import { useEffect, useState } from 'react'
import { ShieldCheck, UserPlus, Trash2, Loader2, Crown, Mail } from 'lucide-react'
import { useApp } from '../lib/AppContext'
import { useFeedback } from '../lib/feedback'
import { MemberRole, ROLE_LABELS } from '../lib/types'
import {
  AdminUser,
  adminListUsers,
  adminCreateUser,
  adminDeleteUser,
  adminUpdateUser
} from '../lib/admin'
import { Modal, Select, EmptyState } from '../components/ui'
import PageHeader from '../components/PageHeader'

export default function Admin(): JSX.Element {
  const { profile } = useApp()
  const { toast, confirm } = useFeedback()
  const [users, setUsers] = useState<AdminUser[]>([])
  const [loading, setLoading] = useState(true)
  const [error, setError] = useState('')
  const [creating, setCreating] = useState(false)

  const load = async (): Promise<void> => {
    setLoading(true)
    setError('')
    try {
      setUsers(await adminListUsers())
    } catch (e) {
      setError((e as Error).message)
    } finally {
      setLoading(false)
    }
  }
  useEffect(() => {
    load()
  }, [])

  const setRole = async (u: AdminUser, role: MemberRole): Promise<void> => {
    setUsers((list) => list.map((x) => (x.id === u.id ? { ...x, role } : x)))
    try {
      await adminUpdateUser(u.id, { role })
    } catch (e) {
      setError((e as Error).message)
      load()
    }
  }

  const toggleAdmin = async (u: AdminUser): Promise<void> => {
    try {
      await adminUpdateUser(u.id, { is_admin: !u.is_admin })
      setUsers((list) => list.map((x) => (x.id === u.id ? { ...x, is_admin: !u.is_admin } : x)))
    } catch (e) {
      setError((e as Error).message)
    }
  }

  const remove = async (u: AdminUser): Promise<void> => {
    const ok = await confirm({
      title: 'Supprimer ce compte ?',
      message: `${u.full_name} (${u.email}) sera définitivement supprimé.`,
      danger: true,
      confirmLabel: 'Supprimer'
    })
    if (!ok) return
    try {
      await adminDeleteUser(u.id)
      setUsers((list) => list.filter((x) => x.id !== u.id))
      toast('Compte supprimé.', 'success')
    } catch (e) {
      setError((e as Error).message)
    }
  }

  return (
    <div className="flex h-full flex-col">
      <PageHeader title="Administration" subtitle={`${users.length} compte(s)`}>
        <button className="btn-primary" onClick={() => setCreating(true)}>
          <UserPlus size={16} /> Créer un compte
        </button>
      </PageHeader>

      <div className="flex-1 overflow-y-auto p-6">
        {error && (
          <div className="mb-4 rounded-lg border border-rose-500/30 bg-rose-500/10 px-3 py-2 text-sm text-rose-600">
            {error}
          </div>
        )}

        {loading ? (
          <div className="flex justify-center py-16 text-muted">
            <Loader2 className="animate-spin" size={28} />
          </div>
        ) : users.length === 0 ? (
          <EmptyState icon={<ShieldCheck size={40} />} text="Aucun compte." />
        ) : (
          <div className="overflow-hidden rounded-xl border border-border">
            <table className="w-full text-sm">
              <thead className="bg-panel2 text-left text-xs uppercase text-subtle">
                <tr>
                  <th className="px-4 py-3">Membre</th>
                  <th className="px-4 py-3">Rôle</th>
                  <th className="px-4 py-3">Admin</th>
                  <th className="px-4 py-3 text-right">Actions</th>
                </tr>
              </thead>
              <tbody>
                {users.map((u) => {
                  const isMe = u.id === profile?.id
                  return (
                    <tr key={u.id} className="border-t border-border">
                      <td className="px-4 py-3">
                        <div className="font-medium text-ink">
                          {u.full_name}
                          {isMe && <span className="ml-1 text-xs text-accent2">(moi)</span>}
                        </div>
                        <div className="flex items-center gap-1 text-xs text-subtle">
                          <Mail size={11} /> {u.email}
                        </div>
                      </td>
                      <td className="px-4 py-3">
                        <Select
                          className="!py-1 text-xs"
                          value={u.role}
                          onChange={(e) => setRole(u, e.target.value as MemberRole)}
                        >
                          {Object.entries(ROLE_LABELS).map(([v, l]) => (
                            <option key={v} value={v}>
                              {l}
                            </option>
                          ))}
                        </Select>
                      </td>
                      <td className="px-4 py-3">
                        <button
                          onClick={() => toggleAdmin(u)}
                          disabled={isMe}
                          title={isMe ? 'Tu ne peux pas retirer ton propre statut' : 'Basculer admin'}
                          className={`inline-flex items-center gap-1 rounded-full px-2 py-1 text-xs ${
                            u.is_admin
                              ? 'bg-amber-100 text-amber-700'
                              : 'bg-panel2 text-muted hover:text-ink'
                          } ${isMe ? 'cursor-not-allowed opacity-60' : ''}`}
                        >
                          <Crown size={12} /> {u.is_admin ? 'Admin' : 'Membre'}
                        </button>
                      </td>
                      <td className="px-4 py-3 text-right">
                        <button
                          onClick={() => remove(u)}
                          disabled={isMe}
                          title={isMe ? 'Impossible de supprimer son propre compte' : 'Supprimer'}
                          className={`text-muted hover:text-rose-600 ${
                            isMe ? 'cursor-not-allowed opacity-40' : ''
                          }`}
                        >
                          <Trash2 size={16} />
                        </button>
                      </td>
                    </tr>
                  )
                })}
              </tbody>
            </table>
          </div>
        )}
      </div>

