// =============================================================
//  DANKCHARTS.FM — Google Sheet Sync Script
// =============================================================
//  SETUP (do this once):
//  1. Fill in your details in the "Settings" tab:
//       B1 = Your Last.fm username
//       B2 = Your Last.fm API key  (free: last.fm/api/account/create)
//       B3 = Data tab name         (default: Full Raw Listening History)
//
//  2. FOR AUTO-SYNC: click the button next to "Help" in the Google Sheets
//     menu bar called "Last.fm" → select "Start Auto-Update (90 min)"
//     It will sync new plays every 90 minutes.
//
//  3. FOR MANUAL ENTRY: Deploy this script as a Web App
//     (Deploy → New deployment → Web app → Execute as: Me → Access: Anyone)
//     then paste the generated URL into the dankcharts.fm settings.
//
//  NOTE — "This app isn't verified" warning:
//  Google shows this screen the first time you authorize the script.
//  It is normal for personal scripts. Click Advanced →
//  "Go to [app name] (unsafe)" → Allow. It is safe because you
//  own this script and it only accesses your own Google Sheet.
// =============================================================


// Reads your credentials from the Settings tab.
// No need to edit this function.
function getSettings_() {
  var s = SpreadsheetApp.getActiveSpreadsheet().getSheetByName('Settings');
  if (!s) throw new Error('"Settings" tab not found. Check your sheet setup.');
  return {
    user:    s.getRange('B1').getValue().toString().trim(),
    apiKey:  s.getRange('B2').getValue().toString().trim(),
    tabName: s.getRange('B3').getValue().toString().trim() || 'Full Raw Listening History'
  };
}


// =============================================================
//  AUTO-SYNC
//  Fetches any new plays from Last.fm and appends them to your
//  data tab. Runs every 90 minutes once you click
//  Last.fm → Start Auto-Update in the sheet menu.
// =============================================================
function fetchAndLogLastFmHistory() {
  var cfg = getSettings_();

  // Stop if credentials are missing
  if (!cfg.user || !cfg.apiKey) {
    Logger.log('ERROR: Fill in your Last.fm Username (B1) and API Key (B2) in the Settings tab.');
    return;
  }

  // Remove any existing triggers to avoid duplicates (Google limits you to 20)
  ScriptApp.getProjectTriggers().forEach(function(t) {
    if (t.getHandlerFunction() === 'fetchAndLogLastFmHistory') ScriptApp.deleteTrigger(t);
  });

  var ss    = SpreadsheetApp.getActiveSpreadsheet();
  var sheet = ss.getSheetByName(cfg.tabName);
  if (!sheet) {
    Logger.log('ERROR: Tab "' + cfg.tabName + '" not found. Check B3 in the Settings tab.');
    return;
  }

  // Use the sheet's own timezone so dates are stored in your local time
  var tz = ss.getSpreadsheetTimeZone();

  // Find the last recorded track so we only fetch plays newer than that
  var maxRow = sheet.getLastRow(), lastTs = 0, actualLastRow = 0;
  if (maxRow > 1) {
    var vals = sheet.getRange(1, 4, maxRow, 1).getValues(); // column D = date
    for (var i = vals.length - 1; i >= 0; i--) {
      var v = vals[i][0];
      if (v && v !== '') {
        actualLastRow = i + 1;
        var str = v instanceof Date ? Utilities.formatDate(v, tz, 'yyyy-MM-dd HH:mm:ss') : String(v);
        if (/\d{4}-\d{2}-\d{2} \d{2}:\d{2}:\d{2}/.test(str))
          lastTs = Math.floor(Utilities.parseDate(str, tz, 'yyyy-MM-dd HH:mm:ss').getTime() / 1000);
        break;
      }
    }
  }

  // Build the Last.fm API request (fetches up to 200 new plays at a time)
  var url = 'https://ws.audioscrobbler.com/2.0/?method=user.getrecenttracks'
    + '&user=' + encodeURIComponent(cfg.user) + '&api_key=' + cfg.apiKey
    + '&format=json&from=' + (lastTs + 1) + '&limit=200';

  // Fetch with up to 5 retries in case of rate limiting or network errors
  var response, attempt = 0;
  while (attempt < 5) {
    try {
      response = UrlFetchApp.fetch(url, { muteHttpExceptions: true,
        headers: { 'Cache-Control': 'no-cache', 'Pragma': 'no-cache' } });
      if (response.getResponseCode() === 429 || response.getResponseCode() === 403)
        throw new Error('Rate limited');
      break;
    } catch(e) {
      if (++attempt >= 5) {
        // Give up for now, try again in 90 minutes
        ScriptApp.newTrigger('fetchAndLogLastFmHistory').timeBased().after(90*60*1000).create();
        return;
      }
      Utilities.sleep(Math.pow(2, attempt) * 1000 + Math.floor(Math.random() * 1000));
    }
  }

  var data = JSON.parse(response.getContentText());
  if (data.error) {
    Logger.log('Last.fm API error: ' + data.message);
    ScriptApp.newTrigger('fetchAndLogLastFmHistory').timeBased().after(90*60*1000).create();
    return;
  }

  // Write new tracks to the sheet (skip the "now playing" entry which has no timestamp)
  var tracks = data.recenttracks && data.recenttracks.track;
  if (tracks && tracks.length) {
    var done = tracks.filter(function(t) { return t.date && t.date.uts; });
    if (done.length) {
      done.sort(function(a, b) { return +a.date.uts - +b.date.uts; }); // oldest first
      var rows = done.map(function(t) {
        return [
          t.name,
          t.artist['#text'],
          t.album['#text'],
          Utilities.formatDate(new Date(+t.date.uts * 1000), tz, 'yyyy-MM-dd HH:mm:ss')
        ];
      });
      sheet.getRange(actualLastRow + 1, 1, rows.length, 4).setValues(rows);
      Logger.log('Added ' + rows.length + ' new track(s).');
    }
  } else {
    Logger.log('No new tracks since last sync.');
  }

