/* ide-snippet.c
 *
 * Copyright 2013-2019 Christian Hergert <christian@hergert.me>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * SPDX-License-Identifier: GPL-3.0-or-later
 */

#define G_LOG_DOMAIN "ide-snippet"

#include "config.h"

#include <dazzle.h>
#include <glib/gi18n.h>

#include "ide-completion-proposal.h"
#include "ide-snippet.h"
#include "ide-snippet-private.h"
#include "ide-snippet-chunk.h"
#include "ide-snippet-context.h"

/**
 * SECTION:ide-snippet
 * @title: IdeSnippet
 * @short_description: A snippet to be inserted into a file
 *
 * The #IdeSnippet represents a single snippet that may be inserted
 * into the #IdeSourceView.
 *
 * Since: 3.32
 */

#define TAG_SNIPPET_TAB_STOP "snippet::tab-stop"

struct _IdeSnippet
{
  GObject                  parent_instance;

  IdeSnippetContext       *snippet_context;
  GtkTextBuffer           *buffer;
  GPtrArray               *chunks;
  GArray                  *runs;
  GtkTextMark             *mark_begin;
  GtkTextMark             *mark_end;
  gchar                   *trigger;
  const gchar             *language;
  gchar                   *description;

  gint                     tab_stop;
  gint                     max_tab_stop;
  gint                     current_chunk;

  guint                    inserted : 1;
};

enum {
  PROP_0,
  PROP_BUFFER,
  PROP_DESCRIPTION,
  PROP_LANGUAGE,
  PROP_MARK_BEGIN,
  PROP_MARK_END,
  PROP_TAB_STOP,
  PROP_TRIGGER,
  LAST_PROP
};

G_DEFINE_FINAL_TYPE (IdeSnippet, ide_snippet, G_TYPE_OBJECT)

DZL_DEFINE_COUNTER (instances, "Snippets", "N Snippets", "Number of IdeSnippet instances.");

static GParamSpec * properties[LAST_PROP];

/**
 * ide_snippet_new:
 * @trigger: (nullable): the trigger word
 * @language: (nullable): the source language
 *
 * Creates a new #IdeSnippet
 *
 * Returns: (transfer full): A new #IdeSnippet
 *
 * Since: 3.32
 */
IdeSnippet *
ide_snippet_new (const gchar *trigger,
                 const gchar *language)
{
  return g_object_new (IDE_TYPE_SNIPPET,
                       "trigger", trigger,
                       "language", language,
                       NULL);
}

/**
 * ide_snippet_copy:
 * @self: an #IdeSnippet
 *
 * Does a deep copy of the snippet.
 *
 * Returns: (transfer full): An #IdeSnippet.
 *
 * Since: 3.32
 */
IdeSnippet *
ide_snippet_copy (IdeSnippet *self)
{
  IdeSnippetChunk *chunk;
  IdeSnippet *ret;

  g_return_val_if_fail (IDE_IS_SNIPPET (self), NULL);

  ret = g_object_new (IDE_TYPE_SNIPPET,
                      "trigger", self->trigger,
                      "language", self->language,
                      "description", self->description,
                      NULL);

  for (guint i = 0; i < self->chunks->len; i++)
    {
      chunk = g_ptr_array_index (self->chunks, i);
      chunk = ide_snippet_chunk_copy (chunk);
      ide_snippet_add_chunk (ret, chunk);
      g_object_unref (chunk);
    }

  return ret;
}

/**
 * ide_snippet_get_tab_stop:
 * @self: a #IdeSnippet
 *
 * Gets the current tab stop for the snippet. This is changed
 * as the user Tab's through the edit points.
 *
 * Returns: The tab stop, or -1 if unset.
 *
 * Since: 3.32
 */
gint
ide_snippet_get_tab_stop (IdeSnippet *self)
{
  g_return_val_if_fail (IDE_IS_SNIPPET (self), -1);

  return self->tab_stop;
}

/**
 * ide_snippet_get_n_chunks:
 * @self: a #IdeSnippet
 *
 * Gets the number of chunks in the snippet. Not all chunks
 * are editable.
 *
 * Returns: The number of chunks.
 *
 * Since: 3.32
 */
guint
ide_snippet_get_n_chunks (IdeSnippet *self)
{
  g_return_val_if_fail (IDE_IS_SNIPPET (self), 0);

  return self->chunks->len;
}

/**
 * ide_snippet_get_nth_chunk:
 * @self: an #IdeSnippet
 * @n: the nth chunk to get
 *
 * Gets the chunk at @n.
 *
 * Returns: (transfer none): an #IdeSnippetChunk
 *
 * Since: 3.32
 */
IdeSnippetChunk *
ide_snippet_get_nth_chunk (IdeSnippet *self,
                           guint       n)
{
  g_return_val_if_fail (IDE_IS_SNIPPET (self), 0);

  if (n < self->chunks->len)
    return g_ptr_array_index (self->chunks, n);

