<?php

namespace App\Http\Controllers;

use App\Mail\FinanceDocumentApprovedByAccountant;
use App\Mail\FinanceDocumentApprovedByCashier;
use App\Mail\FinanceDocumentFullyApproved;
use App\Mail\FinanceDocumentRejected;
use App\Mail\FinanceDocumentSubmitted;
use App\Models\FinanceDocument;
use App\Models\Member;
use App\Models\User;
use App\Support\AuditLogger;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\Mail;

class FinanceDocumentController extends Controller
{
    public function index(Request $request)
    {
        $query = FinanceDocument::query()
            ->with(['member', 'submittedBy', 'paymentOrder']);

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

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

        // Filter by amount tier
        if ($request->filled('amount_tier')) {
            $query->where('amount_tier', $request->amount_tier);
        }

        // Filter by workflow stage
        if ($request->filled('workflow_stage')) {
            $stage = $request->workflow_stage;

            if ($stage === 'approval') {
                $query->whereNull('payment_order_created_at');
            } elseif ($stage === 'payment') {
                $query->whereNotNull('payment_order_created_at')
                      ->whereNull('payment_executed_at');
            } elseif ($stage === 'recording') {
                $query->whereNotNull('payment_executed_at')
                      ->where(function($q) {
                          $q->whereNull('cashier_ledger_entry_id')
                            ->orWhereNull('accounting_transaction_id');
                      });
            } elseif ($stage === 'completed') {
                $query->whereNotNull('cashier_ledger_entry_id')
                      ->whereNotNull('accounting_transaction_id');
            }
        }

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

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

    public function create(Request $request)
    {
        $members = Member::orderBy('full_name')->get();

        return view('admin.finance.create', [
            'members' => $members,
        ]);
    }

    public function store(Request $request)
    {
        $validated = $request->validate([
            'member_id' => ['nullable', 'exists:members,id'],
            'title' => ['required', 'string', 'max:255'],
            'amount' => ['required', 'numeric', 'min:0'],
            'request_type' => ['required', 'in:expense_reimbursement,advance_payment,purchase_request,petty_cash'],
            'description' => ['nullable', 'string'],
            'attachment' => ['nullable', 'file', 'max:10240'], // 10MB max
        ]);

        $attachmentPath = null;
        if ($request->hasFile('attachment')) {
            $attachmentPath = $request->file('attachment')->store('finance-documents', 'local');
        }

        // Create document first to use its determineAmountTier method
        $document = new FinanceDocument([
            'member_id' => $validated['member_id'] ?? null,
            'submitted_by_user_id' => $request->user()->id,
            'title' => $validated['title'],
            'amount' => $validated['amount'],
            'request_type' => $validated['request_type'],
            'description' => $validated['description'] ?? null,
            'attachment_path' => $attachmentPath,
            'status' => FinanceDocument::STATUS_PENDING,
            'submitted_at' => now(),
        ]);

        // Determine amount tier
        $document->amount_tier = $document->determineAmountTier();

        // Set if requires board meeting
        $document->requires_board_meeting = $document->needsBoardMeetingApproval();

        // Save the document
        $document->save();

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

        // Send email notification to finance cashiers
        $cashiers = User::role('finance_cashier')->get();
        if ($cashiers->isEmpty()) {
            // Fallback to old cashier role for backward compatibility
            $cashiers = User::role('cashier')->get();
        }
        foreach ($cashiers as $cashier) {
            Mail::to($cashier->email)->queue(new FinanceDocumentSubmitted($document));
        }

        return redirect()
            ->route('admin.finance.index')
            ->with('status', '財務申請單已提交。申請類型：' . $document->getRequestTypeText() . '，金額級別：' . $document->getAmountTierText());
    }

    public function show(FinanceDocument $financeDocument)
    {
        $financeDocument->load([
            'member',
            'submittedBy',
            'approvedByCashier',
            'approvedByAccountant',
            'approvedByChair',
            'rejectedBy',
            'chartOfAccount',
            'budgetItem',
            'approvedByBoardMeeting',
            'paymentOrderCreatedByAccountant',
            'paymentVerifiedByCashier',
            'paymentExecutedByCashier',
            'paymentOrder.createdByAccountant',
            'paymentOrder.verifiedByCashier',
            'paymentOrder.executedByCashier',
            'cashierLedgerEntry.recordedByCashier',
            'accountingTransaction',
        ]);

        return view('admin.finance.show', [
            'document' => $financeDocument,
        ]);
    }

    public function approve(Request $request, FinanceDocument $financeDocument)
    {
        $user = $request->user();

        // Check if user has any finance approval permissions
        $isCashier = $user->hasRole('finance_cashier') || $user->hasRole('cashier');
        $isAccountant = $user->hasRole('finance_accountant') || $user->hasRole('accountant');
        $isChair = $user->hasRole('finance_chair') || $user->hasRole('chair');

        // Determine which level of approval based on current status and user role
        if ($financeDocument->canBeApprovedByCashier() && $isCashier) {
            $financeDocument->update([
                'approved_by_cashier_id' => $user->id,
                'cashier_approved_at' => now(),
                'status' => FinanceDocument::STATUS_APPROVED_CASHIER,
            ]);

