(async function() {

/*

"init" => what it sounds like, basic setup things
"tumblr" => ok, we have oauth2 creds, now let's authorize with the user!
"ready" => alright! main thing!!

*/
let {system_state, tumblr_expiry_date} = await chrome.storage.local.get({"system_state": "init", "tumblr_expiry_date": 0});

let refreshTimeout = (system_state == "ready") ? setTimeout(refreshToken, Date.now() - tumblr_expiry_date) : null;

async function refreshToken() {
  const { tumblr_refresh_token, oauth_consumer_key, oauth_secret_key } = await chrome.storage.local.get(["tumblr_refresh_token", "oauth_consumer_key", "oauth_secret_key"]);

  const form = new FormData();
  form.append("grant_type", "refresh_token");
  form.append("refresh_token", tumblr_refresh_token);
  form.append("client_id", oauth_consumer_key);
  form.append("client_secret", oauth_secret_key);
  const {expires_in, access_token, refresh_token} = await fetch("https://api.tumblr.com/v2/oauth2/token", {body: form, method: "POST"}).then(a => a.json());
  const tumblr_expiry_date = expires_in * 1000 + Date.now();

  await chrome.storage.local.set({tumblr_expiry_date, tumblr_access_token: access_token, tumblr_refresh_token: refresh_token});

  refreshTimeout = setTimeout(refreshToken, expires_in * 1000);

}

async function doNextThing(startup) {
  switch (system_state) {
    case "init":
      await chrome.tabs.create({url: "chrome-extension://"+chrome.runtime.id+"/init.html"});
      break;
    case "tumblr":
      let {oauth_consumer_key} = await chrome.storage.local.get(["oauth_consumer_key"]);
      await chrome.tabs.create({url: "https://tumblr.com/oauth2/authorize?response_type=code&scope=basic%20offline_access%20write&state=NA&client_id="+oauth_consumer_key});
  }
}

chrome.runtime.onMessage.addListener(async function({id, type, payload}, sender) {
  console.debug(`Got message "${type}"@"${id}", payload ${JSON.stringify(payload)}`);
  switch (type) {
  case "set_creds":
    const {oauth_consumer_key, oauth_secret_key} = payload;
    clearTimeout(refreshTimeout);
    system_state = "tumblr";
    await chrome.storage.local.set({system_state, oauth_consumer_key, oauth_secret_key});

    doNextThing();

    if (sender.tab) {
      await chrome.tabs.sendMessage(sender.tab.id, {id, status: "OK"});
    }
    return;
  default:
    if (sender.tab) {
      chrome.tabs.sendMessage(sender.tab.id, {id, status: "ERRUNDEF", message: "No message type `"+type+"`!"});
    }
    return;
  }
});

chrome.tabs.onUpdated.addListener(async function(tabId, {url}, tab) {
  if (system_state == "tumblr" && url?.startsWith("https://example.com/tfm_redirect")) {
    const { oauth_consumer_key, oauth_secret_key } = await chrome.storage.local.get(["oauth_consumer_key", "oauth_secret_key"]);

    const code = /code=([a-fA-F0-9]+)/.exec(url)[1];

    const form = new FormData();
    form.append("grant_type", "authorization_code");
    form.append("code", code);
    form.append("client_id", oauth_consumer_key);
    form.append("client_secret", oauth_secret_key);
    const {expires_in, access_token, refresh_token} = await fetch("https://api.tumblr.com/v2/oauth2/token", {body: form, method: "POST"}).then(a => a.json());

    const tumblr_expiry_date = expires_in * 1000 + Date.now();
    await chrome.storage.local.set({system_state: "ready", tumblr_expiry_date, tumblr_access_token: access_token, tumblr_refresh_token: refresh_token});
    clearTimeout(refreshTimeout);
    refreshTimeout = setTimeout(refreshToken, expires_in * 1000);

    await chrome.tabs.update(tabId, {url: "chrome-extension://"+chrome.runtime.id+"/ui.html"});
  }
});

doNextThing(true);

})();