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package jdk.javadoc.internal.doclets.toolkit.util;

Abstraction for simple relative URIs, consisting of a path and an optional fragment. DocLink objects can be created by the constructors below or from a DocPath using the convenience fragment method. 
This is NOT part of any supported API.
 If you write code that depends on this, you do so at your own risk.
 This code and its internal interfaces are subject to change or
 deletion without notice.
/**
 * Abstraction for simple relative URIs, consisting of a path and an
 * optional fragment. DocLink objects can be created by the constructors
 * below or from a DocPath using the convenience
 * {@link DocPath#fragment fragment} method.
 *
 *  <p><b>This is NOT part of any supported API.
 *  If you write code that depends on this, you do so at your own risk.
 *  This code and its internal interfaces are subject to change or
 *  deletion without notice.</b>
 *
 */
public class DocLink {
    final DocPath path;
    final String fragment;

    
Creates a DocLink representing the URI #fragment. 
Params:
fragment – the fragment
Returns:
the DocLink/**
     * Creates a DocLink representing the URI {@code #fragment}.
     * @param fragment the fragment
     * @return the DocLink
     */
    public static DocLink fragment(String fragment) {
        return new DocLink((DocPath) null, fragment);
    }

    
Creates a DocLink representing the URI path. 
Params:
path – the path/**
     * Creates a DocLink representing the URI {@code path}.
     * @param path the path
     */
    public DocLink(DocPath path) {
        this(path, null);
    }

    
Creates a DocLink representing the URI path#fragment. Any of the component parts may be null. 
Params:
path – the path
fragment – the fragment/**
     * Creates a DocLink representing the URI {@code path#fragment}.
     * Any of the component parts may be null.
     * @param path the path
     * @param fragment the fragment
     */
    public DocLink(DocPath path, String fragment) {
        this.path = path;
        this.fragment = fragment;
    }

    
Creates a DocLink representing the URI path#fragment. Any of the component parts may be null. 
Params:
path – the path
fragment – the fragment/**
     * Creates a DocLink representing the URI {@code path#fragment}.
     * Any of the component parts may be null.
     * @param path the path
     * @param fragment the fragment
     */
    public DocLink(String path, String fragment) {
        this(DocPath.create(path), fragment);
    }

    
Creates a DocLink formed by relativizing the path against a given base.
Params:
base – the base
Returns:
the DocLink/**
     * Creates a DocLink formed by relativizing the path against a given base.
     * @param base the base
     * @return the DocLink
     */
    public DocLink relativizeAgainst(DocPath base) {
        if (base.isEmpty() || path == null) {
            return this;
        }

        // The following guards against the (ugly) use-case of using DocPath to contain a URL
        if (isAbsoluteURL(path)) {
            return this;
        }

        DocPath newPath = base.relativize(path);
        // avoid generating an empty link by using the basename of the path if necessary
        if (newPath.isEmpty() && isEmpty(fragment)) {
            newPath = path.basename();
        }
        return new DocLink(newPath, fragment);
    }

    // return true if the path begins <letters>://
    private boolean isAbsoluteURL(DocPath path) {
        String s = path.getPath();
        for (int i = 0; i < s.length(); i++) {
            char c = s.charAt(i);
            if (Character.isLetter(c)) {
                continue;
            }
            return (c == ':' && i + 2 < s.length() && s.charAt(i + 1)== '/' && s.charAt(i + 2)== '/');
        }
        return false;
    }

    
Returns the link in the form "path#fragment", omitting any empty
components.
Returns:
the string/**
     * Returns the link in the form "path#fragment", omitting any empty
     * components.
     * @return the string
     */
    @Override
    public String toString() {
        // common fast path
        if (path != null && isEmpty(fragment))
            return path.getPath();

        StringBuilder sb = new StringBuilder();
        if (path != null)
            sb.append(path.getPath());
        if (!isEmpty(fragment))
            sb.append("#").append(fragment);
        return sb.toString();
    }

    private static boolean isEmpty(String s) {
        return (s == null) || s.isEmpty();
    }
}