  return NULL;
}

/**
 * ide_snippet_get_trigger:
 * @self: a #IdeSnippet
 *
 * Gets the trigger for the source snippet
 *
 * Returns: (nullable): A trigger if specified
 *
 * Since: 3.32
 */
const gchar *
ide_snippet_get_trigger (IdeSnippet *self)
{
  g_return_val_if_fail (IDE_IS_SNIPPET (self), NULL);

  return self->trigger;
}

/**
 * ide_snippet_set_trigger:
 * @self: a #IdeSnippet
 * @trigger: the trigger word
 *
 * Sets the trigger for the snippet.
 *
 * Since: 3.32
 */
void
ide_snippet_set_trigger (IdeSnippet  *self,
                         const gchar *trigger)
{
  g_return_if_fail (IDE_IS_SNIPPET (self));

  if (self->trigger != trigger)
    {
      g_free (self->trigger);
      self->trigger = g_strdup (trigger);
    }
}

/**
 * ide_snippet_get_language:
 * @self: a #IdeSnippet
 *
 * Gets the language used for the source snippet.
 *
 * The language identifier matches the #GtkSourceLanguage:id
 * property.
 *
 * Returns: the language identifier
 *
 * Since: 3.32
 */
const gchar *
ide_snippet_get_language (IdeSnippet *self)
{
  g_return_val_if_fail (IDE_IS_SNIPPET (self), NULL);

  return self->language;
}

/**
 * ide_snippet_set_language:
 * @self: a #IdeSnippet
 *
 * Sets the language identifier for the snippet.
 *
 * This should match the #GtkSourceLanguage:id identifier.
 *
 * Since: 3.32
 */
void
ide_snippet_set_language (IdeSnippet  *self,
                          const gchar *language)
{
  g_return_if_fail (IDE_IS_SNIPPET (self));

  language = g_intern_string (language);

  if (self->language != language)
    {
      self->language = language;
      g_object_notify_by_pspec (G_OBJECT (self), properties [PROP_LANGUAGE]);
    }
}

/**
 * ide_snippet_get_description:
 * @self: a #IdeSnippet
 *
 * Gets the description for the snippet.
 *
 * Since: 3.32
 */
const gchar *
ide_snippet_get_description (IdeSnippet *self)
{
  g_return_val_if_fail (IDE_IS_SNIPPET (self), NULL);

  return self->description;
}

/**
 * ide_snippet_set_description:
 * @self: a #IdeSnippet
 * @description: the snippet description
 *
 * Sets the description for the snippet.
 *
 * Since: 3.32
 */
void
ide_snippet_set_description (IdeSnippet  *self,
                             const gchar *description)
{
  g_return_if_fail (IDE_IS_SNIPPET (self));

  if (self->description != description)
    {
      g_free (self->description);
      self->description = g_strdup (description);
    }
}

static gint
ide_snippet_get_offset (IdeSnippet  *self,
                        GtkTextIter *iter)
{
  GtkTextIter begin;
  gint ret;

  g_return_val_if_fail (IDE_IS_SNIPPET (self), 0);
  g_return_val_if_fail (iter, 0);

  gtk_text_buffer_get_iter_at_mark (self->buffer, &begin, self->mark_begin);
  ret = gtk_text_iter_get_offset (iter) - gtk_text_iter_get_offset (&begin);
  ret = MAX (0, ret);

  return ret;
}

static gint
ide_snippet_get_index (IdeSnippet  *self,
                       GtkTextIter *iter)
{
  gint offset;
  gint run;

  g_return_val_if_fail (IDE_IS_SNIPPET (self), 0);
  g_return_val_if_fail (iter, 0);

  offset = ide_snippet_get_offset (self, iter);

  for (guint i = 0; i < self->runs->len; i++)
    {
      run = g_array_index (self->runs, gint, i);
      offset -= run;
      if (offset <= 0)
        {
          /*
           * HACK: This is the central part of the hack by using offsets
           *       instead of textmarks (which gives us lots of gravity grief).
           *       We guess which snippet it is based on the current chunk.
           */
          if (self->current_chunk > -1 && (i + 1) == (guint)self->current_chunk)
            return (i + 1);
          return i;
        }
    }

  return (self->runs->len - 1);
}

static gboolean
ide_snippet_within_bounds (IdeSnippet  *self,
                           GtkTextIter *iter)
{
  GtkTextIter begin;
  GtkTextIter end;
  gboolean ret;

  g_return_val_if_fail (IDE_IS_SNIPPET (self), FALSE);
  g_return_val_if_fail (iter, FALSE);

  gtk_text_buffer_get_iter_at_mark (self->buffer, &begin, self->mark_begin);
  gtk_text_buffer_get_iter_at_mark (self->buffer, &end, self->mark_end);

  ret = ((gtk_text_iter_compare (&begin, iter) <= 0) &&
         (gtk_text_iter_compare (&end, iter) >= 0));

  return ret;
}

gboolean
ide_snippet_insert_set (IdeSnippet  *self,
                        GtkTextMark *mark)
{
  GtkTextIter iter;

  g_return_val_if_fail (IDE_IS_SNIPPET (self), FALSE);
  g_return_val_if_fail (GTK_IS_TEXT_MARK (mark), FALSE);

