package net.minecraft.client.gui.font;

import java.util.function.Consumer;
import java.util.function.Predicate;
import java.util.function.Supplier;
import net.fabricmc.api.EnvType;
import net.fabricmc.api.Environment;
import net.minecraft.ChatFormatting;
import net.minecraft.client.Minecraft;
import net.minecraft.client.StringSplitter;
import net.minecraft.client.input.CharacterEvent;
import net.minecraft.client.input.KeyEvent;
import net.minecraft.util.Mth;
import net.minecraft.util.Util;

@Environment(EnvType.CLIENT)
public class TextFieldHelper {
	private final Supplier<String> getMessageFn;
	private final Consumer<String> setMessageFn;
	private final Supplier<String> getClipboardFn;
	private final Consumer<String> setClipboardFn;
	private final Predicate<String> stringValidator;
	private int cursorPos;
	private int selectionPos;

	public TextFieldHelper(
		final Supplier<String> getMessageFn,
		final Consumer<String> setMessageFn,
		final Supplier<String> getClipboardFn,
		final Consumer<String> setClipboardFn,
		final Predicate<String> stringValidator
	) {
		this.getMessageFn = getMessageFn;
		this.setMessageFn = setMessageFn;
		this.getClipboardFn = getClipboardFn;
		this.setClipboardFn = setClipboardFn;
		this.stringValidator = stringValidator;
		this.setCursorToEnd();
	}

	public static Supplier<String> createClipboardGetter(final Minecraft minecraft) {
		return () -> getClipboardContents(minecraft);
	}

	public static String getClipboardContents(final Minecraft minecraft) {
		return ChatFormatting.stripFormatting(minecraft.keyboardHandler.getClipboard().replaceAll("\\r", ""));
	}

	public static Consumer<String> createClipboardSetter(final Minecraft minecraft) {
		return text -> setClipboardContents(minecraft, text);
	}

	public static void setClipboardContents(final Minecraft minecraft, final String text) {
		minecraft.keyboardHandler.setClipboard(text);
	}

	public boolean charTyped(final CharacterEvent event) {
		if (event.isAllowedChatCharacter()) {
			this.insertText((String)this.getMessageFn.get(), event.codepointAsString());
		}

		return true;
	}

	public boolean keyPressed(final KeyEvent event) {
		if (event.isSelectAll()) {
			this.selectAll();
			return true;
		} else if (event.isCopy()) {
			this.copy();
			return true;
		} else if (event.isPaste()) {
			this.paste();
			return true;
		} else if (event.isCut()) {
			this.cut();
			return true;
		} else {
			TextFieldHelper.CursorStep cursorStep = event.hasControlDownWithQuirk() ? TextFieldHelper.CursorStep.WORD : TextFieldHelper.CursorStep.CHARACTER;
			if (event.key() == 259) {
				this.removeFromCursor(-1, cursorStep);
				return true;
			} else {
				if (event.key() == 261) {
					this.removeFromCursor(1, cursorStep);
				} else {
					if (event.isLeft()) {
						this.moveBy(-1, event.hasShiftDown(), cursorStep);
						return true;
					}

					if (event.isRight()) {
						this.moveBy(1, event.hasShiftDown(), cursorStep);
						return true;
					}

					if (event.key() == 268) {
						this.setCursorToStart(event.hasShiftDown());
						return true;
					}

					if (event.key() == 269) {
						this.setCursorToEnd(event.hasShiftDown());
						return true;
					}
				}

				return false;
			}
		}
	}

	private int clampToMsgLength(final int value) {
		return Mth.clamp(value, 0, ((String)this.getMessageFn.get()).length());
	}

	private void insertText(String message, final String text) {
		if (this.selectionPos != this.cursorPos) {
			message = this.deleteSelection(message);
		}

		this.cursorPos = Mth.clamp(this.cursorPos, 0, message.length());
		String newPageText = new StringBuilder(message).insert(this.cursorPos, text).toString();
		if (this.stringValidator.test(newPageText)) {
			this.setMessageFn.accept(newPageText);
			this.selectionPos = this.cursorPos = Math.min(newPageText.length(), this.cursorPos + text.length());
		}
	}

	public void insertText(final String text) {
		this.insertText((String)this.getMessageFn.get(), text);
	}

	private void resetSelectionIfNeeded(final boolean selecting) {
		if (!selecting) {
			this.selectionPos = this.cursorPos;
		}
	}

	public void moveBy(final int count, final boolean selecting, final TextFieldHelper.CursorStep scope) {
		switch (scope) {
			case CHARACTER:
				this.moveByChars(count, selecting);
				break;
			case WORD:
				this.moveByWords(count, selecting);
		}
	}

