KCI-CAMPAIGN-TRACKER/app/Services/GoogleSheetImportService.php

<?php

declare(strict_types=1);

namespace App\Services;

use RuntimeException;

class GoogleSheetImportService
{
    /**
     * @return array{id: string, sheets: list<array{gid: string, title: string}>}
     */
    public function sheets(string $url): array
    {
        $spreadsheetId = $this->spreadsheetId($url);
        $currentGid    = $this->gidFromUrl($url);
        $sheets        = [];

        // Strategy 1: v3 worksheets JSON feed — works for publicly published sheets.
        // Each entry's alternate link href contains the numeric gid.
        if ($sheets === []) {
            try {
                $feed   = $this->fetch(
                    'https://spreadsheets.google.com/feeds/worksheets/'
                    . rawurlencode($spreadsheetId) . '/public/basic?alt=json'
                );
                $sheets = $this->extractSheetsFromFeed($feed);
            } catch (\Throwable) {}
        }

        // Strategy 2: htmlview URL — serves rendered HTML with tab links for
        // sheets shared "anyone with the link can view".
        if ($sheets === []) {
            try {
                $html   = $this->fetch(
                    'https://docs.google.com/spreadsheets/d/'
                    . rawurlencode($spreadsheetId) . '/htmlview'
                );
                $sheets = $this->extractSheets($html);
            } catch (\Throwable) {}
        }

        // Strategy 3: edit URL JS-bootstrapped data — last resort.
        if ($sheets === []) {
            try {
                $html   = $this->fetch(
                    'https://docs.google.com/spreadsheets/d/'
                    . rawurlencode($spreadsheetId) . '/edit?usp=sharing'
                );
                $sheets = $this->extractSheets($html);
            } catch (\Throwable) {}
        }

        // Fallback: if we know the gid from the URL, return a labelled placeholder.
        if ($sheets === [] && $currentGid !== null) {
            $sheets[] = ['gid' => $currentGid, 'title' => 'Sheet ' . $currentGid];
        }

        if ($sheets === []) {
            $sheets[] = ['gid' => '0', 'title' => 'First sheet'];
        }

        return ['id' => $spreadsheetId, 'sheets' => $sheets];
    }

    /**
     * @return array{headers: list<string>, rows: list<array<string, string>>}
     */
    public function rows(string $url, string $gid): array
    {
        $spreadsheetId = $this->spreadsheetId($url);
        $csv = $this->fetch(sprintf(
            'https://docs.google.com/spreadsheets/d/%s/export?format=csv&gid=%s',
            rawurlencode($spreadsheetId),
            rawurlencode($gid)
        ));

        return $this->parseCsv($csv);
    }

    public function spreadsheetId(string $url): string
    {
        $parts = parse_url($url);
        $host  = strtolower((string) ($parts['host'] ?? ''));

        if (!in_array($host, ['docs.google.com', 'spreadsheets.google.com'], true)) {
            throw new RuntimeException('Enter a valid Google Sheets URL.');
        }

        $path = (string) ($parts['path'] ?? '');
        if (preg_match('#/spreadsheets/d/([a-zA-Z0-9_-]+)#', $path, $matches) !== 1) {
            throw new RuntimeException('The Google Sheets URL does not include a spreadsheet id.');
        }

        return $matches[1];
    }

    // ── Sheet extraction ──────────────────────────────────────────────────────

    /**
     * Parse the v3 JSON feed response.
     *
     * @return list<array{gid: string, title: string}>
     */
    private function extractSheetsFromFeed(string $json): array
    {
        $data = json_decode($json, true);

        if (!is_array($data) || !isset($data['feed']['entry'])) {
            return [];
        }

        $sheets = [];

        foreach ((array) $data['feed']['entry'] as $entry) {
            $title = (string) ($entry['title']['$t'] ?? '');

            if ($title === '') {
                continue;
            }

            // GID is embedded in the rel="alternate" link href as #gid=NNN or &gid=NNN
            $gid = null;
            foreach ((array) ($entry['link'] ?? []) as $link) {
                if (preg_match('/[#&]gid=(\d+)/', (string) ($link['href'] ?? ''), $m)) {
                    $gid = $m[1];
                    break;
                }
            }

            if ($gid !== null && $this->looksLikeSheet($gid, $title) && !isset($sheets[$gid])) {
                $sheets[$gid] = ['gid' => $gid, 'title' => $title];
            }
        }

        return array_values($sheets);
    }

    /**
     * Parse HTML from htmlview or edit URL for sheet tab data.
     *
     * @return list<array{gid: string, title: string}>
     */
    private function extractSheets(string $html): array
    {
        $sheets = [];

        // ── HTML tab patterns (htmlview format) ───────────────────────────────
        // Google renders tab links like:
        //   <a href="#gid=123">Sheet Name</a>
        //   <span data-id="123">Sheet Name</span>
        $htmlPatterns = [
            '/<[^>]+href=["\'][^"\']*[#&]gid=(\d+)["\'][^>]*>\s*(?:<[^>]+>\s*)*([^<]{1,100}?)\s*(?:<|$)/i',
            '/data-id=["\'](\d+)["\'][^>]*>\s*([^<]{1,100}?)\s*</i',
        ];

        foreach ($htmlPatterns as $pattern) {
            if (preg_match_all($pattern, $html, $matches, PREG_SET_ORDER) > 0) {
                foreach ($matches as $match) {
                    $gid   = $match[1];
                    $title = trim(html_entity_decode($match[2], ENT_QUOTES | ENT_HTML5, 'UTF-8'));
                    if ($this->looksLikeSheet($gid, $title) && !isset($sheets[$gid])) {
                        $sheets[$gid] = ['gid' => $gid, 'title' => $title];
                    }
                }
            }
        }

