<?php
header('Content-Type: application/json');

// Allow CORS for Figma plugin / external scripts
header('Access-Control-Allow-Origin: *');
header('Access-Control-Allow-Methods: POST, GET, OPTIONS');
header('Access-Control-Allow-Headers: Content-Type');

if ($_SERVER['REQUEST_METHOD'] === 'OPTIONS') { exit; }

$uploadDir = __DIR__ . '/uploads/';
$outputDir = __DIR__ . '/output/';
$pythonBin = __DIR__ . '/venv/bin/python3';
$encoderScript = __DIR__ . '/encoder.py';

if (!is_dir($uploadDir)) mkdir($uploadDir, 0755, true);
if (!is_dir($outputDir)) mkdir($outputDir, 0755, true);

// ──────────────────────────────────────────────
// FORM-BASED (frontend UI)
// ──────────────────────────────────────────────
if ($_SERVER['REQUEST_METHOD'] === 'POST' && isset($_POST['action'])) {

    if ($_POST['action'] === 'upload') {
        $uploaded = [];
        if (isset($_FILES['files'])) {
            $batchId = uniqid('batch_');
            $batchDir = $uploadDir . $batchId . '/';
            mkdir($batchDir, 0755, true);

            foreach ($_FILES['files']['tmp_name'] as $i => $tmpName) {
                $originalName = $_FILES['files']['name'][$i];
                $ext = strtolower(pathinfo($originalName, PATHINFO_EXTENSION));
                if ($ext !== 'png') continue;
                if ($_FILES['files']['error'][$i] !== UPLOAD_ERR_OK) continue;

                $safeName = preg_replace('/[^a-zA-Z0-9._-]/', '_', $originalName);
                $destPath = $batchDir . $safeName;
                move_uploaded_file($tmpName, $destPath);

                $uploaded[] = [
                    'name' => $originalName,
                    'file' => $safeName,
                    'batchId' => $batchId,
                    'preview' => 'uploads/' . $batchId . '/' . $safeName,
                ];
            }
        }
        echo json_encode(['success' => true, 'files' => $uploaded, 'batchId' => $batchId ?? null]);
        exit;
    }

    if ($_POST['action'] === 'generate') {
        $groups = json_decode($_POST['groups'], true);
        $quality = intval($_POST['quality'] ?? 256);
        $batchId = $_POST['batchId'] ?? '';

        if (!$groups || !$batchId) {
            echo json_encode(['success' => false, 'error' => 'Missing groups or batchId']);
            exit;
        }

        $results = processGroups($groups, $batchId, $quality);
        echo json_encode(['success' => true, 'results' => $results]);
        exit;
    }
}

// ──────────────────────────────────────────────
// JSON API (Figma plugin / scripts)
// ──────────────────────────────────────────────
// POST /api.php with JSON body or multipart with json field
if ($_SERVER['REQUEST_METHOD'] === 'POST' && !isset($_POST['action'])) {
    $json = null;

    // Check for JSON body
    $rawBody = file_get_contents('php://input');
    if ($rawBody) {
        $json = json_decode($rawBody, true);
    }

    // Check for multipart with 'json' field + file uploads
    if (!$json && isset($_POST['json'])) {
        $json = json_decode($_POST['json'], true);
    }

    if ($json && isset($json['groups'])) {
        $batchId = uniqid('api_');
        $batchDir = $uploadDir . $batchId . '/';
        mkdir($batchDir, 0755, true);

        $quality = intval($json['quality'] ?? 256);
        $groups = $json['groups'] ?? [];

        // Handle file uploads (multipart) — files[] keyed by original name
        if (isset($_FILES['files'])) {
            foreach ($_FILES['files']['tmp_name'] as $i => $tmpName) {
                $originalName = $_FILES['files']['name'][$i];
                $ext = strtolower(pathinfo($originalName, PATHINFO_EXTENSION));
                if ($ext !== 'png') continue;
                if ($_FILES['files']['error'][$i] !== UPLOAD_ERR_OK) continue;
                $safeName = preg_replace('/[^a-zA-Z0-9._-]/', '_', $originalName);
                move_uploaded_file($tmpName, $batchDir . $safeName);
            }
        }

        // Handle base64 encoded files from JSON body
        if (isset($json['files'])) {
            foreach ($json['files'] as $fileName => $base64Data) {
                $safeName = preg_replace('/[^a-zA-Z0-9._-]/', '_', $fileName);
                $data = base64_decode($base64Data);
                if ($data !== false) {
                    file_put_contents($batchDir . $safeName, $data);
                }
            }
        }

