import AppKit
import ConjureKit
import Testing
@testable import Conjure

@Test @MainActor
func headingsFollowVisibleParagraphEditingAndRoundTrip() throws {
    _ = NSApplication.shared
    let suite = "NotesHeadings.\(UUID().uuidString)"
    let defaults = try #require(UserDefaults(suiteName: suite))
    let directory = FileManager.default.temporaryDirectory.appendingPathComponent(suite)
    defer {
        defaults.removePersistentDomain(forName: suite)
        try? FileManager.default.removeItem(at: directory)
    }
    let controller = NotesController(defaults: defaults, directory: directory)
    let window = NSWindow(contentRect: NSRect(x: 0, y: 0, width: 600, height: 500),
        styleMask: .borderless, backing: .buffered, defer: false)
    window.contentViewController = controller
    defer { _ = controller.close(); window.orderOut(nil) }
    func descendants(_ view: NSView) -> [NSView] { [view] + view.subviews.flatMap(descendants) }
    let editor = try #require(descendants(controller.view).compactMap { $0 as? NotesTextView }.first)
    window.makeFirstResponder(editor)
    func reset(_ source: String) {
        editor.setMarkdownContents(NSAttributedString(string: source))
        MarkdownHighlighting.apply(to: editor)
        editor.refreshTasks()
        editor.breakUndoCoalescing()
        editor.undoManager?.removeAllActions()
        let title = (editor.string as NSString).range(of: "Title")
        editor.setSelectedRange(NSRange(location: title.location, length: 0))
    }
    for (before, after) in [
        ("## Title", "## Title"),
        ("\n## Title", "## Title"),
        ("Text\n## Title", "TextTitle"),
        ("# Text\n## Title", "# TextTitle"),
        ("Text\n\n## Title", "Text\n## Title")
    ] {
        reset(before)
        editor.undoManager?.beginUndoGrouping()
        editor.deleteBackward(nil)
        editor.undoManager?.endUndoGrouping()
        #expect(editor.markdownString == after)
        if before != after {
            editor.undoManager?.undo()
            #expect(editor.markdownString == before)
            editor.undoManager?.redo()
            #expect(editor.markdownString == after)
        }
    }
    for level in 1...6 {
        reset("### Title")
        editor.undoManager?.beginUndoGrouping()
        for character in String(repeating: "#", count: level) + " " {
            editor.insertText(String(character), replacementRange: editor.selectedRange())
        }
        editor.undoManager?.endUndoGrouping()
        let expected = String(repeating: "#", count: level) + " Title"
        #expect(editor.markdownString == expected)
        let title = (editor.string as NSString).range(of: "Title")
        #expect(editor.selectedRange().location == title.location)
        let sizes: [CGFloat] = [26, 23, 21, 19, 17, 15]
        #expect((editor.textStorage?.attribute(.font, at: title.location, effectiveRange: nil) as? NSFont)?.pointSize == sizes[level - 1])
        editor.undoManager?.undo()
        #expect(editor.markdownString == "### Title")
        editor.undoManager?.redo()
        #expect(editor.markdownString == expected)
        #expect(controller.save())
        let reloaded = try #require(NotesStore(directory: directory).notes.first)
        #expect(reloaded.contents.string == expected)
    }
    reset("```text\n## Title\n```")
    editor.insertText("# ", replacementRange: editor.selectedRange())
    #expect(editor.markdownString == "```text\n## # Title\n```")
}