<?php
// phpcs:ignore WordPress.Files.FileName.InvalidClassFileName -- class naming convention differs from WordPress standard
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(
			$wpdb->prepare(  // phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared
				"SELECT COALESCE(SUM(estimated_cost), 0) FROM {$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 array();
		}

		$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(
			$wpdb->prepare(
				"SELECT DATE(created_at) as day, SUM(estimated_cost) as total_cost  // phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared
				FROM {$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 = array();
		foreach ( ( $results ?: array() ) 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 array();
		}

		$table = $wpdb->prefix . 'prautoblogger_generation_log';

		// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery
		$results = $wpdb->get_results(
			$wpdb->prepare(
				"SELECT stage,
					SUM(estimated_cost) as total_cost,
					SUM(prompt_tokens + completion_tokens) as total_tokens,
					COUNT(*) as call_count  // phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared
				FROM {$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 = array();
		foreach ( ( $results ?: array() ) as $row ) {
			$breakdown[ $row['stage'] ] = array(
				'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;
	}
}