<?php

namespace App\Http\Controllers;

use App\Models\Budget;
use App\Models\BudgetItem;
use App\Models\ChartOfAccount;
use App\Models\Transaction;
use App\Support\AuditLogger;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\DB;

class TransactionController extends Controller
{
    public function index(Request $request)
    {
        $query = Transaction::query()
            ->with(['chartOfAccount', 'budgetItem.budget', 'createdBy']);

        // Filter by transaction type
        if ($type = $request->string('transaction_type')->toString()) {
            $query->where('transaction_type', $type);
        }

        // Filter by account
        if ($accountId = $request->integer('chart_of_account_id')) {
            $query->where('chart_of_account_id', $accountId);
        }

        // Filter by budget
        if ($budgetId = $request->integer('budget_id')) {
            $query->whereHas('budgetItem', fn($q) => $q->where('budget_id', $budgetId));
        }

        // Filter by date range
        if ($startDate = $request->date('start_date')) {
            $query->where('transaction_date', '>=', $startDate);
        }
        if ($endDate = $request->date('end_date')) {
            $query->where('transaction_date', '<=', $endDate);
        }

        // Search description
        if ($search = $request->string('search')->toString()) {
            $query->where(function ($q) use ($search) {
                $q->where('description', 'like', "%{$search}%")
                    ->orWhere('reference_number', 'like', "%{$search}%");
            });
        }

        $transactions = $query->orderByDesc('transaction_date')
            ->orderByDesc('created_at')
            ->paginate(20);

        // Get filter options
        $accounts = ChartOfAccount::where('is_active', true)
            ->whereIn('account_type', ['income', 'expense'])
            ->orderBy('account_code')
            ->get();

        $budgets = Budget::orderByDesc('fiscal_year')->get();

        // Calculate totals
        $totalIncome = (clone $query)->income()->sum('amount');
        $totalExpense = (clone $query)->expense()->sum('amount');

        return view('admin.transactions.index', [
            'transactions' => $transactions,
            'accounts' => $accounts,
            'budgets' => $budgets,
            'totalIncome' => $totalIncome,
            'totalExpense' => $totalExpense,
        ]);
    }

    public function create(Request $request)
    {
        // Get active budgets
        $budgets = Budget::whereIn('status', [Budget::STATUS_ACTIVE, Budget::STATUS_APPROVED])
            ->orderByDesc('fiscal_year')
            ->get();

        // Get income and expense accounts
        $incomeAccounts = ChartOfAccount::where('account_type', 'income')
            ->where('is_active', true)
            ->orderBy('account_code')
            ->get();

        $expenseAccounts = ChartOfAccount::where('account_type', 'expense')
            ->where('is_active', true)
            ->orderBy('account_code')
            ->get();

        // Pre-select budget if provided
        $selectedBudgetId = $request->integer('budget_id');

        return view('admin.transactions.create', [
            'budgets' => $budgets,
            'incomeAccounts' => $incomeAccounts,
            'expenseAccounts' => $expenseAccounts,
            'selectedBudgetId' => $selectedBudgetId,
        ]);
    }

    public function store(Request $request)
    {
        $validated = $request->validate([
            'chart_of_account_id' => ['required', 'exists:chart_of_accounts,id'],
            'transaction_date' => ['required', 'date'],
            'amount' => ['required', 'numeric', 'min:0.01'],
            'transaction_type' => ['required', 'in:income,expense'],
            'description' => ['required', 'string', 'max:255'],
            'reference_number' => ['nullable', 'string', 'max:255'],
            'budget_item_id' => ['nullable', 'exists:budget_items,id'],
            'notes' => ['nullable', 'string'],
        ]);

        DB::transaction(function () use ($validated, $request) {
            $transaction = Transaction::create([
                ...$validated,
                'created_by_user_id' => $request->user()->id,
            ]);

            // Update budget item actual amount if linked
            if ($transaction->budget_item_id) {
                $this->updateBudgetItemActual($transaction->budget_item_id);
            }

