'use server'

import { revalidatePath } from 'next/cache'
import { redirect } from 'next/navigation'
import { getAccessToken, refreshAccessToken } from '@/app/auth/actions'

const API_BASE = process.env.API_BASE_URL ?? 'http://localhost:8080'

async function getToken(): Promise<string> {
  const token = await getAccessToken()
  if (token) return token
  const fresh = await refreshAccessToken()
  if (fresh) return fresh
  redirect('/auth/login?from=/admin/users')
}

/** API'nin döndürdüğü hata yanıtından okunabilir bir mesaj çıkarır. */
function extractError(data: Record<string, unknown>, fallback: string): string {
  if (typeof data?.error === 'string' && data.error) return data.error
  if (typeof data?.message === 'string' && data.message) return data.message
  if (typeof data?.detail === 'string' && data.detail) return data.detail
  if (data?.errors && typeof data.errors === 'object') {
    const msgs = Object.values(data.errors as Record<string, string>).filter(Boolean)
    if (msgs.length > 0) return msgs.join(', ')
  }
  console.error('[API Error]', JSON.stringify(data))
  return fallback
}

export type User = {
  id: number
  username: string
  email: string
  email_verified: boolean
  is_active: boolean
  is_admin: boolean
  created_at: string
  updated_at: string
}

export type UsersResponse = {
  items: User[]
  meta: { page: number; limit: number; total: number }
}

export type UserFormState = {
  error?: string
  success?: boolean
  user?: User
  deletedId?: number
}

export async function getUsers(page = 1, limit = 10): Promise<UsersResponse> {
  let token = await getToken()
  const url = `${API_BASE}/api/v1/admin/users?page=${page}&limit=${limit}`

  const doFetch = () =>
    fetch(url, { headers: { Authorization: `Bearer ${token}` }, cache: 'no-store' })

  let res: Response
  try {
    res = await doFetch()
  } catch (error) {
    console.error('[getUsers] fetch failed', error)
    throw new Error('API sunucusuna bağlanılamadı. Backend çalışıyor mu kontrol edin.')
  }

  // Token süresi dolmuşsa yenile ve bir kez daha dene
  if (res.status === 401) {
    const fresh = await refreshAccessToken()
    if (!fresh) throw new Error('Oturum süresi doldu')
    token = fresh
    try {
      res = await doFetch()
    } catch (error) {
      console.error('[getUsers] fetch failed after refresh', error)
      throw new Error('API sunucusuna bağlanılamadı. Backend çalışıyor mu kontrol edin.')
    }
  }

  // Rate limit aşıldıysa kısa aralıkla sınırlı sayıda tekrar dene
  if (res.status === 429) {
    for (const waitMs of [500, 1000, 1500]) {
      await new Promise((r) => setTimeout(r, waitMs))
      res = await doFetch()
      if (res.ok) break
      if (res.status !== 429) break
    }
  }

  if (!res.ok) {
    console.error(`[getUsers] API error: ${res.status} ${res.statusText}`)
    if (res.status === 429) {
      throw new Error('Çok fazla istek gönderildi, lütfen birkaç saniye sonra tekrar deneyin (429)')
    }
    throw new Error(`Kullanıcılar alınamadı (${res.status})`)
  }
  return res.json()
}

export async function createUser(
  _prev: UserFormState,
  formData: FormData
): Promise<UserFormState> {
  'use server'
  try {
    const token = await getToken()
    const body = {
      username: formData.get('username') as string,
      email: formData.get('email') as string,
      password: formData.get('password') as string,
      confirm_password: formData.get('confirm_password') as string,
      is_active: formData.get('is_active') === 'true',
      is_admin: formData.get('is_admin') === 'true',
    }
    const res = await fetch(`${API_BASE}/api/v1/admin/users`, {
      method: 'POST',
      headers: {
        Authorization: `Bearer ${token}`,
        'Content-Type': 'application/json',
      },
      body: JSON.stringify(body),
    })
    if (!res.ok) {
      const data = await res.json().catch(() => ({}))
      return { error: extractError(data, 'Kullanıcı oluşturulamadı') }
    }
    revalidatePath('/admin/users')
    const created = (await res.json()) as User
    return { success: true, user: created }
  } catch (e) {
    console.error('[createUser]', e)
    return { error: 'Sunucu hatası' }
  }
}

export async function updateUser(
  id: number,
  _prev: UserFormState,
  formData: FormData
): Promise<UserFormState> {
  'use server'
  try {
    const token = await getToken()
    const body = {
      username: formData.get('username') as string,
      email: formData.get('email') as string,
      password: formData.get('password') as string,
      confirm_password: formData.get('confirm_password') as string,
      is_active: formData.get('is_active') === 'true',
      is_admin: formData.get('is_admin') === 'true',
    }
    const res = await fetch(`${API_BASE}/api/v1/admin/users/${id}`, {
      method: 'PUT',
      headers: {
        Authorization: `Bearer ${token}`,
        'Content-Type': 'application/json',
      },
      body: JSON.stringify(body),
    })
    if (!res.ok) {
      const data = await res.json().catch(() => ({}))
      return { error: extractError(data, 'Kullanıcı güncellenemedi') }
    }
    revalidatePath('/admin/users')
    const updated = (await res.json()) as User
    return { success: true, user: updated }
  } catch (e) {
    console.error('[updateUser]', e)
    return { error: 'Sunucu hatası' }
  }
}

export async function deleteUser(
  _prev: UserFormState,
  formData: FormData
): Promise<UserFormState> {
  'use server'
  try {
    const token = await getToken()
    const id = formData.get('id') as string
    const res = await fetch(`${API_BASE}/api/v1/admin/users/${id}`, {
      method: 'DELETE',
      headers: { Authorization: `Bearer ${token}` },
    })
    if (!res.ok) {
      const data = await res.json().catch(() => ({}))
      return { error: extractError(data, 'Kullanıcı silinemedi') }
    }
    revalidatePath('/admin/users')
    return { success: true, deletedId: Number(id) }
  } catch (e) {
    console.error('[deleteUser]', e)
    return { error: 'Sunucu hatası' }
  }
}

export async function changeUserStatus(
  id: number,
  isActive: boolean
): Promise<UserFormState> {
  'use server'
  try {
    const token = await getToken()
    const res = await fetch(`${API_BASE}/api/v1/admin/users/${id}/status`, {
      method: 'PATCH',
      headers: {
        Authorization: `Bearer ${token}`,
        'Content-Type': 'application/json',
      },
      body: JSON.stringify({ is_active: isActive }),
    })
    if (!res.ok) {
      const data = await res.json().catch(() => ({}))
      return { error: extractError(data, 'Durum güncellenemedi') }
    }
    revalidatePath('/admin/users')
    const updated = (await res.json()) as User
    return { success: true, user: updated }
  } catch (e) {
    console.error('[changeUserStatus]', e)
    return { error: 'Sunucu hatası' }
  }
}