<?php

namespace App\Http\Controllers\ESign;

use App\Http\Controllers\Controller;
use App\Mail\EsignRequestMail;
use App\Models\ESign\EsignContract;
use App\Models\ESign\EsignFieldTemplate;
use App\Models\ESign\EsignFieldTemplateItem;
use App\Models\ESign\EsignSigner;
use App\Models\ESign\EsignSignField;
use App\Models\ESign\EsignAuditLog;
use Illuminate\Http\JsonResponse;
use Illuminate\Http\Request;
use Illuminate\Support\Facades\DB;
use Illuminate\Support\Facades\Mail;
use Illuminate\Support\Str;

class EsignApiController extends Controller
{
    /**
     * 상태별 통계
     */
    public function stats(): JsonResponse
    {
        $tenantId = session('selected_tenant_id', 1);
        $contracts = EsignContract::forTenant($tenantId)->get();

        $stats = [
            'total' => $contracts->count(),
            'draft' => $contracts->where('status', 'draft')->count(),
            'pending' => $contracts->where('status', 'pending')->count(),
            'partially_signed' => $contracts->where('status', 'partially_signed')->count(),
            'completed' => $contracts->where('status', 'completed')->count(),
            'expired' => $contracts->where('status', 'expired')->count(),
            'cancelled' => $contracts->where('status', 'cancelled')->count(),
            'rejected' => $contracts->where('status', 'rejected')->count(),
        ];

        return response()->json(['success' => true, 'data' => $stats]);
    }

    /**
     * 계약 목록 (페이지네이션)
     */
    public function index(Request $request): JsonResponse
    {
        $tenantId = session('selected_tenant_id', 1);
        $query = EsignContract::forTenant($tenantId)->with(['signers:id,contract_id,name,role,status']);

        if ($status = $request->input('status')) {
            $query->where('status', $status);
        }
        if ($search = $request->input('search')) {
            $query->where(function ($q) use ($search) {
                $q->where('title', 'like', "%{$search}%")
                  ->orWhere('contract_code', 'like', "%{$search}%");
            });
        }

        $perPage = $request->input('per_page', 20);
        $data = $query->orderBy('created_at', 'desc')->paginate($perPage);

        return response()->json(['success' => true, 'data' => $data]);
    }

    /**
     * 계약 상세 조회
     */
    public function show(int $id): JsonResponse
    {
        $tenantId = session('selected_tenant_id', 1);
        $contract = EsignContract::forTenant($tenantId)
            ->with(['signers', 'signFields', 'auditLogs' => fn($q) => $q->orderBy('created_at', 'desc')])
            ->findOrFail($id);

        return response()->json(['success' => true, 'data' => $contract]);
    }

    /**
     * 계약 생성
     */
    public function store(Request $request): JsonResponse
    {
        $request->validate([
            'title' => 'required|string|max:200',
            'description' => 'nullable|string',
            'sign_order_type' => 'required|in:counterpart_first,creator_first',
            'expires_at' => 'nullable|date',
            'expires_days' => 'nullable|integer|min:1|max:365',
            'signers' => 'required|array|size:2',
            'signers.*.name' => 'required|string|max:100',
            'signers.*.email' => 'required|email|max:200',
            'signers.*.phone' => 'nullable|string|max:20',
            'signers.*.role' => 'required|in:creator,counterpart',
        ]);

        $tenantId = session('selected_tenant_id', 1);
        $userId = auth()->id();

        // 계약 코드 생성
        $contractCode = 'ES-' . date('Ymd') . '-' . strtoupper(Str::random(6));

        // PDF 파일 처리
        $filePath = null;
        $fileName = null;
        $fileHash = null;
        $fileSize = null;

        if ($request->hasFile('file')) {
            $file = $request->file('file');
            $fileName = $file->getClientOriginalName();
            $fileSize = $file->getSize();
            $fileHash = hash_file('sha256', $file->getRealPath());
            $filePath = $file->store("esign/{$tenantId}/contracts", 'local');
        }

        $contract = EsignContract::create([
            'tenant_id' => $tenantId,
            'contract_code' => $contractCode,
            'title' => $request->input('title'),
            'description' => $request->input('description'),
            'sign_order_type' => $request->input('sign_order_type'),
            'original_file_path' => $filePath,
            'original_file_name' => $fileName,
            'original_file_hash' => $fileHash,
            'original_file_size' => $fileSize,
            'status' => 'draft',
            'expires_at' => $request->input('expires_at')
                ? \Carbon\Carbon::parse($request->input('expires_at'))
                : now()->addDays($request->input('expires_days', 30)),
            'created_by' => $userId,
            'updated_by' => $userId,
        ]);

