<?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 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'],
            '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'],
            '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
        $cashiers = User::role('finance_cashier')->get();
        foreach ($cashiers as $cashier) {
            Mail::to($cashier->email)->queue(new FinanceDocumentSubmitted($document));
        }

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

    public function show(FinanceDocument $financeDocument)
    {
        $financeDocument->load([
            'member',
            'submittedBy',
            // 新工作流程 relationships
            'approvedBySecretary',
            'approvedByChair',
            'approvedByBoardMeeting',
            'requesterConfirmedBy',
            'cashierConfirmedBy',
            'accountantRecordedBy',
            // Legacy relationships
            'approvedByCashier',
            'approvedByAccountant',
            'rejectedBy',
            'chartOfAccount',
            'budgetItem',
            '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();

        // 新工作流程：秘書長 → 理事長 → 董理事會
        $isSecretary = $user->hasRole('secretary_general');
        $isChair = $user->hasRole('finance_chair');
        $isBoardMember = $user->hasRole('finance_board_member');
        $isAdmin = $user->hasRole('admin');

        // 秘書長審核（第一階段）
        if ($financeDocument->canBeApprovedBySecretary($user) && ($isSecretary || $isAdmin)) {
            $financeDocument->update([
                'approved_by_secretary_id' => $user->id,
                'secretary_approved_at' => now(),
                'status' => FinanceDocument::STATUS_APPROVED_SECRETARY,
            ]);

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

            // 小額：審核完成
            if ($financeDocument->amount_tier === FinanceDocument::AMOUNT_TIER_SMALL) {
                // 通知申請人審核已完成，可以領款
                Mail::to($financeDocument->submittedBy->email)->queue(new FinanceDocumentFullyApproved($financeDocument));

                return redirect()
                    ->route('admin.finance.show', $financeDocument)
                    ->with('status', '秘書長已核准。小額申請審核完成，申請人可向出納領款。');
            }

            // 中額/大額：送交理事長
            $chairs = User::role('finance_chair')->get();
            foreach ($chairs as $chair) {
                Mail::to($chair->email)->queue(new FinanceDocumentApprovedByAccountant($financeDocument));
            }

            return redirect()
                ->route('admin.finance.show', $financeDocument)
                ->with('status', '秘書長已核准。已送交理事長審核。');
        }

        // 理事長審核（第二階段：中額或大額）
        if ($financeDocument->canBeApprovedByChair($user) && ($isChair || $isAdmin)) {
            $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,
            ]);

            // 中額：審核完成
            if ($financeDocument->amount_tier === FinanceDocument::AMOUNT_TIER_MEDIUM) {
                Mail::to($financeDocument->submittedBy->email)->queue(new FinanceDocumentFullyApproved($financeDocument));

                return redirect()
                    ->route('admin.finance.show', $financeDocument)
                    ->with('status', '理事長已核准。中額申請審核完成，申請人可向出納領款。');
            }

            // 大額：送交董理事會
            $boardMembers = User::role('finance_board_member')->get();
            foreach ($boardMembers as $member) {
                Mail::to($member->email)->queue(new FinanceDocumentApprovedByAccountant($financeDocument));
            }

            return redirect()
                ->route('admin.finance.show', $financeDocument)
                ->with('status', '理事長已核准。大額申請需送交董理事會審核。');
        }

        // 董理事會審核（第三階段：大額）
        if ($financeDocument->canBeApprovedByBoard($user) && ($isBoardMember || $isAdmin)) {
            $financeDocument->update([
                'board_meeting_approved_by_id' => $user->id,
                'board_meeting_approved_at' => now(),
                'status' => FinanceDocument::STATUS_APPROVED_BOARD,
            ]);