        $results = processGroups($groups, $batchId, $quality);

        // For API responses, include base64 GIF data so caller doesn't need a second request
        $baseUrl = (isset($_SERVER['HTTPS']) && $_SERVER['HTTPS'] === 'on' ? 'https' : 'http')
            . '://' . $_SERVER['HTTP_HOST'] . dirname($_SERVER['SCRIPT_NAME']);

        foreach ($results as &$r) {
            if ($r['success'] && isset($r['url'])) {
                $filePath = __DIR__ . '/' . $r['url'];
                if (file_exists($filePath)) {
                    $r['base64'] = base64_encode(file_get_contents($filePath));
                    $r['download_url'] = rtrim($baseUrl, '/') . '/' . $r['url'];
                }
            }
        }

        echo json_encode(['success' => true, 'batchId' => $batchId, 'results' => $results]);
        exit;
    }
}

// ──────────────────────────────────────────────
// Download
// ──────────────────────────────────────────────
if ($_SERVER['REQUEST_METHOD'] === 'GET' && isset($_GET['download'])) {
    $file = $outputDir . basename(dirname($_GET['download'])) . '/' . basename($_GET['download']);
    if (file_exists($file) && pathinfo($file, PATHINFO_EXTENSION) === 'gif') {
        header('Content-Type: image/gif');
        header('Content-Disposition: attachment; filename="' . basename($file) . '"');
        readfile($file);
        exit;
    }
    http_response_code(404);
    echo json_encode(['error' => 'File not found']);
    exit;
}

http_response_code(400);
echo json_encode(['error' => 'Invalid request']);

// ──────────────────────────────────────────────
// Shared encoder logic
// ──────────────────────────────────────────────
function processGroups($groups, $batchId, $quality) {
    global $uploadDir, $outputDir, $pythonBin, $encoderScript;

    $batchDir = $uploadDir . basename($batchId) . '/';
    if (!is_dir($batchDir)) return [['success' => false, 'error' => 'Batch not found']];

    $outputBatchDir = $outputDir . basename($batchId) . '/';
    if (!is_dir($outputBatchDir)) mkdir($outputBatchDir, 0755, true);

    $results = [];
    foreach ($groups as $groupName => $groupData) {
        $files = $groupData['files'] ?? [];
        $loop = $groupData['loop'] ?? true;
        if (empty($files)) continue;

        // Per-frame delays: array or single value
        $delays = $groupData['delays'] ?? [];
        $defaultDelay = intval($groupData['delay'] ?? 500);

        $inputPaths = [];
        foreach ($files as $file) {
            $path = $batchDir . basename($file);
            if (file_exists($path)) {
                $inputPaths[] = escapeshellarg($path);
            }
        }

        if (empty($inputPaths)) {
            $results[] = ['group' => $groupName, 'success' => false, 'error' => 'No valid files'];
            continue;
        }

        $safeGroupName = preg_replace('/[^a-zA-Z0-9._-]/', '_', $groupName);
        $outputFile = $outputBatchDir . $safeGroupName . '.gif';

        $cmd = escapeshellarg($pythonBin) . ' ' . escapeshellarg($encoderScript)
            . ' --input ' . implode(' ', $inputPaths)
            . ' --output ' . escapeshellarg($outputFile)
            . ' --quality ' . intval($quality);

        // Use per-frame delays if provided, otherwise uniform
        if (!empty($delays) && is_array($delays)) {
            $delayStr = implode(',', array_map('intval', $delays));
            $cmd .= ' --delays ' . escapeshellarg($delayStr);
        } else {
            $cmd .= ' --delay ' . intval($defaultDelay);
        }

        if (!$loop) {
            $cmd .= ' --no-loop';
        }

        $cmd .= ' 2>&1';
        $output = shell_exec($cmd);
        $result = json_decode($output, true);

        if ($result && $result['success']) {
            $results[] = [
                'group' => $groupName,
                'success' => true,
                'url' => 'output/' . basename($batchId) . '/' . $safeGroupName . '.gif',
                'frames' => $result['frames'],
            ];
        } else {
            $results[] = [
                'group' => $groupName,
                'success' => false,
                'error' => $result['error'] ?? $output ?? 'Unknown error',
            ];
        }
    }

    return $results;
}