'use client';

import { useState, useEffect, useCallback } from 'react';
import { Shield, Edit, Users, Check, X, Plus } from 'lucide-react';
import { positionsAPI } from '@/lib/api/admin';
import { departmentsAPI } from '@/lib/api/employees';
import type { PositionRole, PositionPermission, CreatePositionData } from '@/lib/api/admin';
import Modal from '@/components/Modal';
import LoadingSpinner from '@/components/LoadingSpinner';

const MODULES = [
  { id: 'contacts', name: 'إدارة جهات الاتصال', nameEn: 'Contact Management' },
  { id: 'suppliers', name: 'إدارة الموردين', nameEn: 'Supplier Management' },
  { id: 'crm', name: 'إدارة علاقات العملاء', nameEn: 'CRM' },
  { id: 'tenders', name: 'إدارة المناقصات', nameEn: 'Tender Management' },
  { id: 'inventory', name: 'المخزون والأصول', nameEn: 'Inventory & Assets' },
  { id: 'projects', name: 'المهام والمشاريع', nameEn: 'Tasks & Projects' },

  { id: 'hr', name: 'الموارد البشرية', nameEn: 'HR Management' },

  { id: 'leave_requests', name: 'طلبات الإجازات', nameEn: 'Leave Requests' },
  { id: 'overtime_requests', name: 'طلبات الساعات الإضافية', nameEn: 'Overtime Requests' },
  { id: 'loan_requests', name: 'طلبات القروض', nameEn: 'Loan Requests' },
  { id: 'purchase_requests', name: 'طلبات الشراء', nameEn: 'Purchase Requests' },

  { id: 'department_leave_requests', name: 'طلبات إجازات القسم', nameEn: 'Department Leave Requests' },
  { id: 'department_overtime_requests', name: 'طلبات الساعات الإضافية للقسم', nameEn: 'Department Overtime Requests' },
  { id: 'department_expense_claims', name: 'طلبات كشف المصاريف للقسم', nameEn: 'Department Expense Claims' },

  { id: 'portal', name: 'البوابة الذاتية', nameEn: 'My Portal' },
  { id: 'marketing', name: 'التسويق', nameEn: 'Marketing' },
  { id: 'admin', name: 'لوحة الإدارة', nameEn: 'Admin' },
];

const ACTIONS = [
  { id: 'read', name: 'عرض' },
  { id: 'create', name: 'إنشاء' },
  { id: 'update', name: 'تعديل' },
  { id: 'delete', name: 'حذف' },
  { id: 'export', name: 'تصدير' },
  { id: 'approve', name: 'اعتماد' },
  { id: 'mark-as-paid', name: 'تأكيد القبض' },
  { id: 'notify', name: 'إشعار' },
  { id: 'merge', name: 'دمج' },
];

function hasAction(permission: PositionPermission | undefined, action: string): boolean {
  if (!permission?.actions) return false;
  const actions = Array.isArray(permission.actions) ? permission.actions : [];
  return actions.includes('*') || actions.includes('all') || actions.includes(action);
}

function buildPermissionsFromMatrix(matrix: Record<string, Record<string, boolean>>) {
  return MODULES.filter((m) => Object.values(matrix[m.id] || {}).some(Boolean)).map((m) => {
    const actions = ACTIONS.filter((a) => matrix[m.id]?.[a.id]).map((a) => a.id);
    return {
      module: m.id,
      resource: '*',
      actions: actions.length === ACTIONS.length ? ['*'] : actions,
    };
  });
}

function buildMatrixFromPermissions(permissions: PositionPermission[]): Record<string, Record<string, boolean>> {
  const matrix: Record<string, Record<string, boolean>> = {};
  for (const m of MODULES) {
    matrix[m.id] = {};
    const perm = permissions.find((p) => p.module === m.id && (p.resource === '*' || p.resource === m.id));
    const hasAll = perm && (Array.isArray(perm.actions)
      ? (perm.actions as string[]).includes('*') || (perm.actions as string[]).includes('all')
      : false);
    for (const a of ACTIONS) {
      matrix[m.id][a.id] = hasAll || hasAction(perm, a.id);
    }
  }
  return matrix;
}

