/*
 * opsu! - an open-source osu! client
 * Copyright (C) 2014 Jeffrey Han
 *
 * opsu! is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * opsu! is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with opsu!.  If not, see <http://www.gnu.org/licenses/>.
 */

package itdelatrisu.opsu;

import itdelatrisu.opsu.states.Options;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.FilenameFilter;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.LinkedList;

import org.newdawn.slick.Color;
import org.newdawn.slick.util.Log;

/**
 * Parser for OSU files.
 */
public class OsuParser {
	/**
	 * The x and y multipliers for hit object coordinates.
	 */
	private static float xMultiplier, yMultiplier;

	/**
	 * The x and y offsets for hit object coordinates.
	 */
	private static int
		xOffset,   // offset right of border
		yOffset;   // offset below health bar

	// This class should not be instantiated.
	private OsuParser() {}

	/**
	 * Invokes parser for each OSU file in a root directory.
	 * @param root the root directory (search has depth 1)
	 * @param width the container width
	 * @param height the container height
	 */
	public static void parseAllFiles(File root, int width, int height) {
		// set coordinate modifiers
		xMultiplier = (width * 0.6f) / OsuHitObject.MAX_X;
		yMultiplier = (height * 0.6f) / OsuHitObject.MAX_Y;
		xOffset = width / 5;
		yOffset = height / 5;

		for (File folder : root.listFiles()) {
			if (!folder.isDirectory())
				continue;
			File[] files = folder.listFiles(new FilenameFilter() {
				@Override
				public boolean accept(File dir, String name) {
					return name.toLowerCase().endsWith(".osu");
				}
			});
			if (files.length < 1)
				continue;

			// create a new group entry
			ArrayList<OsuFile> osuFiles = new ArrayList<OsuFile>();
			for (File file : files) {
				// Parse hit objects only when needed to save time/memory.
				// Change boolean to 'true' to parse them immediately.
				parseFile(file, osuFiles, false);
			}
			if (!osuFiles.isEmpty()) {  // add entry if non-empty
				Collections.sort(osuFiles);
				Opsu.groups.addSongGroup(osuFiles);
			}
		}
	}

	/**
	 * Parses an OSU file.
	 * @param file the file to parse
	 * @param osuFiles the song group
	 * @param parseObjects if true, hit objects will be fully parsed now
	 * @return the new OsuFile object
	 */
	private static OsuFile parseFile(File file, ArrayList<OsuFile> osuFiles, boolean parseObjects) {
		OsuFile osu = new OsuFile(file);
		String tags = ""; // parse at end, only if valid OsuFile

		try (BufferedReader in = new BufferedReader(new FileReader(file))) {

			// copy the default combo colors
			osu.combo = Arrays.copyOf(Options.DEFAULT_COMBO, Options.DEFAULT_COMBO.length);
			// initialize timing point list
			osu.timingPoints = new ArrayList<OsuTimingPoint>();

			String line = in.readLine();
			String tokens[];
			while (line != null) {
				line = line.trim();
				if (!isValidLine(line)) {
					line = in.readLine();
					continue;
				}
				switch (line) {
				case "[General]":
					while ((line = in.readLine()) != null) {
						line = line.trim();
						if (!isValidLine(line))
							continue;
						if (line.charAt(0) == '[')
							break;
						tokens = tokenize(line);
						switch (tokens[0]) {
						case "AudioFilename":
							osu.audioFilename = new File(file.getParent() + File.separator + tokens[1]);
							break;
						case "AudioLeadIn":
							osu.audioLeadIn = Integer.parseInt(tokens[1]);
							break;
//						case "AudioHash":  // deprecated
//							osu.audioHash = tokens[1];
//							break;
						case "PreviewTime":
							osu.previewTime = Integer.parseInt(tokens[1]);
							break;
						case "Countdown":
							osu.countdown = Byte.parseByte(tokens[1]);
							break;
						case "SampleSet":
							osu.sampleSet = tokens[1];
							break;
						case "StackLeniency":
							osu.stackLeniency = Float.parseFloat(tokens[1]);
							break;
						case "Mode":
							osu.mode = Byte.parseByte(tokens[1]);

