/*
  Copyright(C) 2009-2018  Brazil
  Copyright(C) 2020  Sutou Kouhei <kou@clear-code.com>

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License version 2.1 as published by the Free Software Foundation.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
*/

#include "../grn_proc.h"
#include "../grn_expr.h"

#include <groonga/plugin.h>
#include <string.h>

#define GRN_FUNC_HIGHLIGHT_HTML_CACHE_NAME    "$highlight_html"

static void
grn_pat_tag_keys_put_original_text(grn_ctx *ctx, grn_obj *output,
                                   const char *text, unsigned int length,
                                   grn_bool use_html_escape)
{
  if (use_html_escape) {
    grn_text_escape_xml(ctx, output, text, length);
  } else {
    GRN_TEXT_PUT(ctx, output, text, length);
  }
}

static grn_rc
grn_pat_tag_keys(grn_ctx *ctx, grn_obj *keywords,
                 const char *string, unsigned int string_length,
                 const char **open_tags, unsigned int *open_tag_lengths,
                 const char **close_tags, unsigned int *close_tag_lengths,
                 unsigned int n_tags,
                 grn_obj *highlighted,
                 grn_bool use_html_escape)
{
  while (string_length > 0) {
#define MAX_N_HITS 16
    grn_pat_scan_hit hits[MAX_N_HITS];
    const char *rest;
    unsigned int i, n_hits;
    unsigned int previous = 0;
    size_t chunk_length;

    n_hits = grn_pat_scan(ctx, (grn_pat *)keywords,
                          string, string_length,
                          hits, MAX_N_HITS, &rest);
    for (i = 0; i < n_hits; i++) {
      unsigned int nth_tag;
      if (hits[i].offset - previous > 0) {
        grn_pat_tag_keys_put_original_text(ctx,
                                           highlighted,
                                           string + previous,
                                           hits[i].offset - previous,
                                           use_html_escape);
      }
      nth_tag = ((hits[i].id - 1) % n_tags);
      GRN_TEXT_PUT(ctx, highlighted,
                   open_tags[nth_tag], open_tag_lengths[nth_tag]);
      grn_pat_tag_keys_put_original_text(ctx,
                                         highlighted,
                                         string + hits[i].offset,
                                         hits[i].length,
                                         use_html_escape);
      GRN_TEXT_PUT(ctx, highlighted,
                   close_tags[nth_tag], close_tag_lengths[nth_tag]);
      previous = hits[i].offset + hits[i].length;
    }

    chunk_length = rest - string;
    if (chunk_length - previous > 0) {
      grn_pat_tag_keys_put_original_text(ctx,
                                         highlighted,
                                         string + previous,
                                         string_length - previous,
                                         use_html_escape);
    }
    string_length -= chunk_length;
    string = rest;
#undef MAX_N_HITS
  }

  return GRN_SUCCESS;
}

static grn_obj *
func_highlight_create_keywords_table(grn_ctx *ctx,
                                     grn_user_data *user_data,
                                     const char *normalizer_name,
                                     unsigned int normalizer_name_length)
{
  grn_obj *keywords;

  keywords = grn_table_create(ctx, NULL, 0, NULL,
                              GRN_OBJ_TABLE_PAT_KEY,
                              grn_ctx_at(ctx, GRN_DB_SHORT_TEXT),
                              NULL);

  if (normalizer_name_length > 0) {
    grn_obj normalizer;
    GRN_TEXT_INIT(&normalizer, GRN_OBJ_DO_SHALLOW_COPY);
    GRN_TEXT_SET(ctx, &normalizer, normalizer_name, normalizer_name_length);
    grn_obj_set_info(ctx, keywords, GRN_INFO_NORMALIZER, &normalizer);
    if (ctx->rc != GRN_SUCCESS) {
      grn_obj_unlink(ctx, keywords);
      keywords = NULL;
    }
    GRN_OBJ_FIN(ctx, &normalizer);
  }

  return keywords;
}

static grn_obj *
highlight_keyword_sets(grn_ctx *ctx, grn_user_data *user_data,
                       grn_obj **keyword_set_args, unsigned int n_keyword_args,
                       grn_obj *string, grn_obj *keywords,
                       grn_bool use_html_escape)
{
  grn_obj *highlighted = NULL;
#define KEYWORD_SET_SIZE 3
  {
    unsigned int i;
    unsigned int n_keyword_sets;
    grn_obj open_tags;
    grn_obj open_tag_lengths;
    grn_obj close_tags;
    grn_obj close_tag_lengths;

    n_keyword_sets = n_keyword_args / KEYWORD_SET_SIZE;

