text: // This is an open source non-commercial project. Dear PVS-Studio, please check
  // it. PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
  
  #include <assert.h>
  #include <stddef.h>
  #include <stdint.h>
  #include <stdbool.h>
  
  #include "nvim/vim.h"
  #include "nvim/ui.h"
  #include "nvim/memory.h"
  #include "nvim/map.h"
  #include "nvim/msgpack_rpc/channel.h"
  #include "nvim/api/ui.h"
  #include "nvim/api/private/defs.h"
  #include "nvim/api/private/helpers.h"
  #include "nvim/popupmnu.h"
  #include "nvim/cursor_shape.h"
  #include "nvim/highlight.h"
  
  #ifdef INCLUDE_GENERATED_DECLARATIONS
  # include "api/ui.c.generated.h"
  # include "ui_events_remote.generated.h"
  #endif
  
  typedef struct {
    uint64_t channel_id;
    Array buffer;
  
    int hl_id;  // current higlight for legacy put event
    Integer cursor_row, cursor_col;  // Intended visibule cursor position
  
    // Position of legacy cursor, used both for drawing and visible user cursor.
    Integer client_row, client_col;
  } UIData;
  
  static PMap(uint64_t) *connected_uis = NULL;
  
  void remote_ui_init(void)
    FUNC_API_NOEXPORT
  {
    connected_uis = pmap_new(uint64_t)();
  }
  
  void remote_ui_disconnect(uint64_t channel_id)
    FUNC_API_NOEXPORT
  {
    UI *ui = pmap_get(uint64_t)(connected_uis, channel_id);
    if (!ui) {
      return;
    }
    UIData *data = ui->data;
    api_free_array(data->buffer);  // Destroy pending screen updates.
    pmap_del(uint64_t)(connected_uis, channel_id);
    xfree(ui->data);
    ui->data = NULL;  // Flag UI as "stopped".
    ui_detach_impl(ui);
    xfree(ui);
  }
  
  /// Wait until ui has connected on stdio channel.
  void remote_ui_wait_for_attach(void)
    FUNC_API_NOEXPORT
  {
    Channel *channel = find_channel(CHAN_STDIO);
    if (!channel) {
      // this function should only be called in --embed mode, stdio channel
      // can be assumed.
      abort();
    }
  
    LOOP_PROCESS_EVENTS_UNTIL(&main_loop, channel->events, -1,
                              pmap_has(uint64_t)(connected_uis, CHAN_STDIO));
  }
  
  void nvim_ui_attach(uint64_t channel_id, Integer width, Integer height,
                      Dictionary options, Error *err)
    FUNC_API_SINCE(1) FUNC_API_REMOTE_ONLY
  {
    if (pmap_has(uint64_t)(connected_uis, channel_id)) {
      api_set_error(err, kErrorTypeException,
                    "UI already attached to channel: %" PRId64, channel_id);
      return;
    }
  
    if (width <= 0 || height <= 0) {
      api_set_error(err, kErrorTypeValidation,
                    "Expected width > 0 and height > 0");
      return;
    }
    UI *ui = xcalloc(1, sizeof(UI));
    ui->width = (int)width;
    ui->height = (int)height;
    ui->rgb = true;
    ui->grid_resize = remote_ui_grid_resize;
    ui->grid_clear = remote_ui_grid_clear;
    ui->grid_cursor_goto = remote_ui_grid_cursor_goto;
    ui->mode_info_set = remote_ui_mode_info_set;
    ui->update_menu = remote_ui_update_menu;
    ui->busy_start = remote_ui_busy_start;
    ui->busy_stop = remote_ui_busy_stop;
    ui->mouse_on = remote_ui_mouse_on;
    ui->mouse_off = remote_ui_mouse_off;
    ui->mode_change = remote_ui_mode_change;
    ui->grid_scroll = remote_ui_grid_scroll;
    ui->hl_attr_define = remote_ui_hl_attr_define;
    ui->raw_line = remote_ui_raw_line;
    ui->bell = remote_ui_bell;
    ui->visual_bell = remote_ui_visual_bell;
    ui->default_colors_set = remote_ui_default_colors_set;
    ui->flush = remote_ui_flush;
    ui->suspend = remote_ui_suspend;
    ui->set_title = remote_ui_set_title;
    ui->set_icon = remote_ui_set_icon;
    ui->option_set = remote_ui_option_set;
    ui->win_scroll_over_start = remote_ui_win_scroll_over_start;
    ui->win_scroll_over_reset = remote_ui_win_scroll_over_reset;
    ui->event = remote_ui_event;
    ui->inspect = remote_ui_inspect;
  
