import fs from 'node:fs/promises';
import path from 'node:path';
import * as vscode from 'vscode';
import { diagramBaseName, isArchifyFile, isArchifyHtml, isDiagramFileName, readDiagramSource } from './detect';
import { DiagnosticsController } from './diagnostics';
import { HTML_VIEW_TYPE, HtmlViewerProvider } from './htmlViewer';
import { DIAGRAM_EDITOR_VIEW_TYPE, PreviewManager } from './preview';
import { isEvidenceError, renderDiagram, renderToFile } from './renderer';
import { clearGitRootCache, evidenceMode, log, readText, runtimeFor } from './runtime';

const JSON_LANGUAGES = new Set(['json', 'jsonc']);

function isHtmlUri(uri: vscode.Uri): boolean {
  return /\.html?$/i.test(uri.path);
}

export function activate(context: vscode.ExtensionContext): void {
  const previews = new PreviewManager(context);
  const htmlViewer = new HtmlViewerProvider();
  context.subscriptions.push(previews, htmlViewer, new DiagnosticsController(context), log());

  /** The file a command applies to: explicit argument, focused preview or viewer, then the text editor. */
  function targetUri(arg?: unknown): vscode.Uri | undefined {
    if (arg instanceof vscode.Uri) return arg;
    return previews.activePreview?.uri ?? htmlViewer.activeUri ?? vscode.window.activeTextEditor?.document.uri;
  }

  function sourceUri(arg?: unknown): vscode.Uri | undefined {
    const uri = targetUri(arg);
    if (!uri) vscode.window.showWarningMessage('Archify: open a diagram JSON source first.');
    return uri;
  }

  // Context keys for editor title buttons and keybindings.
  let contextTimer: NodeJS.Timeout | undefined;
  const updateContext = () => {
    const doc = vscode.window.activeTextEditor?.document;
    const diagram = Boolean(
      doc &&
        (isArchifyFile(doc.fileName) ||
          (JSON_LANGUAGES.has(doc.languageId) && (isDiagramFileName(doc.fileName) || readDiagramSource(doc.getText(), doc.fileName)))),
    );
    const html = Boolean(doc && doc.languageId === 'html' && isArchifyHtml(doc.getText()));
    void vscode.commands.executeCommand('setContext', 'archify.isDiagramSource', diagram);
    void vscode.commands.executeCommand('setContext', 'archify.isArchifyHtml', html);
  };
  context.subscriptions.push(
    vscode.window.onDidChangeActiveTextEditor(updateContext),
    vscode.workspace.onDidChangeTextDocument((event) => {
      if (event.document !== vscode.window.activeTextEditor?.document) return;
      clearTimeout(contextTimer);
      contextTimer = setTimeout(updateContext, 300);
    }),
    vscode.workspace.onDidChangeConfiguration((event) => {
      if (event.affectsConfiguration('archify.repoRoot')) clearGitRootCache();
    }),
    { dispose: () => clearTimeout(contextTimer) },
  );
  updateContext();

  const openHtmlViewer = (uri: vscode.Uri, viewColumn?: vscode.ViewColumn) =>
    vscode.commands.executeCommand('vscode.openWith', uri, HTML_VIEW_TYPE, viewColumn);

  context.subscriptions.push(
    vscode.commands.registerCommand('archify.showPreview', (arg?: unknown) => {
      const uri = sourceUri(arg);
      if (!uri) return;
      if (isHtmlUri(uri)) return openHtmlViewer(uri);
      if (isArchifyFile(uri.path)) return vscode.commands.executeCommand('vscode.openWith', uri, DIAGRAM_EDITOR_VIEW_TYPE);
      previews.show(uri, vscode.window.activeTextEditor?.viewColumn ?? vscode.ViewColumn.Active);
    }),

    vscode.commands.registerCommand('archify.showPreviewToSide', (arg?: unknown) => {
      const uri = sourceUri(arg);
      if (!uri) return;
      if (isHtmlUri(uri)) return openHtmlViewer(uri, vscode.ViewColumn.Beside);
      if (isArchifyFile(uri.path)) {
        return vscode.commands.executeCommand('vscode.openWith', uri, DIAGRAM_EDITOR_VIEW_TYPE, {
          viewColumn: vscode.ViewColumn.Beside,
          preserveFocus: true,
        });
      }
      previews.show(uri, vscode.ViewColumn.Beside, true);
    }),