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

            Mail::to($financeDocument->submittedBy->email)->queue(new FinanceDocumentFullyApproved($financeDocument));

            return redirect()
                ->route('admin.finance.show', $financeDocument)
                ->with('status', '董理事會已核准。審核流程完成，申請人可向出納領款。');
        }

        abort(403, '您無權在此階段審核此文件。');
    }

    /**
     * 出帳確認（雙重確認：申請人 + 出納）
     */
    public function confirmDisbursement(Request $request, FinanceDocument $financeDocument)
    {
        $user = $request->user();

        $isRequester = $financeDocument->submitted_by_user_id === $user->id;
        $isCashier = $user->hasRole('finance_cashier');
        $isAdmin = $user->hasRole('admin');

        // 申請人確認
        if ($isRequester && $financeDocument->canRequesterConfirmDisbursement($user)) {
            $financeDocument->update([
                'requester_confirmed_at' => now(),
                'requester_confirmed_by_id' => $user->id,
            ]);

            AuditLogger::log('finance_document.requester_confirmed_disbursement', $financeDocument, [
                'confirmed_by' => $user->name,
            ]);

            // 檢查是否雙重確認完成
            if ($financeDocument->isDisbursementComplete()) {
                $financeDocument->update(['disbursement_status' => FinanceDocument::DISBURSEMENT_COMPLETED]);
                return redirect()
                    ->route('admin.finance.show', $financeDocument)
                    ->with('status', '出帳確認完成。等待會計入帳。');
            }

            return redirect()
                ->route('admin.finance.show', $financeDocument)
                ->with('status', '申請人已確認領款。等待出納確認。');
        }

        // 出納確認
        if (($isCashier || $isAdmin) && $financeDocument->canCashierConfirmDisbursement()) {
            $financeDocument->update([
                'cashier_confirmed_at' => now(),
                'cashier_confirmed_by_id' => $user->id,
            ]);

            AuditLogger::log('finance_document.cashier_confirmed_disbursement', $financeDocument, [
                'confirmed_by' => $user->name,
            ]);

            // 檢查是否雙重確認完成
            if ($financeDocument->isDisbursementComplete()) {
                $financeDocument->update(['disbursement_status' => FinanceDocument::DISBURSEMENT_COMPLETED]);
                return redirect()
                    ->route('admin.finance.show', $financeDocument)
                    ->with('status', '出帳確認完成。等待會計入帳。');
            }

            return redirect()
                ->route('admin.finance.show', $financeDocument)
                ->with('status', '出納已確認出帳。等待申請人確認。');
        }

        abort(403, '您無權確認此出帳。');
    }

    /**
     * 入帳確認（會計）
     */
    public function confirmRecording(Request $request, FinanceDocument $financeDocument)
    {
        $user = $request->user();

        $isAccountant = $user->hasRole('finance_accountant');
        $isAdmin = $user->hasRole('admin');

        if (!$financeDocument->canAccountantConfirmRecording()) {
            abort(403, '此文件尚未完成出帳確認，無法入帳。');
        }

        if (!$isAccountant && !$isAdmin) {
            abort(403, '只有會計可以確認入帳。');
        }

        $financeDocument->update([
            'accountant_recorded_at' => now(),
            'accountant_recorded_by_id' => $user->id,
            'recording_status' => FinanceDocument::RECORDING_COMPLETED,
        ]);

        // 自動產生會計分錄
        $financeDocument->autoGenerateAccountingEntries();

        AuditLogger::log('finance_document.accountant_confirmed_recording', $financeDocument, [
            'confirmed_by' => $user->name,
        ]);

        return redirect()
            ->route('admin.finance.show', $financeDocument)
            ->with('status', '會計已確認入帳。財務流程完成。');
    }

    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('admin') ||
                     $user->hasRole('secretary_general') ||
                     $user->hasRole('finance_cashier') ||
                     $user->hasRole('finance_accountant') ||
                     $user->hasRole('finance_chair') ||
                     $user->hasRole('finance_board_member');

        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', '報銷申請單已駁回。');
    }

    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);
    }
}