  gtk_text_buffer_get_iter_at_mark (self->buffer, &iter, mark);

  if (!ide_snippet_within_bounds (self, &iter))
    return FALSE;

  self->current_chunk = ide_snippet_get_index (self, &iter);

  return TRUE;
}

static void
ide_snippet_get_nth_chunk_range (IdeSnippet  *self,
                                 gint         n,
                                 GtkTextIter *begin,
                                 GtkTextIter *end)
{
  gint run;
  gint i;

  g_return_if_fail (IDE_IS_SNIPPET (self));
  g_return_if_fail (n >= 0);
  g_return_if_fail (begin);
  g_return_if_fail (end);

  gtk_text_buffer_get_iter_at_mark (self->buffer, begin, self->mark_begin);

  for (i = 0; i < n; i++)
    {
      run = g_array_index (self->runs, gint, i);
      gtk_text_iter_forward_chars (begin, run);
    }

  gtk_text_iter_assign (end, begin);
  run = g_array_index (self->runs, gint, n);
  gtk_text_iter_forward_chars (end, run);
}

void
ide_snippet_get_chunk_range (IdeSnippet      *self,
                             IdeSnippetChunk *chunk,
                             GtkTextIter     *begin,
                             GtkTextIter     *end)
{
  IdeSnippetChunk *item;
  guint i;

  g_return_if_fail (IDE_IS_SNIPPET (self));
  g_return_if_fail (IDE_IS_SNIPPET_CHUNK (chunk));

  for (i = 0; i < self->chunks->len; i++)
    {
      item = g_ptr_array_index (self->chunks, i);

      if (item == chunk)
        {
          ide_snippet_get_nth_chunk_range (self, i, begin, end);
          return;
        }
    }

  g_warning ("Chunk does not belong to snippet.");
}

static void
ide_snippet_select_chunk (IdeSnippet *self,
                          gint        n)
{
  GtkTextIter begin;
  GtkTextIter end;

  IDE_ENTRY;

  g_return_if_fail (IDE_IS_SNIPPET (self));
  g_return_if_fail (n >= 0);
  g_return_if_fail ((guint)n < self->runs->len);

  ide_snippet_get_nth_chunk_range (self, n, &begin, &end);

  gtk_text_iter_order (&begin, &end);

  IDE_TRACE_MSG ("Selecting chunk %d with range %d:%d to %d:%d (offset %d+%d)",
                 n,
                 gtk_text_iter_get_line (&begin) + 1,
                 gtk_text_iter_get_line_offset (&begin) + 1,
                 gtk_text_iter_get_line (&end) + 1,
                 gtk_text_iter_get_line_offset (&end) + 1,
                 gtk_text_iter_get_offset (&begin),
                 gtk_text_iter_get_offset (&end) - gtk_text_iter_get_offset (&begin));

  gtk_text_buffer_select_range (self->buffer, &begin, &end);

#ifdef IDE_ENABLE_TRACE
  {
    GtkTextIter set_begin;
    GtkTextIter set_end;

    gtk_text_buffer_get_selection_bounds (self->buffer, &set_begin, &set_end);

    g_assert (gtk_text_iter_equal (&set_begin, &begin));
    g_assert (gtk_text_iter_equal (&set_end, &end));
  }
#endif

  self->current_chunk = n;

  IDE_EXIT;
}

gboolean
ide_snippet_move_next (IdeSnippet *self)
{
  GtkTextIter iter;

  IDE_ENTRY;

  g_return_val_if_fail (IDE_IS_SNIPPET (self), FALSE);

  if (self->tab_stop > self->max_tab_stop)
    IDE_RETURN (FALSE);

  self->tab_stop++;

  for (guint i = 0; i < self->chunks->len; i++)
    {
      IdeSnippetChunk *chunk = g_ptr_array_index (self->chunks, i);

      if (ide_snippet_chunk_get_tab_stop (chunk) == self->tab_stop)
        {
          ide_snippet_select_chunk (self, i);
          IDE_RETURN (TRUE);
        }
    }

  for (guint i = 0; i < self->chunks->len; i++)
    {
      IdeSnippetChunk *chunk = g_ptr_array_index (self->chunks, i);

      if (ide_snippet_chunk_get_tab_stop (chunk) == 0)
        {
          ide_snippet_select_chunk (self, i);
          IDE_RETURN (FALSE);
        }
    }

  IDE_TRACE_MSG ("No more tab stops, moving to end of snippet");

  gtk_text_buffer_get_iter_at_mark (self->buffer, &iter, self->mark_end);
  gtk_text_buffer_select_range (self->buffer, &iter, &iter);
  self->current_chunk = self->chunks->len - 1;

  IDE_RETURN (FALSE);
}

gboolean
ide_snippet_move_previous (IdeSnippet *self)
{
  IDE_ENTRY;

  g_return_val_if_fail (IDE_IS_SNIPPET (self), FALSE);

  self->tab_stop = MAX (1, self->tab_stop - 1);

  for (guint i = 0; i < self->chunks->len; i++)
    {
      IdeSnippetChunk *chunk = g_ptr_array_index (self->chunks, i);

      if (ide_snippet_chunk_get_tab_stop (chunk) == self->tab_stop)
        {
          ide_snippet_select_chunk (self, i);
          IDE_RETURN (TRUE);
        }
    }

