<?php

namespace ImportWP\Common\Importer\File;

use ImportWP\Common\Importer\FileInterface;
use ImportWP\Common\Importer\State\ImporterState;

class XMLFile extends AbstractIndexedFile implements FileInterface
{

    /**
     * Base path
     * 
     * Name of the files base path node, added onto the end of base_path_segments.
     * e.g. if record path is 'records/record', base_path would be 'record'.
     *
     * @var string
     */
    protected $base_path;

    /**
     * Base path segments
     * 
     * Stores a list of nodes up to and not including the final base_path
     * e.g. if base_path is 'records/record' , base_path_node would be ['records']
     *
     * @var string[]
     */
    protected $base_path_segments = array();

    /**
     * Open nodes
     * 
     * List of nodes that have not been opened so far while parsing the file.
     *
     * @var string[]
     */
    protected $open_nodes = array();

    protected $record_offset = 0;
    protected $chunk_size = 8192;
    protected $depth = 0;
    protected $node_list = array();
    protected $namespace_list = null;
    protected $chunk;
    protected $chunk_offset = 0;

    protected $record_counter = 0;
    protected $record_start_index = 0;

    /**
     * Record Opened
     * 
     * Flag to say we are parsing data within the chosen record path.
     *
     * @var boolean
     */
    protected $record_opened = false;
    protected $last_record_incomplete = false;
    protected $record_patch_cache_key = '';

    /**
     * Set base path for records
     *
     * @param string $base_path
     */
    public function setRecordPath($base_path = '/')
    {
        // strip slash from start
        if (strpos($base_path, '/') === 0) {
            $base_path = substr($base_path, 1);
        }

        // split basepath in segments
        $this->base_path_segments = explode('/', $base_path);
        array_filter($this->base_path_segments, function ($value) {
            return $value !== "";
        });

        if (!empty($this->base_path_segments)) {
            $this->record_patch_cache_key = implode('_', $this->base_path_segments);
            $base_path                    = array_pop($this->base_path_segments);
        }

        $this->base_path = $base_path;
    }

    /**
     * Get record
     *
     * @param int $index
     *
     * @return string
     */
    public function getRecord($index = 0)
    {
        $record = parent::getRecord($index);

        if ($index === $this->getRecordCount() - 1 && true === $this->last_record_incomplete) {
            $record = $this->fixRecord($record);
        }

        return $this->wrapWithRecordTag($record);
    }

    /**
     * Fix a broken xml segment
     *
     * @param $record
     *
     * @return bool|string
     */
    public function fixRecord($record)
    {
        $open       = "/<[^\/][^>]+[^\/]>/";
        $close      = "/<\/[^>]+[^\/]>/";
        $depth      = 0;
        $started    = false;
        $open_nodes = array();

        $chunk = $record;

        while (preg_match(
            "/<[^?|!\-\-][^>]*>/",
            $chunk,
            $matches,
            PREG_OFFSET_CAPTURE
        ) !== 0) {
            if (isset($matches[0]) && isset($matches[0][0])) {
                list($captured, $offset) = $matches[0];

                if (preg_match($open, $captured) === 1) {
                    $started = true;
                    $depth++;
                    $node_name    = $this->getNodeName($captured);
                    $open_nodes[] = $node_name;
                } else if (preg_match($close, $captured) === 1) {
                    $depth--;
                    array_pop($open_nodes);
                }

                $string_offset = $offset + strlen($captured);
                $chunk         = substr($chunk, $string_offset);
            }

            if ($started && 0 === $depth) {
                // We should be at the end of the xml
                return substr($record, 0, strlen($chunk));
            }
        }

        if (!empty($open_nodes)) {
            // Add closing tags for open nodes
            foreach ($open_nodes as $node) {
                $record .= "</{$node}>";
            }
        }

        return $record;
    }

    /**
     * Get node name from xml tag
     *
     * @param $node
     *
     * @return bool|string
     */
    public function getNodeName($node)
    {

        preg_match("/<\/?([a-zA-Z0-9\-_\.:]+)[ ]*[^>]*>/", $node, $matches);
        if (isset($matches[0]) && isset($matches[1])) {
            $name = $matches[1];
        } else {
            $name = substr($node, 1, strlen($node) - 2);
        }

        return $name;
    }

    /**
     * Generate file position index.
     *
     * Read through entire xml file generating record start and end positions
     *
     * @return mixed
     */
    public function generateIndex()
    {
        $this->record_counter     = 0;
        $this->record_start_index = 0;

        $last_percent = 0;
        $size = intval($this->get_file_size($this->getFileHandle()));
        $this->config->set('process', 0);
        $this->namespace_list = [];

        rewind($this->getFileHandle());

        while (!feof($this->getFileHandle())) {

            $this->chunk .= $this->getChunk();
            $this->chunk = $this->read_chunk_xml_nodes($this->chunk);

            // only read the first 1mb of file
            if ($this->is_processing && ($this->record_counter > 0 || ftell($this->getFileHandle()) > $this->process_max_size)) {
                break;
            }

