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)) {
    if (!headers['Content-Type']) {
      headers['Content-Type'] = 'application/json'
    }
  }
  if (token) {
    headers.Authorization = `Bearer ${token}`
  }
  const response = await fetch(`${API_BASE}${path}`, {
    ...options,
    headers,
  })
  if (response.status === 401) {
    localStorage.removeItem('speedbb_token')
    localStorage.removeItem('speedbb_email')
    localStorage.removeItem('speedbb_user_id')
    localStorage.removeItem('speedbb_roles')
    window.dispatchEvent(new Event('speedbb-unauthorized'))
  }
  return parseResponse(response)
}

export async function getCollection(path) {
  const data = await apiFetch(path)
  if (Array.isArray(data)) {
    return data
  }
  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('/register', {
    method: 'POST',
    body: JSON.stringify({ email, username, plainPassword }),
  })
}

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

export async function listAllForums() {
  return getCollection('/forums?pagination=false')
}

export async function fetchVersion() {
  return apiFetch('/version')
}

export async function fetchSetting(key) {
  const cacheBust = Date.now()
  const data = await apiFetch(
    `/settings?key=${encodeURIComponent(key)}&pagination=false&_=${cacheBust}`,
    { cache: 'no-store' }
  )
  if (Array.isArray(data)) {
    return data[0] || null
  }
  return data?.['hydra:member']?.[0] || null
}

export async function saveSetting(key, value) {
  return apiFetch('/settings', {
    method: 'POST',
    body: JSON.stringify({ key, value }),
  })
}

export async function uploadLogo(file) {
  const body = new FormData()
  body.append('file', file)
  return apiFetch('/uploads/logo', {
    method: 'POST',
    body,
  })
}

export async function uploadFavicon(file) {
  const body = new FormData()
  body.append('file', file)
  return apiFetch('/uploads/favicon', {
    method: 'POST',
    body,
  })
}

export async function fetchUserSetting(key) {
  const data = await getCollection(`/user-settings?key=${encodeURIComponent(key)}&pagination=false`)
  return data[0] || null
}

export async function saveUserSetting(key, value) {
  return apiFetch('/user-settings', {
    method: 'POST',
    body: JSON.stringify({ key, value }),
  })
}

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

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

export async function createForum({ name, description, type, parentId }) {
  return apiFetch('/forums', {
    method: 'POST',
    body: JSON.stringify({
      name,
      description,
      type,
      parent: parentId ? `/api/forums/${parentId}` : null,
    }),
  })
}

export async function updateForum(id, { name, description, type, parentId }) {
  return apiFetch(`/forums/${id}`, {
    method: 'PATCH',
    headers: {
      'Content-Type': 'application/merge-patch+json',
    },
    body: JSON.stringify({
      name,
      description,
      type,
      parent: parentId ? `/api/forums/${parentId}` : null,
    }),
  })
}

export async function deleteForum(id) {
  return apiFetch(`/forums/${id}`, {
    method: 'DELETE',
  })
}

export async function reorderForums(parentId, orderedIds) {
  return apiFetch('/forums/reorder', {
    method: 'POST',
    body: JSON.stringify({
      parentId,
      orderedIds,
    }),
  })
}

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

export async function listThreads() {
  return getCollection('/threads')
}

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

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

export async function listUsers() {
  return getCollection('/users')
}

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}`,
    }),
  })
}