'use client'

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

type AdminUser = {
  id: number
  username: string
  role: string
  authProvider?: string | null
  lastLoginAt?: string | null
  isBlocked?: boolean
  stats?: UserStats
}

type UserStats = {
  total: number
  ready: number
  pending: number
  approved: number
  working: number
  partial: number
  declined: number
  in_progress: number
  last_request_at?: string | null
}

const formatLastLogin = (value?: string | null) => {
  if (!value) return 'Never'
  const date = new Date(value)
  if (Number.isNaN(date.valueOf())) return value
  return date.toLocaleString()
}

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

const emptyStats: UserStats = {
  total: 0,
  ready: 0,
  pending: 0,
  approved: 0,
  working: 0,
  partial: 0,
  declined: 0,
  in_progress: 0,
  last_request_at: null,
}

const normalizeStats = (stats: any): UserStats => ({
  total: Number(stats?.total ?? 0),
  ready: Number(stats?.ready ?? 0),
  pending: Number(stats?.pending ?? 0),
  approved: Number(stats?.approved ?? 0),
  working: Number(stats?.working ?? 0),
  partial: Number(stats?.partial ?? 0),
  declined: Number(stats?.declined ?? 0),
  in_progress: Number(stats?.in_progress ?? 0),
  last_request_at: stats?.last_request_at ?? null,
})

export default function UsersPage() {
  const router = useRouter()
  const [users, setUsers] = useState<AdminUser[]>([])
  const [error, setError] = useState<string | null>(null)
  const [loading, setLoading] = useState(true)
  const [jellyseerrSyncStatus, setJellyseerrSyncStatus] = useState<string | null>(null)
  const [jellyseerrSyncBusy, setJellyseerrSyncBusy] = useState(false)
  const [jellyseerrResyncBusy, setJellyseerrResyncBusy] = useState(false)

  const loadUsers = async () => {
    try {
      const baseUrl = getApiBase()
      const response = await authFetch(`${baseUrl}/admin/users/summary`)
      if (!response.ok) {
        if (response.status === 401) {
          clearToken()
          router.push('/login')
          return
        }
        if (response.status === 403) {
          router.push('/')
          return
        }
        throw new Error('Could not load users.')
      }
      const data = await response.json()
      if (Array.isArray(data?.users)) {
        setUsers(
          data.users.map((user: any) => ({
            username: user.username ?? 'Unknown',
            role: user.role ?? 'user',
            authProvider: user.auth_provider ?? 'local',
            lastLoginAt: user.last_login_at ?? null,
            isBlocked: Boolean(user.is_blocked),
            id: Number(user.id ?? 0),
            stats: normalizeStats(user.stats ?? emptyStats),
          }))
        )
      } else {
        setUsers([])
      }
      setError(null)
    } catch (err) {
      console.error(err)
      setError('Could not load user list.')
    } finally {
      setLoading(false)
    }
  }

  const toggleUserBlock = async (username: string, blocked: boolean) => {
    try {
      const baseUrl = getApiBase()
      const response = await authFetch(
        `${baseUrl}/admin/users/${encodeURIComponent(username)}/${blocked ? 'block' : 'unblock'}`,
        { method: 'POST' }
      )
      if (!response.ok) {
        throw new Error('Update failed')
      }
      await loadUsers()
    } catch (err) {
      console.error(err)
      setError('Could not update user access.')
    }
  }

  const updateUserRole = async (username: string, role: string) => {
    try {
      const baseUrl = getApiBase()
      const response = await authFetch(
        `${baseUrl}/admin/users/${encodeURIComponent(username)}/role`,
        {
          method: 'POST',
          headers: { 'Content-Type': 'application/json' },
          body: JSON.stringify({ role }),
        }
      )
      if (!response.ok) {
        throw new Error('Update failed')
      }
      await loadUsers()
    } catch (err) {
      console.error(err)
      setError('Could not update user role.')
    }
  }

