Project management on Next.js 16 (App Router), MySQL 8 and Better Auth

import { drizzle } from "drizzle-orm/mysql2";
import mysql from "mysql2/promise";

// ponytail: single module-level pool; the runtime + mysql2's pool handle concurrency,
// so no globalThis singleton dance needed.
const pool = mysql.createPool(process.env.DATABASE_URL!);

export const db = drizzle({ client: pool });

import { boolean, mysqlTable, text, timestamp, varchar } from "drizzle-orm/mysql-core";

export const user = mysqlTable("user", {
  id: varchar("id", { length: 255 }).primaryKey(),
  name: text("name").notNull(),
  email: varchar("email", { length: 255 }).notNull().unique(),
  emailVerified: boolean("email_verified").notNull().default(false),
  image: text("image"),
  createdAt: timestamp("created_at").notNull().defaultNow(),
  updatedAt: timestamp("updated_at").notNull().defaultNow(),
});

export const session = mysqlTable("session", {
  id: varchar("id", { length: 255 }).primaryKey(),
  expiresAt: timestamp("expires_at").notNull(),
  token: varchar("token", { length: 255 }).notNull().unique(),
  createdAt: timestamp("created_at").notNull().defaultNow(),
  updatedAt: timestamp("updated_at").notNull(),
  ipAddress: text("ip_address"),
  userAgent: text("user_agent"),
  userId: varchar("user_id", { length: 255 })
    .notNull()
    .references(() => user.id, { onDelete: "cascade" }),
});

export const account = mysqlTable("account", {
  id: varchar("id", { length: 255 }).primaryKey(),
  accountId: text("account_id").notNull(),
  providerId: text("provider_id").notNull(),
  userId: varchar("user_id", { length: 255 })
    .notNull()
    .references(() => user.id, { onDelete: "cascade" }),
  accessToken: text("access_token"),
  refreshToken: text("refresh_token"),
  idToken: text("id_token"),
  accessTokenExpiresAt: timestamp("access_token_expires_at"),
  refreshTokenExpiresAt: timestamp("refresh_token_expires_at"),
  scope: text("scope"),
  password: text("password"),
  createdAt: timestamp("created_at").notNull().defaultNow(),
  updatedAt: timestamp("updated_at").notNull(),
});

export const verification = mysqlTable("verification", {
  id: varchar("id", { length: 255 }).primaryKey(),
  identifier: text("identifier").notNull(),
  value: text("value").notNull(),
  expiresAt: timestamp("expires_at").notNull(),
  createdAt: timestamp("created_at").notNull().defaultNow(),
  updatedAt: timestamp("updated_at").notNull().defaultNow(),
});

// Better Auth instance (self-hosted, Next.js 16 (App Router)).
import { betterAuth } from "better-auth";
import { drizzleAdapter } from "better-auth/adapters/drizzle";
// Reuse the SAME postgres-js/Drizzle client the db slice exported in
// src/lib/db.ts — Better Auth shares the pooled `DATABASE_URL` connection.
import { db } from "./db";
import * as authSchema from "@/db/auth-schema";

export const auth = betterAuth({
  // Drizzle adapter over the shared client. The schema is passed HERE (not into
  // drizzle()) — it is the only consumer that needs it, so the db client stays
  // schema-less. ponytail: do NOT enable experimental.joins; it is the one option
  // that would make the adapter reach into db._.fullSchema.
  // ponytail: usePlural stays false (the default) — with it true Better Auth would
  // look for `sessions`/`accounts` and could bind to the analytics/ledger app-type tables.
  database: drizzleAdapter(db, { provider: "mysql", schema: authSchema }),
  // ponytail: email+password is the shortest real auth that works out of
  // the box — add socialProviders / plugins here when the app needs them.
  emailAndPassword: { enabled: true },
  secret: process.env.BETTER_AUTH_SECRET,
  baseURL: process.env.BETTER_AUTH_URL,
});

export type Session = typeof auth.$Infer.Session;

// Mount Better Auth on Next's route layer.
import { toNextJsHandler } from "better-auth/next-js";
import { auth } from "@/lib/auth";

export const { GET, POST } = toNextJsHandler(auth);