        // 서명자 생성
        $signers = $request->input('signers');
        foreach ($signers as $i => $signerData) {
            EsignSigner::create([
                'tenant_id' => $tenantId,
                'contract_id' => $contract->id,
                'role' => $signerData['role'],
                'sign_order' => $signerData['role'] === 'creator'
                    ? ($request->input('sign_order_type') === 'creator_first' ? 1 : 2)
                    : ($request->input('sign_order_type') === 'counterpart_first' ? 1 : 2),
                'name' => $signerData['name'],
                'email' => $signerData['email'],
                'phone' => $signerData['phone'] ?? null,
                'access_token' => Str::random(128),
                'token_expires_at' => now()->addDays($request->input('expires_days', 30)),
                'status' => 'waiting',
            ]);
        }

        // 감사 로그
        EsignAuditLog::create([
            'tenant_id' => $tenantId,
            'contract_id' => $contract->id,
            'action' => 'contract_created',
            'ip_address' => $request->ip(),
            'user_agent' => $request->userAgent(),
            'metadata' => ['created_by' => $userId],
            'created_at' => now(),
        ]);

        return response()->json([
            'success' => true,
            'message' => '계약이 생성되었습니다.',
            'data' => $contract->load('signers'),
        ]);
    }

    /**
     * 계약 취소
     */
    public function cancel(Request $request, int $id): JsonResponse
    {
        $tenantId = session('selected_tenant_id', 1);
        $contract = EsignContract::forTenant($tenantId)->findOrFail($id);

        if (in_array($contract->status, ['completed', 'cancelled'])) {
            return response()->json(['success' => false, 'message' => '취소할 수 없는 상태입니다.'], 422);
        }

        $contract->update([
            'status' => 'cancelled',
            'updated_by' => auth()->id(),
        ]);

        EsignAuditLog::create([
            'tenant_id' => $tenantId,
            'contract_id' => $contract->id,
            'action' => 'contract_cancelled',
            'ip_address' => $request->ip(),
            'user_agent' => $request->userAgent(),
            'metadata' => ['cancelled_by' => auth()->id()],
            'created_at' => now(),
        ]);

        return response()->json(['success' => true, 'message' => '계약이 취소되었습니다.']);
    }

    /**
     * 서명 위치 설정
     */
    public function configureFields(Request $request, int $id): JsonResponse
    {
        $request->validate([
            'fields' => 'required|array',
            'fields.*.signer_id' => 'required|integer',
            'fields.*.page_number' => 'required|integer|min:1',
            'fields.*.position_x' => 'required|numeric',
            'fields.*.position_y' => 'required|numeric',
            'fields.*.width' => 'required|numeric',
            'fields.*.height' => 'required|numeric',
            'fields.*.field_type' => 'required|in:signature,stamp,text,date,checkbox',
            'fields.*.field_label' => 'nullable|string|max:100',
            'fields.*.is_required' => 'nullable|boolean',
        ]);

        $tenantId = session('selected_tenant_id', 1);
        $contract = EsignContract::forTenant($tenantId)->findOrFail($id);

        // 기존 필드 삭제 후 새로 생성
        EsignSignField::where('contract_id', $contract->id)->delete();

        foreach ($request->input('fields') as $i => $field) {
            EsignSignField::create([
                'tenant_id' => $tenantId,
                'contract_id' => $contract->id,
                'signer_id' => $field['signer_id'],
                'page_number' => $field['page_number'],
                'position_x' => $field['position_x'],
                'position_y' => $field['position_y'],
                'width' => $field['width'],
                'height' => $field['height'],
                'field_type' => $field['field_type'],
                'field_label' => $field['field_label'] ?? null,
                'is_required' => $field['is_required'] ?? true,
                'sort_order' => $i,
            ]);
        }

        return response()->json(['success' => true, 'message' => '서명 위치가 설정되었습니다.']);
    }

    /**
     * 서명 요청 발송 (상태 변경 + 이메일은 추후)
     */
    public function send(Request $request, int $id): JsonResponse
    {
        $tenantId = session('selected_tenant_id', 1);
        $contract = EsignContract::forTenant($tenantId)->with('signers')->findOrFail($id);

        if ($contract->status !== 'draft') {
            return response()->json(['success' => false, 'message' => '초안 상태에서만 발송할 수 있습니다.'], 422);
        }

        $contract->update([
            'status' => 'pending',
            'updated_by' => auth()->id(),
        ]);