    GRN_OBJ_INIT(&open_tags, GRN_BULK, 0, GRN_DB_VOID);
    GRN_OBJ_INIT(&open_tag_lengths, GRN_BULK, 0, GRN_DB_VOID);
    GRN_OBJ_INIT(&close_tags, GRN_BULK, 0, GRN_DB_VOID);
    GRN_OBJ_INIT(&close_tag_lengths, GRN_BULK, 0, GRN_DB_VOID);

    for (i = 0; i < n_keyword_sets; i++) {
      grn_obj *keyword   = keyword_set_args[i * KEYWORD_SET_SIZE + 0];
      grn_obj *open_tag  = keyword_set_args[i * KEYWORD_SET_SIZE + 1];
      grn_obj *close_tag = keyword_set_args[i * KEYWORD_SET_SIZE + 2];

      grn_table_add(ctx, keywords,
                    GRN_TEXT_VALUE(keyword),
                    GRN_TEXT_LEN(keyword),
                    NULL);
      {
        const char *open_tag_content = GRN_TEXT_VALUE(open_tag);
        grn_bulk_write(ctx, &open_tags,
                       (const char *)(&open_tag_content),
                       sizeof(char *));
      }
      {
        unsigned int open_tag_length = GRN_TEXT_LEN(open_tag);
        grn_bulk_write(ctx, &open_tag_lengths,
                       (const char *)(&open_tag_length),
                       sizeof(unsigned int));
      }
      {
        const char *close_tag_content = GRN_TEXT_VALUE(close_tag);
        grn_bulk_write(ctx, &close_tags,
                       (const char *)(&close_tag_content),
                       sizeof(char *));
      }
      {
        unsigned int close_tag_length = GRN_TEXT_LEN(close_tag);
        grn_bulk_write(ctx, &close_tag_lengths,
                       (const char *)(&close_tag_length),
                       sizeof(unsigned int));
      }
    }

    highlighted = grn_plugin_proc_alloc(ctx, user_data, GRN_DB_TEXT, 0);
    grn_pat_tag_keys(ctx, keywords,
                     GRN_TEXT_VALUE(string), GRN_TEXT_LEN(string),
                     (const char **)GRN_BULK_HEAD(&open_tags),
                     (unsigned int *)GRN_BULK_HEAD(&open_tag_lengths),
                     (const char **)GRN_BULK_HEAD(&close_tags),
                     (unsigned int *)GRN_BULK_HEAD(&close_tag_lengths),
                     n_keyword_sets,
                     highlighted,
                     use_html_escape);
    grn_obj_unlink(ctx, &open_tags);
    grn_obj_unlink(ctx, &open_tag_lengths);
    grn_obj_unlink(ctx, &close_tags);
    grn_obj_unlink(ctx, &close_tag_lengths);
  }
#undef KEYWORD_SET_SIZE
  return highlighted;
}

static grn_obj *
highlight_keywords(grn_ctx *ctx, grn_user_data *user_data,
                   grn_obj *string, grn_obj *keywords, grn_bool use_html_escape,
                   const char *default_open_tag, unsigned int default_open_tag_length,
                   const char *default_close_tag, unsigned int default_close_tag_length)
{
  grn_obj *highlighted = NULL;
  const char *open_tags[1];
  unsigned int open_tag_lengths[1];
  const char *close_tags[1];
  unsigned int close_tag_lengths[1];
  unsigned int n_keyword_sets = 1;

  open_tags[0] = default_open_tag;
  open_tag_lengths[0] = default_open_tag_length;
  close_tags[0] = default_close_tag;
  close_tag_lengths[0] = default_close_tag_length;

  highlighted = grn_plugin_proc_alloc(ctx, user_data, GRN_DB_TEXT, 0);
  grn_pat_tag_keys(ctx, keywords,
                   GRN_TEXT_VALUE(string), GRN_TEXT_LEN(string),
                   open_tags,
                   open_tag_lengths,
                   close_tags,
                   close_tag_lengths,
                   n_keyword_sets,
                   highlighted,
                   use_html_escape);

  return highlighted;
}

static grn_obj *
func_highlight(grn_ctx *ctx, int nargs, grn_obj **args,
               grn_user_data *user_data)
{
  grn_obj *highlighted = NULL;

