/**
 * @file
 * Sidebar functions
 *
 * @authors
 * Copyright (C) 2020 Pietro Cerutti <gahr@gahr.ch>
 * Copyright (C) 2020-2023 Richard Russon <rich@flatcap.org>
 *
 * @copyright
 * 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 2 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/>.
 */

/**
 * @page sidebar_functions Sidebar functions
 *
 * Sidebar functions
 */

#include "config.h"
#include <stdbool.h>
#include <stddef.h>
#include "private.h"
#include "mutt/lib.h"
#include "config/lib.h"
#include "core/lib.h"
#include "gui/lib.h"
#include "functions.h"
#include "lib.h"
#include "index/lib.h"

/**
 * sb_next - Find the next unhidden Mailbox
 * @param wdata Sidebar data
 * @retval true Mailbox found
 */
bool sb_next(struct SidebarWindowData *wdata)
{
  struct SbEntry **sbep = NULL;
  ARRAY_FOREACH_FROM(sbep, &wdata->entries, wdata->hil_index + 1)
  {
    if (!(*sbep)->is_hidden)
    {
      wdata->hil_index = ARRAY_FOREACH_IDX_sbep;
      return true;
    }
  }

  return false;
}

/**
 * sb_next_new - Return the next mailbox with new messages
 * @param wdata Sidebar data
 * @param begin Starting index for searching
 * @param end   Ending index for searching
 * @retval ptr  Pointer to the first entry with new messages
 * @retval NULL None could be found
 */
static struct SbEntry **sb_next_new(struct SidebarWindowData *wdata, size_t begin, size_t end)
{
  struct SbEntry **sbep = NULL;
  ARRAY_FOREACH_FROM_TO(sbep, &wdata->entries, begin, end)
  {
    if ((*sbep)->mailbox->has_new || ((*sbep)->mailbox->msg_unread != 0))
      return sbep;
  }
  return NULL;
}

/**
 * sb_prev - Find the previous unhidden Mailbox
 * @param wdata Sidebar data
 * @retval true Mailbox found
 */
bool sb_prev(struct SidebarWindowData *wdata)
{
  struct SbEntry **sbep = NULL, **prev = NULL;
  ARRAY_FOREACH_TO(sbep, &wdata->entries, wdata->hil_index)
  {
    if (!(*sbep)->is_hidden)
      prev = sbep;
  }

  if (prev)
  {
    wdata->hil_index = ARRAY_IDX(&wdata->entries, prev);
    return true;
  }

  return false;
}

/**
 * sb_prev_new - Return the previous mailbox with new messages
 * @param wdata Sidebar data
 * @param begin Starting index for searching
 * @param end   Ending index for searching
 * @retval ptr  Pointer to the first entry with new messages
 * @retval NULL None could be found
 */
static struct SbEntry **sb_prev_new(struct SidebarWindowData *wdata, size_t begin, size_t end)
{
  struct SbEntry **sbep = NULL, **prev = NULL;
  ARRAY_FOREACH_FROM_TO(sbep, &wdata->entries, begin, end)
  {
    if ((*sbep)->mailbox->has_new || ((*sbep)->mailbox->msg_unread != 0))
      prev = sbep;
  }

  return prev;
}

// -----------------------------------------------------------------------------

/**
 * op_sidebar_first - Selects the first unhidden mailbox - Implements ::sidebar_function_t - @ingroup sidebar_function_api
 */
static int op_sidebar_first(struct SidebarWindowData *wdata, int op)
{
  if (!mutt_window_is_visible(wdata->win))
    return FR_NO_ACTION;

  if (ARRAY_EMPTY(&wdata->entries) || (wdata->hil_index < 0))
    return FR_NO_ACTION;

  int orig_hil_index = wdata->hil_index;

  wdata->hil_index = 0;
  if ((*ARRAY_GET(&wdata->entries, wdata->hil_index))->is_hidden)
    if (!sb_next(wdata))
      wdata->hil_index = orig_hil_index;

  if (orig_hil_index == wdata->hil_index)
    return FR_NO_ACTION;

  wdata->win->actions |= WA_RECALC;
  return FR_SUCCESS;
}

/**
 * op_sidebar_last - Selects the last unhidden mailbox - Implements ::sidebar_function_t - @ingroup sidebar_function_api
 */
static int op_sidebar_last(struct SidebarWindowData *wdata, int op)
{
  if (!mutt_window_is_visible(wdata->win))
    return FR_NO_ACTION;

  if (ARRAY_EMPTY(&wdata->entries) || (wdata->hil_index < 0))
    return FR_NO_ACTION;

  int orig_hil_index = wdata->hil_index;