        // 서명 순서 유형에 따라 알림 발송
        if ($contract->sign_order_type === 'parallel') {
            // 동시 서명: 모든 서명자에게 발송
            foreach ($contract->signers as $s) {
                $s->update(['status' => 'notified']);
                Mail::to($s->email)->send(new EsignRequestMail($contract, $s));
            }
        } else {
            // 순차 서명: 첫 번째 서명자에게만 발송
            $nextSigner = $contract->signers()->orderBy('sign_order')->first();
            if ($nextSigner) {
                $nextSigner->update(['status' => 'notified']);
                Mail::to($nextSigner->email)->send(new EsignRequestMail($contract, $nextSigner));
            }
        }

        EsignAuditLog::create([
            'tenant_id' => $tenantId,
            'contract_id' => $contract->id,
            'action' => 'sign_request_sent',
            'ip_address' => $request->ip(),
            'user_agent' => $request->userAgent(),
            'metadata' => ['sent_by' => auth()->id()],
            'created_at' => now(),
        ]);

        return response()->json(['success' => true, 'message' => '서명 요청이 발송되었습니다.']);
    }

    /**
     * 리마인더 발송
     */
    public function remind(Request $request, int $id): JsonResponse
    {
        $tenantId = session('selected_tenant_id', 1);
        $contract = EsignContract::forTenant($tenantId)->with('signers')->findOrFail($id);

        if (! in_array($contract->status, ['pending', 'partially_signed'])) {
            return response()->json(['success' => false, 'message' => '리마인더를 발송할 수 없는 상태입니다.'], 422);
        }

        // 다음 서명 대상자 찾기
        $nextSigner = $contract->signers()
            ->whereIn('status', ['waiting', 'notified'])
            ->orderBy('sign_order')
            ->first();

        if ($nextSigner) {
            $nextSigner->update(['status' => 'notified']);
            Mail::to($nextSigner->email)->send(new EsignRequestMail($contract, $nextSigner, isReminder: true));
        }

        EsignAuditLog::create([
            'tenant_id' => $tenantId,
            'contract_id' => $contract->id,
            'action' => 'reminded',
            'ip_address' => $request->ip(),
            'user_agent' => $request->userAgent(),
            'metadata' => [
                'reminded_by' => auth()->id(),
                'target_signer_id' => $nextSigner?->id,
            ],
            'created_at' => now(),
        ]);

        return response()->json([
            'success' => true,
            'message' => $nextSigner
                ? "{$nextSigner->name}에게 리마인더가 발송되었습니다."
                : '리마인더가 기록되었습니다.',
        ]);
    }

    /**
     * PDF 다운로드
     */
    public function download(int $id)
    {
        $tenantId = session('selected_tenant_id', 1);
        $contract = EsignContract::forTenant($tenantId)->findOrFail($id);

        $filePath = $contract->signed_file_path ?: $contract->original_file_path;
        if (! $filePath || ! \Storage::disk('local')->exists($filePath)) {
            abort(404, 'PDF 파일을 찾을 수 없습니다.');
        }

        $fileName = $contract->original_file_name ?: 'contract.pdf';

        return \Storage::disk('local')->download($filePath, $fileName, [
            'Content-Type' => 'application/pdf',
        ]);
    }

    // ─── 필드 템플릿 관련 메서드 ───

    /**
     * 템플릿 목록 조회
     */
    public function indexTemplates(Request $request): JsonResponse
    {
        $tenantId = session('selected_tenant_id', 1);
        $query = EsignFieldTemplate::forTenant($tenantId)
            ->where('is_active', true);

        if ($category = $request->input('category')) {
            $query->where('category', $category);
        }
        if ($search = $request->input('search')) {
            $query->where('name', 'like', "%{$search}%");
        }
        if ($signerCount = $request->input('signer_count')) {
            $query->where('signer_count', $signerCount);
        }

        $templates = $query->withCount('items')->with('creator:id,name')->latest()->get();

        return response()->json(['success' => true, 'data' => $templates]);
    }

    /**
     * 템플릿 저장 (현재 필드를 템플릿으로)
     */
    public function storeTemplate(Request $request): JsonResponse
    {
        $request->validate([
            'name' => 'required|string|max:100',
            'description' => 'nullable|string',
            'category' => 'nullable|string|max:50',
            'items' => 'required|array|min:1',
            'items.*.signer_order' => 'required|integer|min:1',
            'items.*.page_number' => 'required|integer|min:1',
            'items.*.position_x' => 'required|numeric',
            'items.*.position_y' => 'required|numeric',
            'items.*.width' => 'required|numeric',
            'items.*.height' => 'required|numeric',
            'items.*.field_type' => 'required|in:signature,stamp,text,date,checkbox',
            'items.*.field_label' => 'nullable|string|max:100',
            'items.*.is_required' => 'nullable|boolean',
        ]);

