import { useEffect, useState } from 'react'
import { Card } from '@/components/ui/Card'
import { Skeleton } from '@/components/ui/Skeleton'
import {
  Table,
  TableHead,
  TableBody,
  TableRow,
  TableHeader,
  TableCell,
} from '@/components/ui/Table'
import { Badge } from '@/components/ui/Badge'
import { Button } from '@/components/ui/Button'
import { formatDate } from '@/lib/utils'
import { hrApi } from '@/lib/api'
import {
  Users,
  Calendar,
  Plus,
  Search,
  Filter,
  MoreHorizontal,
  Clock,
} from 'lucide-react'
import { AgentFAB } from '@/components/agent/AgentFAB'

interface Employee {
  id: string
  first_name: string
  last_name: string
  name?: string
  email: string
  department: string
  position: string
  role?: string
  status: string
  start_date?: string
  startDate?: string
}

interface Leave {
  id: string
  employeeId: string
  employeeName: string
  type: string
  startDate: string
  endDate: string
  status: string
  days: number
}

const tabs = ['Employees', 'Leaves']

const departmentColors: Record<string, string> = {
  Sales: 'primary',
  Engineering: 'success',
  Finance: 'warning',
  HR: 'primary',
  Legal: 'default',
}

export function HRPage() {
  const [activeTab, setActiveTab] = useState('Employees')
  const [searchQuery, setSearchQuery] = useState('')
  const [loading, setLoading] = useState(true)
  const [error, setError] = useState('')

  const [employees, setEmployees] = useState<Employee[]>([])
  const [leaves, setLeaves] = useState<Leave[]>([])

  useEffect(() => {
    async function fetchData() {
      setLoading(true)
      setError('')
      try {
        const [employeesRes, leavesRes] = await Promise.all([
          hrApi.employees(),
          hrApi.leaves(),
        ])
        setEmployees((employeesRes as { employees: Employee[] }).employees || [])
        setLeaves((leavesRes as { leaves: Leave[] }).leaves || [])
      } catch (err) {
        setError(err instanceof Error ? err.message : 'Failed to load HR data')
      } finally {
        setLoading(false)
      }
    }

    fetchData()
  }, [])

  const activeEmployees = employees.filter((e) => e.status === 'active').length
  const onLeave = employees.filter((e) => e.status === 'on_leave').length
  const pendingLeaves = leaves.filter((l) => l.status === 'pending').length

  const filteredEmployees = employees.filter(
    (e) =>
      (e.name || `${e.first_name} ${e.last_name}`).toLowerCase().includes(searchQuery.toLowerCase()) ||
      e.department.toLowerCase().includes(searchQuery.toLowerCase()) ||
      (e.role || e.position).toLowerCase().includes(searchQuery.toLowerCase())
  )

  const filteredLeaves = leaves.filter(
    (l) =>
      l.employeeName.toLowerCase().includes(searchQuery.toLowerCase()) ||
      l.type.toLowerCase().includes(searchQuery.toLowerCase())
  )

  if (loading) {
    return (
      <div className="space-y-8">
        <div className="grid grid-cols-1 sm:grid-cols-3 gap-5">
          <Skeleton className="h-[80px]" />
          <Skeleton className="h-[80px]" />
          <Skeleton className="h-[80px]" />
        </div>
        <Skeleton className="h-[400px]" />
      </div>
    )
  }

  if (error) {
    return (
      <div className="flex items-center justify-center h-64">
        <p className="text-danger">{error}</p>
      </div>
    )
  }

  return (
    <div className="space-y-8">
      {/* Page Header */}
      <div className="flex flex-col sm:flex-row sm:items-center justify-between gap-4">
        <div>
          <h1 className="text-xl font-semibold text-text-primary">HR</h1>
          <p className="text-sm text-text-secondary mt-0.5">Employees and leave management</p>
        </div>
        <Button icon={<Plus size={16} />}>Add Employee</Button>
      </div>

      {/* Quick Stats */}
      <div className="grid grid-cols-1 sm:grid-cols-3 gap-5">
        <Card padding="md">
          <div className="flex items-center gap-3">
            <div className="w-10 h-10 rounded-xl bg-primary-light flex items-center justify-center text-primary">
              <Users size={18} />
            </div>
            <div>
              <p className="text-2xl font-semibold text-text-primary">{activeEmployees}</p>
              <p className="text-xs text-text-secondary">Active Employees</p>
            </div>
          </div>
        </Card>
        <Card padding="md">
          <div className="flex items-center gap-3">
            <div className="w-10 h-10 rounded-xl bg-warning-light flex items-center justify-center text-warning">
              <Clock size={18} />
            </div>
            <div>
              <p className="text-2xl font-semibold text-text-primary">{onLeave}</p>
              <p className="text-xs text-text-secondary">On Leave</p>
            </div>
          </div>
        </Card>
        <Card padding="md">
          <div className="flex items-center gap-3">
            <div className="w-10 h-10 rounded-xl bg-success-light flex items-center justify-center text-success">
              <Calendar size={18} />
            </div>
            <div>
              <p className="text-2xl font-semibold text-text-primary">{pendingLeaves}</p>
              <p className="text-xs text-text-secondary">Pending Requests</p>
            </div>
          </div>
        </Card>
      </div>

