// Documentation: https://adssystem.store/scripts/impression-share-loss-report/
// Writes: Nothing. Read-only.

// Impression share loss report
// Separates the two reasons a campaign is not showing: budget and ad rank.
// They need opposite responses, and the account summary does not distinguish them.
// Read-only.

var DAYS      = 7;
var MIN_COST  = 20;    // ignore campaigns too small to act on
var BUDGET_AT = 0.10;  // flag when 10% or more of impression share is lost to budget
var RANK_AT   = 0.40;  // flag when 40% or more is lost to rank
var EMAIL     = '';

function main() {
  var rows = AdsApp.search(
    'SELECT campaign.name, campaign.advertising_channel_type, ' +
    '       metrics.cost_micros, metrics.conversions, ' +
    '       metrics.search_impression_share, ' +
    '       metrics.search_budget_lost_impression_share, ' +
    '       metrics.search_rank_lost_impression_share ' +
    'FROM campaign ' +
    'WHERE segments.date DURING LAST_' + DAYS + '_DAYS ' +
    '  AND campaign.status = "ENABLED"'
  );

  var budgetBound = [];
  var rankBound   = [];

  while (rows.hasNext()) {
    var r    = rows.next();
    var cost = Number(r.metrics.costMicros) / 1000000;
    if (cost < MIN_COST) { continue; }

    var is       = num(r.metrics.searchImpressionShare);
    var lostBud  = num(r.metrics.searchBudgetLostImpressionShare);
    var lostRank = num(r.metrics.searchRankLostImpressionShare);

    // Impression share metrics are not reported for every channel type.
    if (is === null && lostBud === null && lostRank === null) { continue; }

    var row = {
      name: String(r.campaign.name),
      type: String(r.campaign.advertisingChannelType),
      cost: cost,
      conv: Number(r.metrics.conversions),
      is:   is,
      bud:  lostBud,
      rank: lostRank
    };

    if (lostBud !== null && lostBud >= BUDGET_AT)  { budgetBound.push(row); }
    if (lostRank !== null && lostRank >= RANK_AT)  { rankBound.push(row); }
  }

  if (!budgetBound.length && !rankBound.length) {
    Logger.log('No campaign over the thresholds in the last ' + DAYS + ' days.');
    return;
  }

  budgetBound.sort(function (a, b) { return b.cost - a.cost; });
  rankBound.sort(function (a, b) { return b.cost - a.cost; });

  var lines = [AdsApp.currentAccount().getName(), 'Last ' + DAYS + ' days', ''];

  if (budgetBound.length) {
    lines.push('LOSING SHARE TO BUDGET  (raise the budget, or accept the ceiling)');
    lines.push('campaign\ttype\tcost\tconv\tIS\tlost to budget');
    for (var i = 0; i < budgetBound.length; i++) { lines.push(fmt(budgetBound[i], 'bud')); }
    lines.push('');
  }

  if (rankBound.length) {
    lines.push('LOSING SHARE TO RANK  (relevance, bids or landing page, not budget)');
    lines.push('campaign\ttype\tcost\tconv\tIS\tlost to rank');
    for (var j = 0; j < rankBound.length; j++) { lines.push(fmt(rankBound[j], 'rank')); }
  }

  var body = lines.join('\n') +
    '\n\nShares above 90% are reported as 0.9 and below 10% as 0.1. ' +
    'Impression share is not reported for every campaign type.';

  Logger.log(body);
  if (EMAIL) {
    MailApp.sendEmail(EMAIL, 'Impression share loss - ' + AdsApp.currentAccount().getName(), body);
  }
}

function fmt(r, which) {
  return [
    r.name,
    r.type,
    r.cost.toFixed(2),
    r.conv.toFixed(1),
    pct(r.is),
    pct(r[which])
  ].join('\t');
}

function num(v) {
  if (v === null || v === undefined || v === '') { return null; }
  var n = Number(v);
  return isNaN(n) ? null : n;
}

function pct(v) {
  return v === null ? '-' : (v * 100).toFixed(0) + '%';
}