							/* Non-Opsu! standard files not implemented (obviously). */
							if (osu.mode != 0)
								return null;

							break;
						case "LetterboxInBreaks":
							osu.letterboxInBreaks = (Integer.parseInt(tokens[1]) == 1);
							break;
						case "WidescreenStoryboard":
							osu.widescreenStoryboard = (Integer.parseInt(tokens[1]) == 1);
							break;
						case "EpilepsyWarning":
							osu.epilepsyWarning = (Integer.parseInt(tokens[1]) == 1);
						default:
							break;
						}
					}
					break;
				case "[Editor]":
					while ((line = in.readLine()) != null) {
						line = line.trim();
						if (!isValidLine(line))
							continue;
						if (line.charAt(0) == '[')
							break;
						/* Not implemented. */
//						tokens = tokenize(line);
//						switch (tokens[0]) {
//						case "Bookmarks":
//							String[] bookmarks = tokens[1].split(",");
//							osu.bookmarks = new int[bookmarks.length];
//							for (int i = 0; i < bookmarks.length; i++)
//								osu.bookmarks[i] = Integer.parseInt(bookmarks[i]);
//							break;
//						case "DistanceSpacing":
//							osu.distanceSpacing = Float.parseFloat(tokens[1]);
//							break;
//						case "BeatDivisor":
//							osu.beatDivisor = Byte.parseByte(tokens[1]);
//							break;
//						case "GridSize":
//							osu.gridSize = Integer.parseInt(tokens[1]);
//							break;
//						case "TimelineZoom":
//							osu.timelineZoom = Integer.parseInt(tokens[1]);
//							break;
//						default:
//							break;
//						}
					}
					break;
				case "[Metadata]":
					while ((line = in.readLine()) != null) {
						line = line.trim();
						if (!isValidLine(line))
							continue;
						if (line.charAt(0) == '[')
							break;
						tokens = tokenize(line);
						switch (tokens[0]) {
						case "Title":
							osu.title = tokens[1];
							break;
						case "TitleUnicode":
							osu.titleUnicode = tokens[1];
							break;
						case "Artist":
							osu.artist = tokens[1];
							break;
						case "ArtistUnicode":
							osu.artistUnicode = tokens[1];
							break;
						case "Creator":
							osu.creator = tokens[1];
							break;
						case "Version":
							osu.version = tokens[1];
							break;
						case "Source":
							osu.source = tokens[1];
							break;
						case "Tags":
							tags = tokens[1];
							break;
						case "BeatmapID":
							osu.beatmapID = Integer.parseInt(tokens[1]);
							break;
						case "BeatmapSetID":
							osu.beatmapSetID = Integer.parseInt(tokens[1]);
							break;
						}
					}
					break;
				case "[Difficulty]":
					while ((line = in.readLine()) != null) {
						line = line.trim();
						if (!isValidLine(line))
							continue;
						if (line.charAt(0) == '[')
							break;
						tokens = tokenize(line);
						switch (tokens[0]) {
						case "HPDrainRate":
							osu.HPDrainRate = Float.parseFloat(tokens[1]);
							break;
						case "CircleSize":
							osu.circleSize = Float.parseFloat(tokens[1]);
							break;
						case "OverallDifficulty":
							osu.overallDifficulty = Float.parseFloat(tokens[1]);
							break;
						case "ApproachRate":
							osu.approachRate = Float.parseFloat(tokens[1]);
							break;
						case "SliderMultiplier":
							osu.sliderMultiplier = Float.parseFloat(tokens[1]);
							break;
						case "SliderTickRate":
							osu.sliderTickRate = Float.parseFloat(tokens[1]);
							break;
						}
					}
					if (osu.approachRate == -1f)  // not in old format
						osu.approachRate = osu.overallDifficulty;
					break;
				case "[Events]":
					while ((line = in.readLine()) != null) {
						line = line.trim();
						if (!isValidLine(line))
							continue;
						if (line.charAt(0) == '[')
							break;
						tokens = line.split(",");
						switch (tokens[0]) {
						case "0":  // background
							tokens[2] = tokens[2].replaceAll("^\"|\"$", "");
							String ext = OsuParser.getExtension(tokens[2]);
							if (ext.equals("jpg") || ext.equals("png"))
								osu.bg = file.getParent() + File.separator + tokens[2];
							break;
						case "2":  // break periods
							if (osu.breaks == null)  // optional, create if needed
								osu.breaks = new ArrayList<Integer>();
							osu.breaks.add(Integer.parseInt(tokens[1]));
							osu.breaks.add(Integer.parseInt(tokens[2]));
							break;
						default:
							/* Not implemented. */
							break;
						}
					}
					break;
				case "[TimingPoints]":
					while ((line = in.readLine()) != null) {
						line = line.trim();
						if (!isValidLine(line))
							continue;
						if (line.charAt(0) == '[')
							break;
						tokens = line.split(",");

