<?php
/**
 * 数据组装：卷王答卷 -> 学号 / 姓名 / 成绩 / 提交时间 / 考试时长
 */
declare(strict_types=1);

class DataService
{
    /** 容器型题目（分页、题组、说明）不参与取值 */
    private const CONTAINER_TYPES = [
        'pagination', 'page', 'group', 'survey', 'divider', 'tree',
    ];

    /** 题目标题可能是富文本，去掉标签便于展示与匹配 */
    private static function cleanTitle(string $t): string
    {
        $t = strip_tags($t);
        $t = html_entity_decode($t, ENT_QUOTES | ENT_HTML5, 'UTF-8');
        return trim(preg_replace('/\s+/u', ' ', $t) ?? '');
    }

    /**
     * 展平题目树
     * @return array<int,array{id:string,title:string,type:string,path:string}>
     */
    public static function flattenQuestions(mixed $node, string $path = ''): array
    {
        $out = [];
        if (!is_array($node)) {
            return $out;
        }

        // children 在根或子节点
        $self = $node;
        $children = (isset($node['children']) && is_array($node['children'])) ? $node['children'] : null;

        $id    = isset($self['id']) ? (string)$self['id'] : '';
        $title = isset($self['title']) ? self::cleanTitle((string)$self['title']) : '';
        $type  = isset($self['type']) ? (string)$self['type'] : '';

        $isRoot = ($path === '');
        if (!$isRoot && $id !== '' && !in_array(strtolower($type), self::CONTAINER_TYPES, true)) {
            $out[] = [
                'id'    => $id,
                'title' => $title !== '' ? $title : $id,
                'type'  => $type,
                'path'  => $path,
            ];
        }

        if ($children !== null) {
            foreach ($children as $idx => $child) {
                $subPath = $path === '' ? (string)($idx + 1) : $path . '-' . ($idx + 1);
                foreach (self::flattenQuestions($child, $subPath) as $q) {
                    $out[] = $q;
                }
            }
        }
        return $out;
    }

    /** 根据关键词猜测"姓名"题 */
    public static function guessNameQuestion(array $questions, string $keywords): array
    {
        $kws = array_values(array_filter(array_map('trim', preg_split('/[,，]/u', $keywords) ?: [])));
        $candidates = [];
        foreach ($questions as $q) {
            $t = (string)$q['title'];
            foreach ($kws as $kw) {
                if ($kw !== '' && mb_stripos($t, $kw) !== false) {
                    $candidates[] = $q;
                    break;
                }
            }
        }
        return $candidates;
    }

    /**
     * 组装结果
     */
    public static function build(array $cfg, string $projectId, string $nameQid = ''): array
    {
        $client = new SurveyKingClient($cfg);

        $students = Roster::all();
        // 姓名 -> 学号 / 班级（规范化）
        $studentInfo = [];
        foreach ($students as $s) {
            $k = ny_norm_name((string)$s['name']);
            if ($k !== '') {
                $studentInfo[$k] = [
                    'sid' => (string)$s['sid'],
                    'cls' => (string)($s['cls'] ?? ''),
                    'grp' => (string)($s['grp'] ?? ''),
                ];
            }
        }

        $project   = $client->getProject($projectId);
        $survey    = $project['survey'] ?? null;
        if (is_string($survey) && $survey !== '') {
            $decoded = json_decode($survey, true);
            if (is_array($decoded)) {
                $survey = $decoded;
            }
        }
        $questions = self::flattenQuestions($survey);

        $keywords      = (string)($cfg['name_keywords'] ?? '姓名');
        $nameCandidates = self::guessNameQuestion($questions, $keywords);
        $autoQid = $nameCandidates[0]['id'] ?? '';

        // 指定优先
        $pickedQid = $nameQid !== '' ? $nameQid : $autoQid;
        $candidateIds = [];
        if ($pickedQid !== '') {
            $candidateIds[] = $pickedQid;
        }
        foreach ($nameCandidates as $q) {
            if (!in_array($q['id'], $candidateIds, true)) {
                $candidateIds[] = $q['id'];
            }
        }

        $answers = $client->listAnswers($projectId);

        $includeTemp = !empty($cfg['include_temp_save']);
        $dedupe      = !empty($cfg['dedupe']);

        $rows      = [];
        $unmatched = [];
        $seenSid   = [];

        foreach ($answers as $a) {
            $tempSave = isset($a['tempSave']) ? (int)$a['tempSave'] : 1;
            if (!$includeTemp && $tempSave === 0) {
                continue; // 跳过暂存
            }
            $answerMap = isset($a['answer']) && is_array($a['answer']) ? $a['answer'] : [];

            // 姓名：优先关键词命中的题目 -> 全量扫描能匹配名单的答案 -> 登录用户名
            $name = '';
            foreach ($candidateIds as $qid) {
                if (isset($answerMap[$qid])) {
                    $v = ny_flatten_value($answerMap[$qid]);
                    if ($v !== '') {
                        $name = $v;
                        break;
                    }
                }
            }
            if ($name === '') {
                foreach ($questions as $q) {
                    $qid = (string)$q['id'];
                    if (!array_key_exists($qid, $answerMap)) {
                        continue;
                    }
                    $v = ny_flatten_value($answerMap[$qid]);
                    if ($v !== '' && isset($nameMap[ny_norm_name($v)])) {
                        $name = $v;
                        break;
                    }
                }
            }
            if ($name === '' && $questions === []) {
                foreach ($answerMap as $v) {
                    $s = ny_flatten_value($v);
                    if ($s !== '' && isset($nameMap[ny_norm_name($s)])) {
                        $name = $s;
                        break;
                    }
                }
            }
            if ($name === '') {
                $name = ny_str($a['createByName'] ?? '');
            }
            if ($name === '') {
                $name = '（未填写姓名）';
            }

