#include "qtscriptsyntaxhighlighter.h"
#include "style.h"
#include <QApplication>
#include <QStyle>
#include <QPlainTextEdit>

JavaScriptSyntaxHighlighter::JavaScriptSyntaxHighlighter(QTextDocument *parent)
    : QSyntaxHighlighter(parent)
    , m_markCaseSensitivity(Qt::CaseInsensitive)
{
    // https://developer.mozilla.org/en/JavaScript/Reference/Reserved_Words
    m_keywords << "break";
    m_keywords << "case";
    m_keywords << "catch";
    m_keywords << "continue";
    m_keywords << "default";
    m_keywords << "delete";
    m_keywords << "do";
    m_keywords << "else";
    m_keywords << "finally";
    m_keywords << "for";
    m_keywords << "function";
    m_keywords << "if";
    m_keywords << "in";
    m_keywords << "instanceof";
    m_keywords << "new";
    m_keywords << "return";
    m_keywords << "switch";
    m_keywords << "this";
    m_keywords << "throw";
    m_keywords << "try";
    m_keywords << "typeof";
    m_keywords << "var";
    m_keywords << "void";
    m_keywords << "while";
    m_keywords << "with";

    m_keywords << "true";
    m_keywords << "false";
    m_keywords << "null";

    // built-in and other popular objects + properties
    m_knownIds << "Object";
    m_knownIds << "prototype";
    m_knownIds << "create";
    m_knownIds << "defineProperty";
    m_knownIds << "defineProperties";
    m_knownIds << "getOwnPropertyDescriptor";
    m_knownIds << "keys";
    m_knownIds << "getOwnPropertyNames";
    m_knownIds << "constructor";
    m_knownIds << "__parent__";
    m_knownIds << "__proto__";
    m_knownIds << "__defineGetter__";
    m_knownIds << "__defineSetter__";
    m_knownIds << "eval";
    m_knownIds << "hasOwnProperty";
    m_knownIds << "isPrototypeOf";
    m_knownIds << "__lookupGetter__";
    m_knownIds << "__lookupSetter__";
    m_knownIds << "__noSuchMethod__";
    m_knownIds << "propertyIsEnumerable";
    m_knownIds << "toSource";
    m_knownIds << "toLocaleString";
    m_knownIds << "toString";
    m_knownIds << "unwatch";
    m_knownIds << "valueOf";
    m_knownIds << "watch";

    m_knownIds << "Function";
    m_knownIds << "arguments";
    m_knownIds << "arity";
    m_knownIds << "caller";
    m_knownIds << "constructor";
    m_knownIds << "length";
    m_knownIds << "name";
    m_knownIds << "apply";
    m_knownIds << "bind";
    m_knownIds << "call";

    m_knownIds << "String";
    m_knownIds << "fromCharCode";
    m_knownIds << "length";
    m_knownIds << "charAt";
    m_knownIds << "charCodeAt";
    m_knownIds << "concat";
    m_knownIds << "indexOf";
    m_knownIds << "lastIndexOf";
    m_knownIds << "localCompare";
    m_knownIds << "match";
    m_knownIds << "quote";
    m_knownIds << "replace";
    m_knownIds << "search";
    m_knownIds << "slice";
    m_knownIds << "split";
    m_knownIds << "substr";
    m_knownIds << "substring";
    m_knownIds << "toLocaleLowerCase";
    m_knownIds << "toLocaleUpperCase";
    m_knownIds << "toLowerCase";
    m_knownIds << "toUpperCase";
    m_knownIds << "trim";
    m_knownIds << "trimLeft";
    m_knownIds << "trimRight";

    m_knownIds << "Array";
    m_knownIds << "isArray";
    m_knownIds << "index";
    m_knownIds << "input";
    m_knownIds << "pop";
    m_knownIds << "push";
    m_knownIds << "reverse";
    m_knownIds << "shift";
    m_knownIds << "sort";
    m_knownIds << "splice";
    m_knownIds << "unshift";
    m_knownIds << "concat";
    m_knownIds << "join";
    m_knownIds << "filter";
    m_knownIds << "forEach";
    m_knownIds << "every";
    m_knownIds << "map";
    m_knownIds << "some";
    m_knownIds << "reduce";
    m_knownIds << "reduceRight";

    m_knownIds << "RegExp";
    m_knownIds << "global";
    m_knownIds << "ignoreCase";
    m_knownIds << "lastIndex";
    m_knownIds << "multiline";
    m_knownIds << "source";
    m_knownIds << "exec";
    m_knownIds << "test";

    m_knownIds << "JSON";
    m_knownIds << "parse";
    m_knownIds << "stringify";

    m_knownIds << "decodeURI";
    m_knownIds << "decodeURIComponent";
    m_knownIds << "encodeURI";
    m_knownIds << "encodeURIComponent";
    m_knownIds << "eval";
    m_knownIds << "isFinite";
    m_knownIds << "isNaN";
    m_knownIds << "parseFloat";
    m_knownIds << "parseInt";
    m_knownIds << "Infinity";
    m_knownIds << "NaN";
    m_knownIds << "undefined";