            AuditLogger::log('finance_document.approved_by_cashier', $financeDocument, [
                'approved_by' => $user->name,
                'amount_tier' => $financeDocument->amount_tier,
            ]);

            // Send email notification to accountants
            $accountants = User::role('finance_accountant')->get();
            if ($accountants->isEmpty()) {
                $accountants = User::role('accountant')->get();
            }
            foreach ($accountants as $accountant) {
                Mail::to($accountant->email)->queue(new FinanceDocumentApprovedByCashier($financeDocument));
            }

            return redirect()
                ->route('admin.finance.show', $financeDocument)
                ->with('status', '出納已審核通過。已送交會計審核。');
        }

        if ($financeDocument->canBeApprovedByAccountant() && $isAccountant) {
            $financeDocument->update([
                'approved_by_accountant_id' => $user->id,
                'accountant_approved_at' => now(),
                'status' => FinanceDocument::STATUS_APPROVED_ACCOUNTANT,
            ]);

            AuditLogger::log('finance_document.approved_by_accountant', $financeDocument, [
                'approved_by' => $user->name,
                'amount_tier' => $financeDocument->amount_tier,
            ]);

            // For small amounts, approval is complete (no chair needed)
            if ($financeDocument->amount_tier === FinanceDocument::AMOUNT_TIER_SMALL) {
                return redirect()
                    ->route('admin.finance.show', $financeDocument)
                    ->with('status', '會計已審核通過。小額申請審核完成，可以製作付款單。');
            }

            // For medium and large amounts, send to chair
            $chairs = User::role('finance_chair')->get();
            if ($chairs->isEmpty()) {
                $chairs = User::role('chair')->get();
            }
            foreach ($chairs as $chair) {
                Mail::to($chair->email)->queue(new FinanceDocumentApprovedByAccountant($financeDocument));
            }

            return redirect()
                ->route('admin.finance.show', $financeDocument)
                ->with('status', '會計已審核通過。已送交理事長審核。');
        }

        if ($financeDocument->canBeApprovedByChair() && $isChair) {
            $financeDocument->update([
                'approved_by_chair_id' => $user->id,
                'chair_approved_at' => now(),
                'status' => FinanceDocument::STATUS_APPROVED_CHAIR,
            ]);

            AuditLogger::log('finance_document.approved_by_chair', $financeDocument, [
                'approved_by' => $user->name,
                'amount_tier' => $financeDocument->amount_tier,
                'requires_board_meeting' => $financeDocument->requires_board_meeting,
            ]);

            // For large amounts, notify that board meeting approval is still needed
            if ($financeDocument->requires_board_meeting && !$financeDocument->board_meeting_approved_at) {
                return redirect()
                    ->route('admin.finance.show', $financeDocument)
                    ->with('status', '理事長已審核通過。大額申請仍需理事會核准。');
            }

            // For medium amounts or large amounts with board approval, complete
            Mail::to($financeDocument->submittedBy->email)->queue(new FinanceDocumentFullyApproved($financeDocument));

            return redirect()
                ->route('admin.finance.show', $financeDocument)
                ->with('status', '審核流程完成。會計可以製作付款單。');
        }

        abort(403, 'You are not authorized to approve this document at this stage.');
    }

    public function reject(Request $request, FinanceDocument $financeDocument)
    {
        $validated = $request->validate([
            'rejection_reason' => ['required', 'string', 'max:1000'],
        ]);

        $user = $request->user();

        // Can be rejected by cashier, accountant, or chair at any stage (except if already rejected or fully approved)
        if ($financeDocument->isRejected() || $financeDocument->isFullyApproved()) {
            abort(403, '此文件無法駁回。');
        }

        // Check if user has permission to reject
        $canReject = $user->hasRole('finance_cashier') || $user->hasRole('cashier') ||
                     $user->hasRole('finance_accountant') || $user->hasRole('accountant') ||
                     $user->hasRole('finance_chair') || $user->hasRole('chair');

        if (!$canReject) {
            abort(403, '您無權駁回此文件。');
        }

        $financeDocument->update([
            'rejected_by_user_id' => $user->id,
            'rejected_at' => now(),
            'rejection_reason' => $validated['rejection_reason'],
            'status' => FinanceDocument::STATUS_REJECTED,
        ]);

        AuditLogger::log('finance_document.rejected', $financeDocument, [
            'rejected_by' => $user->name,
            'reason' => $validated['rejection_reason'],
            'amount_tier' => $financeDocument->amount_tier,
        ]);

        // Send email notification to submitter (rejected)
        Mail::to($financeDocument->submittedBy->email)->queue(new FinanceDocumentRejected($financeDocument));

        return redirect()
            ->route('admin.finance.show', $financeDocument)
            ->with('status', '財務申請單已駁回。');
    }

    public function download(FinanceDocument $financeDocument)
    {
        if (!$financeDocument->attachment_path) {
            abort(404, 'No attachment found.');
        }

        $path = storage_path('app/' . $financeDocument->attachment_path);

        if (!file_exists($path)) {
            abort(404, 'Attachment file not found.');
        }

        return response()->download($path);
    }
}