    memset(ui->ui_ext, 0, sizeof(ui->ui_ext));
  
    for (size_t i = 0; i < options.size; i++) {
      ui_set_option(ui, true, options.items[i].key, options.items[i].value, err);
      if (ERROR_SET(err)) {
        xfree(ui);
        return;
      }
    }
  
    if (ui->ui_ext[kUIHlState] || ui->ui_ext[kUIMultigrid]) {
      ui->ui_ext[kUILinegrid] = true;
    }
  
    UIData *data = xmalloc(sizeof(UIData));
    data->channel_id = channel_id;
    data->buffer = (Array)ARRAY_DICT_INIT;
    data->hl_id = 0;
    data->client_col = -1;
    ui->data = data;
  
    pmap_put(uint64_t)(connected_uis, channel_id, ui);
    ui_attach_impl(ui);
  }
  
  /// @deprecated
  void ui_attach(uint64_t channel_id, Integer width, Integer height,
                 Boolean enable_rgb, Error *err)
  {
    Dictionary opts = ARRAY_DICT_INIT;
    PUT(opts, "rgb", BOOLEAN_OBJ(enable_rgb));
    nvim_ui_attach(channel_id, width, height, opts, err);
    api_free_dictionary(opts);
  }
  
  void nvim_ui_detach(uint64_t channel_id, Error *err)
    FUNC_API_SINCE(1) FUNC_API_REMOTE_ONLY
  {
    if (!pmap_has(uint64_t)(connected_uis, channel_id)) {
      api_set_error(err, kErrorTypeException,
                    "UI not attached to channel: %" PRId64, channel_id);
      return;
    }
    remote_ui_disconnect(channel_id);
  }
  
  
  void nvim_ui_try_resize(uint64_t channel_id, Integer width,
                          Integer height, Error *err)
    FUNC_API_SINCE(1) FUNC_API_REMOTE_ONLY
  {
    if (!pmap_has(uint64_t)(connected_uis, channel_id)) {
      api_set_error(err, kErrorTypeException,
                    "UI not attached to channel: %" PRId64, channel_id);
      return;
    }
  
    if (width <= 0 || height <= 0) {
      api_set_error(err, kErrorTypeValidation,
                    "Expected width > 0 and height > 0");
      return;
    }
  
    UI *ui = pmap_get(uint64_t)(connected_uis, channel_id);
    ui->width = (int)width;
    ui->height = (int)height;
    ui_refresh();
  }
  
  void nvim_ui_set_option(uint64_t channel_id, String name,
                          Object value, Error *error)
    FUNC_API_SINCE(1) FUNC_API_REMOTE_ONLY
  {
    if (!pmap_has(uint64_t)(connected_uis, channel_id)) {
      api_set_error(error, kErrorTypeException,
                    "UI not attached to channel: %" PRId64, channel_id);
      return;
    }
    UI *ui = pmap_get(uint64_t)(connected_uis, channel_id);
  
    ui_set_option(ui, false, name, value, error);
  }
  
  static void ui_set_option(UI *ui, bool init, String name, Object value,
                            Error *error)
  {
    if (strequal(name.data, "rgb")) {
      if (value.type != kObjectTypeBoolean) {
        api_set_error(error, kErrorTypeValidation, "rgb must be a Boolean");
        return;
      }
      ui->rgb = value.data.boolean;
      // A little drastic, but only legacy uis need to use this option
      if (!init) {
        ui_refresh();
      }
      return;
    }
  
