import _ from "lodash";

export default class PrometheusMetricFindQuery {
  datasource: any;
  query: any;
  range: any;

  constructor(datasource, query, timeSrv) {
    this.datasource = datasource;
    this.query = query;
    this.range = timeSrv.timeRange();
  }

  process() {
    var label_values_regex = /^label_values\((?:(.+),\s*)?([a-zA-Z_][a-zA-Z0-9_]+)\)$/;
    var metric_names_regex = /^metrics\((.+)\)$/;
    var query_result_regex = /^query_result\((.+)\)$/;

    var label_values_query = this.query.match(label_values_regex);
    if (label_values_query) {
      if (label_values_query[1]) {
        return this.labelValuesQuery(
          label_values_query[2],
          label_values_query[1]
        );
      } else {
        return this.labelValuesQuery(label_values_query[2], null);
      }
    }

    var metric_names_query = this.query.match(metric_names_regex);
    if (metric_names_query) {
      return this.metricNameQuery(metric_names_query[1]);
    }

    var query_result_query = this.query.match(query_result_regex);
    if (query_result_query) {
      return this.queryResultQuery(query_result_query[1]);
    }

    // if query contains full metric name, return metric name and label list
    return this.metricNameAndLabelsQuery(this.query);
  }

  labelValuesQuery(label, metric) {
    var url;

    if (!metric) {
      // return label values globally
      url = "/api/v1/label/" + label + "/values";

      return this.datasource._request("GET", url).then(function(result) {
        return _.map(result.data.data, function(value) {
          return { text: value };
        });
      });
    } else {
      var start = this.datasource.getPrometheusTime(this.range.from, false);
      var end = this.datasource.getPrometheusTime(this.range.to, true);
      url =
        "/api/v1/series?match[]=" +
        encodeURIComponent(metric) +
        "&start=" +
        start +
        "&end=" +
        end;

      return this.datasource._request("GET", url).then(function(result) {
        var _labels = _.map(result.data.data, function(metric) {
          return metric[label] || '';
        }).filter(function(label) { return label !== ''; });

        return _.uniq(_labels).map(function(metric) {
          return {
            text: metric,
            expandable: true
          };
        });
      });
    }
  }

  metricNameQuery(metricFilterPattern) {
    var url = "/api/v1/label/__name__/values";

    return this.datasource._request("GET", url).then(function(result) {
      return _.chain(result.data.data)
        .filter(function(metricName) {
          var r = new RegExp(metricFilterPattern);
          return r.test(metricName);
        })
        .map(function(matchedMetricName) {
          return {
            text: matchedMetricName,
            expandable: true
          };
        })
        .value();
    });
  }

  queryResultQuery(query) {
    var end = this.datasource.getPrometheusTime(this.range.to, true);
    return this.datasource
      .performInstantQuery({ expr: query }, end)
      .then(function(result) {
        return _.map(result.data.data.result, function(metricData) {
          var text = metricData.metric.__name__ || "";
          delete metricData.metric.__name__;
          text +=
            "{" +
            _.map(metricData.metric, function(v, k) {
              return k + '="' + v + '"';
            }).join(",") +
            "}";
          text += " " + metricData.value[1] + " " + metricData.value[0] * 1000;

          return {
            text: text,
            expandable: true
          };
        });
      });
  }

  metricNameAndLabelsQuery(query) {
    var start = this.datasource.getPrometheusTime(this.range.from, false);
    var end = this.datasource.getPrometheusTime(this.range.to, true);
    var url =
      "/api/v1/series?match[]=" +
      encodeURIComponent(query) +
      "&start=" +
      start +
      "&end=" +
      end;

    var self = this;
    return this.datasource._request("GET", url).then(function(result) {
      return _.map(result.data.data, function(metric) {
        return {
          text: self.datasource.getOriginalMetricName(metric),
          expandable: true
        };
      });
    });
  }
}