100).map { index in
            CRDTNode(id: "p\(index)", type: "paragraph", children: [CRDTNode(id: "t\(index)", type: "text", runs: [CRDTRun(insert: "A paragraph kept together when pages are recalculated.")])])
        }
        let view = DocsPagedTextView(frame: CGRect(x: 0, y: 0, width: 636, height: 800))
        let storage = try XCTUnwrap(view.textStorage)
        storage.setAttributedString(NativeTextProjection.render(CRDTProjection(children: nodes, canUndo: false, canRedo: false)))
        view.paged = true
        view.layout()
        let container = try XCTUnwrap(view.textContainer as? DocsPageTextContainer)
        XCTAssertFalse(container.blockStarts.isEmpty)
        let initial = container.blockStarts
        let insertion = String(repeating: "Inserted text before the boundary. ", count: 20)
        storage.replaceCharacters(in: NSRange(location: 0, length: 0), with: insertion)
        assertBlockStarts(container, storage)
        view.layout()
        XCTAssertNotEqual(initial, container.blockStarts)
        assertBlockStarts(container, storage)
        view.setSelectedRange(NSRange(location: 0, length: 0))
        view.setMarkedText("日本語", selectedRange: NSRange(location: 3, length: 0), replacementRange: NSRange(location: 0, length: 0))
        assertBlockStarts(container, storage)
        view.layout()
        assertBlockStarts(container, storage)
        view.unmarkText()
        storage.replaceCharacters(in: NSRange(location: 0, length: 3 + insertion.utf16.count), with: "")
        assertBlockStarts(container, storage)
        view.layout()
        XCTAssertEqual(container.blockStarts, initial)
        XCTAssertEqual(storage.string, nodes.map(\.plainText).joined(separator: "\n") + "\n")
    }

    func testMetadataReconciliationNeverExposesUnpaginatedCaretGeometry() throws {
        let nodes = (0..<1000).map { index in
            CRDTNode(id: "p\(index)", type: "paragraph", children: [CRDTNode(id: "t\(index)", type: "text", runs: [CRDTRun(insert: "A paragraph kept together when pages are recalculated.")])])
        }
        let view = DocsPagedTextView(frame: CGRect(x: 0, y: 0, width: 636, height: 800))
        let storage = try XCTUnwrap(view.textStorage)
        storage.setAttributedString(NativeTextProjection.render(CRDTProjection(children: nodes, canUndo: false, canRedo: false)))
        view.paged = true
        view.layout()
        let manager = try XCTUnwrap(view.layoutManager)
        let container = try XCTUnwrap(view.textContainer as? DocsPageTextContainer)
        XCTAssertGreaterThanOrEqual(container.blockStarts.count, 2)
        let selected = storage.length - 3
        view.setSelectedRange(NSRange(location: selected, length: 0))
        func caretY() -> CGFloat {
            manager.ensureLayout(for: container)
            return manager.lineFragmentRect(forGlyphAt: manager.glyphIndexForCharacter(at: selected), effectiveRange: nil).minY
        }
        let before = caretY()
        let start = ContinuousClock.now
        for generation in 0..<10 {
            storage.addAttribute(NSAttributedString.Key("MetadataOnly"), value: generation, range: NSRange(location: 0, length: storage.length))
            XCTAssertEqual(caretY(), before, accuracy: 0.01, "AppKit can query the caret before the next view layout")
        }
        print("Ten metadata updates in a 1,000-paragraph document:", start.duration(to: .now))
        view.layout()
        XCTAssertEqual(caretY(), before, accuracy: 0.01)
        XCTAssertEqual(view.selectedRange(), NSRange(location: selected, length: 0))
    }

    func testCaretBackgroundErasureStaysInsideRequestedRectangle() throws {
        let view = DocsPagedTextView(frame: CGRect(x: 0, y: 0, width: 636, height: 800))
        view.layout()
        let bitmap = try XCTUnwrap(NSBitmapImageRep(bitmapDataPlanes: nil, pixelsWide: 100, pixelsHigh: 100,
            bitsPerSample: 8, samplesPerPixel: 4, hasAlpha: true, isPlanar: false,
            colorSpaceName: .deviceRGB, bytesPerRow: 0, bitsPerPixel: 0))
        let context = try XCTUnwrap(NSGraphicsContext(bitmapImageRep: bitmap))
        NSGraphicsContext.saveGraphicsState()
        defer { NSGraphicsContext.restoreGraphicsState() }
        NSGraphicsContext.current = context
        NSColor.red.setFill()
        CGRect(x: 0, y: 0, width: 100, height: 100).fill()
        view.drawBackground(in: CGRect(x: 40, y: 40, width: 20, height: 20))
        XCTAssertEqual(try XCTUnwrap(bitmap.colorAt(x: 20, y: 20)).greenComponent, 0, accuracy: 0.01,
                       "Erasing one caret must not paint over neighboring glyphs")
        XCTAssertGreaterThan(try XCTUnwrap(bitmap.colorAt(x: 50, y: 50)).greenComponent, 0.9)
    }

    func testTypingKeepsCaretInsidePageBoundsWithStableOrigin() throws {
        let nodes = (0..<60).map { index in
            CRDTNode(id: "p\(index)", type: "paragraph", children: [CRDTNode(id: "t\(index)", type: "text", runs: [CRDTRun(insert: String(repeating: "A paragraph that wraps across lines. ", count: 8))])])
        }
        let view = DocsTextView(frame: CGRect(x: 0, y: 0, width: 900, height: 800))
        view.textStorage!.setAttributedString(NativeTextProjection.render(CRDTProjection(children: nodes, canUndo: false, canRedo: false)))
        view.paged = true
        view.layout()
        view.setSelectedRange(NSRange(location: view.string.utf16.count - 1, length: 0))
        for text in ["\n", "a", "\n", "b"] {
            view.insertText(text, replacementRange: view.selectedRange())
            view.layoutManager!.ensureLayout(for: view.textContainer!)
            let glyph = view.layoutManager!.glyphIndexForCharacter(at: view.selectedRange().location)
            let line = view.layoutManager!.lineFragmentRect(forGlyphAt: glyph, effectiveRange: nil)
            XCTAssertEqual(view.textContainerOrigin, .zero)
            XCTAssertGreaterThanOrEqual(view.bounds.maxY, line.maxY)
        }
    }

    private func assertBlockStarts(_ container: DocsPageTextContainer, _ storage: NSTextStorage) {
        for location in container.blockStarts.keys {
            var range = NSRange()
            XCTAssertNotNil(storage.attribute(.docsTopBlock, at: location, effectiveRange: &range))
            XCTAssertEqual(range.location, location, "A separator must never move into a paragraph")
        }
    }
}
#endif