<?php

declare(strict_types=1);

namespace app\adminapi\service;

/** Schema/citation gate. This is not a medical or general semantic correctness proof. */
final class LiveConsultationResult
{
    public const MAX_BYTES = 65536;
    private const GROUPS = ['summary', 'questions', 'checks', 'review'];
    private const LABELS = ['doctor' => '医生原话', 'patient' => '患者原话', 'unknown' => '未知说话人原话'];

    /** Reject malformed structure/invented references; render summary facts only from immutable sources. */
    public static function parse(string $content, array $snapshot, string $task, array $knownChart = [], ?string &$failure = null): ?array
    {
        $failure = null;
        if (strlen($content) > self::MAX_BYTES) return self::reject('LENGTH_LIMIT', $failure);
        $content = trim($content);
        // Accept only an exact, complete JSON code-fence envelope, never surrounding prose/wrappers.
        if (preg_match('/\A```(?:json)?[ \t]*\r?\n([\s\S]*)\r?\n```[ \t]*\z/i', $content, $match) === 1)
            $content = trim($match[1]);
        $scan = self::scanGroups($content);
        if ($scan === null || !$scan['complete']) return self::reject('JSON_INVALID', $failure);
        return self::validate($scan['groups'], $snapshot, $task, $knownChart, $failure);
    }

    /** Complete, delimited items only; absent groups stay empty until a later validated update. */
    public static function progress(string $content, array $snapshot, string $task, array $knownChart = []): ?array
    {
        if (strlen($content) > self::MAX_BYTES) return null;
        $content = ltrim($content);
        $fenced = preg_match('/\A```(?:json)?[ \t]*\r?\n/i', $content, $match) === 1;
        if ($fenced) {
            $content = substr($content, strlen($match[0]));
            $content = preg_replace('/\r?\n```[ \t\r\n]*\z/', '', $content) ?? $content;
        }
        $scan = self::scanGroups($content);
        if ($scan === null || ($scan['completed_groups'] === 0 && !array_filter($scan['groups']))) return null;
        // The same full schema, role, citation and safety gate protects partial delivery.
        $failure = null;
        $result = self::validate(array_replace(array_fill_keys(self::GROUPS, []), $scan['groups']),
            $snapshot, $task, $knownChart, $failure);
        return $result === null ? null : ['completed_groups' => $scan['completed_groups'],
            'displayed_items' => array_sum(array_map('count', $result)), 'assistance' => $result];
    }

