Refactor: Split cost reporting into separate class

Extract read-only reporting methods from PRAutoBlogger_Cost_Tracker into a new
PRAutoBlogger_Cost_Reporter class. This reduces Cost_Tracker from 313 to 206
lines and Reporter to 141 lines, both under the 300-line cap.

Changed files:
- Create includes/core/class-cost-reporter.php with reporting methods:
  * get_monthly_spend(): float
  * get_daily_spend(int $days = 30): array
  * get_spend_by_stage(string $start_date, string $end_date): array
  * get_budget_utilization(): float

- Update includes/core/class-cost-tracker.php:
  * Remove reporting methods
  * Update is_budget_exceeded() and would_exceed_budget() to use Cost_Reporter
  * Keep get_current_run_cost() (tracks current pipeline run only)
  * Add @see cross-reference to Cost_Reporter

- Update templates and admin classes to instantiate Cost_Reporter:
  * templates/admin/metrics-page.php
  * templates/admin/settings-page.php
  * includes/admin/class-admin-notices.php
  * includes/admin/class-dashboard-widget.php

- Split tests/unit/Core/CostTrackerTest.php:
  * Create tests/unit/Core/CostReporterTest.php for reporter methods
  * Keep run ID and budget enforcement tests in CostTrackerTest

Autoloader automatically discovers PRAutoBlogger_Cost_Reporter class.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

includes/admin/class-admin-notices.php

@@ -5,7 +5,7 @@ declare(strict_types=1);
  * Displays admin notices for onboarding, errors, and budget warnings.
  *
  * Triggered by: PRAutoBlogger::register_admin_hooks() on `admin_notices`.
- * Dependencies: PRAutoBlogger_Cost_Tracker (for budget warnings).
+ * Dependencies: PRAutoBlogger_Cost_Reporter (for budget warnings).
  *
  * @see class-prautoblogger.php — Registers the hook.
  */
@@ -51,8 +51,8 @@ class PRAutoBlogger_Admin_Notices {
 	 * @return void
 	 */
 	private function check_budget_notice(): void {
-		$cost_tracker = new PRAutoBlogger_Cost_Tracker();
+		$cost_reporter = new PRAutoBlogger_Cost_Reporter();
-		$utilization  = $cost_tracker->get_budget_utilization();
+		$utilization   = $cost_reporter->get_budget_utilization();
 
 		if ( $utilization >= 100.0 ) {
 			printf(

includes/admin/class-dashboard-widget.php

@@ -8,7 +8,7 @@ declare(strict_types=1);
  * and budget utilization.
  *
  * Triggered by: Could be registered via wp_dashboard_setup hook.
- * Dependencies: PRAutoBlogger_Cost_Tracker.
+ * Dependencies: PRAutoBlogger_Cost_Reporter.
  *
  * @see class-prautoblogger.php — Can register this on wp_dashboard_setup.
  */
@@ -37,10 +37,10 @@ class PRAutoBlogger_Dashboard_Widget {
 	 * @return void
 	 */
 	public function render_widget(): void {
-		$cost_tracker = new PRAutoBlogger_Cost_Tracker();
+		$cost_reporter = new PRAutoBlogger_Cost_Reporter();
-		$monthly_spend = $cost_tracker->get_monthly_spend();
+		$monthly_spend = $cost_reporter->get_monthly_spend();
 		$budget        = (float) get_option( 'prautoblogger_monthly_budget_usd', 50.00 );
-		$utilization   = $cost_tracker->get_budget_utilization();
+		$utilization   = $cost_reporter->get_budget_utilization();
 
 		$next_run = wp_next_scheduled( 'prautoblogger_daily_generation' );
 

