'use client'

import { useEffect, useState } from 'react'
import { RefreshCw, Plus, Trash2, KeyRound } from 'lucide-react'

import { api } from '@/config/api'
import { useAuth } from '@/hooks/useAuth'
import { ensureErrorMessage } from '@/helpers/ensureErrorMessage'
import { Button } from '@/components/ui/button'
import { Input } from '@/components/ui/input'
import { Label } from '@/components/ui/label'
import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card'
import { Alert, AlertDescription } from '@/components/ui/alert'
import { Skeleton } from '@/components/ui/skeleton'
import {
  AlertDialog,
  AlertDialogAction,
  AlertDialogCancel,
  AlertDialogContent,
  AlertDialogDescription,
  AlertDialogFooter,
  AlertDialogHeader,
  AlertDialogTitle,
  AlertDialogTrigger,
} from '@/components/ui/alert-dialog'

type UserRecord = {
  id: string
  username: string
  displayName: string
  createdAt: string
}

export const UsersPage = () => {
  const { user: currentUser } = useAuth()
  const [users, setUsers] = useState<UserRecord[]>([])
  const [loading, setLoading] = useState(false)
  const [error, setError] = useState<string | null>(null)
  const [success, setSuccess] = useState<string | null>(null)

  // Form state
  const [formUsername, setFormUsername] = useState('')
  const [formPassword, setFormPassword] = useState('')
  const [formDisplayName, setFormDisplayName] = useState('')

  // Change password state
  const [changingPasswordId, setChangingPasswordId] = useState<string | null>(null)
  const [newPassword, setNewPassword] = useState('')

  const canSubmit = formUsername.trim().length >= 3 && formPassword.length >= 8 && formDisplayName.trim().length > 0

  const load = async () => {
    setLoading(true)
    setError(null)

    try {
      const res = await api.get<UserRecord[]>('/admin/users')
      setUsers(res.data)
    } catch (err) {
      setError(ensureErrorMessage(err))
    } finally {
      setLoading(false)
    }
  }

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

  const onCreate = async () => {
    if (!canSubmit) return

    setLoading(true)
    setError(null)
    setSuccess(null)

    try {
      await api.post('/admin/users', {
        username: formUsername.trim(),
        password: formPassword,
        displayName: formDisplayName.trim()
      })
      setFormUsername('')
      setFormPassword('')
      setFormDisplayName('')
      setSuccess('Utilisateur créé')
      await load()
    } catch (err) {
      const msg = ensureErrorMessage(err)
      if (msg.includes('username_taken')) {
        setError('Ce nom d\'utilisateur est déjà pris.')
      } else {
        setError(msg)
      }
    } finally {
      setLoading(false)
    }
  }

  const onChangePassword = async (id: string) => {
    if (newPassword.length < 8) return

    setLoading(true)
    setError(null)
    setSuccess(null)

    try {
      await api.patch(`/admin/users/${id}/password`, { password: newPassword })
      setChangingPasswordId(null)
      setNewPassword('')
      setSuccess('Mot de passe modifié')
    } catch (err) {
      setError(ensureErrorMessage(err))
    } finally {
      setLoading(false)
    }
  }

  const onDelete = async (id: string) => {
    setLoading(true)
    setError(null)
    setSuccess(null)

    try {
      await api.delete(`/admin/users/${id}`)
      setSuccess('Utilisateur supprimé')
      await load()
    } catch (err) {
      const msg = ensureErrorMessage(err)
      if (msg.includes('cannot_delete_self')) {
        setError('Vous ne pouvez pas supprimer votre propre compte.')
      } else {
        setError(msg)
      }
    } finally {
      setLoading(false)
    }
  }

  return (
    <div className="grid gap-4 max-w-[900px]">
      <div className="flex items-center justify-between gap-3">
        <div>
          <h1 className="text-2xl font-bold tracking-tight">Utilisateurs</h1>
          <p className="text-sm text-muted-foreground mt-1">
            Gérer les comptes utilisateurs
          </p>
        </div>
        <Button variant="outline" size="sm" onClick={() => void load()} disabled={loading}>
          <RefreshCw className={`h-4 w-4 mr-1 ${loading ? 'animate-spin' : ''}`} />
          Rafraîchir
        </Button>
      </div>

      {error ? (
        <Alert variant="destructive">
          <AlertDescription>{error}</AlertDescription>
        </Alert>
      ) : null}

      {success ? (
        <Alert>
          <AlertDescription>{success}</AlertDescription>
        </Alert>
      ) : null}