  IDE_TRACE_MSG ("No previous tab stop to select, ignoring");

  IDE_RETURN (FALSE);
}

static void
ide_snippet_update_context (IdeSnippet *self)
{
  IdeSnippetContext *context;

  IDE_ENTRY;

  g_return_if_fail (IDE_IS_SNIPPET (self));

  if (self->chunks == NULL || self->chunks->len == 0)
    IDE_EXIT;

  context = ide_snippet_get_context (self);

  ide_snippet_context_emit_changed (context);

  for (guint i = 0; i < self->chunks->len; i++)
    {
      IdeSnippetChunk *chunk = g_ptr_array_index (self->chunks, i);
      gint tab_stop;

      g_assert (IDE_IS_SNIPPET_CHUNK (chunk));

      tab_stop = ide_snippet_chunk_get_tab_stop (chunk);

      if (tab_stop > 0)
        {
          const gchar *text;

          if (NULL != (text = ide_snippet_chunk_get_text (chunk)))
            {
              gchar key[12];

              g_snprintf (key, sizeof key, "%d", tab_stop);
              key[sizeof key - 1] = '\0';

              ide_snippet_context_add_variable (context, key, text);
            }
        }
    }

  ide_snippet_context_emit_changed (context);

  IDE_EXIT;
}

static void
ide_snippet_clear_tags (IdeSnippet *self)
{
  g_assert (IDE_IS_SNIPPET (self));

  if (self->mark_begin != NULL && self->mark_end != NULL)
    {
      GtkTextBuffer *buffer;
      GtkTextIter begin;
      GtkTextIter end;

      buffer = gtk_text_mark_get_buffer (self->mark_begin);

      gtk_text_buffer_get_iter_at_mark (buffer, &begin, self->mark_begin);
      gtk_text_buffer_get_iter_at_mark (buffer, &end, self->mark_end);

      gtk_text_buffer_remove_tag_by_name (buffer,
                                          TAG_SNIPPET_TAB_STOP,
                                          &begin, &end);
    }
}

static void
ide_snippet_update_tags (IdeSnippet *self)
{
  GtkTextBuffer *buffer;
  guint i;

  g_assert (IDE_IS_SNIPPET (self));

  ide_snippet_clear_tags (self);

  buffer = gtk_text_mark_get_buffer (self->mark_begin);

  for (i = 0; i < self->chunks->len; i++)
    {
      IdeSnippetChunk *chunk = g_ptr_array_index (self->chunks, i);
      gint tab_stop = ide_snippet_chunk_get_tab_stop (chunk);

      if (tab_stop >= 0)
        {
          GtkTextIter begin;
          GtkTextIter end;

          ide_snippet_get_chunk_range (self, chunk, &begin, &end);
          gtk_text_buffer_apply_tag_by_name (buffer,
                                             TAG_SNIPPET_TAB_STOP,
                                             &begin, &end);
        }
    }
}

gboolean
ide_snippet_begin (IdeSnippet    *self,
                   GtkTextBuffer *buffer,
                   GtkTextIter   *iter)
{
  IdeSnippetContext *context;
  gboolean ret;

  g_return_val_if_fail (IDE_IS_SNIPPET (self), FALSE);
  g_return_val_if_fail (!self->buffer, FALSE);
  g_return_val_if_fail (!self->mark_begin, FALSE);
  g_return_val_if_fail (!self->mark_end, FALSE);
  g_return_val_if_fail (GTK_IS_TEXT_BUFFER (buffer), FALSE);
  g_return_val_if_fail (iter, FALSE);

  self->inserted = TRUE;

  context = ide_snippet_get_context (self);

  ide_snippet_update_context (self);
  ide_snippet_context_emit_changed (context);
  ide_snippet_update_context (self);

  self->buffer = g_object_ref (buffer);
  self->mark_begin = gtk_text_buffer_create_mark (buffer, NULL, iter, TRUE);
  g_object_add_weak_pointer (G_OBJECT (self->mark_begin),
                             (gpointer *) &self->mark_begin);

  gtk_text_buffer_begin_user_action (buffer);

  for (guint i = 0; i < self->chunks->len; i++)
    {
      IdeSnippetChunk *chunk;
      const gchar *text;

      chunk = g_ptr_array_index (self->chunks, i);

      if ((text = ide_snippet_chunk_get_text (chunk)))
        {
          gint len;

          len = g_utf8_strlen (text, -1);
          g_array_append_val (self->runs, len);
          gtk_text_buffer_insert (buffer, iter, text, -1);
        }
    }

  self->mark_end = gtk_text_buffer_create_mark (buffer, NULL, iter, FALSE);
  g_object_add_weak_pointer (G_OBJECT (self->mark_end),
                             (gpointer *) &self->mark_end);

  g_object_ref (self->mark_begin);
  g_object_ref (self->mark_end);

