'use client';

import { useState } from 'react';
import { Shield, Plus, Search, X, Edit, Trash2, Copy, Check, ChevronDown, ChevronRight, BookOpen, FileSearch, ClipboardList, Settings, BarChart3, Bike, Users, Briefcase, Truck, Store, BatteryCharging, Building2, Wrench, DollarSign, TrendingUp, UserCog } from 'lucide-react';

interface Permission {
  key: string;
  label: string;
  enabled: boolean;
}

interface PermissionGroup {
  id: string;
  title: string;
  description: string;
  icon: React.ComponentType<{ className?: string }>;
  permissions: Permission[];
}

interface Role {
  id: string;
  name: string;
  description: string;
  isDefault: boolean;
  permissionGroups: PermissionGroup[];
}

const buildDefaultGroups = (): PermissionGroup[] => [

  {
    id: 'kyc',
    title: 'KYC Requests & Verification',
    description: 'The Biker user will request from the app. Investor, Shop, Merchant will request from the website. Front desk officers (hub/head office) can request for Biker, Investor, Shop, Merchant and can upload remaining documents. Admin officers (head office) will approve or reject documents with notes and "make a Biker | Investor | Shop | Merchant".',
    icon: FileSearch,
    permissions: [
      { key: 'kyc.request', label: 'KYC Request', enabled: false },
      { key: 'kyc.view', label: 'View KYC Requests', enabled: false },
      { key: 'kyc.doc_upload', label: 'Document Upload', enabled: false },
      { key: 'kyc.doc_approve', label: 'Document Approve', enabled: false },
      { key: 'kyc.doc_reject', label: 'Document Reject', enabled: false },
      { key: 'kyc.make_valid_user', label: 'Make a Biker | Investor | Shop | Merchant', enabled: false },
    ]
  },
  {
    id: 'plans',
    title: 'Plan Selection + EV Condition',
    description: 'Manage investment plans, swap station plans, and rider request plans',
    icon: ClipboardList,
    permissions: [
      { key: 'plans.investment.view', label: 'View Investment Plan', enabled: false },
      { key: 'plans.investment.edit', label: 'Edit Investment Plan', enabled: false },
      { key: 'plans.swap_station.view', label: 'View Swap Station Plan', enabled: false },
      { key: 'plans.swap_station.edit', label: 'Edit Swap Station Plan', enabled: false },
      { key: 'plans.rider_request.view', label: 'View Rider Request Plan', enabled: false },
      { key: 'plans.rider_request.edit', label: 'Edit Rider Request Plan', enabled: false },
    ]
  },
  {
    id: 'settings',
    title: 'Settings',
    description: 'Manage system settings including KYC documents and plans',
    icon: Settings,
    permissions: [
      { key: 'settings.kyc_documents.view', label: 'View KYC Documents', enabled: false },
      { key: 'settings.kyc_documents.edit', label: 'Edit KYC Documents', enabled: false },
      { key: 'settings.plan_selection.view', label: 'View Plan Selection with Condition', enabled: false },
      { key: 'settings.plan_selection.edit', label: 'Edit Plan Selection with Condition', enabled: false },
      { key: 'settings.company_policy.view', label: 'View Company Policy', enabled: false },
      { key: 'settings.company_policy.edit', label: 'Edit Company Policy', enabled: false },
    ]
  },
  {
    id: 'dashboard',
    title: 'Dashboard',
    description: 'Access to main dashboard',
    icon: BarChart3,
    permissions: [
      { key: 'dashboard.view', label: 'View Dashboard', enabled: false },
    ]
  },
  {
    id: 'rentals',
    title: 'Rentals',
    description: 'Manage rental operations',
    icon: Bike,
    permissions: [
      { key: 'rentals.view', label: 'View', enabled: false },
      { key: 'rentals.create', label: 'Create', enabled: false },
      { key: 'rentals.edit', label: 'Edit', enabled: false },
      { key: 'rentals.delete', label: 'Delete', enabled: false },
    ]
  },
  {