    // LEGACY: Deprecated option, use `ext_cmdline` instead.
    bool is_popupmenu = strequal(name.data, "popupmenu_external");
  
    for (UIExtension i = 0; i < kUIExtCount; i++) {
      if (strequal(name.data, ui_ext_names[i])
          || (i == kUIPopupmenu && is_popupmenu)) {
        if (value.type != kObjectTypeBoolean) {
          api_set_error(error, kErrorTypeValidation, "%s must be a Boolean",
                        name.data);
          return;
        }
        bool boolval = value.data.boolean;
        if (!init && i == kUILinegrid && boolval != ui->ui_ext[i]) {
          // There shouldn't be a reason for an UI to do this ever
          // so explicitly don't support this.
          api_set_error(error, kErrorTypeValidation,
                        "ext_linegrid option cannot be changed");
        }
        ui->ui_ext[i] = boolval;
        if (!init) {
          ui_set_ext_option(ui, i, boolval);
        }
        return;
      }
    }
  
    api_set_error(error, kErrorTypeValidation, "No such UI option: %s",
                  name.data);
  }
  
  /// Tell Nvim to resize a grid. Triggers a grid_resize event with the requested
  /// grid size or the maximum size if it exceeds size limits.
  ///
  /// On invalid grid handle, fails with error.
  ///
  /// @param grid    The handle of the grid to be changed.
  /// @param width   The new requested width.
  /// @param height  The new requested height.
  void nvim_ui_try_resize_grid(uint64_t channel_id, Integer grid, Integer width,
                               Integer height, Error *error)
    FUNC_API_SINCE(6) FUNC_API_REMOTE_ONLY
  {
    if (!pmap_has(uint64_t)(connected_uis, channel_id)) {
      api_set_error(error, kErrorTypeException,
                    "UI not attached to channel: %" PRId64, channel_id);
      return;
    }
  
    ui_grid_resize((handle_T)grid, (int)width, (int)height, error);
  }
  
  /// Pushes data into UI.UIData, to be consumed later by remote_ui_flush().
  static void push_call(UI *ui, const char *name, Array args)
  {
    Array call = ARRAY_DICT_INIT;
    UIData *data = ui->data;
  
    // To optimize data transfer(especially for "put"), we bundle adjacent
    // calls to same method together, so only add a new call entry if the last
    // method call is different from "name"
    if (kv_size(data->buffer)) {
      call = kv_A(data->buffer, kv_size(data->buffer) - 1).data.array;
    }
  
    if (!kv_size(call) || strcmp(kv_A(call, 0).data.string.data, name)) {
      call = (Array)ARRAY_DICT_INIT;
      ADD(data->buffer, ARRAY_OBJ(call));
      ADD(call, STRING_OBJ(cstr_to_string(name)));
    }
  
    ADD(call, ARRAY_OBJ(args));
    kv_A(data->buffer, kv_size(data->buffer) - 1).data.array = call;
  }
  
  static void remote_ui_grid_clear(UI *ui, Integer grid)
  {
    Array args = ARRAY_DICT_INIT;
    if (ui->ui_ext[kUILinegrid]) {
      ADD(args, INTEGER_OBJ(grid));
    }
    const char *name = ui->ui_ext[kUILinegrid] ? "grid_clear" : "clear";
    push_call(ui, name, args);
  }
  
  static void remote_ui_grid_resize(UI *ui, Integer grid,
                                    Integer width, Integer height)
  {
    Array args = ARRAY_DICT_INIT;
    if (ui->ui_ext[kUILinegrid]) {
      ADD(args, INTEGER_OBJ(grid));
    }
    ADD(args, INTEGER_OBJ(width));
    ADD(args, INTEGER_OBJ(height));
    const char *name = ui->ui_ext[kUILinegrid] ? "grid_resize" : "resize";
    push_call(ui, name, args);
  }
  
