import type { List, Task, TaskDetail, TaskItem, TaskComment, AppConfig, AppStatus, Category, Project, ProjectDetail } from './types'

const BASE = '/tasks/api'

async function request<T>(path: string, opts: RequestInit = {}): Promise<T> {
  const res = await fetch(`${BASE}${path}`, {
    credentials: 'include',
    headers: { 'Content-Type': 'application/json', ...opts.headers },
    ...opts,
  })
  if (res.status === 401) {
    ;(window.top ?? window).location.href = '/login'
    throw new Error('Unauthenticated')
  }
  if (!res.ok) {
    const err = await res.json().catch(() => ({ error: res.statusText }))
    throw new Error(err.error || `Request failed: ${res.status}`)
  }
  if (res.status === 204) return undefined as T
  return res.json()
}

// ── Lists ────────────────────────────────────────────────────
export function fetchLists(includeArchived = false): Promise<List[]> {
  return request(`/lists${includeArchived ? '?archived=1' : ''}`)
}
export function createList(body: { name: string; colour?: string; icon?: string }): Promise<List> {
  return request('/lists', { method: 'POST', body: JSON.stringify(body) })
}
export function updateList(id: number, body: Partial<List>): Promise<List> {
  return request(`/lists/${id}`, { method: 'PATCH', body: JSON.stringify(body) })
}
export function deleteList(id: number): Promise<{ ok: boolean }> {
  return request(`/lists/${id}`, { method: 'DELETE' })
}

// ── Tasks ────────────────────────────────────────────────────
export interface TaskFilters {
  list_id?: number
  view?: 'today' | 'assigned' | 'shared' | 'all'
  status?: string
  category_id?: number
  project_id?: number
}
export function fetchTasks(params: TaskFilters = {}): Promise<Task[]> {
  const qs = new URLSearchParams()
  for (const [k, v] of Object.entries(params)) if (v !== undefined) qs.set(k, String(v))
  const s = qs.toString()
  return request(`/tasks${s ? `?${s}` : ''}`)
}
export function fetchTask(id: number): Promise<TaskDetail> {
  return request(`/tasks/${id}`)
}
export function createTask(body: Record<string, unknown>): Promise<Task> {
  return request('/tasks', { method: 'POST', body: JSON.stringify(body) })
}
export function updateTask(id: number, body: Record<string, unknown>): Promise<Task> {
  return request(`/tasks/${id}`, { method: 'PATCH', body: JSON.stringify(body) })
}
export function deleteTask(id: number): Promise<{ ok: boolean }> {
  return request(`/tasks/${id}`, { method: 'DELETE' })
}
export function reorderTasks(ids: number[]): Promise<{ ok: boolean }> {
  return request('/tasks/reorder', { method: 'POST', body: JSON.stringify({ ids }) })
}
export function reallocateTask(id: number, to: string): Promise<Task> {
  return request(`/tasks/${id}/reallocate`, { method: 'POST', body: JSON.stringify({ to }) })
}

// ── Tags (share/watch) ───────────────────────────────────────
export function tagTask(id: number, email: string): Promise<{ ok: boolean }> {
  return request(`/tasks/${id}/tags`, { method: 'POST', body: JSON.stringify({ email }) })
}
export function untagTask(id: number, email: string): Promise<{ ok: boolean }> {
  return request(`/tasks/${id}/tags/${encodeURIComponent(email)}`, { method: 'DELETE' })
}

// ── Statuses ─────────────────────────────────────────────────
export function fetchStatuses(): Promise<AppStatus[]> {
  return request('/statuses')
}
export function createStatus(body: { label: string; value: string; is_hold?: boolean }): Promise<AppStatus> {
  return request('/statuses', { method: 'POST', body: JSON.stringify(body) })
}
export function updateStatus(id: number, body: Partial<AppStatus>): Promise<AppStatus> {
  return request(`/statuses/${id}`, { method: 'PATCH', body: JSON.stringify(body) })
}
export function deleteStatus(id: number): Promise<{ ok: boolean }> {
  return request(`/statuses/${id}`, { method: 'DELETE' })
}

// ── Categories ───────────────────────────────────────────────
export function fetchCategories(): Promise<Category[]> {
  return request('/categories')
}
export function createCategory(body: { name: string; colour?: string }): Promise<Category> {
  return request('/categories', { method: 'POST', body: JSON.stringify(body) })
}
export function updateCategory(id: number, body: Partial<Category>): Promise<Category> {
  return request(`/categories/${id}`, { method: 'PATCH', body: JSON.stringify(body) })
}
export function deleteCategory(id: number): Promise<{ ok: boolean }> {
  return request(`/categories/${id}`, { method: 'DELETE' })
}

// ── Projects ─────────────────────────────────────────────────
export function fetchProjects(): Promise<Project[]> {
  return request('/projects')
}
export function fetchProject(id: number): Promise<ProjectDetail> {
  return request(`/projects/${id}`)
}
export function createProject(body: { name: string; description?: string; colour?: string }): Promise<Project> {
  return request('/projects', { method: 'POST', body: JSON.stringify(body) })
}
export function updateProject(id: number, body: Partial<Project>): Promise<Project> {
  return request(`/projects/${id}`, { method: 'PATCH', body: JSON.stringify(body) })
}
export function deleteProject(id: number): Promise<{ ok: boolean }> {
  return request(`/projects/${id}`, { method: 'DELETE' })
}

// ── Checklist items ──────────────────────────────────────────
export function addItem(taskId: number, label: string): Promise<TaskItem> {
  return request(`/tasks/${taskId}/items`, { method: 'POST', body: JSON.stringify({ label }) })
}
export function updateItem(itemId: number, body: Partial<TaskItem>): Promise<TaskItem> {
  return request(`/tasks/items/${itemId}`, { method: 'PATCH', body: JSON.stringify(body) })
}
export function deleteItem(itemId: number): Promise<{ ok: boolean }> {
  return request(`/tasks/items/${itemId}`, { method: 'DELETE' })
}

// ── Comments ─────────────────────────────────────────────────
export function addComment(taskId: number, body: string): Promise<TaskComment> {
  return request(`/tasks/${taskId}/comments`, { method: 'POST', body: JSON.stringify({ body }) })
}

// ── Config ───────────────────────────────────────────────────
export function fetchConfig(): Promise<AppConfig> {
  return request('/config')
}
export function updateConfig(key: string, value: unknown): Promise<{ ok: boolean }> {
  return request(`/config/${key}`, { method: 'PUT', body: JSON.stringify({ value }) })
}