import AppKit

final class Document: NSDocument, NSTextViewDelegate {
    private var text = ""
    private weak var textView: NSTextView?
    private(set) var workspace: WorkspaceController?
    // Carries "the user picked Sync Now" intent across the save that a dirty
    // or untitled document needs before it can sync.
    private var pendingManualSync = false
    // Lets a newer sync's status win over a slower, older one's completion.
    private var syncGeneration = 0

    override class var autosavesInPlace: Bool { false }

    // MARK: - Window

    override func makeWindowControllers() {
        let scrollView = NSTextView.scrollableTextView()
        guard let tv = scrollView.documentView as? NSTextView else { return }
        configure(textView: tv)
        tv.string = text
        textView = tv

        let window = NSWindow(
            contentRect: NSRect(x: 0, y: 0, width: 900, height: 620),
            styleMask: [.titled, .closable, .miniaturizable, .resizable],
            backing: .buffered,
            defer: false
        )
        window.minSize = NSSize(width: 480, height: 320)
        window.center()

        let workspace = WorkspaceController(document: self, editorScrollView: scrollView, textView: tv)
        self.workspace = workspace
        window.contentView = workspace.containerView
        workspace.installToolbar(on: window)

        let controller = NSWindowController(window: window)
        controller.shouldCascadeWindows = true
        addWindowController(controller)
        loadBoardSidecar()
        window.makeFirstResponder(tv)
    }

    private func configure(textView tv: NSTextView) {
        TextViewConfig.harden(tv)
        tv.usesFindBar = true
        tv.isIncrementalSearchingEnabled = true
        tv.font = AppSettings.editorFont
        tv.textContainerInset = NSSize(width: 8, height: 10)
        tv.delegate = self
    }

    // Route the text view's undo stack through the document so the
    // dirty dot and change count stay accurate automatically.
    func undoManager(for view: NSTextView) -> UndoManager? {
        undoManager
    }

    // MARK: - Reading / writing

    override func data(ofType typeName: String) throws -> Data {
        if let tv = textView {
            text = tv.string
        }
        guard let data = text.data(using: .utf8) else {
            throw NSError(domain: NSCocoaErrorDomain,
                          code: NSFileWriteInapplicableStringEncodingError,
                          userInfo: [NSLocalizedDescriptionKey: "Couldn't encode the text as UTF-8."])
        }
        return data
    }

    override func read(from data: Data, ofType typeName: String) throws {
        if let utf8 = String(data: data, encoding: .utf8) {
            text = utf8
        } else {
            var converted: NSString?
            var lossy: ObjCBool = false
            let encoding = NSString.stringEncoding(for: data,
                                                   encodingOptions: nil,
                                                   convertedString: &converted,
                                                   usedLossyConversion: &lossy)
            // Refuse lossy conversions: saving would silently destroy bytes.
            guard encoding != 0, let converted, !lossy.boolValue else {
                throw NSError(domain: NSCocoaErrorDomain,
                              code: NSFileReadInapplicableStringEncodingError,
                              userInfo: [NSLocalizedDescriptionKey: "Couldn't determine the file's text encoding."])
            }
            text = converted as String
        }
        textView?.string = text
        workspace?.refreshTextMetrics()  // keep the status bar counts current on Revert
    }

    // MARK: - Save hook → sync

    override func save(to url: URL,
                       ofType typeName: String,
                       for saveOperation: NSDocument.SaveOperationType,
                       completionHandler: @escaping (Error?) -> Void) {
        textView?.breakUndoCoalescing()
        super.save(to: url, ofType: typeName, for: saveOperation) { [weak self] error in
            completionHandler(error)
            guard let self else { return }
            let manual = self.pendingManualSync
            self.pendingManualSync = false
            guard error == nil,
                  saveOperation == .saveOperation || saveOperation == .saveAsOperation else { return }
            self.saveBoardSidecar()
            self.syncAfterSave(url: url, manual: manual)
            self.autoIngestAfterSave()
        }
    }

    @objc func syncNow(_ sender: Any?) {
        if let url = fileURL, !isDocumentEdited {
            syncAfterSave(url: url, manual: true)
            return
        }
        // Dirty or untitled: save first; the save hook picks up the manual flag.
        pendingManualSync = true
        save(withDelegate: self,
             didSave: #selector(document(_:didSave:contextInfo:)),
             contextInfo: nil)
    }

