/**
 * Keep clicker/requirements.txt applied, cheaply.
 *
 * Called from start-all.mjs on every boot, and from update-check.mjs when a
 * pull touches requirements.txt. Running `pip install` unconditionally would
 * add seconds to every start and fail outright on a machine whose network is
 * not up yet, so the work is guarded by a hash plus an import probe.
 *
 * Failure is never fatal: the dashboard and the trading loops do not need
 * Python. Only the clicker does.
 */
import { createHash } from 'node:crypto';
import { existsSync, readFileSync, writeFileSync } from 'node:fs';
import { spawnSync } from 'node:child_process';
import path from 'node:path';
import { fileURLToPath } from 'node:url';

const ROOT = path.resolve(path.dirname(fileURLToPath(import.meta.url)), '..');
const REQUIREMENTS = path.join(ROOT, 'clicker', 'requirements.txt');
const HASH_FILE = path.join(ROOT, 'scripts', '.deps-hash');
const PYTHON_CMD_FILE = path.join(ROOT, 'scripts', '.python-cmd');

/** Run `<cmd> <args>`; cmd may carry arguments of its own, e.g. "py -3". */
function run(cmd, args, opts = {}) {
    const parts = cmd.split(/\s+/);
    return spawnSync(parts[0], [...parts.slice(1), ...args], {
        cwd: ROOT,
        encoding: 'utf8',
        shell: process.platform === 'win32',
        ...opts,
    });
}

/** A real interpreter answers with its major version. The Microsoft Store stub
 *  that Windows puts on PATH produces nothing, which is how we tell them apart. */
function isRealPython(cmd) {
    const r = run(cmd, ['-c', 'import sys;print(sys.version_info[0])']);
    return r.status === 0 && (r.stdout ?? '').trim() === '3';
}

export function resolvePython() {
    // setup-windows.bat already did this detection properly, stub check included,
    // and recorded what it found. Prefer that over guessing again.
    if (existsSync(PYTHON_CMD_FILE)) {
        const saved = readFileSync(PYTHON_CMD_FILE, 'utf8').trim();
        if (saved && isRealPython(saved)) return saved;
    }
    for (const candidate of ['py -3', 'python3', 'python']) {
        if (isRealPython(candidate)) return candidate;
    }
    return null;
}

export function ensurePythonDeps({ log = console.log, force = false } = {}) {
    if (!existsSync(REQUIREMENTS)) {
        return { ok: true, action: 'skipped', reason: 'no requirements.txt' };
    }

    const python = resolvePython();
    if (!python) {
        log('[deps] python not found — clicker dependencies skipped (dashboard is unaffected)');
        return { ok: false, action: 'skipped', reason: 'no python' };
    }

    const wanted = createHash('sha256').update(readFileSync(REQUIREMENTS)).digest('hex');
    const recorded = existsSync(HASH_FILE) ? readFileSync(HASH_FILE, 'utf8').trim() : '';
    const importsOk = run(python, ['-c', 'import pyautogui']).status === 0;

    if (!force && wanted === recorded && importsOk) {
        return { ok: true, action: 'up-to-date', python };
    }

    log(`[deps] installing clicker dependencies via "${python}"${importsOk ? '' : ' (pyautogui does not import)'}`);
    const install = run(python, [
        '-m', 'pip', 'install', '--disable-pip-version-check', '--quiet',
        '-r', path.join('clicker', 'requirements.txt'),
    ], { stdio: 'inherit' });

    if (install.status !== 0) {
        log('[deps] pip install failed — the clicker will not work until this is fixed');
        return { ok: false, action: 'failed', python };
    }

    if (run(python, ['-c', 'import pyautogui']).status !== 0) {
        log('[deps] pip reported success but pyautogui still does not import');
        return { ok: false, action: 'failed', python };
    }

    writeFileSync(HASH_FILE, wanted + '\n');
    log('[deps] clicker dependencies ready');
    return { ok: true, action: 'installed', python };
}

// Allow `node scripts/ensure-python-deps.mjs` directly.
if (import.meta.url === `file://${process.argv[1]}`) {
    const result = ensurePythonDeps({ force: process.argv.includes('--force') });
    console.log(JSON.stringify(result));
    process.exit(result.ok ? 0 : 1);
}