        if (!empty($sheets)) {
            return array_values($sheets);
        }

        // ── JavaScript JSON patterns (edit URL bootstrapped data) ─────────────
        // Distance increased to 600 chars to handle larger embedded JSON objects.
        $jsPatterns = [
            '/"gid"\s*:\s*(\d+).{0,600}?"name"\s*:\s*"((?:\\\\.|[^"\\\\])+)"/s',
            '/"name"\s*:\s*"((?:\\\\.|[^"\\\\])+)".{0,600}?"gid"\s*:\s*(\d+)/s',
            '/"gid"\s*:\s*(\d+).{0,600}?"title"\s*:\s*"((?:\\\\.|[^"\\\\])+)"/s',
            '/"title"\s*:\s*"((?:\\\\.|[^"\\\\])+)".{0,600}?"gid"\s*:\s*(\d+)/s',
            '/\[\s*(\d+)\s*,\s*"((?:\\\\.|[^"\\\\])+)"/s',
        ];

        foreach ($jsPatterns as $pattern) {
            if (preg_match_all($pattern, $html, $matches, PREG_SET_ORDER) > 0) {
                foreach ($matches as $match) {
                    $first  = (string) $match[1];
                    $second = (string) $match[2];
                    $gid    = ctype_digit($first) ? $first : $second;
                    $title  = ctype_digit($first) ? $second : $first;
                    $title  = $this->decodeJsString($title);

                    if (!$this->looksLikeSheet($gid, $title) || isset($sheets[$gid])) {
                        continue;
                    }

                    $sheets[$gid] = ['gid' => $gid, 'title' => $title];
                }

                if (!empty($sheets)) {
                    break;
                }
            }
        }

        return array_values($sheets);
    }

    private function looksLikeSheet(string $gid, string $title): bool
    {
        if ($gid === '' || !ctype_digit($gid) || $title === '' || strlen($title) > 120) {
            return false;
        }

        return !str_contains($title, '<')
            && !str_contains($title, '{')
            && !str_contains(strtolower($title), 'http');
    }

    private function decodeJsString(string $value): string
    {
        $decoded = json_decode('"' . str_replace('"', '\\"', $value) . '"', true);

        return is_string($decoded) ? $decoded : stripcslashes($value);
    }

    private function gidFromUrl(string $url): ?string
    {
        $fragment = parse_url($url, PHP_URL_FRAGMENT);
        $query    = parse_url($url, PHP_URL_QUERY);

        foreach ([(string) $fragment, (string) $query] as $part) {
            if (preg_match('/(?:^|&)gid=(\d+)/', $part, $matches) === 1) {
                return $matches[1];
            }
        }

        return null;
    }

    // ── HTTP fetch ────────────────────────────────────────────────────────────

    private function fetch(string $url): string
    {
        $context = stream_context_create([
            'http' => [
                'method'          => 'GET',
                'timeout'         => 15,
                'ignore_errors'   => true,
                'follow_location' => true,
                'max_redirects'   => 5,
                'header'          => implode("\r\n", [
                    'User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/124.0.0.0 Safari/537.36',
                    'Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
                    'Accept-Language: en-US,en;q=0.5',
                ]) . "\r\n",
            ],
        ]);

        $content = @file_get_contents($url, false, $context);

        if (!is_string($content) || trim($content) === '') {
            throw new RuntimeException(
                'Could not reach the Google Sheet. Check the URL and make sure the sheet is shared as "Anyone with the link can view".'
            );
        }

        // Google returns a sign-in page when the sheet requires authentication.
        // Detect this by looking for the login shell markers present in every
        // Google auth redirect (~9 KB of CSS/JS with no actual sheet data).
        if (
            str_contains($content, '.login,.request-storage-access') ||
            str_contains($content, 'ServiceLogin') ||
            str_contains($content, 'accounts.google.com/ServiceLogin')
        ) {
            throw new RuntimeException(
                'Google returned a sign-in page. The spreadsheet must be shared as "Anyone with the link can view": '
                . 'open the sheet → File → Share → Change to "Anyone with the link" → Viewer.'
            );
        }

        return $content;
    }

    // ── CSV parsing ───────────────────────────────────────────────────────────

    /**
     * @return array{headers: list<string>, rows: list<array<string, string>>}
     */
    private function parseCsv(string $csv): array
    {
        $handle = fopen('php://temp', 'r+');
        if ($handle === false) {
            throw new RuntimeException('Unable to parse sheet data.');
        }

        fwrite($handle, $csv);
        rewind($handle);

        $headers = fgetcsv($handle);
        if ($headers === false) {
            fclose($handle);
            throw new RuntimeException('The selected sheet is empty.');
        }

        $headers = array_map(
            static fn($h): string => trim((string) $h, " \t\n\r\0\x0B\xEF\xBB\xBF"),
            $headers
        );

        $rows = [];
        while (($values = fgetcsv($handle)) !== false) {
            $row      = [];
            $hasValue = false;

            foreach ($headers as $index => $header) {
                if ($header === '') {
                    continue;
                }

                $value          = trim((string) ($values[$index] ?? ''));
                $row[$header]   = $value;
                $hasValue       = $hasValue || $value !== '';
            }

            if ($hasValue) {
                $rows[] = $row;
            }
        }

        fclose($handle);

        return ['headers' => $headers, 'rows' => $rows];
    }
}