waylight/src/ImGui.cpp

#include "ImGui.hpp"

#include <algorithm>
#include <cassert>
#include <cctype>
#include <cmath>
#include <format>
#include <string>
#include <string_view>
#include <vector>

#include <raylib.h>

namespace Waylight {

namespace {

struct CodepointSpan {
	u32 codepoint {};
	usize start {};
	usize end {};
};

constexpr inline float px_pos(float x) { return std::floor(x + 0.5f); }
constexpr inline float px_w(float w) { return std::ceil(w); }

constexpr auto utf8_rune_from_first(char const *s) -> u32
{
	u8 b0 = static_cast<u8>(s[0]);
	if (b0 < 0x80)
		return b0;

	if ((b0 & 0xE0) == 0xC0)
		return ((b0 & 0x1F) << 6) | (static_cast<u8>(s[1]) & 0x3F);

	if ((b0 & 0xF0) == 0xE0)
		return ((b0 & 0x0F) << 12) | ((static_cast<u8>(s[1]) & 0x3F) << 6)
		    | (static_cast<u8>(s[2]) & 0x3F);

	if ((b0 & 0xF8) == 0xF0)
		return ((b0 & 0x07) << 18) | ((static_cast<u8>(s[1]) & 0x3F) << 12)
		    | ((static_cast<u8>(s[2]) & 0x3F) << 6)
		    | (static_cast<u8>(s[3]) & 0x3F);

	return 0xFFFD;
}

constexpr auto decode_utf8(std::string_view text) -> std::vector<CodepointSpan>
{
	std::vector<CodepointSpan> spans;
	usize i = 0;
	spans.reserve(text.size());

	while (i < text.size()) {
		u8 b = static_cast<u8>(text[i]);
		usize len = 1;

		if (b < 0x80)
			len = 1;
		else if ((b & 0xE0) == 0xC0)
			len = 2;
		else if ((b & 0xF0) == 0xE0)
			len = 3;
		else if ((b & 0xF8) == 0xF0)
			len = 4;

		if (i + len > text.size())
			len = 1;

		u32 cp = utf8_rune_from_first(text.data() + i);
		spans.push_back({ cp, i, i + len });
		i += len;
	}

	return spans;
}

auto encode_utf8(u32 cp) -> std::string
{
	char buf[5] = { 0, 0, 0, 0, 0 };
	int len = 0;
	if (cp <= 0x7F) {
		buf[len++] = static_cast<char>(cp);
	} else if (cp <= 0x7FF) {
		buf[len++] = static_cast<char>(0xC0 | (cp >> 6));
		buf[len++] = static_cast<char>(0x80 | (cp & 0x3F));
	} else if (cp <= 0xFFFF) {
		if (cp >= 0xD800 && cp <= 0xDFFF)
			return {};
		buf[len++] = static_cast<char>(0xE0 | (cp >> 12));
		buf[len++] = static_cast<char>(0x80 | ((cp >> 6) & 0x3F));
		buf[len++] = static_cast<char>(0x80 | (cp & 0x3F));
	} else if (cp <= 0x10FFFF) {
		buf[len++] = static_cast<char>(0xF0 | (cp >> 18));
		buf[len++] = static_cast<char>(0x80 | ((cp >> 12) & 0x3F));
		buf[len++] = static_cast<char>(0x80 | ((cp >> 6) & 0x3F));
		buf[len++] = static_cast<char>(0x80 | (cp & 0x3F));
	} else {
		return {};
	}
	return std::string(buf, len);
}

auto rune_index_for_byte(std::string_view text, usize byte_offset) -> int
{
	auto spans { decode_utf8(text) };
	int idx = 0;
	for (auto const &span : spans) {
		if (span.start >= byte_offset)
			break;
		idx++;
	}
	if (byte_offset >= text.size())
		idx = static_cast<int>(spans.size());
	return idx;
}

auto clamp_preedit_index(int value, usize text_size) -> usize
{
	if (value < 0)
		return 0;
	auto const as_size { static_cast<usize>(value) };
	return std::min(as_size, text_size);
}

constexpr float HORIZONTAL_PADDING = 6.0f;
constexpr float VERTICAL_PADDING = 4.0f;
constexpr double CARET_BLINK_INTERVAL = 0.5;
constexpr float CARET_DESCENT_FRACTION = 0.25f;