    id: 'bikers',
    title: 'Bikers',
    description: 'Manage bikers',
    icon: Users,
    permissions: [
      { key: 'bikers.view', label: 'View', enabled: false },
      { key: 'bikers.create', label: 'Create', enabled: false },
      { key: 'bikers.edit', label: 'Edit', enabled: false },
      { key: 'bikers.delete', label: 'Delete', enabled: false },
    ]
  },
  {
    id: 'investors',
    title: 'Investors',
    description: 'Manage investors',
    icon: Briefcase,
    permissions: [
      { key: 'investors.view', label: 'View', enabled: false },
      { key: 'investors.create', label: 'Create', enabled: false },
      { key: 'investors.edit', label: 'Edit', enabled: false },
      { key: 'investors.delete', label: 'Delete', enabled: false },
    ]
  },
  {
    id: 'fleet',
    title: 'Fleet',
    description: 'Manage fleet vehicles',
    icon: Truck,
    permissions: [
      { key: 'fleet.view', label: 'View', enabled: false },
      { key: 'fleet.create', label: 'Create', enabled: false },
      { key: 'fleet.edit', label: 'Edit', enabled: false },
      { key: 'fleet.delete', label: 'Delete', enabled: false },
    ]
  },
  {
    id: 'merchants',
    title: 'Merchants',
    description: 'Manage merchants',
    icon: Store,
    permissions: [
      { key: 'merchants.view', label: 'View', enabled: false },
      { key: 'merchants.create', label: 'Create', enabled: false },
      { key: 'merchants.edit', label: 'Edit', enabled: false },
      { key: 'merchants.delete', label: 'Delete', enabled: false },
    ]
  },
  {
    id: 'swap_stations',
    title: 'Swap Stations',
    description: 'Manage swap stations',
    icon: BatteryCharging,
    permissions: [
      { key: 'swap_stations.view', label: 'View', enabled: false },
      { key: 'swap_stations.create', label: 'Create', enabled: false },
      { key: 'swap_stations.edit', label: 'Edit', enabled: false },
      { key: 'swap_stations.delete', label: 'Delete', enabled: false },
    ]
  },
  {
    id: 'hubs',
    title: 'Hubs',
    description: 'Manage hubs',
    icon: Building2,
    permissions: [
      { key: 'hubs.view', label: 'View', enabled: false },
      { key: 'hubs.create', label: 'Create', enabled: false },
      { key: 'hubs.edit', label: 'Edit', enabled: false },
      { key: 'hubs.delete', label: 'Delete', enabled: false },
    ]
  },
  {
    id: 'maintenance',
    title: 'Maintenance',
    description: 'Manage maintenance requests',
    icon: Wrench,
    permissions: [
      { key: 'maintenance.view', label: 'View', enabled: false },
      { key: 'maintenance.create', label: 'Create', enabled: false },
      { key: 'maintenance.edit', label: 'Edit', enabled: false },
      { key: 'maintenance.delete', label: 'Delete', enabled: false },
    ]
  },
  {
    id: 'accounting',
    title: 'Accounting',
    description: 'Manage financial records',
    icon: DollarSign,
    permissions: [
      { key: 'accounting.view', label: 'View', enabled: false },
      { key: 'accounting.create', label: 'Create', enabled: false },
      { key: 'accounting.edit', label: 'Edit', enabled: false },
      { key: 'accounting.delete', label: 'Delete', enabled: false },
    ]
  },
  {
    id: 'reports',
    title: 'Reports',
    description: 'View and generate reports',
    icon: TrendingUp,
    permissions: [
      { key: 'reports.view', label: 'View', enabled: false },
      { key: 'reports.export', label: 'Export', enabled: false },
    ]
  },
  {
    id: 'users',
    title: 'Users',
    description: 'Manage system users',
    icon: UserCog,
    permissions: [
      { key: 'users.view', label: 'View', enabled: false },
      { key: 'users.create', label: 'Create', enabled: false },
      { key: 'users.edit', label: 'Edit', enabled: false },
      { key: 'users.delete', label: 'Delete', enabled: false },
    ]
  },
];

