<?php

namespace App\Http\Controllers\Admin;

use App\Http\Controllers\Controller;
use App\Models\Book;
use App\Models\Loan;
use App\Models\User;
use Carbon\Carbon;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\DB;

class AdminPeminjamanController extends Controller
{
    public function index(Request $request)
    {
        $loans = Loan::with(['user', 'book'])
            ->whereIn('status', ['Dipinjam', 'Terlambat'])
            ->get();

        $groupedLoans = $loans->groupBy('user_id');

        $peminjamanAktif = $groupedLoans->map(function ($userLoans, $userId) {
            $user = $userLoans->first()->user;
            $firstLoan = $userLoans->first();

            return [
                'id_peminjaman' => 'PIN-ADM-'.sprintf('%03d', $userId),
                'user_id' => $userId,
                'peminjam' => $user->nama_lengkap ?? 'Unknown',
                'email' => $user->email,
                'nomor_hp' => $user->phone ?? '-',
                'tanggal_pinjam' => $firstLoan->borrowed_at,
                'tenggat_kembali' => $firstLoan->due_at,
                'status' => $firstLoan->status,
                'role' => $user->role,
                'books' => $userLoans->map(fn ($l) => [
                    'id' => $l->book->id,
                    'judul' => $l->book->judul,
                    'cover' => $l->book->cover,
                ])->toArray(),
            ];
        })->values();

        $daftarPeminjam = $peminjamanAktif->pluck('peminjam')->unique();

        return view('admin.peminjaman.index', [
            'pageTitle' => 'Manajemen Peminjaman',
            'peminjamanAktif' => $peminjamanAktif,
            'daftarPeminjam' => $daftarPeminjam,
        ]);
    }

    public function create()
    {
        $users = User::whereIn('role', ['siswa', 'guru'])->get();

        $groupedUsers = $users->map(function ($user) {
            $jumlahPinjam = Loan::where('user_id', $user->id)
                ->whereIn('status', ['Dipinjam', 'Terlambat'])
                ->count();

            $user->jumlah_pinjam = $jumlahPinjam;
            $user->kena_limit = $jumlahPinjam >= 2;
            $user->disabled = $user->kena_limit || $user->is_banned;

            if ($user->is_banned) {
                $user->status_text = '(Akun Dibekukan)';
            } elseif ($user->kena_limit) {
                $user->status_text = '(Limit Penuh: 2/2)';
            } else {
                $user->status_text = '';
            }

            return $user;
        })->groupBy('role');

        $daftarBuku = Book::where('status', 'Tersedia')
            ->whereJsonContains('tipe_akses', 'offline')
            ->where('stok', '>', 0)
            ->get();

        return view('admin.peminjaman.create', [
            'pageTitle' => 'Buat Peminjaman Manual',
            'groupedUsers' => $groupedUsers,
            'daftarBuku' => $daftarBuku,
        ]);
    }

    public function store(Request $request)
    {
        $validated = $request->validate([
            'peminjam_id' => 'required|exists:users,id',
            'tanggal_pinjam' => 'required|date',
            'tanggal_kembali' => 'required|date|after:tanggal_pinjam',
            'buku_ids' => 'required|array|min:1|max:2',
            'buku_ids.*' => 'exists:books,id',
        ]);

        \DB::beginTransaction();
        try {
            foreach ($validated['buku_ids'] as $bookId) {
                $book = Book::findOrFail($bookId);

                // Check if book is available
                if ($book->status !== 'Tersedia') {
                    throw new \Exception("Buku '{$book->judul}' tidak tersedia.");
                }

                // Check stock
                if ($book->stok <= 0) {
                    throw new \Exception("Buku '{$book->judul}' stok habis.");
                }

                // Create loan record
                Loan::create([
                    'user_id' => $validated['peminjam_id'],
                    'book_id' => $bookId,
                    'loan_code' => 'LOAN-'.date('Ymd').'-'.strtoupper(substr(md5(uniqid()), 0, 6)),
                    'borrowed_at' => $validated['tanggal_pinjam'],
                    'due_at' => $validated['tanggal_kembali'],
                    'status' => 'Dipinjam',
                ]);

