import type { Task, Project, ProjectWithTasks, VelocityStats, Recurrence, Todo, TodoPriority } from "./types";

const BASE = "/api/tasks";

export async function fetchTasks(): Promise<Task[]> {
  const res = await fetch(BASE, { credentials: "include" });
  if (!res.ok) throw new Error(res.status === 401 ? "Unauthorized" : "Failed to fetch tasks");
  return res.json();
}

export async function updateTask(
  id: string,
  updates: Record<string, any>,
  token?: string
): Promise<Task> {
  const headers: Record<string, string> = { "Content-Type": "application/json" };
  if (token) headers["Authorization"] = `Bearer ${token}`;
  const res = await fetch(`${BASE}/${id}`, {
    method: "PATCH",
    credentials: "include",
    headers,
    body: JSON.stringify(updates),
  });
  if (!res.ok) throw new Error("Failed to update task");
  return res.json();
}

export async function reorderTasks(ids: string[], token?: string): Promise<void> {
  const headers: Record<string, string> = { "Content-Type": "application/json" };
  if (token) headers["Authorization"] = `Bearer ${token}`;
  const res = await fetch(`${BASE}/reorder`, {
    method: "PATCH",
    credentials: "include",
    headers,
    body: JSON.stringify({ ids }),
  });
  if (!res.ok) throw new Error("Failed to reorder tasks");
}

export async function createTask(
  task: { title: string; description?: string; source?: string; priority?: string; status?: string; projectId?: string; dueDate?: string; estimatedHours?: number; recurrence?: Recurrence | null },
  token?: string
): Promise<Task> {
  const headers: Record<string, string> = { "Content-Type": "application/json" };
  if (token) headers["Authorization"] = `Bearer ${token}`;
  const res = await fetch(BASE, {
    method: "POST",
    credentials: "include",
    headers,
    body: JSON.stringify(task),
  });
  if (!res.ok) throw new Error("Failed to create task");
  return res.json();
}

export async function deleteTask(id: string, token?: string): Promise<void> {
  const headers: Record<string, string> = {};
  if (token) headers["Authorization"] = `Bearer ${token}`;
  const res = await fetch(`${BASE}/${id}`, {
    method: "DELETE",
    credentials: "include",
    headers,
  });
  if (!res.ok) throw new Error("Failed to delete task");
}

// ─── Velocity Stats ───

export async function fetchVelocityStats(): Promise<VelocityStats> {
  const res = await fetch(`${BASE}/stats/velocity`, { credentials: "include" });
  if (!res.ok) throw new Error("Failed to fetch velocity stats");
  return res.json();
}

// ─── Projects API ───

const PROJECTS_BASE = "/api/projects";

export async function fetchProjects(): Promise<Project[]> {
  const res = await fetch(PROJECTS_BASE, { credentials: "include" });
  if (!res.ok) throw new Error(res.status === 401 ? "Unauthorized" : "Failed to fetch projects");
  return res.json();
}

export async function fetchProject(id: string): Promise<ProjectWithTasks> {
  const res = await fetch(`${PROJECTS_BASE}/${id}`, { credentials: "include" });
  if (!res.ok) throw new Error("Failed to fetch project");
  return res.json();
}

export async function createProject(
  project: { name: string; description?: string; context?: string; repos?: string[]; links?: { label: string; url: string }[] }
): Promise<Project> {
  const res = await fetch(PROJECTS_BASE, {
    method: "POST",
    credentials: "include",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify(project),
  });
  if (!res.ok) throw new Error("Failed to create project");
  return res.json();
}

export async function updateProject(
  id: string,
  updates: Record<string, any>
): Promise<Project> {
  const res = await fetch(`${PROJECTS_BASE}/${id}`, {
    method: "PATCH",
    credentials: "include",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify(updates),
  });
  if (!res.ok) throw new Error("Failed to update project");
  return res.json();
}

export async function deleteProject(id: string): Promise<void> {
  const res = await fetch(`${PROJECTS_BASE}/${id}`, {
    method: "DELETE",
    credentials: "include",
  });
  if (!res.ok) throw new Error("Failed to delete project");
}

// Subtasks
export async function addSubtask(taskId: string, title: string): Promise<Task> {
  const res = await fetch(`${BASE}/${taskId}/subtasks`, {
    method: "POST",
    credentials: "include",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({ title }),
  });
  if (!res.ok) throw new Error("Failed to add subtask");
  return res.json();
}

export async function toggleSubtask(taskId: string, subtaskId: string, completed: boolean): Promise<Task> {
  const res = await fetch(`${BASE}/${taskId}/subtasks/${subtaskId}`, {
    method: "PATCH",
    credentials: "include",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({ completed }),
  });
  if (!res.ok) throw new Error("Failed to toggle subtask");
  return res.json();
}

export async function deleteSubtask(taskId: string, subtaskId: string): Promise<Task> {
  const res = await fetch(`${BASE}/${taskId}/subtasks/${subtaskId}`, {
    method: "DELETE",
    credentials: "include",
  });
  if (!res.ok) throw new Error("Failed to delete subtask");
  return res.json();
}