includes/core/class-cost-reporter.php

@@ -0,0 +1,141 @@
+<?php
+declare(strict_types=1);
+
+/**
+ * Provides historical cost reporting and analysis methods.
+ *
+ * Extracted from PRAutoBlogger_Cost_Tracker, this class handles all read-only
+ * reporting queries: monthly spend, daily spend trends, spend-by-stage breakdowns,
+ * and budget utilization percentage.
+ *
+ * Called by: Metrics dashboard, admin notices, and dashboard widget.
+ * Dependencies: WordPress $wpdb, get_option() for budget configuration.
+ *
+ * @see core/class-cost-tracker.php    — Complementary class for logging and budget enforcement.
+ * @see admin/class-metrics-page.php   — Displays cost reports.
+ * @see admin/class-admin-notices.php  — Shows budget warnings via get_budget_utilization().
+ * @see admin/class-dashboard-widget.php — Displays current month costs.
+ */
+class PRAutoBlogger_Cost_Reporter {
+
+	/**
+	 * Get total estimated spend for the current calendar month.
+	 *
+	 * @return float Total USD spend this month.
+	 */
+	public function get_monthly_spend(): float {
+		global $wpdb;
+		if ( null === $wpdb ) {
+			return 0.0;
+		}
+
+		$table = $wpdb->prefix . 'prautoblogger_generation_log';
+
+		$first_of_month = gmdate( 'Y-m-01 00:00:00' );
+
+		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery
+		$result = $wpdb->get_var(
+			$wpdb->prepare(
+				"SELECT COALESCE(SUM(estimated_cost), 0) FROM {$table} WHERE created_at >= %s AND response_status = 'success'",
+				$first_of_month
+			)
+		);
+
+		return (float) $result;
+	}
+
+	/**
+	 * Get daily spend for the last N days (for the metrics dashboard chart).
+	 *
+	 * @param int $days Number of days to look back.
+	 *
+	 * @return array<string, float> Associative array of date => total_cost.
+	 */
+	public function get_daily_spend( int $days = 30 ): array {
+		global $wpdb;
+		if ( null === $wpdb ) {
+			return [];
+		}
+
+		$table = $wpdb->prefix . 'prautoblogger_generation_log';
+
+		$start_date = gmdate( 'Y-m-d', time() - ( $days * DAY_IN_SECONDS ) );
+
+		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery
+		$results = $wpdb->get_results(
+			$wpdb->prepare(
+				"SELECT DATE(created_at) as day, SUM(estimated_cost) as total_cost
+				FROM {$table}
+				WHERE created_at >= %s AND response_status = 'success'
+				GROUP BY DATE(created_at)
+				ORDER BY day ASC",
+				$start_date . ' 00:00:00'
+			),
+			ARRAY_A
+		);
+
+		$daily = [];
+		foreach ( ( $results ?: [] ) as $row ) {
+			$daily[ $row['day'] ] = (float) $row['total_cost'];
+		}
+
+		return $daily;
+	}
+
+	/**
+	 * Get spend breakdown by pipeline stage for a given period.
+	 *
+	 * @param string $start_date Start date (Y-m-d).
+	 * @param string $end_date   End date (Y-m-d).
+	 *
+	 * @return array<string, array{cost: float, tokens: int, calls: int}> Breakdown by stage.
+	 */
+	public function get_spend_by_stage( string $start_date, string $end_date ): array {
+		global $wpdb;
+		if ( null === $wpdb ) {
+			return [];
+		}
+
+		$table = $wpdb->prefix . 'prautoblogger_generation_log';
+
+		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery
+		$results = $wpdb->get_results(
+			$wpdb->prepare(
+				"SELECT stage,
+					SUM(estimated_cost) as total_cost,
+					SUM(prompt_tokens + completion_tokens) as total_tokens,
+					COUNT(*) as call_count
+				FROM {$table}
+				WHERE created_at BETWEEN %s AND %s AND response_status = 'success'
+				GROUP BY stage",
+				$start_date . ' 00:00:00',
+				$end_date . ' 23:59:59'
+			),
+			ARRAY_A
+		);
+
+		$breakdown = [];
+		foreach ( ( $results ?: [] ) as $row ) {
+			$breakdown[ $row['stage'] ] = [
+				'cost'   => (float) $row['total_cost'],
+				'tokens' => (int) $row['total_tokens'],
+				'calls'  => (int) $row['call_count'],
+			];
+		}
+
+		return $breakdown;
+	}
+
+	/**
+	 * Get budget utilization percentage for the current month.
+	 *
+	 * @return float Percentage (0-100+). Can exceed 100 if overspent.
+	 */
+	public function get_budget_utilization(): float {
+		$budget = (float) get_option( 'prautoblogger_monthly_budget_usd', 50.00 );
+		if ( $budget <= 0 ) {
+			return 0.0;
+		}
+		return ( $this->get_monthly_spend() / $budget ) * 100.0;
+	}
+}

includes/core/class-cost-tracker.php

@@ -2,8 +2,7 @@
 declare(strict_types=1);
 