      {/* Formulaire d'ajout */}
      <Card>
        <CardHeader>
          <CardTitle className="text-base">Créer un utilisateur</CardTitle>
        </CardHeader>
        <CardContent className="grid gap-3">
          <div className="grid grid-cols-1 sm:grid-cols-3 gap-3">
            <div className="grid gap-1.5">
              <Label htmlFor="username">Nom d&apos;utilisateur</Label>
              <Input
                id="username"
                value={formUsername}
                onChange={(e) => setFormUsername(e.target.value)}
                placeholder="min. 3 caractères"
                autoCapitalize="none"
                autoCorrect="off"
                className="h-12"
              />
            </div>

            <div className="grid gap-1.5">
              <Label htmlFor="displayName">Nom d&apos;affichage</Label>
              <Input
                id="displayName"
                value={formDisplayName}
                onChange={(e) => setFormDisplayName(e.target.value)}
                placeholder="Prénom ou surnom"
                className="h-12"
              />
            </div>

            <div className="grid gap-1.5">
              <Label htmlFor="password">Mot de passe</Label>
              <Input
                id="password"
                type="password"
                value={formPassword}
                onChange={(e) => setFormPassword(e.target.value)}
                placeholder="min. 8 caractères"
                className="h-12"
              />
            </div>
          </div>

          <Button
            onClick={() => void onCreate()}
            disabled={!canSubmit || loading}
            className="h-12 w-full sm:w-auto"
          >
            <Plus className="h-4 w-4 mr-1" />
            Créer
          </Button>
        </CardContent>
      </Card>

      {/* Liste des utilisateurs */}
      {loading && users.length === 0 ? (
        <div className="grid gap-3">
          <Skeleton className="h-20 rounded-lg" />
          <Skeleton className="h-20 rounded-lg" />
        </div>
      ) : (
        <Card>
          <CardHeader>
            <CardTitle className="text-base">
              Comptes ({users.length})
            </CardTitle>
          </CardHeader>
          <CardContent>
            {users.length === 0 ? (
              <p className="text-sm text-muted-foreground">Aucun utilisateur</p>
            ) : (
              <div className="grid gap-2">
                {users.map((u) => {
                  const isSelf = currentUser?.id === u.id

                  return (
                    <div key={u.id} className="flex items-center gap-3 p-3 border rounded-lg">
                      <div className="flex-1 min-w-0">
                        <p className="text-sm font-medium">
                          {u.displayName}
                          {isSelf ? (
                            <span className="text-xs text-muted-foreground ml-2">(vous)</span>
                          ) : null}
                        </p>
                        <p className="text-xs text-muted-foreground">{u.username}</p>

                        {changingPasswordId === u.id ? (
                          <div className="flex gap-2 mt-2">
                            <Input
                              type="password"
                              value={newPassword}
                              onChange={(e) => setNewPassword(e.target.value)}
                              placeholder="Nouveau mot de passe (min. 8)"
                              className="h-9 text-sm"
                              autoFocus
                            />
                            <Button
                              size="sm"
                              onClick={() => void onChangePassword(u.id)}
                              disabled={loading || newPassword.length < 8}
                            >
                              OK
                            </Button>
                            <Button
                              variant="ghost"
                              size="sm"
                              onClick={() => {
                                setChangingPasswordId(null)
                                setNewPassword('')
                              }}
                            >
                              Annuler
                            </Button>
                          </div>
                        ) : null}
                      </div>

                      {changingPasswordId !== u.id ? (
                        <div className="flex gap-1 shrink-0">
                          <Button
                            variant="ghost"
                            size="icon"
                            onClick={() => {
                              setChangingPasswordId(u.id)
                              setNewPassword('')
                            }}
                            disabled={loading}
                            title="Changer le mot de passe"
                          >
                            <KeyRound className="h-4 w-4" />
                          </Button>

                          <AlertDialog>
                            <AlertDialogTrigger asChild>
                              <Button variant="ghost" size="icon" disabled={loading || isSelf} title={isSelf ? 'Vous ne pouvez pas supprimer votre propre compte' : 'Supprimer'}>
                                <Trash2 className={`h-4 w-4 ${isSelf ? 'text-muted-foreground' : 'text-destructive'}`} />
                              </Button>
                            </AlertDialogTrigger>
                            <AlertDialogContent>
                              <AlertDialogHeader>
                                <AlertDialogTitle>Supprimer cet utilisateur ?</AlertDialogTitle>
                                <AlertDialogDescription>
                                  Le compte <strong>{u.displayName}</strong> ({u.username}) sera définitivement supprimé.
                                </AlertDialogDescription>
                              </AlertDialogHeader>
                              <AlertDialogFooter>
                                <AlertDialogCancel>Annuler</AlertDialogCancel>
                                <AlertDialogAction onClick={() => void onDelete(u.id)}>
                                  Supprimer
                                </AlertDialogAction>
                              </AlertDialogFooter>
                            </AlertDialogContent>
                          </AlertDialog>
                        </div>
                      ) : null}
                    </div>
                  )
                })}
              </div>
            )}
          </CardContent>
        </Card>
      )}
    </div>
  )
}