// The Theme Editor panel. Modeled on ImGui::ShowStyleEditor (modules/imgui-source/imgui_demo.cpp
// line 8558), which is not in the compiled libs -- imgui_demo.cpp is not built -- so it is
// reimplemented here against the bindings we do have.
//
// Everything in the Sizes and Colors tabs edits app_theme.master, which is DPI-unscaled. The
// single app_theme_bake() at the bottom is what puts the result on screen.

THEME_EDITOR_SAVE_AS_POPUP :: "Save Theme As##theme_editor";

theme_editor_save_as_modal_shown :: () -> bool {
  return ImGui.IsPopupOpen(to_c_string(THEME_EDITOR_SAVE_AS_POPUP,, temp));
}

app_style_editor_ui :: () {
  if !app.show_style_editor  return;
  using ImGui;

  SetNextWindowSize(imgui_scale(Vector2.{560, 680}), .FirstUseEver);

  title := ifx app_theme.dirty then "Theme Editor *###ThemeEditor" else "Theme Editor###ThemeEditor";
  push_imgui_window(title, p_open=*app.show_style_editor);

  changed := false;

  style := *app_theme.master;   // the unscaled master, NOT GetStyle()
  ref   := *app_theme.ref;
  live  := GetStyle();          // only for widget metrics and the font controls

  // master is unscaled, so a one-pixel border is literally 1.0 here.
  DEFAULT_BORDER_SIZE :: 1.0;
  MAX_BORDER_SIZE     :: 2.0;

  PushItemWidth(GetWindowWidth() * 0.5); defer PopItemWidth();

  theme_editor_theme_section();

  SeparatorText("General");
  ShowFontSelector("Fonts##theme");

  // The font fields are per-user and per-monitor rather than part of a theme, so they are
  // edited on the live style directly, the same way the Debug Panel does it.
  if DragFloat("FontSizeBase", *live.FontSizeBase, 0.2, 8, 64, "%.0f", .AlwaysClamp) {
    live._NextFrameFontSizeBase = live.FontSizeBase;
  }
  if IsItemDeactivatedAfterEdit()  app_save_user_settings_file_and_toast("font size");
  DragFloat("FontScaleMain", *live.FontScaleMain, DEFAULT_FONT_SCALE_INCREMENT, FONT_SCALE_MIN, FONT_SCALE_MAX, flags = .AlwaysClamp);
  if IsItemDeactivatedAfterEdit()  app_save_user_settings_file_and_toast("font size");

  if SliderFloat("FrameRounding", *style.FrameRounding, 0, 12, "%.0f") {
    style.GrabRounding = style.FrameRounding;   // keep grabs matching frames, as the demo does
    changed = true;
  }
  {
    border := style.WindowBorderSize > 0;
    if Checkbox("WindowBorder", *border) { style.WindowBorderSize = ifx border then DEFAULT_BORDER_SIZE else 0.0; changed = true; }
  }
  SameLine();
  {
    border := style.FrameBorderSize > 0;
    if Checkbox("FrameBorder", *border) { style.FrameBorderSize = ifx border then DEFAULT_BORDER_SIZE else 0.0; changed = true; }
  }
  SameLine();
  {
    border := style.PopupBorderSize > 0;
    if Checkbox("PopupBorder", *border) { style.PopupBorderSize = ifx border then DEFAULT_BORDER_SIZE else 0.0; changed = true; }
  }

  if Button("Save Ref")  ref.* = style.*;
  SameLine();
  if Button("Revert Ref") { style.* = ref.*; changed = true; }
  SameLine();
  ButtonTooltip("Save/Revert against a scratch copy held in memory only. Use Save to write the theme to disk.");

  SeparatorText("Details");
  if BeginTabBar("##theme_tabs") {
    defer EndTabBar();

    if BeginTabItem("Sizes") {
      changed |= theme_editor_sizes_tab(style, MAX_BORDER_SIZE);
      EndTabItem();
    }

    if BeginTabItem("Colors") {
      changed |= theme_editor_colors_tab(style, ref, live);
      EndTabItem();
    }

    if BeginTabItem("Palette") {
      changed |= theme_editor_palette_tab();
      EndTabItem();
    }

    if BeginTabItem("Rendering") {
      changed |= theme_editor_rendering_tab(style);
      EndTabItem();
    }
  }

  if changed {
    theme_sanitize_style(style);     // a Ctrl+click typed value bypasses the sliders' ranges
    app_theme.dirty = true;
    app_theme_bake(app.win_scale);   // once, at the end, so the frame stays self-consistent
  }
}