  static void remote_ui_grid_scroll(UI *ui, Integer grid, Integer top,
                                    Integer bot, Integer left, Integer right,
                                    Integer rows, Integer cols)
  {
    if (ui->ui_ext[kUILinegrid]) {
      Array args = ARRAY_DICT_INIT;
      ADD(args, INTEGER_OBJ(grid));
      ADD(args, INTEGER_OBJ(top));
      ADD(args, INTEGER_OBJ(bot));
      ADD(args, INTEGER_OBJ(left));
      ADD(args, INTEGER_OBJ(right));
      ADD(args, INTEGER_OBJ(rows));
      ADD(args, INTEGER_OBJ(cols));
      push_call(ui, "grid_scroll", args);
    } else {
      Array args = ARRAY_DICT_INIT;
      ADD(args, INTEGER_OBJ(top));
      ADD(args, INTEGER_OBJ(bot-1));
      ADD(args, INTEGER_OBJ(left));
      ADD(args, INTEGER_OBJ(right-1));
      push_call(ui, "set_scroll_region", args);
  
      args = (Array)ARRAY_DICT_INIT;
      ADD(args, INTEGER_OBJ(rows));
      push_call(ui, "scroll", args);
  
      // some clients have "clear" being affected by scroll region,
      // so reset it.
      args = (Array)ARRAY_DICT_INIT;
      ADD(args, INTEGER_OBJ(0));
      ADD(args, INTEGER_OBJ(ui->height-1));
      ADD(args, INTEGER_OBJ(0));
      ADD(args, INTEGER_OBJ(ui->width-1));
      push_call(ui, "set_scroll_region", args);
    }
  }
  
  static void remote_ui_default_colors_set(UI *ui, Integer rgb_fg,
                                           Integer rgb_bg, Integer rgb_sp,
                                           Integer cterm_fg, Integer cterm_bg)
  {
    Array args = ARRAY_DICT_INIT;
    ADD(args, INTEGER_OBJ(rgb_fg));
    ADD(args, INTEGER_OBJ(rgb_bg));
    ADD(args, INTEGER_OBJ(rgb_sp));
    ADD(args, INTEGER_OBJ(cterm_fg));
    ADD(args, INTEGER_OBJ(cterm_bg));
    push_call(ui, "default_colors_set", args);
  
    // Deprecated
    if (!ui->ui_ext[kUILinegrid]) {
      args = (Array)ARRAY_DICT_INIT;
      ADD(args, INTEGER_OBJ(ui->rgb ? rgb_fg : cterm_fg - 1));
      push_call(ui, "update_fg", args);
  
      args = (Array)ARRAY_DICT_INIT;
      ADD(args, INTEGER_OBJ(ui->rgb ? rgb_bg : cterm_bg - 1));
      push_call(ui, "update_bg", args);
  
      args = (Array)ARRAY_DICT_INIT;
      ADD(args, INTEGER_OBJ(ui->rgb ? rgb_sp : -1));
      push_call(ui, "update_sp", args);
    }
  }
  
  static void remote_ui_hl_attr_define(UI *ui, Integer id, HlAttrs rgb_attrs,
                                       HlAttrs cterm_attrs, Array info)
  {
    if (!ui->ui_ext[kUILinegrid]) {
      return;
    }
    Array args = ARRAY_DICT_INIT;
  
    ADD(args, INTEGER_OBJ(id));
    ADD(args, DICTIONARY_OBJ(hlattrs2dict(rgb_attrs, true)));
    ADD(args, DICTIONARY_OBJ(hlattrs2dict(cterm_attrs, false)));
  
    if (ui->ui_ext[kUIHlState]) {
      ADD(args, ARRAY_OBJ(copy_array(info)));
    } else {
      ADD(args, ARRAY_OBJ((Array)ARRAY_DICT_INIT));
    }
  
    push_call(ui, "hl_attr_define", args);
  }
  
  static void remote_ui_highlight_set(UI *ui, int id)
  {
    Array args = ARRAY_DICT_INIT;
    UIData *data = ui->data;
  
  
    if (data->hl_id == id) {
      return;
    }
    data->hl_id = id;
    Dictionary hl = hlattrs2dict(syn_attr2entry(id), ui->rgb);
  
