//
//	TextEditComponent.cpp
//
//	Component for editing text fields in menus.
//

#include "components/TextEditComponent.h"

#include "resources/Font.h"
#include "utils/StringUtil.h"

#define TEXT_PADDING_HORIZ 10
#define TEXT_PADDING_VERT 2

#define CURSOR_REPEAT_START_DELAY 500
#define CURSOR_REPEAT_SPEED 28 // Lower is faster.

TextEditComponent::TextEditComponent(
		Window* window)
		: GuiComponent(window),
		mBox(window, ":/textinput_ninepatch.png"),
		mFocused(false),
		mScrollOffset(0.0f, 0.0f),
		mCursor(0), mEditing(false),
		mFont(Font::get(FONT_SIZE_MEDIUM, FONT_PATH_LIGHT)),
		mCursorRepeatDir(0)
{
	addChild(&mBox);
	onFocusLost();
	setSize(4096, mFont->getHeight() + TEXT_PADDING_VERT);
}

void TextEditComponent::onFocusGained()
{
	mFocused = true;
	mBox.setImagePath(":/textinput_ninepatch_active.png");
}

void TextEditComponent::onFocusLost()
{
	mFocused = false;
	mBox.setImagePath(":/textinput_ninepatch.png");
}

void TextEditComponent::onSizeChanged()
{
	mBox.fitTo(mSize, Vector3f::Zero(), Vector2f(-34, -32 - TEXT_PADDING_VERT));
	onTextChanged(); // Wrap point probably changed.
}

void TextEditComponent::setValue(const std::string& val)
{
	mText = val;
	mTextOrig = val;
	onTextChanged();
}

std::string TextEditComponent::getValue() const
{
	return mText;
}

void TextEditComponent::textInput(const char* text)
{
	if (mEditing) {
		mCursorRepeatDir = 0;
		if (text[0] == '\b') {
			if (mCursor > 0) {
				size_t newCursor = Utils::String::prevCursor(mText, mCursor);
				mText.erase(mText.begin() + newCursor, mText.begin() + mCursor);
				mCursor = (unsigned int)newCursor;
			}
		}
		else {
			mText.insert(mCursor, text);
			mCursor += (unsigned int)strlen(text);
		}
	}

	onTextChanged();
	onCursorChanged();
}

void TextEditComponent::startEditing()
{
	SDL_StartTextInput();
	mEditing = true;
	updateHelpPrompts();
}

void TextEditComponent::stopEditing()
{
	SDL_StopTextInput();
	mEditing = false;
	updateHelpPrompts();
}

bool TextEditComponent::input(InputConfig* config, Input input)
{
	bool const cursor_left = (config->getDeviceId() != DEVICE_KEYBOARD &&
			config->isMappedLike("left", input)) || (config->getDeviceId() == DEVICE_KEYBOARD &&
			input.id == SDLK_LEFT);
	bool const cursor_right = (config->getDeviceId() != DEVICE_KEYBOARD &&
			config->isMappedLike("right", input)) || (config->getDeviceId() == DEVICE_KEYBOARD &&
			input.id == SDLK_RIGHT);

	if (input.value == 0) {
		if (cursor_left || cursor_right)
			mCursorRepeatDir = 0;

		return false;
	}

	if ((config->isMappedTo("a", input) || (config->getDeviceId() == DEVICE_KEYBOARD &&
			input.id == SDLK_RETURN)) && mFocused && !mEditing) {
		startEditing();
		return true;
	}

	if (mEditing) {
		if (config->getDeviceId() == DEVICE_KEYBOARD && input.id == SDLK_RETURN) {
			if (isMultiline())
				textInput("\n");
			else
				stopEditing();

			return true;
		}

		// Stop editing.
		if ((config->getDeviceId() == DEVICE_KEYBOARD && input.id == SDLK_ESCAPE) ||
				(config->getDeviceId() != DEVICE_KEYBOARD && config->isMappedTo("b", input))) {
			mTextOrig = mText;
			stopEditing();
			return true;
		}

		if (config->getDeviceId() != DEVICE_KEYBOARD && config->isMappedLike("up", input)) {
			// TODO.
		}
		else if (config->getDeviceId() != DEVICE_KEYBOARD && config->isMappedLike("down", input)) {
			// TODO.
		}
		else if (config->getDeviceId() != DEVICE_KEYBOARD && config->isMappedTo("y", input)) {
			textInput("\b");
		}
		else if (cursor_left || cursor_right) {
			mCursorRepeatDir = cursor_left ? -1 : 1;
			mCursorRepeatTimer = -(CURSOR_REPEAT_START_DELAY - CURSOR_REPEAT_SPEED);
			moveCursor(mCursorRepeatDir);
		}
		else if (config->getDeviceId() == DEVICE_KEYBOARD) {
			switch (input.id) {
			case SDLK_HOME:
				setCursor(0);
				break;

			case SDLK_END:
				setCursor(std::string::npos);
				break;

			case SDLK_DELETE:
				if (mCursor < mText.length()) {
					// Fake as Backspace one char to the right.
					moveCursor(1);
					textInput("\b");
				}
				break;
			}
		}
		// Consume all input when editing text.
		return true;
	}