// Session-protection proxy for Next.js 16 (App Router) (Next 16 renamed middleware.ts → proxy.ts).
// ponytail: getSessionCookie only checks the cookie EXISTS (no DB hit at
// the Edge runtime) — do the real auth.api.getSession() check inside
// protected Server Components / route handlers. This just bounces
// logged-out users before render.
import { NextResponse, type NextRequest } from "next/server";
import { getSessionCookie } from "better-auth/cookies";

export function proxy(request: NextRequest) {
  const sessionCookie = getSessionCookie(request);
  if (!sessionCookie) {
    return NextResponse.redirect(new URL("/sign-in", request.url));
  }
  return NextResponse.next();
}

export const config = {
  // ponytail: guard the SaaS app surface; widen the matcher per app-type.
  matcher: ["/dashboard/:path*", "/settings/:path*"],
};

// === file: src/db/schema.ts ===
import { relations, sql } from "drizzle-orm";
import {
  check,
  index,
  mysqlTable,
  text,
  timestamp,
  unique,
  varchar,
} from "drizzle-orm/mysql-core";
// Better Auth owns identity; we only reference its `user` table by id.
import { user } from "./auth-schema";

export type ProjectStatus = "active" | "archived";
export type TaskStatus = "todo" | "in_progress" | "done";
export type TaskPriority = "low" | "medium" | "high" | "urgent";

/** Top-level container. Every task/label hangs off a project; the owner is a
 *  Better Auth user referenced by id (varchar), never redeclared here. */
export const projects = mysqlTable(
  "projects",
  {
    id: varchar("id", { length: 36 }).primaryKey(),
    // Better Auth's user.id is text — match it as varchar(255).
    ownerId: varchar("owner_id", { length: 255 })
      .notNull()
      .references(() => user.id, { onDelete: "cascade" }),
    name: text("name").notNull(),
    status: varchar("status", { length: 32 })
      .$type<ProjectStatus>()
      .notNull()
      .default("active"),
    createdAt: timestamp("created_at").notNull().defaultNow(),
  },
  (t) => [
    index("idx_project_owner").on(t.ownerId),
    check(
      "projects_status_check",
      sql`${t.status} in ('active','archived')`,
    ),
  ],
);

/** The unit of work. Scoped to a project; status/priority drive the board, and
 *  the project+status index backs the "tasks in this column" query. */
export const tasks = mysqlTable(
  "tasks",
  {
    id: varchar("id", { length: 36 }).primaryKey(),
    projectId: varchar("project_id", { length: 36 })
      .notNull()
      .references(() => projects.id, { onDelete: "cascade" }),
    title: text("title").notNull(),
    status: varchar("status", { length: 32 })
      .$type<TaskStatus>()
      .notNull()
      .default("todo"),
    priority: varchar("priority", { length: 32 })
      .$type<TaskPriority>()
      .notNull()
      .default("medium"),
    dueDate: timestamp("due_date"),
    createdAt: timestamp("created_at").notNull().defaultNow(),
  },
  (t) => [
    // Drives the board: tasks in a project, grouped by column/status.
    index("idx_task_project_status").on(t.projectId, t.status),
    check(
      "tasks_status_check",
      sql`${t.status} in ('todo','in_progress','done')`,
    ),
    check(
      "tasks_priority_check",
      sql`${t.priority} in ('low','medium','high','urgent')`,
    ),
  ],
);

/** task <-> user assignment. The composite unique is the assignment identity
 *  (a user is assigned to a task at most once); the user index backs "my tasks". */
export const taskAssignees = mysqlTable(
  "task_assignees",
  {
    id: varchar("id", { length: 36 }).primaryKey(),
    taskId: varchar("task_id", { length: 36 })
      .notNull()
      .references(() => tasks.id, { onDelete: "cascade" }),
    assigneeId: varchar("assignee_id", { length: 255 })
      .notNull()
      .references(() => user.id, { onDelete: "cascade" }),
    createdAt: timestamp("created_at").notNull().defaultNow(),
  },
  (t) => [
    unique("task_assignees_task_user_unique").on(t.taskId, t.assigneeId),
    // Drives the per-user "tasks assigned to me" feed.
    index("idx_assignee_user").on(t.assigneeId),
  ],
);