    ADD(args, DICTIONARY_OBJ(hl));
    push_call(ui, "highlight_set", args);
  }
  
  /// "true" cursor used only for input focus
  static void remote_ui_grid_cursor_goto(UI *ui, Integer grid, Integer row,
                                         Integer col)
  {
    if (ui->ui_ext[kUILinegrid]) {
      Array args = ARRAY_DICT_INIT;
      ADD(args, INTEGER_OBJ(grid));
      ADD(args, INTEGER_OBJ(row));
      ADD(args, INTEGER_OBJ(col));
      push_call(ui, "grid_cursor_goto", args);
    } else {
      UIData *data = ui->data;
      data->cursor_row = row;
      data->cursor_col = col;
      remote_ui_cursor_goto(ui, row, col);
    }
  }
  
  /// emulated cursor used both for drawing and for input focus
  static void remote_ui_cursor_goto(UI *ui, Integer row, Integer col)
  {
    UIData *data = ui->data;
    if (data->client_row == row && data->client_col == col) {
      return;
    }
    data->client_row = row;
    data->client_col = col;
    Array args = ARRAY_DICT_INIT;
    ADD(args, INTEGER_OBJ(row));
    ADD(args, INTEGER_OBJ(col));
    push_call(ui, "cursor_goto", args);
  }
  
  static void remote_ui_put(UI *ui, const char *cell)
  {
    UIData *data = ui->data;
    data->client_col++;
    Array args = ARRAY_DICT_INIT;
    ADD(args, STRING_OBJ(cstr_to_string(cell)));
    push_call(ui, "put", args);
  }
  
  static void remote_ui_raw_line(UI *ui, Integer grid, Integer row,
                                 Integer startcol, Integer endcol,
                                 Integer clearcol, Integer clearattr,
                                 LineFlags flags, const schar_T *chunk,
                                 const sattr_T *attrs)
  {
    UIData *data = ui->data;
    if (ui->ui_ext[kUILinegrid]) {
      Array args = ARRAY_DICT_INIT;
      ADD(args, INTEGER_OBJ(grid));
      ADD(args, INTEGER_OBJ(row));
      ADD(args, INTEGER_OBJ(startcol));
      Array cells = ARRAY_DICT_INIT;
      int repeat = 0;
      size_t ncells = (size_t)(endcol-startcol);
      int last_hl = -1;
      for (size_t i = 0; i < ncells; i++) {
        repeat++;
        if (i == ncells-1 || attrs[i] != attrs[i+1]
            || STRCMP(chunk[i], chunk[i+1])) {
          Array cell = ARRAY_DICT_INIT;
          ADD(cell, STRING_OBJ(cstr_to_string((const char *)chunk[i])));
          if (attrs[i] != last_hl || repeat > 1) {
            ADD(cell, INTEGER_OBJ(attrs[i]));
            last_hl = attrs[i];
          }
          if (repeat > 1) {
            ADD(cell, INTEGER_OBJ(repeat));
          }
          ADD(cells, ARRAY_OBJ(cell));
          repeat = 0;
        }
      }
      if (endcol < clearcol) {
        Array cell = ARRAY_DICT_INIT;
        ADD(cell, STRING_OBJ(cstr_to_string(" ")));
        ADD(cell, INTEGER_OBJ(clearattr));
        ADD(cell, INTEGER_OBJ(clearcol-endcol));
        ADD(cells, ARRAY_OBJ(cell));
      }
      ADD(args, ARRAY_OBJ(cells));
  