const mockRoles: Role[] = [
  {
    id: 'ROLE-001',
    name: 'Admin',
    description: 'Full system access with all permissions',
    isDefault: false,
    permissionGroups: buildDefaultGroups().map(g => ({
      ...g,
      permissions: g.permissions.map(p => ({ ...p, enabled: true }))
    }))
  },
  {
    id: 'ROLE-002',
    name: 'Manager',
    description: 'Management access with limited delete permissions',
    isDefault: false,
    permissionGroups: buildDefaultGroups().map(g => ({
      ...g,
      permissions: g.permissions.map(p => ({
        ...p,
        enabled: !p.key.includes('delete')
      }))
    }))
  },
  {
    id: 'ROLE-003',
    name: 'Front Desk Officer',
    description: 'Hub/head office officer - can request KYC and upload documents',
    isDefault: false,
    permissionGroups: buildDefaultGroups().map(g => {
      if (g.id === 'kyc') {
        return {
          ...g,
          permissions: g.permissions.map(p => ({
            ...p,
            enabled: ['kyc.request', 'kyc.view', 'kyc.doc_upload'].includes(p.key)
          }))
        };
      }
      if (g.id === 'dashboard') {
        return { ...g, permissions: g.permissions.map(p => ({ ...p, enabled: true })) };
      }
      return g;
    })
  },
  {
    id: 'ROLE-004',
    name: 'Admin Officer',
    description: 'Head office officer - can approve/reject KYC documents and make valid users',
    isDefault: false,
    permissionGroups: buildDefaultGroups().map(g => {
      if (g.id === 'kyc') {
        return {
          ...g,
          permissions: g.permissions.map(p => ({
            ...p,
            enabled: ['kyc.view', 'kyc.doc_approve', 'kyc.doc_reject', 'kyc.make_valid_user'].includes(p.key)
          }))
        };
      }
      if (g.id === 'dashboard') {
        return { ...g, permissions: g.permissions.map(p => ({ ...p, enabled: true })) };
      }
      return g;
    })
  },
  {
    id: 'ROLE-005',
    name: 'Biker',
    description: 'Limited access for bike riders - can view dashboard, request KYC, manage rentals',
    isDefault: false,
    permissionGroups: buildDefaultGroups().map(g => {
      if (g.id === 'dashboard') {
        return { ...g, permissions: g.permissions.map(p => ({ ...p, enabled: true })) };
      }
      if (g.id === 'kyc') {
        return {
          ...g,
          permissions: g.permissions.map(p => ({
            ...p,
            enabled: ['kyc.request', 'kyc.view'].includes(p.key)
          }))
        };
      }
      if (g.id === 'rentals') {
        return {
          ...g,
          permissions: g.permissions.map(p => ({
            ...p,
            enabled: ['rentals.view', 'rentals.create'].includes(p.key)
          }))
        };
      }
      return g;
    })
  },
];

function Toggle({ checked, onChange, color = 'blue' }: { checked: boolean; onChange: () => void; color?: string }) {
  const colors: Record<string, string> = {
    blue: checked ? 'bg-blue-600' : 'bg-slate-200',
    green: checked ? 'bg-green-600' : 'bg-slate-200',
    amber: checked ? 'bg-amber-600' : 'bg-slate-200',
    red: checked ? 'bg-red-600' : 'bg-slate-200',
  };
  return (
    <button
      onClick={onChange}
      className={`relative inline-flex h-5 w-9 items-center rounded-full transition-colors ${colors[color] || colors.blue}`}
    >
      <span
        className={`inline-block h-4 w-4 transform rounded-full bg-white transition-transform ${checked ? 'translate-x-4' : 'translate-x-1'
          }`}
      />
    </button>
  );
}

export default function RolesPage() {
  const [roles, setRoles] = useState<Role[]>(mockRoles);
  const [search, setSearch] = useState('');
  const [showCreateModal, setShowCreateModal] = useState(false);
  const [editingRole, setEditingRole] = useState<Role | null>(null);
  const [selectedRole, setSelectedRole] = useState<Role | null>(null);
  const [expandedGroups, setExpandedGroups] = useState<Record<string, boolean>>({});
  const [formData, setFormData] = useState({ name: '', description: '' });

  const filteredRoles = roles.filter(r =>
    r.name.toLowerCase().includes(search.toLowerCase()) ||
    r.description.toLowerCase().includes(search.toLowerCase())
  );