        $tenantId = session('selected_tenant_id', 1);

        // items에서 최대 signer_order를 추출하여 signer_count 결정
        $items = $request->input('items');
        $signerCount = max(array_column($items, 'signer_order'));

        $template = DB::transaction(function () use ($tenantId, $request, $items, $signerCount) {
            $template = EsignFieldTemplate::create([
                'tenant_id' => $tenantId,
                'name' => $request->input('name'),
                'description' => $request->input('description'),
                'category' => $request->input('category'),
                'signer_count' => $signerCount,
                'is_active' => true,
                'created_by' => auth()->id(),
            ]);

            foreach ($items as $i => $item) {
                EsignFieldTemplateItem::create([
                    'template_id' => $template->id,
                    'signer_order' => $item['signer_order'],
                    'page_number' => $item['page_number'],
                    'position_x' => $item['position_x'],
                    'position_y' => $item['position_y'],
                    'width' => $item['width'],
                    'height' => $item['height'],
                    'field_type' => $item['field_type'],
                    'field_label' => $item['field_label'] ?? null,
                    'is_required' => $item['is_required'] ?? true,
                    'sort_order' => $i,
                ]);
            }

            return $template;
        });

        return response()->json([
            'success' => true,
            'message' => '필드 템플릿이 저장되었습니다.',
            'data' => $template->load('items'),
        ]);
    }

    /**
     * 템플릿 단건 조회
     */
    public function showTemplate(int $id): JsonResponse
    {
        $tenantId = session('selected_tenant_id', 1);
        $template = EsignFieldTemplate::forTenant($tenantId)
            ->where('is_active', true)
            ->with(['items', 'creator:id,name'])
            ->findOrFail($id);

        return response()->json(['success' => true, 'data' => $template]);
    }

    /**
     * 템플릿 메타데이터 수정
     */
    public function updateTemplate(Request $request, int $id): JsonResponse
    {
        $request->validate([
            'name' => 'required|string|max:100',
            'description' => 'nullable|string',
            'category' => 'nullable|string|max:50',
        ]);

        $tenantId = session('selected_tenant_id', 1);
        $template = EsignFieldTemplate::forTenant($tenantId)->findOrFail($id);

        $template->update([
            'name' => $request->input('name'),
            'description' => $request->input('description'),
            'category' => $request->input('category'),
        ]);

        return response()->json([
            'success' => true,
            'message' => '템플릿이 수정되었습니다.',
            'data' => $template->fresh()->load('creator:id,name'),
        ]);
    }

    /**
     * 템플릿 복제
     */
    public function duplicateTemplate(int $id): JsonResponse
    {
        $tenantId = session('selected_tenant_id', 1);
        $template = EsignFieldTemplate::forTenant($tenantId)
            ->where('is_active', true)
            ->with('items')
            ->findOrFail($id);

        $newTemplate = DB::transaction(function () use ($template, $tenantId) {
            $newTemplate = EsignFieldTemplate::create([
                'tenant_id' => $tenantId,
                'name' => $template->name . ' (복사)',
                'description' => $template->description,
                'category' => $template->category,
                'signer_count' => $template->signer_count,
                'is_active' => true,
                'created_by' => auth()->id(),
            ]);

            foreach ($template->items as $item) {
                EsignFieldTemplateItem::create([
                    'template_id' => $newTemplate->id,
                    'signer_order' => $item->signer_order,
                    'page_number' => $item->page_number,
                    'position_x' => $item->position_x,
                    'position_y' => $item->position_y,
                    'width' => $item->width,
                    'height' => $item->height,
                    'field_type' => $item->field_type,
                    'field_label' => $item->field_label,
                    'is_required' => $item->is_required,
                    'sort_order' => $item->sort_order,
                ]);
            }

            return $newTemplate;
        });

        return response()->json([
            'success' => true,
            'message' => '템플릿이 복제되었습니다.',
            'data' => $newTemplate->load(['items', 'creator:id,name'])->loadCount('items'),
        ]);
    }

    /**
     * 템플릿 삭제 (soft: is_active=false)
     */
    public function destroyTemplate(int $id): JsonResponse
    {
        $tenantId = session('selected_tenant_id', 1);
        $template = EsignFieldTemplate::forTenant($tenantId)->findOrFail($id);

        $template->update(['is_active' => false]);

        return response()->json(['success' => true, 'message' => '템플릿이 삭제되었습니다.']);
    }

