import { css } from '@emotion/css';
import { Controller, useFormContext } from 'react-hook-form';

import { DataSourceInstanceSettings, GrafanaTheme2 } from '@grafana/data';
import { Card, Field, FieldSet, Input, useStyles2 } from '@grafana/ui';
import { Trans, t } from 'app/core/internationalization';
import { DataSourcePicker } from 'app/features/datasources/components/picker/DataSourcePicker';
import { getDatasourceSrv } from 'app/features/plugins/datasource_srv';

import { getVariableUsageInfo } from '../../explore/utils/links';

import { TransformationsEditor } from './TransformationsEditor';
import { useCorrelationsFormContext } from './correlationsFormContext';
import { FormDTO } from './types';
import { getInputId } from './utils';

const getStyles = (theme: GrafanaTheme2) => ({
  label: css({
    maxWidth: theme.spacing(80),
  }),
  variable: css({
    fontFamily: theme.typography.fontFamilyMonospace,
    fontWeight: theme.typography.fontWeightMedium,
  }),
});

const getFormText = (queryType: string, dataSourceName?: string) => {
  if (queryType === 'query') {
    return {
      title: t(
        'correlations.source-form.query-title',
        'Configure the data source that will link to {{dataSourceName}} (Step 3 of 3)',
        { dataSourceName }
      ),
      descriptionPre: t(
        'correlations.source-form.description-query-pre',
        'You have used following variables in the target query:'
      ),
      heading: t('correlations.source-form.heading-query', 'Variables used in the target query'),
    };
  } else {
    return {
      title: t(
        'correlations.source-form.external-title',
        'Configure the data source that will use the URL (Step 3 of 3)'
      ),
      descriptionPre: t(
        'correlations.source-form.description-external-pre',
        'You have used following variables in the target URL:'
      ),
      heading: t('correlations.source-form.heading-external', 'Variables used in the target URL'),
    };
  }
};

export const ConfigureCorrelationSourceForm = () => {
  const { control, formState, register, getValues } = useFormContext<FormDTO>();
  const styles = useStyles2(getStyles);
  const withDsUID = (fn: Function) => (ds: DataSourceInstanceSettings) => fn(ds.uid);

  const { correlation, readOnly } = useCorrelationsFormContext();

  const currentTargetQuery = getValues('config.target');
  const currentType = getValues('type');
  const variables = getVariableUsageInfo(currentTargetQuery, {}).variables.map(
    (variable) => variable.variableName + (variable.fieldPath ? `.${variable.fieldPath}` : '')
  );
  const dataSourceName = getDatasourceSrv().getInstanceSettings(getValues('targetUID'))?.name;

  const formText = getFormText(currentType, dataSourceName);

  function VariableList() {
    return (
      <>
        {variables.map((name, i) => (
          <span className={styles.variable} key={i}>
            {name}
            {i < variables.length - 1 ? ', ' : ''}
          </span>
        ))}
      </>
    );
  }

  return (
    <>
      <FieldSet label={formText.title}>
        <Trans i18nKey="correlations.source-form.sub-text">
          <p>
            Define what data source will display the correlation, and what data will replace previously defined
            variables.
          </p>
        </Trans>
        <Controller
          control={control}
          name="sourceUID"
          rules={{
            required: {
              value: true,
              message: t('correlations.source-form.control-required', 'This field is required.'),
            },
          }}
          render={({ field: { onChange, value } }) => (
            <Field
              label={t('correlations.source-form.source-label', 'Source')}
              description={t(
                'correlations.source-form.source-description',
                'Results from selected source data source have links displayed in the panel'
              )}
              htmlFor="source"
              invalid={!!formState.errors.sourceUID}
              error={formState.errors.sourceUID?.message}
            >
              <DataSourcePicker
                onChange={withDsUID(onChange)}
                noDefault
                current={value}
                inputId="source"
                width={32}
                disabled={correlation !== undefined}
              />
            </Field>
          )}
        />

        <Field
          label={t('correlations.source-form.results-label', 'Results field')}
          description={t(
            'correlations.source-form.results-description',
            'The link will be shown next to the value of this field'
          )}
          className={styles.label}
          invalid={!!formState.errors?.config?.field}
          error={formState.errors?.config?.field?.message}
        >
          <Input
            id={getInputId('field', correlation)}
            {...register('config.field', {
              required: t('correlations.source-form.results-required', 'This field is required.'),
            })}
            readOnly={readOnly}
          />
        </Field>
        {variables.length > 0 && (
          <Card>
            <Card.Heading>{formText.heading}</Card.Heading>
            <Card.Description>
              {formText.descriptionPre}
              <VariableList />
              <br />
              <Trans i18nKey="correlations.source-form.description">
                A data point needs to provide values to all variables as fields or as transformations output to make the
                correlation button appear in the visualization.
                <br />
                Note: Not every variable needs to be explicitly defined below. A transformation such as{' '}
                <span className={styles.variable}>logfmt</span> will create variables for every key/value pair.
              </Trans>
            </Card.Description>
          </Card>
        )}
        <TransformationsEditor readOnly={readOnly} />
      </FieldSet>
    </>
  );
};
