const API_BASE = import.meta.env.VITE_API_URL || '/api/v1'

export interface User {
  id: number
  email: string
  username: string
  full_name: string
  employee_id: string | null
  phone: string | null
  occupation: string | null
  is_active: boolean
  created_at: string
  updated_at: string
}

export interface AuthTokens {
  access_token: string
  refresh_token: string
  token_type: string
  user: User
}

export interface RegisterPayload {
  email: string
  username: string
  password: string
  full_name: string
  employee_id?: string
  phone?: string
  occupation?: string
}

export interface LoginPayload {
  username_or_email: string
  password: string
  remember_me?: boolean
}

export interface UserUpdatePayload {
  full_name?: string
  employee_id?: string
  phone?: string
  occupation?: string
}

class ApiError extends Error {
  status: number

  constructor(message: string, status: number) {
    super(message)
    this.status = status
  }
}

function parseErrorMessage(data: unknown, status: number): string {
  if (!data || typeof data !== 'object') {
    if (status >= 500) return 'Server error. Please ensure the backend is running.'
    return 'Something went wrong'
  }

  const record = data as Record<string, unknown>
  const detail = record.detail

  if (typeof detail === 'string') return detail

  if (Array.isArray(detail)) {
    return detail
      .map((item) => {
        if (item && typeof item === 'object' && 'msg' in item) {
          return String((item as { msg: unknown }).msg)
        }
        return JSON.stringify(item)
      })
      .join(', ')
  }

  if (typeof record.message === 'string') return record.message

  if (status >= 500) return 'Server error. Please ensure the backend is running.'

  return 'Something went wrong'
}

async function request<T>(path: string, options: RequestInit = {}): Promise<T> {
  const token = localStorage.getItem('silos_access_token')
  const headers: Record<string, string> = {
    'Content-Type': 'application/json',
    ...(options.headers as Record<string, string>),
  }

  if (token) {
    headers.Authorization = `Bearer ${token}`
  }

  let response: Response
  try {
    response = await fetch(`${API_BASE}${path}`, {
      ...options,
      headers,
    })
  } catch {
    throw new ApiError('Cannot reach the server. Is the backend running on port 8000?', 0)
  }

  const data = await response.json().catch(() => ({}))

  if (!response.ok) {
    throw new ApiError(parseErrorMessage(data, response.status), response.status)
  }

  if (response.status === 204) {
    return undefined as T
  }

  return data as T
}

export const authApi = {
  register: (payload: RegisterPayload) =>
    request<User>('/auth/register', {
      method: 'POST',
      body: JSON.stringify(payload),
    }),

  login: (payload: LoginPayload) =>
    request<AuthTokens>('/auth/login', {
      method: 'POST',
      body: JSON.stringify(payload),
    }),

  me: () => request<User>('/auth/me'),

  updateMe: (payload: UserUpdatePayload) =>
    request<User>('/auth/me', {
      method: 'PATCH',
      body: JSON.stringify(payload),
    }),

  forgotPassword: (email: string) =>
    request<{ message: string; reset_token?: string }>('/auth/forgot-password', {
      method: 'POST',
      body: JSON.stringify({ email }),
    }),

  resetPassword: (token: string, new_password: string) =>
    request<{ message: string }>('/auth/reset-password', {
      method: 'POST',
      body: JSON.stringify({ token, new_password }),
    }),
}

export function saveAuth(tokens: AuthTokens) {
  localStorage.setItem('silos_access_token', tokens.access_token)
  localStorage.setItem('silos_refresh_token', tokens.refresh_token)
  localStorage.setItem('silos_user', JSON.stringify(tokens.user))
}

export function clearAuth() {
  localStorage.removeItem('silos_access_token')
  localStorage.removeItem('silos_refresh_token')
  localStorage.removeItem('silos_user')
}

export function getStoredUser(): User | null {
  const raw = localStorage.getItem('silos_user')
  if (!raw) return null
  try {
    return JSON.parse(raw) as User
  } catch {
    return null
  }
}

export { ApiError }

export interface DocumentMember {
  user_id: number
  role: 'editor' | 'viewer'
  name: string
  email: string
}

export interface ApiDocument {
  id: string
  type: 'shed' | 'silo' | 'sketch' | 'stead'
  title: string
  template_id?: string | null
  stead_id?: string | null
  content: Record<string, unknown>
  created_by: string
  created_at: string
  updated_at: string
  starred: boolean
  last_visited_at: string | null
  owner_id?: number | null
  visibility?: 'private' | 'members'
  members?: DocumentMember[]
}

export interface DocumentCreatePayload {
  type: 'shed' | 'silo' | 'sketch' | 'stead'
  title: string
  content?: Record<string, unknown>
  template_id?: string
  stead_id?: string
}

export interface DocumentUpdatePayload {
  title?: string
  content?: Record<string, unknown>
  starred?: boolean
}

export const documentsApi = {
  list: (params?: {
    type?: string
    stead_id?: string
    starred?: boolean
    sort?: 'updated_at' | 'last_visited_at'
  }) => {
    const search = new URLSearchParams()
    if (params?.type) search.set('type', params.type)
    if (params?.stead_id) search.set('stead_id', params.stead_id)
    if (params?.starred !== undefined) search.set('starred', String(params.starred))
    if (params?.sort) search.set('sort', params.sort)
    const qs = search.toString()
    return request<ApiDocument[]>(`/documents${qs ? `?${qs}` : ''}`)
  },

  search: (q: string) =>
    request<ApiDocument[]>(`/documents/search?q=${encodeURIComponent(q)}`),

  get: (id: string) => request<ApiDocument>(`/documents/${id}`),

  create: (payload: DocumentCreatePayload) =>
    request<ApiDocument>('/documents', {
      method: 'POST',
      body: JSON.stringify(payload),
    }),

  update: (id: string, payload: DocumentUpdatePayload) =>
    request<ApiDocument>(`/documents/${id}`, {
      method: 'PATCH',
      body: JSON.stringify(payload),
    }),

  visit: (id: string) =>
    request<ApiDocument>(`/documents/${id}/visit`, { method: 'POST' }),

  share: (id: string, email_or_username: string, role: 'editor' | 'viewer' = 'editor') =>
    request<ApiDocument>(`/documents/${id}/share`, {
      method: 'POST',
      body: JSON.stringify({ email_or_username, role }),
    }),

  unshare: (id: string, userId: number) =>
    request<ApiDocument>(`/documents/${id}/share/${userId}`, { method: 'DELETE' }),

  delete: (id: string) =>
    request<void>(`/documents/${id}`, { method: 'DELETE' }),
}