<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;

class RekomendasiController extends Controller
{
    public function index(Request $request)
    {
        if ($request->has(['nitrogen', 'fosfor', 'kalium', 'budget'])) {
            $validated = $request->validate([
                'nitrogen' => 'required|numeric|gt:0',
                'fosfor' => 'required|numeric|gt:0',
                'kalium' => 'required|numeric|gt:0',
                'budget' => 'required|numeric|gt:0'
            ], [
                'gt' => 'Nilai :attribute harus lebih dari 0',
                'required' => ':attribute tidak boleh kosong',
                'numeric' => ':attribute harus berupa angka'
            ]);

            $kebutuhan_nitrogen = (float) $request->input('nitrogen');
            $kebutuhan_fosfor = (float) $request->input('fosfor');
            $kebutuhan_kalium = (float) $request->input('kalium');
            $budget = (float) $request->input('budget');

            // Data alternatif pupuk
            $alternatifs = [
                [
                    'nama' => 'Darah ',
                    'N' => 12.18,
                    'P' => 5.28,
                    'K' => 0.15,
                    'harga' => 4000
                ],
                [
                    'nama' => 'Air Kelapa',
                    'N' => 0.39,
                    'P' => 4.95,
                    'K' => 2.85,
                    'harga' => 3000
                ],
                [
                    'nama' => 'Pisang Busuk',
                    'N' => 1.30,
                    'P' => 0.02,
                    'K' => 3.01,
                    'harga' => 2500
                ],
                [
                    'nama' => 'Urin Sapi',
                    'N' => 1.00,
                    'P' => 0.50,
                    'K' => 1.50,
                    'harga' => 1000
                ],
                [
                    'nama' => 'Air Cucian Beras',
                    'N' => 0.08,
                    'P' => 0.02,
                    'K' => 0.12,
                    'harga' => 1500
                ]
            ];

            // Bobot kriteria
            $bobot = [
                'N' => 0.40,
                'P' => 0.20,
                'K' => 0.25,
                'harga' => 0.15
            ];

            try {
                // Ambil harga minimum dari alternatif (untuk normalisasi cost)
                $min_harga = min(array_column($alternatifs, 'harga'));

                $results = [];

                foreach ($alternatifs as $a) {
                    // Normalisasi berdasarkan kebutuhan tanaman, bukan max dari alternatif
                    $normalized_N = min($a['N'] / $kebutuhan_nitrogen, 1);
                    $normalized_P = min($a['P'] / $kebutuhan_fosfor, 1);
                    $normalized_K = min($a['K'] / $kebutuhan_kalium, 1);

                    // Normalisasi harga sebagai cost: harga minimum / harga alternatif
                    $normalized_harga = $min_harga / $a['harga'];

                    // Hitung skor SAW (weighted sum)
                    $nilai = 
                        ($normalized_N * $bobot['N']) +
                        ($normalized_P * $bobot['P']) +
                        ($normalized_K * $bobot['K']) +
                        ($normalized_harga * $bobot['harga']);

                    // Filter sesuai budget
                    if ($a['harga'] <= $budget) {
                        $results[] = [
                            'nama' => $a['nama'],
                            'N' => $a['N'],
                            'P' => $a['P'],
                            'K' => $a['K'],
                            'harga' => $a['harga'],
                            'normalized_N' => round($normalized_N, 4),
                            'normalized_P' => round($normalized_P, 4),
                            'normalized_K' => round($normalized_K, 4),
                            'normalized_harga' => round($normalized_harga, 4),
                            'nilai' => round($nilai, 4)
                        ];
                    }
                }

                if (empty($results)) {
                    return back()->withErrors('Tidak ada pupuk yang sesuai dengan anggaran Anda.');
                }

                $total_nilai = array_sum(array_column($results, 'nilai'));

                foreach ($results as &$result) {
                    $result['persentase'] = round(($result['nilai'] / $total_nilai) * 100, 2);
                }

                // Urutkan dari nilai tertinggi
                usort($results, function($a, $b) {
                    return $b['nilai'] <=> $a['nilai'];
                });

                $rekomendasi = (object) $results[0];

                $input = [
                    'nitrogen' => $kebutuhan_nitrogen,
                    'fosfor' => $kebutuhan_fosfor,
                    'kalium' => $kebutuhan_kalium,
                    'budget' => $budget
                ];

                return view('user.rekomendasi.index', [
                    'alternatifs' => $results,
                    'rekomendasi' => $rekomendasi,
                    'input' => $input,
                    'maxmin' => [
                        'min_harga' => $min_harga
                    ],
                    'bobot' => $bobot
                ]);
            } catch (\Exception $e) {
                return back()->withErrors('Terjadi kesalahan dalam perhitungan: ' . $e->getMessage());
            }
        }

        return view('user.rekomendasi.index', [
            'alternatifs' => [],
            'rekomendasi' => null,
            'input' => null,
            'maxmin' => null,
            'bobot' => null
        ]);
    }
}