            // 成绩
            $score = null;
            if (isset($a['examScore']) && is_numeric($a['examScore'])) {
                $score = (float)$a['examScore'];
            }

            // 提交时间
            $ts = ny_to_timestamp($a['createAt'] ?? null);
            if ($ts === 0) {
                $ts = ny_to_timestamp($a['updateAt'] ?? null);
            }

            // 考试时长
            $ai    = $a['metaInfo']['answerInfo'] ?? [];
            $start = is_array($ai) ? (int)($ai['startTime'] ?? 0) : 0;
            $end   = is_array($ai) ? (int)($ai['endTime'] ?? 0) : 0;
            $dur   = null;
            if ($start > 0 && $end > $start) {
                $dur = (int)round(($end - $start) / 1000);
            }

            $key = ny_norm_name($name);
            $info = $studentInfo[$key] ?? null;
            $sid = $info['sid'] ?? '';
            $cls = $info['cls'] ?? '';
            $grp = $info['grp'] ?? '';

            $row = [
                'sid'         => $sid,
                'name'        => $name,
                'cls'         => $cls,
                'grp'         => $grp,
                'score'       => $score,
                'submit_ts'   => $ts,
                'submit_at'   => $ts > 0 ? date('Y-m-d H:i:s', $ts) : '-',
                'duration'    => $dur,
                'duration_txt'=> ny_format_duration($dur),
                'answer_id'   => ny_str($a['id'] ?? ''),
                'matched'     => $sid !== '',
                'temp_save'   => $tempSave === 0,
            ];

            if ($sid === '') {
                $unmatched[] = $row;
                continue;
            }

            if ($dedupe && isset($seenSid[$sid])) {
                $idx = $seenSid[$sid];
                // 保留提交时间最新的一份
                if ($ts >= ($rows[$idx]['submit_ts'] ?? 0)) {
                    $rows[$idx] = $row;
                    $seenSid[$sid] = $idx;
                }
                continue;
            }
            $seenSid[$sid] = count($rows);
            $rows[] = $row;
        }

        // 成绩明细默认按提交时间降序（最新在前），学号作为次级排序
        usort($rows, static function (array $x, array $y): int {
            $d = ($y['submit_ts'] ?? 0) <=> ($x['submit_ts'] ?? 0);
            if ($d !== 0) {
                return $d;
            }
            $a = (string)$x['sid'];
            $b = (string)$y['sid'];
            if (is_numeric($a) && is_numeric($b)) {
                return $a <=> $b;
            }
            return strnatcmp($a, $b);
        });

        // 缺考名单
        $submittedSids = [];
        foreach ($rows as $r) {
            $submittedSids[(string)$r['sid']] = true;
        }
        $absent = [];
        foreach ($students as $s) {
            if (!isset($submittedSids[(string)$s['sid']])) {
                $absent[] = [
                    'sid'  => (string)$s['sid'],
                    'name' => (string)$s['name'],
                    'cls'  => (string)($s['cls'] ?? ''),
                    'grp'  => (string)($s['grp'] ?? ''),
                ];
            }
        }
        usort($absent, static function (array $x, array $y): int {
            $a = (string)$x['sid'];
            $b = (string)$y['sid'];
            if (is_numeric($a) && is_numeric($b)) {
                return $a <=> $b;
            }
            return strnatcmp($a, $b);
        });

        // 统计
        $scores = array_values(array_filter(array_map(static fn($r) => $r['score'], $rows), static fn($v) => $v !== null));
        $durs   = array_values(array_filter(array_map(static fn($r) => $r['duration'], $rows), static fn($v) => $v !== null));
        $stats = [
            'roster_total'  => count($students),
            'submitted'     => count($rows),
            'absent'        => count($absent),
            'unmatched'     => count($unmatched),
            'submit_rate'   => count($students) > 0 ? round(count($rows) / count($students) * 100, 1) : 0,
            'avg_score'     => $scores !== [] ? round(array_sum($scores) / count($scores), 2) : null,
            'max_score'     => $scores !== [] ? max($scores) : null,
            'min_score'     => $scores !== [] ? min($scores) : null,
            'avg_duration'  => $durs !== [] ? (int)round(array_sum($durs) / count($durs)) : null,
            'answer_total'  => count($answers),
        ];

        return [
            'project'    => [
                'id'   => ny_str($project['id'] ?? $projectId),
                'name' => ny_str($project['name'] ?? ''),
                'mode' => ny_str($project['mode'] ?? ''),
            ],
            'questions'  => $questions,
            'name_qid'   => $pickedQid,
            'name_candidates' => array_map(static fn($q) => ['id' => $q['id'], 'title' => $q['title']], $nameCandidates),
            'rows'       => $rows,
            'absent'     => $absent,
            'unmatched'  => $unmatched,
            'stats'      => $stats,
            'roster'     => $students,
            'roster_count' => count($students),
            'updated_at' => date('Y-m-d H:i:s'),
        ];
    }
}