                // Update book status and decrement stock
                $book->update([
                    'status' => 'Dipinjam',
                    'stok' => $book->stok - 1,
                ]);
            }

            \DB::commit();

            return redirect()->route('admin.peminjaman.index')->with('success', 'Peminjaman berhasil dibuat.');
        } catch (\Exception $e) {
            \DB::rollBack();

            return back()->withErrors(['error' => $e->getMessage()])->withInput();
        }
    }

    public function export(Request $request)
    {
        $request->validate([
            'bulan_laporan' => 'nullable|date',
        ]);

        $query = Loan::with(['user', 'book'])->orderBy('borrowed_at', 'asc');

        if ($request->filled('bulan_laporan')) {
            $date = Carbon::parse($request->bulan_laporan);
            $query->whereMonth('borrowed_at', $date->month)
                  ->whereYear('borrowed_at', $date->year);
            $fileName = 'Laporan_Peminjaman_'.$date->format('Y-m').'.xls'; // Changed to .xls
        } else {
            $fileName = 'Laporan_Peminjaman_Semua.xls'; // Changed to .xls
        }

        $loans = $query->get();

        $headers = [
            "Content-Type"        => "application/vnd.ms-excel",
            "Content-Disposition" => "attachment; filename=$fileName",
            "Pragma"              => "no-cache",
            "Cache-Control"       => "must-revalidate, post-check=0, pre-check=0",
            "Expires"             => "0"
        ];

        $columns = ['NO', 'ID PEMINJAMAN', 'PEMINJAM', 'ROLE', 'JUDUL BUKU', 'TGL PINJAM', 'TENGGAT KEMBALI', 'STATUS', 'DENDA KETERLAMBATAN'];

        $callback = function() use($loans, $columns) {
            $file = fopen('php://output', 'w');
            
            // Generate HTML table for Excel
            echo '<table border="1">';
            echo '<thead><tr style="background-color: #f2f2f2;">';
            foreach($columns as $col) echo "<th>$col</th>";
            echo '</tr></thead>';
            echo '<tbody>';

            $i = 1;
            foreach ($loans as $loan) {
                echo '<tr>';
                echo "<td>" . $i++ . "</td>";
                echo "<td>" . ($loan->loan_code ?? '-') . "</td>";
                echo "<td>" . ($loan->user->nama_lengkap ?? 'Unknown') . "</td>";
                echo "<td>" . ($loan->user->role ?? '-') . "</td>";
                echo "<td>" . ($loan->book->judul ?? 'Unknown') . "</td>";
                echo "<td>" . $loan->borrowed_at->format('d/m/Y') . "</td>";
                echo "<td>" . ($loan->due_at ? $loan->due_at->format('d/m/Y') : '-') . "</td>";
                echo "<td>" . ($loan->status ?? '-') . "</td>";
                echo "<td>" . ($loan->fine_overdue ?? 0) . "</td>";
                echo '</tr>';
            }
            echo '</tbody></table>';

            fclose($file);
        };

        return response()->stream($callback, 200, $headers);
    }

    public function dendaIndex()
    {
        $now = Carbon::now();

        // Fetch all loans that are overdue or users that are banned
        $loans = Loan::with(['user', 'book'])
            ->where(function ($query) use ($now) {
                $query->where('due_at', '<', $now)
                    ->whereIn('status', ['Dipinjam', 'Terlambat']);
            })
            ->orWhereHas('user', function ($query) {
                $query->where('is_banned', true);
            })
            ->get();

        $groupedLoans = $loans->groupBy('user_id');

        $siswaTelat = $groupedLoans->map(function ($userLoans, $userId) use ($now) {
            $user = $userLoans->first()->user;
            $firstLoan = $userLoans->first();

            $tenggat = Carbon::parse($firstLoan->due_at);
            $hariTelat = $now->greaterThan($tenggat) ? (int) $tenggat->diffInDays($now) : 0;

            $isGuru = $user->role === 'guru';
            $totalDenda = $isGuru ? 0 : ($hariTelat * 1000);