#define N_REQUIRED_ARGS 1
  if (nargs > N_REQUIRED_ARGS) {
    grn_obj *string = args[0];
    grn_bool use_html_escape = GRN_FALSE;
    grn_obj *keywords;
    const char *normalizer_name = "NormalizerAuto";
    unsigned int normalizer_name_length = 14;
    const char *default_open_tag = NULL;
    unsigned int default_open_tag_length = 0;
    const char *default_close_tag = NULL;
    unsigned int default_close_tag_length = 0;
    grn_obj *end_arg = args[nargs - 1];
    int n_args_without_option = nargs;

    if (end_arg->header.type == GRN_TABLE_HASH_KEY) {
      grn_obj *options = end_arg;
      grn_hash_cursor *cursor;
      void *key;
      grn_obj *value;
      int key_size;

      n_args_without_option--;
      cursor = grn_hash_cursor_open(ctx, (grn_hash *)options,
                                    NULL, 0, NULL, 0,
                                    0, -1, 0);
      if (!cursor) {
        GRN_PLUGIN_ERROR(ctx, GRN_NO_MEMORY_AVAILABLE,
                         "highlight(): couldn't open cursor");
        goto exit;
      }
      while (grn_hash_cursor_next(ctx, cursor) != GRN_ID_NIL) {
        grn_hash_cursor_get_key_value(ctx, cursor, &key, &key_size,
                                      (void **)&value);
        if (key_size == 10 && !memcmp(key, "normalizer", 10)) {
          normalizer_name = GRN_TEXT_VALUE(value);
          normalizer_name_length = GRN_TEXT_LEN(value);
        } else if (key_size == 11 && !memcmp(key, "html_escape", 11)) {
          if (GRN_BOOL_VALUE(value)) {
            use_html_escape = GRN_TRUE;
          }
        } else if (key_size == 16 && !memcmp(key, "default_open_tag", 16)) {
          default_open_tag = GRN_TEXT_VALUE(value);
          default_open_tag_length = GRN_TEXT_LEN(value);
        } else if (key_size == 17 && !memcmp(key, "default_close_tag", 17)) {
          default_close_tag = GRN_TEXT_VALUE(value);
          default_close_tag_length = GRN_TEXT_LEN(value);
        } else {
          GRN_PLUGIN_ERROR(ctx, GRN_INVALID_ARGUMENT, "invalid option name: <%.*s>",
                           key_size, (char *)key);
          grn_hash_cursor_close(ctx, cursor);
          goto exit;
        }
      }
      grn_hash_cursor_close(ctx, cursor);
    }

    keywords =
      func_highlight_create_keywords_table(ctx, user_data,
                                           normalizer_name,
                                           normalizer_name_length);

    if (keywords) {
      grn_obj **keyword_args = args + N_REQUIRED_ARGS;
      unsigned int n_keyword_args = n_args_without_option - N_REQUIRED_ARGS;
      if (default_open_tag_length == 0 && default_close_tag_length == 0) {
        highlighted = highlight_keyword_sets(ctx, user_data,
                                             keyword_args, n_keyword_args,
                                             string, keywords, use_html_escape);
      } else {
        unsigned int i;
        for (i = 0; i < n_keyword_args; i++) {
          grn_table_add(ctx, keywords,
                        GRN_TEXT_VALUE(keyword_args[i]),
                        GRN_TEXT_LEN(keyword_args[i]),
                        NULL);
        }
        highlighted = highlight_keywords(ctx, user_data,
                                         string, keywords, use_html_escape,
                                         default_open_tag, default_open_tag_length,
                                         default_close_tag, default_close_tag_length);
      }
      grn_obj_unlink(ctx, keywords);
    }
  }
#undef N_REQUIRED_ARGS

exit :
  if (!highlighted) {
    highlighted = grn_plugin_proc_alloc(ctx, user_data, GRN_DB_VOID, 0);
  }

  return highlighted;
}

void
grn_proc_init_highlight(grn_ctx *ctx)
{
  grn_proc_create(ctx, "highlight", -1, GRN_PROC_FUNCTION,
                  func_highlight, NULL, NULL, 0, NULL);
}

static grn_obj *
func_highlight_full(grn_ctx *ctx, int nargs, grn_obj **args,
                    grn_user_data *user_data)
{
  grn_obj *highlighted = NULL;

#define N_REQUIRED_ARGS 3
#define KEYWORD_SET_SIZE 3
  if ((nargs >= (N_REQUIRED_ARGS + KEYWORD_SET_SIZE) &&
      (nargs - N_REQUIRED_ARGS) % KEYWORD_SET_SIZE == 0)) {
    grn_obj *string = args[0];
    grn_obj *keywords;
    const char *normalizer_name = GRN_TEXT_VALUE(args[1]);
    unsigned int normalizer_name_length = GRN_TEXT_LEN(args[1]);
    grn_bool use_html_escape = GRN_BOOL_VALUE(args[2]);

