// Copyright 2005-2007 onetsoft.com
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package com.onetsoft.fastjsp;


import com.onetsoft.fastjsp.util.StringUtils;

import java.io.CharArrayWriter;
import java.io.UnsupportedEncodingException;
import java.nio.charset.Charset;
import java.util.BitSet;
import java.util.Iterator;
import java.util.Map;
import java.util.TreeMap;


/**
 * @author <a href="mailto:hgw@onetsoft.com">hgw</a>
 */
class LinkImpl implements Link, Lifecycle {

    /**
     * URL構(gòu)造原則：
     * 1.url第一個參數(shù)以'-'連接，其他均以查詢參數(shù)構(gòu)造。SEO 搜索規(guī)則下，'－'連字符不宜超過2個，因此只嘗試靜態(tài)化第一個參數(shù)。
     * 2.由于第一個參數(shù)針對 append() 的第一次調(diào)用，或 map 的 iterator 第一個 next() 值。Action 與頁面“定位”沒有直接關(guān)系，故均以查詢參數(shù)構(gòu)造。
     * ..a:因此在設(shè)置參數(shù)map時，須注意該參數(shù)應(yīng)對“頁面定位”有幫助，如：bbs的主題列表的"forumID"、用戶信息的"uuserID"
     * 3.第一個參數(shù)不得包含 '/' 字符，若包含則以動態(tài)參數(shù)構(gòu)造，此時意味者所有參數(shù)都是查詢方式構(gòu)造的。原因如下：
     * ..若參數(shù)字符name or value包含 '/' 或 '-，則該參數(shù)以動態(tài)url方式構(gòu)造，原因：
     * ..a:'/':tomcat 6.x 會報錯："HTTP 400 - 錯誤請求"
     * ..b:'-'或其他參數(shù)分隔連接。避免構(gòu)造的性能損失
     * ..另：若第一個參數(shù)值是null，則該參數(shù)也會以“查詢參數(shù)”方式構(gòu)造。因為此時在靜態(tài)化參數(shù)已經(jīng)無意義。
     * 4.確實需要靜態(tài)參數(shù)連接的，可直接調(diào)用 append(XXX,YYY,staic)
     * 5.map參數(shù)全部強制構(gòu)造為查詢參數(shù)
     * 6.其他參見{@link Link}說明
     */

    /* encode 靜態(tài)變量 begin */
    static BitSet dontNeedEncoding;
    static final int caseDiff = ('a' - 'A');

    static {
        dontNeedEncoding = new BitSet(256);
        int i;
        for (i = 'a'; i <= 'z'; i++) {
            dontNeedEncoding.set(i);
        }
        for (i = 'A'; i <= 'Z'; i++) {
            dontNeedEncoding.set(i);
        }
        for (i = '0'; i <= '9'; i++) {
            dontNeedEncoding.set(i);
        }
        dontNeedEncoding.set(' '); /* encoding a space to a + is done
				    * in the encode() method */
        dontNeedEncoding.set('-');
        dontNeedEncoding.set('_');
        dontNeedEncoding.set('.');
        dontNeedEncoding.set('*');
    }
    /* encode 靜態(tài)變量 end */


    final static String UCI = "uci";//unique component id
    final static char sp = '-';
    final static char sl = '/';         //靜態(tài)參數(shù)若包含此字符，tomcat 6.x下會出現(xiàn)錯誤："HTTP 400 - 錯誤請求"
    final static String spx = "%2d";   // 參數(shù)值中'-'的url形式
    final static String qa = "&amp;"; //查詢參數(shù)將，是否需要設(shè)置為"&amp;" 呢 ?