  wdata->hil_index = ARRAY_SIZE(&wdata->entries);
  if (!sb_prev(wdata))
    wdata->hil_index = orig_hil_index;

  if (orig_hil_index == wdata->hil_index)
    return FR_NO_ACTION;

  wdata->win->actions |= WA_RECALC;
  return FR_SUCCESS;
}

/**
 * op_sidebar_next - Selects the next unhidden mailbox - Implements ::sidebar_function_t - @ingroup sidebar_function_api
 */
static int op_sidebar_next(struct SidebarWindowData *wdata, int op)
{
  if (!mutt_window_is_visible(wdata->win))
    return FR_NO_ACTION;

  if (ARRAY_EMPTY(&wdata->entries) || (wdata->hil_index < 0))
    return FR_NO_ACTION;

  if (!sb_next(wdata))
    return FR_NO_ACTION;

  wdata->win->actions |= WA_RECALC;
  return FR_SUCCESS;
}

/**
 * op_sidebar_next_new - Selects the next new mailbox - Implements ::sidebar_function_t - @ingroup sidebar_function_api
 *
 * Search down the list of mail folders for one containing new mail.
 */
static int op_sidebar_next_new(struct SidebarWindowData *wdata, int op)
{
  if (!mutt_window_is_visible(wdata->win))
    return FR_NO_ACTION;

  const size_t max_entries = ARRAY_SIZE(&wdata->entries);
  if ((max_entries == 0) || (wdata->hil_index < 0))
    return FR_NO_ACTION;

  const bool c_sidebar_next_new_wrap = cs_subset_bool(NeoMutt->sub, "sidebar_next_new_wrap");
  struct SbEntry **sbep = NULL;
  if ((sbep = sb_next_new(wdata, wdata->hil_index + 1, max_entries)) ||
      (c_sidebar_next_new_wrap && (sbep = sb_next_new(wdata, 0, wdata->hil_index))))
  {
    wdata->hil_index = ARRAY_IDX(&wdata->entries, sbep);
    wdata->win->actions |= WA_RECALC;
    return FR_SUCCESS;
  }

  return FR_NO_ACTION;
}

/**
 * op_sidebar_open - Open highlighted mailbox - Implements ::sidebar_function_t - @ingroup sidebar_function_api
 */
static int op_sidebar_open(struct SidebarWindowData *wdata, int op)
{
  struct MuttWindow *win_sidebar = wdata->win;
  if (!mutt_window_is_visible(win_sidebar))
    return FR_NO_ACTION;

  struct MuttWindow *dlg = dialog_find(win_sidebar);
  index_change_folder(dlg, sb_get_highlight(win_sidebar));
  return FR_SUCCESS;
}

/**
 * op_sidebar_page_down - Selects the first entry in the next page of mailboxes - Implements ::sidebar_function_t - @ingroup sidebar_function_api
 */
static int op_sidebar_page_down(struct SidebarWindowData *wdata, int op)
{
  if (!mutt_window_is_visible(wdata->win))
    return FR_NO_ACTION;

  if (ARRAY_EMPTY(&wdata->entries) || (wdata->bot_index < 0))
    return FR_NO_ACTION;

  int orig_hil_index = wdata->hil_index;

  wdata->hil_index = wdata->bot_index;
  sb_next(wdata);
  /* If the rest of the entries are hidden, go up to the last unhidden one */
  if ((*ARRAY_GET(&wdata->entries, wdata->hil_index))->is_hidden)
    sb_prev(wdata);

  if (orig_hil_index == wdata->hil_index)
    return FR_NO_ACTION;

  wdata->win->actions |= WA_RECALC;
  return FR_SUCCESS;
}

/**
 * op_sidebar_page_up - Selects the last entry in the previous page of mailboxes - Implements ::sidebar_function_t - @ingroup sidebar_function_api
 */
static int op_sidebar_page_up(struct SidebarWindowData *wdata, int op)
{
  if (!mutt_window_is_visible(wdata->win))
    return FR_NO_ACTION;

  if (ARRAY_EMPTY(&wdata->entries) || (wdata->top_index < 0))
    return FR_NO_ACTION;

  int orig_hil_index = wdata->hil_index;

  wdata->hil_index = wdata->top_index;
  sb_prev(wdata);
  /* If the rest of the entries are hidden, go down to the last unhidden one */
  if ((*ARRAY_GET(&wdata->entries, wdata->hil_index))->is_hidden)
    sb_next(wdata);

  if (orig_hil_index == wdata->hil_index)
    return FR_NO_ACTION;