            // Link WA
            $hp = $user->phone ?? '';
            $waLink = '#';
            if ($hp) {
                if (substr($hp, 0, 1) == '0') {
                    $hp = '62'.substr($hp, 1);
                }

                if ($isGuru && $hariTelat > 0) {
                    $pesan = "Halo Bapak/Ibu {$user->nama_lengkap}, anda terlambat pengembalian buku selama {$hariTelat} hari. Mohon segera dikembalikan ke perpustakaan. Terima kasih.";
                } else {
                    $pesan = $hariTelat > 0
                        ? "Halo {$user->nama_lengkap}, anda terlambat pengembalian buku. Total Denda: Rp ".number_format($totalDenda, 0, ',', '.')
                        : "Halo {$user->nama_lengkap}, akun anda sedang dinonaktifkan sementara. Mohon hubungi petugas.";
                }

                $waLink = "https://wa.me/{$hp}?text=".urlencode($pesan);
            }

            return [
                'id' => $firstLoan->id,
                'user_id' => $userId,
                'peminjam' => $user->nama_lengkap,
                'nomor_hp' => $user->phone ?? '-',
                'kelas' => $user->kelas ?? 'Guru',
                'hari_terlambat' => $hariTelat,
                'total_denda' => $totalDenda,
                'is_guru' => $isGuru,
                'wa_link' => $waLink,
                'is_banned' => $user->is_banned,
                'tenggat_kembali' => $firstLoan->due_at,
                'books' => $userLoans->map(fn ($l) => [
                    'id' => $l->book->id,
                    'judul' => $l->book->judul,
                ])->toArray(),
            ];
        })->values();

        $listKelas = $siswaTelat->pluck('kelas')->unique()->values();

        return view('admin.denda.index', [
            'pageTitle' => 'Manajemen Denda & Sanksi',
            'siswaTelat' => $siswaTelat,
            'listKelas' => $listKelas,
        ]);
    }

    public function berikanSanksi(Request $request)
    {
        $validated = $request->validate([
            'user_id' => 'required|exists:users,id',
            'action' => 'required|in:ban,unban',
        ]);

        $user = User::findOrFail($validated['user_id']);
        $user->is_banned = ($validated['action'] === 'ban');
        $user->save();

        return response()->json([
            'status' => 'success',
            'message' => $user->is_banned ? "Akun {$user->nama_lengkap} berhasil dibekukan." : "Akun {$user->nama_lengkap} telah diaktifkan kembali.",
        ]);
    }

    public function kembalikan(Request $request)
    {
        $validated = $request->validate([
            'user_id' => 'required|exists:users,id',
            'returns' => 'required|array',
            'returns.*.book_id' => 'required|exists:books,id',
            'returns.*.condition' => 'required|string',
            'returns.*.fine_damage' => 'required|integer',
            'returns.*.fine_overdue' => 'required|integer',
            'returns.*.notes' => 'nullable|string',
        ]);

        \DB::beginTransaction();
        try {
            foreach ($validated['returns'] as $item) {
                $loan = Loan::where('user_id', $validated['user_id'])
                    ->where('book_id', $item['book_id'])
                    ->whereIn('status', ['Dipinjam', 'Terlambat'])
                    ->first();

                if ($loan) {
                    $loan->update([
                        'status' => 'Dikembalikan',
                        'returned_at' => now(),
                        'condition' => $item['condition'],
                        'fine_damage' => $item['fine_damage'],
                        'fine_overdue' => $item['fine_overdue'],
                        'return_notes' => $item['notes'],
                    ]);

                    // Update book status and increment stock
                    $loan->book->update([
                        'status' => 'Tersedia',
                        'stok' => $loan->book->stok + 1,
                    ]);
                }
            }

            \DB::commit();

            return response()->json(['status' => 'success', 'message' => 'Buku berhasil dikembalikan.']);
        } catch (\Exception $e) {
            \DB::rollBack();

            return response()->json(['status' => 'error', 'message' => $e->getMessage()], 500);
        }
    }
}