<?php
require_once __DIR__ . '/../lib/identity.php';
require_once __DIR__ . '/../lib/jobs.php';

[$actor, $vendor_id] = resolve_request_actor();

if ($actor === 'ICG') {
    http_response_code(403);
    echo 'Partial ship is a vendor action';
    return;
}

$pdo = db();
$job_id  = (int) ($_POST['job_id'] ?? 0);
$partial = (int) ($_POST['partial_qty'] ?? 0);

if ($job_id <= 0 || $partial <= 0) {
    http_response_code(400);
    echo 'Bad parameters';
    return;
}

$stmt = $pdo->prepare('SELECT * FROM jobs WHERE id = ?');
$stmt->execute([$job_id]);
$job = $stmt->fetch();
if (!$job) {
    http_response_code(404);
    echo 'Job not found';
    return;
}
if (!empty($job['deleted_at'])) {
    http_response_code(410);
    echo 'Job has been deleted';
    return;
}

if ((int) $job['vendor_id'] !== $vendor_id) {
    http_response_code(403);
    echo 'Wrong vendor';
    return;
}

if (!in_array($job['status'], ['', 'Finished'], true)) {
    http_response_code(400);
    echo 'Can only partial-ship from open or finished status';
    return;
}

$current_qty = (int) $job['qty'];
if ($partial >= $current_qty) {
    http_response_code(400);
    echo 'Partial quantity must be less than current quantity (' . $current_qty . ')';
    return;
}

// BEGIN IMMEDIATE + retry mirrors the apply_job_change pattern.
$attempts = 0;
while (true) {
    $attempts++;
    try {
        $pdo->exec('BEGIN IMMEDIATE');
        break;
    } catch (PDOException $e) {
        if ($attempts >= 50 || !is_busy_error($e)) throw $e;
        usleep(100000);
    }
}

try {
    $remaining = $current_qty - $partial;

    // The shipped portion as its own row.
    $ins = $pdo->prepare(
        "INSERT INTO jobs (vendor_id, job, material, description, qty, due_date, ack, status)
         VALUES (?, ?, ?, ?, ?, ?, '', 'Shipped')"
    );
    $ins->execute([
        $job['vendor_id'], $job['job'], $job['material'], $job['description'],
        $partial, $job['due_date']
    ]);
    $new_id = (int) $pdo->lastInsertId();

    // Deduct from the original; keep its current status.
    $upd = $pdo->prepare(
        "UPDATE jobs SET qty = ?, updated_at = datetime('now') WHERE id = ?"
    );
    $upd->execute([$remaining, $job_id]);

    // Audit trail covering both rows so the log page can reconstruct the split.
    $hist = $pdo->prepare(
        'INSERT INTO job_history (job_id, field, old_value, new_value, actor)
         VALUES (?, ?, ?, ?, ?)'
    );
    // The new row was created (this is its first appearance). new_value is the
    // vendor slug, matching the convention from bin/jobs_add.php. The actor is
    // the vendor performing the partial ship, so it doubles as the vendor slug.
    $hist->execute([$new_id, 'created', null, $actor, $actor]);
    // The new row starts Shipped (transition from default '').
    $hist->execute([$new_id, 'status', '',                   'Shipped',           $actor]);
    // The original row lost qty.
    $hist->execute([$job_id, 'qty',    (string) $current_qty, (string) $remaining, $actor]);
    // A linking marker so the log can show "split off N units into job #X".
    $hist->execute([$job_id, 'partial_ship', (string) $current_qty, (string) $partial . ' -> #' . $new_id, $actor]);

    $pdo->exec('COMMIT');
    echo 'Success';
} catch (Throwable $e) {
    $pdo->exec('ROLLBACK');
    throw $e;
}