update

#!/usr/bin/env node

var path = require('path');

var basePath = process.argv[1].split(path.sep),
    self = basePath.pop(),
    stats = { rows: 0, updates: 0 },
    updates = {
      docs: []
    },
    index = {},
    data;

var usageInfo = `
Usage:

  cat updates.json | ${self} index.json

Description:

Examples:

  Update the \`parent\` property on a set of docs, where \`parent\` is an
  embedded doc.

    Data to update provided by client:

      $ cat updates.csv
      uuid,parent
      0ee7d41b,74a7f78e

    Index generated with \`jq\` and \`_all_docs\` view:

      $ cat index.json
      [
        {
          "_id": "0ee7d41b",
          ...
        },
        {
          "_id": "74a7f78e",
          ...
        },
      ]

    cat updates.csv | medic-csv-to-json | ${self} index.json > updates.json
    curl -H 'content-type:application/json' \\
         -d@updates.json $COUCH_URL/medic/_bulk_docs

`;

var usage = function() {
  console.error(usageInfo);
  process.exit(1);
};

if (process.argv.length < 3) {
  console.error('\nError: Please provide the file system path to the index.');
  usage();
} else {
  // create index
  var tmp = require(path.resolve(process.argv[2]));
  if (Array.isArray(tmp)) {
    tmp.forEach(function(obj) {
      try {
        index[obj._id] = obj;
      } catch(e) {
        console.error(obj);
        throw e;
      }
    });
  }
}

var prop = function(obj, path, value) {
  if (typeof path == 'string') {
    return prop(obj, path.split('.'), value);
  } else if (path.length == 1 && typeof value !== 'undefined') {
    return obj[path[0]] = value;
  } else if (path.length == 0) {
    return obj;
  } else {
    return prop(obj[path[0]], path.slice(1), value);
  }
};

/*
 * Special property `uuid` used as identifier for doc that is being updated.
 */
var onRow = function(row) {
  stats.rows++;
  var doc = index[row.uuid];
  if (!doc) {
    throw new Error(`Index missing uuid ${row.uuid}.`);
  }
  Object.keys(row).forEach(function(k) {
    // support dot notation
    var obj = prop(doc, k);
    if (!obj) {
      // if no properties match on doc then skip
      return;
    }
    if (typeof index[row[k]] !== 'undefined') {
      // the key value is in the doc index
      prop(doc, k, index[row[k]]);
      updates.docs.push(doc);
      stats.updates++;
    } else {
      // simple property update
      prop(doc, k, row[k]);
      updates.docs.push(doc);
      stats.updates++;
    }
  });
};


process.stdin.setEncoding('utf8');

var input = '';
process.stdin.on('data', function (chunk) {
  input += chunk;
});

process.stdin.on('end', function () {
  data = JSON.parse(input);
  data.forEach(onRow);
  process.stdout.write(JSON.stringify(updates));
  console.error(stats);
});