            $current_pos = intval(ftell($this->getFileHandle()));
            if ($size > 0 && $current_pos > 0) {
                $percent = round($current_pos / $size, 2);
                if ($percent > $last_percent) {

                    do_action('iwp/importer/process', $last_percent * 100);
                    $this->config->set('process', $last_percent * 100);
                    $last_percent = $percent;

                    if (!is_null(iwp()->importer)) {
                        $state = ImporterState::get_state(iwp()->importer->getId());
                        if (isset($state['status']) && $state['status'] === 'cancelled') {
                            return;
                        }
                    }
                }
            }
        }

        $this->config->set('namespace_list', $this->namespace_list);

        // if file is incomplete do we try and fix the record, or skip it?
        if (!$this->is_processing && true === $this->record_opened) {
            $this->record_opened          = false;
            $this->last_record_incomplete = true;
            $this->setIndex(
                $this->record_counter,
                $this->record_start_index,
                $this->chunk_offset
            );
        }
    }

    /**
     * Read chunk from file
     *
     * @return bool|string
     */
    public function getChunk()
    {
        return fread($this->getFileHandle(), $this->chunk_size);
    }

    /**
     * Read all xml nodes in chunk
     */
    public function readChunkXmlNodes()
    {
        $tags = [
            ["<?", "?>", true, 0],
            ["<!--", "-->", true, 0],
            ["<![CDATA[", "]]>", true, 0],
            ["<!", ">", true, 0],
            ["</", ">", false, -1],
            ["<", "/>", false, 0],
            ["<", ">", false, 1],
        ];

        while (preg_match("/<[^>]+>/", $this->chunk, $matches, PREG_OFFSET_CAPTURE) !== 0) {
            list($captured, $offset) = $matches[0];

            $this->record_offset = $offset;

            foreach ($tags as $tag) {

                list($open_tag, $close_tag, $search_for_close, $depth_delta) = $tag;

                if (strpos($captured, $open_tag) === 0) {

                    if (strlen($captured) - strlen($close_tag) === strpos($captured, $close_tag)) {
                        // Tag Found
                        if ($search_for_close === false) {
                            $this->record_node($captured, $depth_delta);
                        }
                        break;
                    } elseif ($search_for_close === true) {
                        $close_tag_position = strpos($this->chunk, $close_tag, $offset);
                        if ($close_tag_position !== false) {
                            // Close tag is found in current chunk
                            $captured = substr($this->chunk, $offset, $close_tag_position + strlen($close_tag) - $offset);
                            if ($search_for_close === false) {
                                $this->record_node($captured, $depth_delta);
                            }
                        } else {
                            // We need to load next chunk to find
                            return;
                        }
                        break;
                    }
                }
            }

            $string_offset      = $offset + strlen($captured);
            $this->chunk_offset += $string_offset;
            $this->chunk        = substr($this->chunk, $string_offset);
        }
    }

    /**
     * Optimised version of readChunkXMLNodes
     *
     * @param string $chunk
     * @return string
     */
    public function read_chunk_xml_nodes($chunk)
    {
        $tags = [
            "<?" => ["<?", "?>", true, 0],
            "<!--" => ["<!--", "-->", true, 0],
            "<![CDATA[" => ["<![CDATA[", "]]>", true, 0],
            "<!" => ["<!", ">", true, 0],
            "</" => ["</", ">", false, -1],
            "<" => ["<", "/>", false, 0],
            "<" => ["<", ">", false, 1],
        ];

        // 1.Loop through the file, each node at a time
        $chunk_offset = 0;

        while (preg_match("/<[^>]+>/", $chunk, $matches, PREG_OFFSET_CAPTURE, $chunk_offset) !== 0) {
            list($captured, $offset) = $matches[0];

            // length of content between last and current tag
            $content_length = ($offset - $chunk_offset);
            $chunk_offset += $content_length + strlen($captured);

            if (preg_match('/^(<\?|<!--|<!\[CDATA\[|<!|<\/|<)/', $captured, $tag_matches) !== 1) {
                continue;
            }

            $tags_test = [];
            if ($tag_matches[0] === '<') {
                $tags_test[] = ["<", "/>", false, 0];
                $tags_test[] = ["<", ">", false, 1];
            } else {
                $tags_test[] = $tags[$tag_matches[0]];
            }

            // print_r($tag_matches);

            foreach ($tags_test as $tag) {
                list($open_tag, $close_tag, $search_for_close, $depth_delta) = $tag;

                // if (strpos($captured, $open_tag) !== 0) {
                //     continue;
                // }

                if (strlen($captured) - strlen($close_tag) === strpos($captured, $close_tag)) {
                    // Tag Found
                    if ($search_for_close === false) {
                        $this->record_node($captured, $depth_delta, $this->chunk_offset + $offset);
                    }
                    break;
                } elseif ($search_for_close === true) {
                    $close_tag_position = strpos($chunk, $close_tag, $offset);
                    if ($close_tag_position !== false) {
                        // Close tag is found in current chunk
                        $captured = substr($chunk, $offset, $close_tag_position + strlen($close_tag) - $offset);
                        $chunk_offset = $close_tag_position + strlen($close_tag);
                        if ($search_for_close === false) {
                            $this->record_node($captured, $depth_delta, $this->chunk_offset + $offset);
                        }
                    } else {
                        // We need to load next chunk to find
                        $this->chunk_offset += $offset;
                        return substr($chunk, $offset);
                    }
                    break;
                }
            }
        }

