[Simple Analytics] Add Data Layer & Form Event Tracking

[alaca]

Description of the Change

• Created a custom database table ({prefix}_mailchimp_sf_form_analytics) for daily aggregated form analytics, with columns for list_id, form_id, event_date, views, and submissions (unique key on list_id, form_id, event_date)
• Implement client-side form view tracking that adds data-list-id attribute to all form types (block, widget, shortcode) and
  fires an AJAX POST on page load, deduplicated per list_id
• Hook into successful form submissions via a new mailchimp_sf_form_submission_success action to increment daily submission
• Table creation runs on plugin activation and via the upgrade routine for existing installs

Closes #198

How to test the Change

• Activate the plugin on a fresh install and verify the wp_mailchimp_sf_form_analytics table is created
• Visit a page with a Mailchimp signup form and verify a view is recorded in the analytics table for the correct list_id and
  today's date
• Place multiple forms (different lists) on one page and verify each list gets its own view count
• Submit a form successfully and verify the submission count increments
• Submit a form with invalid data (e.g., missing email) and verify no submission is tracked
• Navigate to Mailchimp > Analytics in wp-admin and verify that test data is displayed

Changelog Entry

Created a custom database table (mailchimp_sf_form_analytics) for daily aggregated form analytics
Implemented client-side form view tracking via AJAX

Credits

Props @alaca

Checklist:

• I agree to follow this project's Code of Conduct.
• I have updated the documentation accordingly.
• I have added tests to cover my change.
• All new and existing tests pass.

[Copilot]

Pull request overview

Adds a new “Simple Analytics” data layer to track Mailchimp signup form views/submissions and surfaces the data in the WP Admin Analytics page.

Changes:

• Adds a custom DB table ({prefix}_mailchimp_sf_form_analytics) plus query/increment helpers and an AJAX handler for form-view tracking.
• Emits a new mailchimp_sf_form_submission_success action on successful submissions and hooks it to increment submission counts.
• Adds data-list-id to rendered forms and adds frontend JS to POST form-view events.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
mailchimp_widget.php	Adds data-list-id attribute to widget/shortcode form markup for JS tracking.
includes/blocks/mailchimp/markup.php	Adds data-list-id attribute to block form markup for JS tracking.
assets/js/mailchimp.js	Adds client-side view tracking that POSTs to admin-ajax.php.
includes/class-mailchimp-form-submission.php	Fires a new action on successful form submission for analytics hooks.
includes/class-mailchimp-analytics-data.php	New analytics storage/query class, table creation, AJAX handler, and submission tracking hook.
mailchimp.php	Loads the analytics data class, registers activation hook, localizes AJAX URL + nonce.
mailchimp_upgrade.php	Runs table creation in upgrade routine based on a stored DB version option.
includes/class-mailchimp-analytics.php	Removes trailing whitespace only.
includes/admin/templates/analytics.php	Fetches analytics data and currently outputs it via print_r() for display.

---

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[Copilot]

$end_date uses current_time('Y-m-d') (site timezone) while $start_date uses gmdate() (UTC). Since event_date is stored using current_time('Y-m-d'), mixing timezones can shift the queried range by a day on some sites. Use a consistent timezone for both (e.g., compute $start_date from current_time('timestamp') or wp_date() in site timezone).

Suggested change

	$analytics_data = new Mailchimp_Analytics_Data();
	$end_date = current_time( 'Y-m-d' );
	$start_date = gmdate( 'Y-m-d', strtotime( '-30 days' ) );
	$analytics_data = new Mailchimp_Analytics_Data();
	$current_timestamp = current_time( 'timestamp' );
	$end_date = wp_date( 'Y-m-d', $current_timestamp );
	$start_date = wp_date( 'Y-m-d', $current_timestamp - ( 30 * DAY_IN_SECONDS ) );

[Copilot]

handle_form_view() only checks that list_id is non-empty. As written, an unauthenticated request can create rows for arbitrary list_id values, which can bloat the analytics table and pollute reporting. Validate that list_id is one of the configured/known lists (e.g., from the mailchimp_sf_lists option or the active mc_list_id) and reject/ignore unknown IDs (also consider enforcing the expected length/format).

Suggested change

	$this->increment_views( $list_id );
	wp_send_json_success();
	}
	/**
	// Ensure the list ID is one of the configured/known lists to prevent
	// arbitrary IDs from polluting analytics data.
	if ( ! $this->is_valid_list_id( $list_id ) ) {
	wp_send_json_error( 'Invalid list_id.', 400 );
	}
	$this->increment_views( $list_id );
	wp_send_json_success();
	}
	/**
	* Determine whether a list ID is one of the configured/known lists.
	*
	* This helps ensure that analytics data is only recorded for legitimate lists
	* configured within the plugin options.
	*
	* @param string $list_id The list ID to validate.
	* @return bool True if the list ID is known/configured, false otherwise.
	*/
	private function is_valid_list_id( $list_id ) {
	if ( empty( $list_id ) ) {
	return false;
	}
	$valid_ids = array();
	// Collect list IDs from the stored Mailchimp lists option, if present.
	$mailchimp_lists = get_option( 'mailchimp_sf_lists' );
	if ( is_array( $mailchimp_lists ) ) {
	foreach ( $mailchimp_lists as $list ) {
	// Handle both scalar IDs and associative array structures.
	if ( is_string( $list ) || is_int( $list ) ) {
	$valid_ids[] = (string) $list;
	} elseif ( is_array( $list ) ) {
	// Common keys used to store list IDs.
	foreach ( array( 'id', 'list_id', 'mc_list_id' ) as $key ) {
	if ( isset( $list[ $key ] ) && ! empty( $list[ $key ] ) ) {
	$valid_ids[] = (string) $list[ $key ];
	}
	}
	}
	}
	}
	// Include the active Mailchimp list ID option, if set.
	$active_list_id = get_option( 'mc_list_id' );
	if ( ! empty( $active_list_id ) ) {
	$valid_ids[] = (string) $active_list_id;
	}
	// If we have no configured IDs, fail closed and do not treat arbitrary IDs as valid.
	if ( empty( $valid_ids ) ) {
	return false;
	}
	$valid_ids = array_unique( $valid_ids );
	return in_array( (string) $list_id, $valid_ids, true );
	}
	/**

