<?php

namespace App\Http\Controllers\Api\Admin;

use App\Http\Controllers\Controller;
use App\Models\Application;
use App\Models\ApplicationReviewScore;
use App\Models\Competition;
use App\Models\ReviewerScope;
use App\Support\SignupOptionCatalog;
use App\Support\PortalLocale;
use Illuminate\Http\JsonResponse;
use Illuminate\Support\Facades\DB;

class ManageReportController extends Controller
{
    public function show(Competition $competition): JsonResponse
    {
        $competition->loadMissing('tracks');

        $apps = Application::query()
            ->where('competition_id', $competition->id)
            ->where('status', 'submitted')
            ->get();

        $eligibleApps = $apps->filter(fn (Application $a) => $a->isReviewEligible())->values();

        $appIds = $apps->pluck('id')->map(fn ($id) => (int) $id)->all();
        $reviewStats = $this->reviewStatsForApplicationIds($appIds);
        $reviewerCountsByTrack = ReviewerScope::query()
            ->select('track_code', DB::raw('COUNT(*) as total'))
            ->where('competition_id', $competition->id)
            ->groupBy('track_code')
            ->pluck('total', 'track_code');

        $trackTitles = $competition->tracks->pluck('title', 'track_code');

        $total = $apps->count();
        $passed = $apps->where('review_result', 'passed')->count();
        $rejected = $apps->where('review_result', 'rejected')->count();
        $reviewedCount = 0;
        $eligibleReviewedCount = 0;

        foreach ($apps as $app) {
            $trackCode = (string) ($app->track ?? '');
            $required = (int) ($reviewerCountsByTrack[$trackCode] ?? 0);
            $completed = (int) ($reviewStats[(int) $app->id]['submitted_review_count'] ?? 0);
            // 已评审：该项目所属赛道评委均已提交；跨全部赛道汇总
            if ($required > 0 && $completed >= $required) {
                $reviewedCount += 1;
                if ($app->isReviewEligible()) {
                    $eligibleReviewedCount += 1;
                }
            }
        }

        // 待评审 = 参与评审的项目数 − 其中已评审完成数（不含不参与评审）
        $pendingReview = max(0, $eligibleApps->count() - $eligibleReviewedCount);

        $passRate = $total > 0 ? round(($passed / $total) * 100, 1) : 0.0;
        $locationCounts = $this->eventLocationCounts($apps);

        return response()->json([
            'kpis' => [
                ['label' => '项目总数', 'value' => $total, 'sub' => '已提交的有效项目数', 'type' => 'total'],
                ...$locationCounts,
                ['label' => '待评审数量', 'value' => $pendingReview, 'sub' => '参与评审项目中尚未评审完成的数量'],
                ['label' => '通过率', 'value' => $passRate.'%', 'sub' => '已通过 / 总项目'],
            ],
            'track_counts' => $this->countEntries($apps, fn (Application $a) => $trackTitles->get($a->track ?? '') ?? ($a->track ?? '未填写')),
            'degree_counts' => $this->countEntries($apps, fn (Application $a) => trim((string) ($a->degree ?? '')) ?: '未填写'),
            'country_counts' => $this->countEntries($apps, fn (Application $a) => trim((string) ($a->location_country ?? '')) ?: '未填写'),
            'province_counts' => $this->countEntries(
                $apps->filter(fn (Application $a) => trim((string) ($a->location_country ?? '')) === '中国'),
                fn (Application $a) => trim((string) ($a->location_province ?? '')) ?: '未填写',
                6,
            ),
            'school_top' => $this->topGroups($apps, fn (Application $a) => trim((string) ($a->school ?? '')) ?: '未填写'),
            'city_top' => $this->topGroups($apps, fn (Application $a) => $this->cityLabel($a)),
            'track_score_rank' => $this->trackScoreRank($apps, $reviewStats, $trackTitles, $reviewerCountsByTrack),
            'track_top_projects' => $this->trackTopProjects($apps, $reviewStats, $trackTitles, $reviewerCountsByTrack),
            'summary' => [
                'total' => $total,
                'passed' => $passed,
                'rejected' => $rejected,
                'pending_review' => $pendingReview,
                'reviewed' => $eligibleReviewedCount,
            ],
        ]);
    }

    /**
     * @param  list<int>  $ids
     * @return array<int, array{submitted_review_count: int, team_avg: float|null}>
     */
    private function reviewStatsForApplicationIds(array $ids): array
    {
        if (count($ids) === 0) {
            return [];
        }

        return ApplicationReviewScore::query()
            ->select([
                'application_id',
                DB::raw('COUNT(*) as submitted_review_count'),
                DB::raw('AVG(line_total) as team_avg'),
            ])
            ->whereIn('application_id', $ids)
            ->groupBy('application_id')
            ->get()
            ->mapWithKeys(fn ($row) => [
                (int) $row->application_id => [
                    'submitted_review_count' => (int) $row->submitted_review_count,
                    'team_avg' => $row->team_avg !== null ? (float) $row->team_avg : null,
                ],
            ])
            ->all();
    }

    /**
     * @param  \Illuminate\Support\Collection<int, Application>  $apps
     * @return list<array{label: string, value: int, sub: string, type: string}>
     */
    private function eventLocationCounts($apps): array
    {
        $counts = [];
        foreach ($apps as $app) {
            $code = trim((string) ($app->event_location ?? ''));
            if ($code === '') {
                continue;
            }
            $counts[$code] = ($counts[$code] ?? 0) + 1;
        }