  const handleSave = () => {
    if (!formData.name) return;
    if (editingRole) {
      setRoles(roles.map(r => r.id === editingRole.id ? { ...r, ...formData, isDefault: false } : r));
    } else {
      const newRole: Role = {
        id: `ROLE-${String(roles.length + 1).padStart(3, '0')}`,
        ...formData,
        isDefault: false,
        permissionGroups: buildDefaultGroups()
      };
      setRoles([...roles, newRole]);
    }
    setShowCreateModal(false);
    setEditingRole(null);
    setFormData({ name: '', description: '' });
  };

  const handleDelete = (id: string) => {
    if (confirm('Are you sure you want to delete this role?')) {
      setRoles(roles.filter(r => r.id !== id));
      setSelectedRole(null);
    }
  };

  const handleDuplicate = (role: Role) => {
    const newRole: Role = {
      id: `ROLE-${String(roles.length + 1).padStart(3, '0')}`,
      name: `${role.name} (Copy)`,
      description: role.description,
      isDefault: false,
      permissionGroups: role.permissionGroups.map(g => ({
        ...g,
        permissions: g.permissions.map(p => ({ ...p }))
      }))
    };
    setRoles([...roles, newRole]);
    setSelectedRole(newRole);
  };

  const openEdit = (role: Role) => {
    setEditingRole(role);
    setFormData({ name: role.name, description: role.description });
    setShowCreateModal(true);
  };

  const togglePermission = (groupIndex: number, permIndex: number) => {
    if (!selectedRole) return;
    const updated = [...selectedRole.permissionGroups];
    const perm = updated[groupIndex].permissions[permIndex];
    perm.enabled = !perm.enabled;
    setSelectedRole({ ...selectedRole, permissionGroups: updated });
    setRoles(roles.map(r => r.id === selectedRole.id ? { ...selectedRole, permissionGroups: updated } : r));
  };

  const toggleGroupAll = (groupIndex: number, enabled: boolean) => {
    if (!selectedRole) return;
    const updated = [...selectedRole.permissionGroups];
    updated[groupIndex].permissions = updated[groupIndex].permissions.map(p => ({ ...p, enabled }));
    setSelectedRole({ ...selectedRole, permissionGroups: updated });
    setRoles(roles.map(r => r.id === selectedRole.id ? { ...selectedRole, permissionGroups: updated } : r));
  };

  const isGroupAllEnabled = (group: PermissionGroup) => group.permissions.every(p => p.enabled);
  const getEnabledCount = (group: PermissionGroup) => group.permissions.filter(p => p.enabled).length;
  const getTotalEnabled = (role: Role) => role.permissionGroups.reduce((a, g) => a + g.permissions.filter(p => p.enabled).length, 0);

  const toggleGroup = (groupId: string) => {
    setExpandedGroups(prev => ({ ...prev, [groupId]: !prev[groupId] }));
  };

  return (
    <div className="p-4 lg:p-6">
      <div className="flex flex-col lg:flex-row lg:items-center lg:justify-between gap-4 mb-6">
        <div>
          <h1 className="text-2xl lg:text-3xl font-extrabold text-slate-800">Roles & Permissions</h1>
          <p className="text-sm text-slate-500 mt-1">Manage roles and access permissions</p>
        </div>
        <button
          onClick={() => {
            setEditingRole(null);
            setFormData({ name: '', description: '' });
            setShowCreateModal(true);
          }}
          className="py-2.5 px-4 bg-accent text-white rounded-lg font-semibold text-sm hover:bg-accent-dark transition-colors flex items-center gap-2"
        >
          <Plus className="w-4 h-4" /> Create Role
        </button>
      </div>

