panopainter/src/app_core/canvas_tool_ui.h

#pragma once

#include "foundation/result.h"

namespace pp::app {

enum class CanvasToolOperation {
    select_mode,
    toggle_picking,
    toggle_touch_lock,
};

enum class CanvasToolMode {
    draw,
    erase,
    line,
    camera,
    grid,
    copy,
    cut,
    fill,
    mask_free,
    mask_line,
    flood_fill,
};

enum class CanvasToolTransformAction {
    none,
    copy,
    cut,
};

struct CanvasToolPlan {
    CanvasToolOperation operation = CanvasToolOperation::select_mode;
    CanvasToolMode mode = CanvasToolMode::draw;
    CanvasToolTransformAction transform_action = CanvasToolTransformAction::none;
    bool selects_toolbar_button = false;
    bool updates_canvas_mode = false;
    bool toggles_picking = false;
    bool toggles_touch_lock = false;
    bool requires_draw_mode = false;
    bool no_op = false;
};

struct CanvasToolButtonState {
    CanvasToolMode mode = CanvasToolMode::draw;
    bool pick_active = false;
    bool touch_lock_active = false;
    bool pen_active = false;
    bool erase_active = false;
    bool line_active = false;
    bool camera_active = false;
    bool grid_active = false;
    bool copy_active = false;
    bool cut_active = false;
    bool fill_active = false;
    bool mask_free_active = false;
    bool mask_line_active = false;
    bool flood_fill_active = false;
};

class CanvasToolServices {
public:
    virtual ~CanvasToolServices() = default;

    virtual void select_toolbar_button(CanvasToolMode mode) = 0;
    virtual void set_transform_action(CanvasToolTransformAction action) = 0;
    virtual void set_canvas_mode(CanvasToolMode mode) = 0;
    virtual void toggle_picking() = 0;
    virtual void toggle_touch_lock() = 0;
};

[[nodiscard]] inline constexpr CanvasToolTransformAction transform_action_for_mode(CanvasToolMode mode) noexcept
{
    if (mode == CanvasToolMode::copy) {
        return CanvasToolTransformAction::copy;
    }
    if (mode == CanvasToolMode::cut) {
        return CanvasToolTransformAction::cut;
    }
    return CanvasToolTransformAction::none;
}

[[nodiscard]] inline constexpr CanvasToolPlan plan_canvas_tool_select(CanvasToolMode mode) noexcept
{
    CanvasToolPlan plan;
    plan.operation = CanvasToolOperation::select_mode;
    plan.mode = mode;
    plan.transform_action = transform_action_for_mode(mode);
    plan.selects_toolbar_button = true;
    plan.updates_canvas_mode = true;
    return plan;
}

[[nodiscard]] inline constexpr CanvasToolPlan plan_canvas_tool_pick_toggle(bool current_mode_is_draw) noexcept
{
    CanvasToolPlan plan;
    plan.operation = CanvasToolOperation::toggle_picking;
    plan.mode = CanvasToolMode::draw;
    plan.requires_draw_mode = true;
    plan.toggles_picking = current_mode_is_draw;
    plan.no_op = !current_mode_is_draw;
    return plan;
}

[[nodiscard]] inline constexpr CanvasToolPlan plan_canvas_tool_touch_lock_toggle() noexcept
{
    CanvasToolPlan plan;
    plan.operation = CanvasToolOperation::toggle_touch_lock;
    plan.toggles_touch_lock = true;
    return plan;
}

[[nodiscard]] inline constexpr CanvasToolButtonState plan_canvas_tool_button_state(
    CanvasToolMode mode,
    bool picking,
    bool touch_lock) noexcept
{
    CanvasToolButtonState state;
    state.mode = mode;
    state.pick_active = mode == CanvasToolMode::draw && picking;
    state.touch_lock_active = touch_lock;
    state.pen_active = mode == CanvasToolMode::draw;
    state.erase_active = mode == CanvasToolMode::erase;
    state.line_active = mode == CanvasToolMode::line;
    state.camera_active = mode == CanvasToolMode::camera;
    state.grid_active = mode == CanvasToolMode::grid;
    state.copy_active = mode == CanvasToolMode::copy;
    state.cut_active = mode == CanvasToolMode::cut;
    state.fill_active = mode == CanvasToolMode::fill;
    state.mask_free_active = mode == CanvasToolMode::mask_free;
    state.mask_line_active = mode == CanvasToolMode::mask_line;
    state.flood_fill_active = mode == CanvasToolMode::flood_fill;
    return state;
}

[[nodiscard]] inline pp::foundation::Status execute_canvas_tool_plan(
    const CanvasToolPlan& plan,
    CanvasToolServices& services)
{
    switch (plan.operation) {
    case CanvasToolOperation::select_mode:
        if (!plan.selects_toolbar_button || !plan.updates_canvas_mode) {
            return pp::foundation::Status::invalid_argument("canvas tool select plan must select toolbar and update mode");
        }
        if (plan.transform_action != transform_action_for_mode(plan.mode)) {
            return pp::foundation::Status::invalid_argument("canvas tool select plan has mismatched transform action");
        }
        services.select_toolbar_button(plan.mode);
        if (plan.transform_action != CanvasToolTransformAction::none) {
            services.set_transform_action(plan.transform_action);
        }
        services.set_canvas_mode(plan.mode);
        return pp::foundation::Status::success();

    case CanvasToolOperation::toggle_picking:
        if (!plan.requires_draw_mode) {
            return pp::foundation::Status::invalid_argument("canvas pick plan must require draw mode");
        }
        if (plan.no_op) {
            return pp::foundation::Status::success();
        }
        if (!plan.toggles_picking) {
            return pp::foundation::Status::invalid_argument("canvas pick plan must toggle picking or be a no-op");
        }
        services.toggle_picking();
        return pp::foundation::Status::success();

    case CanvasToolOperation::toggle_touch_lock:
        if (!plan.toggles_touch_lock || plan.no_op) {
            return pp::foundation::Status::invalid_argument("canvas touch-lock plan must toggle touch lock");
        }
        services.toggle_touch_lock();
        return pp::foundation::Status::success();
    }

    return pp::foundation::Status::invalid_argument("unknown canvas tool operation");
}

} // namespace pp::app