package org.simantics.scl.compiler.markdown.internal;

import org.simantics.scl.compiler.markdown.inlines.Subject;

import gnu.trove.set.hash.THashSet;

public class Scanner {

    public int level;
    public int matched;
    public char bulletChar;
    
    public static boolean isCloseCodeFence(StringBuilder line, int offset, char fenceChar, int fenceLength) {
        int matched = 0;
        while(line.charAt(offset) == fenceChar) {
            ++offset;
            ++matched;
        }
        if(matched < fenceLength)
            return false;
        while(true) {
            char c = line.charAt(offset++);
            if(c == '\n')
                return true;
            else if(c != ' ')
                return false;
        }
    }
    
    public static boolean isSetextHeaderLine(StringBuilder line, int offset, char headerLineChar) {
        char c;
        while((c = line.charAt(offset)) == headerLineChar)
            ++offset;
        while(c == ' ') {
            ++offset;
            c = line.charAt(offset);
        }
        return c == '\n';
    }

    public static boolean isHRule(StringBuilder line, int offset, char hrChar) {
        char c;
        int count = 0;
        while((c = line.charAt(offset)) != '\n') {
            if(c == hrChar)
                ++count;
            else if(c != ' ')
                return false;
            ++offset;
        }
        return count >= 3;
    }

    public static boolean isHtmlBlockTag(StringBuilder line, int offset) {
        if(line.charAt(offset) != '<')
            return false;
        ++offset;
        char c = line.charAt(offset);
        
        // HTML comment, processing instruction, CDATA or entity definition
        if(c == '!' || c == '?')
            return true;

        // Ending tag
        if(c == '/') {
            ++offset;
            offset = scanTag(line, offset);
            if(offset == -1)
                return false;
            c = line.charAt(offset);
            return c == ' ' || c == '>';
        }
        
        // Beginning tag
        offset = scanTag(line, offset);
        if(offset == -1)
            return false;
        c = line.charAt(offset);
        return c == ' ' || c == '/' || c == '>';
    }
    
    public static int scanTag(StringBuilder line, int offset) {
        StringBuilder b = new StringBuilder();
        while(offset < line.length()) {
            char c = line.charAt(offset);
            if( (c >= 'a' && c <= 'z') || (c >= '0' && c <= '9') )
                b.append(c);
            else if( c >= 'A' && c <= 'Z' )
                b.append(Character.toLowerCase(c));
            else
                break;
            ++offset;
        }
        if(HTML_BLOCK_TAG_SET.contains(b.toString()))
            return offset;
        else
            return -1;
    }
    
    private static final String[] HTML_BLOCK_TAGS = new String[] {
        "article", "header", "aside", "hgroup", "blockquote", "hr", "iframe", "body", "li", "map", "button", "object", "canvas", "ol",
        "caption", "output", "col", "p", "colgroup", "pre", "dd", "progress", "div", "section", "dl", "table", "td", "dt", "tbody",
        "embed", "textarea", "fieldset", "tfoot", "figcaption", "th", "figure", "thead", "footer", "tr", "form", "ul", "h1", "h2", "h3",
        "h4", "h5", "h6", "video", "script", "style"
    };
    private static final THashSet<String> HTML_BLOCK_TAG_SET = new THashSet<String>();
    static {
        for(String tag : HTML_BLOCK_TAGS)
            HTML_BLOCK_TAG_SET.add(tag);
    }
    
    public boolean isAtxHeaderStart(StringBuilder line, int offset) {
        int matched = 0;
        char c;
        while((c = line.charAt(offset)) == '#') {
            ++offset;
            ++matched;
        }
        if(matched == 0 || matched > 6)
            return false;
        this.level = matched;
        if(c != '\n') {
            if(c != ' ') 
                return false;
            while(c == ' ') {
                ++offset;
                ++matched;
                c = line.charAt(offset);
            }
        }
        this.matched = matched;
        return true;
    }

    public boolean isOpenCodeFence(StringBuilder line, int offset, char fenceChar) {
        int matched = 0;
        char c;
        while((c = line.charAt(offset)) == fenceChar) {
            ++offset;
            ++matched;
        }
        if(matched < 3)
            return false;
        this.level = matched;
        while(line.charAt(offset) == ' ') {
            ++offset;
            ++matched;
        }
        this.matched = matched;
        while((c = line.charAt(offset)) != '\n') {
            if(c == fenceChar)
                return false;
            ++offset;
        }
        return true;
    }

    public boolean isListMarker(StringBuilder line, int offset) {
        int pos = offset;
        char c;
        while(Character.isDigit(c = line.charAt(pos)))
            ++pos;
        if(c != '.' && c != ')')
            return false;
        ++pos;
        char c2;
        if((c2=line.charAt(pos)) != ' ' && c2 != '\n')
            return false;
        this.matched = pos-offset;
        this.level = Integer.parseInt(line.substring(offset, pos-1));
        this.bulletChar = c;
        return true;
    }
    
    private static final String CDATA = "CDATA[";
    
    public static int scanHtmlTag(StringBuilder input, int offset) {
        char c;
        c = input.charAt(offset++);        
        
