<?php
/**
 * SCSSPHP
 *
 * @copyright 2012-2020 Leaf Corcoran
 *
 * @license http://opensource.org/licenses/MIT MIT
 *
 * @link http://scssphp.github.io/scssphp
 */

namespace ScssPhp\ScssPhp;

use ScssPhp\ScssPhp\Formatter\OutputBlock;
use ScssPhp\ScssPhp\SourceMap\SourceMapGenerator;

/**
 * Base formatter
 *
 * @author Leaf Corcoran <leafot@gmail.com>
 */
abstract class Formatter {

	/**
	 * @var integer
	 */
	public $indentLevel;

	/**
	 * @var string
	 */
	public $indentChar;

	/**
	 * @var string
	 */
	public $break;

	/**
	 * @var string
	 */
	public $open;

	/**
	 * @var string
	 */
	public $close;

	/**
	 * @var string
	 */
	public $tagSeparator;

	/**
	 * @var string
	 */
	public $assignSeparator;

	/**
	 * @var boolean
	 */
	public $keepSemicolons;

	/**
	 * @var \ScssPhp\ScssPhp\Formatter\OutputBlock
	 */
	protected $currentBlock;

	/**
	 * @var integer
	 */
	protected $currentLine;

	/**
	 * @var integer
	 */
	protected $currentColumn;

	/**
	 * @var \ScssPhp\ScssPhp\SourceMap\SourceMapGenerator
	 */
	protected $sourceMapGenerator;

	/**
	 * @var string
	 */
	protected $strippedSemicolon;

	/**
	 * Initialize formatter
	 *
	 * @api
	 */
	abstract public function __construct();

	/**
	 * Return indentation (whitespace)
	 *
	 * @return string
	 */
	protected function indentStr() {
		return '';
	}

	/**
	 * Return property assignment
	 *
	 * @api
	 *
	 * @param string $name
	 * @param mixed  $value
	 *
	 * @return string
	 */
	public function property( $name, $value ) {
		return rtrim( $name ) . $this->assignSeparator . $value . ';';
	}

	/**
	 * Return custom property assignment
	 * differs in that you have to keep spaces in the value as is
	 *
	 * @api
	 *
	 * @param string $name
	 * @param mixed  $value
	 *
	 * @return string
	 */
	public function customProperty( $name, $value ) {
		return rtrim( $name ) . trim( $this->assignSeparator ) . $value . ';';
	}

	/**
	 * Output lines inside a block
	 *
	 * @param \ScssPhp\ScssPhp\Formatter\OutputBlock $block
	 */
	protected function blockLines( OutputBlock $block ) {
		$inner = $this->indentStr();
		$glue  = $this->break . $inner;

		$this->write( $inner . implode( $glue, $block->lines ) );

		if ( ! empty( $block->children ) ) {
			$this->write( $this->break );
		}
	}

	/**
	 * Output block selectors
	 *
	 * @param \ScssPhp\ScssPhp\Formatter\OutputBlock $block
	 */
	protected function blockSelectors( OutputBlock $block ) {
		$inner = $this->indentStr();

		$this->write(
			$inner
			. implode( $this->tagSeparator, $block->selectors )
			. $this->open . $this->break
		);
	}

	/**
	 * Output block children
	 *
	 * @param \ScssPhp\ScssPhp\Formatter\OutputBlock $block
	 */
	protected function blockChildren( OutputBlock $block ) {
		foreach ( $block->children as $child ) {
			$this->block( $child );
		}
	}

	/**
	 * Output non-empty block
	 *
	 * @param \ScssPhp\ScssPhp\Formatter\OutputBlock $block
	 */
	protected function block( OutputBlock $block ) {
		if ( empty( $block->lines ) && empty( $block->children ) ) {
			return;
		}

		$this->currentBlock = $block;

		$pre = $this->indentStr();

		if ( ! empty( $block->selectors ) ) {
			$this->blockSelectors( $block );

			$this->indentLevel++;
		}

		if ( ! empty( $block->lines ) ) {
			$this->blockLines( $block );
		}

		if ( ! empty( $block->children ) ) {
			$this->blockChildren( $block );
		}

		if ( ! empty( $block->selectors ) ) {
			$this->indentLevel--;

			if ( ! $this->keepSemicolons ) {
				$this->strippedSemicolon = '';
			}

			if ( empty( $block->children ) ) {
				$this->write( $this->break );
			}

			$this->write( $pre . $this->close . $this->break );
		}
	}

	/**
	 * Test and clean safely empty children
	 *
	 * @param \ScssPhp\ScssPhp\Formatter\OutputBlock $block
	 *
	 * @return boolean
	 */
	protected function testEmptyChildren( $block ) {
		$isEmpty = empty( $block->lines );

		if ( $block->children ) {
			foreach ( $block->children as $k => &$child ) {
				if ( ! $this->testEmptyChildren( $child ) ) {
					$isEmpty = false;
					continue;
				}

				if ( $child->type === Type::T_MEDIA || $child->type === Type::T_DIRECTIVE ) {
					$child->children  = array();
					$child->selectors = null;
				}
			}
		}

		return $isEmpty;
	}

	/**
	 * Entry point to formatting a block
	 *
	 * @api
	 *
	 * @param \ScssPhp\ScssPhp\Formatter\OutputBlock             $block              An abstract syntax tree
	 * @param \ScssPhp\ScssPhp\SourceMap\SourceMapGenerator|null $sourceMapGenerator Optional source map generator
	 *
	 * @return string
	 */
	public function format( OutputBlock $block, SourceMapGenerator $sourceMapGenerator = null ) {
		$this->sourceMapGenerator = null;

		if ( $sourceMapGenerator ) {
			$this->currentLine        = 1;
			$this->currentColumn      = 0;
			$this->sourceMapGenerator = $sourceMapGenerator;
		}

		$this->testEmptyChildren( $block );

		ob_start();

		$this->block( $block );

		$out = ob_get_clean();

		return $out;
	}

	/**
	 * Output content
	 *
	 * @param string $str
	 */
	protected function write( $str ) {
		if ( ! empty( $this->strippedSemicolon ) ) {
			echo alpha_escaped( $this->strippedSemicolon );

			$this->strippedSemicolon = '';
		}

		/*
		 * Maybe Strip semi-colon appended by property(); it's a separator, not a terminator
		 * will be striped for real before a closing, otherwise displayed unchanged starting the next write
		 */
		if ( ! $this->keepSemicolons &&
			$str &&
			( strpos( $str, ';' ) !== false ) &&
			( substr( $str, -1 ) === ';' )
		) {
			$str = substr( $str, 0, -1 );

			$this->strippedSemicolon = ';';
		}

		if ( $this->sourceMapGenerator ) {
			$this->sourceMapGenerator->addMapping(
				$this->currentLine,
				$this->currentColumn,
				$this->currentBlock->sourceLine,
				//columns from parser are off by one
				$this->currentBlock->sourceColumn > 0 ? $this->currentBlock->sourceColumn - 1 : 0,
				$this->currentBlock->sourceName
			);

			$lines              = explode( "\n", $str );
			$lineCount          = \count( $lines );
			$this->currentLine += $lineCount - 1;

			$lastLine = array_pop( $lines );

			$this->currentColumn = ( $lineCount === 1 ? $this->currentColumn : 0 ) + \strlen( $lastLine );
		}

		echo alpha_escaped( $str );
	}
}