<?php

namespace App\Console\Commands;

use App\Jobs\GenerateAnalysisPdfJob;
use App\Jobs\ProcessExamAnswerAnalysisJob;
use App\Services\TaskManager;
use Carbon\Carbon;
use Illuminate\Console\Command;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Log;
use Throwable;

class BackfillExamAnalysisResultsCommand extends Command
{
    private const ACTION_SKIP = 'skip';
    private const ACTION_ANALYSIS = 'analysis';
    private const ACTION_PDF_ONLY = 'pdf_only';
    private const ACTION_SYNC_PDF_URL = 'sync_pdf_url';

    protected $signature = 'exam:backfill-analysis-results
                            {--since= : papers.completed_at >= 该时间（默认今天 00:00:00）}
                            {--paper= : 仅处理指定 paper_id}
                            {--student= : 仅处理指定 student_id}
                            {--limit=100 : 最多处理多少条候选试卷}
                            {--dry-run : 只打印待回填列表，不执行回填}';

    protected $description = '回填 exam_analysis_results 缺失分析数据或缺失 PDF URL 的试卷';

    public function handle(TaskManager $taskManager): int
    {
        $sinceRaw = (string) ($this->option('since') ?: Carbon::today()->toDateTimeString());
        try {
            $since = Carbon::parse($sinceRaw);
        } catch (Throwable) {
            $this->error('无效的 --since 时间：'.$sinceRaw);

            return self::FAILURE;
        }

        $limit = max(1, (int) $this->option('limit'));
        $paperFilter = $this->option('paper');
        $studentFilter = $this->option('student');
        $isDryRun = (bool) $this->option('dry-run');

        $paperRows = DB::connection('mysql')
            ->table('papers')
            ->whereNotNull('completed_at')
            ->where('completed_at', '>=', $since->toDateTimeString())
            ->whereNotNull('student_id')
            ->where('student_id', '!=', '')
            ->when($paperFilter, fn ($q) => $q->where('paper_id', $paperFilter))
            ->when($studentFilter, fn ($q) => $q->where('student_id', $studentFilter))
            ->orderBy('completed_at')
            ->limit($limit)
            ->get(['paper_id', 'student_id', 'completed_at']);

        $targets = [];
        $counts = [
            self::ACTION_SKIP => 0,
            self::ACTION_ANALYSIS => 0,
            self::ACTION_PDF_ONLY => 0,
            self::ACTION_SYNC_PDF_URL => 0,
        ];

        foreach ($paperRows as $paper) {
            $latest = DB::connection('mysql')
                ->table('exam_analysis_results')
                ->where('paper_id', $paper->paper_id)
                ->where('student_id', $paper->student_id)
                ->orderByDesc('created_at')
                ->first(['id', 'analysis_data', 'analysis_pdf_url']);

            $studentReportPdfUrl = DB::connection('mysql')
                ->table('student_reports')
                ->where('paper_id', $paper->paper_id)
                ->where('student_id', $paper->student_id)
                ->where('report_type', 'exam_analysis')
                ->whereNotNull('pdf_url')
                ->where('pdf_url', '!=', '')
                ->orderByDesc('updated_at')
                ->value('pdf_url');

            $action = $this->resolveBackfillAction(
                $latest->analysis_data ?? null,
                $latest->id ?? null,
                $latest->analysis_pdf_url ?? null,
                $studentReportPdfUrl
            );

            $counts[$action]++;
            if ($action === self::ACTION_SKIP) {
                continue;
            }

            $targets[] = (object) [
                'paper_id' => (string) $paper->paper_id,
                'student_id' => (string) $paper->student_id,
                'completed_at' => (string) $paper->completed_at,
                'action' => $action,
                'analysis_id' => $latest->id ?? null,
                'student_report_pdf_url' => $studentReportPdfUrl,
            ];
        }

        $this->info(sprintf(
            '扫描完成：已完成试卷 %d 条，需补分析 %d 条，仅补PDF %d 条，同步PDF URL %d 条，已跳过 %d 条（since=%s, limit=%d）',
            $paperRows->count(),
            $counts[self::ACTION_ANALYSIS],
            $counts[self::ACTION_PDF_ONLY],
            $counts[self::ACTION_SYNC_PDF_URL],
            $counts[self::ACTION_SKIP],
            $since->toDateTimeString(),
            $limit
        ));

        if ($isDryRun) {
            foreach ($targets as $item) {
                $this->line(sprintf(
                    '[dry-run] action=%s paper_id=%s student_id=%s completed_at=%s analysis_id=%s',
                    $item->action,
                    $item->paper_id,
                    $item->student_id,
                    $item->completed_at,
                    $item->analysis_id ?? 'null'
                ));
            }

            return self::SUCCESS;
        }

        $ok = 0;
        $failed = 0;
        foreach ($targets as $item) {
            try {
                if ($item->action === self::ACTION_ANALYSIS) {
                    $questions = $this->buildQuestionsFromPaperQuestions($item->paper_id);
                    if ($questions === []) {
                        $this->warn("回填失败：{$item->paper_id} 无可用 paper_questions");
                        $failed++;
                        continue;
                    }

                    $examData = [
                        'paper_id' => $item->paper_id,
                        'student_id' => $item->student_id,
                        'questions' => $questions,
                        'force_recalculate' => true,
                    ];

