package com.ismyway.anyview;

import javax.microedition.lcdui.Image;
import javax.microedition.lcdui.Graphics;
import java.io.*;

/**
 * <p>Title: AnyView</p>
 *
 * <p>Description: E680(I) Reader</p>
 *
 * <p>Copyright: Copyright (c) 2005</p>
 *
 * <p>Company: www.ismyway.com</p>
 *
 * @author ZhangJian
 * @version 1.0
 */
public class IAVReader {
    private String filename;

    public final static byte[] Sign = {(byte) 0x80, 'I', 'A', 'V'};
    public final static String IAVVersion = "1.0a";
    public final static int ANCHOR = Graphics.LEFT | Graphics.TOP;

    private byte[] Version;
    private byte[] Name;
    private byte[] Author;
    private byte[] Maker;
    private int CoverLen = 0;
    private Image Cover = null;
    private int ChapterNum = 0;
    private byte[][] ChaptersNames;

    private int currentChap = -1;
    private int iavLen = 0; //文檔總長度
    private int[] chapOffset; //每章節在文檔中的偏移，ChaptersNames=0時置空
    private byte[] chapType; //每章節的數據類型，ChaptersNames=0時置空，并且接下來的數據為TXT文本

    private byte[] temp;
    private FileSystemReader fsa;
    private boolean validDoc = true;

    public IAVReader(String filename) {
        this.filename = filename;
        fsa = new FileSystemReader(this.filename);
        iavLen = (int) fsa.fileSize();

        analysisIav();
    }

    private void analysisIav() {
        byte[] b = new byte[164];

        b = fsa.read(164);

        byte[] sign = getData(b, 0, 4);
        for (int i = 0; i < Sign.length && validDoc; i++) {
            if (sign[i] != Sign[i]) {
                validDoc = false;
            }
        }
        if (!validDoc) {
            Cover = AnyView.cf.buildImage("非法的IAV文件！");
            return;
        }
        Version = deleteZeroData(getData(b, 4, 6));
        String str = new String(Version);
        if (IAVVersion.compareTo(str) < 0) {
            validDoc = false;
            Cover = AnyView.cf.buildImage("無法打開 " + str + " 版本的文件！");
            return;
        }
        Name = deleteZeroData(getData(b, 10, 50));
        Author = deleteZeroData(getData(b, 60, 50));
        Maker = deleteZeroData(getData(b, 110, 50));
        CoverLen = getData(b, 160);
        b = null;
        if (CoverLen > 0) {
            byte[] cover = getData(CoverLen);
            Cover = Image.createImage(cover, 0, CoverLen);
        }
        ChapterNum = getInt();
        if (ChapterNum > 0) { //定義章節
            ChaptersNames = new byte[ChapterNum][];
            chapOffset = new int[ChapterNum];
            chapType = new byte[ChapterNum];
            byte[] temp = getData(ChapterNum * 64);

            int off = 0;
            for (int i = 0; i < ChapterNum; i++) {
                ChaptersNames[i] = getData(temp, off, 60);
                chapType[i] = ChaptersNames[i][59];
                ChaptersNames[i] = deleteZeroData(ChaptersNames[i]);
                off += 60;
                chapOffset[i] = getData(temp, off);
                off += 4;
            }
            temp = null;
        } else {
            validDoc = false;
            Cover = AnyView.cf.buildImage("章節不可為空！");
            return;
        }
    }


    public boolean isValidDoc() {
        return validDoc;
    }

    private byte[] deleteZeroData(byte[] b) {
        int counter = 0;
        while (true) {
            if (b[counter] == 0) {
                break;
            }
            counter++;
        }
        byte[] data = new byte[counter];
        System.arraycopy(b, 0, data, 0, counter);
        return data;
    }

