package com.mitchellbosecke.pebble.lexer;

import java.util.regex.Pattern;

/**
 * The syntax describes the different syntax parts of the Pebble language.
 *
 * <p>
 * This object is immutable after the creation. This is to make sure the syntax
 * cannot be changed during the execution.
 */
public final class Syntax {

    private final String delimiterCommentOpen;

    private final String delimiterCommentClose;

    private final String delimiterExecuteOpen;

    private final String delimiterExecuteClose;

    private final String delimiterPrintOpen;

    private final String delimiterPrintClose;

    private final String delimiterInterpolationOpen;

    private final String delimiterInterpolationClose;

    private final String whitespaceTrim;

    /**
     * The regular expressions used to find the different delimiters
     */
    private final Pattern regexPrintClose;

    private final Pattern regexExecuteClose;

    private final Pattern regexCommentClose;

    private final Pattern regexStartDelimiters;

    private final Pattern regexLeadingWhitespaceTrim;

    private final Pattern regexTrailingWhitespaceTrim;

    private final Pattern regexInterpolationOpen;
    private final Pattern regexInterpolationClose;

    /**
     * Regular expressions used to find "verbatim" and "endverbatim" tags.
     */
    private final Pattern regexVerbatimStart;

    private final Pattern regexVerbatimEnd;

    private static final String POSSIBLE_NEW_LINE = "(\r\n|\n\r|\r|\n|\u0085|\u2028|\u2029)?";

    public Syntax(final String delimiterCommentOpen, final String delimiterCommentClose,
            final String delimiterExecuteOpen, final String delimiterExecuteClose, final String delimiterPrintOpen,
            final String delimiterPrintClose, final String delimiterInterpolationOpen,
            final String delimiterInterpolationClose, final String whitespaceTrim,
            final boolean enableNewLineTrimming) {
        this.delimiterCommentClose = delimiterCommentClose;
        this.delimiterCommentOpen = delimiterCommentOpen;
        this.delimiterExecuteOpen = delimiterExecuteOpen;
        this.delimiterExecuteClose = delimiterExecuteClose;
        this.delimiterPrintOpen = delimiterPrintOpen;
        this.delimiterPrintClose = delimiterPrintClose;
        this.whitespaceTrim = whitespaceTrim;
        this.delimiterInterpolationClose = delimiterInterpolationClose;
        this.delimiterInterpolationOpen = delimiterInterpolationOpen;

        // Do we trim the newline following a tag?
        String newlineRegexSuffix = enableNewLineTrimming ? POSSIBLE_NEW_LINE : "";

        // regexes used to find the individual delimiters
        this.regexPrintClose = Pattern.compile("^\\s*" + Pattern.quote(whitespaceTrim) + "?"
                + Pattern.quote(delimiterPrintClose) + newlineRegexSuffix);

        this.regexExecuteClose = Pattern.compile("^\\s*" + Pattern.quote(whitespaceTrim) + "?"
                + Pattern.quote(delimiterExecuteClose) + newlineRegexSuffix);
        this.regexCommentClose = Pattern.compile(Pattern.quote(delimiterCommentClose) + newlineRegexSuffix);

        // combination regex used to find the next START delimiter of any kind
        this.regexStartDelimiters = Pattern.compile(Pattern.quote(delimiterPrintOpen) + "|"
                + Pattern.quote(delimiterExecuteOpen) + "|" + Pattern.quote(delimiterCommentOpen));

        // regex to find the verbatim tag
        this.regexVerbatimStart = Pattern.compile("^\\s*verbatim\\s*(" + Pattern.quote(whitespaceTrim) + ")?"
                + Pattern.quote(delimiterExecuteClose) + newlineRegexSuffix);
        this.regexVerbatimEnd = Pattern.compile(Pattern.quote(delimiterExecuteOpen) + "("
                + Pattern.quote(whitespaceTrim) + ")?" + "\\s*endverbatim\\s*(" + Pattern.quote(whitespaceTrim) + ")?"
                + Pattern.quote(delimiterExecuteClose) + newlineRegexSuffix);

        // regex for the whitespace trim character
        this.regexLeadingWhitespaceTrim = Pattern.compile(Pattern.quote(whitespaceTrim) + "\\s+");
        this.regexTrailingWhitespaceTrim = Pattern.compile("^\\s*" + Pattern.quote(whitespaceTrim) + "("
                + Pattern.quote(delimiterPrintClose) + "|" + Pattern.quote(delimiterExecuteClose) + "|"
                + Pattern.quote(delimiterCommentClose) + ")");

        this.regexInterpolationOpen = Pattern.compile("^" + Pattern.quote(delimiterInterpolationOpen));
        this.regexInterpolationClose = Pattern.compile("^\\s*" + Pattern.quote(delimiterInterpolationClose));

    }

    /**
     * @return the commentOpenDelimiter
     */
    public String getCommentOpenDelimiter() {
        return delimiterCommentOpen;
    }

    /**
     * @return the commentCloseDelimiter
     */
    public String getCommentCloseDelimiter() {
        return delimiterCommentClose;
    }

    /**
     * @return the executeOpenDelimiter
     */
    public String getExecuteOpenDelimiter() {
        return delimiterExecuteOpen;
    }

    /**
     * @return the executeCloseDelimiter
     */
    public String getExecuteCloseDelimiter() {
        return delimiterExecuteClose;
    }

    /**
     * @return the printOpenDelimiter
     */
    public String getPrintOpenDelimiter() {
        return delimiterPrintOpen;
    }

