/** `imprint doctor` — check that the environment can actually run imprint.
 *  Reports pass/fail per prerequisite plus a one-line fix when failed. */

import { spawnSync } from 'node:child_process';
import { existsSync, readFileSync, readdirSync } from 'node:fs';
import { homedir } from 'node:os';
import { join as pathJoin } from 'node:path';
import { findChromium } from './chromium.ts';
import { defaultHermesConfigPath } from './install.ts';
import { getProviderStatuses } from './llm.ts';
import { checkForUpdate } from './update.ts';
import { VERSION } from './version.ts';

export interface CheckResult {
  name: string;
  ok: boolean;
  detail: string;
  fix?: string;
}

export async function doctor(): Promise<CheckResult[]> {
  return [
    checkBun(),
    await checkLatestVersion(),
    checkChromium(),
    checkPlaywrightChromium(),
    checkVirtualDisplay(),
    checkLLMProvider(),
    checkPushOptional(),
    checkClaudeCode(),
    checkHermes(),
    checkOpenClaw(),
  ];
}

async function checkLatestVersion(): Promise<CheckResult> {
  const result = await checkForUpdate();
  if (!result) {
    return { name: 'Latest version', ok: true, detail: `v${VERSION} (could not reach registry)` };
  }
  if (!result.updateAvailable) {
    return { name: 'Latest version', ok: true, detail: `v${VERSION} (up to date)` };
  }
  return {
    name: 'Latest version',
    ok: true,
    detail: `v${result.current} → v${result.latest} available`,
    fix: 'run: imprint update',
  };
}

function checkBun(): CheckResult {
  const v = process.versions.bun;
  if (!v) {
    return {
      name: 'Bun runtime',
      ok: false,
      detail: 'not detected (process.versions.bun is undefined)',
      fix: 'install Bun ≥ 1.3 from https://bun.sh',
    };
  }
  return { name: 'Bun runtime', ok: true, detail: `v${v}` };
}

function checkChromium(): CheckResult {
  try {
    const path = findChromium();
    return { name: 'Chromium binary', ok: true, detail: path };
  } catch (err) {
    return {
      name: 'Chromium binary',
      ok: false,
      detail: err instanceof Error ? (err.message.split('\n')[0] ?? '') : String(err),
      fix: 'run: bunx playwright install chromium',
    };
  }
}

function checkPlaywrightChromium(): CheckResult {
  // Playwright's bundled "Chrome for Testing" lives under ms-playwright/.
  // findChromium() prefers it, so this is mostly a duplicate signal — but
  // useful as a separate line so users see whether the Playwright path
  // specifically is set up (matters for stealth-fetch + playbook backends).
  const cacheRoots = [
    process.env.PLAYWRIGHT_BROWSERS_PATH,
    process.env.HERMES_HOME
      ? pathJoin(process.env.HERMES_HOME, '.cache', 'ms-playwright')
      : undefined,
    pathJoin(homedir(), 'Library/Caches/ms-playwright'),
    pathJoin(homedir(), '.cache/ms-playwright'),
  ].filter((root): root is string => Boolean(root));
  for (const root of cacheRoots) {
    if (!existsSync(root)) continue;
    try {
      const dirs = readdirSync(root).filter((d) => /^chromium-\d+$/.test(d));
      if (dirs.length > 0) {
        return {
          name: 'Playwright Chromium',
          ok: true,
          detail: `${dirs.length} install(s) at ${root}`,
        };
      }
    } catch {
      // ignore
    }
  }
  return {
    name: 'Playwright Chromium',
    ok: false,
    detail:
      'no chromium-* install under PLAYWRIGHT_BROWSERS_PATH, $HERMES_HOME/.cache/ms-playwright, ~/Library/Caches/ms-playwright, or ~/.cache/ms-playwright',
    fix: 'run: bunx playwright install chromium  (needed for stealth-fetch + playbook)',
  };
}

function hasXvfbBinary(): boolean {
  try {
    return spawnSync('sh', ['-c', 'command -v Xvfb'], { stdio: 'ignore' }).status === 0;
  } catch {
    return false;
  }
}

/** The trusted-browser replay (playbook rung's cdp-browser transport) runs Chrome
 *  HEADLESS by default and needs NO display — the `HeadlessChrome` UA token is
 *  stripped so anti-bot services don't edge-block it. A display only matters as a
 *  fallback on a GPU-less Linux host, where headless WebGL reports SwiftShader and
 *  the replay must run HEADED under Xvfb (launchChromium auto-starts it when a
 *  headed launch finds no `$DISPLAY`). macOS/Windows need nothing. Advisory only. */
function checkVirtualDisplay(): CheckResult {
  const name = 'Display (headed replay)';
  if (process.platform !== 'linux') {
    return { name, ok: true, detail: `${process.platform}: native window server (no Xvfb needed)` };
  }
  const display = process.env.DISPLAY;
  if (display) return { name, ok: true, detail: `$DISPLAY=${display}` };
  if (hasXvfbBinary()) {
    return {
      name,
      ok: true,
      detail: 'no $DISPLAY; Xvfb present — headed-replay fallback available for GPU-less hosts',
    };
  }
  return {
    name,
    ok: true, // advisory — default replay is headless; Xvfb is only a GPU-less fallback
    detail:
      'Linux, no $DISPLAY and no Xvfb — default replay is headless (fine); install Xvfb only if a GPU-less host gets bot-flagged',
    fix: 'GPU-less host bot-flagged? install the headed-replay fallback: apt-get install xvfb (or export DISPLAY=:0)',
  };
}