        // Comment, declaration or cdata 
        if(c == '!') {
            if(offset == input.length())
                return -1;
            c = input.charAt(offset++);
            
            // Comment
            if(c == '-') {
                if(offset+4 > input.length())
                    return -1;
                if(input.charAt(offset++) != '-')
                    return -1;
                c = input.charAt(offset++);
                if(c == '-') {
                    c = input.charAt(offset++);
                    if(c == '-')
                        return -1;
                }
                if(c == '>')
                    return -1;
                
                while(offset+3 <= input.length()) {
                    c = input.charAt(offset++);
                    if(c == '-') {
                        c = input.charAt(offset++);
                        if(c == '-') {
                            c = input.charAt(offset++);
                            if(c == '>')
                                return offset;
                            else
                                return -1;
                        }
                    }
                }
                return -1;
            }
            
            // Cdata
            else if(c == '[') {
                for(int i=0;i<CDATA.length();++i) {
                    c = input.charAt(offset++);
                    if(CDATA.charAt(i) != c)
                        return -1;
                }
                while(offset+3 <= input.length()) {
                    c = input.charAt(offset++);
                    if(c == ']') {
                        c = input.charAt(offset++);
                        while(c == ']') {
                            c = input.charAt(offset++);
                            if(c == '>')
                                return offset;
                        }
                    }
                }
                return -1;
            }
            
            // Declaration
            else if(c >= 'A' && c <= 'Z') {
                while( offset < input.length() && (c=input.charAt(offset++)) >= 'A' && c <= 'Z' );
                if(c != ' ' && c != '\n')
                    return -1;
                while( offset < input.length() && (c=input.charAt(offset++)) != '>' );
                if(c != '>')
                    return -1;
                else
                    return offset;
            }
            else
                return -1;
        }
        
        // Processing instruction
        else if(c == '?') {
            while(offset < input.length()) {
                c = input.charAt(offset++);
                if(c == '?') {
                    c = input.charAt(offset++);
                    if(c == '>')
                        return offset;
                }
            }
            return -1;
        }
        
        // Close tag
        else if(c == '/') {
            offset = scanTagName(input, offset);
            if(offset == -1)
                return -1;
            offset = scanWhitespace(input, offset);
            if(offset == -1)
                return -1;
            if(input.charAt(offset) == '>')
                return offset+1;
            else
                return -1;
        }
        
        // Open tag
        else {
            --offset;
            offset = scanTagName(input, offset);
            if(offset == -1)
                return -1;
            while(true) {
                if((c=input.charAt(offset)) != ' ' && c != '\n') {
                    if(c == '>')
                        return offset+1;
                    if(c == '/' && input.charAt(offset+1)=='>')
                        return offset+2;
                    return -1;
                }
                offset = scanWhitespace(input, offset);
                if(offset == -1)
                    return -1;
                c = input.charAt(offset);
                if(c == '>')
                    return offset+1;
                if(c == '/' && input.charAt(offset+1)=='>')
                    return offset+2;
                offset = scanAttributeName(input, offset);
                if(offset == -1)
                    return -1;
                offset = scanWhitespace(input, offset);
                if(offset == -1)
                    return -1;
                if((c=input.charAt(offset)) == '=') {
                    ++offset;
                    offset = scanWhitespace(input, offset);
                    if(offset == -1)
                        return -1;
                    
                    c = input.charAt(offset);
                    if(c == '"') {
                        ++offset;
                        while(true) {
                            if(offset == input.length())
                                return -1;
                            c=input.charAt(offset++);
                            if(c == '"')
                                break;
                        }
                    }
                    else if(c == '\'') {
                        ++offset;
                        while(true) {
                            if(offset == input.length())
                                return -1;
                            c=input.charAt(offset++);
                            if(c == '\'')
                                break;
                        }
                    }
                    else {
                        while(true) {
                            if(offset == input.length())
                                return -1;
                            c=input.charAt(offset++);
                            if(c==' ' || c=='\n' || c=='"' || c=='\'' || c=='=' || c=='<' || c=='>' || c=='`') {
                                --offset;
                                break;
                            }
                        }
                    }
                }
                else {
                    if(c == '>')
                        return offset+1;
                    --offset;
                    c = input.charAt(offset);
                    if(c != ' ' && c != '\n' && c != '>')
                        return -1;
                }
            }
        }
    }
    
