<?php
declare(strict_types=1);

header('Content-Type: application/json; charset=utf-8');

if (session_status() === PHP_SESSION_NONE) {
	session_start();
}

require_once __DIR__ . '/../db_conn.php';

$memberId    = (string)($_SESSION['member_id'] ?? '');
$sysCompCode = (string)($_SESSION['sys_comp_code'] ?? '');

if ($memberId === '') {
	http_response_code(401);
	echo json_encode(['success' => false, 'message' => 'not_logged_in'], JSON_UNESCAPED_UNICODE);
	exit;
}

$contentId = trim((string)($_GET['content_id'] ?? ''));
if ($contentId === '') {
	http_response_code(400);
	echo json_encode(['success' => false, 'message' => 'content_id_required'], JSON_UNESCAPED_UNICODE);
	exit;
}

try {
	$pdo = db_conn();

	$normCode = static function (string $code): string {
		return preg_replace('/[^A-Z0-9]/', '', strtoupper(trim($code)));
	};
	$looksLikeCode = static function (string $value): bool {
		return preg_match('/^[A-Z]{2}[A-Z0-9]{3,}$/', strtoupper(trim($value))) === 1;
	};
	$codeMap = [];
	try {
		$stmtCodeMap = $pdo->query("SELECT base_code, code_name FROM edu_codes");
		foreach ($stmtCodeMap->fetchAll(PDO::FETCH_ASSOC) as $cr) {
			$key = $normCode((string)($cr['base_code'] ?? ''));
			if ($key === '') continue;
			$codeMap[$key] = (string)($cr['code_name'] ?? '');
		}
	} catch (Throwable $ignore) {
		$codeMap = [];
	}

	// 1) 현재 영상의 키워드 코드 조회
	$keywordCodes = [];
	try {
		$stmtKw = $pdo->prepare('SELECT keyword_code FROM edu_content_keywords WHERE content_id = ?');
		$stmtKw->execute([$contentId]);
		$keywordCodes = $stmtKw->fetchAll(PDO::FETCH_COLUMN) ?: [];
	} catch (Throwable $kwErr) {
		// edu_content_keywords 테이블이 없는 경우 무시 → fallback
		$keywordCodes = [];
	}

	// 키워드 없으면 같은 카테고리 영상으로 fallback
	if (empty($keywordCodes)) {
		// 현재 영상의 카테고리 조회
		$stmtCat = $pdo->prepare('SELECT category_code FROM edu_contents WHERE content_id = ? LIMIT 1');
		$stmtCat->execute([$contentId]);
		$curCatCode = $stmtCat->fetchColumn();

		if (!$curCatCode) {
			echo json_encode([
				'success'  => true,
				'keywords' => [],
				'videos'   => [],
			], JSON_UNESCAPED_UNICODE);
			exit;
		}

		$stmtFallback = $pdo->prepare(
			"SELECT c.content_id, c.title, c.content_url, c.thumbnail_url,
			        c.category_code, c.category_group, c.description,
			        COALESCE(ec.code_name, c.category_code) AS category_name,
			        COALESCE(ec_grp.code_name, c.category_group) AS category_group_name
			 FROM edu_contents c
			 LEFT JOIN edu_codes ec ON TRIM(UPPER(ec.base_code)) = TRIM(UPPER(c.category_code))
			 LEFT JOIN edu_codes ec_grp ON TRIM(UPPER(ec_grp.base_code)) = TRIM(UPPER(c.category_group))
			 WHERE c.category_code = ?
			   AND c.content_id != ?
			   AND c.is_active = 1
			 ORDER BY c.start_date DESC
			 LIMIT 8"
		);
		$stmtFallback->execute([$curCatCode, $contentId]);
		$rows = $stmtFallback->fetchAll(PDO::FETCH_ASSOC) ?: [];

		$videos = [];
		foreach ($rows as $row) {
			$raw = trim($row['content_url'] ?? '');
			$videoId = '';
			if (preg_match('/(?:v=|youtu\.be\/)([A-Za-z0-9_-]{11})/', $raw, $m)) {
				$videoId = $m[1];
			} elseif (preg_match('/^[A-Za-z0-9_-]{11}$/', $raw)) {
				$videoId = $raw;
			}
			$thumbFromDb = trim($row['thumbnail_url'] ?? '');
			$thumbnail = $thumbFromDb !== ''
				? $thumbFromDb
				: ($videoId !== '' ? "https://img.youtube.com/vi/{$videoId}/sddefault.jpg" : '');
			$catCode = $row['category_code'] ?? '';
			$subcate = trim((string)($row['category_group_name'] ?? $row['category_group'] ?? ''));
			$catName = trim((string)($row['category_name'] ?? $catCode));
			if (($catName === '' || $looksLikeCode($catName)) && $catCode !== '') {
				$mapped = $codeMap[$normCode($catCode)] ?? '';
				if ($mapped !== '') $catName = $mapped;
			}
			$groupRaw = trim((string)($row['category_group'] ?? ''));
			if (($subcate === '' || $looksLikeCode($subcate)) && $groupRaw !== '') {
				$mapped = $codeMap[$normCode($groupRaw)] ?? '';
				if ($mapped !== '') $subcate = $mapped;
			}
			$videos[] = [
				'content_id'    => $row['content_id'],
				'title'         => $row['title'] ?? '',
				'content_url'   => $videoId !== '' ? "https://www.youtube.com/watch?v={$videoId}" : $raw,
				'thumbnail'     => $thumbnail,
				'category_code' => $catCode,
				'category'      => $catName,
				'category_name' => $catName,
				'subcate'       => $subcate,
				'description'   => $row['description'] ?? '',
			];
		}

		echo json_encode([
			'success'  => true,
			'keywords' => [],
			'videos'   => $videos,
		], JSON_UNESCAPED_UNICODE);
		exit;
	}