            AuditLogger::log('transaction.created', $transaction, [
                'user' => $request->user()->name,
                'amount' => $validated['amount'],
                'type' => $validated['transaction_type'],
            ]);
        });

        return redirect()
            ->route('admin.transactions.index')
            ->with('status', __('Transaction recorded successfully.'));
    }

    public function show(Transaction $transaction)
    {
        $transaction->load([
            'chartOfAccount',
            'budgetItem.budget',
            'budgetItem.chartOfAccount',
            'financeDocument',
            'membershipPayment',
            'createdBy',
        ]);

        return view('admin.transactions.show', [
            'transaction' => $transaction,
        ]);
    }

    public function edit(Transaction $transaction)
    {
        // Only allow editing if not linked to finance document or payment
        if ($transaction->finance_document_id || $transaction->membership_payment_id) {
            return redirect()
                ->route('admin.transactions.show', $transaction)
                ->with('error', __('Cannot edit auto-generated transactions.'));
        }

        $budgets = Budget::whereIn('status', [Budget::STATUS_ACTIVE, Budget::STATUS_APPROVED])
            ->orderByDesc('fiscal_year')
            ->get();

        $incomeAccounts = ChartOfAccount::where('account_type', 'income')
            ->where('is_active', true)
            ->orderBy('account_code')
            ->get();

        $expenseAccounts = ChartOfAccount::where('account_type', 'expense')
            ->where('is_active', true)
            ->orderBy('account_code')
            ->get();

        return view('admin.transactions.edit', [
            'transaction' => $transaction,
            'budgets' => $budgets,
            'incomeAccounts' => $incomeAccounts,
            'expenseAccounts' => $expenseAccounts,
        ]);
    }

    public function update(Request $request, Transaction $transaction)
    {
        // Only allow editing if not auto-generated
        if ($transaction->finance_document_id || $transaction->membership_payment_id) {
            abort(403, 'Cannot edit auto-generated transactions.');
        }

        $validated = $request->validate([
            'chart_of_account_id' => ['required', 'exists:chart_of_accounts,id'],
            'transaction_date' => ['required', 'date'],
            'amount' => ['required', 'numeric', 'min:0.01'],
            'description' => ['required', 'string', 'max:255'],
            'reference_number' => ['nullable', 'string', 'max:255'],
            'budget_item_id' => ['nullable', 'exists:budget_items,id'],
            'notes' => ['nullable', 'string'],
        ]);

        DB::transaction(function () use ($transaction, $validated, $request) {
            $oldBudgetItemId = $transaction->budget_item_id;

            $transaction->update($validated);

            // Update budget item actuals
            if ($oldBudgetItemId) {
                $this->updateBudgetItemActual($oldBudgetItemId);
            }
            if ($transaction->budget_item_id && $transaction->budget_item_id != $oldBudgetItemId) {
                $this->updateBudgetItemActual($transaction->budget_item_id);
            }

            AuditLogger::log('transaction.updated', $transaction, [
                'user' => $request->user()->name,
            ]);
        });

        return redirect()
            ->route('admin.transactions.show', $transaction)
            ->with('status', __('Transaction updated successfully.'));
    }

    public function destroy(Request $request, Transaction $transaction)
    {
        // Only allow deleting if not auto-generated
        if ($transaction->finance_document_id || $transaction->membership_payment_id) {
            abort(403, 'Cannot delete auto-generated transactions.');
        }

        $budgetItemId = $transaction->budget_item_id;

        DB::transaction(function () use ($transaction, $budgetItemId, $request) {
            $transaction->delete();

            // Update budget item actual
            if ($budgetItemId) {
                $this->updateBudgetItemActual($budgetItemId);
            }

            AuditLogger::log('transaction.deleted', null, [
                'user' => $request->user()->name,
                'description' => $transaction->description,
                'amount' => $transaction->amount,
            ]);
        });

        return redirect()
            ->route('admin.transactions.index')
            ->with('status', __('Transaction deleted successfully.'));
    }

    /**
     * Update budget item actual amount based on all transactions
     */
    protected function updateBudgetItemActual(int $budgetItemId): void
    {
        $budgetItem = BudgetItem::find($budgetItemId);
        if (!$budgetItem) {
            return;
        }

        $actualAmount = Transaction::where('budget_item_id', $budgetItemId)
            ->sum('amount');

        $budgetItem->update(['actual_amount' => $actualAmount]);
    }
}