      {creating && (
        <CreateUserModal
          onClose={() => setCreating(false)}
          onCreated={async () => {
            setCreating(false)
            await load()
            toast('Compte créé.', 'success')
          }}
        />
      )}
    </div>
  )
}

function CreateUserModal({
  onClose,
  onCreated
}: {
  onClose: () => void
  onCreated: () => Promise<void>
}): JSX.Element {
  const [email, setEmail] = useState('')
  const [password, setPassword] = useState('')
  const [fullName, setFullName] = useState('')
  const [role, setRole] = useState<MemberRole>('programmer')
  const [isAdmin, setIsAdmin] = useState(false)
  const [busy, setBusy] = useState(false)
  const [error, setError] = useState('')

  const submit = async (): Promise<void> => {
    setError('')
    if (!email.trim() || password.length < 6) {
      setError('Email valide et mot de passe (6+ caractères) requis.')
      return
    }
    setBusy(true)
    try {
      await adminCreateUser({
        email: email.trim(),
        password,
        full_name: fullName.trim(),
        role,
        is_admin: isAdmin
      })
      await onCreated()
    } catch (e) {
      setError((e as Error).message)
      setBusy(false)
    }
  }

  return (
    <Modal title="Créer un compte" onClose={onClose}>
      <label className="label">Nom complet</label>
      <input
        className="input mb-3"
        placeholder="Alex Martin"
        value={fullName}
        onChange={(e) => setFullName(e.target.value)}
      />
      <label className="label">Email</label>
      <input
        className="input mb-3"
        type="email"
        placeholder="alex@email.com"
        value={email}
        onChange={(e) => setEmail(e.target.value)}
      />
      <label className="label">Mot de passe provisoire</label>
      <input
        className="input mb-3"
        type="text"
        placeholder="au moins 6 caractères"
        value={password}
        onChange={(e) => setPassword(e.target.value)}
      />
      <label className="label">Rôle</label>
      <Select className="mb-3" value={role} onChange={(e) => setRole(e.target.value as MemberRole)}>
        {Object.entries(ROLE_LABELS).map(([v, l]) => (
          <option key={v} value={v}>
            {l}
          </option>
        ))}
      </Select>
      <label className="mb-4 flex cursor-pointer items-center gap-2 text-sm text-gray-600">
        <input
          type="checkbox"
          checked={isAdmin}
          onChange={(e) => setIsAdmin(e.target.checked)}
          className="h-4 w-4 accent-accent"
        />
        Donner les droits administrateur
      </label>

      {error && <p className="mb-3 text-sm text-rose-600">{error}</p>}

      <button className="btn-primary w-full" onClick={submit} disabled={busy}>
        {busy && <Loader2 className="animate-spin" size={16} />}
        Créer le compte
      </button>
      <p className="mt-3 text-center text-xs text-subtle">
        Communique l'email et le mot de passe provisoire au membre.
      </p>
    </Modal>
  )
}