    vscode.commands.registerCommand('archify.openHtmlViewer', (arg?: unknown) => {
      const uri = sourceUri(arg);
      if (uri) return openHtmlViewer(uri);
    }),

    vscode.commands.registerCommand('archify.refreshPreview', () => previews.activePreview?.update(true)),

    vscode.commands.registerCommand('archify.showSource', async () => {
      const preview = previews.activePreview;
      if (preview?.isEditor) {
        // The diagram is the editor; open the YAML text beside it.
        await vscode.commands.executeCommand('vscode.openWith', preview.uri, 'default', vscode.ViewColumn.Beside);
        return;
      }
      if (preview) {
        const column = preview.panel.viewColumn === vscode.ViewColumn.One ? vscode.ViewColumn.Two : vscode.ViewColumn.One;
        await vscode.window.showTextDocument(preview.uri, { viewColumn: column });
        return;
      }
      const html = htmlViewer.activeUri;
      if (html) await vscode.commands.executeCommand('vscode.openWith', html, 'default');
    }),

    vscode.commands.registerCommand('archify.renderToHtml', async (arg?: unknown) => {
      const uri = sourceUri(arg);
      if (!uri) return;
      const text = await readText(uri);
      const source = readDiagramSource(text, uri.path);
      if (!source) {
        vscode.window.showWarningMessage(`Archify: ${path.basename(uri.path)} has no "diagram_type" (architecture, workflow, sequence, dataflow or lifecycle).`);
        return;
      }
      const meta = (source.diagram.meta ?? {}) as { output?: unknown };
      const authored = typeof meta.output === 'string' && !/[\\/]/.test(meta.output) ? meta.output : undefined;
      const fileName = authored ?? `${diagramBaseName(uri.path)}.html`;
      const defaultUri = uri.scheme === 'file' ? vscode.Uri.joinPath(uri, '..', fileName) : undefined;
      const target = await vscode.window.showSaveDialog({
        defaultUri,
        filters: { HTML: ['html'] },
        saveLabel: 'Render',
      });
      if (!target) return;

      const runtime = await runtimeFor(context, uri);
      let result = await vscode.window.withProgress(
        { location: vscode.ProgressLocation.Notification, title: 'Archify: rendering…' },
        () => renderToFile(runtime, source, target.fsPath),
      );
      if (!result.ok && isEvidenceError(result.error)) {
        const choice = await vscode.window.showWarningMessage(
          'Archify could not verify the diagram\'s source evidence against a local checkout.',
          { modal: true, detail: result.error },
          'Render Without Source Links',
        );
        if (choice) result = await renderToFile(runtime, source, target.fsPath, true);
        else return;
      }
      if (!result.ok) {
        log().error(result.error ?? 'render failed');
        vscode.window.showErrorMessage('Archify: render failed.', { modal: true, detail: result.error });
        return;
      }
      const choice = await vscode.window.showInformationMessage(
        `Rendered ${path.basename(target.fsPath)}`,
        'Open in Viewer',
        'Open in Browser',
      );
      if (choice === 'Open in Viewer') await openHtmlViewer(target);
      if (choice === 'Open in Browser') await vscode.env.openExternal(target);
    }),

    vscode.commands.registerCommand('archify.openInBrowser', async (arg?: unknown) => {
      const uri = sourceUri(arg);
      if (!uri) return;
      if (isHtmlUri(uri)) {
        await vscode.env.openExternal(uri);
        return;
      }
      const text = await readText(uri);
      const source = readDiagramSource(text, uri.path);
      if (!source) {
        vscode.window.showWarningMessage(`Archify: ${path.basename(uri.path)} has no "diagram_type" (architecture, workflow, sequence, dataflow or lifecycle).`);
        return;
      }
      const runtime = await runtimeFor(context, uri);
      const result = await vscode.window.withProgress(
        { location: vscode.ProgressLocation.Notification, title: 'Archify: rendering…' },
        () => renderDiagram(runtime, source, evidenceMode(uri)),
      );
      if (!result.ok || !result.html) {
        vscode.window.showErrorMessage('Archify: render failed.', { modal: true, detail: result.error });
        return;
      }
      const dir = path.join(context.globalStorageUri.fsPath, 'browser');
      await fs.mkdir(dir, { recursive: true });
      const file = path.join(dir, `${diagramBaseName(uri.path)}.html`);
      await fs.writeFile(file, result.html, 'utf8');
      await vscode.env.openExternal(vscode.Uri.file(file));
    }),
  );
}

export function deactivate(): void {}