import { useEffect, useMemo, useState } from 'react';

import { DataQuery, SelectableValue } from '@grafana/data';
import { InlineField, InlineFieldRow, InputActionMeta, Select } from '@grafana/ui';

import { TempoDatasource } from './datasource';
import { OPTIONS_LIMIT } from './language_provider';

export enum TempoVariableQueryType {
  LabelNames,
  LabelValues,
}

export interface TempoVariableQuery extends DataQuery {
  type: TempoVariableQueryType;
  label?: string;
  stream?: string;
}

const variableOptions = [
  { label: 'Label names', value: TempoVariableQueryType.LabelNames },
  { label: 'Label values', value: TempoVariableQueryType.LabelValues },
];

const refId = 'TempoDatasourceVariableQueryEditor-VariableQuery';

export type TempoVariableQueryEditorProps = {
  onChange: (value: TempoVariableQuery) => void;
  query: TempoVariableQuery;
  datasource: TempoDatasource;
};

export const TempoVariableQueryEditor = ({ onChange, query, datasource }: TempoVariableQueryEditorProps) => {
  const [label, setLabel] = useState(query.label || '');
  const [type, setType] = useState<number | undefined>(query.type);
  const [labelOptions, setLabelOptions] = useState<Array<SelectableValue<string>>>([]);
  const [labelQuery, setLabelQuery] = useState<string>('');

  useEffect(() => {
    if (type === TempoVariableQueryType.LabelValues) {
      datasource.labelNamesQuery().then((labelNames: Array<{ text: string }>) => {
        setLabelOptions(labelNames.map(({ text }) => ({ label: text, value: text })));
      });
    }
  }, [datasource, query, type]);

  const options = useMemo(() => {
    if (labelQuery.length === 0) {
      return labelOptions.slice(0, OPTIONS_LIMIT);
    }

    const queryLowerCase = labelQuery.toLowerCase();
    return labelOptions
      .filter((tag) => {
        if (tag.value && tag.value.length > 0) {
          return tag.value.toLowerCase().includes(queryLowerCase);
        }
        return false;
      })
      .slice(0, OPTIONS_LIMIT);
  }, [labelQuery, labelOptions]);

  const onQueryTypeChange = (newType: SelectableValue<TempoVariableQueryType>) => {
    setType(newType.value);
    if (newType.value !== undefined) {
      onChange({
        type: newType.value,
        label,
        refId,
      });
    }
  };

  const onLabelChange = (newLabel: SelectableValue<string>) => {
    const newLabelValue = newLabel.value || '';
    setLabel(newLabelValue);
    if (type !== undefined) {
      onChange({
        type,
        label: newLabelValue,
        refId,
      });
    }
  };

  const handleBlur = () => {
    if (type !== undefined) {
      onChange({ type, label, refId });
    }
  };

  return (
    <>
      <InlineFieldRow>
        <InlineField label="Query type" labelWidth={20}>
          <Select
            aria-label="Query type"
            onChange={onQueryTypeChange}
            onBlur={handleBlur}
            value={type}
            options={variableOptions}
            width={32}
          />
        </InlineField>
      </InlineFieldRow>

      {type === TempoVariableQueryType.LabelValues && (
        <InlineFieldRow>
          <InlineField label="Label" labelWidth={20}>
            <Select
              aria-label="Label"
              onChange={onLabelChange}
              onBlur={handleBlur}
              onInputChange={(value: string, { action }: InputActionMeta) => {
                if (action === 'input-change') {
                  setLabelQuery(value);
                }
              }}
              onCloseMenu={() => setLabelQuery('')}
              value={{ label, value: label }}
              options={options}
              width={32}
              allowCustomValue
              virtualized
            />
          </InlineField>
        </InlineFieldRow>
      )}
    </>
  );
};