						OsuTimingPoint timingPoint = new OsuTimingPoint();
						try {  // newer file versions have many new fields
							timingPoint.time = (int) Float.parseFloat(tokens[0]);  //rare float
							timingPoint.meter = Integer.parseInt(tokens[2]);
							timingPoint.sampleType = Byte.parseByte(tokens[3]);
							timingPoint.sampleTypeCustom = Byte.parseByte(tokens[4]);
							timingPoint.sampleVolume = Integer.parseInt(tokens[5]);
							timingPoint.inherited = (Integer.parseInt(tokens[6]) == 1);
							timingPoint.kiai = (Integer.parseInt(tokens[7]) == 1);
						} catch (ArrayIndexOutOfBoundsException e) {
							// TODO: better support for old formats
//							Log.error(String.format("Error while parsing TimingPoints, line: '%s'.", line), e);
						}

						// tokens[1] is either beatLength (positive) or velocity (negative)
						float beatLength = Float.parseFloat(tokens[1]);
						if (beatLength > 0) {
							timingPoint.beatLength = beatLength;
							int bpm = Math.round(60000 / beatLength);
							if (osu.bpmMin == 0)
								osu.bpmMin = osu.bpmMax = bpm;
							else if (bpm < osu.bpmMin)
								osu.bpmMin = bpm;
							else if (bpm > osu.bpmMax)
								osu.bpmMax = bpm;
						} else
							timingPoint.velocity = (int) beatLength;

						osu.timingPoints.add(timingPoint);
					}
					break;
				case "[Colours]":
					LinkedList<Color> colors = new LinkedList<Color>();
					while ((line = in.readLine()) != null) {
						line = line.trim();
						if (!isValidLine(line))
							continue;
						if (line.charAt(0) == '[')
							break;
						tokens = tokenize(line);
						switch (tokens[0]) {
						case "Combo1":
						case "Combo2":
						case "Combo3":
						case "Combo4":
						case "Combo5":
						case "Combo6":
						case "Combo7":
						case "Combo8":
							String[] rgb = tokens[1].split(",");
							colors.add(new Color(
								Integer.parseInt(rgb[0]),
								Integer.parseInt(rgb[1]),
								Integer.parseInt(rgb[2])
							));
						default:
							break;
						}
					}
					if (!colors.isEmpty())
						osu.combo = colors.toArray(new Color[colors.size()]);
					break;
				case "[HitObjects]":
					while ((line = in.readLine()) != null) {
						line = line.trim();
						if (!isValidLine(line))
							continue;
						if (line.charAt(0) == '[')
							break;
						/* Only type counts parsed at this time. */
						tokens = line.split(",");
						int type = Integer.parseInt(tokens[3]);
						if ((type & OsuHitObject.TYPE_CIRCLE) > 0)
							osu.hitObjectCircle++;
						else if ((type & OsuHitObject.TYPE_SLIDER) > 0)
							osu.hitObjectSlider++;
						else //if ((type & OsuHitObject.TYPE_SPINNER) > 0)
							osu.hitObjectSpinner++;
					}
					break;
				default:
					line = in.readLine().trim();
					break;
				}
			}
		} catch (IOException e) {
			Log.error(String.format("Failed to read file '%s'.", file.getAbsolutePath()), e);
		}

		// if no custom colors, use the default color scheme
		if (osu.combo == null)
			osu.combo = Options.DEFAULT_COMBO;

		// add tags
		if (!tags.isEmpty()) {
			for (String tag : tags.split(" "))
				Opsu.groups.addTag(tag, osuFiles);
		}

		// parse hit objects now?
		if (parseObjects)
			parseHitObjects(osu);

		// add OsuFile to song group
		osuFiles.add(osu);
		return osu;
	}

	/**
	 * Parses all hit objects in an OSU file.
	 *
	 * Object formats:
	 * - Circles  [1]:
	 *   x,y,time,type,hitSound,addition
	 *   256,148,9466,1,2,0:0:0:0:
	 *
	 * - Sliders  [2]:
	 *   x,y,time,type,hitSound,sliderType|curveX:curveY|...,repeat,pixelLength,edgeHitsound,edgeAddition,addition
	 *   300,68,4591,2,0,B|372:100|332:172|420:192,2,180,2|2|2,0:0|0:0|0:0,0:0:0:0:
	 *
	 * - Spinners [8]:
	 *   x,y,time,type,hitSound,endTime,addition
	 *   256,192,654,12,0,4029,0:0:0:0:
	 *
	 * Notes:
	 * - 'addition' is optional, and defaults to "0:0:0:0:".
	 * - Field descriptions are located in OsuHitObject.java.
	 */
	public static void parseHitObjects(OsuFile osu) {
		if (osu.objects != null)  // already parsed
			return;