const initialCreateForm: CreatePositionData & { description?: string } = {
  title: '',
  titleAr: '',
  code: '',
  departmentId: '',
  level: 5,
  description: '',
};

export default function RolesManagement() {
  const [roles, setRoles] = useState<PositionRole[]>([]);
  const [departments, setDepartments] = useState<{ id: string; name: string; nameAr?: string | null }[]>([]);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);
  const [selectedRoleId, setSelectedRoleId] = useState<string | null>(null);
  const [showEditModal, setShowEditModal] = useState(false);
  const [showCreateModal, setShowCreateModal] = useState(false);
  const [createForm, setCreateForm] = useState(initialCreateForm);
  const [createErrors, setCreateErrors] = useState<Record<string, string>>({});
  const [permissionMatrix, setPermissionMatrix] = useState<Record<string, Record<string, boolean>>>({});
  const [saving, setSaving] = useState(false);

  const fetchRoles = useCallback(async () => {
    setLoading(true);
    setError(null);
    try {
      const pos = await positionsAPI.getAll();
      setRoles(pos);
      if (selectedRoleId && !pos.find((p) => p.id === selectedRoleId)) {
        setSelectedRoleId(null);
      }
    } catch (err: unknown) {
      setError(err instanceof Error ? err.message : 'فشل تحميل الأدوار');
    } finally {
      setLoading(false);
    }
  }, [selectedRoleId]);

  useEffect(() => {
    fetchRoles();
  }, [fetchRoles]);

  useEffect(() => {
    departmentsAPI.getAll().then((depts) => setDepartments(depts)).catch(() => {});
  }, []);

  const currentRole = roles.find((r) => r.id === selectedRoleId);

  const handleCreateRole = async (e: React.FormEvent) => {
    e.preventDefault();
    const errs: Record<string, string> = {};
    if (!createForm.title?.trim()) errs.title = 'Required';
    if (!createForm.code?.trim()) errs.code = 'Required';
    if (!createForm.departmentId) errs.departmentId = 'Required';
    setCreateErrors(errs);
    if (Object.keys(errs).length > 0) return;

    setSaving(true);
    try {
      const position = await positionsAPI.create({
        title: createForm.title.trim(),
        titleAr: createForm.titleAr?.trim() || undefined,
        code: createForm.code.trim(),
        departmentId: createForm.departmentId,
        level: createForm.level ?? 5,
        description: createForm.description?.trim() || undefined,
      });
      setShowCreateModal(false);
      setCreateForm(initialCreateForm);
      setCreateErrors({});
      await fetchRoles();
      setSelectedRoleId(position.id);
      setShowEditModal(true);
    } catch (err: unknown) {
      setCreateErrors({ form: err instanceof Error ? err.message : 'Failed to create role' });
    } finally {
      setSaving(false);
    }
  };

  useEffect(() => {
    if (currentRole) {
      setPermissionMatrix(buildMatrixFromPermissions(currentRole.permissions || []));
    }
  }, [currentRole?.id, currentRole?.permissions]);

  const handleTogglePermission = (moduleId: string, actionId: string) => {
    setPermissionMatrix((prev) => ({
      ...prev,
      [moduleId]: {
        ...(prev[moduleId] || {}),
        [actionId]: !prev[moduleId]?.[actionId],
      },
    }));
  };

  const handleSavePermissions = async () => {
    if (!selectedRoleId) return;
    setSaving(true);
    try {
      const permissions = buildPermissionsFromMatrix(permissionMatrix);
      await positionsAPI.updatePermissions(selectedRoleId, permissions);
      setShowEditModal(false);
      fetchRoles();
    } catch (err: unknown) {
      alert(err instanceof Error ? err.message : 'فشل حفظ الصلاحيات');
    } finally {
      setSaving(false);
    }
  };

