// Adaptateur vscode.Pseudoterminal : expose une session Arboretum comme un terminal NATIF de VS Code
// (rendu, scrollback, copier/coller, liens gratuits). C'est la pièce maîtresse de l'intégration :
// pas de xterm-in-webview. Le pont WS/décodage vit dans SessionBridge (pur) ; cet adaptateur ne fait
// que relier les events Pseudoterminal ↔ bridge.
import * as vscode from 'vscode';
import type { SessionSummary } from '@arboretum/shared';
import type { ArbWsClient } from '../api/ws-client.js';
import { SessionBridge } from './session-bridge.js';

const ANSI_RESET = '\x1bc'; // RIS : réinitialisation complète du terminal (avant le replay d'un RESYNC)

export class SessionTerminalManager {
  private readonly terminals = new Map<string, vscode.Terminal>();
  private readonly bridges = new Map<string, SessionBridge>();

  constructor(private readonly ws: ArbWsClient) {}

  /** Bridge d'une session si un terminal est ouvert (pour répondre à un dialogue sans ré-attacher). */
  getBridge(sessionId: string): SessionBridge | undefined {
    return this.bridges.get(sessionId);
  }

  /** Ouvre (ou ré-affiche) un terminal natif attaché à la session. */
  open(session: SessionSummary, mode: 'interactive' | 'observer'): void {
    const existing = this.terminals.get(session.id);
    if (existing) {
      existing.show();
      return;
    }

    const writeEmitter = new vscode.EventEmitter<string>();
    const closeEmitter = new vscode.EventEmitter<number | void>();
    let bridge: SessionBridge | null = null;

    const pty: vscode.Pseudoterminal = {
      onDidWrite: writeEmitter.event,
      onDidClose: closeEmitter.event,
      open: (dims) => {
        bridge = new SessionBridge(this.ws, session.id, mode, {
          onText: (text) => writeEmitter.fire(text),
          onReset: () => writeEmitter.fire(ANSI_RESET),
          onDetached: () => {
            writeEmitter.fire('\r\n\x1b[2m[arboretum: session ended]\x1b[0m\r\n');
            closeEmitter.fire();
          },
          onControlChanged: (controlling) => {
            if (!controlling && mode === 'interactive') {
              writeEmitter.fire('\r\n\x1b[33m[arboretum: control lost: now observing]\x1b[0m\r\n');
            }
          },
        });
        this.bridges.set(session.id, bridge);
        bridge.open(dims?.columns ?? 80, dims?.rows ?? 24).catch((err: Error) => {
          writeEmitter.fire(`\r\n\x1b[31m[arboretum: cannot attach: ${err.message}]\x1b[0m\r\n`);
          closeEmitter.fire();
        });
      },
      close: () => {
        bridge?.close();
        this.bridges.delete(session.id);
        this.terminals.delete(session.id);
      },
      handleInput: (data) => {
        if (mode === 'interactive') bridge?.sendStdin(data);
      },
      setDimensions: (dims) => bridge?.resize(dims.columns, dims.rows),
    };

    const name = this.terminalName(session, mode);
    const terminal = vscode.window.createTerminal({ name, pty, iconPath: new vscode.ThemeIcon('comment-discussion') });
    this.terminals.set(session.id, terminal);
    terminal.show();
  }

  private terminalName(session: SessionSummary, mode: 'interactive' | 'observer'): string {
    const base = session.title?.trim() || session.cwd.split('/').pop() || session.command;
    const prefix = mode === 'observer' ? '👁 ' : '';
    return `${prefix}${base}`;
  }

  dispose(): void {
    for (const t of this.terminals.values()) t.dispose();
    this.terminals.clear();
    this.bridges.clear();
  }
}