      push_call(ui, "grid_line", args);
    } else {
      for (int i = 0; i < endcol-startcol; i++) {
        remote_ui_cursor_goto(ui, row, startcol+i);
        remote_ui_highlight_set(ui, attrs[i]);
        remote_ui_put(ui, (const char *)chunk[i]);
        if (utf_ambiguous_width(utf_ptr2char(chunk[i]))) {
          data->client_col = -1;  // force cursor update
        }
      }
      if (endcol < clearcol) {
        remote_ui_cursor_goto(ui, row, endcol);
        remote_ui_highlight_set(ui, (int)clearattr);
        // legacy eol_clear was only ever used with cleared attributes
        // so be on the safe side
        if (clearattr == 0 && clearcol == Columns) {
          Array args = ARRAY_DICT_INIT;
          push_call(ui, "eol_clear", args);
        } else {
          for (Integer c = endcol; c < clearcol; c++) {
            remote_ui_put(ui, " ");
          }
        }
      }
    }
  }
  
  static void remote_ui_flush(UI *ui)
  {
    UIData *data = ui->data;
    if (data->buffer.size > 0) {
      if (!ui->ui_ext[kUILinegrid]) {
        remote_ui_cursor_goto(ui, data->cursor_row, data->cursor_col);
      }
      push_call(ui, "flush", (Array)ARRAY_DICT_INIT);
      rpc_send_event(data->channel_id, "redraw", data->buffer);
      data->buffer = (Array)ARRAY_DICT_INIT;
    }
  }
  
  static Array translate_contents(UI *ui, Array contents)
  {
    Array new_contents = ARRAY_DICT_INIT;
    for (size_t i = 0; i < contents.size; i++) {
      Array item = contents.items[i].data.array;
      Array new_item = ARRAY_DICT_INIT;
      int attr = (int)item.items[0].data.integer;
      if (attr) {
        Dictionary rgb_attrs = hlattrs2dict(syn_attr2entry(attr), ui->rgb);
        ADD(new_item, DICTIONARY_OBJ(rgb_attrs));
      } else {
        ADD(new_item, DICTIONARY_OBJ((Dictionary)ARRAY_DICT_INIT));
      }
      ADD(new_item, copy_object(item.items[1]));
      ADD(new_contents, ARRAY_OBJ(new_item));
    }
    return new_contents;
  }
  
  static Array translate_firstarg(UI *ui, Array args)
  {
    Array new_args = ARRAY_DICT_INIT;
    Array contents = args.items[0].data.array;
  
    ADD(new_args, ARRAY_OBJ(translate_contents(ui, contents)));
    for (size_t i = 1; i < args.size; i++) {
      ADD(new_args, copy_object(args.items[i]));
    }
    return new_args;
  }
  
  static void remote_ui_event(UI *ui, char *name, Array args, bool *args_consumed)
  {
    if (!ui->ui_ext[kUILinegrid]) {
      // the representation of highlights in cmdline changed, translate back
      // never consumes args
      if (strequal(name, "cmdline_show")) {
        Array new_args = translate_firstarg(ui, args);
        push_call(ui, name, new_args);
        return;
      } else if (strequal(name, "cmdline_block_show")) {
        Array new_args = ARRAY_DICT_INIT;
        Array block = args.items[0].data.array;
        Array new_block = ARRAY_DICT_INIT;
        for (size_t i = 0; i < block.size; i++) {
          ADD(new_block,
              ARRAY_OBJ(translate_contents(ui, block.items[i].data.array)));
        }
        ADD(new_args, ARRAY_OBJ(new_block));
        push_call(ui, name, new_args);
        return;
      } else if (strequal(name, "cmdline_block_append")) {
        Array new_args = translate_firstarg(ui, args);
        push_call(ui, name, new_args);
        return;
      }
    }
  
    Array my_args = ARRAY_DICT_INIT;
    // Objects are currently single-reference
    // make a copy, but only if necessary
    if (*args_consumed) {
      for (size_t i = 0; i < args.size; i++) {
        ADD(my_args, copy_object(args.items[i]));
      }
    } else {
      my_args = args;
      *args_consumed = true;
    }
    push_call(ui, name, my_args);
  }
  
  static void remote_ui_inspect(UI *ui, Dictionary *info)
  {
    UIData *data = ui->data;
    PUT(*info, "chan", INTEGER_OBJ((Integer)data->channel_id));
  }
  