<?php

declare(strict_types=1);

namespace app\adminapi\service;

/** Validate complete prose units before exposing their original bytes to clients. */
final class TcmClinicalReportStream
{
    /**
     * 互联网面诊只有舌象等部分资料，校验规则命中时不再截断回答：
     * 原文照常交付，问题码记入 warnings() 供医师复核。设为 true 恢复拦截模式。
     */
    public const BLOCKING = false;

    private string $pending = '';
    private string $accepted = '';
    private bool $stopped = false;
    private array $issues = [];
    private array $warnings = [];
    private \Closure $forward;
    private ?\Closure $onReject;
    private string $deferred = '';
    private bool $holdingFinal = false;
    private ?\Closure $shouldAbort;
    private ?array $finalContract = null;
    private array $priorAnswerUnits = [];

    public function __construct(private array $ledger, callable $forward, ?callable $onReject = null,
        string $validatedPrefix = '', private ?string $continuationQuery = null,
        private ?array $evidenceIndex = null, private ?string $finalCheckpointQuery = null,
        ?callable $shouldAbort = null, private bool $pulseExcluded = false, bool $preventPrefixRepeat = false)
    {
        // Context from a previous, already delivered attempt is validated with
        // every new unit, but is never sent through forward a second time.
        $this->accepted = $validatedPrefix;
        $this->forward = \Closure::fromCallable($forward);
        $this->onReject = $onReject === null ? null : \Closure::fromCallable($onReject);
        $this->shouldAbort = $shouldAbort === null ? null : \Closure::fromCallable($shouldAbort);
        if ($preventPrefixRepeat) {
            $this->priorAnswerUnits = array_values(array_filter(array_map('trim',
                preg_split('/(?:\r?\n){2}/', $validatedPrefix) ?: []), static fn (string $unit): bool => $unit !== ''));
        }
    }

    public function push(string $delta): bool
    {
        if ($this->stopped) return false;
        if ($this->finalCheckpointQuery !== null && $this->shouldAbort !== null && ($this->shouldAbort)()) {
            $this->stopped = true;
            return false;
        }
        $this->pending .= $delta;
        if (strlen($this->accepted) + strlen($this->deferred) + strlen($this->pending) > 100000) {
            $this->issues = [['code' => 'REPORT_BOUND_EXCEEDED', 'source_id' => 'report']];
            $this->stopped = true;
            return false;
        }
        // A token prefix is not a complete claim. Do not release it before its
        // containing paragraph is available for the source-state check.
        while (preg_match('/(?:\r?\n){2}/', $this->pending, $boundary, PREG_OFFSET_CAPTURE) === 1) {
            $end = $boundary[0][1] + strlen($boundary[0][0]);
            $unit = substr($this->pending, 0, $end);
            $this->pending = substr($this->pending, $end);
            if (!$this->release($unit)) return false;
        }
        return true;
    }

    public function finish(): bool
    {
        if ($this->stopped) return false;
        $unit = $this->pending;
        $this->pending = '';
        if (!$this->release($unit)) return false;
        if ($this->finalCheckpointQuery === null) return true;
        $candidate = $this->accepted . $this->deferred;
        $review = $this->review($candidate, true);
        if (empty($review['valid']) && !$this->reject($this->deferred, $review['issues'])) return false;
        $this->finalContract = TcmLongReportContract::validate($candidate, $this->finalCheckpointQuery);
        if (empty($this->finalContract['valid'])
            && !$this->reject($this->deferred, [['code' => 'REPORT_FINAL_CONTRACT_INVALID', 'source_id' => 'report']])) {
            return false;
        }
        if ($this->shouldAbort !== null && ($this->shouldAbort)()) { $this->stopped = true; return false; }
        if ($this->deferred === '') return true;
        // This is exactly the original, never-delivered model tail. No repair,
        // trimming, padding or local composition is permitted at this boundary.
        if (($this->forward)($this->deferred) === false) { $this->stopped = true; return false; }
        $this->accepted .= $this->deferred;
        $this->deferred = '';
        return true;
    }

    public function rejected(): bool { return $this->issues !== []; }
    public function issues(): array { return $this->issues; }
    public function warnings(): array { return $this->warnings; }
    public function acceptedContent(): string { return $this->accepted; }
    public function finalContract(): ?array { return $this->finalContract; }

