delta_wordprocessor/App-Events.cppm at main · mxreal64/delta_wordprocessor · GitHub

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// This project is licensed under the GPL-3.0 License. See the LICENSE file for details, or check out <gnu.org>.
// Copyright (C) 2026 mxreal64

module;
#include <SDL3/SDL.h>
#include <SDL3_ttf/SDL_ttf.h>

export module delta.app:events;
import delta.types;
import delta.engine;
import :buffer; //  Internal import of the sibling partition slice
import std;

export class EventController {
public:
    EventController() noexcept = default;

    [[nodiscard]] bool process_input(
        const SDL_Event& event,
        DocumentBuffer& doc,
        selection_span& sel,
        TTF_Font* font,
        const std::vector<LayoutLine>& layout,
        bool& app_running
    ) noexcept {
        bool changed = false;

        if (event.type == SDL_EVENT_QUIT) {
            app_running = false;
            return false;
        }

        if (event.type == SDL_EVENT_TEXT_INPUT) {
            if (sel.start != sel.end) {
                doc.erase_range(sel.start, sel.end - sel.start);
                sel.end = sel.start;
            }
            doc.insert_str(sel.start, event.text.text);
            sel.start += std::strlen(event.text.text);
            sel.end = sel.start;
            changed = true;
        }

        if (event.type == SDL_EVENT_MOUSE_BUTTON_DOWN && event.button.button == SDL_BUTTON_LEFT) {
            sel.active_drag = true;
            sel.start = pixel_coords_to_buffer_index(font, layout, doc.get_raw(), event.button.x, event.button.y);
            sel.end = sel.start;
        }
        if (event.type == SDL_EVENT_MOUSE_MOTION && sel.active_drag) {
            sel.end = pixel_coords_to_buffer_index(font, layout, doc.get_raw(), event.motion.x, event.motion.y);
        }
        if (event.type == SDL_EVENT_MOUSE_BUTTON_UP && event.button.button == SDL_BUTTON_LEFT) {
            sel.active_drag = false;
            if (sel.start > sel.end) std::swap(sel.start, sel.end);
        }

        if (event.type == SDL_EVENT_KEY_DOWN) {
            if (event.key.key == SDLK_ESCAPE) app_running = false;

            if (event.key.key == SDLK_RETURN) {
                if (sel.start != sel.end) {
                    doc.erase_range(sel.start, sel.end - sel.start);
                    sel.end = sel.start;
                }
                doc.insert_str(sel.start, "\n");
                sel.start++; sel.end = sel.start;
                changed = true;
            }

            if (event.key.key == SDLK_BACKSPACE) {
                if (sel.start != sel.end) {
                    doc.erase_range(sel.start, sel.end - sel.start);
                    sel.end = sel.start;
                    changed = true;
                } else if (sel.start > 0) {
                    char target = doc[sel.start - 1];
                    if (target == '\x02' || target == '\x03') {
                        if (sel.start > 1) {
                            doc.erase_range(sel.start - 2, 2); sel.start -= 2;
                        } else {
                            doc.erase_range(sel.start - 1, 1); sel.start--;
                        }
                    } else {
                        doc.erase_range(sel.start - 1, 1); sel.start--;
                    }
                    sel.end = sel.start;
                    changed = true;
                }
            }

            if (event.key.mod & SDL_KMOD_CTRL) {
                if (event.key.key == SDLK_B) { doc.inject_style(sel, '\x02'); changed = true; }
                if (event.key.key == SDLK_I) { doc.inject_style(sel, '\x03'); changed = true; }
            }
        }
        return changed;
    }
};