import SwiftUI
#if os(macOS)
import AppKit
struct NativeDocumentTextView: NSViewRepresentable {
    let content: NSAttributedString
    let generation: UInt64
    let didRender: @MainActor (UInt64) -> Void
    let compositionChanged: @MainActor (Bool) -> Void
    let isEditable: Bool
    let paged: Bool
    let pendingInput: Bool
    let canRender: @MainActor (UInt64) -> Bool
    let currentSelection: @MainActor () -> NSRange
    @Binding var selection: NSRange
    let edit: @MainActor ([String: JSONValue]) -> Bool
    var action: @MainActor (String) -> Bool = { _ in false }
    var selectionMoved: @MainActor () -> Void = {}
    var canAction: @MainActor (String) -> Bool = { _ in false }
    var explicitCommandRevision: UInt64 = 0
    var zoom: Double = 1
    func makeCoordinator() -> Coordinator { Coordinator(self) }
    func makeNSView(context: Context) -> NSScrollView {
        let scroll = NSScrollView()
        scroll.hasVerticalScroller = true
        scroll.hasHorizontalScroller = true
        scroll.minMagnification = 0.5
        scroll.maxMagnification = 3
        scroll.allowsMagnification = false
        scroll.magnification = 4.0 / 3.0
        let text = DocsTextView(frame: .zero)
        text.isVerticallyResizable = false
        text.autoresizingMask = [.width]
        scroll.documentView = text
        text.delegate = context.coordinator
        let coordinator = context.coordinator
        text.action = { [weak text] action in
            text?.lastInputRule = nil
            return coordinator.parent.action(action)
        }
        text.canAction = { coordinator.parent.canAction($0) }
        text.ruleCommand = coordinator.ruleEdit
        text.clipboardEdit = { blocks, range, replacement in coordinator.clipboardEdit(blocks: blocks, range: range, replacement: replacement) }
        text.compositionChanged = { coordinator.parent.compositionChanged($0) }
        text.compositionCommitted = { before, after in coordinator.commitComposition(before: before, after: after) }
        text.isRichText = true
        text.isAutomaticLinkDetectionEnabled = false
        text.isAutomaticTextReplacementEnabled = false
        text.allowsUndo = false
        text.setAccessibilityIdentifier("docs.editor")
        text.setAccessibilityLabel(String(localized: "native.editor", bundle: DocsResources.bundle))
        return scroll
    }
    func updateNSView(_ scroll: NSScrollView, context: Context) {
        guard let text = scroll.documentView as? NSTextView else { return }
        let magnification = zoom * 4.0 / 3.0
        if abs(scroll.magnification - magnification) > 0.001 {
            scroll.setMagnification(magnification, centeredAt: scroll.contentView.bounds.origin)
            text.needsLayout = true
        }
        context.coordinator.applyRender(self, to: text)
    }
    @MainActor final class Coordinator: NSObject, NSTextViewDelegate {
        var parent: NativeDocumentTextView
        var rendered: NSAttributedString?
        var generation: UInt64 = 0
        var expectedSelection: NSRange?
        var applying = false
        var explicitCommandRevision: UInt64 = 0
        init(_ parent: NativeDocumentTextView) { self.parent = parent }
        func applyRender(_ candidate: NativeDocumentTextView, to text: NSTextView) {
            parent = candidate
            if candidate.explicitCommandRevision > explicitCommandRevision {
                explicitCommandRevision = candidate.explicitCommandRevision
                (text as? DocsTextView)?.lastInputRule = nil
            }
            text.isEditable = candidate.isEditable
            (text as? DocsTextView)?.paged = candidate.paged
            // pendingInput makes SwiftUI observe drain completion; only this live
            // callback can authorize a delayed candidate at application time.