        $cards = [];
        foreach (SignupOptionCatalog::eventLocations() as $code => $labels) {
            $label = (string) ($labels[PortalLocale::ZH] ?? $code);
            $title = str_contains($label, '赛区') ? $label : $label.'赛区';
            $cards[] = [
                'label' => $title.'报名',
                'value' => (int) ($counts[$code] ?? 0),
                'sub' => '按意向参赛地点统计',
                'type' => 'session',
            ];
        }

        return $cards;
    }

    /**
     * @param  \Illuminate\Support\Collection<int, Application>  $apps
     * @return list<array{label: string, count: int, percent: float}>
     */
    private function countEntries($apps, callable $keyGetter, ?int $limit = null): array
    {
        $counts = [];
        foreach ($apps as $app) {
            $key = (string) $keyGetter($app);
            $counts[$key] = ($counts[$key] ?? 0) + 1;
        }
        arsort($counts);
        if ($limit !== null) {
            $counts = array_slice($counts, 0, $limit, true);
        }
        $total = max(1, $apps->count());

        return collect($counts)->map(fn ($count, $label) => [
            'label' => (string) $label,
            'count' => (int) $count,
            'percent' => round(((int) $count / $total) * 100, 1),
        ])->values()->all();
    }

    /**
     * @param  \Illuminate\Support\Collection<int, Application>  $apps
     * @return list<array{rank: int, name: string, total: int, pass_rate: string}>
     */
    private function topGroups($apps, callable $keyGetter, int $limit = 5): array
    {
        $groups = [];
        foreach ($apps as $app) {
            $key = (string) $keyGetter($app);
            if (! isset($groups[$key])) {
                $groups[$key] = ['total' => 0, 'pass' => 0];
            }
            $groups[$key]['total'] += 1;
            if ($app->review_result === 'passed') {
                $groups[$key]['pass'] += 1;
            }
        }
        uasort($groups, fn ($a, $b) => $b['total'] <=> $a['total']);
        $top = array_slice($groups, 0, $limit, true);
        $rank = 1;
        $rows = [];
        foreach ($top as $name => $v) {
            $rate = $v['total'] > 0 ? round(($v['pass'] / $v['total']) * 100, 1).'%' : '-';
            $rows[] = ['rank' => $rank++, 'name' => $name, 'total' => $v['total'], 'pass_rate' => $rate];
        }

        return $rows;
    }

    private function cityLabel(Application $app): string
    {
        if (trim((string) ($app->location_country ?? '')) === '海外') {
            return trim((string) ($app->oversea_country ?? '')) ?: '海外';
        }

        return trim((string) ($app->location_city ?? '')) ?: '未填写';
    }

    /**
     * @param  \Illuminate\Support\Collection<int, Application>  $apps
     * @param  array<int, array{submitted_review_count: int, team_avg: float|null}>  $reviewStats
     * @param  \Illuminate\Support\Collection<string, string>  $trackTitles
     * @param  \Illuminate\Support\Collection<string, int>  $reviewerCountsByTrack
     * @return list<array{rank: int, track: string, avg: float, count: int}>
     */
    private function trackScoreRank($apps, array $reviewStats, $trackTitles, $reviewerCountsByTrack): array
    {
        $groups = [];
        foreach ($apps as $app) {
            $avg = $this->completedAvg($app, $reviewStats, $reviewerCountsByTrack);
            if ($avg === null) {
                continue;
            }
            $track = $trackTitles->get($app->track ?? '') ?? ($app->track ?? '未填写');
            $groups[$track][] = $avg;
        }
        $rows = [];
        foreach ($groups as $track => $avgs) {
            $rows[] = [
                'track' => $track,
                'avg' => round(array_sum($avgs) / count($avgs), 2),
                'count' => count($avgs),
            ];
        }
        usort($rows, fn ($a, $b) => $b['avg'] <=> $a['avg']);

        return array_map(fn ($row, $idx) => $row + ['rank' => $idx + 1], $rows, array_keys($rows));
    }

    /**
     * @param  \Illuminate\Support\Collection<int, Application>  $apps
     * @return list<array{track: string, items: list<array{rank: int, name: string, avg: float}>}>
     */
    private function trackTopProjects($apps, array $reviewStats, $trackTitles, $reviewerCountsByTrack): array
    {
        $byTrack = [];
        foreach ($apps as $app) {
            $avg = $this->completedAvg($app, $reviewStats, $reviewerCountsByTrack);
            if ($avg === null) {
                continue;
            }
            $track = $trackTitles->get($app->track ?? '') ?? ($app->track ?? '未填写');
            $byTrack[$track][] = [
                'name' => trim((string) ($app->project_name ?? '')) ?: ('项目 #'.$app->id),
                'avg' => $avg,
            ];
        }
        ksort($byTrack);
        $result = [];
        foreach ($byTrack as $track => $items) {
            usort($items, fn ($a, $b) => $b['avg'] <=> $a['avg']);
            $result[] = [
                'track' => $track,
                'items' => array_map(
                    fn ($item, $idx) => ['rank' => $idx + 1, 'name' => $item['name'], 'avg' => round($item['avg'], 2)],
                    array_slice($items, 0, 3),
                    array_keys(array_slice($items, 0, 3)),
                ),
            ];
        }

        return $result;
    }

    /**
     * @param  array<int, array{submitted_review_count: int, team_avg: float|null}>  $reviewStats
     * @param  \Illuminate\Support\Collection<string, int>  $reviewerCountsByTrack
     */
    private function completedAvg(Application $app, array $reviewStats, $reviewerCountsByTrack): ?float
    {
        $trackCode = (string) ($app->track ?? '');
        $required = (int) ($reviewerCountsByTrack[$trackCode] ?? 0);
        $stats = $reviewStats[(int) $app->id] ?? null;
        $completed = (int) ($stats['submitted_review_count'] ?? 0);
        if ($required <= 0 || $completed < $required) {
            return null;
        }

        return $stats['team_avg'] ?? null;
    }
}