} // namespace

ImGui::ImGui(std::shared_ptr<TextRenderer> text_renderer)
    : m_text_renderer(text_renderer)
{
}

void ImGui::begin(u32 const rune, bool ctrl, bool shift,
    std::string_view const clipboard,
    std::function<void(std::string_view const &)> clipboard_set)
{
	m_rune = rune;
	m_ctrl = ctrl;
	m_shift = shift;
	m_clipboard = clipboard;
	m_clipboard_set = clipboard_set;
}

void ImGui::end()
{
	m_rune = false;
	m_ctrl = false;
	m_shift = false;
	m_clipboard = {};
	m_clipboard_set = nullptr;
}

void ImGui::set_font(FontHandle font) { m_font = font; }

auto ImGui::focused_text_input() const -> std::optional<usize>
{
	if (m_focused_id == 0)
		return std::nullopt;
	return m_focused_id;
}

auto ImGui::text_input_surrounding(usize id, std::pmr::string const &str) const
    -> std::optional<TextInputSurrounding>
{
	auto it { m_ti_states.find(id) };
	if (it == m_ti_states.end())
		return std::nullopt;
	TextInputSurrounding info;
	info.text.assign(str.data(), str.size());
	info.caret_byte = std::min(it->second.caret_byte, str.size());
	info.cursor = static_cast<int>(info.caret_byte);
	info.anchor = static_cast<int>(info.caret_byte);
	return info;
}

auto ImGui::text_input_cursor(usize id) const -> std::optional<TextInputCursor>
{
	auto it { m_ti_states.find(id) };
	if (it == m_ti_states.end())
		return std::nullopt;
	TextInputCursor cursor;
	cursor.rect = it->second.caret_rect;
	cursor.visible
	    = it->second.caret_visible && !it->second.preedit_cursor_hidden;
	return cursor;
}

void ImGui::ime_commit_text(std::pmr::string &str, std::string_view text)
{
	if (m_focused_id == 0)
		return;
	auto it { m_ti_states.find(m_focused_id) };
	if (it == m_ti_states.end())
		return;
	auto &state { it->second };
	usize insert_pos = std::min(state.caret_byte, str.size());
	if (!text.empty())
		str.insert(insert_pos, text);
	state.caret_byte = insert_pos + text.size();
	std::string_view const view(str.data(), str.size());
	state.current_rune_idx = rune_index_for_byte(view, state.caret_byte);
	state.caret_timer = 0.0;
	state.caret_visible = true;
	state.external_change = true;
}

void ImGui::ime_delete_surrounding(
    std::pmr::string &str, usize before, usize after)
{
	if (m_focused_id == 0)
		return;
	auto it { m_ti_states.find(m_focused_id) };
	if (it == m_ti_states.end())
		return;
	auto &state { it->second };
	usize caret_byte { std::min(state.caret_byte, str.size()) };
	usize start { before > caret_byte ? 0 : caret_byte - before };
	usize end { std::min(caret_byte + after, str.size()) };
	if (end > start) {
		str.erase(start, end - start);
		state.caret_byte = start;
		std::string_view const view(str.data(), str.size());
		state.current_rune_idx = rune_index_for_byte(view, state.caret_byte);
		state.caret_timer = 0.0;
		state.caret_visible = true;
		state.external_change = true;
	}
}

void ImGui::ime_set_preedit(std::string text, int cursor_begin, int cursor_end)
{
	if (m_focused_id == 0)
		return;
	auto it { m_ti_states.find(m_focused_id) };
	if (it == m_ti_states.end())
		return;
	auto &state { it->second };
	state.preedit_text = std::move(text);
	state.preedit_cursor_hidden = (cursor_begin == -1 && cursor_end == -1);
	usize const size = state.preedit_text.size();
	if (state.preedit_cursor_hidden) {
		state.preedit_cursor_begin = 0;
		state.preedit_cursor_end = 0;
	} else {
		auto begin_clamped { clamp_preedit_index(cursor_begin, size) };
		auto end_clamped { clamp_preedit_index(cursor_end, size) };
		state.preedit_cursor_begin = static_cast<int>(begin_clamped);
		state.preedit_cursor_end = static_cast<int>(end_clamped);
	}
	state.preedit_active
	    = !state.preedit_text.empty() || !state.preedit_cursor_hidden;
	if (state.preedit_active) {
		state.caret_timer = 0.0;
		state.caret_visible = !state.preedit_cursor_hidden;
	}
}

