<?php

namespace App\Http\Controllers;

use App\Models\BankReconciliation;
use App\Models\CashierLedgerEntry;
use App\Support\AuditLogger;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Storage;

class BankReconciliationController extends Controller
{
    /**
     * Display a listing of bank reconciliations
     */
    public function index(Request $request)
    {
        $query = BankReconciliation::query()
            ->with([
                'preparedByCashier',
                'reviewedByAccountant',
                'approvedByManager'
            ])
            ->orderByDesc('reconciliation_month');

        // Filter by status
        if ($request->filled('reconciliation_status')) {
            $query->where('reconciliation_status', $request->reconciliation_status);
        }

        // Filter by month
        if ($request->filled('month')) {
            $query->whereYear('reconciliation_month', '=', substr($request->month, 0, 4))
                  ->whereMonth('reconciliation_month', '=', substr($request->month, 5, 2));
        }

        $reconciliations = $query->paginate(15);

        return view('admin.bank-reconciliations.index', [
            'reconciliations' => $reconciliations,
        ]);
    }

    /**
     * Show the form for creating a new bank reconciliation
     */
    public function create(Request $request)
    {
        // Check authorization
        $this->authorize('prepare_bank_reconciliation');

        // Default to current month
        $month = $request->input('month', now()->format('Y-m'));

        // Get system book balance from cashier ledger
        $systemBalance = CashierLedgerEntry::getLatestBalance();

        return view('admin.bank-reconciliations.create', [
            'month' => $month,
            'systemBalance' => $systemBalance,
        ]);
    }

    /**
     * Store a newly created bank reconciliation
     */
    public function store(Request $request)
    {
        // Check authorization
        $this->authorize('prepare_bank_reconciliation');

        $validated = $request->validate([
            'reconciliation_month' => ['required', 'date_format:Y-m'],
            'bank_statement_balance' => ['required', 'numeric'],
            'bank_statement_date' => ['required', 'date'],
            'bank_statement_file' => ['nullable', 'file', 'max:10240'],
            'system_book_balance' => ['required', 'numeric'],
            'outstanding_checks' => ['nullable', 'array'],
            'outstanding_checks.*.amount' => ['required', 'numeric', 'min:0'],
            'outstanding_checks.*.check_number' => ['nullable', 'string'],
            'outstanding_checks.*.description' => ['nullable', 'string'],
            'deposits_in_transit' => ['nullable', 'array'],
            'deposits_in_transit.*.amount' => ['required', 'numeric', 'min:0'],
            'deposits_in_transit.*.date' => ['nullable', 'date'],
            'deposits_in_transit.*.description' => ['nullable', 'string'],
            'bank_charges' => ['nullable', 'array'],
            'bank_charges.*.amount' => ['required', 'numeric', 'min:0'],
            'bank_charges.*.description' => ['nullable', 'string'],
            'notes' => ['nullable', 'string'],
        ]);

        DB::beginTransaction();
        try {
            // Handle bank statement file upload
            $statementPath = null;
            if ($request->hasFile('bank_statement_file')) {
                $statementPath = $request->file('bank_statement_file')->store('bank-statements', 'local');
            }

            // Create reconciliation record
            $reconciliation = new BankReconciliation([
                'reconciliation_month' => $validated['reconciliation_month'] . '-01',
                'bank_statement_balance' => $validated['bank_statement_balance'],
                'bank_statement_date' => $validated['bank_statement_date'],
                'bank_statement_file_path' => $statementPath,
                'system_book_balance' => $validated['system_book_balance'],
                'outstanding_checks' => $validated['outstanding_checks'] ?? [],
                'deposits_in_transit' => $validated['deposits_in_transit'] ?? [],
                'bank_charges' => $validated['bank_charges'] ?? [],
                'prepared_by_cashier_id' => $request->user()->id,
                'prepared_at' => now(),
                'notes' => $validated['notes'] ?? null,
            ]);

            // Calculate adjusted balance
            $reconciliation->adjusted_balance = $reconciliation->calculateAdjustedBalance();

            // Calculate discrepancy
            $reconciliation->discrepancy_amount = $reconciliation->calculateDiscrepancy();

            // Set status based on discrepancy
            if ($reconciliation->hasDiscrepancy()) {
                $reconciliation->reconciliation_status = BankReconciliation::STATUS_DISCREPANCY;
            } else {
                $reconciliation->reconciliation_status = BankReconciliation::STATUS_PENDING;
            }

            $reconciliation->save();

            AuditLogger::log('bank_reconciliation.created', $reconciliation, $validated);

            DB::commit();

            $message = '銀行調節表已建立。';
            if ($reconciliation->hasDiscrepancy()) {
                $message .= ' 發現差異金額：NT$ ' . number_format($reconciliation->discrepancy_amount, 2);
            }

            return redirect()
                ->route('admin.bank-reconciliations.show', $reconciliation)
                ->with('status', $message);