    // Clears the manual flag when the user cancels the Save panel (the save
    // override never runs in that case, so the flag would leak into the next save).
    @objc private func document(_ document: NSDocument, didSave: Bool, contextInfo: UnsafeMutableRawPointer?) {
        if !didSave { pendingManualSync = false }
    }

    private func syncAfterSave(url: URL, manual: Bool) {
        guard SyncSettings.enabled || manual else {
            syncStatus = ""  // sync is off — don't leave a stale "Synced ✓"
            refreshSubtitle()
            return
        }
        guard SyncSettings.isConfigured else {
            if manual {
                presentSyncError("No remote configured. Set one in TextPlus → Settings…")
            } else {
                syncStatus = "Sync is on, but no remote is configured — see Settings"
                refreshSubtitle()
            }
            return
        }
        let remoteHost = SyncSettings.remote
        syncGeneration += 1
        let generation = syncGeneration
        syncStatus = "Syncing to \(remoteHost)…"
        refreshSubtitle()
        SyncEngine.upload(fileURL: url) { [weak self] result in
            guard let self, generation == self.syncGeneration else { return }
            switch result {
            case .success:
                let time = Date().formatted(date: .omitted, time: .shortened)
                self.syncStatus = "Synced to \(remoteHost) ✓ \(time)"
            case .failure(let error):
                let firstLine = error.message.split(separator: "\n").first.map(String.init) ?? "unknown error"
                self.syncStatus = "Sync failed — \(firstLine)"
                NSApp.requestUserAttention(.informationalRequest)
                if manual { self.presentSyncError(error.message) }
            }
            self.refreshSubtitle()
        }
    }

    private var syncStatus = ""
    private var dbStatus = ""
    private var dbGeneration = 0
    private var ingestInFlight = false

    private func refreshSubtitle() {
        let subtitle = [syncStatus, dbStatus].filter { !$0.isEmpty }.joined(separator: "   ·   ")
        windowControllers.first?.window?.subtitle = subtitle
    }

    private func presentSyncError(_ message: String) {
        let alert = NSAlert()
        alert.messageText = "Sync Failed"
        alert.informativeText = message
        alert.alertStyle = .warning
        if let window = windowControllers.first?.window {
            alert.beginSheetModal(for: window)
        } else {
            alert.runModal()
        }
    }

    // MARK: - HTML parsing tools

    private var currentText: String {
        textView?.string ?? text
    }

    private static let lastSelectorKey = "lastExtractSelector"

    @objc func listSelectors(_ sender: Any?) {
        let data = HTMLScanner.summarize(html: currentText)
        Document.openResults(HTMLScanner.formatSummary(data, sourceName: displayName ?? "document"))
    }

    @objc func extractListings(_ sender: Any?) {
        let page = PageDetector.detect(in: currentText) ?? DetectedPage(url: nil, html: currentText)
        let profile = ScrapeProfile.matching(url: page.url) ?? ScrapeProfile.discogsMarketplace
        guard let extraction = HTMLScanner.extractRows(html: page.html,
                                                       rowSelector: profile.rowSelector,
                                                       fields: profile.fields),
              !extraction.rows.isEmpty else {
            presentSimpleAlert(title: "No Listings Found",
                               message: "No \(profile.rowSelector) rows in this document. This works on Discogs marketplace pages (sell/list or a seller's profile).")
            return
        }
        var out = extraction.header.joined(separator: "\t") + "\n"
        out += extraction.rows.map { $0.joined(separator: "\t") }.joined(separator: "\n") + "\n"
        Document.openResults(out)
    }

    @objc func sendToPostgres(_ sender: Any?) {
        guard let page = PageDetector.detect(in: currentText) else {
            presentSimpleAlert(title: "Not an HTML Page",
                               message: "Paste inspector HTML — optionally with the page URL as the first line — and try again.")
            return
        }
        runIngest(page: page, manual: true)
    }

    private func autoIngestAfterSave() {
        guard PGSettings.autoIngest, let page = PageDetector.detect(in: currentText) else {
            dbStatus = ""
            refreshSubtitle()
            return
        }
        runIngest(page: page, manual: false)
    }

    private func runIngest(page: DetectedPage, manual: Bool) {
        // One ingest per document at a time: a second overlapping ingest of the
        // same page would bypass the content-hash dedup (its check runs before
        // the first commits) and double-insert audit rows.
        if ingestInFlight {
            if manual {
                presentSimpleAlert(title: "Ingest In Progress",
                                   message: "This document is already being sent to Postgres. Try again once it finishes.")
            }
            return
        }
        ingestInFlight = true
        dbGeneration += 1
        let generation = dbGeneration
        dbStatus = "DB: parsing…"
        refreshSubtitle()
        let sourceName = displayName ?? "document"

        func finish(_ status: String, alert: String? = nil) {
            ingestInFlight = false
            guard generation == dbGeneration else { return }
            dbStatus = status
            refreshSubtitle()
            if let alert { presentSimpleAlert(title: "Postgres Ingest Failed", message: alert) }
        }