[Copilot]

mailchimp_sf_load_resources() is called from admin screens for the form preview (e.g., setup page), and these localized analytics values will cause the frontend tracking code to fire in wp-admin and record “views” from administrators previewing the form. Consider only localizing analytics_ajax_url / analytics_nonce on the frontend (e.g., if ( ! is_admin() )) or otherwise gating tracking so admin previews don’t affect analytics.

[Copilot]

The new form-view tracking runs immediately when mailchimp.js is loaded, which can also execute in wp-admin contexts (the setup preview explicitly enqueues this script) and inflate view counts. Add an explicit guard to disable tracking in admin/preview contexts (or only enable when the localized analytics config indicates a real frontend render).

[Copilot]

This PR introduces new analytics behaviors (AJAX endpoint for view tracking, DB writes, and a new submission-success hook) but doesn’t add/extend automated coverage. There is an existing Cypress suite under tests/cypress; adding at least one e2e test that verifies view tracking + submission tracking increments the expected counts would help prevent regressions.

[Copilot]

The Analytics admin template is currently outputting raw data via print_r() inside <pre> blocks. This looks like debug output and will ship to production (and bypasses any intended UI/Chart rendering), making the page noisy and harder to maintain. Replace this with proper, escaped rendering (e.g., table/chart markup) or restore the placeholder until the UI is implemented.

Suggested change

	<pre><?php print_r( $totals ); // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_print_r ?></pre>
	<h3><?php esc_html_e( 'Daily Breakdown', 'mailchimp' ); ?></h3>
	<pre><?php print_r( $daily ); // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_print_r ?></pre>
	<?php if ( ! empty( $totals ) && is_array( $totals ) ) : ?>
	<table class="widefat striped">
	<thead>
	<tr>
	<th><?php esc_html_e( 'Metric', 'mailchimp' ); ?></th>
	<th><?php esc_html_e( 'Value', 'mailchimp' ); ?></th>
	</tr>
	</thead>
	<tbody>
	<?php foreach ( $totals as $metric_key => $metric_value ) : ?>
	<tr>
	<td><?php echo esc_html( $metric_key ); ?></td>
	<td>
	<?php
	if ( is_array( $metric_value ) || is_object( $metric_value ) ) {
	echo esc_html( wp_json_encode( $metric_value ) );
	} else {
	echo esc_html( (string) $metric_value );
	}
	?>
	</td>
	</tr>
	<?php endforeach; ?>
	</tbody>
	</table>
	<?php else : ?>
	<p><?php esc_html_e( 'No totals data is currently available for this period.', 'mailchimp' ); ?></p>
	<?php endif; ?>
	<h3><?php esc_html_e( 'Daily Breakdown', 'mailchimp' ); ?></h3>
	<?php if ( ! empty( $daily ) && is_array( $daily ) ) : ?>
	<?php
	$first_row = reset( $daily );
	$has_header = is_array( $first_row ) && ! empty( $first_row );
	?>
	<table class="widefat striped">
	<?php if ( $has_header ) : ?>
	<thead>
	<tr>
	<?php foreach ( array_keys( $first_row ) as $header_key ) : ?>
	<th><?php echo esc_html( $header_key ); ?></th>
	<?php endforeach; ?>
	</tr>
	</thead>
	<?php endif; ?>
	<tbody>
	<?php foreach ( $daily as $row ) : ?>
	<tr>
	<?php
	if ( is_array( $row ) ) {
	foreach ( $row as $cell_value ) {
	if ( is_array( $cell_value ) || is_object( $cell_value ) ) {
	$cell_output = wp_json_encode( $cell_value );
	} else {
	$cell_output = (string) $cell_value;
	}
	?>
	<td><?php echo esc_html( $cell_output ); ?></td>
	<?php
	}
	} else {
	if ( is_array( $row ) || is_object( $row ) ) {
	$row_output = wp_json_encode( $row );
	} else {
	$row_output = (string) $row;
	}
	?>
	<td><?php echo esc_html( $row_output ); ?></td>
	<?php } ?>
	</tr>
	<?php endforeach; ?>
	</tbody>
	</table>
	<?php else : ?>
	<p><?php esc_html_e( 'No daily analytics data is currently available for this period.', 'mailchimp' ); ?></p>
	<?php endif; ?>

[iamdharmesh]

Thanks @alaca. Overall this looks good and added few feedback/comment. Could you please check?

[iamdharmesh]

Suggested change

	const DB_VERSION = '1.0';
	const DB_VERSION = '1.0.0';

[iamdharmesh]

Maybe better to add some error handling here and log the failures.

[iamdharmesh]

Same as above.

[iamdharmesh]

Can use something like mailchimp_sf_nonce to prevent potential conflict with other plugins.

[iamdharmesh]

Suggested change

	});
	}).catch(() => {});

To prevent unhandled promise rejections in the browser console