import SwiftUI
import AppKit
import VorleserKit

struct BookTextView: NSViewRepresentable {
	let attributedText: NSAttributedString
	let highlightRange: Range<Int>?
	let onClickCharacter: (CharacterOffset) -> Void
	var scrollToOffset: CharacterOffset?

	func makeNSView(context: Context) -> NSScrollView {
		let scrollView = NSTextView.scrollableTextView()
		let textView = scrollView.documentView as! NSTextView
		textView.isEditable = false
		textView.isSelectable = false
		textView.textContainerInset = NSSize(width: 16, height: 16)

		let click = NSClickGestureRecognizer(target: context.coordinator, action: #selector(Coordinator.handleClick(_:)))
		textView.addGestureRecognizer(click)
		context.coordinator.textView = textView

		return scrollView
	}

	func updateNSView(_ scrollView: NSScrollView, context: Context) {
		guard let textView = scrollView.documentView as? NSTextView else { return }

		let highlighted = NSMutableAttributedString(attributedString: attributedText)

		if let range = highlightRange,
		   range.lowerBound >= 0,
		   range.upperBound <= attributedText.length {
			let nsRange = NSRange(location: range.lowerBound, length: range.upperBound - range.lowerBound)
			highlighted.addAttribute(.backgroundColor, value: NSColor.systemYellow.withAlphaComponent(0.3), range: nsRange)
		}

		textView.textStorage?.setAttributedString(highlighted)

		if let range = highlightRange,
		   range.lowerBound >= 0,
		   range.upperBound <= attributedText.length {
			let nsRange = NSRange(location: range.lowerBound, length: range.upperBound - range.lowerBound)
			textView.scrollRangeToVisible(nsRange)
		}

		if let offset = scrollToOffset,
		   offset >= 0,
		   offset < attributedText.length {
			let nsRange = NSRange(location: offset, length: 1)
			textView.scrollRangeToVisible(nsRange)
		}
	}

	func makeCoordinator() -> Coordinator {
		Coordinator(onClickCharacter: onClickCharacter)
	}

	class Coordinator: NSObject {
		weak var textView: NSTextView?
		let onClickCharacter: (CharacterOffset) -> Void

		init(onClickCharacter: @escaping (CharacterOffset) -> Void) {
			self.onClickCharacter = onClickCharacter
		}

		@objc func handleClick(_ gesture: NSClickGestureRecognizer) {
			guard let textView else { return }
			let point = gesture.location(in: textView)
			let characterIndex = textView.characterIndexForInsertion(at: point)
			if characterIndex < textView.string.count {
				onClickCharacter(characterIndex)
			}
		}
	}
}