/*
 * Copyright (c) 1997, 2023 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0, which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the
 * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
 * version 2 with the GNU Classpath Exception, which is available at
 * https://www.gnu.org/software/classpath/license.html.
 *
 * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
 */

package jakarta.mail.internet;

/**
 * This class represents a MIME Content-Type value. It provides
 * methods to parse a Content-Type string into individual components
 * and to generate a MIME style Content-Type string.
 *
 * @author John Mani
 */

public class ContentType {

    private String primaryType;    // primary type
    private String subType;    // subtype
    private ParameterList list;    // parameter list

    /**
     * No-arg Constructor.
     */
    public ContentType() {
    }

    /**
     * Constructor.
     *
     * @param primaryType primary type
     * @param subType     subType
     * @param list        ParameterList
     */
    public ContentType(String primaryType, String subType,
                       ParameterList list) {
        this.primaryType = primaryType;
        this.subType = subType;
        this.list = list;
    }

    /**
     * Constructor that takes a Content-Type string. The String
     * is parsed into its constituents: primaryType, subType
     * and parameters. A ParseException is thrown if the parse fails.
     *
     * @param s the Content-Type string.
     * @throws ParseException if the parse fails.
     */
    public ContentType(String s) throws ParseException {
        HeaderTokenizer h = new HeaderTokenizer(s, HeaderTokenizer.MIME);
        HeaderTokenizer.Token tk;

        // First "type" ..
        tk = h.next();
        if (tk.getType() != HeaderTokenizer.Token.ATOM)
            throw new ParseException("In Content-Type string <" + s + ">" +
                    ", expected MIME type, got " +
                    tk.getValue());
        primaryType = tk.getValue();

        // The '/' separator ..
        tk = h.next();
        if ((char) tk.getType() != '/')
            throw new ParseException("In Content-Type string <" + s + ">" +
                    ", expected '/', got " + tk.getValue());

        // Then "subType" ..
        tk = h.next();
        if (tk.getType() != HeaderTokenizer.Token.ATOM)
            throw new ParseException("In Content-Type string <" + s + ">" +
                    ", expected MIME subtype, got " +
                    tk.getValue());
        subType = tk.getValue();

        // Finally parameters ..
        String rem = h.getRemainder();
        if (rem != null)
            list = new ParameterList(rem);
    }

    /**
     * Return the primary type.
     *
     * @return the primary type
     */
    public String getPrimaryType() {
        return primaryType;
    }

    /**
     * Return the subType.
     *
     * @return the subType
     */
    public String getSubType() {
        return subType;
    }

    /**
     * Return the MIME type string, without the parameters.
     * The returned value is basically the concatenation of
     * the primaryType, the '/' character and the secondaryType.
     *
     * @return the type
     */
    public String getBaseType() {
        if (primaryType == null || subType == null)
            return "";
        return primaryType + '/' + subType;
    }

    /**
     * Return the specified parameter value. Returns <code>null</code>
     * if this parameter is absent.
     *
     * @param name the parameter name
     * @return parameter value
     */
    public String getParameter(String name) {
        if (list == null)
            return null;

        return list.get(name);
    }

    /**
     * Return a ParameterList object that holds all the available
     * parameters. Returns null if no parameters are available.
     *
     * @return ParameterList
     */
    public ParameterList getParameterList() {
        return list;
    }

    /**
     * Set the primary type. Overrides existing primary type.
     *
     * @param primaryType primary type
     */
    public void setPrimaryType(String primaryType) {
        this.primaryType = primaryType;
    }

    /**
     * Set the subType.  Replaces the existing subType.
     *
     * @param subType the subType
     */
    public void setSubType(String subType) {
        this.subType = subType;
    }

    /**
     * Set the specified parameter. If this parameter already exists,
     * it is replaced by this new value.
     *
     * @param name  parameter name
     * @param value parameter value
     */
    public void setParameter(String name, String value) {
        if (list == null)
            list = new ParameterList();

        list.set(name, value);
    }

    /**
     * Set a new ParameterList.
     *
     * @param list ParameterList
     */
    public void setParameterList(ParameterList list) {
        this.list = list;
    }

    /**
     * Retrieve a RFC2045 style string representation of
     * this Content-Type. Returns an empty string if
     * the conversion failed.
     *
     * @return RFC2045 style string
     */
    @Override
    public String toString() {
        if (primaryType == null || subType == null) // need both
            return "";

        StringBuilder sb = new StringBuilder();
        sb.append(primaryType).append('/').append(subType);
        if (list != null)
            // append the parameter list 
            // use the length of the string buffer + the length of
            // the header name formatted as follows "Content-Type: "
            sb.append(list.toString(sb.length() + 14));

        return sb.toString();
    }

    /**
     * Match with the specified ContentType object. This method
     * compares <strong>only the <code>primaryType</code> and
     * <code>subType</code> </strong>. The parameters of both operands
     * are ignored. <p>
     *
     * For example, this method will return <code>true</code> when
     * comparing the ContentTypes for <strong>"text/plain"</strong>
     * and <strong>"text/plain; charset=foobar"</strong>.
     *
     * If the <code>subType</code> of either operand is the special
     * character '*', then the subtype is ignored during the match.
     * For example, this method will return <code>true</code> when
     * comparing the ContentTypes for <strong>"text/plain"</strong>
     * and <strong>"text/*" </strong>
     *
     * @param cType ContentType to compare this against
     * @return true if it matches
     */
    public boolean match(ContentType cType) {
        // Match primaryType
        if (!((primaryType == null && cType.getPrimaryType() == null) ||
                (primaryType != null &&
                        primaryType.equalsIgnoreCase(cType.getPrimaryType()))))
            return false;

        String sType = cType.getSubType();

        // If either one of the subTypes is wildcarded, return true
        if ((subType != null && subType.startsWith("*")) ||
                (sType != null && sType.startsWith("*")))
            return true;

        // Match subType
        return (subType == null && sType == null) ||
                (subType != null && subType.equalsIgnoreCase(sType));
    }

    /**
     * Match with the specified content-type string. This method
     * compares <strong>only the <code>primaryType</code> and
     * <code>subType</code> </strong>.
     * The parameters of both operands are ignored. <p>
     *
     * For example, this method will return <code>true</code> when
     * comparing the ContentType for <strong>"text/plain"</strong>
     * with <strong>"text/plain; charset=foobar"</strong>.
     *
     * If the <code>subType</code> of either operand is the special
     * character '*', then the subtype is ignored during the match.
     * For example, this method will return <code>true</code> when
     * comparing the ContentType for <strong>"text/plain"</strong>
     * with <strong>"text/*" </strong>
     *
     * @param s the content-type string to match
     * @return true if it matches
     */
    public boolean match(String s) {
        try {
            return match(new ContentType(s));
        } catch (ParseException pex) {
            return false;
        }
    }
}