// ---------------------------------------------------------------- theme picker

theme_editor_theme_section :: () {
  using ImGui;

  SeparatorText("Theme");

  // ImGui wants a **u8; the registry holds Jai strings, so rebuild the array each frame in temp.
  items := NewArray(app_theme.entries.count, *u8,, temp);
  for app_theme.entries  items[it_index] = to_c_string(it.name,, temp);

  // A copy: the index moves only once the theme has loaded, or Save would write the theme still on
  // screen into the file that failed.
  selected := app_theme.current_index;
  if items.count > 0 && Combo("Theme", *selected, items.data, cast(s32) items.count) {
    if app_theme_apply_index(selected) {
      app_save_user_settings_file_and_toast(tprint("theme %", app_theme.entries[selected].name));
    } else {
      toast_show(.Error, "Could not load theme %; see the Event Log", app_theme.entries[selected].name);
    }
  }

  // Snapshot rather than hold the *Theme_Entry: Save and Rescan below refresh the registry,
  // which frees the entry names and can reallocate the array out from under us.
  current_name := APP_DEFAULT_THEME_NAME;
  current_path := "";
  is_builtin   := true;
  {
    entry := app_theme_current();
    if entry {
      current_name = copy_string(entry.name,, temp);
      current_path = copy_string(entry.path,, temp);
      is_builtin   = entry.source == .Builtin;
    }
  }

  BeginDisabled(is_builtin);
  if Button("Save")  app_theme_save_current();
  SameLine();
  if Button("Reload")  app_theme_reload_current();
  EndDisabled();

  SameLine();
  if Button("Save As...") {
    // Seed the name box with the current theme so overwriting is one keystroke away.
    n := min(current_name.count, app_theme.save_as_buffer.count - 1);
    memcpy(app_theme.save_as_buffer.data, current_name.data, n);
    app_theme.save_as_buffer[n] = 0;
    imgui_show_modal(THEME_EDITOR_SAVE_AS_POPUP);
  }

  SameLine();
  if Button("Copy") {
    clipboard_set_text(app_theme_to_string(*app_theme.master, *app_theme.palette, current_name, .Default));
    app_theme_set_status(tprint("Copied theme % to the clipboard.", current_name), is_error = false);
  }
  ButtonTooltip("Copy the whole theme file to the clipboard.");

  SameLine();
  if Button("Rescan") {
    app_theme_refresh_registry();
    toast_show(.Success, "Found % themes", app_theme.entries.count);
  }
  ButtonTooltip(tprint("Re-read %", app_themes_dir()));

  SameLine();
  if Button("Open Folder")  app_theme_open_folder();
  ButtonTooltip(app_themes_dir());

  SameLine();
  BeginDisabled(is_builtin);
  if Button("Open File")  app_theme_open_current_file();
  EndDisabled();
  if !is_builtin  ButtonTooltip(current_path);

  theme_editor_save_as_modal();

  if app_theme.status.count {
    color := ifx app_theme.status_is_error then app_theme.palette.error else app_theme.palette.dim;
    TextColoredAlt(color, app_theme.status);
  }
}

theme_editor_save_as_modal :: () {
  using ImGui;

  if !BeginPopupModal(THEME_EDITOR_SAVE_AS_POPUP, null, .AlwaysAutoResize)  return;
  defer EndPopup();

  Text("Save to %", app_themes_dir());
  Spacing();

  SetNextItemWidth(imgui_scale(320.0));
  submitted := InputText("Name", app_theme.save_as_buffer.data,
    cast(u64) app_theme.save_as_buffer.count, .EnterReturnsTrue);

  if IsWindowAppearing()  SetKeyboardFocusHere(-1);

  Spacing();
  if Button("Save") || submitted {
    name := to_string(app_theme.save_as_buffer.data);
    if app_theme_save_as(name)  CloseCurrentPopup();
  }
  SameLine();
  if Button("Cancel")  CloseCurrentPopup();
}

// ---------------------------------------------------------------- tabs

theme_editor_sizes_tab :: (style: *ImGui.Style, max_border_size: float) -> bool {
  using ImGui;
  changed := false;