      <div className="grid grid-cols-2 lg:grid-cols-4 gap-4 mb-6">
        <div className="bg-white rounded-xl p-5 shadow-sm border border-slate-100">
          <p className="text-2xl font-extrabold text-slate-800">{roles.length}</p>
          <p className="text-sm text-slate-500">Total Roles</p>
        </div>
        <div className="bg-white rounded-xl p-5 shadow-sm border border-slate-100">
          <p className="text-2xl font-extrabold text-green-600">{roles.filter(r => r.isDefault).length}</p>
          <p className="text-sm text-slate-500">Default Roles</p>
        </div>
        <div className="bg-white rounded-xl p-5 shadow-sm border border-slate-100">
          <p className="text-2xl font-extrabold text-blue-600">{roles.reduce((a, r) => a + getTotalEnabled(r), 0)}</p>
          <p className="text-sm text-slate-500">Total Permissions</p>
        </div>
        <div className="bg-white rounded-xl p-5 shadow-sm border border-slate-100">
          <p className="text-2xl font-extrabold text-purple-600">{selectedRole ? getTotalEnabled(selectedRole) : '-'}</p>
          <p className="text-sm text-slate-500">Selected Role Perms</p>
        </div>
      </div>

      <div className="grid lg:grid-cols-3 gap-6">
        <div className="lg:col-span-1 bg-white rounded-xl shadow-sm border border-slate-100">
          <div className="p-4 border-b border-slate-100">
            <div className="relative">
              <Search className="absolute left-3 top-1/2 -translate-y-1/2 w-4 h-4 text-slate-400" />
              <input
                type="text"
                placeholder="Search roles..."
                value={search}
                onChange={(e) => setSearch(e.target.value)}
                className="w-full pl-10 pr-4 py-2 border border-slate-200 rounded-lg text-sm focus:outline-none focus:ring-2 focus:ring-accent focus:border-transparent"
              />
            </div>
          </div>
          <div className="divide-y divide-slate-50 max-h-[600px] overflow-y-auto">
            {filteredRoles.map(role => (
              <div
                key={role.id}
                className={`p-4 hover:bg-slate-50 cursor-pointer transition-colors ${selectedRole?.id === role.id ? 'bg-accent-light' : ''}`}
                onClick={() => setSelectedRole(role)}
              >
                <div className="flex items-center justify-between">
                  <div>
                    <p className="text-sm font-medium text-slate-700">{role.name}</p>
                    <p className="text-xs text-slate-400 truncate">{role.description}</p>
                  </div>
                  {role.isDefault && (
                    <span className="text-xs px-2 py-0.5 bg-accent-light text-accent rounded-full">Default</span>
                  )}
                </div>
                <div className="flex items-center gap-2 mt-2 text-xs text-slate-400">
                  <span>{getTotalEnabled(role)} permissions</span>
                </div>
              </div>
            ))}
          </div>
        </div>