    /** Bounded JSON lexer. Reject duplicate/unknown top-level keys instead of json_decode's last-key wins. */
    private static function scanGroups(string $content): ?array
    {
        $length = strlen($content);
        $index = 0;
        $space = static function () use ($content, $length, &$index): void {
            while ($index < $length && str_contains(" \t\r\n", $content[$index])) $index++;
        };
        $space();
        if ($index >= $length || $content[$index++] !== '{') return null;
        $groups = [];
        $completedGroups = 0;
        $pending = static function () use (&$groups, &$completedGroups): array {
            return ['groups' => $groups, 'completed_groups' => $completedGroups, 'complete' => false];
        };
        $afterComma = false;
        while (true) {
            $space();
            if ($index >= $length) return $pending();
            if ($content[$index] === '}') {
                if ($afterComma) return null;
                $index++; $space();
                return $index === $length ? ['groups' => $groups, 'completed_groups' => $completedGroups, 'complete' => true] : null;
            }
            // Plain contract keys only: no alternate spelling, escaping or nested wrapper.
            if (preg_match('/\G"(summary|questions|checks|review)"[ \t\r\n]*:[ \t\r\n]*/A', $content, $key, 0, $index) !== 1) {
                $tail = substr($content, $index);
                // Incomplete key/colon may await another chunk; it cannot yield any new group.
                foreach (self::GROUPS as $group) {
                    if (str_starts_with('"' . $group . '"', rtrim($tail))
                        || preg_match('/\A"' . $group . '"[ \t\r\n]*:?[ \t\r\n]*\z/', $tail) === 1)
                        return $pending();
                }
                return null;
            }
            $group = $key[1];
            if (array_key_exists($group, $groups)) return null;
            $index += strlen($key[0]);
            if ($index >= $length) return $pending();
            if ($content[$index] !== '[') return null;
            $groups[$group] = [];
            $index++;
            $itemAfterComma = false;
            while (true) {
                $space();
                if ($index >= $length) return $pending();
                if ($content[$index] === ']') {
                    if ($itemAfterComma) return null;
                    $index++; $completedGroups++;
                    break;
                }
                if ($content[$index] !== '{') return null;
                $start = $index;
                $stack = []; $quoted = false; $escaped = false;
                for (; $index < $length; $index++) {
                    $character = $content[$index];
                    if ($quoted) {
                        if ($escaped) $escaped = false;
                        elseif ($character === '\\') $escaped = true;
                        elseif ($character === '"') $quoted = false;
                        continue;
                    }
                    if ($character === '"') { $quoted = true; continue; }
                    if ($character === '[' || $character === '{') $stack[] = $character;
                    if (count($stack) > 32) return null;
                    if ($character === ']' || $character === '}') {
                        if (array_pop($stack) !== ($character === ']' ? '[' : '{')) return null;
                        if ($stack === []) break;
                    }
                }
                if ($index >= $length) return $pending();
                try { $item = json_decode(substr($content, $start, $index - $start + 1), true, 32, JSON_THROW_ON_ERROR); }
                catch (\Throwable $e) { return null; }
                $index++; $space();
                // A closing object alone is insufficient: wait for its legal array delimiter.
                if ($index >= $length) return $pending();
                if (!in_array($content[$index], [',', ']'], true)) return null;
                $groups[$group][] = $item;
                $itemAfterComma = $content[$index] === ',';
                if ($itemAfterComma) $index++;
            }
            $space(); $afterComma = false;
            if ($index >= $length) return $pending();
            if ($content[$index] === ',') { $index++; $afterComma = true; continue; }
            if ($content[$index] !== '}') return null;
        }
    }

    private static function reject(string $reason, ?string &$failure): ?array
    {
        $failure = $reason;
        return null;
    }

