feat: add persistent task operations and API

lib/tasks.ts

@@ -0,0 +1,223 @@
+import type {
+  Task,
+  TaskInput,
+  TaskSort,
+  TaskStatus,
+  TaskUpdate,
+} from "@/types/task";
+import { getDatabase } from "./db";
+
+type TaskRow = {
+  id: number;
+  title: string;
+  description: string;
+  due_date: string;
+  topic: string;
+  status: TaskStatus;
+  archived_at: string | null;
+  created_at: string;
+  updated_at: string;
+};
+
+const statuses: TaskStatus[] = ["Todo", "In-Progress", "Complete"];
+
+function isTaskStatus(value: unknown): value is TaskStatus {
+  return typeof value === "string" && statuses.includes(value as TaskStatus);
+}
+
+function todayIsoDate() {
+  const now = new Date();
+  const year = now.getFullYear();
+  const month = String(now.getMonth() + 1).padStart(2, "0");
+  const day = String(now.getDate()).padStart(2, "0");
+
+  return `${year}-${month}-${day}`;
+}
+
+function isDateInput(value: unknown): value is string {
+  return typeof value === "string" && /^\d{4}-\d{2}-\d{2}$/.test(value);
+}
+
+function cleanString(value: unknown, field: string) {
+  if (typeof value !== "string") {
+    throw new Error(`${field} must be text.`);
+  }
+
+  return value.trim();
+}
+
+function normalizeTaskInput(input: Partial<TaskInput>): TaskInput {
+  const title = cleanString(input.title, "Title");
+  const description =
+    typeof input.description === "string" ? input.description.trim() : "";
+  const dueDate = input.dueDate;
+  const topic = cleanString(input.topic, "Topic");
+
+  if (!title) {
+    throw new Error("Title is required.");
+  }
+
+  if (!topic) {
+    throw new Error("Topic is required.");
+  }
+
+  if (!isDateInput(dueDate)) {
+    throw new Error("Due date must use YYYY-MM-DD format.");
+  }
+
+  return {
+    title,
+    description,
+    dueDate,
+    topic,
+  };
+}
+
+function toTask(row: TaskRow): Task {
+  return {
+    id: row.id,
+    title: row.title,
+    description: row.description,
+    dueDate: row.due_date,
+    topic: row.topic,
+    status: row.status,
+    archivedAt: row.archived_at,
+    createdAt: row.created_at,
+    updatedAt: row.updated_at,
+    isOverdue:
+      !row.archived_at && row.status !== "Complete" && row.due_date < todayIsoDate(),
+  };
+}
+
+function rowToTask(row: unknown) {
+  if (!row) {
+    return null;
+  }
+
+  return toTask(row as TaskRow);
+}
+
+function sortClause(sort: TaskSort) {
+  if (sort === "topic") {
+    return "topic COLLATE NOCASE ASC, due_date ASC, id ASC";
+  }
+
+  if (sort === "status") {
+    return "CASE status WHEN 'Todo' THEN 1 WHEN 'In-Progress' THEN 2 ELSE 3 END ASC, due_date ASC, id ASC";
+  }
+
+  if (sort === "dueDate") {
+    return "due_date ASC, topic COLLATE NOCASE ASC, id ASC";
+  }
+
+  return "created_at DESC, id DESC";
+}
+
+export function listTasks({
+  includeArchived = false,
+  sort = "createdAt",
+}: {
+  includeArchived?: boolean;
+  sort?: TaskSort;
+} = {}) {
+  const database = getDatabase();
+  const where = includeArchived ? "" : "WHERE archived_at IS NULL";
+  const rows = database
+    .prepare(`SELECT * FROM tasks ${where} ORDER BY ${sortClause(sort)}`)
+    .all() as TaskRow[];
+
+  return rows.map(toTask);
+}
+
+export function getTask(id: number) {
+  const database = getDatabase();
+  return rowToTask(database.prepare("SELECT * FROM tasks WHERE id = ?").get(id));
+}
+
+export function createTask(input: Partial<TaskInput>) {
+  const database = getDatabase();
+  const task = normalizeTaskInput(input);
+  const result = database
+    .prepare(
+      `INSERT INTO tasks (title, description, due_date, topic, status)
+       VALUES (?, ?, ?, ?, 'Todo')`
+    )
+    .run(task.title, task.description, task.dueDate, task.topic);
+
+  const created = getTask(Number(result.lastInsertRowid));
+
+  if (!created) {
+    throw new Error("Task could not be created.");
+  }
+
+  return created;
+}
+
+export function updateTask(id: number, updates: TaskUpdate) {
+  const current = getTask(id);
+
+  if (!current) {
+    throw new Error("Task not found.");
+  }
+
+  const nextStatus = updates.status ?? current.status;
+
+  if (!isTaskStatus(nextStatus)) {
+    throw new Error("Status must be Todo, In-Progress, or Complete.");
+  }
+
+  const nextTask = normalizeTaskInput({
+    title: updates.title ?? current.title,
+    description: updates.description ?? current.description,
+    dueDate: updates.dueDate ?? current.dueDate,
+    topic: updates.topic ?? current.topic,
+  });
+
+  const database = getDatabase();
+  database
+    .prepare(
+      `UPDATE tasks
+       SET title = ?, description = ?, due_date = ?, topic = ?, status = ?, updated_at = CURRENT_TIMESTAMP
+       WHERE id = ?`
+    )
+    .run(
+      nextTask.title,
+      nextTask.description,
+      nextTask.dueDate,
+      nextTask.topic,
+      nextStatus,
+      id
+    );
+
+  const updated = getTask(id);
+
+  if (!updated) {
+    throw new Error("Task could not be updated.");
+  }
+
+  return updated;
+}
+
+export function archiveTask(id: number) {
+  if (!getTask(id)) {
+    throw new Error("Task not found.");
+  }
+
+  const database = getDatabase();
+  database
+    .prepare(
+      `UPDATE tasks
+       SET archived_at = COALESCE(archived_at, CURRENT_TIMESTAMP),
+           updated_at = CURRENT_TIMESTAMP
+       WHERE id = ?`
+    )
+    .run(id);
+
+  const archived = getTask(id);
+
+  if (!archived) {
+    throw new Error("Task could not be archived.");
+  }
+
+  return archived;
+}