const API_BASE = '/api'

async function parseResponse(response) {
  if (response.status === 204) {
    return null
  }
  const data = await response.json().catch(() => null)
  if (!response.ok) {
    const message = data?.message || data?.['hydra:description'] || response.statusText
    throw new Error(message)
  }
  return data
}

export async function apiFetch(path, options = {}) {
  const token = localStorage.getItem('speedbb_token')
  const headers = {
    Accept: 'application/json',
    ...(options.headers || {}),
  }
  if (!(options.body instanceof FormData)) {
    headers['Content-Type'] = 'application/json'
  }
  if (token) {
    headers.Authorization = `Bearer ${token}`
  }
  const response = await fetch(`${API_BASE}${path}`, {
    ...options,
    headers,
  })
  return parseResponse(response)
}

export async function getCollection(path) {
  const data = await apiFetch(path)
  return data?.['hydra:member'] || []
}

export async function login(email, password) {
  return apiFetch('/login', {
    method: 'POST',
    body: JSON.stringify({ email, password }),
  })
}

export async function registerUser({ email, username, plainPassword }) {
  return apiFetch('/users', {
    method: 'POST',
    body: JSON.stringify({ email, username, plainPassword }),
  })
}

export async function listRootForums() {
  return getCollection('/forums?parent[exists]=false')
}

export async function listForumsByParent(parentId) {
  return getCollection(`/forums?parent=/api/forums/${parentId}`)
}

export async function getForum(id) {
  return apiFetch(`/forums/${id}`)
}

export async function listThreadsByForum(forumId) {
  return getCollection(`/threads?forum=/api/forums/${forumId}`)
}

export async function getThread(id) {
  return apiFetch(`/threads/${id}`)
}

export async function listPostsByThread(threadId) {
  return getCollection(`/posts?thread=/api/threads/${threadId}`)
}

export async function createThread({ title, body, forumId }) {
  return apiFetch('/threads', {
    method: 'POST',
    body: JSON.stringify({
      title,
      body,
      forum: `/api/forums/${forumId}`,
    }),
  })
}

export async function createPost({ body, threadId }) {
  return apiFetch('/posts', {
    method: 'POST',
    body: JSON.stringify({
      body,
      thread: `/api/threads/${threadId}`,
    }),
  })
}