import { Command } from "https://deno.land/x/cliffy@v0.25.7/command/mod.ts";
import { DB } from "https://deno.land/x/sqlite/mod.ts";
import {join} from "https://deno.land/std@0.178.0/path/mod.ts";

// for the demo, we will place the state in the /tmp instead of $HOME
const HOME_DIRECTORY = '/tmp';
const CLI_STATE_DIRECTORY = join(HOME_DIRECTORY, 'deno-cli-example');

// the CLI will need read and write access to /tmp/deno-cli-example directory
await Deno.mkdir(CLI_STATE_DIRECTORY, {recursive: true});
const MAIN_DB_FILE = join(CLI_STATE_DIRECTORY, 'state.sqlite');


/**
 * Create tables in the database.  This function is a
 * trivial data migration algorithm.
 */
function initDB(){
  const db = new DB(MAIN_DB_FILE);
  const init_db = `
  CREATE TABLE IF NOT EXISTS usernames (
      id INTEGER PRIMARY KEY AUTOINCREMENT,
      username TEXT,
      creation_ts DATETIME DEFAULT CURRENT_TIMESTAMP
  )
  `;
  try {
    db.execute(init_db);
  } finally {
    db.close();
  }
}

/**
 * Returns the latest username saved in the state.
 */
function getUsernameFromDB(){
  const db = new DB(MAIN_DB_FILE);
  try {
    return db.query(`SELECT username 
                     FROM usernames 
                     ORDER BY creation_ts 
                     DESC LIMIT 1`)[0]
  } finally {
    db.close();
  }
}

/**
 * Set the passed username in the database.
 */
function setUsernameInDB(username: string){
  const db = new DB(MAIN_DB_FILE);
  try {
    return db.query("INSERT INTO usernames (username) VALUES (?)", [username])
  } finally {
    db.close();
  }
}

function getUsernameOrDefault(name?: string): string{
  return name || getUsernameFromDB() || 'no username set yet.';
}

/**
 * Calls httpbin.org/get with the username as argument.
 */
async function getFromService(options){
  const username = getUsernameOrDefault(options.usermame);
  const encodedUsername = encodeURIComponent(username);
  const url = `https://httpbin.org/get?username=${encodedUsername}`;
  const response = await fetch();
  console.log(await response.json());
}

async function setProperties(options){
  if(options.username){
    setUsernameInDB(options.username);
  }
}

initDB();
await new Command()
  .name("deno-cli-example")
  .version("0.1.0")
  .description("Example of a deno CLI.")
  .command('call-service')
  .description('Example of a real use case. call-service will called '
                + 'https://httpbin.org/get with username passed as parameter.')
  .option("--username <username>", 
          'username to use in the service call. If no username specified, the '
           + ' persisted username  will be used.')
  .action(getFromService)
  .command('set-properties')
  .description('Persist properties to state. Persisted properties will then '
                + 'be used as default in other commands')
  .option("--username <username>", "Set the default username property.", 
          {required: true})
  .action(setProperties)
  .parse(Deno.args);