  gtk_text_buffer_end_user_action (buffer);

  ide_snippet_update_tags (self);

  ret = ide_snippet_move_next (self);

  return ret;
}

void
ide_snippet_finish (IdeSnippet *self)
{
  g_return_if_fail (IDE_IS_SNIPPET (self));

  ide_snippet_clear_tags (self);

  g_clear_object (&self->mark_begin);
  g_clear_object (&self->mark_end);
  g_clear_object (&self->buffer);
}

void
ide_snippet_pause (IdeSnippet *self)
{
  g_return_if_fail (IDE_IS_SNIPPET (self));
}

void
ide_snippet_unpause (IdeSnippet *self)
{
  g_return_if_fail (IDE_IS_SNIPPET (self));
}

void
ide_snippet_add_chunk (IdeSnippet      *self,
                       IdeSnippetChunk *chunk)
{
  gint tab_stop;

  g_return_if_fail (IDE_IS_SNIPPET (self));
  g_return_if_fail (IDE_IS_SNIPPET_CHUNK (chunk));
  g_return_if_fail (!self->inserted);

  g_ptr_array_add (self->chunks, g_object_ref (chunk));

  ide_snippet_chunk_set_context (chunk, self->snippet_context);

  tab_stop = ide_snippet_chunk_get_tab_stop (chunk);
  self->max_tab_stop = MAX (self->max_tab_stop, tab_stop);
}

static gchar *
ide_snippet_get_nth_text (IdeSnippet *self,
                          gint        n)
{
  GtkTextIter iter;
  GtkTextIter end;
  gchar *ret;
  gint i;

  g_return_val_if_fail (IDE_IS_SNIPPET (self), NULL);
  g_return_val_if_fail (n >= 0, NULL);

  gtk_text_buffer_get_iter_at_mark (self->buffer, &iter, self->mark_begin);

  for (i = 0; i < n; i++)
    gtk_text_iter_forward_chars (&iter, g_array_index (self->runs, gint, i));

  gtk_text_iter_assign (&end, &iter);
  gtk_text_iter_forward_chars (&end, g_array_index (self->runs, gint, n));

  ret = gtk_text_buffer_get_text (self->buffer, &iter, &end, TRUE);

  return ret;
}

static void
ide_snippet_replace_chunk_text (IdeSnippet  *self,
                                gint         n,
                                const gchar *text)
{
  GtkTextIter begin;
  GtkTextIter end;
  gint diff = 0;

  g_return_if_fail (IDE_IS_SNIPPET (self));
  g_return_if_fail (n >= 0);
  g_return_if_fail (text);

  /*
   * This replaces the text for the snippet. We insert new text before
   * we delete the old text to ensure things are more stable as we
   * manipulate the runs. Avoiding zero-length runs, even temporarily
   * can be helpful.
   */

  ide_snippet_get_nth_chunk_range (self, n, &begin, &end);

  if (!gtk_text_iter_equal (&begin, &end))
    {
      gtk_text_iter_order (&begin, &end);
      diff = gtk_text_iter_get_offset (&end) - gtk_text_iter_get_offset (&begin);
    }

  g_array_index (self->runs, gint, n) += g_utf8_strlen (text, -1);
  gtk_text_buffer_insert (self->buffer, &begin, text, -1);

  /* At this point, begin should be updated to the end of where we inserted
   * our new text. If `diff` is non-zero, then we need to remove those
   * characters immediately after `begin`.
   */
  if (diff != 0)
    {
      end = begin;
      gtk_text_iter_forward_chars (&end, diff);
      g_array_index (self->runs, gint, n) -= diff;
      gtk_text_buffer_delete (self->buffer, &begin, &end);
    }
}

static void
ide_snippet_rewrite_updated_chunks (IdeSnippet *self)
{
  g_return_if_fail (IDE_IS_SNIPPET (self));

  for (guint i = 0; i < self->chunks->len; i++)
    {
      IdeSnippetChunk *chunk = g_ptr_array_index (self->chunks, i);
      g_autofree gchar *real_text = NULL;
      const gchar *text;

      text = ide_snippet_chunk_get_text (chunk);
      real_text = ide_snippet_get_nth_text (self, i);

      if (!dzl_str_equal0 (text, real_text))
        ide_snippet_replace_chunk_text (self, i, text);
    }
}

void
ide_snippet_before_insert_text (IdeSnippet    *self,
                                GtkTextBuffer *buffer,
                                GtkTextIter   *iter,
                                gchar         *text,
                                gint           len)
{
  gint utf8_len;
  gint n;

  IDE_ENTRY;

  g_return_if_fail (IDE_IS_SNIPPET (self));
  g_return_if_fail (self->current_chunk >= 0);
  g_return_if_fail (GTK_IS_TEXT_BUFFER (buffer));
  g_return_if_fail (iter);

  n = ide_snippet_get_index (self, iter);
  utf8_len = g_utf8_strlen (text, len);
  g_array_index (self->runs, gint, n) += utf8_len;