  SeparatorText("Main");
  changed |= SliderFloat2("WindowPadding",     *style.WindowPadding.component,     0, 20, "%.0f");
  changed |= SliderFloat2("FramePadding",      *style.FramePadding.component,      0, 20, "%.0f");
  changed |= SliderFloat2("ItemSpacing",       *style.ItemSpacing.component,       0, 20, "%.0f");
  changed |= SliderFloat2("ItemInnerSpacing",  *style.ItemInnerSpacing.component,  0, 20, "%.0f");
  changed |= SliderFloat2("TouchExtraPadding", *style.TouchExtraPadding.component, 0, 10, "%.0f");
  changed |= SliderFloat ("IndentSpacing",     *style.IndentSpacing,               0, 30, "%.0f");
  changed |= SliderFloat ("GrabMinSize",       *style.GrabMinSize,                 1, 20, "%.0f");

  SeparatorText("Borders");
  changed |= SliderFloat("WindowBorderSize", *style.WindowBorderSize, 0, max_border_size, "%.0f");
  changed |= SliderFloat("ChildBorderSize",  *style.ChildBorderSize,  0, max_border_size, "%.0f");
  changed |= SliderFloat("PopupBorderSize",  *style.PopupBorderSize,  0, max_border_size, "%.0f");
  changed |= SliderFloat("FrameBorderSize",  *style.FrameBorderSize,  0, max_border_size, "%.0f");
  changed |= SliderFloat("ActiveWindowBorderSize", *app_theme.palette.active_window_border_size, 0, 6, "%.1f");

  SeparatorText("Rounding");
  changed |= SliderFloat("WindowRounding", *style.WindowRounding, 0, 12, "%.0f");
  changed |= SliderFloat("ChildRounding",  *style.ChildRounding,  0, 12, "%.0f");
  changed |= SliderFloat("FrameRounding",  *style.FrameRounding,  0, 12, "%.0f");
  changed |= SliderFloat("PopupRounding",  *style.PopupRounding,  0, 12, "%.0f");
  changed |= SliderFloat("GrabRounding",   *style.GrabRounding,   0, 12, "%.0f");

  SeparatorText("Scrollbar");
  changed |= SliderFloat("ScrollbarSize",     *style.ScrollbarSize,     1, 20, "%.0f");
  changed |= SliderFloat("ScrollbarRounding", *style.ScrollbarRounding, 0, 12, "%.0f");
  changed |= SliderFloat("ScrollbarPadding",  *style.ScrollbarPadding,  0, 10, "%.0f");

  SeparatorText("Tabs");
  changed |= SliderFloat("TabBorderSize",      *style.TabBorderSize,      0, max_border_size, "%.0f");
  changed |= SliderFloat("TabBarBorderSize",   *style.TabBarBorderSize,   0, max_border_size, "%.0f");
  changed |= SliderFloat("TabBarOverlineSize", *style.TabBarOverlineSize, 0, max(3.0, max_border_size), "%.0f");
  changed |= DragFloat  ("TabMinWidthBase",    *style.TabMinWidthBase,    0.5, 1, 500, "%.0f");
  changed |= DragFloat  ("TabMinWidthShrink",  *style.TabMinWidthShrink,  0.5, 1, 500, "%.0f");
  changed |= SliderFloat("TabRounding",        *style.TabRounding,        0, 12, "%.0f");

  SeparatorText("Tables");
  changed |= SliderFloat2("CellPadding", *style.CellPadding.component, 0, 20, "%.0f");
  changed |= SliderAngle ("TableAngledHeadersAngle", *style.TableAngledHeadersAngle, -50, 50);
  changed |= SliderFloat2("TableAngledHeadersTextAlign", *style.TableAngledHeadersTextAlign.component, 0, 1, "%.2f");

  SeparatorText("Trees");
  {
    // TreeLinesFlags is one of three whole values, not a free bitfield, so it gets a combo.
    OPTIONS :: ImGui.TreeNodeFlags.[.DrawLinesNone, .DrawLinesFull, .DrawLinesToNodes];
    if BeginCombo("TreeLinesFlags", to_c_string(theme_tree_lines_name(style.TreeLinesFlags),, temp)) {
      for OPTIONS {
        if Selectable(to_c_string(theme_tree_lines_name(it),, temp), style.TreeLinesFlags == it) {
          style.TreeLinesFlags = it;
          changed = true;
        }
      }
      EndCombo();
    }
  }
  changed |= SliderFloat("TreeLinesSize",     *style.TreeLinesSize,     0, max_border_size, "%.0f");
  changed |= SliderFloat("TreeLinesRounding", *style.TreeLinesRounding, 0, 12, "%.0f");