    private AbstractComponent co = null;
    private String pageName = null;

    private boolean append = false;  //是否'-'方式構(gòu)造了靜態(tài)化參數(shù)
    StringBuffer buf = new StringBuffer();

    private boolean staticParamAppend = false; //第一次靜態(tài)url參數(shù)是否已經(jīng)構(gòu)造。注：第一次構(gòu)造調(diào)用即為true(無論構(gòu)造成功與否)，其他參數(shù)的"頁面定位"意義不明確。

    private String anchor = null;
    private Map params = null;
    private int len = -1;     //保存靜態(tài)參數(shù)url base 的長的，便于 Link 對象化操作（如：clone(),getURL(),toString()）后也能append()

    private StringBuffer qbuf = new StringBuffer(0);   //保存動態(tài)查詢參數(shù) e.g: a=XXX&b=YYY
    private int qBufLen = -1;    //保存動態(tài)查詢參數(shù)url base 的長的，便于 Link 對象化操作（如：clone(),getURL(),toString()）后也能append()

    private CharArrayWriter charArrayWriter = new CharArrayWriter();


    public LinkImpl() {
    }

    public LinkImpl setComponent(AbstractComponent co) {
        this.co = co;
        return this;
    }

    public LinkImpl setPageName(String pageName) {
        this.pageName = pageName;
        return this;
    }

    public void init() {
        co.service.servicer.stateURL.encodeBeforeUrlBuild(this);
    }

    public void recycle() {
        co = null;
        pageName = null;
        append = false;
        staticParamAppend = false;
        anchor = null;
        if (params != null)
            params.clear();
        len = -1;
        charArrayWriter.reset();
        buf.delete(0, buf.length());
        qbuf.delete(0, qbuf.length());
        qBufLen = -1;
    }

    public Object clone() {
        LinkImpl o = new LinkImpl();
        o.co = co;
        o.pageName = pageName;
        o.append = append;

        o.buf = new StringBuffer(buf.toString());
        o.qbuf = new StringBuffer(qbuf.toString());

        o.staticParamAppend = staticParamAppend;
        o.anchor = anchor;
        if (params != null)
            o.params = new TreeMap(params);
        o.len = len;

        return o;
    }

    private void ensuedAppend() {
        if (append) {
            buf.append(sp);
        } else {
            buf.append(pageName).append('/');
            append = true;
        }
    }

    private void ensureBuffers() {
        if (len != -1) {
            buf.delete(len, buf.length());
            len = -1;
        }
        if (qBufLen != -1) {
            qbuf.delete(qBufLen, qbuf.length());
            qBufLen = -1;
        }
    }

    private Link appends(String param, String value, int paramPerfered) {
        ensureBuffers();
        if (value == null || value.length() == 0) {
            encodeURLParamQueryString(param, value);
            return this;
        }
        if (!(paramPerfered==Link.STATIC && encodeURLParamStatic(param, value))) {
            encodeURLParamQueryString(param, value);
        }
        return this;
    }

    private Link appendq(String param, String value, boolean forceQueryString, boolean resetBufer) {
        if (resetBufer)
            ensureBuffers();
        boolean b = true;
        if (!forceQueryString) {
            if (!staticParamAppend) {
                staticParamAppend = true;
                if (value != null && value.length() > 0) {
                    b = !encodeURLParamStatic(param, value);//靜態(tài)參數(shù)添加失敗則以動態(tài)參數(shù)添加
                }
            }
        }
        if (b) {
            encodeURLParamQueryString(param, value);
        }

        return this;
    }

    /* 編碼靜態(tài)URL */
    private boolean encodeURLParamStatic(String param, String value) {
        if (value.indexOf(sl) != -1) return false;

        ensuedAppend();
        buf.append(param).append(sp);
        encodeURLParam(buf, value, co.service.servicer.module.charset, true);

        return true;
    }

    /* 編碼查詢參數(shù) */
    private void encodeURLParamQueryString(String param, String value) {
        /*存在特殊字符 */
        if (qbuf.length() > 0) {
            qbuf.append(qa);
        }

        qbuf.append(param).append('=');

        if (value == null || value.length() == 0) {
            qbuf.append(StringUtils.EMPTY);
        } else {
            encodeURLParam(qbuf, value, co.service.servicer.module.charset, false);
        }

        /* try {
        if (value != null)
            value = URLEncoder.encode(value, co.service.servicer.module.encoding);
    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    }
    if (value != null)
        qbuf.append(value);
    else
        qbuf.append(StringUtils.EMPTY);*/

    }


    public Link append(String param, String value) {
        ensureBuffers();
        return appendq(param, value, false, true);
    }

    public Link append(String param, String value, int paramPerfered) {
        return appends(param, value, paramPerfered);
    }

    public Link append(String param, long value) {