	// 2) 키워드명 조회 (표시용)
	$kwPlaceholders = implode(',', array_fill(0, count($keywordCodes), '?'));
	$keywordNames = [];
	try {
		$stmtKwNames = $pdo->prepare(
			"SELECT keyword_code, keyword_name FROM edu_keywords WHERE keyword_code IN ({$kwPlaceholders})"
		);
		$stmtKwNames->execute($keywordCodes);
		while ($row = $stmtKwNames->fetch(PDO::FETCH_ASSOC)) {
			$keywordNames[] = $row['keyword_name'];
		}
	} catch (Throwable $kwNameErr) {
		$keywordNames = [];
	}

	// 3) 동일 키워드를 가진 다른 영상 조회 (현재 영상 제외, 랜덤 8개)
	$rows = [];
	try {
		$stmtVideos = $pdo->prepare(
			"SELECT DISTINCT
				c.content_id,
				c.title,
				c.content_url,
				c.thumbnail_url,
				c.category_code,
				c.category_group,
				c.description,
				COALESCE(ec.code_name, c.category_code) AS category_name,
				COALESCE(ec_grp.code_name, c.category_group) AS category_group_name
			FROM edu_contents c
			LEFT JOIN edu_codes ec ON TRIM(UPPER(ec.base_code)) = TRIM(UPPER(c.category_code))
			LEFT JOIN edu_codes ec_grp ON TRIM(UPPER(ec_grp.base_code)) = TRIM(UPPER(c.category_group))
			INNER JOIN edu_content_keywords ck ON ck.content_id = c.content_id
			WHERE ck.keyword_code IN ({$kwPlaceholders})
			  AND c.content_id != ?
			  AND c.is_active = 1
			ORDER BY RAND()
			LIMIT 8"
		);
		$params = array_merge($keywordCodes, [$contentId]);
		$stmtVideos->execute($params);
		$rows = $stmtVideos->fetchAll(PDO::FETCH_ASSOC) ?: [];
	} catch (Throwable $kwVideoErr) {
		$rows = [];
	}

	// 키워드 매칭 결과 없으면 같은 카테고리 fallback
	if (empty($rows)) {
		$stmtCat = $pdo->prepare('SELECT category_code FROM edu_contents WHERE content_id = ? LIMIT 1');
		$stmtCat->execute([$contentId]);
		$curCatCode = $stmtCat->fetchColumn();
		if ($curCatCode) {
			$stmtFb = $pdo->prepare(
				"SELECT c.content_id, c.title, c.content_url, c.thumbnail_url,
				        c.category_code, c.category_group, c.description,
				        COALESCE(ec.code_name, c.category_code) AS category_name,
				        COALESCE(ec_grp.code_name, c.category_group) AS category_group_name
				 FROM edu_contents c
				 LEFT JOIN edu_codes ec ON TRIM(UPPER(ec.base_code)) = TRIM(UPPER(c.category_code))
				 LEFT JOIN edu_codes ec_grp ON TRIM(UPPER(ec_grp.base_code)) = TRIM(UPPER(c.category_group))
				 WHERE c.category_code = ?
				   AND c.content_id != ?
				   AND c.is_active = 1
				 ORDER BY c.start_date DESC
				 LIMIT 8"
			);
			$stmtFb->execute([$curCatCode, $contentId]);
			$rows = $stmtFb->fetchAll(PDO::FETCH_ASSOC) ?: [];
		}
	}

	$videos = [];
	foreach ($rows as $row) {
		$raw = trim($row['content_url'] ?? '');
		$videoId = '';
		if (preg_match('/(?:v=|youtu\.be\/)([A-Za-z0-9_-]{11})/', $raw, $m)) {
			$videoId = $m[1];
		} elseif (preg_match('/^[A-Za-z0-9_-]{11}$/', $raw)) {
			$videoId = $raw;
		}

		$thumbFromDb = trim($row['thumbnail_url'] ?? '');
		$thumbnail = $thumbFromDb !== ''
			? $thumbFromDb
			: ($videoId !== '' ? "https://img.youtube.com/vi/{$videoId}/sddefault.jpg" : '');

		$catCode = $row['category_code'] ?? '';
		$subcate = trim((string)($row['category_group_name'] ?? $row['category_group'] ?? ''));
		$catName = trim((string)($row['category_name'] ?? $catCode));
		if (($catName === '' || $looksLikeCode($catName)) && $catCode !== '') {
			$mapped = $codeMap[$normCode($catCode)] ?? '';
			if ($mapped !== '') $catName = $mapped;
		}
		$groupRaw = trim((string)($row['category_group'] ?? ''));
		if (($subcate === '' || $looksLikeCode($subcate)) && $groupRaw !== '') {
			$mapped = $codeMap[$normCode($groupRaw)] ?? '';
			if ($mapped !== '') $subcate = $mapped;
		}

		$videos[] = [
			'content_id'    => $row['content_id'],
			'title'         => $row['title'] ?? '',
			'content_url'   => $videoId !== '' ? "https://www.youtube.com/watch?v={$videoId}" : $raw,
			'thumbnail'     => $thumbnail,
			'category_code' => $catCode,
			'category'      => $catName,
			'category_name' => $catName,
			'subcate'       => $subcate,
			'description'   => $row['description'] ?? '',
		];
	}

	echo json_encode([
		'success'  => true,
		'keywords' => $keywordNames,
		'videos'   => $videos,
	], JSON_UNESCAPED_UNICODE);

} catch (Throwable $e) {
	error_log('[get_recommend_videos] ' . $e->getMessage());
	http_response_code(500);
	echo json_encode(['success' => false, 'message' => 'server_error'], JSON_UNESCAPED_UNICODE);
}