// HTML 支持的数学符号
function strNumDiscode(str){
    str = str.replace(/∀/g, '∀');
    str = str.replace(/∂/g, '∂');
    str = str.replace(/&exists;/g, '∃');
    str = str.replace(/∅/g, '∅');
    str = str.replace(/∇/g, '∇');
    str = str.replace(/∈/g, '∈');
    str = str.replace(/∉/g, '∉');
    str = str.replace(/∋/g, '∋');
    str = str.replace(/∏/g, '∏');
    str = str.replace(/∑/g, '∑');
    str = str.replace(/−/g, '−');
    str = str.replace(/∗/g, '∗');
    str = str.replace(/√/g, '√');
    str = str.replace(/∝/g, '∝');
    str = str.replace(/∞/g, '∞');
    str = str.replace(/∠/g, '∠');
    str = str.replace(/∧/g, '∧');
    str = str.replace(/∨/g, '∨');
    str = str.replace(/∩/g, '∩');
    str = str.replace(/∩/g, '∪');
    str = str.replace(/∫/g, '∫');
    str = str.replace(/∴/g, '∴');
    str = str.replace(/∼/g, '∼');
    str = str.replace(/≅/g, '≅');
    str = str.replace(/≈/g, '≈');
    str = str.replace(/≠/g, '≠');
    str = str.replace(/≤/g, '≤');
    str = str.replace(/≥/g, '≥');
    str = str.replace(/⊂/g, '⊂');
    str = str.replace(/⊃/g, '⊃');
    str = str.replace(/⊄/g, '⊄');
    str = str.replace(/⊆/g, '⊆');
    str = str.replace(/⊇/g, '⊇');
    str = str.replace(/⊕/g, '⊕');
    str = str.replace(/⊗/g, '⊗');
    str = str.replace(/⊥/g, '⊥');
    str = str.replace(/⋅/g, '⋅');
    return str;
}

//HTML 支持的希腊字母
function strGreeceDiscode(str){
    str = str.replace(/Α/g, 'Α');
    str = str.replace(/Β/g, 'Β');
    str = str.replace(/Γ/g, 'Γ');
    str = str.replace(/Δ/g, 'Δ');
    str = str.replace(/Ε/g, 'Ε');
    str = str.replace(/Ζ/g, 'Ζ');
    str = str.replace(/Η/g, 'Η');
    str = str.replace(/Θ/g, 'Θ');
    str = str.replace(/Ι/g, 'Ι');
    str = str.replace(/Κ/g, 'Κ');
    str = str.replace(/Λ/g, 'Λ');
    str = str.replace(/Μ/g, 'Μ');
    str = str.replace(/Ν/g, 'Ν');
    str = str.replace(/Ξ/g, 'Ν');
    str = str.replace(/Ο/g, 'Ο');
    str = str.replace(/Π/g, 'Π');
    str = str.replace(/Ρ/g, 'Ρ');
    str = str.replace(/Σ/g, 'Σ');
    str = str.replace(/Τ/g, 'Τ');
    str = str.replace(/Υ/g, 'Υ');
    str = str.replace(/Φ/g, 'Φ');
    str = str.replace(/Χ/g, 'Χ');
    str = str.replace(/Ψ/g, 'Ψ');
    str = str.replace(/Ω/g, 'Ω');

    str = str.replace(/α/g, 'α');
    str = str.replace(/β/g, 'β');
    str = str.replace(/γ/g, 'γ');
    str = str.replace(/δ/g, 'δ');
    str = str.replace(/ε/g, 'ε');
    str = str.replace(/ζ/g, 'ζ');
    str = str.replace(/η/g, 'η');
    str = str.replace(/θ/g, 'θ');
    str = str.replace(/ι/g, 'ι');
    str = str.replace(/κ/g, 'κ');
    str = str.replace(/λ/g, 'λ');
    str = str.replace(/μ/g, 'μ');
    str = str.replace(/ν/g, 'ν');
    str = str.replace(/ξ/g, 'ξ');
    str = str.replace(/ο/g, 'ο');
    str = str.replace(/π/g, 'π');
    str = str.replace(/ρ/g, 'ρ');
    str = str.replace(/ς/g, 'ς');
    str = str.replace(/σ/g, 'σ');
    str = str.replace(/τ/g, 'τ');
    str = str.replace(/υ/g, 'υ');
    str = str.replace(/φ/g, 'φ');
    str = str.replace(/χ/g, 'χ');
    str = str.replace(/ψ/g, 'ψ');
    str = str.replace(/ω/g, 'ω');
    str = str.replace(/ϑ/g, 'ϑ');
    str = str.replace(/ϒ/g, 'ϒ');
    str = str.replace(/ϖ/g, 'ϖ');
    str = str.replace(/·/g, '·');
    return str;
}