  const handleSelectRole = (id: string) => {
    setSelectedRoleId(id);
    setShowEditModal(false);
  };

  return (
    <div>
      <div className="mb-8 flex items-center justify-between">
        <div>
          <h1 className="text-3xl font-bold text-gray-900 mb-2">الأدوار والصلاحيات</h1>
          <p className="text-gray-600">إدارة أدوار المستخدمين ومصفوفة الصلاحيات</p>
        </div>
        <button
          onClick={() => setShowCreateModal(true)}
          className="flex items-center gap-2 px-6 py-3 bg-purple-600 text-white rounded-lg hover:bg-purple-700 transition-all shadow-md hover:shadow-lg"
        >
          <Plus className="h-5 w-5" />
          <span className="font-semibold">إضافة دور</span>
        </button>
      </div>

      {loading ? (
        <div className="flex justify-center p-12">
          <LoadingSpinner />
        </div>
      ) : error ? (
        <div className="text-center text-red-600 p-12">{error}</div>
      ) : (
        <div className="grid grid-cols-1 lg:grid-cols-3 gap-8">
          {/* Roles List */}
          <div className="lg:col-span-1 space-y-4">
            <h2 className="text-xl font-bold text-gray-900 mb-4">الأدوار ({roles.length})</h2>

            {roles.map((role) => (
              <div
                key={role.id}
                onClick={() => handleSelectRole(role.id)}
                className={`p-4 rounded-xl border-2 cursor-pointer transition-all ${
                  selectedRoleId === role.id
                    ? 'border-purple-600 bg-purple-50 shadow-md'
                    : 'border-gray-200 bg-white hover:border-purple-300 hover:shadow-sm'
                }`}
              >
                <div className="flex items-start justify-between mb-2">
                  <div className="flex items-center gap-3">
                    <div
                      className={`p-2 rounded-lg ${selectedRoleId === role.id ? 'bg-purple-600' : 'bg-purple-100'}`}
                    >
                      <Shield
                        className={`h-5 w-5 ${selectedRoleId === role.id ? 'text-white' : 'text-purple-600'}`}
                      />
                    </div>
                    <div>
                      <h3 className="font-bold text-gray-900">{role.titleAr || role.title}</h3>
                      <p className="text-xs text-gray-600">{role.title}</p>
                    </div>
                  </div>
                </div>
                <div className="flex items-center justify-between">
                  <div className="flex items-center gap-2 text-sm text-gray-600">
                    <Users className="h-4 w-4" />
                    <span>{role.usersCount ?? role._count?.employees ?? 0} مستخدم</span>
                  </div>
                  <button
                    onClick={(e) => {
                      e.stopPropagation();
                      setSelectedRoleId(role.id);
                      setShowEditModal(true);
                    }}
                    className="p-1.5 text-blue-600 hover:bg-blue-50 rounded transition-colors"
                  >
                    <Edit className="h-4 w-4" />
                  </button>
                </div>
              </div>
            ))}
          </div>