        DispatchQueue.global(qos: .userInitiated).async { [weak self] in
            let summary = HTMLScanner.summarize(html: page.html)
            let profile = ScrapeProfile.matching(url: page.url)
            var header: [String] = []
            var rows: [[String]] = []
            if let profile,
               let extraction = HTMLScanner.extractRows(html: page.html,
                                                        rowSelector: profile.rowSelector,
                                                        fields: profile.fields) {
                header = extraction.header
                rows = extraction.rows
            }
            let ingest = PostgresStore.PageIngest(
                url: page.url,
                sourceName: sourceName,
                contentHash: PostgresStore.sha256(page.html),
                elementCount: summary.elementCount,
                selectors: summary.entries,
                profileName: rows.isEmpty ? nil : profile?.name,
                header: header,
                rows: rows
            )
            DispatchQueue.main.async {
                guard let self else { return }
                guard generation == self.dbGeneration else { self.ingestInFlight = false; return }
                self.dbStatus = "DB: ingesting…"
                self.refreshSubtitle()
                // `finish` already holds self for the duration of the ingest.
                PostgresStore.ingest(ingest, force: manual) { result in
                    switch result {
                    case .success(let report):
                        if report.skippedDuplicate {
                            finish("DB: unchanged")
                        } else {
                            var bits = ["\(report.selectorCount) selectors"]
                            if report.snapshotCount > 0 { bits.append("\(report.snapshotCount) listings upserted") }
                            else if report.rowCount > 0 { bits.append("\(report.rowCount) rows") }
                            if report.skippedRows > 0 { bits.append("\(report.skippedRows) skipped") }
                            finish("DB ✓ page #\(report.pageId): " + bits.joined(separator: ", "))
                        }
                    case .failure(let error):
                        let firstLine = error.message.split(separator: "\n").first.map(String.init) ?? "error"
                        finish("DB failed — \(firstLine)", alert: manual ? error.message : nil)
                    }
                }
            }
        }
    }

    @objc func extractForSelector(_ sender: Any?) {
        let alert = NSAlert()
        alert.messageText = "Extract Text for Selector"
        alert.informativeText = "Pulls the text of every matching element into a new document, one match per line (table cells tab-separated). A trailing @attr adds that attribute as the first column; [attr], [!attr], [attr=v], [attr^=v] filter matches.\n\nExamples: .price   tr.shortcut_navigable   a.item_description_title@href   .item_condition span[!class]"
        let field = NSTextField(frame: NSRect(x: 0, y: 0, width: 380, height: 24))
        field.stringValue = UserDefaults.standard.string(forKey: Document.lastSelectorKey) ?? ""
        field.placeholderString = "tag, .class, #id, or a descendant chain"
        alert.accessoryView = field
        alert.addButton(withTitle: "Extract")
        alert.addButton(withTitle: "Cancel")
        alert.window.initialFirstResponder = field
        // The field editor swallows Return before the default button sees it;
        // wire the field's action to the Extract button so Return submits.
        field.target = alert.buttons[0]
        field.action = #selector(NSButton.performClick(_:))

        let runExtract: () -> Void = { [weak self] in
            guard let self else { return }
            let selector = field.stringValue.trimmingCharacters(in: .whitespaces)
            guard !selector.isEmpty else { return }
            UserDefaults.standard.set(selector, forKey: Document.lastSelectorKey)
            guard let result = HTMLScanner.extractText(html: self.currentText,
                                                       selector: selector,
                                                       sourceName: self.displayName ?? "document") else {
                self.presentSimpleAlert(title: "Bad Selector",
                                        message: "Couldn't parse \"\(selector)\". Use tag, .class, #id, combos like tr.shortcut_navigable, or a space-separated descendant chain.")
                return
            }
            guard result.matchCount > 0 else {
                self.presentSimpleAlert(title: "No Matches",
                                        message: "Nothing matched \"\(selector)\". Run Tools → List Div & Class Selectors to see what's in this page.")
                return
            }
            Document.openResults(result.body)
        }

        if let window = windowControllers.first?.window {
            alert.beginSheetModal(for: window) { response in
                guard response == .alertFirstButtonReturn else { return }
                runExtract()
            }
        } else if alert.runModal() == .alertFirstButtonReturn {
            runExtract()
        }
    }

    private static func openResults(_ content: String) {
        guard let doc = (try? NSDocumentController.shared.openUntitledDocumentAndDisplay(true)) as? Document else { return }
        doc.setContent(content)
    }

    private func setContent(_ s: String) {
        text = s
        textView?.string = s
        workspace?.applyAppearance()  // theme the freshly inserted results
        workspace?.refreshTextMetrics()
        updateChangeCount(.changeDone)
    }

    private func presentSimpleAlert(title: String, message: String) {
        let alert = NSAlert()
        alert.messageText = title
        alert.informativeText = message
        if let window = windowControllers.first?.window {
            alert.beginSheetModal(for: window)
        } else {
            alert.runModal()
        }
    }