#if 0
  g_print ("I: ");
  for (n = 0; n < self->runs->len; n++)
    g_print ("%d ", g_array_index (self->runs, gint, n));
  g_print ("\n");
#endif

  IDE_EXIT;
}

void
ide_snippet_after_insert_text (IdeSnippet    *self,
                               GtkTextBuffer *buffer,
                               GtkTextIter   *iter,
                               gchar         *text,
                               gint           len)
{
  IdeSnippetChunk *chunk;
  GtkTextMark *here;
  gchar *new_text;
  gint n;

  IDE_ENTRY;

  g_return_if_fail (IDE_IS_SNIPPET (self));
  g_return_if_fail (self->current_chunk >= 0);
  g_return_if_fail (GTK_IS_TEXT_BUFFER (buffer));
  g_return_if_fail (iter);

  n = ide_snippet_get_index (self, iter);
  chunk = g_ptr_array_index (self->chunks, n);
  new_text = ide_snippet_get_nth_text (self, n);
  ide_snippet_chunk_set_text (chunk, new_text);
  ide_snippet_chunk_set_text_set (chunk, TRUE);
  g_free (new_text);

  here = gtk_text_buffer_create_mark (buffer, NULL, iter, TRUE);

  ide_snippet_update_context (self);
  ide_snippet_update_context (self);
  ide_snippet_rewrite_updated_chunks (self);

  gtk_text_buffer_get_iter_at_mark (buffer, iter, here);
  gtk_text_buffer_delete_mark (buffer, here);

  ide_snippet_update_tags (self);

#if 0
  ide_snippet_context_dump (self->snippet_context);
#endif

  IDE_EXIT;
}

void
ide_snippet_before_delete_range (IdeSnippet    *self,
                                 GtkTextBuffer *buffer,
                                 GtkTextIter   *begin,
                                 GtkTextIter   *end)
{
  gint *run;
  gint len;
  gint n;
  gint i;
  gint lower_bound = -1;
  gint upper_bound = -1;

  IDE_ENTRY;

  g_return_if_fail (IDE_IS_SNIPPET (self));
  g_return_if_fail (GTK_IS_TEXT_BUFFER (buffer));
  g_return_if_fail (begin);
  g_return_if_fail (end);

  len = gtk_text_iter_get_offset (end) - gtk_text_iter_get_offset (begin);

  n = ide_snippet_get_index (self, begin);
  if (n < 0)
    IDE_EXIT;

  self->current_chunk = n;

  while (len != 0 && (guint)n < self->runs->len)
    {
      if (lower_bound == -1 || n < lower_bound)
        lower_bound = n;
      if (n > upper_bound)
        upper_bound = n;
      run = &g_array_index (self->runs, gint, n);
      if (len > *run)
        {
          len -= *run;
          *run = 0;
          n++;
          continue;
        }
      *run -= len;
      break;
    }

  if (lower_bound == -1 || upper_bound == -1)
    return;

  for (i = lower_bound; i <= upper_bound; i++)
    {
      IdeSnippetChunk *chunk = g_ptr_array_index (self->chunks, i);
      g_autofree gchar *new_text = NULL;

      new_text = ide_snippet_get_nth_text (self, i);
      ide_snippet_chunk_set_text (chunk, new_text);
      ide_snippet_chunk_set_text_set (chunk, TRUE);
    }

#if 0
  g_print ("D: ");
  for (n = 0; n < self->runs->len; n++)
    g_print ("%d ", g_array_index (self->runs, gint, n));
  g_print ("\n");
#endif

  IDE_EXIT;
}

void
ide_snippet_after_delete_range (IdeSnippet    *self,
                                GtkTextBuffer *buffer,
                                GtkTextIter   *begin,
                                GtkTextIter   *end)
{
  GtkTextMark *here;

  IDE_ENTRY;

  g_return_if_fail (IDE_IS_SNIPPET (self));
  g_return_if_fail (GTK_IS_TEXT_BUFFER (buffer));
  g_return_if_fail (begin);
  g_return_if_fail (end);

  here = gtk_text_buffer_create_mark (buffer, NULL, begin, TRUE);

  ide_snippet_update_context (self);
  ide_snippet_update_context (self);
  ide_snippet_rewrite_updated_chunks (self);

  gtk_text_buffer_get_iter_at_mark (buffer, begin, here);
  gtk_text_buffer_get_iter_at_mark (buffer, end, here);
  gtk_text_buffer_delete_mark (buffer, here);

  ide_snippet_update_tags (self);