    private static int scanTagName(StringBuilder input, int offset) {
        if(offset >= input.length())
            return -1;
        char c = input.charAt(offset++);
        if( !((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z')) )
            return -1;
        while(offset < input.length()) {
            c = input.charAt(offset++);
            if( !((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || (c >= '0' && c <= '9')) )
                return offset-1;
        }
        return -1;
    }
    
    private static int scanAttributeName(StringBuilder input, int offset) {
        if(offset >= input.length())
            return -1;
        char c = input.charAt(offset++);
        if( !((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || c == '_' || c == ':') )
            return -1;
        while(offset < input.length()) {
            c = input.charAt(offset++);
            if( !((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || (c >= '0' && c <= '9')
                    || c == '_' || c == ':' || c == '.' || c == '-') )
                return offset-1;
        }
        return -1;
    }
    
    public static int scanWhitespace(StringBuilder input, int offset) {
        while(offset < input.length()) {
            char c = input.charAt(offset);
            if(c != ' ' && c != '\n')
                return offset;
            ++offset;
        }
        return -1;
    }

    public static int scanUri(StringBuilder input, int pos) {
        int startPos = pos;
        char c;
        while(true) {
            if(pos == input.length())
                return -1;
            c = input.charAt(pos++);
            if(c < 0 || c >= 128 || !IS_SCHEME_CHAR[(int)c])
                break;
        }
        if(c != ':' || !SCHEME_SET.contains(input.substring(startPos, pos-1).toLowerCase()))
            return -1;
        while(pos < input.length() && (c = input.charAt(pos)) != '>' && c != '<' && !(c <= 0x20 && c >= 0))
            ++pos;
        if(c == '>')
            return pos+1;
        else
            return -1;
    }
    
    private static final String[] SCHEMES = new String[] {
        "coap", "doi", "javascript", "aaa", "aaas", "about", "acap", "cap", "cid", "crid", "data", "dav", "dict", "dns", "file", "ftp", "geo", "go",
        "gopher", "h323", "http", "https", "iax", "icap", "im", "imap", "info", "ipp", "iris", "iris.beep", "iris.xpc", "iris.xpcs", "iris.lwz",
        "ldap", "mailto", "mid", "msrp", "msrps", "mtqp", "mupdate", "news", "nfs", "ni", "nih", "nntp", "opaquelocktoken", "pop", "pres", "rtsp",
        "service", "session", "shttp", "sieve", "sip", "sips", "sms", "snmp", "soap.beep", "soap.beeps", "tag", "tel", "telnet", "tftp", "thismessage",
        "tn3270", "tip", "tv", "urn", "vemmi", "ws", "wss", "xcon", "xcon-userid", "xmlrpc.beep", "xmlrpc.beeps", "xmpp", "z39.50r", "z39.50s", "adiumxtra",
        "afp", "afs", "aim", "apt", "attachment", "aw", "beshare", "bitcoin", "bolo", "callto", "chrome", "chrome-extension", "com-eventbrite-attendee",
        "content", "cvs", "dlna-playsingle", "dlna-playcontainer", "dtn", "dvb", "ed2k", "facetime", "feed", "finger", "fish", "gg", "git", "gizmoproject",
        "gtalk", "hcp", "icon", "ipn", "irc", "irc6", "ircs", "itms", "jar", "jms", "keyparc", "lastfm", "ldaps", "magnet", "maps", "market", "message", "mms",
        "ms-help", "msnim", "mumble", "mvn", "notes", "oid", "palm", "paparazzi", "platform", "proxy", "psyc", "query", "res", "resource", "rmi", "rsync",
        "rtmp", "secondlife", "sftp", "sgn", "skype", "smb", "soldat", "spotify", "ssh", "steam", "svn", "teamspeak", "things", "udp", "unreal", "ut2004",
        "ventrilo", "view-source", "webcal", "wtai", "wyciwyg", "xfire", "xri", "ymsgr"  
    };
    private static final THashSet<String> SCHEME_SET = new THashSet<String>();
    private static final boolean[] IS_SCHEME_CHAR = new boolean[128];
    static {
        for(String scheme : SCHEMES) {
            SCHEME_SET.add(scheme);
            for(int i=0;i<scheme.length();++i) {
                char c = scheme.charAt(i);
                IS_SCHEME_CHAR[(int)c] = true;
                IS_SCHEME_CHAR[(int)Character.toUpperCase(c)] = true;
            }
        }
    }
    