          {/* Permission Matrix */}
          <div className="lg:col-span-2">
            {currentRole ? (
              <div className="bg-white rounded-xl shadow-lg border border-gray-200">
                <div className="p-6 border-b border-gray-200">
                  <div className="flex items-center justify-between">
                    <div>
                      <h2 className="text-2xl font-bold text-gray-900">{currentRole.titleAr || currentRole.title}</h2>
                      <p className="text-gray-600">{currentRole.title}</p>
                    </div>
                    <button
                      onClick={() => setShowEditModal(true)}
                      className="px-4 py-2 bg-purple-600 text-white rounded-lg hover:bg-purple-700 transition-colors font-medium"
                    >
                      تعديل الصلاحيات
                    </button>
                  </div>
                </div>
                <div className="p-6">
                  <h3 className="text-lg font-bold text-gray-900 mb-4">مصفوفة الصلاحيات</h3>
                  <div className="overflow-x-auto">
                    <table className="w-full">
                      <thead>
                        <tr className="border-b-2 border-gray-200">
                          <th className="px-4 py-3 text-right text-sm font-bold text-gray-900 min-w-[200px]">
                            الوحدة
                          </th>
                          {ACTIONS.map((perm) => (
                            <th key={perm.id} className="px-4 py-3 text-center text-sm font-bold text-gray-900">
                              {perm.name}
                            </th>
                          ))}
                        </tr>
                      </thead>
                      <tbody className="divide-y divide-gray-200">
                        {MODULES.map((module) => (
                          <tr key={module.id} className="hover:bg-gray-50 transition-colors">
                            <td className="px-4 py-4">
                              <div>
                                <p className="font-semibold text-gray-900">{module.name}</p>
                                <p className="text-xs text-gray-600">{module.nameEn}</p>
                              </div>
                            </td>
                            {ACTIONS.map((action) => {
                              const hasPermission = permissionMatrix[module.id]?.[action.id];
                              return (
                                <td key={action.id} className="px-4 py-4 text-center">
                                  <div
                                    className={`w-10 h-10 rounded-lg flex items-center justify-center transition-all mx-auto ${
                                      hasPermission
                                        ? 'bg-green-500 text-white shadow-md'
                                        : 'bg-gray-200 text-gray-500'
                                    }`}
                                  >
                                    {hasPermission ? <Check className="h-6 w-6" /> : <X className="h-6 w-6" />}
                                  </div>
                                </td>
                              );
                            })}
                          </tr>
                        ))}
                      </tbody>
                    </table>
                  </div>
                </div>
              </div>
            ) : (
              <div className="bg-white rounded-xl shadow-lg border border-gray-200 p-12 text-center">
                <Shield className="h-16 w-16 text-gray-300 mx-auto mb-4" />
                <h3 className="text-xl font-bold text-gray-900 mb-2">اختر دوراً لعرض الصلاحيات</h3>
                <p className="text-gray-600">اختر دور من القائمة لعرض وتعديل صلاحياته</p>
              </div>
            )}
          </div>
        </div>
      )}

      {/* Create Role Modal */}
      <Modal
        isOpen={showCreateModal}
        onClose={() => {
          setShowCreateModal(false);
          setCreateForm(initialCreateForm);
          setCreateErrors({});
        }}
        title="إضافة دور جديد"
        size="md"
      >
        <form onSubmit={handleCreateRole} className="space-y-4">
          <div>
            <label className="block text-sm font-medium text-gray-700 mb-1">Title (English) *</label>
            <input
              type="text"
              value={createForm.title}
              onChange={(e) => setCreateForm((p) => ({ ...p, title: e.target.value }))}
              className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-purple-500"
              placeholder="e.g. Sales Representative"
            />
            {createErrors.title && <p className="text-red-500 text-xs mt-1">{createErrors.title}</p>}
          </div>
          <div>
            <label className="block text-sm font-medium text-gray-700 mb-1">Title (Arabic)</label>
            <input
              type="text"
              value={createForm.titleAr || ''}
              onChange={(e) => setCreateForm((p) => ({ ...p, titleAr: e.target.value }))}
              className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-purple-500"
              placeholder="مندوب مبيعات"
            />
          </div>
          <div>
            <label className="block text-sm font-medium text-gray-700 mb-1">Code *</label>
            <input
              type="text"
              value={createForm.code}
              onChange={(e) => setCreateForm((p) => ({ ...p, code: e.target.value }))}
              className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-purple-500"
              placeholder="SALES_REP"
            />
            {createErrors.code && <p className="text-red-500 text-xs mt-1">{createErrors.code}</p>}
          </div>
          <div>
            <label className="block text-sm font-medium text-gray-700 mb-1">Department *</label>
            <select
              value={createForm.departmentId}
              onChange={(e) => setCreateForm((p) => ({ ...p, departmentId: e.target.value }))}
              className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-purple-500"
            >
              <option value="">Select department</option>
              {departments.map((d) => (
                <option key={d.id} value={d.id}>{d.nameAr || d.name}</option>
              ))}
            </select>
            {createErrors.departmentId && <p className="text-red-500 text-xs mt-1">{createErrors.departmentId}</p>}
          </div>
          <div>
            <label className="block text-sm font-medium text-gray-700 mb-1">Level</label>
            <input
              type="number"
              min={1}
              value={createForm.level ?? 5}
              onChange={(e) => setCreateForm((p) => ({ ...p, level: parseInt(e.target.value, 10) || 5 }))}
              className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-purple-500"
            />
          </div>
          <div>
            <label className="block text-sm font-medium text-gray-700 mb-1">Description</label>
            <textarea
              value={createForm.description || ''}
              onChange={(e) => setCreateForm((p) => ({ ...p, description: e.target.value }))}
              className="w-full px-3 py-2 border border-gray-300 rounded-lg focus:ring-2 focus:ring-purple-500"
              rows={2}
              placeholder="Optional description"
            />
          </div>
          {createErrors.form && <p className="text-red-500 text-sm">{createErrors.form}</p>}
          <div className="flex gap-3 justify-end pt-4">
            <button
              type="button"
              onClick={() => setShowCreateModal(false)}
              className="px-6 py-3 border border-gray-300 text-gray-700 rounded-lg hover:bg-gray-50 font-medium"
            >
              Cancel
            </button>
            <button
              type="submit"
              disabled={saving}
              className="px-6 py-3 bg-purple-600 text-white rounded-lg hover:bg-purple-700 font-semibold disabled:opacity-50"
            >
              {saving ? 'Creating...' : 'Create Role'}
            </button>
          </div>
        </form>
      </Modal>