    m_knownIds << "Math";
    m_knownIds << "E";
    m_knownIds << "LN2";
    m_knownIds << "LN10";
    m_knownIds << "LOG2E";
    m_knownIds << "LOG10E";
    m_knownIds << "PI";
    m_knownIds << "SQRT1_2";
    m_knownIds << "SQRT2";
    m_knownIds << "abs";
    m_knownIds << "acos";
    m_knownIds << "asin";
    m_knownIds << "atan";
    m_knownIds << "atan2";
    m_knownIds << "ceil";
    m_knownIds << "cos";
    m_knownIds << "exp";
    m_knownIds << "floor";
    m_knownIds << "log";
    m_knownIds << "max";
    m_knownIds << "min";
    m_knownIds << "pow";
    m_knownIds << "random";
    m_knownIds << "round";
    m_knownIds << "sin";
    m_knownIds << "sqrt";
    m_knownIds << "tan";

    m_knownIds << "document";
    m_knownIds << "window";
    m_knownIds << "navigator";
    m_knownIds << "userAgent";

    keywordsFormat.setFontWeight(QFont::Bold);
    commentFormat.setFontItalic(true);
}

void JavaScriptSyntaxHighlighter::highlightBlock(const QString &text)
{
    // parsing state
    enum {
        Start = -1,
        Number = 1,
        Identifier = 2,
        String = 3,
        Comment = 4,
        Regex = 5
    };

    commentFormat.setForeground(QApplication::style()->standardPalette().dark());
    keywordsFormat.setForeground(QApplication::style()->standardPalette().windowText());
    keywordsFormat.setFontWeight(QFont::Bold);
    normalFormat.setForeground(QApplication::style()->standardPalette().text());
    stringFormat.setForeground(STYLE->extendedPalette().editorString());

    int state = previousBlockState();
    int start = 0;
    int i = 0;
    while (i <= text.length()) {
        QChar ch = (i < text.length()) ? text.at(i) : QChar();
        QChar next = (i < text.length() - 1) ? text.at(i + 1) : QChar();

        switch (state) {

        case Start:
            start = i;
            if (ch.isSpace()) {
                ++i;
            } else if (ch.isDigit()) {
                ++i;
                state = Number;
            } else if (ch.isLetter() || ch == '_') {
                ++i;
                state = Identifier;
            } else if (ch == '\'' || ch == '\"') {
                ++i;
                state = String;
            } else if (ch == '/' && next == '*') {
                ++i;
                ++i;
                state = Comment;
            } else if (ch == '/' && next == '/') {
                i = text.length();
                setFormat(start, text.length(), commentFormat);
            } else if (ch == '/' && next != '*') {
                ++i;
                state = Regex;
            } else {
                if (!QString("(){}[]").contains(ch))
                    setFormat(start, 1, normalFormat);
                ++i;
                state = Start;
            }
            break;

        case Number:
            if (ch.isSpace() || !ch.isDigit()) {
                setFormat(start, i - start, normalFormat);
                state = Start;
            } else {
                ++i;
            }
            break;

        case Identifier:
            if (ch.isSpace() || !(ch.isDigit() || ch.isLetter() || ch == '_')) {
                QString token = text.mid(start, i - start).trimmed();
                if (m_keywords.contains(token))
                    setFormat(start, i - start, keywordsFormat);
                else if (m_knownIds.contains(token))
                    setFormat(start, i - start, normalFormat);

                state = Start;
            } else {
                ++i;
            }
            break;

        case String:
            if (ch == text.at(start)) {
                QChar prev = (i > 0) ? text.at(i - 1) : QChar();
                if (prev != '\\') {
                    ++i;
                    setFormat(start, i - start, stringFormat);
                    state = Start;
                } else {
                    ++i;
                }
            } else {
                ++i;
            }
            break;

        case Comment:
            if (ch == '*' && next == '/') {
                ++i;
                ++i;
                setFormat(start, i - start, commentFormat);
                state = Start;
            } else {
                ++i;
            }
            break;

        case Regex:
            if (ch == '/') {
                QChar prev = (i > 0) ? text.at(i - 1) : QChar();
                if (prev != '\\') {
                    ++i;
                    setFormat(start, i - start, normalFormat);
                    state = Start;
                } else {
                    ++i;
                }
            } else {
                ++i;
            }
            break;

        default:
            state = Start;
            break;
        }
    }

    if (state == Comment)
        setFormat(start, text.length(), commentFormat);
    else
        state = Start;

    if (!m_markString.isEmpty()) {
        int pos = 0;
        int len = m_markString.length();
        QTextCharFormat markerFormat;
        markerFormat.setBackground(QApplication::style()->standardPalette().alternateBase());
        markerFormat.setForeground(QApplication::style()->standardPalette().text());
        for (;;) {
            pos = text.indexOf(m_markString, pos, m_markCaseSensitivity);
            if (pos < 0)
                break;
            setFormat(pos, len, markerFormat);
            ++pos;
        }
    }

    setCurrentBlockState(state);
}

void JavaScriptSyntaxHighlighter::mark(const QString &str, Qt::CaseSensitivity caseSensitivity)
{
    m_markString = str;
    m_markCaseSensitivity = caseSensitivity;
    rehighlight();
}


QString JavaScriptHighlighterPlugin::getLanguageName() const
{
    return QStringLiteral("QtScript");
}

QSyntaxHighlighter* JavaScriptHighlighterPlugin::createSyntaxHighlighter(QWidget* textEdit) const
{
    QPlainTextEdit* plainEdit = dynamic_cast<QPlainTextEdit*>(textEdit);
    if (plainEdit)
        return new JavaScriptSyntaxHighlighter(plainEdit->document());

    QTextEdit* edit = dynamic_cast<QTextEdit*>(textEdit);
    if (edit)
        return new JavaScriptSyntaxHighlighter(edit->document());

    return nullptr;
}