  wdata->win->actions |= WA_RECALC;
  return FR_SUCCESS;
}

/**
 * op_sidebar_prev - Selects the previous unhidden mailbox - Implements ::sidebar_function_t - @ingroup sidebar_function_api
 */
static int op_sidebar_prev(struct SidebarWindowData *wdata, int op)
{
  if (!mutt_window_is_visible(wdata->win))
    return FR_NO_ACTION;

  if (ARRAY_EMPTY(&wdata->entries) || (wdata->hil_index < 0))
    return FR_NO_ACTION;

  if (!sb_prev(wdata))
    return FR_NO_ACTION;

  wdata->win->actions |= WA_RECALC;
  return FR_SUCCESS;
}

/**
 * op_sidebar_prev_new - Selects the previous new mailbox - Implements ::sidebar_function_t - @ingroup sidebar_function_api
 *
 * Search up the list of mail folders for one containing new mail.
 */
static int op_sidebar_prev_new(struct SidebarWindowData *wdata, int op)
{
  if (!mutt_window_is_visible(wdata->win))
    return FR_NO_ACTION;

  const size_t max_entries = ARRAY_SIZE(&wdata->entries);
  if ((max_entries == 0) || (wdata->hil_index < 0))
    return FR_NO_ACTION;

  const bool c_sidebar_next_new_wrap = cs_subset_bool(NeoMutt->sub, "sidebar_next_new_wrap");
  struct SbEntry **sbep = NULL;
  if ((sbep = sb_prev_new(wdata, 0, wdata->hil_index)) ||
      (c_sidebar_next_new_wrap &&
       (sbep = sb_prev_new(wdata, wdata->hil_index + 1, max_entries))))
  {
    wdata->hil_index = ARRAY_IDX(&wdata->entries, sbep);
    wdata->win->actions |= WA_RECALC;
    return FR_SUCCESS;
  }

  return FR_NO_ACTION;
}

/**
 * op_sidebar_toggle_visible - Make the sidebar (in)visible - Implements ::sidebar_function_t - @ingroup sidebar_function_api
 */
static int op_sidebar_toggle_visible(struct SidebarWindowData *wdata, int op)
{
  bool_str_toggle(NeoMutt->sub, "sidebar_visible", NULL);
  mutt_window_reflow(NULL);
  return FR_SUCCESS;
}

/**
 * op_sidebar_toggle_virtual - Deprecated - Implements ::sidebar_function_t - @ingroup sidebar_function_api
 */
static int op_sidebar_toggle_virtual(struct SidebarWindowData *wdata, int op)
{
  return FR_SUCCESS;
}

// -----------------------------------------------------------------------------

/**
 * SidebarFunctions - All the NeoMutt functions that the Sidebar supports
 */
static const struct SidebarFunction SidebarFunctions[] = {
  // clang-format off
  { OP_SIDEBAR_FIRST,          op_sidebar_first },
  { OP_SIDEBAR_LAST,           op_sidebar_last },
  { OP_SIDEBAR_NEXT,           op_sidebar_next },
  { OP_SIDEBAR_NEXT_NEW,       op_sidebar_next_new },
  { OP_SIDEBAR_OPEN,           op_sidebar_open },
  { OP_SIDEBAR_PAGE_DOWN,      op_sidebar_page_down },
  { OP_SIDEBAR_PAGE_UP,        op_sidebar_page_up },
  { OP_SIDEBAR_PREV,           op_sidebar_prev },
  { OP_SIDEBAR_PREV_NEW,       op_sidebar_prev_new },
  { OP_SIDEBAR_TOGGLE_VIRTUAL, op_sidebar_toggle_virtual },
  { OP_SIDEBAR_TOGGLE_VISIBLE, op_sidebar_toggle_visible },
  { 0, NULL },
  // clang-format on
};

/**
 * sb_function_dispatcher - Perform a Sidebar function - Implements ::function_dispatcher_t - @ingroup dispatcher_api
 */
int sb_function_dispatcher(struct MuttWindow *win, int op)
{
  if (!win || !win->wdata)
    return FR_UNKNOWN;

  struct SidebarWindowData *wdata = win->wdata;
  int rc = FR_UNKNOWN;
  for (size_t i = 0; SidebarFunctions[i].op != OP_NULL; i++)
  {
    const struct SidebarFunction *fn = &SidebarFunctions[i];
    if (fn->op == op)
    {
      rc = fn->function(wdata, op);
      break;
    }
  }

  if (rc == FR_UNKNOWN) // Not our function
    return rc;

  const char *result = dispatcher_get_retval_name(rc);
  mutt_debug(LL_DEBUG1, "Handled %s (%d) -> %s\n", opcodes_get_name(op), op, NONULL(result));

  return FR_SUCCESS; // Whatever the outcome, we handled it
}