    public Image getCover() {
        if (Cover != null) {
            return Cover;
        } else {
            Image img = Image.createImage(240, 320);
            Graphics g = img.getGraphics();
            g.setColor(0);
            g.fillRect(0, 0, 240, 320);
            AnyView.cf.setColor(0xFFFFFF);
            Image temp = AnyView.cf.buildImage(Name);
            int x = (240 - temp.getWidth()) >> 1;
            g.drawImage(temp, x, 50, ANCHOR);
            temp = null;

            temp = AnyView.cf.buildImage(Author);
            x = (240 - temp.getWidth()) >> 1;
            g.drawImage(temp, x, 80, ANCHOR);
            temp = null;

            temp = AnyView.cf.buildImage(Maker);
            x = (240 - temp.getWidth()) >> 1;
            g.drawImage(temp, x, 110, ANCHOR);
            temp = null;

            return img;
        }
    }

    public void close() {
        if (fsa != null) {
            fsa.close();
            fsa = null;
        }
    }

    public byte[] getChapter(int index) {
        if (!validDoc || index < 0 || index > ChapterNum - 1) {
            return null;
        }
        int off = chapOffset[index] - fsa.offset;
        int len = 0;
        if (index == ChapterNum - 1) {
            len = (int) iavLen - chapOffset[ChapterNum - 1];
        } else {
            len = chapOffset[index + 1] - chapOffset[index];
        }
        byte[] b = new byte[len];
        fsa.skip(off);
        b = fsa.read(len);
        currentChap = index;
        return b;
    }

    public byte[] getNextChapter() {
        if (!validDoc) {
            return null;
        }

        currentChap++;
        currentChap = currentChap > ChapterNum - 1 ? ChapterNum - 1 :
                      currentChap;
        int off = chapOffset[currentChap] - fsa.offset;
        int len = 0;
        if (currentChap == ChapterNum - 1) {
            len = (int) iavLen - chapOffset[ChapterNum - 1];
        } else {
            len = chapOffset[currentChap + 1] - chapOffset[currentChap];
        }
        byte[] b = new byte[len];
        fsa.skip(off);
        b = fsa.read(len);
        return b;
    }

    public byte[] getPreChapter() {
        if (!validDoc) {
            return null;
        }

        currentChap--;
        currentChap = currentChap < 0 ? 0 : currentChap;
        int off = chapOffset[currentChap] - fsa.offset;
        int len = chapOffset[currentChap + 1] - chapOffset[currentChap];
        byte[] b = new byte[len];
        fsa.skip(off);
        b = fsa.read(len);
        return b;
    }

    public int getCurentChapterIndex() {
        return currentChap;
    }

    /**
     * 返回當前的章節名列表
     * @return byte[][]
     */
    public String[] getChapterNames() {
        String[] list = null;
        if (ChapterNum < 1) {
            list = new String[] {"（無章節）"};
        } else {
            list = new String[ChapterNum];
            for (int i = 0; i < ChapterNum; i++) {
                try {
                    list[i] = "" + i + ". " +
                              new String(ChaptersNames[i], "UTF-8");
                } catch (UnsupportedEncodingException ex) {
                    list[i] = "" + i;
                }
            }
        }
        return list;
    }

    private byte[] getData(byte[] src, int offset, int len) {
        temp = new byte[len];
        System.arraycopy(src, offset, temp, 0, len);
        return temp;
    }

    private int getData(byte[] src, int offset) {
        byte[] b = new byte[4];
        System.arraycopy(src, offset, b, 0, 4);
        int v = (b[0] & 0xff) << 24 | (b[1] & 0xff) << 16 | (b[2] & 0xff) << 8 |
                (b[3] & 0xff);
        return v;
    }

    private byte[] getData(int len) {
        temp = new byte[len];
        temp = fsa.read(len);
        return temp;
    }

    private int getInt() {
        byte[] b = getData(4);
        int v = (b[0] & 0xff) << 24 | (b[1] & 0xff) << 16 | (b[2] & 0xff) << 8 |
                (b[3] & 0xff);
        return v;
    }
}