    /**
     * 템플릿을 계약에 적용
     */
    public function applyTemplate(Request $request, int $id): JsonResponse
    {
        $request->validate([
            'template_id' => 'required|integer',
        ]);

        $tenantId = session('selected_tenant_id', 1);
        $contract = EsignContract::forTenant($tenantId)->with('signers')->findOrFail($id);
        $template = EsignFieldTemplate::forTenant($tenantId)
            ->where('is_active', true)
            ->with('items')
            ->findOrFail($request->input('template_id'));

        // 서명자 수 확인
        $contractSignerCount = $contract->signers->count();
        if ($template->signer_count > $contractSignerCount) {
            return response()->json([
                'success' => false,
                'message' => "템플릿에 필요한 서명자 수({$template->signer_count}명)가 계약의 서명자 수({$contractSignerCount}명)보다 많습니다.",
            ], 422);
        }

        // signer_order → signer_id 매핑
        $signerMap = [];
        foreach ($contract->signers as $signer) {
            $signerMap[$signer->sign_order] = $signer->id;
        }

        DB::transaction(function () use ($contract, $template, $tenantId, $signerMap) {
            // 기존 필드 삭제
            EsignSignField::where('contract_id', $contract->id)->delete();

            // 템플릿 아이템 → 필드 생성
            foreach ($template->items as $item) {
                $signerId = $signerMap[$item->signer_order] ?? null;
                if (!$signerId) continue;

                EsignSignField::create([
                    'tenant_id' => $tenantId,
                    'contract_id' => $contract->id,
                    'signer_id' => $signerId,
                    'page_number' => $item->page_number,
                    'position_x' => $item->position_x,
                    'position_y' => $item->position_y,
                    'width' => $item->width,
                    'height' => $item->height,
                    'field_type' => $item->field_type,
                    'field_label' => $item->field_label,
                    'is_required' => $item->is_required,
                    'sort_order' => $item->sort_order,
                ]);
            }
        });

        $fields = EsignSignField::where('contract_id', $contract->id)->orderBy('sort_order')->get();

        return response()->json([
            'success' => true,
            'message' => '템플릿이 적용되었습니다.',
            'data' => $fields,
        ]);
    }

    /**
     * 다른 계약에서 필드 복사
     */
    public function copyFieldsFromContract(Request $request, int $id, int $sourceId): JsonResponse
    {
        $tenantId = session('selected_tenant_id', 1);
        $targetContract = EsignContract::forTenant($tenantId)->with('signers')->findOrFail($id);
        $sourceContract = EsignContract::forTenant($tenantId)->with(['signers', 'signFields'])->findOrFail($sourceId);

        if ($sourceContract->signFields->isEmpty()) {
            return response()->json([
                'success' => false,
                'message' => '소스 계약에 복사할 필드가 없습니다.',
            ], 422);
        }

        // 소스 계약 서명자의 sign_order → signer_id 매핑
        $sourceSignerOrderMap = [];
        foreach ($sourceContract->signers as $signer) {
            $sourceSignerOrderMap[$signer->id] = $signer->sign_order;
        }

        // 대상 계약 sign_order → signer_id 매핑
        $targetSignerMap = [];
        foreach ($targetContract->signers as $signer) {
            $targetSignerMap[$signer->sign_order] = $signer->id;
        }

        DB::transaction(function () use ($targetContract, $sourceContract, $tenantId, $sourceSignerOrderMap, $targetSignerMap) {
            // 기존 필드 삭제
            EsignSignField::where('contract_id', $targetContract->id)->delete();

            foreach ($sourceContract->signFields as $field) {
                // 소스 signer_id → sign_order → 대상 signer_id
                $signOrder = $sourceSignerOrderMap[$field->signer_id] ?? null;
                $targetSignerId = $signOrder ? ($targetSignerMap[$signOrder] ?? null) : null;
                if (!$targetSignerId) continue;

                EsignSignField::create([
                    'tenant_id' => $tenantId,
                    'contract_id' => $targetContract->id,
                    'signer_id' => $targetSignerId,
                    'page_number' => $field->page_number,
                    'position_x' => $field->position_x,
                    'position_y' => $field->position_y,
                    'width' => $field->width,
                    'height' => $field->height,
                    'field_type' => $field->field_type,
                    'field_label' => $field->field_label,
                    'is_required' => $field->is_required,
                    'sort_order' => $field->sort_order,
                ]);
            }
        });

        $fields = EsignSignField::where('contract_id', $targetContract->id)->orderBy('sort_order')->get();

        return response()->json([
            'success' => true,
            'message' => '필드가 복사되었습니다.',
            'data' => $fields,
        ]);
    }
}