#!/usr/bin/env node
/**
 * Text-path check against a running backend and chat engine.
 * Usage: node scripts/e2e-chat.mjs --base http://127.0.0.1:3000 --link TOKEN --token SESSION
 * The link must already exist for a completed book. This script does not upload a PDF.
 */
const questions = [
  { kind: 'structural', text: 'How is this book organized?' },
  { kind: 'summary', text: 'Summarize the book in a few sentences.' },
  { kind: 'chapter', text: 'What happens in the first chapter?' },
  { kind: 'factual', text: 'Name one specific fact from the book and cite the page.' },
  { kind: 'unanswerable', text: 'What is the narrator\'s phone number?' },
];

function arg(name) {
  const index = process.argv.indexOf(name);
  return index === -1 ? '' : process.argv[index + 1];
}

async function readSse(response) {
  const reader = response.body.getReader();
  const decoder = new TextDecoder();
  let buffer = '';
  const events = [];
  while (true) {
    const next = await reader.read();
    if (next.done) break;
    buffer += decoder.decode(next.value, { stream: true });
    const parts = buffer.split('\n\n');
    buffer = parts.pop() || '';
    for (const part of parts) {
      const line = part.split('\n').find((item) => item.startsWith('data:'));
      if (line) events.push(JSON.parse(line.slice(5).trim()));
    }
  }
  return events;
}

const base = arg('--base') || 'http://127.0.0.1:3000';
const link = arg('--link');
if (!link) {
  process.stderr.write('Pass --link for an existing public link token.\n');
  process.exitCode = 1;
} else {
  const created = await fetch(`${base}/api/public/${link}/session`, { method: 'POST' });
  const session = await created.json();
  if (!created.ok) {
    process.stderr.write(`${session.error || created.status}\n`);
    process.exitCode = 1;
  } else {
    for (const question of questions) {
      const response = await fetch(`${base}/api/public/sessions/${session.sessionId}/messages`, {
        method: 'POST',
        headers: {
          Authorization: `Bearer ${session.sessionToken}`,
          'Content-Type': 'application/json',
        },
        body: JSON.stringify({ text: question.text }),
      });
      const events = await readSse(response);
      const finalEvent = events.find((event) => event.type === 'final');
      const text = finalEvent ? finalEvent.text : '';
      const citations = (finalEvent && finalEvent.citations) || [];
      process.stdout.write(`${question.kind}: ${text.slice(0, 180).replace(/\n/g, ' ')}\n`);
      if (question.kind === 'factual' && citations.length === 0) {
        process.stderr.write('factual answer had no citation\n');
        process.exitCode = 1;
      }
      if (!text) {
        process.stderr.write(`${question.kind} answer was empty\n`);
        process.exitCode = 1;
      }
    }
    await fetch(`${base}/api/public/sessions/${session.sessionId}/end`, {
      method: 'POST',
      headers: { Authorization: `Bearer ${session.sessionToken}` },
    });
  }
}