import _ from "lodash";

function renderTagCondition(tag, index) {
  var str = "";
  var operator = tag.operator;
  var value = tag.value;
  if (index > 0) {
    str = (tag.condition || "AND") + " ";
  }

  if (!operator) {
    if (/^\/.*\/$/.test(tag.value)) {
      operator = "=~";
    } else {
      operator = "=";
    }
  }

  // quote value unless regex or number
  if (operator !== "=~" && operator !== "!~" && isNaN(+value)) {
    value = "'" + value + "'";
  }

  return str + '"' + tag.key + '" ' + operator + " " + value;
}

export class InfluxQueryBuilder {
  constructor(private target, private database?) {}

  buildExploreQuery(
    type: string,
    withKey?: string,
    withMeasurementFilter?: string
  ) {
    var query;
    var measurement;
    var policy;

    if (type === "TAG_KEYS") {
      query = "SHOW TAG KEYS";
      measurement = this.target.measurement;
      policy = this.target.policy;
    } else if (type === "TAG_VALUES") {
      query = "SHOW TAG VALUES";
      measurement = this.target.measurement;
      policy = this.target.policy;
    } else if (type === "MEASUREMENTS") {
      query = "SHOW MEASUREMENTS";
      if (withMeasurementFilter) {
        query += " WITH MEASUREMENT =~ /" + withMeasurementFilter + "/";
      }
    } else if (type === "FIELDS") {
      measurement = this.target.measurement;
      policy = this.target.policy;

      if (!measurement.match("^/.*/")) {
        measurement = '"' + measurement + '"';

        if (policy && policy !== "default") {
          policy = '"' + policy + '"';
          measurement = policy + "." + measurement;
        }
      }

      return "SHOW FIELD KEYS FROM " + measurement;
    } else if (type === "RETENTION POLICIES") {
      query = 'SHOW RETENTION POLICIES on "' + this.database + '"';
      return query;
    }

    if (measurement) {
      if (!measurement.match("^/.*/") && !measurement.match(/^merge\(.*\)/)) {
        measurement = '"' + measurement + '"';
      }

      if (policy && policy !== "default") {
        policy = '"' + policy + '"';
        measurement = policy + "." + measurement;
      }

      query += " FROM " + measurement;
    }

    if (withKey) {
      query += ' WITH KEY = "' + withKey + '"';
    }

    if (this.target.tags && this.target.tags.length > 0) {
      var whereConditions = _.reduce(
        this.target.tags,
        function(memo, tag) {
          // do not add a condition for the key we want to explore for
          if (tag.key === withKey) {
            return memo;
          }
          memo.push(renderTagCondition(tag, memo.length));
          return memo;
        },
        []
      );

      if (whereConditions.length > 0) {
        query += " WHERE " + whereConditions.join(" ");
      }
    }
    if (type === "MEASUREMENTS") {
      query += " LIMIT 100";
      //Solve issue #2524 by limiting the number of measurements returned
      //LIMIT must be after WITH MEASUREMENT and WHERE clauses
      //This also could be used for TAG KEYS and TAG VALUES, if desired
    }
    return query;
  }
}