void ImGui::ime_clear_preedit()
{
	if (m_focused_id == 0)
		return;
	auto it { m_ti_states.find(m_focused_id) };
	if (it == m_ti_states.end())
		return;
	auto &state { it->second };
	state.preedit_text.clear();
	state.preedit_cursor_begin = 0;
	state.preedit_cursor_end = 0;
	state.preedit_active = false;
	state.preedit_cursor_hidden = false;
	state.caret_visible = true;
	state.caret_timer = 0.0;
}

size_t utf8_length(std::string_view const &s)
{
	size_t count = std::count_if(
	    s.begin(), s.end(), [](auto const &c) { return (c & 0xC0) != 0x80; });
	return count;
}

auto ImGui::text_input(usize id, std::pmr::string &str, Rectangle rec,
    TextInputOptions options) -> std::bitset<2>
{
	assert(id != 0);
	assert(
	    m_font.has_value() && "ImGui font must be set before using text input");

	bool submitted { false };
	bool changed { false };

	auto &state { m_ti_states[id] };
	assert(!options.multiline && "Multiline not yet implemented.");

	if (m_focused_id == 0)
		m_focused_id = id;

	if (style().font_size > rec.height) {
		TraceLog(LOG_WARNING,
		    std::format("Text size for text input {} is bigger than height ({} "
		                "> {}). Clipping will occur.",
		        id, style().font_size, rec.height)
		        .c_str());
	}

	std::string_view str_view(str.data(), str.size());
	auto spans { decode_utf8(str_view) };

	auto is_space = [](u32 cp) -> bool {
		if (cp == '\n' || cp == '\r' || cp == '\t' || cp == '\v' || cp == '\f')
			return true;
		if (cp <= 0x7F)
			return std::isspace(static_cast<unsigned char>(cp)) != 0;
		return false;
	};

	auto clamp_cursor = [&]() -> usize {
		int const max_idx = static_cast<int>(spans.size());
		state.current_rune_idx = std::clamp(state.current_rune_idx, 0, max_idx);
		if (state.current_rune_idx == max_idx)
			return str.size();
		return spans[(usize)state.current_rune_idx].start;
	};

	usize caret_byte = clamp_cursor();

	auto refresh_spans = [&]() {
		str_view = std::string_view(str.data(), str.size());
		spans = decode_utf8(str_view);
		caret_byte = clamp_cursor();
	};

	auto erase_range = [&](usize byte_begin, usize byte_end) {
		if (byte_end > byte_begin && byte_begin < str.size()) {
			str.erase(byte_begin, byte_end - byte_begin);
			changed = true;
		}
	};

	auto selection_range_bytes
	    = [&](int a_idx, int b_idx) -> std::pair<usize, usize> {
		int lo = std::max(0, std::min(a_idx, b_idx));
		int hi = std::max(0, std::max(a_idx, b_idx));
		usize byte_begin
		    = (lo >= (int)spans.size()) ? str.size() : spans[(usize)lo].start;
		usize byte_end
		    = (hi >= (int)spans.size()) ? str.size() : spans[(usize)hi].start;
		return { byte_begin, byte_end };
	};

	auto erase_selection_if_any = [&]() -> bool {
		if (!state.has_selection(state.current_rune_idx))
			return false;
		auto [b, e] = selection_range_bytes(
		    state.sel_anchor_idx, state.current_rune_idx);
		if (e > b) {
			str.erase(b, e - b);
			changed = true;
			refresh_spans();
			state.current_rune_idx = rune_index_for_byte(str_view, b);
			state.clear_selection();
		}
		return true;
	};

	auto move_left_word = [&]() {
		while (state.current_rune_idx > 0
		    && is_space(spans[(usize)(state.current_rune_idx - 1)].codepoint))
			state.current_rune_idx--;
		while (state.current_rune_idx > 0
		    && !is_space(spans[(usize)(state.current_rune_idx - 1)].codepoint))
			state.current_rune_idx--;
	};
	auto move_right_word = [&]() {
		while (state.current_rune_idx < (int)spans.size()
		    && is_space(spans[(usize)state.current_rune_idx].codepoint))
			state.current_rune_idx++;
		while (state.current_rune_idx < (int)spans.size()
		    && !is_space(spans[(usize)state.current_rune_idx].codepoint))
			state.current_rune_idx++;
	};

	bool caret_activity = false;

	if (m_focused_id == id && m_rune != 0) {
		bool request_refresh = false;

