<?php

namespace App\Http\Controllers;

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

class BudgetController extends Controller
{
    public function index(Request $request)
    {
        $query = Budget::query()->with('createdBy', 'approvedBy');

        // Filter by fiscal year
        if ($fiscalYear = $request->integer('fiscal_year')) {
            $query->where('fiscal_year', $fiscalYear);
        }

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

        $budgets = $query->orderByDesc('fiscal_year')
            ->orderByDesc('created_at')
            ->paginate(15);

        // Get unique fiscal years for filter dropdown
        $fiscalYears = Budget::select('fiscal_year')
            ->distinct()
            ->orderByDesc('fiscal_year')
            ->pluck('fiscal_year');

        return view('admin.budgets.index', [
            'budgets' => $budgets,
            'fiscalYears' => $fiscalYears,
        ]);
    }

    public function create()
    {
        return view('admin.budgets.create');
    }

    public function store(Request $request)
    {
        $validated = $request->validate([
            'fiscal_year' => ['required', 'integer', 'min:2000', 'max:2100'],
            'name' => ['required', 'string', 'max:255'],
            'period_type' => ['required', 'in:annual,quarterly,monthly'],
            'period_start' => ['required', 'date'],
            'period_end' => ['required', 'date', 'after:period_start'],
            'notes' => ['nullable', 'string'],
        ]);

        $budget = Budget::create([
            ...$validated,
            'status' => Budget::STATUS_DRAFT,
            'created_by_user_id' => $request->user()->id,
        ]);

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

        return redirect()
            ->route('admin.budgets.edit', $budget)
            ->with('status', __('Budget created successfully. Add budget items below.'));
    }

    public function show(Budget $budget)
    {
        $budget->load([
            'createdBy',
            'approvedBy',
            'budgetItems.chartOfAccount',
            'budgetItems' => fn($q) => $q->orderBy('chart_of_account_id'),
        ]);

        // Group budget items by account type
        $incomeItems = $budget->budgetItems->filter(fn($item) => $item->chartOfAccount->isIncome());
        $expenseItems = $budget->budgetItems->filter(fn($item) => $item->chartOfAccount->isExpense());

        return view('admin.budgets.show', [
            'budget' => $budget,
            'incomeItems' => $incomeItems,
            'expenseItems' => $expenseItems,
        ]);
    }

    public function edit(Budget $budget)
    {
        if (!$budget->canBeEdited()) {
            return redirect()
                ->route('admin.budgets.show', $budget)
                ->with('error', __('This budget cannot be edited.'));
        }

        $budget->load(['budgetItems.chartOfAccount']);

        // Get all active 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();

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

    public function update(Request $request, Budget $budget)
    {
        if (!$budget->canBeEdited()) {
            abort(403, 'This budget cannot be edited.');
        }

        $validated = $request->validate([
            'name' => ['required', 'string', 'max:255'],
            'period_start' => ['required', 'date'],
            'period_end' => ['required', 'date', 'after:period_start'],
            'notes' => ['nullable', 'string'],
            'budget_items' => ['nullable', 'array'],
            'budget_items.*.chart_of_account_id' => ['required', 'exists:chart_of_accounts,id'],
            'budget_items.*.budgeted_amount' => ['required', 'numeric', 'min:0'],
            'budget_items.*.notes' => ['nullable', 'string'],
        ]);

        DB::transaction(function () use ($budget, $validated, $request) {
            // Update budget
            $budget->update([
                'name' => $validated['name'],
                'period_start' => $validated['period_start'],
                'period_end' => $validated['period_end'],
                'notes' => $validated['notes'] ?? null,
            ]);

            // Delete existing budget items and recreate
            $budget->budgetItems()->delete();

            // Create new budget items
            if (!empty($validated['budget_items'])) {
                foreach ($validated['budget_items'] as $itemData) {
                    if ($itemData['budgeted_amount'] > 0) {
                        BudgetItem::create([
                            'budget_id' => $budget->id,
                            'chart_of_account_id' => $itemData['chart_of_account_id'],
                            'budgeted_amount' => $itemData['budgeted_amount'],
                            'notes' => $itemData['notes'] ?? null,
                        ]);
                    }
                }
            }

            AuditLogger::log('budget.updated', $budget, [
                'user' => $request->user()->name,
                'items_count' => count($validated['budget_items'] ?? []),
            ]);
        });

        return redirect()
            ->route('admin.budgets.show', $budget)
            ->with('status', __('Budget updated successfully.'));
    }

    public function submit(Request $request, Budget $budget)
    {
        if (!$budget->isDraft()) {
            abort(403, 'Only draft budgets can be submitted.');
        }

        if ($budget->budgetItems()->count() === 0) {
            return redirect()
                ->route('admin.budgets.edit', $budget)
                ->with('error', __('Cannot submit budget without budget items.'));
        }

        $budget->update(['status' => Budget::STATUS_SUBMITTED]);

        AuditLogger::log('budget.submitted', $budget, ['submitted_by' => $request->user()->name]);

        return redirect()
            ->route('admin.budgets.show', $budget)
            ->with('status', __('Budget submitted for approval.'));
    }

    public function approve(Request $request, Budget $budget)
    {
        if (!$budget->canBeApproved()) {
            abort(403, 'This budget cannot be approved.');
        }

        // Check if user has permission (admin or chair)
        $user = $request->user();
        if (!$user->hasRole('chair') && !$user->is_admin && !$user->hasRole('admin')) {
            abort(403, 'Only chair can approve budgets.');
        }

        $budget->update([
            'status' => Budget::STATUS_APPROVED,
            'approved_by_user_id' => $user->id,
            'approved_at' => now(),
        ]);

        AuditLogger::log('budget.approved', $budget, ['approved_by' => $user->name]);

        return redirect()
            ->route('admin.budgets.show', $budget)
            ->with('status', __('Budget approved successfully.'));
    }

    public function activate(Request $request, Budget $budget)
    {
        if (!$budget->isApproved()) {
            abort(403, 'Only approved budgets can be activated.');
        }

        $budget->update(['status' => Budget::STATUS_ACTIVE]);

        AuditLogger::log('budget.activated', $budget, ['activated_by' => $request->user()->name]);

        return redirect()
            ->route('admin.budgets.show', $budget)
            ->with('status', __('Budget activated successfully.'));
    }

    public function close(Request $request, Budget $budget)
    {
        if (!$budget->isActive()) {
            abort(403, 'Only active budgets can be closed.');
        }

        $budget->update(['status' => Budget::STATUS_CLOSED]);

        AuditLogger::log('budget.closed', $budget, ['closed_by' => $request->user()->name]);

        return redirect()
            ->route('admin.budgets.show', $budget)
            ->with('status', __('Budget closed successfully.'));
    }

    public function destroy(Request $request, Budget $budget)
    {
        if (!$budget->isDraft()) {
            abort(403, 'Only draft budgets can be deleted.');
        }

        $fiscalYear = $budget->fiscal_year;
        $budget->delete();

        AuditLogger::log('budget.deleted', null, [
            'fiscal_year' => $fiscalYear,
            'deleted_by' => $request->user()->name,
        ]);

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