 /**
- * Tracks all API costs, enforces monthly budget limits, and provides
+ * Tracks all API costs and enforces monthly budget limits.
- * cost reporting data for the admin dashboard.
  *
  * Every LLM API call in the plugin is logged through this class. The budget
  * enforcement is a hard stop — if the monthly budget is exceeded, no further
@@ -16,7 +15,8 @@ declare(strict_types=1);
  * @see core/class-content-analyzer.php  — Calls log_api_call() after analysis.
  * @see core/class-content-generator.php — Calls log_api_call() after each stage.
  * @see core/class-chief-editor.php      — Calls log_api_call() after review.
- * @see admin/class-metrics-page.php     — Displays cost data from this class.
+ * @see core/class-cost-reporter.php     — Extracted reporting methods (read-only queries).
+ * @see admin/class-metrics-page.php     — Displays cost data via Cost_Reporter.
  * @see ARCHITECTURE.md                  — prab_generation_log table schema.
  */
 class PRAutoBlogger_Cost_Tracker {
@@ -127,7 +127,8 @@ class PRAutoBlogger_Cost_Tracker {
 			return false;
 		}
 
-		$monthly_spend = $this->get_monthly_spend();
+		$reporter      = new PRAutoBlogger_Cost_Reporter();
+		$monthly_spend = $reporter->get_monthly_spend();
 
 		// Round to 4 decimal places (0.01 cent precision) to avoid
 		// floating-point representation artifacts triggering false positives.
@@ -189,32 +190,11 @@ class PRAutoBlogger_Cost_Tracker {
 			return false;
 		}
 
-		$projected = $this->get_monthly_spend() + $estimated_cost_usd;
+		$reporter  = new PRAutoBlogger_Cost_Reporter();
+		$projected = $reporter->get_monthly_spend() + $estimated_cost_usd;
 		return round( $projected, 4 ) >= round( $budget, 4 );
 	}
 
-	/**
-	 * Get total estimated spend for the current calendar month.
-	 *
-	 * @return float Total USD spend this month.
-	 */
-	public function get_monthly_spend(): float {
-		global $wpdb;
-		$table = $wpdb->prefix . 'prautoblogger_generation_log';
-
-		$first_of_month = gmdate( 'Y-m-01 00:00:00' );
-
-		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery
-		$result = $wpdb->get_var(
-			$wpdb->prepare(
-				"SELECT COALESCE(SUM(estimated_cost), 0) FROM {$table} WHERE created_at >= %s AND response_status = 'success'",
-				$first_of_month
-			)
-		);
-
-		return (float) $result;
-	}
-
 	/**
 	 * Get the cost accumulated during the current pipeline run.
 	 *
@@ -223,91 +203,4 @@ class PRAutoBlogger_Cost_Tracker {
 	public function get_current_run_cost(): float {
 		return $this->current_run_cost;
 	}
-
-	/**
-	 * Get daily spend for the last N days (for the metrics dashboard chart).
-	 *
-	 * @param int $days Number of days to look back.
-	 *
-	 * @return array<string, float> Associative array of date => total_cost.
-	 */
-	public function get_daily_spend( int $days = 30 ): array {
-		global $wpdb;
-		$table = $wpdb->prefix . 'prautoblogger_generation_log';
-
-		$start_date = gmdate( 'Y-m-d', time() - ( $days * DAY_IN_SECONDS ) );
-
-		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery
-		$results = $wpdb->get_results(
-			$wpdb->prepare(
-				"SELECT DATE(created_at) as day, SUM(estimated_cost) as total_cost
-				FROM {$table}
-				WHERE created_at >= %s AND response_status = 'success'
-				GROUP BY DATE(created_at)
-				ORDER BY day ASC",
-				$start_date . ' 00:00:00'
-			),
-			ARRAY_A
-		);
-
-		$daily = [];
-		foreach ( ( $results ?: [] ) as $row ) {
-			$daily[ $row['day'] ] = (float) $row['total_cost'];
-		}
-
-		return $daily;
-	}
-
-	/**
-	 * Get spend breakdown by pipeline stage for a given period.
-	 *
-	 * @param string $start_date Start date (Y-m-d).
-	 * @param string $end_date   End date (Y-m-d).
-	 *
-	 * @return array<string, array{cost: float, tokens: int, calls: int}> Breakdown by stage.
-	 */
-	public function get_spend_by_stage( string $start_date, string $end_date ): array {
-		global $wpdb;
-		$table = $wpdb->prefix . 'prautoblogger_generation_log';
-
-		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery
-		$results = $wpdb->get_results(
-			$wpdb->prepare(
-				"SELECT stage,
-					SUM(estimated_cost) as total_cost,
-					SUM(prompt_tokens + completion_tokens) as total_tokens,
-					COUNT(*) as call_count
-				FROM {$table}
-				WHERE created_at BETWEEN %s AND %s AND response_status = 'success'
-				GROUP BY stage",
-				$start_date . ' 00:00:00',
-				$end_date . ' 23:59:59'
-			),
-			ARRAY_A
-		);
-
-		$breakdown = [];
-		foreach ( ( $results ?: [] ) as $row ) {
-			$breakdown[ $row['stage'] ] = [
-				'cost'   => (float) $row['total_cost'],
-				'tokens' => (int) $row['total_tokens'],
-				'calls'  => (int) $row['call_count'],
-			];
-		}
-
-		return $breakdown;
-	}
-
-	/**
-	 * Get budget utilization percentage for the current month.
-	 *
-	 * @return float Percentage (0-100+). Can exceed 100 if overspent.
-	 */
-	public function get_budget_utilization(): float {
-		$budget = (float) get_option( 'prautoblogger_monthly_budget_usd', 50.00 );
-		if ( $budget <= 0 ) {
-			return 0.0;
-		}
-		return ( $this->get_monthly_spend() / $budget ) * 100.0;
-	}
 }