  // Schedule the next sync in 90 minutes
  ScriptApp.newTrigger('fetchAndLogLastFmHistory').timeBased().after(90*60*1000).create();
}


// Run this once from Last.fm → Start Auto-Update to kick off the 90-minute cycle.
function setupTrigger() {
  ScriptApp.getProjectTriggers().forEach(function(t) {
    if (t.getHandlerFunction() === 'fetchAndLogLastFmHistory') ScriptApp.deleteTrigger(t);
  });
  ScriptApp.newTrigger('fetchAndLogLastFmHistory').timeBased().after(60*1000).create();
  Logger.log('All set! First sync in 1 minute, then every 90 minutes automatically.');
}


// Adds the "Last.fm" menu to your sheet when you open it.
function onOpen() {
  SpreadsheetApp.getUi().createMenu('Last.fm')
    .addItem('Fetch Latest Tracks', 'fetchAndLogLastFmHistory')
    .addItem('Start Auto-Update (90 min)', 'setupTrigger')
    .addToUi();
}


// =============================================================
//  MANUAL ENTRY (Web App)
//  This function receives a play from dankcharts.fm and writes
//  it to your sheet. Only needed if you want the "Add Play"
//  button — requires deploying this script as a Web App.
// =============================================================
function doPost(e) {
  try {
    var data    = JSON.parse(e.postData.contents);
    var ss      = SpreadsheetApp.getActiveSpreadsheet();
    var cfg     = ss.getSheetByName('Settings');
    var tabName = cfg ? cfg.getRange('B3').getValue().toString().trim() : '';
    var sheet   = ss.getSheetByName(tabName || 'Full Raw Listening History') || ss.getSheets()[0];

    // Detect which column is which by reading the header row
    var lastCol = Math.max(sheet.getLastColumn(), 1);
    var headers = sheet.getRange(1, 1, 1, lastCol).getValues()[0]
      .map(function(h) { return h.toString().toLowerCase().trim(); });
    var aliases = {
      title:    ['song title', 'title', 'track', 'track name', 'song name'],
      artist:   ['artist', 'artist name', 'performer'],
      album:    ['album', 'album name', 'release'],
      datetime: ['date and time', 'date', 'datetime', 'timestamp', 'time', 'played at', 'scrobble time']
    };
    var colIdx = {};
    for (var key in aliases) {
      for (var i = 0; i < aliases[key].length; i++) {
        var idx = headers.indexOf(aliases[key][i]);
        if (idx !== -1) { colIdx[key] = idx; break; }
      }
    }

    var tz = ss.getSpreadsheetTimeZone();

    // Edit an existing row by matching its original timestamp
    if (data.action === 'update') {
      var origFmt = Utilities.formatDate(new Date(data.originalTimestamp * 1000), tz, 'yyyy-MM-dd HH:mm:ss');
      var newFmt  = Utilities.formatDate(new Date(data.timestamp * 1000), tz, 'yyyy-MM-dd HH:mm:ss');
      var lastRow = sheet.getLastRow();
      if (lastRow < 2) throw new Error('Sheet is empty');
      var values = sheet.getRange(2, 1, lastRow - 1, lastCol).getValues();
      for (var r = 0; r < values.length; r++) {
        var cell = values[r][colIdx.datetime];
        var cellStr = cell instanceof Date
          ? Utilities.formatDate(cell, tz, 'yyyy-MM-dd HH:mm:ss')
          : cell.toString().trim().slice(0, 19);
        if (cellStr === origFmt) {
          if (colIdx.title    !== undefined) sheet.getRange(r + 2, colIdx.title    + 1).setValue(data.track  || '');
          if (colIdx.artist   !== undefined) sheet.getRange(r + 2, colIdx.artist   + 1).setValue(data.artist || '');
          if (colIdx.album    !== undefined) sheet.getRange(r + 2, colIdx.album    + 1).setValue(data.album  || '');
          if (colIdx.datetime !== undefined) sheet.getRange(r + 2, colIdx.datetime + 1).setValue(newFmt);
          return ContentService.createTextOutput(JSON.stringify({ status: 'ok', updated: true }))
            .setMimeType(ContentService.MimeType.JSON);
        }
      }
      throw new Error('Row not found for timestamp: ' + origFmt);
    }

    // Add a new row
    var fmt = Utilities.formatDate(new Date(data.timestamp * 1000), tz, 'yyyy-MM-dd HH:mm:ss');
    var row = new Array(lastCol).fill('');
    if (colIdx.title    !== undefined) row[colIdx.title]    = data.track  || '';
    if (colIdx.artist   !== undefined) row[colIdx.artist]   = data.artist || '';
    if (colIdx.album    !== undefined) row[colIdx.album]    = data.album  || '';
    if (colIdx.datetime !== undefined) row[colIdx.datetime] = fmt;
    sheet.appendRow(row);

    return ContentService.createTextOutput(JSON.stringify({ status: 'ok' }))
      .setMimeType(ContentService.MimeType.JSON);
  } catch(err) {
    return ContentService.createTextOutput(JSON.stringify({ status: 'error', message: err.message }))
      .setMimeType(ContentService.MimeType.JSON);
  }
}