// 

function strcharacterDiscode(str){
    // 加入常用解析
    str = str.replace(/ /g, ' ');
    str = str.replace(/"/g, "'");
    str = str.replace(/&/g, '&');
    // str = str.replace(/</g, '‹');
    // str = str.replace(/>/g, '›');

    str = str.replace(/&lt;/g, '<');
    str = str.replace(/&gt;/g, '>');

    return str;
}

// HTML 支持的其他实体
function strOtherDiscode(str){
    str = str.replace(/&OElig;/g, 'Œ');
    str = str.replace(/&oelig;/g, 'œ');
    str = str.replace(/&Scaron;/g, 'Š');
    str = str.replace(/&scaron;/g, 'š');
    str = str.replace(/&Yuml;/g, 'Ÿ');
    str = str.replace(/&fnof;/g, 'ƒ');
    str = str.replace(/&circ;/g, 'ˆ');
    str = str.replace(/&tilde;/g, '˜');
    str = str.replace(/&ensp;/g, '');
    str = str.replace(/&emsp;/g, '');
    str = str.replace(/&thinsp;/g, '');
    str = str.replace(/&zwnj;/g, '');
    str = str.replace(/&zwj;/g, '');
    str = str.replace(/&lrm;/g, '');
    str = str.replace(/&rlm;/g, '');
    str = str.replace(/&ndash;/g, '–');
    str = str.replace(/&mdash;/g, '—');
    str = str.replace(/&lsquo;/g, '‘');
    str = str.replace(/&rsquo;/g, '’');
    str = str.replace(/&sbquo;/g, '‚');
    str = str.replace(/&ldquo;/g, '“');
    str = str.replace(/&rdquo;/g, '”');
    str = str.replace(/&bdquo;/g, '„');
    str = str.replace(/&dagger;/g, '†');
    str = str.replace(/&Dagger;/g, '‡');
    str = str.replace(/&bull;/g, '•');
    str = str.replace(/&hellip;/g, '…');
    str = str.replace(/&permil;/g, '‰');
    str = str.replace(/&prime;/g, '′');
    str = str.replace(/&Prime;/g, '″');
    str = str.replace(/&lsaquo;/g, '‹');
    str = str.replace(/&rsaquo;/g, '›');
    str = str.replace(/&oline;/g, '‾');
    str = str.replace(/&euro;/g, '€');
    str = str.replace(/&trade;/g, '™');

    str = str.replace(/&larr;/g, '←');
    str = str.replace(/&uarr;/g, '↑');
    str = str.replace(/&rarr;/g, '→');
    str = str.replace(/&darr;/g, '↓');
    str = str.replace(/&harr;/g, '↔');
    str = str.replace(/&crarr;/g, '↵');
    str = str.replace(/&lceil;/g, '⌈');
    str = str.replace(/&rceil;/g, '⌉');

    str = str.replace(/&lfloor;/g, '⌊');
    str = str.replace(/&rfloor;/g, '⌋');
    str = str.replace(/&loz;/g, '◊');
    str = str.replace(/&spades;/g, '♠');
    str = str.replace(/&clubs;/g, '♣');
    str = str.replace(/&hearts;/g, '♥');

    str = str.replace(/&diams;/g, '♦');

    return str;
}

function strMoreDiscode(str){
    str = str.replace(/\r\n/g,"");  
    str = str.replace(/\n/g,"");

    str = str.replace(/code/g,"wxxxcode-style");
    return str;
}

function strDiscode(str){
    str = strNumDiscode(str);
    str = strGreeceDiscode(str);
    str = strcharacterDiscode(str);
    str = strOtherDiscode(str);
    str = strMoreDiscode(str);
    return str;
}
function urlToHttpUrl(url,rep){
    
    var patt1 = new RegExp("^//");
    var result = patt1.test(url);
    if(result){
        url = rep+":"+url;
    }
    return  url;
}

module.exports = {
    strDiscode:strDiscode,
    urlToHttpUrl:urlToHttpUrl
}