		auto handle_backspace = [&]() {
			if (state.current_rune_idx <= 0
			    || state.current_rune_idx > (int)spans.size())
				return;
			if (m_ctrl) {
				int idx = state.current_rune_idx, scan = idx - 1;
				while (scan >= 0 && is_space(spans[(usize)scan].codepoint))
					scan--;
				while (scan >= 0 && !is_space(spans[(usize)scan].codepoint))
					scan--;
				int start_idx = std::max(scan + 1, 0);
				usize b = spans[(usize)start_idx].start;
				usize e = (idx >= (int)spans.size()) ? str.size()
				                                     : spans[(usize)idx].start;
				erase_range(b, e);
				state.current_rune_idx = start_idx;
			} else {
				auto const &prev = spans[(usize)(state.current_rune_idx - 1)];
				erase_range(prev.start, prev.end);
				state.current_rune_idx--;
			}
			request_refresh = true;
		};

		auto handle_delete = [&]() {
			if (state.current_rune_idx < 0
			    || state.current_rune_idx >= (int)spans.size()) {
				if (!m_ctrl)
					return;
			}
			int idx = state.current_rune_idx;
			if (m_ctrl) {
				int scan = idx;
				while (scan < (int)spans.size()
				    && is_space(spans[(usize)scan].codepoint))
					scan++;
				while (scan < (int)spans.size()
				    && !is_space(spans[(usize)scan].codepoint))
					scan++;
				usize b = (idx < (int)spans.size()) ? spans[(usize)idx].start
				                                    : str.size();
				usize e = (scan < (int)spans.size()) ? spans[(usize)scan].start
				                                     : str.size();
				erase_range(b, e);
			} else if (idx < (int)spans.size()) {
				auto const &curr = spans[(usize)idx];
				erase_range(curr.start, curr.end);
			}
			request_refresh = true;
		};

		bool extend = m_shift;

		switch (m_rune) {
		case 1: // Left
			if (!extend)
				state.clear_selection();
			if (state.current_rune_idx > 0) {
				if (extend && state.sel_anchor_idx == -1)
					state.sel_anchor_idx = state.current_rune_idx;
				if (m_ctrl)
					move_left_word();
				else
					state.current_rune_idx--;
				caret_byte = clamp_cursor();
			}
			break;
		case 4: // Right
			if (!extend)
				state.clear_selection();
			if (state.current_rune_idx < (int)spans.size()) {
				if (extend && state.sel_anchor_idx == -1)
					state.sel_anchor_idx = state.current_rune_idx;
				if (m_ctrl)
					move_right_word();
				else
					state.current_rune_idx++;
				caret_byte = clamp_cursor();
			}
			break;
		case 3: // Up -> home
			if (!extend)
				state.clear_selection();
			if (extend && state.sel_anchor_idx == -1)
				state.sel_anchor_idx = state.current_rune_idx;
			state.current_rune_idx = 0;
			caret_byte = clamp_cursor();
			break;
		case 2: // Down -> end
			if (!extend)
				state.clear_selection();
			if (extend && state.sel_anchor_idx == -1)
				state.sel_anchor_idx = state.current_rune_idx;
			state.current_rune_idx = (int)spans.size();
			caret_byte = clamp_cursor();
			break;
		case 8: // Backspace
			if (erase_selection_if_any()) {
				request_refresh = true;
				break;
			}
			handle_backspace();
			break;
		case 0x7F: // Delete
			if (erase_selection_if_any()) {
				request_refresh = true;
				break;
			}
			handle_delete();
			break;
		case 'a':
			if (m_ctrl) {
				state.sel_anchor_idx = 0;
				state.current_rune_idx = (int)spans.size();
				request_refresh = true;
				break;
			}
			[[fallthrough]];
		case 'c':
			if (m_ctrl) {
				if (state.has_selection(state.current_rune_idx)
				    && m_clipboard_set) {
					auto [b, e] = selection_range_bytes(
					    state.sel_anchor_idx, state.current_rune_idx);
					m_clipboard_set(std::string_view(str.data() + b, e - b));
				}
				break;
			}
			[[fallthrough]];
		case 'x':
			if (m_ctrl) {
				if (state.has_selection(state.current_rune_idx)
				    && m_clipboard_set) {
					auto [b, e] = selection_range_bytes(
					    state.sel_anchor_idx, state.current_rune_idx);
					m_clipboard_set(std::string_view(str.data() + b, e - b));
					str.erase(b, e - b);
					changed = true;
					request_refresh = true;
					refresh_spans();
					state.current_rune_idx = rune_index_for_byte(str_view, b);
					state.clear_selection();
				}
				break;
			}
			[[fallthrough]];
		case 'v':
			if (m_ctrl && !m_clipboard.empty()) {
				erase_selection_if_any();
				if (!options.multiline) {
					std::string clip2;
					clip2.reserve(m_clipboard.size());
					std::copy_if(m_clipboard.begin(), m_clipboard.end(),
					    clip2.begin(),
					    [](char ch) { return ch != '\n' && ch != '\r'; });
					str.insert(caret_byte, clip2);
					state.current_rune_idx += (int)utf8_length(clip2);
				} else {
					str.insert(caret_byte, m_clipboard);
					state.current_rune_idx += (int)utf8_length(m_clipboard);
				}
				changed = true;
				request_refresh = true;
				break;
			} else {
				goto insert_printable;
			}
			break;
		case '\r':
		case '\n':
			if (options.multiline) {
				erase_selection_if_any();
				auto encoded { encode_utf8('\n') };
				if (!encoded.empty()) {
					str.insert(caret_byte, encoded);
					state.current_rune_idx++;
					changed = true;
					request_refresh = true;
				}
			} else {
				submitted = true;
			}
			break;
		default:
		insert_printable:
			if (m_rune >= 0x20) {
				erase_selection_if_any();
				auto encoded { encode_utf8(m_rune) };
				if (!encoded.empty()) {
					str.insert(caret_byte, encoded);
					state.current_rune_idx++;
					changed = true;
					request_refresh = true;
				}
			}
			break;
		}