    keywords =
      func_highlight_create_keywords_table(ctx, user_data,
                                           normalizer_name,
                                           normalizer_name_length);
    if (keywords) {
      highlighted = highlight_keyword_sets(ctx, user_data,
                                           args + N_REQUIRED_ARGS,
                                           nargs - N_REQUIRED_ARGS,
                                           string, keywords,
                                           use_html_escape);
      grn_obj_unlink(ctx, keywords);
    }
  }

  if (!highlighted) {
    highlighted = grn_plugin_proc_alloc(ctx, user_data, GRN_DB_VOID, 0);
  }
#undef KEYWORD_SET_SIZE
#undef N_REQUIRED_ARGS

  return highlighted;
}

void
grn_proc_init_highlight_full(grn_ctx *ctx)
{
  grn_proc_create(ctx, "highlight_full", -1, GRN_PROC_FUNCTION,
                  func_highlight_full, NULL, NULL, 0, NULL);
}

static grn_highlighter *
func_highlight_html_create_highlighter(grn_ctx *ctx, grn_obj *expression)
{
  grn_highlighter *highlighter;
  grn_obj *condition = NULL;

  highlighter = grn_highlighter_open(ctx);

  condition = grn_expr_get_condition(ctx, expression);

  for (; condition; condition = grn_expr_get_parent(ctx, condition)) {
    size_t i, n_keywords;
    grn_obj current_keywords;
    GRN_TEXT_INIT(&current_keywords, GRN_OBJ_VECTOR);
    grn_expr_get_keywords(ctx, condition, &current_keywords);

    n_keywords = grn_vector_size(ctx, &current_keywords);
    for (i = 0; i < n_keywords; i++) {
      const char *keyword;
      unsigned int keyword_size;
      keyword_size = grn_vector_get_element(ctx,
                                            &current_keywords,
                                            i,
                                            &keyword,
                                            NULL,
                                            NULL);
      grn_highlighter_add_keyword(ctx,
                                  highlighter,
                                  keyword,
                                  keyword_size);
    }
    GRN_OBJ_FIN(ctx, &current_keywords);
  }

  return highlighter;
}

static grn_obj *
func_highlight_html(grn_ctx *ctx, int nargs, grn_obj **args,
                    grn_user_data *user_data)
{
  grn_obj *highlighted = NULL;
  grn_obj *string;
  grn_obj *lexicon = NULL;
  grn_obj *expression = NULL;
  grn_highlighter *highlighter;
  grn_obj *highlighter_ptr;

  if (!(1 <= nargs && nargs <= 2)) {
    GRN_PLUGIN_ERROR(ctx,
                     GRN_INVALID_ARGUMENT,
                     "highlight_html(): wrong number of arguments (%d for 1..2)",
                     nargs);
    highlighted = grn_plugin_proc_alloc(ctx, user_data, GRN_DB_VOID, 0);
    return highlighted;
  }

  string = args[0];
  if (nargs == 2) {
    lexicon = args[1];
  }

  grn_proc_get_info(ctx, user_data, NULL, NULL, &expression);

  highlighter_ptr = grn_expr_get_var(ctx, expression,
                                     GRN_FUNC_HIGHLIGHT_HTML_CACHE_NAME,
                                     strlen(GRN_FUNC_HIGHLIGHT_HTML_CACHE_NAME));
  if (highlighter_ptr) {
    highlighter = (grn_highlighter *)GRN_PTR_VALUE(highlighter_ptr);
  } else {
    highlighter_ptr =
      grn_expr_get_or_add_var(ctx, expression,
                              GRN_FUNC_HIGHLIGHT_HTML_CACHE_NAME,
                              strlen(GRN_FUNC_HIGHLIGHT_HTML_CACHE_NAME));
    GRN_OBJ_FIN(ctx, highlighter_ptr);
    GRN_PTR_INIT(highlighter_ptr, GRN_OBJ_OWN, GRN_DB_OBJECT);

    highlighter = func_highlight_html_create_highlighter(ctx, expression);
    grn_highlighter_set_lexicon(ctx, highlighter, lexicon);
    GRN_PTR_SET(ctx, highlighter_ptr, highlighter);
  }

  highlighted = grn_plugin_proc_alloc(ctx, user_data, GRN_DB_TEXT, 0);
  grn_highlighter_highlight(ctx,
                            highlighter,
                            GRN_TEXT_VALUE(string),
                            GRN_TEXT_LEN(string),
                            highlighted);

  return highlighted;
}

void
grn_proc_init_highlight_html(grn_ctx *ctx)
{
  grn_proc_create(ctx, "highlight_html", -1, GRN_PROC_FUNCTION,
                  func_highlight_html, NULL, NULL, 0, NULL);
}