  SeparatorText("Windows");
  changed |= SliderFloat2("WindowTitleAlign", *style.WindowTitleAlign.component, 0, 1, "%.2f");
  changed |= SliderFloat ("WindowBorderHoverPadding", *style.WindowBorderHoverPadding, 1, 20, "%.0f");
  changed |= SliderFloat2("WindowMinSize", *style.WindowMinSize.component, 1, 200, "%.0f");
  {
    // ImGuiDir_None is -1, so shift into the combo's 0-based index space and back.
    position := (cast(s32) style.WindowMenuButtonPosition) + 1;
    if Combo("WindowMenuButtonPosition", *position, "None\0Left\0Right\0") {
      style.WindowMenuButtonPosition = cast(ImGui.Dir)(position - 1);
      changed = true;
    }
  }

  SeparatorText("Widgets");
  changed |= SliderFloat("ColorMarkerSize", *style.ColorMarkerSize, 0, 8, "%.0f");
  {
    position := cast(s32) style.ColorButtonPosition;
    if Combo("ColorButtonPosition", *position, "Left\0Right\0") {
      style.ColorButtonPosition = cast(ImGui.Dir) position;
      changed = true;
    }
  }
  changed |= SliderFloat2("ButtonTextAlign",        *style.ButtonTextAlign.component,     0, 1, "%.2f");
  changed |= SliderFloat2("SelectableTextAlign",    *style.SelectableTextAlign.component, 0, 1, "%.2f");
  changed |= SliderFloat ("SeparatorSize",          *style.SeparatorSize,           0, 10, "%.0f");
  changed |= SliderFloat ("SeparatorTextBorderSize", *style.SeparatorTextBorderSize, 0, 10, "%.0f");
  changed |= SliderFloat2("SeparatorTextAlign",     *style.SeparatorTextAlign.component,   0, 1,  "%.2f");
  changed |= SliderFloat2("SeparatorTextPadding",   *style.SeparatorTextPadding.component, 0, 40, "%.0f");
  changed |= SliderFloat ("LogSliderDeadzone",      *style.LogSliderDeadzone, 0, 12, "%.0f");
  changed |= SliderFloat ("ImageRounding",          *style.ImageRounding,     0, 12, "%.0f");
  changed |= SliderFloat ("ImageBorderSize",        *style.ImageBorderSize,   0, max_border_size, "%.0f");

  SeparatorText("Docking");
  changed |= Checkbox   ("DockingNodeHasCloseButton", *style.DockingNodeHasCloseButton);
  changed |= SliderFloat("DockingSeparatorSize",      *style.DockingSeparatorSize, 0, 12, "%.0f");

  SeparatorText("Tooltips");
  changed |= theme_editor_hover_flags("HoverFlagsForTooltipMouse", *style.HoverFlagsForTooltipMouse);
  changed |= theme_editor_hover_flags("HoverFlagsForTooltipNav",   *style.HoverFlagsForTooltipNav);

  SeparatorText("Misc");
  changed |= SliderFloat2("DisplayWindowPadding",   *style.DisplayWindowPadding.component,   0, 30, "%.0f");
  changed |= SliderFloat2("DisplaySafeAreaPadding", *style.DisplaySafeAreaPadding.component, 0, 30, "%.0f");
  changed |= SliderFloat ("MouseCursorScale",       *style.MouseCursorScale, 0.5, 4, "%.2f");

  return changed;
}

theme_editor_hover_flags :: (label: string, flags: *ImGui.HoveredFlags) -> bool {
  using ImGui;
  if !TreeNodeEx(to_c_string(label,, temp))  return false;
  defer TreePop();

  changed := false;
  as_int := cast(*s32) flags;
  changed |= CheckboxFlags("DelayNone",     as_int, cast(s32) HoveredFlags.DelayNone);
  changed |= CheckboxFlags("DelayShort",    as_int, cast(s32) HoveredFlags.DelayShort);
  changed |= CheckboxFlags("DelayNormal",   as_int, cast(s32) HoveredFlags.DelayNormal);
  changed |= CheckboxFlags("Stationary",    as_int, cast(s32) HoveredFlags.Stationary);
  changed |= CheckboxFlags("NoSharedDelay", as_int, cast(s32) HoveredFlags.NoSharedDelay);
  return changed;
}

