<?php

namespace App\Services;

use App\Models\Entry;
use App\Models\ScoreSheet;
use App\Models\ScoringGuide;
use Illuminate\Support\Collection;
use Illuminate\Support\Facades\Cache;
use Illuminate\Support\Facades\DB;

use function array_unshift;

class ScoreService
{
    protected $auditionCache;

    protected $entryCache;

    /**
     * Create a new class instance.
     */
    public function __construct(AuditionCacheService $auditionCache, EntryCacheService $entryCache)
    {
        $this->auditionCache = $auditionCache;
        $this->entryCache = $entryCache;
    }

    /**
     * Cache all scoring guides
     */
    public function getScoringGuides(): \Illuminate\Database\Eloquent\Collection
    {
        $cacheKey = 'scoringGuides';

        return Cache::remember($cacheKey, 3600, fn () => ScoringGuide::with('subscores')->withCount('subscores')->get());
    }

    /**
     * Retrieve a single scoring guide from the cache
     */
    public function getScoringGuide($id): ScoringGuide
    {
        return $this->getScoringGuides()->find($id);
    }

    /**
     * Clear the scoring guide cache
     */
    public function clearScoringGuideCache(): void
    {
        Cache::forget('scoringGuides');
    }

    /**
     * Returns an array where each key is an entry id and the value is the number
     * of score sheets assigned to that entry.
     *
     * @return Collection
     */
    public function entryScoreSheetCounts()
    {
        $cacheKey = 'entryScoreSheetCounts';

        return Cache::remember($cacheKey, 10, function () {
            // For each Entry get the number of ScoreSheets associated with it
            $scoreSheetCountsByEntry = ScoreSheet::select('entry_id', DB::raw('count(*) as count'))
                ->groupBy('entry_id')
                ->get()
                ->pluck('count', 'entry_id');

            $entryScoreSheetCounts = [];
            $entries = $this->entryCache->getAllEntries();
            foreach ($entries as $entry) {
                $entryScoreSheetCounts[$entry->id] = $scoreSheetCountsByEntry[$entry->id] ?? 0;
            }

            return $entryScoreSheetCounts;

        });

    }

    /**
     * Get final scores array for the requested entry. The first element is the total score. The following elements are sums
     * of each subscore in tiebreaker order
     *
     * @return array
     */
    public function entryTotalScores(Entry $entry)
    {
        $cacheKey = 'entry'.$entry->id.'totalScores';

        return Cache::remember($cacheKey, 3600, function () use ($entry) {
            return $this->calculateFinalScoreArray($entry->audition->scoring_guide_id, $entry->scoreSheets);
        });
    }

    /**
     * Calculate and cache scores for all entries for the provided audition ID
     *
     * @return void
     */
    public function calculateScoresForAudition($auditionId)
    {
        static $alreadyChecked = [];
        // if $auditionId is in the array $alreadyChecked return
        if (in_array($auditionId, $alreadyChecked)) {
            return;
        }
        $alreadyChecked[] = $auditionId;
        $audition = $this->auditionCache->getAudition($auditionId);
        $scoringGuideId = $audition->scoring_guide_id;
        $entries = $this->entryCache->getEntriesForAudition($auditionId);
        $entries->load('scoreSheets'); // TODO Cache this somehow, it's expensive and repetitive on the seating page

        foreach ($entries as $entry) {
            $cacheKey = 'entry'.$entry->id.'totalScores';
            if (Cache::has($cacheKey)) {
                continue;
            }
            $thisTotalScore = $this->calculateFinalScoreArray($scoringGuideId, $entry->scoreSheets);
            Cache::put($cacheKey, $thisTotalScore, 3600);
        }
    }

    public function clearScoreSheetCountCache()
    {
        $cacheKey = 'entryScoreSheetCounts';
        Cache::forget($cacheKey);
    }

    public function clearEntryTotalScoresCache($entryId)
    {
        $cacheKey = 'entry'.$entryId.'totalScores';
        Cache::forget($cacheKey);
    }

    public function clearAllCachedTotalScores()
    {
        foreach ($this->entryCache->getAllEntries() as $entry) {
            $cacheKey = 'entry'.$entry->id.'totalScores';
            Cache::forget($cacheKey);
        }
    }

    /**
     * Calculate final score using the provided scoring guide and score sheets. Returns an array of scores
     * The first element is the total score. The following elements are the sum of each subscore
     * in tiebreaker order.
     */
    public function calculateFinalScoreArray($scoringGuideId, array|Collection $scoreSheets): array
    {

        $sg = $this->getScoringGuide($scoringGuideId);

        // TODO cache the scoring guides with their subscores
        $subscores = $sg->subscores->sortBy('tiebreak_order');

        $ignoredSubscores = []; // This will be subscores not used for seating

        // Init final scores array
        $finalScoresArray = [];
        foreach ($subscores as $subscore) {
            if (! $subscore->for_seating) { // Ignore scores that are not for seating
                $ignoredSubscores[] = $subscore->id;

                continue;
            }
            $finalScoresArray[$subscore->id] = 0;
        }

        foreach ($scoreSheets as $sheet) {
            foreach ($sheet->subscores as $ss) {
                if (in_array($ss['subscore_id'], $ignoredSubscores)) {  // Ignore scores that are not for seating
                    continue;
                }
                $finalScoresArray[$ss['subscore_id']] += $ss['score'];
            }
        }

        // calculate weighted final score
        $totalScore = 0;
        $totalWeight = 0;
        foreach ($subscores as $subscore) {
            if (in_array($subscore->id, $ignoredSubscores)) {  // Ignore scores that are not for seating
                continue;
            }
            $totalScore += ($finalScoresArray[$subscore->id] * $subscore->weight);
            $totalWeight += $subscore->weight;
        }
        $totalScore = ($totalScore / $totalWeight);
        array_unshift($finalScoresArray, $totalScore);

        return $finalScoresArray;
    }

    /**
     * Validate that the judge on the score sheet is actually assigned to judge
     * then entry
     *
     * @return bool
     */
    public function validateScoreSheet(ScoreSheet $sheet)
    {
        // TODO use this when calculating scores
        $entry = $this->entryCache->getAllEntries()->find($sheet->entry_id);
        $audition = $this->auditionCache->getAudition($entry->audition_id);
        $validJudges = $audition->judges;
        // send a laravel flash message with an error if the $sheet->user_id is not in the collection $validJudges
        if (! $validJudges->contains('id', $sheet->user_id)) {
            session()->flash('error', 'Entry ID '.$sheet->entry_id.' has an invalid score entered by '.$sheet->judge->full_name());
        }

        // check if $sheet->user_id is in the collection $validJudges, return false if not, true if it is
        return $validJudges->contains('id', $sheet->user_id);

    }
}