    public static int scanLinkLabel(StringBuilder input, int offset) {
        if(offset == input.length() || input.charAt(offset++) != '[')
            return -1;
        int maxPos = Math.min(input.length(), offset+1000);
        while(offset < maxPos) {
            char c = input.charAt(offset++);
            if(c == ']')
                return offset;
            if(c == '[')
                return -1;
            if(c == '\\' && offset < maxPos) {
                c = input.charAt(offset);
                if(Subject.getCharType(c) == 2)
                    ++offset;
            }
        }
        return -1;
    }
    
    public static int scanLinkUrl(StringBuilder input, int offset) {        
        if(offset == input.length())
            return offset;
        if(input.charAt(offset) == '<') {
            ++offset;
            while(offset < input.length()) {
                char c = input.charAt(offset++);
                if(c == '>') {
                    return offset;
                }
                else if(c == '\\') {
                    if(Subject.getCharType(c) == 2)
                        ++offset;
                }
                else if(c == '<' || c == '\n')
                    return -1;
            }
            return -1;
        }
        else {
            while(offset < input.length()) {
                char c = input.charAt(offset++);
                if(c == '\\') {
                    if(Subject.getCharType(input.charAt(offset)) == 2)
                        ++offset;
                    else
                        return offset - 1;
                }
                else if( c == '(' ) {
                    int orgPos = offset - 1;
                    while(true) {
                        if(offset >= input.length())
                            return orgPos;
                        c = input.charAt(offset++);
                        if(c == '\\') {
                            if(Subject.getCharType(input.charAt(offset)) == 2)
                                ++offset;
                            else
                                return orgPos;
                        }
                        else if(c == ')')
                            break;
                        else if( (c <= 0x20 && c >= 0) || c == '(' )
                            return orgPos;
                    }
                }
                else if( (c <= 0x20 && c >= 0) || c == ')' )
                    return offset-1;
            }
            return offset;
        }
    }

    public static int scanLinkTitle(StringBuilder input, int offset) {
        if(offset == input.length())
            return -1;
        char c = input.charAt(offset++);
        if(c == '(') {
            while(offset < input.length()) {
                c = input.charAt(offset++);
                if(c == ')')
                    return offset;      
                if(c == '\\') {
                    c = input.charAt(offset);
                    if(c == ')' || c == '\\')
                        ++offset;
                }
            }
            return -1;
        }
        else if(c == '"') {
            while(offset < input.length()) {
                c = input.charAt(offset++);
                if(c == '"')
                    return offset;      
                if(c == '\\') {
                    c = input.charAt(offset);
                    if(c == '"' || c == '\\')
                        ++offset;
                }
            }
            return -1;
        }
        if(c == '\'') {
            while(offset < input.length()) {
                c = input.charAt(offset++);
                if(c == '\'')
                    return offset;      
                if(c == '\\') {
                    c = input.charAt(offset);
                    if(c == '\'' || c == '\\')
                        ++offset;
                }
            }
            return -1;
        }
        else
            return -1;
    }
    
    private static final CharacterSet EMAIL_START = new CharacterSet("a-zA-Z0-9.!#$%&'*+/=?^_`{|}~-");
    private static final CharacterSet EMAIL_END_A = new CharacterSet("a-zA-Z0-9");
    private static final CharacterSet EMAIL_END_B = new CharacterSet("a-zA-Z0-9-");

    public static int scanEmail(StringBuilder input, int offset) {
        int initialPos = offset;
        char c = 0;
        while(offset < input.length() && EMAIL_START.contains(c=input.charAt(offset++)) );
        if( c != '@' || offset == initialPos )
            return -1;
        ++offset;
        while(true) {
            if(offset == input.length() || !EMAIL_END_A.contains(c=input.charAt(offset++)))
                return -1;
            int count = 1;
            int oldC = c;
            while(offset < input.length() && EMAIL_END_B.contains(c=input.charAt(offset++))) {
                ++count;
                if(count > 62)
                    return -1;
                oldC = c;
            }
            if(oldC=='-')
                return -1;
            if(c == '>')
                return offset;
            if(c != '.')
                return -1;
        }
    }
}