import path from 'node:path';
import * as vscode from 'vscode';
import { isMainFile, isRegistryFile, parseRegistry } from '../model/format';
import { RegistryPanel, registryPanelFromIndex, registryPanelStandalone } from '../model/panel';
import { ModelService } from '../model/service';
import { readText } from '../util/files';
import { log } from '../util/log';
import { handleWebviewMessage, WebviewMessage } from '../webview/messages';
import { makeNonce, registryPage } from '../webview/page';
import { DIAGRAM_EDITOR_VIEW_TYPE, REGISTRY_VIEW_TYPE } from './viewTypes';

export { REGISTRY_VIEW_TYPE };

class RegistryDocument implements vscode.CustomDocument {
  constructor(readonly uri: vscode.Uri) {}
  dispose(): void {}
}

class RegistryView implements vscode.Disposable {
  private seq = 0;
  private timer: NodeJS.Timeout | undefined;
  private last: string | undefined;
  root: vscode.Uri | undefined;
  private readonly disposables: vscode.Disposable[] = [];

  constructor(
    private readonly models: ModelService,
    readonly panel: vscode.WebviewPanel,
    readonly uri: vscode.Uri,
  ) {
    this.disposables.push(
      panel.webview.onDidReceiveMessage((message: WebviewMessage) => {
        if (message.type === 'openDiagram') return void this.openInModel(message.path, DIAGRAM_EDITOR_VIEW_TYPE);
        if (message.type === 'openRegistry') return void this.openRegistryLine(message.file, message.line);
        void handleWebviewMessage(message, this.uri, this.panel);
      }),
    );
    void this.update();
  }

  private async openInModel(relativePath: string, viewType: string): Promise<void> {
    if (!this.root) return;
    const target = vscode.Uri.joinPath(this.root, ...relativePath.split('/'));
    try {
      await vscode.workspace.fs.stat(target);
    } catch {
      vscode.window.showWarningMessage(`Archify: ${relativePath} does not exist in this model.`);
      return;
    }
    await vscode.commands.executeCommand('vscode.openWith', target, viewType, vscode.ViewColumn.Active);
  }

  private async openRegistryLine(file: string, line?: number): Promise<void> {
    const target = this.root ? vscode.Uri.joinPath(this.root, ...file.split('/')) : this.uri;
    const column = this.panel.viewColumn === vscode.ViewColumn.One ? vscode.ViewColumn.Two : vscode.ViewColumn.One;
    const at = Math.max(line ?? 0, 0);
    await vscode.window.showTextDocument(target, { viewColumn: column, selection: new vscode.Range(at, 0, at, 0) });
  }

  scheduleUpdate(): void {
    clearTimeout(this.timer);
    this.timer = setTimeout(() => void this.update(), 300);
  }

  async update(): Promise<void> {
    clearTimeout(this.timer);
    const seq = ++this.seq;
    let registry: RegistryPanel;
    try {
      this.root = await this.models.rootOf(this.uri);
      if (this.root) {
        const rel = path.relative(this.root.fsPath, this.uri.fsPath).split(path.sep).join('/');
        registry = registryPanelFromIndex(await this.models.index(this.root), rel);
      } else {
        const name = path.basename(this.uri.path);
        registry = registryPanelStandalone(name, parseRegistry(await readText(this.uri), name));
      }
    } catch (error) {
      log().warn(`Registry view failed for ${this.uri.fsPath}: ${error instanceof Error ? error.message : String(error)}`);
      return;
    }
    if (seq !== this.seq) return;
    const fingerprint = JSON.stringify(registry);
    if (fingerprint === this.last) return;
    this.last = fingerprint;
    this.panel.webview.html = registryPage({ cspSource: this.panel.webview.cspSource, nonce: makeNonce() }, registry);
  }

  dispose(): void {
    clearTimeout(this.timer);
    for (const d of this.disposables.splice(0)) d.dispose();
  }
}

export class RegistryViewProvider implements vscode.CustomReadonlyEditorProvider<RegistryDocument>, vscode.Disposable {
  private readonly views = new Set<RegistryView>();
  private active: RegistryView | undefined;
  private readonly disposables: vscode.Disposable[];

  constructor(private readonly models: ModelService) {
    this.disposables = [
      vscode.window.registerCustomEditorProvider(REGISTRY_VIEW_TYPE, this, {
        webviewOptions: { retainContextWhenHidden: true, enableFindWidget: true },
        supportsMultipleEditorsPerDocument: true,
      }),
      // Any change in the model (a diagram starts or stops using an element, a registry edit) refreshes the page.
      models.onDidChangeModel(({ root }) => {
        for (const view of this.views) if (view.root?.toString() === root.toString()) view.scheduleUpdate();
      }),
      vscode.workspace.onDidChangeTextDocument((event) => {
        if (!isRegistryFile(event.document.fileName) && !isMainFile(event.document.fileName)) return;
        // Outside a model the model service stays quiet; refresh the page of the edited file itself.
        for (const view of this.views) if (!view.root && view.uri.toString() === event.document.uri.toString()) view.scheduleUpdate();
      }),
    ];
  }

  /** File shown in the focused registry view, if any. */
  get activeUri(): vscode.Uri | undefined {
    return this.active?.uri;
  }

  openCustomDocument(uri: vscode.Uri): RegistryDocument {
    return new RegistryDocument(uri);
  }

  async resolveCustomEditor(document: RegistryDocument, panel: vscode.WebviewPanel): Promise<void> {
    panel.webview.options = { enableScripts: true };
    const view = new RegistryView(this.models, panel, document.uri);
    this.views.add(view);
    const onViewState = () => {
      if (panel.active) this.active = view;
      else if (this.active === view) this.active = undefined;
      if (panel.active) void vscode.commands.executeCommand('setContext', 'archify.inModel', Boolean(view.root));
    };
    panel.onDidChangeViewState(onViewState);
    onViewState();
    panel.onDidDispose(() => {
      this.views.delete(view);
      if (this.active === view) this.active = undefined;
      view.dispose();
    });
  }

  dispose(): void {
    for (const view of this.views) view.dispose();
    this.views.clear();
    for (const d of this.disposables.splice(0)) d.dispose();
  }
}