/**
 * DalalAI — Google Sheets connector
 * =================================
 * Pull live DalalAI analytics straight into Google Sheets with a custom
 * =DALALAI() formula, backed by the DalalAI Developer API.
 *
 * SETUP (one time):
 *   1. In your Google Sheet: Extensions ▸ Apps Script
 *   2. Delete any boilerplate, paste this whole file, click Save.
 *   3. Reload the sheet. A new "DalalAI" menu appears.
 *   4. DalalAI ▸ Set API key — paste the key from
 *      https://dalalai.com  ▸  Developer API  ▸  Generate Key.
 *      (The key is stored in private Script Properties, never in a cell.)
 *
 * USAGE (in any cell):
 *   =DALALAI("convergence")                       → full convergence table
 *   =DALALAI("convergence-scores", "RELIANCE")    → one symbol
 *   =DALALAI("predictions", , "Symbol,Score")     → only chosen columns
 *   =DALALAI("convergence", , , 25)               → cap to 25 rows
 *
 * Data auto-refreshes whenever the sheet recalculates. To force a refresh,
 * use DalalAI ▸ Refresh now (re-runs all DALALAI formulas).
 *
 * Endpoints: any /api/v1/{endpoint} listed at https://dalalai.com/api-docs
 * (e.g. convergence, convergence-scores, predictions, smart-money,
 *  regime, sectors, valuation). Free tier = 1,000 calls/month.
 */

var DALALAI_BASE = 'https://dalalai.com/api/v1/';
var DALALAI_KEY_PROP = 'DALALAI_API_KEY';

/**
 * Custom function: fetch a DalalAI endpoint as a table.
 *
 * @param {string} endpoint  API endpoint name, e.g. "convergence".
 * @param {string=} symbol   Optional ticker filter, e.g. "RELIANCE".
 * @param {string=} fields   Optional comma-separated columns to keep.
 * @param {number=} limit    Optional max number of rows.
 * @return {Array<Array<string>>} 2-D range (header row + data rows).
 * @customfunction
 */
function DALALAI(endpoint, symbol, fields, limit) {
  if (!endpoint) { throw new Error('DALALAI: first argument (endpoint) is required, e.g. "convergence".'); }
  var key = _dalalaiKey_();
  if (!key) { throw new Error('DALALAI: no API key set. Use the DalalAI ▸ Set API key menu.'); }

  var url = DALALAI_BASE + encodeURIComponent(String(endpoint).trim()) + '?format=csv';
  if (symbol) { url += '&symbol=' + encodeURIComponent(String(symbol).trim()); }
  if (fields) { url += '&fields=' + encodeURIComponent(String(fields).replace(/\s+/g, '')); }
  if (limit)  { url += '&limit='  + encodeURIComponent(String(parseInt(limit, 10) || '')); }

  var resp = UrlFetchApp.fetch(url, {
    method: 'get',
    muteHttpExceptions: true,
    headers: { 'X-API-Key': key, 'Accept': 'text/csv' }
  });

  var code = resp.getResponseCode();
  var text = resp.getContentText();
  if (code === 401 || code === 403) { throw new Error('DALALAI: API key rejected (HTTP ' + code + '). Re-set the key via the DalalAI menu.'); }
  if (code === 429) { throw new Error('DALALAI: rate limit / quota exceeded (HTTP 429). Upgrade tier or retry later.'); }
  if (code >= 400)  { throw new Error('DALALAI: request failed (HTTP ' + code + '). Check the endpoint name.'); }

  var rows = _dalalaiParseCsv_(text);
  if (!rows.length) { return [['No data returned for "' + endpoint + '".']]; }
  return rows;
}

/** Menu bootstrap. */
function onOpen() {
  SpreadsheetApp.getUi()
    .createMenu('DalalAI')
    .addItem('Set API key', 'dalalaiSetKey')
    .addItem('Refresh now', 'dalalaiRefresh')
    .addSeparator()
    .addItem('Test connection', 'dalalaiTest')
    .addToUi();
}

/** Prompt for and store the API key in private Script Properties. */
function dalalaiSetKey() {
  var ui = SpreadsheetApp.getUi();
  var res = ui.prompt('DalalAI API key', 'Paste your DalalAI Developer API key:', ui.ButtonSet.OK_CANCEL);
  if (res.getSelectedButton() !== ui.Button.OK) { return; }
  var key = (res.getResponseText() || '').trim();
  if (!key) { ui.alert('No key entered.'); return; }
  PropertiesService.getScriptProperties().setProperty(DALALAI_KEY_PROP, key);
  ui.alert('DalalAI API key saved. Try =DALALAI("convergence") in a cell.');
}

/** Force every DALALAI() formula to recalculate. */
function dalalaiRefresh() {
  SpreadsheetApp.flush();
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  // Toggle an unused named-value to bust the custom-function cache.
  var p = PropertiesService.getScriptProperties();
  p.setProperty('DALALAI_NONCE', String(Date.now()));
  ss.toast('DalalAI formulas refreshed.', 'DalalAI', 3);
}

/** Quick connectivity check. */
function dalalaiTest() {
  var ui = SpreadsheetApp.getUi();
  try {
    var rows = DALALAI('regime');
    ui.alert('Connected ✓  Received ' + rows.length + ' row(s).');
  } catch (e) {
    ui.alert('Connection failed: ' + e.message);
  }
}

/** @return {string} stored API key or empty string. */
function _dalalaiKey_() {
  return PropertiesService.getScriptProperties().getProperty(DALALAI_KEY_PROP) || '';
}

/**
 * Minimal RFC-4180 CSV parser (handles quoted fields, commas, newlines).
 * @param {string} text  CSV text.
 * @return {Array<Array<string>>}
 */
function _dalalaiParseCsv_(text) {
  var out = [];
  if (!text) { return out; }
  var row = [];
  var field = '';
  var inQuotes = false;
  for (var i = 0; i < text.length; i++) {
    var ch = text[i];
    if (inQuotes) {
      if (ch === '"') {
        if (text[i + 1] === '"') { field += '"'; i++; }
        else { inQuotes = false; }
      } else { field += ch; }
    } else if (ch === '"') {
      inQuotes = true;
    } else if (ch === ',') {
      row.push(_dalalaiCoerce_(field)); field = '';
    } else if (ch === '\n') {
      row.push(_dalalaiCoerce_(field)); field = '';
      out.push(row); row = [];
    } else if (ch === '\r') {
      // ignore; \n handles row break
    } else {
      field += ch;
    }
  }
  if (field.length || row.length) { row.push(_dalalaiCoerce_(field)); out.push(row); }
  return out;
}

/** Convert numeric-looking strings to numbers so Sheets can chart/sum them. */
function _dalalaiCoerce_(v) {
  if (v === '' || v == null) { return ''; }
  var n = Number(v);
  return (!isNaN(n) && /^-?\d*\.?\d+$/.test(v)) ? n : v;
}