<?php

/**
 * Helper, manage lines when processing Markdown.
 */
namespace markdown;

use sys\arr;

class lines
{
  /**
   * Inputed lines.
   */
  protected $in = [];

  /**
   * Processed lines.
   */
  protected $lines = [];

  /**
   * Instance of lines.
   * --
   * @param array $lines Raw input of Markdown lines.
   */
  function __construct(array $lines=[])
  {
    $this->in = $lines;
    $this->reset();
  }

  /**
   * Return all processed lines.
   * --
   * @return array
   */
  function get_all()
  {
    return $this->lines;
  }

  /**
   * Get line's tag(s) at particular position.
   * --
   * @param integer $at
   * --
   * @return array
   *         [ array $open_tags, string $line, array $close_tags, array $attributes ]
   */
  function get_raw($at)
  {
    if (isset($this->lines[$at]))
    {
      return $this->lines[$at];
    }
    else
    {
      return [ [], null, [], [] ];
    }
  }

  /**
   * Reset processed lines (to be the same as when object was constructed).
   * If $at provided, reset only particular line.
   * --
   * @param integer $at
   */
  function reset($at=null)
  {
    if ($at !== null)
    {
      if ($this->has($at))
      {
        $this->lines[$at] = [
          [], $this->in[$at], [], []
        ];
      }
    }
    else
    {
      $this->lines = [];

      // Reset live & empty output
      foreach ($this->in as $lineno => $line)
      {
        $this->lines[$lineno] = [
          // Open tags
          [],
          // Current line
          $line,
          // Close tags
          [],
          // Attributes
          []
        ];
      }
    }

  }

  /**
   * Get number of all lines.
   * --
   * @return integer
   */
  function count()
  {
    return count($this->in);
  }

  /**
   * Set line at particular position.
   * This allows you to set line's content and tag(s).
   * --
   * @param integer $at
   *        Positon where to set.
   *
   * @param string $line
   *        Line's content.
   *
   * @param mixed $tags
   *        Either:
   *        array  [string $open, string $close]
   *        string Both tags
   */
  function set($at, $line, $tags=null)
  {
    if (isset($this->lines[$at]))
    {
      // Line itself
      $this->lines[$at][1] = $line;

      if ($tags)
      {
        $this->set_tag($at, $tags);
      }
    }
    else
    {
      err('set_non_existent_line', "At `{$at}` to `{$line}`");
    }
  }

  /**
   * Get line at particular position.
   * This will return only line without tags. See $this->get_raw() to get
   * full array (with attributes, etc...) for a line.
   * --
   * @param integer $at
   * --
   * @return sting
   */
  function get($at, $trim=false)
  {
    if (isset($this->lines[$at]))
    {
      return $this->lines[$at][1];
    }
    else
    {
      return null;
    }
  }

  /**
   * There's no content on this line.
   * --
   * @param integer $at
   * @param boolean $trim Weather to trim line before checking.
   * --
   * @return boolean
   */
  function is_empty($at, $trim=false)
  {
    $line = $this->get($at);
    return !($trim ? trim($line) : $line);
  }

  /**
   * Does line exists at particulat position.
   * --
   * @param integer $at
   * --
   * @return boolean
   */
  function has($at)
  {
    return isset($this->lines[$at]);
  }

  /**
   * Erase line at particular position.
   * --
   * @param integer $at
   * @param boolean $fully Wipe all tags on the line too.
   */
  function erase($at, $fully=false)
  {
    if (isset($this->lines[$at]))
    {
      if ($fully)
      {
        $this->lines[$at] = [
          [], '', [], []
        ];
      }
      else
      {
        $this->lines[$at][1] = '';
      }
    }
  }

  /**
   * Get line's attribute.
   * --
   * @param string $at
   * @param string $attr
   * @param mixed  $default
   * --
   * @return mixed
   */
  function get_attr($at, $attr, $default=null)
  {
    if (isset($this->lines[$at]) && isset($this->lines[$at][3][$attr]))
    {
      return $this->lines[$at][3][$attr];
    }
    else
    {
      return $default;
    }
  }

  /**
   * Set attribute for a line.
   * --
   * @param integer $at
   * @param mixed   $attr  string one value | array multiple
   * @param mixed   $value
   */
  function set_attr($at, $attr, $value=null)
  {
    if (isset($this->lines[$at]))
    {
      if (is_array($attr))
      {
        foreach ($attr as $attr_k => $attr_v)
        {
          $this->lines[$at][3][$attr_k] = $attr_v;
        }
      }
      else
      {
        $this->lines[$at][3][$attr] = $value;
      }
    }
    else
    {
      if (is_array($attr)) $attr = implode(',', array_keys($attr));
      err('attr_on_non_existent_line', "Line `{$attr}` at `{$at}`");
    }
  }