theme_tree_lines_name :: (flags: ImGui.TreeNodeFlags) -> string {
  if flags == .DrawLinesNone     return "DrawLinesNone";
  if flags == .DrawLinesFull     return "DrawLinesFull";
  if flags == .DrawLinesToNodes  return "DrawLinesToNodes";
  return "(custom)";
}

theme_editor_colors_tab :: (style: *ImGui.Style, ref: *ImGui.Style, live: *ImGui.Style) -> bool {
  using ImGui;
  changed := false;

  app_theme.color_filter.Draw(*app_theme.color_filter, "Filter colors", GetFontSize() * 16);

  if RadioButton("Opaque", app_theme.alpha_flags == .AlphaOpaque)       app_theme.alpha_flags = .AlphaOpaque;
  SameLine();
  if RadioButton("Alpha", app_theme.alpha_flags == .None)               app_theme.alpha_flags = .None;
  SameLine();
  if RadioButton("Both", app_theme.alpha_flags == .AlphaPreviewHalf)    app_theme.alpha_flags = .AlphaPreviewHalf;
  SameLine();
  ButtonTooltip("Left-click a color square to open the picker, right-click for edit options.");

  SetNextWindowSizeConstraints(ImVec2.{0, GetTextLineHeightWithSpacing() * 10}, ImVec2.{FLOAT32_MAX, FLOAT32_MAX});
  BeginChild("##colors", ImVec2.{0, 0}, .Borders | .NavFlattened, .AlwaysVerticalScrollbar);
  {
    defer EndChild();   // BeginChild must be paired whatever it returned
    PushItemWidth(GetFontSize() * -12);   // negative: window width minus 12em, leaving room on the right
    defer PopItemWidth();

    for i: 0 .. (cast(s32) Col.COUNT) - 1 {
      name := to_string(GetStyleColorName(cast(Col) i));
      if !app_theme.color_filter.PassFilter(*app_theme.color_filter, name)  continue;

      PushID(i);
      defer PopID();

      if Button("?")  DebugFlashStyleColor(cast(Col) i);
      SetItemTooltip("Flash this color wherever it is used.");
      SameLine();

      changed |= ColorEdit4("##color", *style.Colors[i].component, .AlphaBar | app_theme.alpha_flags);

      if style.Colors[i] != ref.Colors[i] {
        SameLine(0, live.ItemInnerSpacing.x);
        if Button("Save")  ref.Colors[i] = style.Colors[i];
        SameLine(0, live.ItemInnerSpacing.x);
        if Button("Revert") { style.Colors[i] = ref.Colors[i]; changed = true; }
      }

      SameLine(0, live.ItemInnerSpacing.x);
      TextUnformatted(name);
    }
  }

  return changed;
}

theme_editor_palette_tab :: () -> bool {
  using ImGui;
  changed := false;

  TextWrapped("Colors the app draws with that have no ImGui style slot. Ported themes fill these from the source theme's editor colors.");
  Spacing();

  pal := *app_theme.palette;
  for member: theme_palette_fields() {
    color := cast(*Vector4) (cast(*u8) pal + member.offset_in_bytes);
    PushID(cast(s32) it_index);
    defer PopID();
    changed |= ColorEdit4(to_c_string(member.name,, temp), *color.component, .AlphaBar | app_theme.alpha_flags);
  }

  return changed;
}

theme_editor_rendering_tab :: (style: *ImGui.Style) -> bool {
  using ImGui;
  changed := false;

  changed |= Checkbox("Anti-aliased lines", *style.AntiAliasedLines);
  changed |= Checkbox("Anti-aliased lines use texture", *style.AntiAliasedLinesUseTex);
  changed |= Checkbox("Anti-aliased fill", *style.AntiAliasedFill);

  PushItemWidth(GetFontSize() * 8);
  defer PopItemWidth();

  if DragFloat("Curve Tessellation Tolerance", *style.CurveTessellationTol, 0.02, 0.1, 10, "%.2f") {
    if style.CurveTessellationTol < 0.1  style.CurveTessellationTol = 0.1;
    changed = true;
  }
  changed |= DragFloat("Circle Tessellation Max Error", *style.CircleTessellationMaxError, 0.005, 0.1, 5, "%.2f", .AlwaysClamp);

  // 0.0 is deliberately out of range: it would make the whole UI invisible with no way back.
  changed |= DragFloat("Global Alpha", *style.Alpha, 0.005, 0.2, 1, "%.2f");
  changed |= DragFloat("Disabled Alpha", *style.DisabledAlpha, 0.005, 0, 1, "%.2f");

  return changed;
}