		if (request_refresh)
			refresh_spans();
		else
			caret_byte = clamp_cursor();
		caret_activity = true;
	}

	state.caret_byte = caret_byte;

	double const dt = (double)GetFrameTime();
	if (m_focused_id == id) {
		if (state.preedit_active && state.preedit_cursor_hidden) {
			state.caret_visible = false;
			state.caret_timer = 0.0;
		} else if (caret_activity) {
			state.caret_timer = 0.0;
			state.caret_visible = true;
		} else {
			if (state.caret_timer == 0.0)
				state.caret_visible = true;
			state.caret_timer += dt;
			if (state.caret_timer >= CARET_BLINK_INTERVAL) {
				int toggles = (int)(state.caret_timer / CARET_BLINK_INTERVAL);
				state.caret_timer
				    = std::fmod(state.caret_timer, CARET_BLINK_INTERVAL);
				if (toggles % 2 == 1)
					state.caret_visible = !state.caret_visible;
			}
		}
	} else {
		state.caret_visible = false;
		state.caret_timer = 0.0;
	}

	Color const bg_col { 16, 16, 16, 100 };
	Color const border_col { 220, 220, 220, 180 };
	DrawRectangleRec(rec, bg_col);
	DrawRectangleLinesEx(rec, 1.0f, border_col);

	float const text_top = rec.y + VERTICAL_PADDING;
	float const baseline_y = text_top + style().font_size;
	float const max_caret_h
	    = std::max(0.0f, rec.height - 2.0f * VERTICAL_PADDING);
	float caret_height = style().font_size * (1.0f + CARET_DESCENT_FRACTION);
	caret_height = std::min(
	    caret_height, max_caret_h > 0.0f ? max_caret_h : caret_height);
	if (caret_height <= 0.0f)
		caret_height = style().font_size;
	float caret_top = baseline_y - style().font_size;
	float const min_top = rec.y + VERTICAL_PADDING;
	float const max_top = rec.y + rec.height - VERTICAL_PADDING - caret_height;
	caret_top = std::clamp(caret_top, min_top, max_top);
	float caret_bottom = caret_top + caret_height;
	float const desired_bottom
	    = baseline_y + style().font_size * CARET_DESCENT_FRACTION;
	if (caret_bottom < desired_bottom) {
		float const adjust = desired_bottom - caret_bottom;
		caret_top = std::min(caret_top + adjust, max_top);
		caret_bottom = caret_top + caret_height;
	}
	state.cursor_position.y = caret_top;

	float const available_width
	    = std::max(0.0f, rec.width - 2.0f * HORIZONTAL_PADDING);
	float const base_y = px_pos(baseline_y);

	int const font_px = (int)style().font_size;

	Vector2 prefix_metrics { 0.0f, 0.0f };
	{
		std::string_view prefix(str.data(), caret_byte);
		if (m_text_renderer)
			prefix_metrics
			    = m_text_renderer->measure_text(*m_font, prefix, font_px);
	}

