import {
  Pool,
  PoolClient,
  PostgresError,
} from "https://deno.land/x/postgres@v0.16.1/mod.ts";
import {
  type QueryArguments,
  type QueryArrayResult,
  type QueryObjectResult,
} from "https://deno.land/x/postgres@v0.16.1/query/query.ts?s=QueryArguments";
import { config } from "@/config.ts";

import {
  type Identifiable,
  type Note,
  type Timestamped,
  type User,
} from "@/types.ts";

export { PostgresError };
export { type QueryObjectResult };

const pool = new Pool(config.postgres.url, 3, true);

async function dbOp<T>(op: (connection: PoolClient) => Promise<T>) {
  let result = null;
  let exception = null;
  try {
    const connection = await pool.connect();
    try {
      result = await op(connection);
    } catch (err) {
      console.error("Error querying database:", { ...err });
      exception = err;
    } finally {
      connection.release();
    }
  } catch (err) {
    exception = err;
    console.error("Error connecting to database:", err);
  }
  if (exception != null) throw exception;
  return result;
}

export async function queryObject<T>(
  sql: string,
  args?: QueryArguments,
): Promise<QueryObjectResult<T> | null> {
  return await dbOp(async (connection) =>
    await connection.queryObject<T>({
      camelcase: true,
      text: sql.trim(),
      args,
    })
  );
}

export async function queryArray<T extends []>(
  sql: string,
  args?: QueryArguments,
): Promise<QueryArrayResult<T> | null> {
  return await dbOp(async (connection) =>
    await connection.queryArray<T>({
      text: sql.trim(),
      args,
    })
  );
}

export async function listNotes() {
  return await queryObject<Note>(
    "select * from note order by created_at desc",
  );
}

export async function getNote(id: string | { id: string }) {
  const idVal = typeof id == "object" ? id.id : id;
  console.debug("getNote id =", JSON.stringify(idVal));
  return await queryObject<Note>(
    "select * from note where id = $1",
    [idVal],
  );
}

type Ungenerated<T> = Omit<T, keyof Identifiable | keyof Timestamped>;

export async function createNote({ content }: Ungenerated<Note>) {
  return await queryObject<Note>(
    "insert into note (content) values ($1) returning *",
    [content],
  );
}

export async function createUser(
  { username, passwordDigest }: Ungenerated<User>,
) {
  return await queryObject<{ user_id: string }>(
    `
    with new_user as (
      insert into "user" (username, password_digest, status)
        values ($username, $passwordDigest, 'unverified')
        returning id as user_id
    ), new_team as (
      insert into "team" (display_name)
        values ($teamName)
        returning id as team_id
    )
    insert into "team_user" (user_id, team_id, status)
      values (
        (select user_id from new_user),
        (select team_id from new_team),
        'owner'
      ) returning user_id
    `,
    { username, passwordDigest, teamName: `${username}'s First Team` },
  );
}

export async function getUser({ id, username }: Partial<User>) {
  if (!id && !username) throw "getUser called without id or username";
  const column = id ? "id" : "username";
  return await queryObject<User>(
    `select * from "user" where "${column}" = $1`,
    [id || username],
  );
}