templates/admin/metrics-page.php

@@ -9,15 +9,15 @@ if ( ! defined( 'ABSPATH' ) ) {
 	exit;
 }
 
-$cost_tracker = new PRAutoBlogger_Cost_Tracker();
+$cost_reporter = new PRAutoBlogger_Cost_Reporter();
-$monthly_spend = $cost_tracker->get_monthly_spend();
+$monthly_spend = $cost_reporter->get_monthly_spend();
 $budget        = (float) get_option( 'prautoblogger_monthly_budget_usd', 50.00 );
-$utilization   = $cost_tracker->get_budget_utilization();
+$utilization   = $cost_reporter->get_budget_utilization();
-$daily_spend   = $cost_tracker->get_daily_spend( 30 );
+$daily_spend   = $cost_reporter->get_daily_spend( 30 );
 
 $first_of_month = gmdate( 'Y-m-01' );
 $today          = gmdate( 'Y-m-d' );
-$stage_breakdown = $cost_tracker->get_spend_by_stage( $first_of_month, $today );
+$stage_breakdown = $cost_reporter->get_spend_by_stage( $first_of_month, $today );
 ?>
 <div class="wrap prautoblogger-metrics">
 	<h1><?php esc_html_e( 'PRAutoBlogger — Metrics & Costs', 'prautoblogger' ); ?></h1>

templates/admin/settings-page.php

@@ -14,8 +14,8 @@ if ( ! defined( 'ABSPATH' ) ) {
 }
 
 $active_tab     = isset( $_GET['tab'] ) ? sanitize_key( $_GET['tab'] ) : 'prautoblogger_api';
-$cost_tracker   = new PRAutoBlogger_Cost_Tracker();
+$cost_reporter  = new PRAutoBlogger_Cost_Reporter();
-$monthly_spend  = $cost_tracker->get_monthly_spend();
+$monthly_spend  = $cost_reporter->get_monthly_spend();
 $budget         = (float) get_option( 'prautoblogger_monthly_budget_usd', 50.00 );
 $utilization    = $budget > 0 ? ( $monthly_spend / $budget ) * 100.0 : 0;
 $next_run       = wp_next_scheduled( 'prautoblogger_daily_generation' );

