<?php
/**
 * WordPress Coding Standard.
 *
 * @package WPCS\WordPressCodingStandards
 * @link    https://github.com/WordPress/WordPress-Coding-Standards
 * @license https://opensource.org/licenses/MIT MIT
 */

namespace WordPressCS\WordPress\Sniffs\CodeAnalysis;

use PHP_CodeSniffer\Util\Tokens;
use PHPCSUtils\BackCompat\BCFile;
use PHPCSUtils\Utils\Parentheses;
use WordPressCS\WordPress\Sniff;

/**
 * Detects variable assignments being made within conditions.
 *
 * This is a typical code smell and more often than not a comparison was intended.
 *
 * Note: this sniff does not detect variable assignments in ternaries without parentheses!
 *
 * @since 0.14.0
 * @since 3.0.0  - The generic "assignment in condition" logic has been removed from the sniff
 *                 in favour of the upstream `Generic.CodeAnalysis.AssignmentInCondition` sniff.
 *               - The sniff has been renamed from `AssignmentInCondition` to `AssignmentInTernaryCondition`.
 *
 * @link https://github.com/squizlabs/PHP_CodeSniffer/pull/1594 Upstream sniff.
 */
final class AssignmentInTernaryConditionSniff extends Sniff {

	/**
	 * Assignment tokens to trigger on.
	 *
	 * Set in the register() method.
	 *
	 * @since 0.14.0
	 *
	 * @var array
	 */
	protected $assignment_tokens = array();

	/**
	 * The tokens that indicate the start of a condition.
	 *
	 * @since 0.14.0
	 *
	 * @var array
	 */
	protected $condition_start_tokens = array();

	/**
	 * Registers the tokens that this sniff wants to listen for.
	 *
	 * @since 0.14.0
	 *
	 * @return array
	 */
	public function register() {
		$this->assignment_tokens = Tokens::$assignmentTokens;
		unset( $this->assignment_tokens[ \T_DOUBLE_ARROW ] );

		$starters                        = Tokens::$booleanOperators;
		$starters[ \T_SEMICOLON ]        = \T_SEMICOLON;
		$starters[ \T_OPEN_PARENTHESIS ] = \T_OPEN_PARENTHESIS;
		$starters[ \T_INLINE_ELSE ]      = \T_INLINE_ELSE;

		$this->condition_start_tokens = $starters;

		return array(
			\T_INLINE_THEN,
		);
	}

	/**
	 * Processes this test, when one of its tokens is encountered.
	 *
	 * @since 0.14.0
	 *
	 * @param int $stackPtr The position of the current token in the stack.
	 *
	 * @return void
	 */
	public function process_token( $stackPtr ) {

		$token = $this->tokens[ $stackPtr ];

		// Check if the condition for the ternary is bracketed.
		$prev = $this->phpcsFile->findPrevious( Tokens::$emptyTokens, ( $stackPtr - 1 ), null, true );
		if ( \T_CLOSE_PARENTHESIS === $this->tokens[ $prev ]['code'] ) {
			if ( ! isset( $this->tokens[ $prev ]['parenthesis_opener'] ) ) {
				return;
			}

			$opener = $this->tokens[ $prev ]['parenthesis_opener'];
			$closer = $prev;
		} elseif ( isset( $token['nested_parenthesis'] ) ) {
			$opener = Parentheses::getLastOpener( $this->phpcsFile, $stackPtr );
			$closer = Parentheses::getLastCloser( $this->phpcsFile, $stackPtr );

			$next_statement_closer = BCFile::findEndOfStatement( $this->phpcsFile, $stackPtr, array( \T_COLON, \T_CLOSE_PARENTHESIS, \T_CLOSE_SQUARE_BRACKET ) );
			if ( false !== $next_statement_closer && $next_statement_closer < $closer ) {
				// Parentheses are unrelated to the ternary.
				return;
			}

			$prev_statement_closer = BCFile::findStartOfStatement( $this->phpcsFile, $stackPtr, array( \T_COLON, \T_OPEN_PARENTHESIS, \T_OPEN_SQUARE_BRACKET ) );
			if ( false !== $prev_statement_closer && $opener < $prev_statement_closer ) {
				// Parentheses are unrelated to the ternary.
				return;
			}

			if ( $closer > $stackPtr ) {
				$closer = $stackPtr;
			}
		} else {
			// No parenthesis found, can't determine where the conditional part of the ternary starts.
			return;
		}

		$startPos = $opener;

		do {
			$hasAssignment = $this->phpcsFile->findNext( $this->assignment_tokens, ( $startPos + 1 ), $closer );
			if ( false === $hasAssignment ) {
				return;
			}

			// Examine whether the left side is a variable.
			$hasVariable       = false;
			$conditionStart    = $startPos;
			$altConditionStart = $this->phpcsFile->findPrevious(
				$this->condition_start_tokens,
				( $hasAssignment - 1 ),
				$startPos
			);
			if ( false !== $altConditionStart ) {
				$conditionStart = $altConditionStart;
			}

			for ( $i = $hasAssignment; $i > $conditionStart; $i-- ) {
				if ( isset( Tokens::$emptyTokens[ $this->tokens[ $i ]['code'] ] ) ) {
					continue;
				}

				// If this is a variable or array, we've seen all we need to see.
				if ( \T_VARIABLE === $this->tokens[ $i ]['code']
					|| \T_CLOSE_SQUARE_BRACKET === $this->tokens[ $i ]['code']
				) {
					$hasVariable = true;
					break;
				}

				// If this is a function call or something, we are OK.
				if ( \T_CLOSE_PARENTHESIS === $this->tokens[ $i ]['code'] ) {
					break;
				}
			}

			if ( true === $hasVariable ) {
				$this->phpcsFile->addWarning(
					'Variable assignment found within a condition. Did you mean to do a comparison?',
					$hasAssignment,
					'FoundInTernaryCondition'
				);
			}

			$startPos = $hasAssignment;

		} while ( $startPos < $closer );
	}
}