    private static function validate(array $data, array $snapshot, string $task, array $knownChart, ?string &$failure): ?array
    {
        if (!self::keys($data, self::GROUPS, self::GROUPS)) return self::reject('SCHEMA_INVALID', $failure);
        $sources = array_column($snapshot['sources'] ?? [], null, 'id');
        $output = [];
        foreach (self::GROUPS as $group) {
            if (!is_array($data[$group]) || !array_is_list($data[$group]) || count($data[$group]) > 6)
                return self::reject('SCHEMA_INVALID', $failure);
            if ($group === 'review' && $task !== 'live_review' && $data[$group] !== []) return self::reject('SCHEMA_INVALID', $failure);
            $output[$group] = [];
            foreach ($data[$group] as $item) {
                if (!is_array($item) || !self::keys($item, ['text', 'reason', 'evidence_ids'], ['text', 'evidence_ids'])
                    || !is_string($item['text']) || trim($item['text']) === ''
                    || mb_strlen($item['text']) > ($group === 'summary' ? 4000 : 600)
                    || (isset($item['reason']) && (!is_string($item['reason']) || mb_strlen($item['reason']) > 600))
                    || (array_key_exists('reason', $item) && $item['reason'] === null)
                    || !is_array($item['evidence_ids']) || !array_is_list($item['evidence_ids'])
                    || count($item['evidence_ids']) < 1 || count($item['evidence_ids']) > 8) return self::reject('SCHEMA_INVALID', $failure);
                $ids = [];
                foreach ($item['evidence_ids'] as $id) {
                    if (!is_string($id) || !isset($sources[$id]) || isset($ids[$id])) return self::reject('CITATION_INVALID', $failure);
                    $ids[$id] = true;
                }
                $text = $item['text'];
                if ($group === 'summary') {
                    if (count($ids) !== 1) return self::reject('CITATION_INVALID', $failure);
                    $source = $sources[$item['evidence_ids'][0]];
                    if (self::unsafeSourceQuote($text . "\n" . ($item['reason'] ?? ''))
                        || self::unsafeSourceQuote($source['text'])) return self::reject('SAFETY_REJECTED', $failure);
                    // Model summary prose/rationale never reaches the user. Reconstruct the entire
                    // quote from its validated ID, preserving denials, history and third-person scope.
                    if (($source['role'] ?? '') !== 'patient' || preg_match('/[？?]\s*$/u', $source['text']) === 1
                        || mb_strlen($source['text']) > 4000) continue;
                    $text = $source['text'];
                    unset($item['reason']);
                    $text = (self::LABELS[$source['role']] ?? self::LABELS['unknown']) . '：' . $text;
                } else {
                    if (self::unsafeGeneratedText($text . "\n" . ($item['reason'] ?? ''))) return self::reject('SAFETY_REJECTED', $failure);
                    $roles = array_unique(array_map(static fn (string $id): string => $sources[$id]['role'], $item['evidence_ids']));
                    if (!in_array('patient', $roles, true)) {
                        // Source identity is immutable. Never relabel a doctor's question as a patient fact.
                        if (self::unsupportedPatientPremise($text)) continue;
                        $item['reason'] = in_array('unknown', $roles, true)
                            ? '引用含说话人未确认的发言，仅供核实，不代表患者已确认。'
                            : '依据医生本次发言提出核实问题，不代表患者已确认。';
                    }
                    if ($group === 'questions') {
                        $text = trim($text);
                        if (preg_match('/[？?]/u', $text) !== 1) {
                            $candidate = preg_replace('/[。.!！\s]+$/u', '', $text) ?? $text;
                            if (preg_match('/(?:[吗呢么]$|^(?:是否|有无|有没有|请问|何时|怎么|什么|如何|哪些|哪里|什么时候))/u', $candidate) === 1)
                                $text = $candidate . '？';
                        }
                        if (preg_match('/^[^？?]+[？?]$/u', $text) !== 1) continue;
                    }
                    if ($group === 'checks' && preg_match('/^(核实|确认)/u', $text) !== 1) continue;
                    if (in_array($group, ['questions', 'checks'], true)
                        && self::reasksKnownDemographic($text, $item['evidence_ids'], $sources, $knownChart)) continue;
                }
                $output[$group][] = ['text' => $text, 'evidence_ids' => $item['evidence_ids']]
                    + (isset($item['reason']) && $item['reason'] !== '' ? ['reason' => $item['reason']] : []);
            }
            // Validate every supplied item before limiting presentation; hidden items cannot bypass safety.
            if ($group !== 'summary') $output[$group] = array_slice($output[$group], 0, 3);
        }
        return $output;
    }

    /** Narrow guard for explicit factual premises when no cited source belongs to the patient. */
    private static function unsupportedPatientPremise(string $text): bool
    {
        if (preg_match('/(?:患者|[您你])(?:本人)?(?:自述|表示|称|说|提到|否认)|患者(?:已|未|没有|一直|存在|出现|有)/u', $text) === 1)
            return true;
        if (preg_match('/是否|有无|有没有/u', $text) !== 1
            && preg_match('/(?:已|未|没有|从未|一直).{0,24}(?:多久|多长时间|何时|什么时候)|(?:为何|为什么).{0,16}(?:未|没有|一直)/u', $text) === 1)
            return true;
        $clauses = preg_split('/[，,。；;：:]/u', $text) ?: [];
        foreach ($clauses as $clause) {
            // A question about a state is not an assertion of that state. Chart references
            // are background, never patient confirmation; their full text stays in the prompt.
            if (preg_match('/[？?]|是否|有无|有没有|(?:病历|历史|既往)(?:中)?(?:记录|记载)/u', $clause) === 1) continue;
            if (preg_match('/(?:已(?:经)?|未(?:曾)?|没有|从未|一直|仍然|不再|否认)/u', $clause) === 1) return true;
        }
        return false;
    }