                    $taskId = $taskManager->createTask(TaskManager::TASK_TYPE_ANALYSIS, [
                        'type' => 'exam_answer_analysis_backfill',
                        'paper_id' => $item->paper_id,
                        'student_id' => $item->student_id,
                        'question_count' => count($questions),
                    ]);

                    dispatch(new ProcessExamAnswerAnalysisJob($taskId, $examData));
                    $this->info("已投递补分析任务：{$item->paper_id} / {$item->student_id} task_id={$taskId}");
                    $ok++;
                    continue;
                }

                if ($item->action === self::ACTION_SYNC_PDF_URL) {
                    DB::connection('mysql')
                        ->table('exam_analysis_results')
                        ->where('id', $item->analysis_id)
                        ->update([
                            'analysis_pdf_url' => $item->student_report_pdf_url,
                            'updated_at' => now(),
                        ]);

                    $this->info("已同步PDF URL：{$item->paper_id} / {$item->student_id}");
                    $ok++;
                    continue;
                }

                dispatch(new GenerateAnalysisPdfJob(
                    $item->paper_id,
                    $item->student_id,
                    null
                ));
                $this->info("已投递补PDF任务：{$item->paper_id} / {$item->student_id}");
                $ok++;
            } catch (Throwable $e) {
                $this->error("回填失败：{$item->paper_id} / {$item->student_id} -> ".$e->getMessage());
                Log::error('BackfillExamAnalysisResultsCommand: 回填失败', [
                    'paper_id' => $item->paper_id,
                    'student_id' => $item->student_id,
                    'action' => $item->action,
                    'error' => $e->getMessage(),
                    'exception' => get_class($e),
                ]);
                $failed++;
            }
        }

        $this->info("回填投递完成：成功 {$ok}，失败 {$failed}");

        return $failed > 0 ? self::FAILURE : self::SUCCESS;
    }

    private function resolveBackfillAction(
        mixed $analysisDataRaw,
        mixed $analysisId,
        mixed $analysisPdfUrl,
        mixed $studentReportPdfUrl
    ): string
    {
        $hasValidAnalysis = $this->hasValidAnalysisData($analysisDataRaw, $analysisId);
        $hasAnalysisPdf = $this->hasNonEmptyString($analysisPdfUrl);
        $hasStudentReportPdf = $this->hasNonEmptyString($studentReportPdfUrl);

        if (! $hasValidAnalysis) {
            return self::ACTION_ANALYSIS;
        }

        if ($hasAnalysisPdf) {
            return self::ACTION_SKIP;
        }

        return $hasStudentReportPdf ? self::ACTION_SYNC_PDF_URL : self::ACTION_PDF_ONLY;
    }

    private function hasValidAnalysisData(mixed $analysisDataRaw, mixed $analysisId): bool
    {
        if ($analysisId === null || $analysisDataRaw === null) {
            return false;
        }

        $raw = is_string($analysisDataRaw) ? trim($analysisDataRaw) : '';
        if ($raw === '') {
            return false;
        }

        $decoded = json_decode($raw, true);
        if (! is_array($decoded)) {
            return false;
        }

        $hasQuestionAnalysis = isset($decoded['question_analysis']) && is_array($decoded['question_analysis']) && $decoded['question_analysis'] !== [];
        $hasOverallSummary = isset($decoded['overall_summary']) && is_array($decoded['overall_summary']) && $decoded['overall_summary'] !== [];

        return $hasQuestionAnalysis || $hasOverallSummary;
    }

    private function hasNonEmptyString(mixed $value): bool
    {
        return is_string($value) && trim($value) !== '';
    }

    /**
     * @return list<array<string, mixed>>
     */
    private function buildQuestionsFromPaperQuestions(string $paperId): array
    {
        $rows = DB::connection('mysql')
            ->table('paper_questions')
            ->where('paper_id', $paperId)
            ->orderBy('question_number')
            ->get([
                'question_id',
                'question_bank_id',
                'score',
                'score_obtained',
                'student_answer',
                'is_correct',
                'teacher_comment',
            ]);

        $questions = [];
        foreach ($rows as $row) {
            $qid = $row->question_bank_id ?? $row->question_id ?? null;
            if ($qid === null || $qid === '') {
                continue;
            }

            $item = [
                'question_id' => (string) $qid,
                'score' => isset($row->score) ? (float) $row->score : 2.0,
                'is_correct' => $this->normalizeIsCorrect($row->is_correct),
                'student_answer' => $row->student_answer,
                'teacher_comment' => $row->teacher_comment,
            ];

            if ($row->score_obtained !== null) {
                $item['score_obtained'] = (float) $row->score_obtained;
            }

            $questions[] = $item;
        }

        return $questions;
    }

    /**
     * @return list<int>
     */
    private function normalizeIsCorrect(mixed $value): array
    {
        if (is_array($value)) {
            return $this->flattenToBinary($value);
        }

        if (is_string($value)) {
            $trimmed = trim($value);
            if ($trimmed !== '' && ($trimmed[0] === '[' || $trimmed[0] === '{')) {
                $decoded = json_decode($trimmed, true);
                if (is_array($decoded)) {
                    return $this->flattenToBinary($decoded);
                }
            }
        }

        if ($value === null || $value === '') {
            return [0];
        }

        return [((bool) $value) ? 1 : 0];
    }

    /**
     * @param  array<int, mixed>  $values
     * @return list<int>
     */
    private function flattenToBinary(array $values): array
    {
        $out = [];
        foreach ($values as $v) {
            $out[] = ((bool) $v) ? 1 : 0;
        }

        return $out === [] ? [0] : $out;
    }
}