  /**
   * Set line's tag(s) at particular position.
   * --
   * @param integer $at
   *
   * @param mixed $tags
   *        `array [string $open, string $close]` | `string both`
   *
   * @param boolean $close_prepend
   *        Prepend closed tag, rather than append.
   *        This will make sense in most cases when setting both tags.
   */
  function set_tag($at, $tags=null, $close_prepend=true)
  {
    if (isset($this->lines[$at]))
    {
      // Both the same
      if ($tags)
      {
        if (!is_array($tags))
        {
          $tags = [$tags, $tags];
        }

        // Open tag
        if (isset($tags[0]) && $tags[0])
        {
          $this->lines[$at][0][] = $tags[0];
        }

        // Close tag
        if (isset($tags[1]) && $tags[1])
        {
          if ($close_prepend)
          {
            array_unshift($this->lines[$at][2], $tags[1]);
          }
          else
          {
            $this->lines[$at][2][] = $tags[1];
          }
        }
      }
    }
    else
    {
      err('tag_on_non_existent_line', "Line: ".print_r($tags, true)."` at `{$at}`");
    }
  }

  /**
   * Move tags from one line to another (this will erase tags in $from and
   * move them $to). Tags will be appened to $to.
   * --
   * @param  integer $from
   * @param  integer $to
   * @param  array  $target [ open, close ]
   */
  function move_tags($from, $to, array $target)
  {
    if (!$this->has($from)) err('source_not_found', $from);
    if (!$this->has($to)) err('target_not_found', $to);

    $this->lines[$to][2] = array_merge(
      $this->lines[$to][2],
      $this->lines[$from][2]
    );

    $this->lines[$from][2] = [];
  }

  /**
   * Get one tag at particular line, at particular position.
   * --
   * @param integer $at
   *        Tag at which Line.
   *
   * @param integer $from
   *        Position, which can be negative, for example:
   *        -1 to get last tag in the list.
   *
   * @param string $type
   *        Either null (open tag) or '/' to query close tag.
   * --
   * @return string
   */
  function get_tag($at, $from, $type=null)
  {
    list($o, $c) = $this->get_tags($at);
    $pool = $type ? $c : $o;
    $pool = array_slice($pool, $from, 1);

    return isset($pool[0]) ? $pool[0] : null;
  }

  /**
   * Get tag(s) for particular line.
   * --
   * @param integer $at
   * --
   * @return array [ array open, array close ]
   */
  function get_tags($at)
  {
    list($o, $_, $c, $_) = $this->get_raw($at);
    return [$o, $c];
  }

  /**
   * See if open (or close) tag exists at particular line.
   * --
   * @param integer $at
   *
   * @param string $tag
   *        `null` opened tags
   *        `tag`  particular opened tag,
   *        `/`    closed tags
   *        `/tag` particular close tag
   * --
   * @return boolean
   */
  function has_tag($at, $tag=null)
  {
    list($open, $_, $close) = $this->get_raw($at);
    $pool = substr($tag, 0, 1) === '/' ? $close : $open;
    $tag = trim($tag, '/');

    return $tag ? (array_search($tag, $pool) !== false) : !!count($pool);
  }

  /**
   * Erase particular tag(s).
   * --
   * @param integer $at
   * @param string  $tag   Tag name, use /tag to target close tags.
   * @param integer $count How many to erase.
   */
  function erase_tag($at, $tag, $count)
  {
    $is_close = substr($tag, 0, 1) === '/';
    $pool = !$is_close ? 0 : 2;
    $pool = &$this->lines[$at][$pool];
    $tag = trim($tag, '/');

    for ($i=count($pool)-1; $i >= 0; $i--)
    {
      if ($pool[$i] === $tag)
      {
        unset($pool[$i]);
        $count--;
      }

      if ($count === 0)
      {
        break;
      }
    }

    $pool = array_values($pool);
  }

  /**
   * Get number of open and closed tags at position.
   * --
   * @param integer $at
   *
   * @param string $tag
   *        If you don't provide a tag,
   *        it will return sum count of all tags at this line.
   * --
   * @return array `[integer $open, integer $close]`
   */
  function count_tag($at, $tag=null)
  {
    list($open, $_, $close) = $this->get_raw($at);
    return [
      $tag ? arr::count_values_of($open, $tag) : count($open),
      $tag ? arr::count_values_of($close, $tag) : count($close)
    ];
  }

  /**
   * Output lines for debuging, flat array format.
   * --
   * @return array
   */
  function debug_flat_array()
  {
    $array = [];

    foreach ($this->get_all() as $line)
    {
      $array[] = implode(',', $line[0])  . ' ' .$line[1] . ' ' . implode(',', $line[2]);
    }

    return $array;
  }
}