<?php

namespace App\Http\Controllers;

use App\Models\User;

class CompareController extends Controller
{
    public function show(User $user)
    {
        if (auth()->id() === $user->id) {
            return redirect()->route('users.show', $user->username);
        }

        $myGames    = auth()->user()->library()->with('game')->get()->keyBy('game_id');
        $theirGames = $user->library()->with('game')->get()->keyBy('game_id');

        $myIds    = $myGames->keys()->values();
        $theirIds = $theirGames->keys()->values();

        $bothIds          = $myIds->intersect($theirIds)->values();
        $theyHaveNotYouIds = $theirIds->diff($myIds)->values();
        $youHaveNotThemIds = $myIds->diff($theirIds)->values();

        $both = $bothIds->map(fn($id) => [
            'game'       => $myGames[$id]->game,
            'myEntry'    => $myGames[$id],
            'theirEntry' => $theirGames[$id],
        ])->filter(fn($item) => $item['game'] !== null)->values();

        $theyHaveNotYou = $theyHaveNotYouIds
            ->map(fn($id) => $theirGames[$id])
            ->filter(fn($ug) => $ug->game !== null)
            ->values();

        $youHaveNotThem = $youHaveNotThemIds
            ->map(fn($id) => $myGames[$id])
            ->filter(fn($ug) => $ug->game !== null)
            ->values();

        // Average rating diff on games both rated
        $diffSum   = 0;
        $diffCount = 0;
        foreach ($bothIds as $id) {
            $myRating    = $myGames[$id]->rating;
            $theirRating = $theirGames[$id]->rating;
            if ($myRating !== null && $theirRating !== null) {
                $diffSum += abs($myRating - $theirRating);
                $diffCount++;
            }
        }

        $stats = [
            'both_count'     => $bothIds->count(),
            'they_not_you'   => $theyHaveNotYouIds->count(),
            'you_not_them'   => $youHaveNotThemIds->count(),
            'avg_rating_diff' => $diffCount > 0 ? round($diffSum / $diffCount, 1) : null,
        ];

        return view('compare.show', compact('user', 'both', 'theyHaveNotYou', 'youHaveNotThem', 'stats'));
    }
}