    /**
     * @return the printCloseDelimiter
     */
    public String getPrintCloseDelimiter() {
        return delimiterPrintClose;
    }

    public String getInterpolationOpenDelimiter() {
        return delimiterInterpolationOpen;
    }

    public String getInterpolationCloseDelimiter() {
        return delimiterInterpolationClose;
    }

    public String getWhitespaceTrim() {
        return whitespaceTrim;
    }

    Pattern getRegexPrintClose() {
        return regexPrintClose;
    }

    Pattern getRegexExecuteClose() {
        return regexExecuteClose;
    }

    Pattern getRegexCommentClose() {
        return regexCommentClose;
    }

    Pattern getRegexStartDelimiters() {
        return regexStartDelimiters;
    }

    Pattern getRegexLeadingWhitespaceTrim() {
        return regexLeadingWhitespaceTrim;
    }

    Pattern getRegexTrailingWhitespaceTrim() {
        return regexTrailingWhitespaceTrim;
    }

    Pattern getRegexVerbatimEnd() {
        return regexVerbatimEnd;
    }

    Pattern getRegexVerbatimStart() {
        return regexVerbatimStart;
    }

    Pattern getRegexInterpolationOpen() {
        return regexInterpolationOpen;
    }

    Pattern getRegexInterpolationClose() {
        return regexInterpolationClose;
    }

    /**
     * Helper class to create new instances of {@link Syntax}.
     */
    public static class Builder {

        private String delimiterCommentOpen = "{#";

        private String delimiterCommentClose = "#}";

        private String delimiterExecuteOpen = "{%";

        private String delimiterExecuteClose = "%}";

        private String delimiterPrintOpen = "{{";

        private String delimiterPrintClose = "}}";

        private String delimiterInterpolationOpen = "#{";

        private String delimiterInterpolationClose = "}";

        private String whitespaceTrim = "-";

        private boolean enableNewLineTrimming = true;

        /**
         * @return the commentOpenDelimiter
         */
        public String getCommentOpenDelimiter() {
            return delimiterCommentOpen;
        }

        /**
         * @param commentOpenDelimiter
         *            the commentOpenDelimiter to set
         * @return This builder object
         */
        public Builder setCommentOpenDelimiter(String commentOpenDelimiter) {
            this.delimiterCommentOpen = commentOpenDelimiter;
            return this;
        }

        /**
         * @return the commentCloseDelimiter
         */
        public String getCommentCloseDelimiter() {
            return delimiterCommentClose;
        }

        /**
         * @param commentCloseDelimiter
         *            the commentCloseDelimiter to set
         * @return This builder object
         */
        public Builder setCommentCloseDelimiter(String commentCloseDelimiter) {
            this.delimiterCommentClose = commentCloseDelimiter;
            return this;
        }

        /**
         * @return the executeOpenDelimiter
         */
        public String getExecuteOpenDelimiter() {
            return delimiterExecuteOpen;
        }

        /**
         * @param executeOpenDelimiter
         *            the executeOpenDelimiter to set
         * @return This builder object
         */
        public Builder setExecuteOpenDelimiter(String executeOpenDelimiter) {
            this.delimiterExecuteOpen = executeOpenDelimiter;
            return this;
        }

        /**
         * @return the executeCloseDelimiter
         */
        public String getExecuteCloseDelimiter() {
            return delimiterExecuteClose;
        }

        /**
         * @param executeCloseDelimiter
         *            the executeCloseDelimiter to set
         * @return This builder object
         */
        public Builder setExecuteCloseDelimiter(String executeCloseDelimiter) {
            this.delimiterExecuteClose = executeCloseDelimiter;
            return this;
        }

        /**
         * @return the printOpenDelimiter
         */
        public String getPrintOpenDelimiter() {
            return delimiterPrintOpen;
        }

        /**
         * @param printOpenDelimiter
         *            the printOpenDelimiter to set
         * @return This builder object
         */
        public Builder setPrintOpenDelimiter(String printOpenDelimiter) {
            this.delimiterPrintOpen = printOpenDelimiter;
            return this;
        }

        /**
         * @return the printCloseDelimiter
         */
        public String getPrintCloseDelimiter() {
            return delimiterPrintClose;
        }

        /**
         * @param printCloseDelimiter
         *            the printCloseDelimiter to set
         * @return This builder object
         */
        public Builder setPrintCloseDelimiter(String printCloseDelimiter) {
            this.delimiterPrintClose = printCloseDelimiter;
            return this;
        }

        public String getWhitespaceTrim() {
            return whitespaceTrim;
        }

        public Builder setWhitespaceTrim(String whitespaceTrim) {
            this.whitespaceTrim = whitespaceTrim;
            return this;
        }

        public String getInterpolationOpenDelimiter() {
            return delimiterInterpolationOpen;
        }

        public void setInterpolationOpenDelimiter(String delimiterInterpolationOpen) {
            this.delimiterInterpolationOpen = delimiterInterpolationOpen;
        }

        public String getInterpolationCloseDelimiter() {
            return delimiterInterpolationClose;
        }

        public void setInterpolationCloseDelimiter(String delimiterInterpolationClose) {
            this.delimiterInterpolationClose = delimiterInterpolationClose;
        }

        public boolean isEnableNewLineTrimming() {
            return enableNewLineTrimming;
        }

        public Builder setEnableNewLineTrimming(boolean enableNewLineTrimming) {
            this.enableNewLineTrimming = enableNewLineTrimming;
            return this;
        }

        public Syntax build() {
            return new Syntax(delimiterCommentOpen, delimiterCommentClose, delimiterExecuteOpen, delimiterExecuteClose,
                    delimiterPrintOpen, delimiterPrintClose, delimiterInterpolationOpen, delimiterInterpolationClose,
                    whitespaceTrim, enableNewLineTrimming);
        }
    }

}