            guard candidate.canRender(candidate.generation), !text.hasMarkedText() else { return }
            let newGeneration = generation != candidate.generation
            guard newGeneration || (rendered?.isEqual(to: candidate.content) != true && text.string == candidate.content.string) else { return }
            let selected = newGeneration ? candidate.currentSelection() : text.selectedRange()
            applying = true
            defer { applying = false }
            rendered = NSAttributedString(attributedString: candidate.content)
            generation = candidate.generation
            if let storage = text.textStorage { DocumentRenderReconciliation.apply(candidate.content, to: storage) }
            let range = NSRange(location: min(selected.location, candidate.content.length), length: min(selected.length, max(0, candidate.content.length - selected.location)))
            if text.selectedRange() != range { text.setSelectedRange(range) }
            candidate.didRender(candidate.generation)
        }
        func ruleEdit(_ command: [String: JSONValue]) -> Bool {
            var command = command; command["generation"] = .number(Double(generation))
            let accepted = parent.edit(command)
            if accepted, case .number(let at)? = command["at"] {
                let inserted: Int
                if command["op"] == .string("display_revert_rule"), case .string(let text)? = command["text"] { inserted = text.utf16.count } else { inserted = 0 }
                expectedSelection = NSRange(location: Int(at) + inserted, length: 0)
            }
            return accepted
        }
        func clipboardEdit(blocks: [JSONValue]?, range: NSRange, replacement: String) -> Bool {
            var command: [String: JSONValue] = ["op": .string(blocks == nil ? "display_edit" : "display_paste"), "at": .number(Double(range.location)), "length": .number(Double(range.length)), "generation": .number(Double(generation))]
            if let blocks { command["blocks"] = .array(blocks) } else { command["text"] = .string(replacement) }
            let accepted = parent.edit(command)
            if accepted { expectedSelection = NSRange(location: range.location + replacement.utf16.count, length: 0) }
            return accepted
        }
        func commitComposition(before: NSAttributedString, after: String) -> Bool {
            guard let (range, replacement) = DocumentComposition.replacement(before: before.string, after: after) else { return true }
            guard var command = TextEditMapping.displayCommand(in: before, range: range, replacement: replacement) else { return false }
            command["generation"] = .number(Double(generation))
            let accepted = parent.edit(command)
            if accepted { expectedSelection = NSRange(location: range.location + replacement.utf16.count, length: 0) }
            return accepted
        }
        func textView(_ textView: NSTextView, shouldChangeTextIn affectedCharRange: NSRange, replacementString: String?) -> Bool {
            if (textView as? DocsTextView)?.isComposing == true { return true }
            if let replacementString, (textView as? DocsTextView)?.interceptInput(replacementString, range: affectedCharRange) == true { return false }
            guard let replacementString, var command = TextEditMapping.displayCommand(in: textView.attributedString(), range: affectedCharRange, replacement: replacementString) else { return false }
            command["generation"] = .number(Double(generation))
            let accepted = parent.edit(command)
            if accepted { expectedSelection = NSRange(location: affectedCharRange.location + replacementString.utf16.count, length: 0) }
            return accepted
        }
        func textViewDidChangeSelection(_ notification: Notification) {
            guard let text = notification.object as? NSTextView else { return }
            guard !applying else { return }
            let selected = text.selectedRange()
            if selected.length == 0 && selected.location == text.string.utf16.count && text.string.hasSuffix("\n") {
                text.setSelectedRange(NSRange(location: max(0, selected.location - 1), length: 0)); return
            }
            if !applying, (text as? DocsTextView)?.isComposing != true {
                if selected != expectedSelection && selected != parent.selection {
                    parent.selectionMoved()
                    (text as? DocsTextView)?.lastInputRule = nil
                }
                expectedSelection = nil
            }
            parent.selection = selected
        }
    }
}
#else
import UIKit
struct NativeDocumentTextView: UIViewRepresentable {
    let content: NSAttributedString
    let generation: UInt64
    let didRender: @MainActor (UInt64) -> Void
    let compositionChanged: @MainActor (Bool) -> Void
    let isEditable: Bool
    let paged: Bool
    let pendingInput: Bool
    let canRender: @MainActor (UInt64) -> Bool
    let currentSelection: @MainActor () -> NSRange
    @Binding var selection: NSRange
    let edit: @MainActor ([String: JSONValue]) -> Bool
    var action: @MainActor (String) -> Bool = { _ in false }
    var selectionMoved: @MainActor () -> Void = {}
    var canAction: @MainActor (String) -> Bool = { _ in false }
    var explicitCommandRevision: UInt64 = 0
    var zoom: Double = 1
    func makeCoordinator() -> Coordinator { Coordinator(self) }
    func makeUIView(context: Context) -> UITextView {
        let text = DocsTextView()
        text.delegate = context.coordinator
        let coordinator = context.coordinator
        text.action = { [weak text] action in
            text?.lastInputRule = nil
            return coordinator.parent.action(action)
        }
        text.canAction = { coordinator.parent.canAction($0) }
        text.ruleCommand = coordinator.ruleEdit
        text.clipboardEdit = { blocks, range, replacement in coordinator.clipboardEdit(blocks: blocks, range: range, replacement: replacement) }
        text.compositionChanged = { coordinator.parent.compositionChanged($0) }
        text.compositionCommitted = { before, after in coordinator.commitComposition(before: before, after: after) }
        text.adjustsFontForContentSizeCategory = true
        text.accessibilityIdentifier = "docs.editor"
        text.accessibilityLabel = String(localized: "native.editor", bundle: DocsResources.bundle)
        return text
    }
    func updateUIView(_ text: UITextView, context: Context) {
        context.coordinator.applyRender(self, to: text)
    }
    @MainActor final class Coordinator: NSObject, UITextViewDelegate {
        var parent: NativeDocumentTextView
        var rendered: NSAttributedString?