        } catch (\Exception $e) {
            DB::rollBack();
            return redirect()
                ->back()
                ->withInput()
                ->with('error', '建立銀行調節表時發生錯誤：' . $e->getMessage());
        }
    }

    /**
     * Display the specified bank reconciliation
     */
    public function show(BankReconciliation $bankReconciliation)
    {
        $bankReconciliation->load([
            'preparedByCashier',
            'reviewedByAccountant',
            'approvedByManager'
        ]);

        // Get outstanding items summary
        $summary = $bankReconciliation->getOutstandingItemsSummary();

        return view('admin.bank-reconciliations.show', [
            'reconciliation' => $bankReconciliation,
            'summary' => $summary,
        ]);
    }

    /**
     * Accountant reviews the bank reconciliation
     */
    public function review(Request $request, BankReconciliation $bankReconciliation)
    {
        // Check authorization
        $this->authorize('review_bank_reconciliation');

        // Check if can be reviewed
        if (!$bankReconciliation->canBeReviewed()) {
            return redirect()
                ->route('admin.bank-reconciliations.show', $bankReconciliation)
                ->with('error', '此銀行調節表無法覆核。');
        }

        $validated = $request->validate([
            'review_notes' => ['nullable', 'string'],
        ]);

        DB::beginTransaction();
        try {
            $bankReconciliation->update([
                'reviewed_by_accountant_id' => $request->user()->id,
                'reviewed_at' => now(),
            ]);

            AuditLogger::log('bank_reconciliation.reviewed', $bankReconciliation, $validated);

            DB::commit();

            return redirect()
                ->route('admin.bank-reconciliations.show', $bankReconciliation)
                ->with('status', '銀行調節表已完成會計覆核。');

        } catch (\Exception $e) {
            DB::rollBack();
            return redirect()
                ->back()
                ->with('error', '覆核銀行調節表時發生錯誤：' . $e->getMessage());
        }
    }

    /**
     * Manager approves the bank reconciliation
     */
    public function approve(Request $request, BankReconciliation $bankReconciliation)
    {
        // Check authorization
        $this->authorize('approve_bank_reconciliation');

        // Check if can be approved
        if (!$bankReconciliation->canBeApproved()) {
            return redirect()
                ->route('admin.bank-reconciliations.show', $bankReconciliation)
                ->with('error', '此銀行調節表無法核准。');
        }

        DB::beginTransaction();
        try {
            // Determine final status
            $finalStatus = $bankReconciliation->hasDiscrepancy()
                ? BankReconciliation::STATUS_DISCREPANCY
                : BankReconciliation::STATUS_COMPLETED;

            $bankReconciliation->update([
                'approved_by_manager_id' => $request->user()->id,
                'approved_at' => now(),
                'reconciliation_status' => $finalStatus,
            ]);

            AuditLogger::log('bank_reconciliation.approved', $bankReconciliation, [
                'approved_by' => $request->user()->name,
                'final_status' => $finalStatus,
            ]);

            DB::commit();

            $message = '銀行調節表已核准。';
            if ($finalStatus === BankReconciliation::STATUS_DISCREPANCY) {
                $message .= ' 請注意：仍有差異需要處理。';
            }

            return redirect()
                ->route('admin.bank-reconciliations.show', $bankReconciliation)
                ->with('status', $message);

        } catch (\Exception $e) {
            DB::rollBack();
            return redirect()
                ->back()
                ->with('error', '核准銀行調節表時發生錯誤：' . $e->getMessage());
        }
    }

    /**
     * Download bank statement file
     */
    public function downloadStatement(BankReconciliation $bankReconciliation)
    {
        if (!$bankReconciliation->bank_statement_file_path) {
            abort(404, '找不到銀行對帳單檔案');
        }

        if (!Storage::disk('local')->exists($bankReconciliation->bank_statement_file_path)) {
            abort(404, '銀行對帳單檔案不存在');
        }

        return Storage::disk('local')->download($bankReconciliation->bank_statement_file_path);
    }

    /**
     * Export reconciliation to PDF
     */
    public function exportPdf(BankReconciliation $bankReconciliation)
    {
        // Check authorization
        $this->authorize('view_cashier_ledger');

        $bankReconciliation->load([
            'preparedByCashier',
            'reviewedByAccountant',
            'approvedByManager'
        ]);

        $summary = $bankReconciliation->getOutstandingItemsSummary();

        // Generate PDF (you would need to implement PDF generation library like DomPDF or TCPDF)
        // For now, return a view that can be printed
        return view('admin.bank-reconciliations.pdf', [
            'reconciliation' => $bankReconciliation,
            'summary' => $summary,
        ]);
    }
}