    // MARK: - Font size (broadcast to every open window via AppSettings)

    @objc func makeTextBigger(_ sender: Any?) {
        AppSettings.set(AppSettings.fontSizeKey, Double(min(48, AppSettings.fontSize + 1)))
    }

    @objc func makeTextSmaller(_ sender: Any?) {
        AppSettings.set(AppSettings.fontSizeKey, Double(max(8, AppSettings.fontSize - 1)))
    }

    // MARK: - View mode (menu) + appearance toggles

    @objc func showEditorMode(_ sender: Any?) { workspace?.setMode(.editor) }
    @objc func showSplitMode(_ sender: Any?) { workspace?.setMode(.split) }
    @objc func showBoardMode(_ sender: Any?) { workspace?.setMode(.board) }

    @objc func toggleSoftWrap(_ sender: Any?) {
        AppSettings.set(AppSettings.softWrapKey, !AppSettings.softWrap)
    }

    @objc func toggleLineNumbers(_ sender: Any?) {
        AppSettings.set(AppSettings.lineNumbersKey, !AppSettings.lineNumbers)
    }

    @objc func cycleTheme(_ sender: Any?) {
        let all = EditorTheme.all
        let idx = all.firstIndex { $0.id == AppSettings.theme.id } ?? 0
        AppSettings.set(AppSettings.themeKey, all[(idx + 1) % all.count].id)
    }

    // MARK: - Markdown markup (selection-aware)

    @objc func markupBold(_ sender: Any?) { withTextView { TextMarkup.wrap($0, prefix: "**", suffix: "**", placeholder: "bold") } }
    @objc func markupItalic(_ sender: Any?) { withTextView { TextMarkup.wrap($0, prefix: "*", suffix: "*", placeholder: "italic") } }
    @objc func markupCode(_ sender: Any?) { withTextView { TextMarkup.wrap($0, prefix: "`", suffix: "`", placeholder: "code") } }
    @objc func markupStrikethrough(_ sender: Any?) { withTextView { TextMarkup.wrap($0, prefix: "~~", suffix: "~~", placeholder: "strike") } }
    @objc func markupHeading(_ sender: Any?) { withTextView { TextMarkup.linePrefix($0, prefix: "# ") } }
    @objc func markupList(_ sender: Any?) { withTextView { TextMarkup.linePrefix($0, prefix: "- ") } }
    @objc func markupQuote(_ sender: Any?) { withTextView { TextMarkup.linePrefix($0, prefix: "> ") } }
    @objc func markupLink(_ sender: Any?) { withTextView { TextMarkup.wrap($0, prefix: "[", suffix: "](https://)", placeholder: "label") } }

    private func withTextView(_ body: (NSTextView) -> Void) {
        guard let textView else { return }
        body(textView)
    }

    // MARK: - Board sidecar (foo.txt.board/) + image import

    /// Bundle directory next to the document: foo.txt → foo.txt.board/
    private func boardSidecarDir() -> URL? {
        fileURL?.appendingPathExtension("board")
    }

    private var legacyCanvasURL: URL? {
        fileURL?.appendingPathExtension("canvas.json")
    }

    /// Build the board model: from the sidecar if present, else migrate a legacy
    /// canvas sidecar's shapes, else a fresh default board. Never throws.
    func loadBoardSidecar() {
        guard let board = workspace?.boardContainer.boardView else { return }
        var doc: BoardDoc?
        if let dir = boardSidecarDir(),
           let data = try? Data(contentsOf: dir.appendingPathComponent("board.json")),
           let decoded = try? JSONDecoder().decode(BoardDoc.self, from: data) {
            doc = decoded
        } else if let legacy = legacyCanvasURL,
                  let data = try? Data(contentsOf: legacy),
                  let canvasDoc = try? JSONDecoder().decode(DrawCanvasView.CanvasDoc.self, from: data) {
            // One-way migration of the old paint canvas into the board shapes layer.
            var fresh = BoardDoc.makeDefault(worldSize: BoardView.worldSize)
            fresh.shapes = canvasDoc
            doc = fresh
        }
        let finalDoc = doc ?? BoardDoc.makeDefault(worldSize: BoardView.worldSize)
        board.load(doc: finalDoc)
        workspace?.boardContainer.refreshPageControls()
        workspace?.bindInitialEditorPage()   // main card owns the document text view
        // Load image assets by card id.
        if let dir = boardSidecarDir() {
            for card in finalDoc.cards where card.kind == .image {
                let name = card.imageFile ?? "img-\(card.id).png"
                if let img = NSImage(contentsOf: dir.appendingPathComponent(name)) {
                    board.setImage(img, forCardID: card.id)
                }
            }
        }
    }