        $this->chunk_offset += $chunk_offset;

        return substr($chunk, $chunk_offset);
    }

    public function record_node($node, $depth_delta, $offset = null)
    {
        if (is_null($offset)) {
            $offset = $this->chunk_offset + $this->record_offset;
        }

        $this->depth += $depth_delta;
        $node_name = $this->getNodeName($node);

        if ($depth_delta > 0) {

            if ($this->isRecordStart($node_name)) {
                $this->record_opened = true;
                $this->record_start_index = $offset;
            }

            $this->open_nodes[] = $node_name;
            $this->record_open_nodes();

            // find namespaces
            if (preg_match_all('/xmlns:([a-zA-Z0-9_-]+)="([^"]+)"/', $node, $matches) > 0) {
                $this->namespace_list = array_merge($this->namespace_list, array_combine($matches[1], $matches[2]));
            }
        } elseif ($depth_delta < 0) {

            array_pop($this->open_nodes);
            if ($this->isRecordEnd($node_name)) {
                $this->record_opened = false;

                $this->setIndex(
                    $this->record_counter,
                    $this->record_start_index,
                    $offset + strlen($node)
                );
                $this->record_counter++;
            }
        }
    }

    /**
     * Check for record start node
     *
     * @param $node_name
     *
     * @return bool
     */
    public function isRecordStart($node_name)
    {

        if ($this->base_path_segments === $this->open_nodes && $node_name === $this->base_path) {
            return true;
        }

        return false;
    }

    /**
     * Check for record end node
     *
     * @param $node_name
     *
     * @return bool
     */
    public function isRecordEnd($node_name)
    {
        if ($this->record_opened === false) {
            return false;
        }

        if ($this->base_path_segments !== $this->open_nodes) {
            return false;
        }

        if ($node_name !== $this->base_path) {
            return false;
        }

        return true;
    }

    public function wrapWithRecordTag($record)
    {
        $namespace_attrs = '';
        $unique_matches = array();

        // clear sub namespaces
        $record = preg_replace('/xmlns[^=]*="[^"]*"/i', '', $record);

        // No need to check within cdata tags
        $temp = preg_replace('/<!\[CDATA\[((?:[^]]|\](?!\]>))*)\]\]>/', '', $record);

        //        $new_regex       = '/<([^:!\/]+):[^ ]+[^>]*>/';
        //        $new_regex = '/<([^!\/>]+):[^>]+>/'; // breaking due to attr="http://", would match the :
        $new_regex = '/<([^!\/">]+):[^>]+>/';

        while (preg_match($new_regex, $temp, $matches, PREG_OFFSET_CAPTURE) !== 0) {
            if (isset($matches[0]) && isset($matches[0][0]) && isset($matches[1]) && isset($matches[1][0])) {
                list($match, $offset) = $matches[0];
                $namespace = trim($matches[1][0]);

                // TODO: update regex to not need this
                $namespace_parts = explode(' ', $namespace);
                $namespace = $namespace_parts[count($namespace_parts) - 1];

                if (!in_array($namespace, $unique_matches)) {
                    $unique_matches[] = $namespace;

                    // load namespace list if needed
                    if (is_null($this->namespace_list) && !is_null($this->config)) {
                        $this->namespace_list = $this->config->get('namespace_list');
                        if (!is_array($this->namespace_list)) {
                            $this->namespace_list = array();
                        }
                    }

                    if (isset($this->namespace_list[$namespace])) {
                        $namespace_attrs .= ' xmlns:' . $namespace . '="' . $this->namespace_list[$namespace] . '"';
                    } else {
                        $namespace_attrs .= ' xmlns:' . $namespace . '="false"';
                    }
                }

                $temp = substr($temp, $offset + strlen($match));
            }
        }

        $open_tag = '<record' . $namespace_attrs . '>';
        $close_tag = '</record>';
        return $open_tag . $record . $close_tag;
    }

    public function record_open_nodes()
    {
        $key = '/' . implode('/', $this->open_nodes);
        if (!in_array($key, $this->node_list, true)) {
            array_push($this->node_list, $key);
        }
    }

    public function get_node_list()
    {

        $this->node_list = $this->config->get('node_list');
        if (!is_array($this->node_list)) {
            $this->node_list = array();
        }

        $loaded = $this->loadIndex();
        if (empty($this->node_list) || !$loaded) {
            $this->generateIndex();
            $this->storeIndexes();

            $this->config->set('node_list', $this->node_list);
        }

        return $this->node_list;
    }

    public final function getFileIndexKey()
    {
        $key = sprintf('file_index-%s', $this->record_patch_cache_key);

        return $key;
    }
}