        var generation: UInt64 = 0
        var expectedSelection: NSRange?
        var applying = false
        var explicitCommandRevision: UInt64 = 0
        init(_ parent: NativeDocumentTextView) { self.parent = parent }
        func applyRender(_ candidate: NativeDocumentTextView, to text: UITextView) {
            parent = candidate
            if candidate.explicitCommandRevision > explicitCommandRevision {
                explicitCommandRevision = candidate.explicitCommandRevision
                (text as? DocsTextView)?.lastInputRule = nil
            }
            text.isEditable = candidate.isEditable
            (text as? DocsTextView)?.paged = candidate.paged
            guard candidate.canRender(candidate.generation), text.markedTextRange == nil else { return }
            let newGeneration = generation != candidate.generation
            guard newGeneration || (rendered?.isEqual(to: candidate.content) != true && text.text == candidate.content.string) else { return }
            let selected = newGeneration ? candidate.currentSelection() : text.selectedRange
            applying = true
            defer { applying = false }
            rendered = NSAttributedString(attributedString: candidate.content)
            generation = candidate.generation
            text.attributedText = candidate.content
            text.selectedRange = NSRange(location: min(selected.location, candidate.content.length), length: min(selected.length, max(0, candidate.content.length - selected.location)))
            candidate.didRender(candidate.generation)
        }
        func ruleEdit(_ command: [String: JSONValue]) -> Bool {
            var command = command; command["generation"] = .number(Double(generation))
            let accepted = parent.edit(command)
            if accepted, case .number(let at)? = command["at"] {
                let inserted: Int
                if command["op"] == .string("display_revert_rule"), case .string(let text)? = command["text"] { inserted = text.utf16.count } else { inserted = 0 }
                expectedSelection = NSRange(location: Int(at) + inserted, length: 0)
            }
            return accepted
        }
        func clipboardEdit(blocks: [JSONValue]?, range: NSRange, replacement: String) -> Bool {
            var command: [String: JSONValue] = ["op": .string(blocks == nil ? "display_edit" : "display_paste"), "at": .number(Double(range.location)), "length": .number(Double(range.length)), "generation": .number(Double(generation))]
            if let blocks { command["blocks"] = .array(blocks) } else { command["text"] = .string(replacement) }
            let accepted = parent.edit(command)
            if accepted { expectedSelection = NSRange(location: range.location + replacement.utf16.count, length: 0) }
            return accepted
        }
        func commitComposition(before: NSAttributedString, after: String) -> Bool {
            guard let (range, replacement) = DocumentComposition.replacement(before: before.string, after: after) else { return true }
            guard var command = TextEditMapping.displayCommand(in: before, range: range, replacement: replacement) else { return false }
            command["generation"] = .number(Double(generation))
            let accepted = parent.edit(command)
            if accepted { expectedSelection = NSRange(location: range.location + replacement.utf16.count, length: 0) }
            return accepted
        }
        func textView(_ textView: UITextView, shouldChangeTextIn range: NSRange, replacementText text: String) -> Bool {
            if (textView as? DocsTextView)?.isComposing == true { return true }
            if (textView as? DocsTextView)?.interceptInput(text, range: range) == true { return false }
            guard var command = TextEditMapping.displayCommand(in: textView.attributedText, range: range, replacement: text) else { return false }
            command["generation"] = .number(Double(generation))
            let accepted = parent.edit(command)
            if accepted { expectedSelection = NSRange(location: range.location + text.utf16.count, length: 0) }
            return accepted
        }
        func textViewDidChangeSelection(_ textView: UITextView) {
            if textView.selectedRange.length == 0 && textView.selectedRange.location == textView.text.utf16.count && textView.text.hasSuffix("\n") {
                textView.selectedRange = NSRange(location: max(0, textView.selectedRange.location - 1), length: 0); return
            }
            let selected = textView.selectedRange
            if !applying, (textView as? DocsTextView)?.isComposing != true {
                if selected != expectedSelection && selected != parent.selection {
                    parent.selectionMoved()
                    (textView as? DocsTextView)?.lastInputRule = nil
                }
                expectedSelection = nil
            }
            parent.selection = selected
        }
    }
}
#endif