// Progress Notes
export async function addProgressNote(taskId: string, note: string): Promise<Task> {
  const res = await fetch(`${BASE}/${taskId}/notes`, {
    method: "POST",
    credentials: "include",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({ note }),
  });
  if (!res.ok) throw new Error("Failed to add progress note");
  return res.json();
}

// ─── Comments API ───

export interface TaskComment {
  id: string;
  taskId: string;
  authorId: string | null;
  authorName: string;
  content: string;
  createdAt: string;
}

export async function fetchComments(taskId: string): Promise<TaskComment[]> {
  const res = await fetch(`${BASE}/${taskId}/comments`, { credentials: "include" });
  if (!res.ok) throw new Error("Failed to fetch comments");
  return res.json();
}

export async function addComment(taskId: string, content: string): Promise<TaskComment> {
  const res = await fetch(`${BASE}/${taskId}/comments`, {
    method: "POST",
    credentials: "include",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({ content }),
  });
  if (!res.ok) throw new Error("Failed to add comment");
  return res.json();
}

export async function deleteComment(taskId: string, commentId: string): Promise<void> {
  const res = await fetch(`${BASE}/${taskId}/comments/${commentId}`, {
    method: "DELETE",
    credentials: "include",
  });
  if (!res.ok) throw new Error("Failed to delete comment");
}

// Admin API
export async function fetchUsers(): Promise<any[]> {
  const res = await fetch("/api/admin/users", { credentials: "include" });
  if (!res.ok) throw new Error("Failed to fetch users");
  return res.json();
}

export async function updateUserRole(userId: string, role: string): Promise<any> {
  const res = await fetch(`/api/admin/users/${userId}/role`, {
    method: "PATCH",
    credentials: "include",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({ role }),
  });
  if (!res.ok) throw new Error("Failed to update user role");
  return res.json();
}

export async function deleteUser(userId: string): Promise<void> {
  const res = await fetch(`/api/admin/users/${userId}`, {
    method: "DELETE",
    credentials: "include",
  });
  if (!res.ok) throw new Error("Failed to delete user");
}

// ─── Todos API ───

const TODOS_BASE = "/api/todos";

export async function fetchTodos(params?: { completed?: string; category?: string }): Promise<Todo[]> {
  const url = new URL(TODOS_BASE, window.location.origin);
  if (params?.completed) url.searchParams.set("completed", params.completed);
  if (params?.category) url.searchParams.set("category", params.category);
  const res = await fetch(url.toString(), { credentials: "include" });
  if (!res.ok) throw new Error(res.status === 401 ? "Unauthorized" : "Failed to fetch todos");
  return res.json();
}

export async function fetchTodoCategories(): Promise<string[]> {
  const res = await fetch(`${TODOS_BASE}/categories`, { credentials: "include" });
  if (!res.ok) throw new Error("Failed to fetch categories");
  return res.json();
}

export async function createTodo(todo: {
  title: string;
  description?: string;
  priority?: TodoPriority;
  category?: string;
  dueDate?: string | null;
}): Promise<Todo> {
  const res = await fetch(TODOS_BASE, {
    method: "POST",
    credentials: "include",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify(todo),
  });
  if (!res.ok) throw new Error("Failed to create todo");
  return res.json();
}

export async function updateTodo(id: string, updates: Partial<{
  title: string;
  description: string;
  priority: TodoPriority;
  category: string | null;
  dueDate: string | null;
  isCompleted: boolean;
  sortOrder: number;
}>): Promise<Todo> {
  const res = await fetch(`${TODOS_BASE}/${id}`, {
    method: "PATCH",
    credentials: "include",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify(updates),
  });
  if (!res.ok) throw new Error("Failed to update todo");
  return res.json();
}

export async function toggleTodo(id: string): Promise<Todo> {
  const res = await fetch(`${TODOS_BASE}/${id}/toggle`, {
    method: "PATCH",
    credentials: "include",
  });
  if (!res.ok) throw new Error("Failed to toggle todo");
  return res.json();
}

export async function deleteTodo(id: string): Promise<void> {
  const res = await fetch(`${TODOS_BASE}/${id}`, {
    method: "DELETE",
    credentials: "include",
  });
  if (!res.ok) throw new Error("Failed to delete todo");
}