    private function release(string $unit): bool
    {
        if ($unit === '') return true;
        if (in_array(trim($unit), $this->priorAnswerUnits, true) && !$this->isOrdinaryHeadingUnit($unit)
            && !$this->reject($unit, [['code' => 'REPORT_CONTINUATION_REPEATED_SECTION', 'source_id' => 'report']])) {
            return false;
        }
        if ($this->finalCheckpointQuery !== null && !$this->holdingFinal) {
            $offset = 0;
            foreach (preg_split('/(?<=\n)|(?<=\r)(?!\n)/', $unit) ?: [] as $line) {
                $shape = TcmLongReportContract::validate($line, $this->finalCheckpointQuery);
                if (in_array(6, $shape['section_order'], true)) {
                    if ($offset > 0 && !$this->release(substr($unit, 0, $offset))) return false;
                    $unit = substr($unit, $offset);
                    $this->holdingFinal = true;
                    break;
                }
                $offset += strlen($line);
            }
        }
        if ($this->holdingFinal) {
            $this->deferred .= $unit;
            $review = $this->review($this->accepted . $this->deferred);
            return !empty($review['valid']) || $this->reject($this->deferred, $review['issues']);
        }
        $candidate = $this->accepted . $unit;
        $review = $this->review($candidate);
        if (empty($review['valid']) && !$this->reject($unit, $review['issues'])) return false;
        if (($this->forward)($unit) === false) {
            $this->stopped = true;
            return false;
        }
        $this->accepted .= $unit;
        return true;
    }

    private function isOrdinaryHeadingUnit(string $unit): bool
    {
        // Ordinary answers may retain a repeated explicit Markdown heading.
        // Skip only duplicate detection: clinical review and raw forwarding
        // below still apply. Long-report continuations remain strict.
        if ($this->continuationQuery !== null || $this->finalCheckpointQuery !== null) return false;
        if (preg_match('/\A {0,3}#{1,6}[ \t]+([^\r\n]+)(?:\r?\n){0,2}\z/u', $unit, $heading) !== 1) return false;
        return preg_match('/[^ \t#]/u', $heading[1]) === 1;
    }

    private function review(string $candidate, bool $complete = false): array
    {
        $review = $this->pulseExcluded
            ? TcmConsultationPulsePolicy::validate($this->ledger, $candidate) : ['valid' => true];
        if (!empty($review['valid'])) $review = TcmClinicalFactStateGuard::validate($this->ledger, $candidate);
        if (!empty($review['valid']) && $this->evidenceIndex !== null) {
            $review = TcmClinicalEvidenceContract::validate($this->evidenceIndex, $candidate, $complete);
        }
        if (!empty($review['valid']) && $this->continuationQuery !== null) {
            $shape = TcmLongReportContract::validate($candidate, $this->continuationQuery);
            if (in_array('DUPLICATE_REPORT_SECTION', array_column($shape['issues'], 'code'), true)) {
                $review = ['valid' => false, 'issues' => [
                    ['code' => 'REPORT_CONTINUATION_REPEATED_SECTION', 'source_id' => 'report'],
                ]];
            }
        }
        if (!empty($review['valid']) && $this->finalCheckpointQuery !== null) {
            $review = TcmHerbalPremiseGuard::validate($candidate, $this->ledger);
        }
        return $review;
    }

    private function reject(string $unit, array $issues): bool
    {
        if (!self::BLOCKING) {
            // 非拦截模式：只记录问题码，调用方继续按原流程交付该段原文。
            foreach ($issues as $issue) {
                if (!is_array($issue)) continue;
                $key = ($issue['code'] ?? '') . '|' . ($issue['source_id'] ?? '');
                if (!isset($this->warnings[$key]) && count($this->warnings) < 32) $this->warnings[$key] = $issue;
            }
            return true;
        }
        if ($this->holdingFinal) {
            $issues[] = ['code' => 'REPORT_FINAL_SECTION_UNDELIVERED', 'source_id' => 'report'];
        }
        $this->issues = $issues;
        $this->stopped = true;
        if ($this->onReject !== null) ($this->onReject)($unit, $this->issues);
        return false;
    }
}