	public void moveByChars(final int count) {
		this.moveByChars(count, false);
	}

	public void moveByChars(final int count, final boolean selecting) {
		this.cursorPos = Util.offsetByCodepoints((String)this.getMessageFn.get(), this.cursorPos, count);
		this.resetSelectionIfNeeded(selecting);
	}

	public void moveByWords(final int count) {
		this.moveByWords(count, false);
	}

	public void moveByWords(final int count, final boolean selecting) {
		this.cursorPos = StringSplitter.getWordPosition((String)this.getMessageFn.get(), count, this.cursorPos, true);
		this.resetSelectionIfNeeded(selecting);
	}

	public void removeFromCursor(final int count, final TextFieldHelper.CursorStep scope) {
		switch (scope) {
			case CHARACTER:
				this.removeCharsFromCursor(count);
				break;
			case WORD:
				this.removeWordsFromCursor(count);
		}
	}

	public void removeWordsFromCursor(final int count) {
		int wordPosition = StringSplitter.getWordPosition((String)this.getMessageFn.get(), count, this.cursorPos, true);
		this.removeCharsFromCursor(wordPosition - this.cursorPos);
	}

	public void removeCharsFromCursor(final int count) {
		String message = (String)this.getMessageFn.get();
		if (!message.isEmpty()) {
			String newMessage;
			if (this.selectionPos != this.cursorPos) {
				newMessage = this.deleteSelection(message);
			} else {
				int otherPos = Util.offsetByCodepoints(message, this.cursorPos, count);
				int start = Math.min(otherPos, this.cursorPos);
				int end = Math.max(otherPos, this.cursorPos);
				newMessage = new StringBuilder(message).delete(start, end).toString();
				if (count < 0) {
					this.selectionPos = this.cursorPos = start;
				}
			}

			this.setMessageFn.accept(newMessage);
		}
	}

	public void cut() {
		String message = (String)this.getMessageFn.get();
		this.setClipboardFn.accept(this.getSelected(message));
		this.setMessageFn.accept(this.deleteSelection(message));
	}

	public void paste() {
		this.insertText((String)this.getMessageFn.get(), (String)this.getClipboardFn.get());
		this.selectionPos = this.cursorPos;
	}

	public void copy() {
		this.setClipboardFn.accept(this.getSelected((String)this.getMessageFn.get()));
	}

	public void selectAll() {
		this.selectionPos = 0;
		this.cursorPos = ((String)this.getMessageFn.get()).length();
	}

	private String getSelected(final String text) {
		int startIndex = Math.min(this.cursorPos, this.selectionPos);
		int endIndex = Math.max(this.cursorPos, this.selectionPos);
		return text.substring(startIndex, endIndex);
	}

	private String deleteSelection(final String message) {
		if (this.selectionPos == this.cursorPos) {
			return message;
		} else {
			int startIndex = Math.min(this.cursorPos, this.selectionPos);
			int endIndex = Math.max(this.cursorPos, this.selectionPos);
			String updatedText = message.substring(0, startIndex) + message.substring(endIndex);
			this.selectionPos = this.cursorPos = startIndex;
			return updatedText;
		}
	}

	public void setCursorToStart() {
		this.setCursorToStart(false);
	}

	public void setCursorToStart(final boolean selecting) {
		this.cursorPos = 0;
		this.resetSelectionIfNeeded(selecting);
	}

	public void setCursorToEnd() {
		this.setCursorToEnd(false);
	}

	public void setCursorToEnd(final boolean selecting) {
		this.cursorPos = ((String)this.getMessageFn.get()).length();
		this.resetSelectionIfNeeded(selecting);
	}

	public int getCursorPos() {
		return this.cursorPos;
	}

	public void setCursorPos(final int value) {
		this.setCursorPos(value, true);
	}

	public void setCursorPos(final int value, final boolean selecting) {
		this.cursorPos = this.clampToMsgLength(value);
		this.resetSelectionIfNeeded(selecting);
	}

	public int getSelectionPos() {
		return this.selectionPos;
	}

	public void setSelectionPos(final int value) {
		this.selectionPos = this.clampToMsgLength(value);
	}

	public void setSelectionRange(final int start, final int end) {
		int maxSize = ((String)this.getMessageFn.get()).length();
		this.cursorPos = Mth.clamp(start, 0, maxSize);
		this.selectionPos = Mth.clamp(end, 0, maxSize);
	}

	public boolean isSelecting() {
		return this.cursorPos != this.selectionPos;
	}

	@Environment(EnvType.CLIENT)
	public static enum CursorStep {
		CHARACTER,
		WORD;
	}
}