	Vector2 caret_preedit_metrics { 0.0f, 0.0f };
	bool const has_preedit = state.preedit_active
	    && (!state.preedit_text.empty() || !state.preedit_cursor_hidden);
	if (has_preedit && m_text_renderer) {
		auto pe_end = clamp_preedit_index(
		    state.preedit_cursor_end, state.preedit_text.size());
		caret_preedit_metrics = m_text_renderer->measure_text(*m_font,
		    std::string_view(state.preedit_text.data(), (usize)pe_end),
		    font_px);
	}

	Vector2 full_metrics { 0.0f, 0.0f };
	{
		std::string display;
		display.reserve(
		    str.size() + (has_preedit ? state.preedit_text.size() : 0));
		display.append(std::string_view(str.data(), caret_byte));
		if (has_preedit)
			display.append(state.preedit_text);
		display.append(
		    std::string_view(str.data() + caret_byte, str.size() - caret_byte));
		if (m_text_renderer)
			full_metrics = m_text_renderer->measure_text(*m_font,
			    std::string_view(display.data(), display.size()), font_px);
	}

	float caret_offset = prefix_metrics.x + caret_preedit_metrics.x;
	state.cursor_position.x = caret_offset;

	if (full_metrics.x <= available_width) {
		state.scroll_offset.x = 0.0f;
	} else {
		float &scroll = state.scroll_offset.x;
		float caret_local = caret_offset - scroll;
		float const pad = 8.0f;
		if (caret_local > available_width - pad)
			scroll = caret_offset - (available_width - pad);
		else if (caret_local < pad)
			scroll = caret_offset - pad;
		scroll = std::clamp(
		    scroll, 0.0f, std::max(0.0f, full_metrics.x - available_width));
	}
	state.scroll_offset.y = 0.0f;

	float const origin = rec.x + HORIZONTAL_PADDING - state.scroll_offset.x;

	BeginScissorMode(rec.x, rec.y, rec.width, rec.height);
	{
		if (m_font.has_value() && m_text_renderer) {
			Color const &text_color = style().text_color;

			std::string display;
			display.reserve(
			    str.size() + (has_preedit ? state.preedit_text.size() : 0));
			display.append(std::string_view(str.data(), caret_byte));
			if (has_preedit)
				display.append(state.preedit_text);
			display.append(std::string_view(
			    str.data() + caret_byte, str.size() - caret_byte));

			m_text_renderer->draw_text(*m_font,
			    std::string_view(display.data(), display.size()),
			    { origin, base_y }, font_px, text_color);

			if (state.has_selection(state.current_rune_idx)) {
				auto [sb, se] = selection_range_bytes(
				    state.sel_anchor_idx, state.current_rune_idx);

				Vector2 sel_prefix = m_text_renderer->measure_text(
				    *m_font, std::string_view(str.data(), sb), font_px);
				Vector2 sel_width = m_text_renderer->measure_text(*m_font,
				    std::string_view(str.data() + sb, se - sb), font_px);

				Rectangle sel_rect { std::floor(origin + sel_prefix.x + 0.5f),
					std::floor(caret_top + 0.5f),
					std::max(1.0f, sel_width.x) + 1,
					std::max(1.0f, std::round(caret_height)) };
				DrawRectangleRec(sel_rect, style().selection_color);

				m_text_renderer->draw_text(*m_font,
				    std::string_view(str.data() + sb, se - sb),
				    { origin + sel_prefix.x, base_y }, font_px,
				    style().selection_text_color);
			}

			if (m_focused_id == id && state.caret_visible) {
				float const caret_x = std::floor(origin + caret_offset + 0.5f);
				Vector2 const p0 { caret_x, std::floor(caret_top + 0.5f) };
				Vector2 const p1 { caret_x,
					std::floor((caret_top + caret_height) + 0.5f) };
				DrawLineV(p0, p1, text_color);
			}
		}
	}
	EndScissorMode();

	if (state.external_change) {
		changed = true;
		state.external_change = false;
	}

	return std::bitset<2> { static_cast<unsigned long long>(
		(submitted ? 1 : 0) | (changed ? 2 : 0)) };
}

auto ImGui::list_view(usize id, Rectangle bounds, usize elements,
    std::function<Vector2(usize i)> draw_cb, ListViewOptions options) -> bool
{
	auto const &state { m_lv_states[id] };

	bool submitted { false };

	m_next_lv_next = false;
	m_next_lv_previous = false;
	m_next_lv_clear = false;

	BeginScissorMode(bounds.x, bounds.y, bounds.width, bounds.height);

	EndScissorMode();

	m_prev_lv_selected_item = state.selected_item;

	return submitted;
}

} // namespace Waylight