#if 0
  ide_snippet_context_dump (self->snippet_context);
#endif

  IDE_EXIT;
}

/**
 * ide_snippet_get_mark_begin:
 * @self: an #IdeSnippet
 *
 * Gets the begin text mark, which is only set when the snippet is
 * actively being edited.
 *
 * Returns: (transfer none) (nullable): a #GtkTextMark or %NULL
 *
 * Since: 3.32
 */
GtkTextMark *
ide_snippet_get_mark_begin (IdeSnippet *self)
{
  g_return_val_if_fail (IDE_IS_SNIPPET (self), NULL);

  return self->mark_begin;
}

/**
 * ide_snippet_get_mark_end:
 * @self: an #IdeSnippet
 *
 * Gets the end text mark, which is only set when the snippet is
 * actively being edited.
 *
 * Returns: (transfer none) (nullable): a #GtkTextMark or %NULL
 *
 * Since: 3.32
 */
GtkTextMark *
ide_snippet_get_mark_end (IdeSnippet *self)
{
  g_return_val_if_fail (IDE_IS_SNIPPET (self), NULL);

  return self->mark_end;
}

/**
 * ide_snippet_get_context:
 * @self: an #IdeSnippet
 *
 * Get's the context used for expanding the snippet.
 *
 * Returns: (nullable) (transfer none): an #IdeSnippetContext
 *
 * Since: 3.32
 */
IdeSnippetContext *
ide_snippet_get_context (IdeSnippet *self)
{
  g_return_val_if_fail (IDE_IS_SNIPPET (self), NULL);

  if (!self->snippet_context)
    {
      IdeSnippetChunk *chunk;
      guint i;

      self->snippet_context = ide_snippet_context_new ();

      for (i = 0; i < self->chunks->len; i++)
        {
          chunk = g_ptr_array_index (self->chunks, i);
          ide_snippet_chunk_set_context (chunk, self->snippet_context);
        }
    }

  return self->snippet_context;
}

static void
ide_snippet_dispose (GObject *object)
{
  IdeSnippet *self = (IdeSnippet *)object;

  if (self->mark_begin)
    {
      g_object_remove_weak_pointer (G_OBJECT (self->mark_begin),
                                    (gpointer *) &self->mark_begin);
      gtk_text_buffer_delete_mark (self->buffer, self->mark_begin);
      self->mark_begin = NULL;
    }

  if (self->mark_end)
    {
      g_object_remove_weak_pointer (G_OBJECT (self->mark_end),
                                    (gpointer *) &self->mark_end);
      gtk_text_buffer_delete_mark (self->buffer, self->mark_end);
      self->mark_end = NULL;
    }

  g_clear_pointer (&self->runs, g_array_unref);
  g_clear_pointer (&self->chunks, g_ptr_array_unref);

  g_clear_object (&self->buffer);
  g_clear_object (&self->snippet_context);

  G_OBJECT_CLASS (ide_snippet_parent_class)->dispose (object);
}

static void
ide_snippet_finalize (GObject *object)
{
  IdeSnippet *self = (IdeSnippet *)object;

  g_clear_pointer (&self->description, g_free);
  g_clear_pointer (&self->trigger, g_free);
  g_clear_object (&self->buffer);

  G_OBJECT_CLASS (ide_snippet_parent_class)->finalize (object);

  DZL_COUNTER_DEC (instances);
}

static void
ide_snippet_get_property (GObject    *object,
                          guint       prop_id,
                          GValue     *value,
                          GParamSpec *pspec)
{
  IdeSnippet *self = IDE_SNIPPET (object);

  switch (prop_id)
    {
    case PROP_BUFFER:
      g_value_set_object (value, self->buffer);
      break;

    case PROP_MARK_BEGIN:
      g_value_set_object (value, self->mark_begin);
      break;

    case PROP_MARK_END:
      g_value_set_object (value, self->mark_end);
      break;

    case PROP_TRIGGER:
      g_value_set_string (value, self->trigger);
      break;

    case PROP_LANGUAGE:
      g_value_set_string (value, self->language);
      break;

    case PROP_DESCRIPTION:
      g_value_set_string (value, self->description);
      break;

    case PROP_TAB_STOP:
      g_value_set_uint (value, self->tab_stop);
      break;

    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
    }
}

static void
ide_snippet_set_property (GObject      *object,
                          guint         prop_id,
                          const GValue *value,
                          GParamSpec   *pspec)
{
  IdeSnippet *self = IDE_SNIPPET (object);

  switch (prop_id)
    {
    case PROP_TRIGGER:
      ide_snippet_set_trigger (self, g_value_get_string (value));
      break;

    case PROP_LANGUAGE:
      ide_snippet_set_language (self, g_value_get_string (value));
      break;

    case PROP_DESCRIPTION:
      ide_snippet_set_description (self, g_value_get_string (value));
      break;

    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
    }
}

static void
ide_snippet_class_init (IdeSnippetClass *klass)
{
  GObjectClass *object_class = G_OBJECT_CLASS (klass);

  object_class->dispose = ide_snippet_dispose;
  object_class->finalize = ide_snippet_finalize;
  object_class->get_property = ide_snippet_get_property;
  object_class->set_property = ide_snippet_set_property;

  properties[PROP_BUFFER] =
    g_param_spec_object ("buffer",
                         "Buffer",
                         "The GtkTextBuffer for the snippet.",
                         GTK_TYPE_TEXT_BUFFER,
                         (G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));

  properties[PROP_MARK_BEGIN] =
    g_param_spec_object ("mark-begin",
                         "Mark Begin",
                         "The beginning text mark.",
                         GTK_TYPE_TEXT_MARK,
                         (G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));