	return false;
}

void TextEditComponent::update(int deltaTime)
{
	updateCursorRepeat(deltaTime);
	GuiComponent::update(deltaTime);
}

void TextEditComponent::updateCursorRepeat(int deltaTime)
{
	if (mCursorRepeatDir == 0)
		return;

	mCursorRepeatTimer += deltaTime;
	while (mCursorRepeatTimer >= CURSOR_REPEAT_SPEED) {
		moveCursor(mCursorRepeatDir);
		mCursorRepeatTimer -= CURSOR_REPEAT_SPEED;
	}
}

void TextEditComponent::moveCursor(int amt)
{
	mCursor = (unsigned int)Utils::String::moveCursor(mText, mCursor, amt);
	onCursorChanged();
}

void TextEditComponent::setCursor(size_t pos)
{
	if (pos == std::string::npos)
		mCursor = (unsigned int)mText.length();
	else
		mCursor = (int)pos;

	moveCursor(0);
}

void TextEditComponent::onTextChanged()
{
	std::string wrappedText = (isMultiline() ?
			mFont->wrapText(mText, getTextAreaSize().x()) : mText);
	mTextCache = std::unique_ptr<TextCache>
			(mFont->buildTextCache(wrappedText, 0, 0, 0x77777700 | getOpacity()));

	if (mCursor > (int)mText.length())
		mCursor = (unsigned int)mText.length();
}

void TextEditComponent::onCursorChanged()
{
	if (isMultiline()) {
		Vector2f textSize = mFont->
				getWrappedTextCursorOffset(mText, getTextAreaSize().x(), mCursor);

		if (mScrollOffset.y() + getTextAreaSize().y() < textSize.y() +
				mFont->getHeight())  // Need to scroll down?
			mScrollOffset[1] = textSize.y() - getTextAreaSize().y() + mFont->getHeight();
		else if (mScrollOffset.y() > textSize.y())  // Need to scroll up?
			mScrollOffset[1] = textSize.y();
	}
	else {
		Vector2f cursorPos = mFont->sizeText(mText.substr(0, mCursor));

		if (mScrollOffset.x() + getTextAreaSize().x() < cursorPos.x())
			mScrollOffset[0] = cursorPos.x() - getTextAreaSize().x();
		else if (mScrollOffset.x() > cursorPos.x())
			mScrollOffset[0] = cursorPos.x();
	}
}

void TextEditComponent::render(const Transform4x4f& parentTrans)
{
	Transform4x4f trans = getTransform() * parentTrans;
	renderChildren(trans);

	// Text + cursor rendering.
	// Offset into our "text area" (padding).
	trans.translation() += Vector3f(getTextAreaPos().x(), getTextAreaPos().y(), 0);

	Vector2i clipPos((int)trans.translation().x(), (int)trans.translation().y());
	// Use "text area" size for clipping.
	Vector3f dimScaled = trans * Vector3f(getTextAreaSize().x(), getTextAreaSize().y(), 0);
	Vector2i clipDim((int)(dimScaled.x() - trans.translation().x()), (int)(dimScaled.y() -
			trans.translation().y()));
	Renderer::pushClipRect(clipPos, clipDim);

	trans.translate(Vector3f(-mScrollOffset.x(), -mScrollOffset.y(), 0));
	Renderer::setMatrix(trans);

	if (mTextCache)
		mFont->renderTextCache(mTextCache.get());

	// Pop the clip early to allow the cursor to be drawn outside of the "text area".
	Renderer::popClipRect();

	// Draw cursor.
	if (mEditing) {
		Vector2f cursorPos;
		if (isMultiline()) {
			cursorPos = mFont->getWrappedTextCursorOffset(mText, getTextAreaSize().x(), mCursor);
		}
		else {
			cursorPos = mFont->sizeText(mText.substr(0, mCursor));
			cursorPos[1] = 0;
		}

		float cursorHeight = mFont->getHeight() * 0.8f;
		Renderer::drawRect(cursorPos.x(), cursorPos.y() + (mFont->getHeight() -
				cursorHeight) / 2, 2.0f, cursorHeight, 0x000000FF, 0x000000FF);
	}
}

bool TextEditComponent::isMultiline()
{
	return (getSize().y() > mFont->getHeight() * 1.25f);
}

Vector2f TextEditComponent::getTextAreaPos() const
{
	return Vector2f(TEXT_PADDING_HORIZ / 2.0f, TEXT_PADDING_VERT / 2.0f);
}

Vector2f TextEditComponent::getTextAreaSize() const
{
	return Vector2f(mSize.x() - TEXT_PADDING_HORIZ, mSize.y() - TEXT_PADDING_VERT);
}

std::vector<HelpPrompt> TextEditComponent::getHelpPrompts()
{
	std::vector<HelpPrompt> prompts;
	if (mEditing) {
		prompts.push_back(HelpPrompt("up/down/left/right", "move cursor"));
		prompts.push_back(HelpPrompt("y", "backspace"));
		prompts.push_back(HelpPrompt("b", "stop editing"));
	}
	else {
		prompts.push_back(HelpPrompt("a", "edit"));
	}
	return prompts;
}