/** Per-project label catalog. color is an opaque CSS token (e.g. #ff0000). */
export const labels = mysqlTable(
  "labels",
  {
    id: varchar("id", { length: 36 }).primaryKey(),
    projectId: varchar("project_id", { length: 36 })
      .notNull()
      .references(() => projects.id, { onDelete: "cascade" }),
    name: text("name").notNull(),
    color: varchar("color", { length: 32 }).notNull().default("#94a3b8"),
    createdAt: timestamp("created_at").notNull().defaultNow(),
  },
  (t) => [index("idx_label_project").on(t.projectId)],
);

/** task <-> label join. The composite unique keeps a label on a task once. */
export const taskLabels = mysqlTable(
  "task_labels",
  {
    id: varchar("id", { length: 36 }).primaryKey(),
    taskId: varchar("task_id", { length: 36 })
      .notNull()
      .references(() => tasks.id, { onDelete: "cascade" }),
    labelId: varchar("label_id", { length: 36 })
      .notNull()
      .references(() => labels.id, { onDelete: "cascade" }),
  },
  (t) => [
    unique("task_labels_task_label_unique").on(t.taskId, t.labelId),
    index("idx_task_label_label").on(t.labelId),
  ],
);

/** Comment thread per task. author is a Better Auth user referenced by id. */
export const taskComments = mysqlTable(
  "task_comments",
  {
    id: varchar("id", { length: 36 }).primaryKey(),
    taskId: varchar("task_id", { length: 36 })
      .notNull()
      .references(() => tasks.id, { onDelete: "cascade" }),
    authorId: varchar("author_id", { length: 255 })
      .notNull()
      .references(() => user.id, { onDelete: "cascade" }),
    body: text("body").notNull(),
    createdAt: timestamp("created_at").notNull().defaultNow(),
  },
  (t) => [
    // Drives the per-task comment feed (most-recent-first).
    index("idx_comment_task_time").on(t.taskId, t.createdAt),
  ],
);

export const projectsRelations = relations(projects, ({ one, many }) => ({
  owner: one(user, { fields: [projects.ownerId], references: [user.id] }),
  tasks: many(tasks),
  labels: many(labels),
}));

export const tasksRelations = relations(tasks, ({ one, many }) => ({
  project: one(projects, {
    fields: [tasks.projectId],
    references: [projects.id],
  }),
  assignees: many(taskAssignees),
  labels: many(taskLabels),
  comments: many(taskComments),
}));

export const taskAssigneesRelations = relations(taskAssignees, ({ one }) => ({
  task: one(tasks, {
    fields: [taskAssignees.taskId],
    references: [tasks.id],
  }),
  assignee: one(user, {
    fields: [taskAssignees.assigneeId],
    references: [user.id],
  }),
}));

export const labelsRelations = relations(labels, ({ one, many }) => ({
  project: one(projects, {
    fields: [labels.projectId],
    references: [projects.id],
  }),
  tasks: many(taskLabels),
}));

export const taskLabelsRelations = relations(taskLabels, ({ one }) => ({
  task: one(tasks, {
    fields: [taskLabels.taskId],
    references: [tasks.id],
  }),
  label: one(labels, {
    fields: [taskLabels.labelId],
    references: [labels.id],
  }),
}));

export const taskCommentsRelations = relations(taskComments, ({ one }) => ({
  task: one(tasks, {
    fields: [taskComments.taskId],
    references: [tasks.id],
  }),
  author: one(user, {
    fields: [taskComments.authorId],
    references: [user.id],
  }),
}));

import { drizzle } from "drizzle-orm/mysql2";
import mysql from "mysql2/promise";

// Serverless: a small pool per short-lived instance — many instances × a big pool exhausts MySQL.
export const pool = mysql.createPool({ uri: process.env.DATABASE_URL!, connectionLimit: 2 });
export const db = drizzle({ client: pool });

import { drizzle } from "drizzle-orm/mysql2";
import mysql from "mysql2/promise";

// Long-running process: a real, reused pool (mysql2 manages idle recycling).
export const pool = mysql.createPool({ uri: process.env.DATABASE_URL!, connectionLimit: 10 });
export const db = drizzle({ client: pool });

import { drizzle } from "drizzle-orm/planetscale-serverless";
import { Client } from "@planetscale/database";

// Edge/Workers have NO TCP sockets, so mysql2 cannot run here. PlanetScale's HTTP driver
// speaks MySQL over fetch — the client that works on Workers (the MySQL analog of Neon's HTTP driver).
const client = new Client({ url: process.env.DATABASE_URL! });
export const db = drizzle({ client });