    private func saveBoardSidecar() {
        guard let board = workspace?.boardContainer.boardView, let dir = boardSidecarDir() else { return }
        let doc = board.snapshotDoc
        let fm = FileManager.default
        // Don't create a sidecar for an untouched plaintext doc, but ALWAYS keep
        // an existing one current — otherwise clearing a board back to empty
        // would leave a stale board.json that resurrects the deleted objects.
        let used = doc.cards.count > 1 || !doc.shapes.elements.isEmpty
            || !(board.mainCardView?.textView?.string.isEmpty ?? true)
        guard used || fm.fileExists(atPath: dir.path) else { return }
        try? fm.createDirectory(at: dir, withIntermediateDirectories: true)

        if let data = try? JSONEncoder.boardEncoder.encode(doc) {
            let tmp = dir.appendingPathComponent("board.json.tmp")
            let dest = dir.appendingPathComponent("board.json")
            if (try? data.write(to: tmp)) != nil {
                _ = try? fm.replaceItemAt(dest, withItemAt: tmp)
            }
        }
        // Write image assets; collect kept filenames for orphan GC.
        var kept = Set(["board.json", "preview.png"])
        for card in doc.cards where card.kind == .image {
            let name = card.imageFile ?? "img-\(card.id).png"
            kept.insert(name)
            if let img = board.image(forCardID: card.id),
               let png = pngData(from: img) {
                try? png.write(to: dir.appendingPathComponent(name), options: .atomic)
            }
        }
        if let preview = workspace?.boardContainer.boardPNG() {
            try? preview.write(to: dir.appendingPathComponent("preview.png"), options: .atomic)
        }
        // GC orphaned image files for this document's bundle only.
        if let names = try? fm.contentsOfDirectory(atPath: dir.path) {
            for n in names where n.hasPrefix("img-") && !kept.contains(n) {
                try? fm.removeItem(at: dir.appendingPathComponent(n))
            }
        }
    }

    /// Import an image file as a new board card (re-encoded to PNG on save).
    func importImageToBoard(url: URL, at center: NSPoint) {
        guard let image = NSImage(contentsOf: url), let board = workspace?.boardContainer.boardView else { return }
        board.addImageCard(image, at: center)
    }

    func importImageToBoard(_ image: NSImage, at center: NSPoint) {
        workspace?.boardContainer.boardView.addImageCard(image, at: center)
    }

    private func pngData(from image: NSImage) -> Data? {
        guard let tiff = image.tiffRepresentation, let rep = NSBitmapImageRep(data: tiff) else { return nil }
        return rep.representation(using: .png, properties: [:])
    }

    /// Write the PNG to a temp file and reuse the scp sync engine to push it to
    /// the configured tailnet Mac — same destination as text files.
    func sendSketchToTailnet(pngData: Data) {
        guard SyncSettings.isConfigured else {
            workspace?.setStatus("Set a tailnet remote in Settings first")
            return
        }
        let base = (displayName ?? "sketch").replacingOccurrences(of: " ", with: "_")
        let tmp = FileManager.default.temporaryDirectory
            .appendingPathComponent("\(base)-sketch.png")
        do {
            try pngData.write(to: tmp)
        } catch {
            workspace?.setStatus("Couldn't stage PNG: \(error.localizedDescription)")
            return
        }
        workspace?.setStatus("Sending sketch to \(SyncSettings.remote)…")
        SyncEngine.upload(fileURL: tmp) { [weak self] result in
            switch result {
            case .success:
                self?.workspace?.setStatus("Sketch sent to \(SyncSettings.remote) ✓")
            case .failure(let error):
                let line = error.message.split(separator: "\n").first.map(String.init) ?? "failed"
                self?.workspace?.setStatus("Sketch sync failed — \(line)")
            }
            try? FileManager.default.removeItem(at: tmp)
        }
    }
}