        <div className="lg:col-span-2 bg-white rounded-xl shadow-sm border border-slate-100">
          {selectedRole ? (
            <>
              <div className="p-4 border-b border-slate-100 flex items-center justify-between">
                <div>
                  <h3 className="text-lg font-semibold text-slate-800">{selectedRole.name}</h3>
                  <p className="text-sm text-slate-500">{selectedRole.description}</p>
                </div>
                <div className="flex gap-2">
                  <button onClick={() => handleDuplicate(selectedRole)} className="p-2 hover:bg-slate-100 rounded-lg text-slate-600">
                    <Copy className="w-4 h-4" />
                  </button>
                  <button onClick={() => openEdit(selectedRole)} className="p-2 hover:bg-slate-100 rounded-lg text-slate-600">
                    <Edit className="w-4 h-4" />
                  </button>
                  {!selectedRole.isDefault && (
                    <button onClick={() => handleDelete(selectedRole.id)} className="p-2 hover:bg-red-50 rounded-lg text-red-500">
                      <Trash2 className="w-4 h-4" />
                    </button>
                  )}
                </div>
              </div>
              <div className="p-4 space-y-3 max-h-[600px] overflow-y-auto">
                {selectedRole.permissionGroups.map((group, gi) => (
                  <div key={group.id} className="border border-slate-200 rounded-lg">
                    <div
                      className="flex items-center justify-between p-3 cursor-pointer hover:bg-slate-50"
                      onClick={() => toggleGroup(group.id)}
                    >
                      <div className="flex items-center gap-3">
                        <group.icon className="w-5 h-5 text-slate-600" />
                        <div>
                          <p className="text-sm font-medium text-slate-700">{group.title}</p>
                          <p className="text-xs text-slate-400">{getEnabledCount(group)}/{group.permissions.length} enabled</p>
                        </div>
                      </div>
                      <div className="flex items-center gap-2">
                        <button
                          onClick={(e) => {
                            e.stopPropagation();
                            toggleGroupAll(gi, !isGroupAllEnabled(group));
                          }}
                          className="text-xs px-2 py-1 bg-slate-100 hover:bg-slate-200 rounded text-slate-600"
                        >
                          {isGroupAllEnabled(group) ? 'Uncheck All' : 'Check All'}
                        </button>
                        {expandedGroups[group.id] ? (
                          <ChevronDown className="w-4 h-4 text-slate-400" />
                        ) : (
                          <ChevronRight className="w-4 h-4 text-slate-400" />
                        )}
                      </div>
                    </div>
                    {expandedGroups[group.id] && (
                      <div className="border-t border-slate-200">
                        <div className="px-3 py-2 bg-slate-50">
                          <p className="text-xs text-slate-500">{group.description}</p>
                        </div>
                        <div className="divide-y divide-slate-100">
                          {group.permissions.map((perm, pi) => (
                            <div key={perm.key} className="flex items-center justify-between px-3 py-2.5">
                              <div className="flex items-center gap-2">
                                {perm.enabled ? (
                                  <Check className="w-4 h-4 text-green-600" />
                                ) : (
                                  <X className="w-4 h-4 text-slate-300" />
                                )}
                                <span className="text-sm text-slate-700">{perm.label}</span>
                                <span className="text-xs text-slate-400 font-mono">{perm.key}</span>
                              </div>
                              <Toggle
                                checked={perm.enabled}
                                onChange={() => togglePermission(gi, pi)}
                              />
                            </div>
                          ))}
                        </div>
                      </div>
                    )}
                  </div>
                ))}
              </div>
            </>
          ) : (
            <div className="p-12 text-center text-slate-500">
              <Shield className="w-12 h-12 mx-auto mb-4 text-slate-300" />
              <p className="text-sm">Select a role to view and edit permissions</p>
            </div>
          )}
        </div>
      </div>

      {showCreateModal && (
        <div className="fixed inset-0 bg-black/50 flex items-center justify-center z-50 p-4">
          <div className="bg-white rounded-xl shadow-xl w-full max-w-md">
            <div className="p-4 border-b border-slate-100 flex justify-between items-center">
              <h3 className="font-semibold text-slate-800">{editingRole ? 'Edit Role' : 'Create New Role'}</h3>
              <button onClick={() => setShowCreateModal(false)} className="text-slate-400 hover:text-slate-600">
                <X className="w-5 h-5" />
              </button>
            </div>
            <div className="p-4 space-y-4">
              <div>
                <label className="text-sm text-slate-600">Role Name *</label>
                <input
                  type="text"
                  value={formData.name}
                  onChange={(e) => setFormData({ ...formData, name: e.target.value })}
                  className="w-full px-3 py-2 border border-slate-200 rounded-lg text-sm mt-1"
                  placeholder="e.g., Super Manager"
                />
              </div>
              <div>
                <label className="text-sm text-slate-600">Description</label>
                <textarea
                  value={formData.description}
                  onChange={(e) => setFormData({ ...formData, description: e.target.value })}
                  className="w-full px-3 py-2 border border-slate-200 rounded-lg text-sm mt-1"
                  rows={2}
                  placeholder="Describe what this role can do"
                />
              </div>
            </div>
            <div className="p-4 border-t border-slate-100 flex justify-end gap-2">
              <button
                onClick={() => setShowCreateModal(false)}
                className="px-4 py-2 border border-slate-200 text-slate-600 rounded-lg text-sm"
              >
                Cancel
              </button>
              <button
                onClick={handleSave}
                disabled={!formData.name}
                className="px-4 py-2 bg-accent text-white rounded-lg text-sm disabled:opacity-50"
              >
                {editingRole ? 'Update' : 'Create'}
              </button>
            </div>
          </div>
        </div>
      )}
    </div>
  );
}