<?php
/**
 * Read-only WordPress debug log resolver.
 *
 * @package ActionPanelAI
 */

namespace ActionPanelAI\Services;

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Resolves and inspects the configured WordPress debug log at read time.
 */
class DebugLogInspector {
	/**
	 * Constructor.
	 *
	 * @param bool        $debug_enabled    Whether WP_DEBUG is enabled.
	 * @param mixed       $debug_log_setting Raw WP_DEBUG_LOG value.
	 * @param string      $content_dir      WordPress content directory.
	 */
	public function __construct(
		private bool $debug_enabled,
		private mixed $debug_log_setting,
		private string $content_dir
	) {
	}

	/**
	 * Build an inspector from the current WordPress environment.
	 */
	public static function from_environment(): self {
		return new self(
			defined( 'WP_DEBUG' ) && self::truthy_constant( WP_DEBUG ),
			defined( 'WP_DEBUG_LOG' ) ? WP_DEBUG_LOG : false,
			defined( 'WP_CONTENT_DIR' ) ? (string) WP_CONTENT_DIR : ''
		);
	}

	/**
	 * Interpret boolean-like constants without treating the string "false" as enabled.
	 *
	 * @param mixed $value Constant value.
	 */
	private static function truthy_constant( mixed $value ): bool {
		if ( is_bool( $value ) ) {
			return $value;
		}

		if ( is_int( $value ) ) {
			return 0 !== $value;
		}

		if ( is_string( $value ) ) {
			return in_array( strtolower( trim( $value ) ), array( '1', 'true', 'on', 'yes' ), true );
		}

		return false;
	}

	/**
	 * Return debug log availability details.
	 */
	public function inspect(): array {
		if ( ! $this->debug_enabled ) {
			return $this->unavailable( 'wp_debug_disabled', '' );
		}

		$path = $this->configured_path();
		if ( '' === $path ) {
			return $this->unavailable( 'not_configured', '' );
		}

		if ( ! $this->is_absolute_path( $path ) ) {
			return $this->unavailable( 'not_configured', $path );
		}

		if ( ! file_exists( $path ) ) {
			return $this->unavailable( 'not_created', $path );
		}

		if ( ! is_readable( $path ) ) {
			return $this->unavailable( 'not_readable', $path );
		}

		return array(
			'status'  => 'available',
			'reason'  => '',
			'message' => esc_html__( 'Debug log file is available and readable.', 'actionpanel-ai' ),
			'path'    => $path,
		);
	}

	/**
	 * Resolve the configured debug log path.
	 */
	private function configured_path(): string {
		if ( true === $this->debug_log_setting || 1 === $this->debug_log_setting ) {
			return $this->default_debug_log_path();
		}

		if ( is_string( $this->debug_log_setting ) ) {
			$value = trim( $this->debug_log_setting );
			if ( in_array( strtolower( $value ), array( '1', 'true' ), true ) ) {
				return $this->default_debug_log_path();
			}
			return $value;
		}

		return '';
	}

	/**
	 * Build the default debug.log path for boolean WP_DEBUG_LOG forms.
	 */
	private function default_debug_log_path(): string {
		$content_dir = rtrim( $this->content_dir, '/\\' );
		return '' === $content_dir ? '' : $content_dir . '/debug.log';
	}

	/**
	 * Return a structured unavailable result.
	 */
	private function unavailable( string $reason, string $path ): array {
		return array(
			'status'  => 'unavailable',
			'reason'  => $reason,
			'message' => $this->message_for_reason( $reason ),
			'path'    => $path,
		);
	}

	/**
	 * Return administrator-facing text for an unavailable debug log.
	 */
	private function message_for_reason( string $reason ): string {
		if ( 'wp_debug_disabled' === $reason ) {
			return esc_html__( 'Log reads require WP_DEBUG to be enabled.', 'actionpanel-ai' );
		}

		if ( 'not_configured' === $reason ) {
			return esc_html__( 'Set WP_DEBUG_LOG to true or an absolute file path before using log reads.', 'actionpanel-ai' );
		}

		if ( 'not_created' === $reason ) {
			return esc_html__( 'The configured WP_DEBUG_LOG file does not exist yet.', 'actionpanel-ai' );
		}

		if ( 'not_readable' === $reason ) {
			return esc_html__( 'The configured WP_DEBUG_LOG file is not readable by PHP.', 'actionpanel-ai' );
		}

		return esc_html__( 'No readable WordPress debug log file is configured.', 'actionpanel-ai' );
	}

	/**
	 * Return whether the path is absolute on Unix or Windows.
	 */
	private function is_absolute_path( string $path ): bool {
		return '' !== $path && (
			str_starts_with( $path, '/' ) ||
			1 === preg_match( '/^[A-Za-z]:[\\\\\\/]/', $path )
		);
	}
}