package com.mojang.blaze3d.preprocessor;

import com.google.common.base.Strings;
import com.google.common.collect.Lists;
import java.util.List;
import java.util.Locale;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import net.fabricmc.api.EnvType;
import net.fabricmc.api.Environment;
import net.minecraft.FileUtil;
import net.minecraft.client.renderer.ShaderDefines;
import net.minecraft.util.StringUtil;
import org.jetbrains.annotations.Nullable;

@Environment(EnvType.CLIENT)
public abstract class GlslPreprocessor {
	private static final String C_COMMENT = "/\\*(?:[^*]|\\*+[^*/])*\\*+/";
	private static final String LINE_COMMENT = "//[^\\v]*";
	private static final Pattern REGEX_MOJ_IMPORT = Pattern.compile(
		"(#(?:/\\*(?:[^*]|\\*+[^*/])*\\*+/|\\h)*moj_import(?:/\\*(?:[^*]|\\*+[^*/])*\\*+/|\\h)*(?:\"(.*)\"|<(.*)>))"
	);
	private static final Pattern REGEX_VERSION = Pattern.compile("(#(?:/\\*(?:[^*]|\\*+[^*/])*\\*+/|\\h)*version(?:/\\*(?:[^*]|\\*+[^*/])*\\*+/|\\h)*(\\d+))\\b");
	private static final Pattern REGEX_ENDS_WITH_WHITESPACE = Pattern.compile("(?:^|\\v)(?:\\s|/\\*(?:[^*]|\\*+[^*/])*\\*+/|(//[^\\v]*))*\\z");

	public List<String> process(String shaderData) {
		GlslPreprocessor.Context context = new GlslPreprocessor.Context();
		List<String> list = this.processImports(shaderData, context, "");
		list.set(0, this.setVersion((String)list.get(0), context.glslVersion));
		return list;
	}

	private List<String> processImports(String shaderData, GlslPreprocessor.Context context, String includeDirectory) {
		int i = context.sourceId;
		int j = 0;
		String string = "";
		List<String> list = Lists.<String>newArrayList();
		Matcher matcher = REGEX_MOJ_IMPORT.matcher(shaderData);

		while (matcher.find()) {
			if (!isDirectiveDisabled(shaderData, matcher, j)) {
				String string2 = matcher.group(2);
				boolean bl = string2 != null;
				if (!bl) {
					string2 = matcher.group(3);
				}

				if (string2 != null) {
					String string3 = shaderData.substring(j, matcher.start(1));
					String string4 = includeDirectory + string2;
					String string5 = this.applyImport(bl, string4);
					if (!Strings.isNullOrEmpty(string5)) {
						if (!StringUtil.endsWithNewLine(string5)) {
							string5 = string5 + System.lineSeparator();
						}

						context.sourceId++;
						int k = context.sourceId;
						List<String> list2 = this.processImports(string5, context, bl ? FileUtil.getFullResourcePath(string4) : "");
						list2.set(0, String.format(Locale.ROOT, "#line %d %d\n%s", 0, k, this.processVersions((String)list2.get(0), context)));
						if (!StringUtil.isBlank(string3)) {
							list.add(string3);
						}

						list.addAll(list2);
					} else {
						String string6 = bl ? String.format(Locale.ROOT, "/*#moj_import \"%s\"*/", string2) : String.format(Locale.ROOT, "/*#moj_import <%s>*/", string2);
						list.add(string + string3 + string6);
					}

					int k = StringUtil.lineCount(shaderData.substring(0, matcher.end(1)));
					string = String.format(Locale.ROOT, "#line %d %d", k, i);
					j = matcher.end(1);
				}
			}
		}

		String string2x = shaderData.substring(j);
		if (!StringUtil.isBlank(string2x)) {
			list.add(string + string2x);
		}

		return list;
	}

	private String processVersions(String versionData, GlslPreprocessor.Context context) {
		Matcher matcher = REGEX_VERSION.matcher(versionData);
		if (matcher.find() && isDirectiveEnabled(versionData, matcher)) {
			context.glslVersion = Math.max(context.glslVersion, Integer.parseInt(matcher.group(2)));
			return versionData.substring(0, matcher.start(1))
				+ "/*"
				+ versionData.substring(matcher.start(1), matcher.end(1))
				+ "*/"
				+ versionData.substring(matcher.end(1));
		} else {
			return versionData;
		}
	}

	private String setVersion(String versionData, int glslVersion) {
		Matcher matcher = REGEX_VERSION.matcher(versionData);
		return matcher.find() && isDirectiveEnabled(versionData, matcher)
			? versionData.substring(0, matcher.start(2)) + Math.max(glslVersion, Integer.parseInt(matcher.group(2))) + versionData.substring(matcher.end(2))
			: versionData;
	}

	private static boolean isDirectiveEnabled(String shaderData, Matcher matcher) {
		return !isDirectiveDisabled(shaderData, matcher, 0);
	}

	private static boolean isDirectiveDisabled(String shaderData, Matcher matcher, int offset) {
		int i = matcher.start() - offset;
		if (i == 0) {
			return false;
		} else {
			Matcher matcher2 = REGEX_ENDS_WITH_WHITESPACE.matcher(shaderData.substring(offset, matcher.start()));
			if (!matcher2.find()) {
				return true;
			} else {
				int j = matcher2.end(1);
				return j == matcher.start();
			}
		}
	}

	@Nullable
	public abstract String applyImport(boolean useFullPath, String directory);

	public static String injectDefines(String shaderSource, ShaderDefines defines) {
		if (defines.isEmpty()) {
			return shaderSource;
		} else {
			int i = shaderSource.indexOf(10);
			int j = i + 1;
			return shaderSource.substring(0, j) + defines.asSourceDirectives() + "#line 1 0\n" + shaderSource.substring(j);
		}
	}

	@Environment(EnvType.CLIENT)
	static final class Context {
		int glslVersion;
		int sourceId;
	}
}