  const syncJellyseerrUsers = async () => {
    setJellyseerrSyncStatus(null)
    setJellyseerrSyncBusy(true)
    try {
      const baseUrl = getApiBase()
      const response = await authFetch(`${baseUrl}/admin/jellyseerr/users/sync`, {
        method: 'POST',
      })
      if (!response.ok) {
        const text = await response.text()
        throw new Error(text || 'Sync failed')
      }
      const data = await response.json()
      setJellyseerrSyncStatus(
        `Matched ${data?.matched ?? 0} users. Skipped ${data?.skipped ?? 0}.`
      )
      await loadUsers()
    } catch (err) {
      console.error(err)
      setJellyseerrSyncStatus('Could not sync Jellyseerr users.')
    } finally {
      setJellyseerrSyncBusy(false)
    }
  }

  const resyncJellyseerrUsers = async () => {
    const confirmed = window.confirm(
      'This will remove all non-admin users and re-import from Jellyseerr. Continue?'
    )
    if (!confirmed) return
    setJellyseerrSyncStatus(null)
    setJellyseerrResyncBusy(true)
    try {
      const baseUrl = getApiBase()
      const response = await authFetch(`${baseUrl}/admin/jellyseerr/users/resync`, {
        method: 'POST',
      })
      if (!response.ok) {
        const text = await response.text()
        throw new Error(text || 'Resync failed')
      }
      const data = await response.json()
      setJellyseerrSyncStatus(
        `Re-imported ${data?.imported ?? 0} users. Cleared ${data?.cleared ?? 0}.`
      )
      await loadUsers()
    } catch (err) {
      console.error(err)
      setJellyseerrSyncStatus('Could not resync Jellyseerr users.')
    } finally {
      setJellyseerrResyncBusy(false)
    }
  }

  useEffect(() => {
    if (!getToken()) {
      router.push('/login')
      return
    }
    void loadUsers()
  }, [router])

  if (loading) {
    return <main className="card">Loading users...</main>
  }

  return (
    <AdminShell
      title="Users"
      subtitle="Manage who can use Magent."
      actions={
        <>
          <button type="button" onClick={loadUsers}>
            Reload list
          </button>
          <button type="button" onClick={syncJellyseerrUsers} disabled={jellyseerrSyncBusy}>
            {jellyseerrSyncBusy ? 'Syncing Jellyseerr users...' : 'Sync Jellyseerr users'}
          </button>
          <button type="button" onClick={resyncJellyseerrUsers} disabled={jellyseerrResyncBusy}>
            {jellyseerrResyncBusy ? 'Resyncing Jellyseerr users...' : 'Resync Jellyseerr users'}
          </button>
        </>
      }
    >
      <section className="admin-section">
        {error && <div className="error-banner">{error}</div>}
        {jellyseerrSyncStatus && <div className="status-banner">{jellyseerrSyncStatus}</div>}
        {users.length === 0 ? (
          <div className="status-banner">No users found yet.</div>
        ) : (
          <div className="user-grid">
            {users.map((user) => (
              <Link
                key={user.username}
                className="user-grid-card"
                href={`/users/${user.id}`}
              >
                <div className="user-grid-header">
                  <div>
                    <strong>{user.username}</strong>
                    <span className="user-grid-meta">{user.role}</span>
                  </div>
                  <span className={`user-grid-pill ${user.isBlocked ? 'is-blocked' : ''}`}>
                    {user.isBlocked ? 'Blocked' : 'Active'}
                  </span>
                </div>
                <div className="user-grid-stats">
                  <div>
                    <span className="label">Total</span>
                    <span className="value">{user.stats?.total ?? 0}</span>
                  </div>
                  <div>
                    <span className="label">Ready</span>
                    <span className="value">{user.stats?.ready ?? 0}</span>
                  </div>
                  <div>
                    <span className="label">Pending</span>
                    <span className="value">{user.stats?.pending ?? 0}</span>
                  </div>
                  <div>
                    <span className="label">In progress</span>
                    <span className="value">{user.stats?.in_progress ?? 0}</span>
                  </div>
                </div>
                <div className="user-grid-footer">
                  <span className="meta">Login: {user.authProvider || 'local'}</span>
                  <span className="meta">Last login: {formatLastLogin(user.lastLoginAt)}</span>
                  <span className="meta">
                    Last request: {formatLastRequest(user.stats?.last_request_at)}
                  </span>
                </div>
              </Link>
            ))}
          </div>
        )}
      </section>
    </AdminShell>
  )
}