tests/unit/Core/CostReporterTest.php

@@ -0,0 +1,93 @@
+<?php
+/**
+ * Tests for PRAutoBlogger_Cost_Reporter.
+ *
+ * Validates monthly spend, daily spend trends, spend-by-stage breakdowns,
+ * and budget utilization reporting methods.
+ *
+ * @package PRAutoBlogger\Tests\Core
+ */
+
+namespace PRAutoBlogger\Tests\Core;
+
+use PRAutoBlogger\Tests\BaseTestCase;
+use Brain\Monkey\Functions;
+
+class CostReporterTest extends BaseTestCase {
+
+    /**
+     * @var \PHPUnit\Framework\MockObject\MockObject Mock $wpdb instance.
+     */
+    private $wpdb;
+
+    protected function setUp(): void {
+        parent::setUp();
+
+        $this->wpdb = $this->create_mock_wpdb();
+        $GLOBALS['wpdb'] = $this->wpdb;
+
+        // CostReporter methods call get_option for budget settings.
+        $this->stub_get_option( [
+            'prautoblogger_monthly_budget_usd' => '50.00',
+        ] );
+
+        // Stub current_time used in date-based queries.
+        $this->stub_current_time( '2026-04-12 10:00:00' );
+    }
+
+    protected function tearDown(): void {
+        unset( $GLOBALS['wpdb'] );
+        parent::tearDown();
+    }
+
+    /**
+     * Test get_monthly_spend returns float.
+     */
+    public function test_get_monthly_spend_returns_float(): void {
+        $this->wpdb->method( 'prepare' )->willReturn( 'prepared' );
+        $this->wpdb->method( 'get_var' )->willReturn( '10.50' );
+
+        $reporter = new \PRAutoBlogger_Cost_Reporter();
+        $spend = $reporter->get_monthly_spend();
+
+        $this->assertIsFloat( $spend );
+        $this->assertGreaterThanOrEqual( 0.0, $spend );
+    }
+
+    /**
+     * Test get_daily_spend returns array.
+     */
+    public function test_get_daily_spend_returns_array(): void {
+        $this->wpdb->method( 'prepare' )->willReturn( 'prepared' );
+        $this->wpdb->method( 'get_results' )->willReturn( [] );
+
+        $reporter = new \PRAutoBlogger_Cost_Reporter();
+        $daily = $reporter->get_daily_spend( 30 );
+
+        $this->assertIsArray( $daily );
+    }
+
+    /**
+     * Test get_spend_by_stage returns array.
+     */
+    public function test_get_spend_by_stage_returns_array(): void {
+        $this->wpdb->method( 'prepare' )->willReturn( 'prepared' );
+        $this->wpdb->method( 'get_results' )->willReturn( [] );
+
+        $reporter = new \PRAutoBlogger_Cost_Reporter();
+        $spend = $reporter->get_spend_by_stage( '2026-04-01', '2026-04-30' );
+
+        $this->assertIsArray( $spend );
+    }
+
+    /**
+     * Test get_budget_utilization returns float between 0 and 100+.
+     */
+    public function test_get_budget_utilization_returns_float(): void {
+        $reporter = new \PRAutoBlogger_Cost_Reporter();
+        $utilization = $reporter->get_budget_utilization();
+
+        $this->assertIsFloat( $utilization );
+        $this->assertGreaterThanOrEqual( 0.0, $utilization );
+    }
+}

tests/unit/Core/CostTrackerTest.php

@@ -68,20 +68,6 @@ class CostTrackerTest extends BaseTestCase {
         $this->assertFalse( $tracker->is_budget_exceeded() );
     }
 
-    /**
-     * Test get_monthly_spend returns float.
-     */
-    public function test_get_monthly_spend_returns_float(): void {
-        $this->wpdb->method( 'prepare' )->willReturn( 'prepared' );
-        $this->wpdb->method( 'get_var' )->willReturn( '10.50' );
-
-        $tracker = new \PRAutoBlogger_Cost_Tracker();
-        $spend = $tracker->get_monthly_spend();
-
-        $this->assertIsFloat( $spend );
-        $this->assertGreaterThanOrEqual( 0.0, $spend );
-    }
-
     /**
      * Test get_current_run_cost returns float.
      */
@@ -98,43 +84,6 @@ class CostTrackerTest extends BaseTestCase {
         $this->assertGreaterThanOrEqual( 0.0, $cost );
     }
 
-    /**
-     * Test get_daily_spend returns array.
-     */
-    public function test_get_daily_spend_returns_array(): void {
-        $this->wpdb->method( 'prepare' )->willReturn( 'prepared' );
-        $this->wpdb->method( 'get_results' )->willReturn( [] );
-
-        $tracker = new \PRAutoBlogger_Cost_Tracker();
-        $daily = $tracker->get_daily_spend( 30 );
-
-        $this->assertIsArray( $daily );
-    }
-
-    /**
-     * Test get_spend_by_stage returns array.
-     */
-    public function test_get_spend_by_stage_returns_array(): void {
-        $this->wpdb->method( 'prepare' )->willReturn( 'prepared' );
-        $this->wpdb->method( 'get_results' )->willReturn( [] );
-
-        $tracker = new \PRAutoBlogger_Cost_Tracker();
-        $spend = $tracker->get_spend_by_stage( '2026-04-01', '2026-04-30' );
-
-        $this->assertIsArray( $spend );
-    }
-
-    /**
-     * Test get_budget_utilization returns float between 0 and 1.
-     */
-    public function test_get_budget_utilization_returns_float(): void {
-        $tracker = new \PRAutoBlogger_Cost_Tracker();
-        $utilization = $tracker->get_budget_utilization();
-
-        $this->assertIsFloat( $utilization );
-        $this->assertGreaterThanOrEqual( 0.0, $utilization );
-    }
-
     /**
      * Test log_api_call with mock database.
      */