'use client'

import { useEffect, useMemo, useState } from 'react'
import { useRouter } from 'next/navigation'
import { authFetch, clearToken, getApiBase, getToken } from '../../lib/auth'
import AdminShell from '../../ui/AdminShell'

type RequestRow = {
  id: number
  title?: string | null
  year?: number | null
  type?: string | null
  statusLabel?: string | null
  requestedBy?: string | null
  createdAt?: string | null
}

const formatDateTime = (value?: string | null) => {
  if (!value) return 'Unknown'
  const date = new Date(value)
  if (Number.isNaN(date.valueOf())) return value
  return date.toLocaleString()
}

export default function AdminRequestsAllPage() {
  const router = useRouter()
  const [rows, setRows] = useState<RequestRow[]>([])
  const [total, setTotal] = useState(0)
  const [loading, setLoading] = useState(false)
  const [error, setError] = useState<string | null>(null)
  const [pageSize, setPageSize] = useState(50)
  const [page, setPage] = useState(1)

  const pageCount = useMemo(() => {
    if (!total || pageSize <= 0) return 1
    return Math.max(1, Math.ceil(total / pageSize))
  }, [total, pageSize])

  const load = async () => {
    if (!getToken()) {
      router.push('/login')
      return
    }
    setLoading(true)
    setError(null)
    try {
      const baseUrl = getApiBase()
      const skip = (page - 1) * pageSize
      const response = await authFetch(
        `${baseUrl}/admin/requests/all?take=${pageSize}&skip=${skip}`
      )
      if (!response.ok) {
        if (response.status === 401) {
          clearToken()
          router.push('/login')
          return
        }
        if (response.status === 403) {
          router.push('/')
          return
        }
        throw new Error(`Load failed: ${response.status}`)
      }
      const data = await response.json()
      setRows(Array.isArray(data?.results) ? data.results : [])
      setTotal(Number(data?.total ?? 0))
    } catch (err) {
      console.error(err)
      setError('Unable to load requests.')
    } finally {
      setLoading(false)
    }
  }

  useEffect(() => {
    void load()
  }, [page, pageSize])

  useEffect(() => {
    if (page > pageCount) {
      setPage(pageCount)
    }
  }, [pageCount, page])

  return (
    <AdminShell
      title="All requests"
      subtitle="Paginated view of every cached request."
      actions={
        <button type="button" onClick={() => router.push('/admin')}>
          Back to settings
        </button>
      }
    >
      <section className="admin-section">
        <div className="admin-toolbar">
          <div className="admin-toolbar-info">
            <span>{total.toLocaleString()} total</span>
          </div>
          <div className="admin-toolbar-actions">
            <label className="admin-select">
              <span>Per page</span>
              <select value={pageSize} onChange={(e) => setPageSize(Number(e.target.value))}>
                <option value={25}>25</option>
                <option value={50}>50</option>
                <option value={100}>100</option>
                <option value={200}>200</option>
              </select>
            </label>
          </div>
        </div>
        {loading ? (
          <div className="status-banner">Loading requests…</div>
        ) : error ? (
          <div className="error-banner">{error}</div>
        ) : rows.length === 0 ? (
          <div className="status-banner">No requests found.</div>
        ) : (
          <div className="admin-table">
            <div className="admin-table-head">
              <span>Request</span>
              <span>Status</span>
              <span>Requested by</span>
              <span>Created</span>
            </div>
            {rows.map((row) => (
              <button
                key={row.id}
                type="button"
                className="admin-table-row"
                onClick={() => router.push(`/requests/${row.id}`)}
              >
                <span>
                  {row.title || `Request #${row.id}`}
                  {row.year ? ` (${row.year})` : ''}
                </span>
                <span>{row.statusLabel || 'Unknown'}</span>
                <span>{row.requestedBy || 'Unknown'}</span>
                <span>{formatDateTime(row.createdAt)}</span>
              </button>
            ))}
          </div>
        )}
        <div className="admin-pagination">
          <button type="button" onClick={() => setPage(1)} disabled={page <= 1}>
            First
          </button>
          <button type="button" onClick={() => setPage(page - 1)} disabled={page <= 1}>
            Previous
          </button>
          <span>
            Page {page} of {pageCount}
          </span>
          <button
            type="button"
            onClick={() => setPage(page + 1)}
            disabled={page >= pageCount}
          >
            Next
          </button>
          <button
            type="button"
            onClick={() => setPage(pageCount)}
            disabled={page >= pageCount}
          >
            Last
          </button>
        </div>
      </section>
    </AdminShell>
  )
}