      {/* Edit Permissions Modal */}
      <Modal
        isOpen={showEditModal}
        onClose={() => setShowEditModal(false)}
        title={`تعديل صلاحيات: ${currentRole?.titleAr || currentRole?.title || ''}`}
        size="2xl"
      >
        {currentRole && (
          <div>
            <div className="overflow-x-auto mb-6">
              <table className="w-full">
                <thead>
                  <tr className="border-b-2 border-gray-200">
                    <th className="px-4 py-3 text-right text-sm font-bold text-gray-900">الوحدة</th>
                    {ACTIONS.map((perm) => (
                      <th key={perm.id} className="px-4 py-3 text-center text-sm font-bold text-gray-900">
                        {perm.name}
                      </th>
                    ))}
                  </tr>
                </thead>
                <tbody className="divide-y divide-gray-200">
                  {MODULES.map((module) => (
                    <tr key={module.id}>
                      <td className="px-4 py-4">
                        <p className="font-semibold text-gray-900">{module.name}</p>
                      </td>
                      {ACTIONS.map((action) => {
                        const hasPermission = permissionMatrix[module.id]?.[action.id];
                        return (
                          <td key={action.id} className="px-4 py-4 text-center">
                            <button
                              type="button"
                              onClick={() => handleTogglePermission(module.id, action.id)}
                              className={`w-10 h-10 rounded-lg flex items-center justify-center transition-all mx-auto ${
                                hasPermission ? 'bg-green-500 text-white' : 'bg-gray-200 text-gray-500'
                              }`}
                            >
                              {hasPermission ? <Check className="h-6 w-6" /> : <X className="h-6 w-6" />}
                            </button>
                          </td>
                        );
                      })}
                    </tr>
                  ))}
                </tbody>
              </table>
            </div>
            <div className="flex gap-3 justify-end">
              <button
                onClick={() => setShowEditModal(false)}
                className="px-6 py-3 border border-gray-300 text-gray-700 rounded-lg hover:bg-gray-50 font-medium"
              >
                إلغاء
              </button>
              <button
                onClick={handleSavePermissions}
                disabled={saving}
                className="px-6 py-3 bg-purple-600 text-white rounded-lg hover:bg-purple-700 font-semibold disabled:opacity-50"
              >
                {saving ? 'جاري الحفظ...' : 'حفظ التغييرات'}
              </button>
            </div>
          </div>
        )}
      </Modal>
    </div>
  );
}