    /** Narrow demographic check: only a cited patient's explicit conflicting current value permits rechecking. */
    private static function reasksKnownDemographic(string $text, array $ids, array $sources, array $knownChart): bool
    {
        // Current chart demographics do not answer onset age, historical age or a relative's age.
        if (preg_match('/(?:发病|起病|患病|确诊|当时|那时|首次|第一次|开始出现|初次出现|绝经|停经|父亲|母亲|父母|孩子|儿子|女儿|家人|家属|配偶|丈夫|妻子)/u', $text) === 1)
            return false;
        $demographics = (string) ($knownChart['demographics'] ?? '');
        if (preg_match('/(?:年龄|年纪|岁数|几岁|多少岁|[您你](?:今年|现在)?多大(?:了)?[？?])/u', $text) === 1
            && preg_match('/(?<!\d)(\d{1,3})岁/u', $demographics, $age) === 1) {
            foreach ($ids as $id) {
                $source = $sources[$id];
                if ($source['role'] === 'patient' && preg_match('/^\s*(?:我(?:现在|今年)?|本人(?:现在|今年)?|今年)\s*(\d{1,3})\s*岁/u', $source['text'], $stated) === 1
                    && (int) $stated[1] !== (int) $age[1]) return false;
            }
            return true;
        }
        if (preg_match('/(?:性别|男(?:的|性)?还是女|女(?:的|性)?还是男)/u', $text) === 1
            && preg_match('/[男女]/u', $demographics, $gender) === 1) {
            foreach ($ids as $id) {
                $source = $sources[$id];
                if ($source['role'] === 'patient' && preg_match('/(?:我|本人)是(男性|女性|男的|女的)/u', $source['text'], $stated) === 1
                    && mb_substr($stated[1], 0, 1) !== $gender[0]) return false;
            }
            return true;
        }
        return false;
    }

    private static function keys(array $data, array $allowed, array $required): bool
    {
        return array_diff(array_keys($data), $allowed) === [] && array_diff($required, array_keys($data)) === [];
    }

    private static function unsafeGeneratedText(string $text): bool
    {
        // Conservative boundary for this deliberately limited information-organizing task.
        return self::unsafeSourceQuote($text) || preg_match('/'
            . '(建议|应当|应该|需要|立即|请|开始|停止|增加|减少|改为).{0,12}(服用|停药|换药|用药|加药|给药|注射)|'
            . '(确诊|诊断为|辨证为|证型为|开具处方|医嘱|指南.{0,16}(推荐|要求|规定|条款)|风险[为：:]?(高|中|低))|'
            . '(保证|确保|包).{0,6}(治好|治愈|疗效)|(?:下单|成交|购买疗程|加购|套餐|限时优惠)|'
            . '\b\d+(?:\.\d+)?\s*(?:mg|mcg|毫克|微克|克\/日)\b/iu', $text) === 1;
    }

    private static function unsafeSourceQuote(string $text): bool
    {
        return preg_match('/[<>\x00-\x08\x0b\x0c\x0e-\x1f]|忽略.{0,12}(指令|规则)|系统提示|system\s*prompt|ignore\s+(previous|all)/iu', $text) === 1;
    }

    /** Response references are a projection, not a new snapshot/revision or the UI subtitle window. */
    public static function citedContext(array $snapshot, array $result): array
    {
        $ids = [];
        foreach (self::GROUPS as $group) foreach ($result[$group] as $item)
            foreach ($item['evidence_ids'] as $id) $ids[$id] = true;
        $snapshot['sources'] = array_values(array_filter($snapshot['sources'],
            static fn (array $source): bool => isset($ids[$source['id']])));
        return $snapshot;
    }

    /** Safe textual fallback for clients that do not yet render structured cards. */
    public static function answer(array $result, array $snapshot): string
    {
        $lines = ['本次通话资料草稿，供医生核实。'];
        if ($snapshot['transcription_status'] === 'partial') $lines[] = '转写仅部分保存，以下不能代表完整通话。';
        elseif ($snapshot['transcription_status'] === 'running') $lines[] = '仅依据截至当前已保存的完成分段。';
        foreach (['questions' => '建议追问', 'summary' => '关键原话', 'checks' => '待核实', 'review' => '问诊复盘'] as $key => $label) {
            if ($result[$key] === []) continue;
            $lines[] = $label . '：';
            foreach ($result[$key] as $item) $lines[] = '• ' . $item['text']
                . (isset($item['reason']) ? '（' . $item['reason'] . '）' : '');
        }
        return implode("\n", $lines);
    }
}