      {/* Tabs + Search */}
      <div className="flex flex-col sm:flex-row items-start sm:items-center justify-between gap-4">
        <div className="flex items-center gap-1 bg-bg rounded-xl p-1">
          {tabs.map((tab) => (
            <button
              key={tab}
              onClick={() => setActiveTab(tab)}
              className={`px-4 py-2 text-sm font-medium rounded-lg transition-colors ${
                activeTab === tab
                  ? 'bg-surface text-text-primary shadow-sm'
                  : 'text-text-secondary hover:text-text-primary'
              }`}
            >
              {tab}
            </button>
          ))}
        </div>
        <div className="flex items-center gap-2 w-full sm:w-auto">
          <div className="relative flex-1 sm:flex-initial">
            <Search size={15} className="absolute left-3 top-1/2 -translate-y-1/2 text-text-secondary" />
            <input
              type="text"
              placeholder="Search..."
              value={searchQuery}
              onChange={(e) => setSearchQuery(e.target.value)}
              className="w-full sm:w-64 h-10 pl-9 pr-4 rounded-[14px] border bg-surface text-sm text-text-primary placeholder:text-text-secondary/50 focus:outline-none focus:ring-2 focus:ring-primary/20 focus:border-primary/30"
            />
          </div>
          <Button variant="secondary" size="sm" icon={<Filter size={14} />}>
            Filter
          </Button>
        </div>
      </div>

      {/* Tab Content */}
      {activeTab === 'Employees' && (
        <Card>
          <Table>
            <TableHead>
              <TableRow>
                <TableHeader>Employee</TableHeader>
                <TableHeader>Department</TableHeader>
                <TableHeader>Role</TableHeader>
                <TableHeader>Status</TableHeader>
                <TableHeader>Start Date</TableHeader>
                <TableHeader align="right"></TableHeader>
              </TableRow>
            </TableHead>
            <TableBody>
              {filteredEmployees.map((employee) => {
                const empName = employee.name || `${employee.first_name} ${employee.last_name}`
                const empRole = employee.role || employee.position
                const empStartDate = employee.startDate || employee.start_date
                return (
                <TableRow key={employee.id}>
                  <TableCell>
                    <div className="flex items-center gap-3">
                      <div className="w-8 h-8 rounded-lg bg-primary/10 text-primary flex items-center justify-center text-xs font-semibold">
                        {empName.split(' ').map((n) => n[0]).join('')}
                      </div>
                      <div>
                        <p className="font-medium text-text-primary">{empName}</p>
                        <p className="text-xs text-text-secondary">{employee.email}</p>
                      </div>
                    </div>
                  </TableCell>
                  <TableCell>
                    <Badge variant={(departmentColors[employee.department] as 'primary' | 'success' | 'warning' | 'default') || 'default'}>
                      {employee.department}
                    </Badge>
                  </TableCell>
                  <TableCell>{empRole}</TableCell>
                  <TableCell>
                    <Badge
                      variant={
                        employee.status === 'active'
                          ? 'success'
                          : employee.status === 'on_leave'
                          ? 'warning'
                          : 'danger'
                      }
                    >
                      {employee.status.replace('_', ' ')}
                    </Badge>
                  </TableCell>
                  <TableCell>{formatDate(empStartDate || '')}</TableCell>
                  <TableCell align="right">
                    <button className="w-8 h-8 flex items-center justify-center rounded-lg hover:bg-bg text-text-secondary">
                      <MoreHorizontal size={16} />
                    </button>
                  </TableCell>
                </TableRow>
              )})}
              {filteredEmployees.length === 0 && (
                <TableRow>
                  <TableCell colSpan={6} className="text-center text-text-secondary py-8">
                    No employees found
                  </TableCell>
                </TableRow>
              )}
            </TableBody>
          </Table>
        </Card>
      )}

      {activeTab === 'Leaves' && (
        <Card>
          <Table>
            <TableHead>
              <TableRow>
                <TableHeader>Employee</TableHeader>
                <TableHeader>Type</TableHeader>
                <TableHeader>Period</TableHeader>
                <TableHeader align="right">Days</TableHeader>
                <TableHeader>Status</TableHeader>
                <TableHeader align="right"></TableHeader>
              </TableRow>
            </TableHead>
            <TableBody>
              {filteredLeaves.map((leave) => (
                <TableRow key={leave.id}>
                  <TableCell>
                    <div className="flex items-center gap-3">
                      <div className="w-8 h-8 rounded-lg bg-primary/10 text-primary flex items-center justify-center text-xs font-semibold">
                        {leave.employeeName.split(' ').map((n) => n[0]).join('')}
                      </div>
                      <span className="font-medium text-text-primary">{leave.employeeName}</span>
                    </div>
                  </TableCell>
                  <TableCell>
                    <Badge variant={leave.type === 'vacation' ? 'primary' : leave.type === 'sick' ? 'warning' : 'default'}>
                      {leave.type}
                    </Badge>
                  </TableCell>
                  <TableCell>
                    <span className="text-sm text-text-primary">
                      {formatDate(leave.startDate)} — {formatDate(leave.endDate)}
                    </span>
                  </TableCell>
                  <TableCell align="right">
                    <span className="font-medium">{leave.days}</span>
                  </TableCell>
                  <TableCell>
                    <Badge
                      variant={
                        leave.status === 'approved'
                          ? 'success'
                          : leave.status === 'pending'
                          ? 'warning'
                          : 'danger'
                      }
                    >
                      {leave.status}
                    </Badge>
                  </TableCell>
                  <TableCell align="right">
                    <button className="w-8 h-8 flex items-center justify-center rounded-lg hover:bg-bg text-text-secondary">
                      <MoreHorizontal size={16} />
                    </button>
                  </TableCell>
                </TableRow>
              ))}
              {filteredLeaves.length === 0 && (
                <TableRow>
                  <TableCell colSpan={6} className="text-center text-text-secondary py-8">
                    No leave requests found
                  </TableCell>
                </TableRow>
              )}
            </TableBody>
          </Table>
        </Card>
      )}

      {/* HR Agent */}
      <AgentFAB rum="hr" />
    </div>
  )
}