function checkLLMProvider(): CheckResult {
  const statuses = getProviderStatuses();
  const detected = statuses.filter((s) => s.detected);
  const teachCompatible = detected.filter((s) => s.availableForTeach);

  if (teachCompatible.length > 0) {
    const names = detected
      .map((s) => `${s.name}${s.availableForTeach ? '' : ' (not teach-compatible)'}`)
      .join(', ');
    return { name: 'LLM provider', ok: true, detail: `detected: ${names}` };
  }

  if (detected.length > 0) {
    return {
      name: 'LLM provider',
      ok: false,
      detail: `detected: ${detected.map((s) => s.name).join(', ')}; none are compatible with teach compile`,
      fix: 'install Claude Code / Codex CLI, or set ANTHROPIC_API_KEY',
    };
  }

  return {
    name: 'LLM provider',
    ok: false,
    detail: 'no provider detected',
    fix: 'install Claude Code / Codex / Cursor CLI, or set ANTHROPIC_API_KEY',
  };
}

function checkPushOptional(): CheckResult {
  const pushover = !!(process.env.PUSHOVER_TOKEN && process.env.PUSHOVER_USER);
  const ntfy = !!process.env.NTFY_URL;
  if (pushover || ntfy) {
    const which = [pushover && 'Pushover', ntfy && 'ntfy'].filter(Boolean).join(' + ');
    return { name: 'Push notifications', ok: true, detail: which };
  }
  return {
    name: 'Push notifications',
    ok: true, // optional — not a failure
    detail: 'none configured (cron will only push to stderr)',
    fix: 'set PUSHOVER_TOKEN+PUSHOVER_USER or NTFY_URL — see docs/notifications.md',
  };
}

function checkClaudeCode(): CheckResult {
  // Look for ~/.claude/settings.json
  const configPath = pathJoin(homedir(), '.claude', 'settings.json');
  if (!existsSync(configPath)) {
    return {
      name: 'Claude Code',
      ok: true,
      detail: 'not detected',
      fix: 'install Claude Code, then run `imprint teach <site>` to connect',
    };
  }
  // Check if any imprint-* MCP servers are registered
  try {
    const config = JSON.parse(readFileSync(configPath, 'utf8'));
    const servers = config?.mcpServers ?? {};
    const imprintServers = Object.keys(servers).filter((k) => k.startsWith('imprint-'));
    if (imprintServers.length > 0) {
      return {
        name: 'Claude Code',
        ok: true,
        detail: `${imprintServers.length} imprint tool(s): ${imprintServers.join(', ')}`,
      };
    }
    return {
      name: 'Claude Code',
      ok: true,
      detail: 'installed, no imprint tools registered',
      fix: 'run `imprint teach <site>` to record a workflow and connect it',
    };
  } catch {
    return {
      name: 'Claude Code',
      ok: true,
      detail: 'installed (could not parse settings)',
    };
  }
}

function checkHermes(): CheckResult {
  const configPath = defaultHermesConfigPath();
  if (!existsSync(configPath)) {
    return {
      name: 'Hermes Agent',
      ok: true,
      detail: 'not detected',
    };
  }
  return {
    name: 'Hermes Agent',
    ok: true,
    detail: `config at ${configPath}`,
    fix: 'run `imprint teach <site>` and select Hermes to connect',
  };
}

function checkOpenClaw(): CheckResult {
  const configPath = pathJoin(homedir(), '.openclaw', 'openclaw.json');
  if (!existsSync(configPath)) {
    return {
      name: 'OpenClaw',
      ok: true,
      detail: 'not detected',
    };
  }
  return {
    name: 'OpenClaw',
    ok: true,
    detail: `config at ${configPath}`,
    fix: 'run `imprint teach <site>` and select OpenClaw to connect',
  };
}

export function reportDoctor(checks: CheckResult[]): { ok: boolean; lines: string[] } {
  const lines: string[] = [`imprint v${VERSION} doctor`, ''];
  let allOk = true;
  for (const c of checks) {
    const mark = c.ok ? '✓' : '✗';
    lines.push(`  ${mark} ${c.name.padEnd(22)} ${c.detail}`);
    if (!c.ok) {
      allOk = false;
      if (c.fix) lines.push(`      → ${c.fix}`);
    } else if (c.fix) {
      // Optional check that's not configured; advise but don't fail.
      lines.push(`      hint: ${c.fix}`);
    }
  }
  lines.push('');
  lines.push(allOk ? 'All required checks passed.' : 'Some required checks failed — fix above.');
  return { ok: allOk, lines };
}