  properties[PROP_MARK_END] =
    g_param_spec_object ("mark-end",
                         "Mark End",
                         "The ending text mark.",
                         GTK_TYPE_TEXT_MARK,
                         (G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));

  properties[PROP_TRIGGER] =
    g_param_spec_string ("trigger",
                         "Trigger",
                         "The trigger for the snippet.",
                         NULL,
                         (G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

  properties[PROP_LANGUAGE] =
    g_param_spec_string ("language",
                         "Language",
                         "The language for the snippet.",
                         NULL,
                         (G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

  properties[PROP_DESCRIPTION] =
    g_param_spec_string ("description",
                         "Description",
                         "The description for the snippet.",
                         NULL,
                         (G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));

  properties[PROP_TAB_STOP] =
    g_param_spec_int ("tab-stop",
                      "Tab Stop",
                      "The current tab stop.",
                      -1,
                      G_MAXINT,
                      -1,
                      (G_PARAM_READABLE | G_PARAM_STATIC_STRINGS));

  g_object_class_install_properties (object_class, LAST_PROP, properties);
}

static void
ide_snippet_init (IdeSnippet *self)
{
  DZL_COUNTER_INC (instances);

  self->max_tab_stop = -1;
  self->chunks = g_ptr_array_new_with_free_func (g_object_unref);
  self->runs = g_array_new (FALSE, FALSE, sizeof (gint));
}

/**
 * ide_snippet_get_full_text:
 * @self: a #IdeSnippet
 *
 * Gets the contents of the snippet as currently edited by the user.
 *
 * Returns: (transfer full): a newly allocated string containing the full
 *   contents of all the snippet chunks.
 *
 * Since: 3.32
 */
gchar *
ide_snippet_get_full_text (IdeSnippet *self)
{
  GtkTextIter begin;
  GtkTextIter end;

  g_return_val_if_fail (IDE_IS_SNIPPET (self), NULL);

  if (self->mark_begin == NULL || self->mark_end == NULL)
    return NULL;

  gtk_text_buffer_get_iter_at_mark (self->buffer, &begin, self->mark_begin);
  gtk_text_buffer_get_iter_at_mark (self->buffer, &end, self->mark_end);

  return gtk_text_iter_get_slice (&begin, &end);
}

/**
 * ide_snippet_replace_current_chunk_text:
 * @self: a #IdeSnippet
 * @new_text: the text to use as the replacement
 *
 * This replaces the current chunk (if any) to contain the contents of
 * @new_text.
 *
 * This function is primarily useful to the #IdeSourceView as it updates
 * content as the user types.
 *
 * Since: 3.32
 */
void
ide_snippet_replace_current_chunk_text (IdeSnippet  *self,
                                        const gchar *new_text)
{
  IdeSnippetChunk *chunk;
  gint utf8_len;

  g_return_if_fail (IDE_IS_SNIPPET (self));
  g_return_if_fail (self->chunks != NULL);

  if (self->current_chunk < 0 || self->current_chunk >= self->chunks->len)
    return;

  chunk = g_ptr_array_index (self->chunks, self->current_chunk);

  ide_snippet_chunk_set_text (chunk, new_text);
  ide_snippet_chunk_set_text_set (chunk, TRUE);

  g_assert (self->current_chunk >= 0);
  g_assert (self->current_chunk < self->runs->len);

  utf8_len = g_utf8_strlen (new_text, -1);
  g_array_index (self->runs, gint, self->current_chunk) = utf8_len;
}

/**
 * ide_snippet_dump:
 * @self: a #IdeSnippet
 *
 * This is a debugging function to print information about a chunk to stderr.
 * Plugin developers might use this to track down issues when using a snippet.
 *
 * Since: 3.32
 */
void
ide_snippet_dump (IdeSnippet *self)
{
  guint offset = 0;

  g_return_if_fail (IDE_IS_SNIPPET (self));

  /* For debugging purposes */

  g_printerr ("Snippet(trigger=%s, language=%s, tab_stop=%d, current_chunk=%d)\n",
              self->trigger, self->language ?: "none", self->tab_stop, self->current_chunk);

  g_assert (self->chunks->len == self->runs->len);

  for (guint i = 0; i < self->chunks->len; i++)
    {
      IdeSnippetChunk *chunk = g_ptr_array_index (self->chunks, i);
      g_autofree gchar *spec_escaped = NULL;
      g_autofree gchar *text_escaped = NULL;
      const gchar *spec;
      const gchar *text;
      gint run_length = g_array_index (self->runs, gint, i);

      g_assert (IDE_IS_SNIPPET_CHUNK (chunk));

      text = ide_snippet_chunk_get_text (chunk);
      text_escaped = g_strescape (text, NULL);

      spec = ide_snippet_chunk_get_spec (chunk);
      spec_escaped = g_strescape (spec, NULL);

      g_printerr ("  Chunk(nth=%d, tab_stop=%d, position=%d (%d), spec=%s, text=%s)\n",
                  i,
                  ide_snippet_chunk_get_tab_stop (chunk),
                  offset, run_length,
                  spec_escaped,
                  text_escaped);

      offset += run_length;
    }
}