		osu.objects = new OsuHitObject[(osu.hitObjectCircle
				+ osu.hitObjectSlider + osu.hitObjectSpinner)];

		try (BufferedReader in = new BufferedReader(new FileReader(osu.getFile()))) {
			String line = in.readLine();
			while (line != null) {
				line = line.trim();
				if (!line.equals("[HitObjects]")) {
					line = in.readLine();
					continue;
				}

				int i = 0;            // object index
				int comboIndex = 0;   // color index
				int comboNumber = 1;  // combo number
				String tokens[], sliderTokens[], sliderXY[];

				while ((line = in.readLine()) != null && i < osu.objects.length) {
					line = line.trim();
					if (!isValidLine(line))
						continue;
					if (line.charAt(0) == '[')
						break;
					// create a new OsuHitObject for each line
					tokens = line.split(",");
					float scaledX = Integer.parseInt(tokens[0]) * xMultiplier + xOffset;
					float scaledY = Integer.parseInt(tokens[1]) * yMultiplier + yOffset;
					int type = Integer.parseInt(tokens[3]);
					osu.objects[i] = new OsuHitObject(
							scaledX, scaledY, Integer.parseInt(tokens[2]),
							type, Byte.parseByte(tokens[4])
					);
					if ((type & OsuHitObject.TYPE_CIRCLE) > 0) {
						/* 'addition' not implemented. */
					} else if ((type & OsuHitObject.TYPE_SLIDER) > 0) {
						// slider curve type and coordinates
						sliderTokens = tokens[5].split("\\|");
						osu.objects[i].sliderType = sliderTokens[0].charAt(0);
						osu.objects[i].sliderX = new float[sliderTokens.length-1];
						osu.objects[i].sliderY = new float[sliderTokens.length-1];
						for (int j = 1; j < sliderTokens.length; j++) {
							sliderXY = sliderTokens[j].split(":");
							osu.objects[i].sliderX[j-1] = Integer.parseInt(sliderXY[0]) * xMultiplier + xOffset;
							osu.objects[i].sliderY[j-1] = Integer.parseInt(sliderXY[1]) * yMultiplier + yOffset;
						}

						osu.objects[i].repeat = Integer.parseInt(tokens[6]);
						osu.objects[i].pixelLength = Float.parseFloat(tokens[7]);
						/* edge fields and 'addition' not implemented. */
					} else { //if ((type & OsuHitObject.TYPE_SPINNER) > 0) {
						// some 'endTime' fields contain a ':' character (?)
						int index = tokens[5].indexOf(':');
						if (index != -1)
							tokens[5] = tokens[5].substring(0, index);
						osu.objects[i].endTime = Integer.parseInt(tokens[5]);
						/* 'addition' not implemented. */
					}

					// set combo info
					// - new combo: get next combo index, reset combo number
					// - else:      maintain combo index, increase combo number
					if ((osu.objects[i].type & OsuHitObject.TYPE_NEWCOMBO) > 0) {
						comboIndex = (comboIndex + 1) % osu.combo.length;
						comboNumber = 1;
					}
					osu.objects[i].comboIndex = comboIndex;
					osu.objects[i].comboNumber = comboNumber++;

					i++;
				}
				break;
			}
		} catch (IOException e) {
			Log.error(String.format("Failed to read file '%s'.", osu.getFile().getAbsolutePath()), e);
		}
	}

	/**
	 * Returns false if the line is too short or commented.
	 */
	private static boolean isValidLine(String line) {
		return (line.length() > 1 && !line.startsWith("//"));
	}

	/**
	 * Splits line into two strings: tag, value.
	 */
	private static String[] tokenize(String line) {
		String[] tokens = new String[2];
		try {
			int index = line.indexOf(':');
			tokens[0] = line.substring(0, index).trim();
			tokens[1] = line.substring(index + 1).trim();
		} catch (java.lang.StringIndexOutOfBoundsException e) {
			Log.error(String.format("Failed to tokenize line: '%s'.", line), e);
		}
		return tokens;
	}

	/**
	 * Returns the file extension of a file.
	 */
	public static String getExtension(String file) {
		int i = file.lastIndexOf('.');
		return (i > -1) ? file.substring(i + 1).toLowerCase() : "";
	}
}