package net.deterlab.abac;

import org.apache.commons.collections15.*;
import org.apache.commons.collections15.functors.*;

import edu.uci.ics.jung.graph.*;
import edu.uci.ics.jung.graph.event.*;
import edu.uci.ics.jung.graph.util.*;

import java.awt.geom.Point2D;
import java.io.*;
import java.util.*;
import java.util.zip.*;
import java.security.*;
import java.security.cert.*;

import org.bouncycastle.x509.*;
import org.bouncycastle.x509.util.*;
import org.bouncycastle.openssl.*;

/**
 * Represents a global graph of credentials in the form of principals and
 * attributes.
 */
public class Context {
    static final int ABAC_CERT_SUCCESS = 0;
    static final int ABAC_CERT_INVALID = -1;
    static final int ABAC_CERT_BAD_SIG = -2;
    static final int ABAC_CERT_MISSING_ISSUER = -3;

    protected Graph<Role,Credential> g;
    protected Set<Credential> derived_edges;
    protected Query pq;
    protected boolean dirty;
    protected Set<Identity> identities;

    protected Map<String, String> nicknames;
    protected Map<String, String> keys;

    public Context() {
        /* create the graph */
        g = Graphs.<Role,Credential>synchronizedDirectedGraph(
		new DirectedSparseGraph<Role,Credential>());
	derived_edges = new HashSet<Credential>();
        pq = new Query(g);
	dirty = false;
	identities = new TreeSet<Identity>();
	nicknames = new TreeMap<String, String>();
	keys = new TreeMap<String, String>();
    }

    public Context(Context c) {
	this();
	for (Identity i: c.identities) 
	    loadIDChunk(i);
	for (Credential cr: c.credentials()) 
	    loadAttributeChunk(cr);
	derive_implied_edges();
    }

    public int loadIDFile(String fn) { return loadIDFile(new File(fn)); }
    public int loadIDFile(File fn) {
	try {
	    addIdentity(new Identity(fn));
	}
	catch (SignatureException sig) {
	    return ABAC_CERT_BAD_SIG;
	}
	catch (Exception e) {
	    return ABAC_CERT_INVALID;
	}
	return ABAC_CERT_SUCCESS;
    }

    public int loadIDChunk(Object c) {
	try {
	    if (c instanceof Identity)
		addIdentity((Identity) c);
	    else if (c instanceof String) 
		addIdentity(new Identity((String) c));
	    else if (c instanceof File) 
		addIdentity(new Identity((File) c));
	    else if (c instanceof X509Certificate) 
		addIdentity(new Identity((X509Certificate) c));
	    else 
		return ABAC_CERT_INVALID;
	}
	catch (SignatureException sig) {
	    return ABAC_CERT_BAD_SIG;
	}
	catch (Exception e) {
	    return ABAC_CERT_INVALID;
	}
	return ABAC_CERT_SUCCESS;
    }

    public int loadAttributeFile(String fn) { 
	return loadAttributeFile(new File(fn));
    }

    public int loadAttributeFile(File fn) {
	try {
	    add_credential(new Credential(fn, identities));
	}
	catch (InvalidKeyException sig) {
	    return ABAC_CERT_MISSING_ISSUER;
	}
	catch (Exception e) {
	    return ABAC_CERT_INVALID;
	}
	return ABAC_CERT_SUCCESS;
    }

    public int loadAttributeChunk(Object c) {
	try {
	    if (c instanceof Credential)
		add_credential((Credential) c);
	    else if (c instanceof String) 
		add_credential(new Credential((String) c, identities));
	    else if (c instanceof File) 
		add_credential(new Credential((File) c, identities));
	    else if ( c instanceof X509V2AttributeCertificate) 
		add_credential(new Credential((X509V2AttributeCertificate)c,
			    identities));
	    else 
		return ABAC_CERT_INVALID;
	}
	catch (SignatureException sig) {
	    return ABAC_CERT_BAD_SIG;
	}
	catch (Exception e) {
	    return ABAC_CERT_INVALID;
	}
	return ABAC_CERT_SUCCESS;
    }

    public Collection<Credential> query(String role, String principal) {
	derive_implied_edges();

	Query q = new Query(g);
	Graph<Role, Credential> rg = q.run(role, principal);
	return rg.getEdges();
    }

    /**
     * Returns a collection of the credentials in the graph.
     */
    public Collection<Credential> credentials() {
        Collection<Credential> creds = new HashSet<Credential>();

        // only return creds with a cert: all others are derived edges
        for (Credential cred : g.getEdges())
            if (cred.cert() != null)
                creds.add(cred);

        return creds;
    }


    /**
     * Returns a Query object which can be used to query the graph. This object
     * becomes invalid if the graph is modified.
     */
    public Query querier() {
        derive_implied_edges();
        return new Query(g);
    }

    /**
     * Add a credential to the graph.
     */
    public void add_credential(Credential cred) {
        Role tail = cred.tail();
        Role head = cred.head();

        /* explicitly add the vertices, otherwise get a null pointer exception */
	if ( !g.containsVertex(head)) 
	    g.addVertex(head);
	if ( !g.containsVertex(tail)) 
	    g.addVertex(tail);

	if (!g.containsEdge(cred))
	    g.addEdge(cred, tail, head);

        // add the prereqs of an intersection to the graph
        if (tail.is_intersection())
            for (Role prereq : tail.prereqs())
                g.addVertex(prereq);

        dirty = true;
    }

    /**
     * Remove a credential from the graph.
     */
    public void remove_credential(Credential cred) {
	if (g.containsEdge(cred))
	    g.removeEdge(cred);
        dirty = true;
    }

    /**
     * Add a role w/o an edge
     */
    public void add_vertex(Role v) {
	if (!g.containsVertex(v)) {
	    g.addVertex(v);
	    dirty = true;
	}
    }

    public void remove_vertex(Role v) {
	if (g.containsVertex(v)) {
	    g.removeVertex(v);
	    dirty = true;
	}
    }
    public Collection<Role> roles() {
	return g.getVertices();
    }

    /**
     * Derive the implied edges in the graph, according to RT0 derivation rules.
     * They are added to this graph. See "Distributed Credential Chain Discovery
     * in Trust Management" by Ninghui Li et al. for details. Note that a
     * derived linking edge can imply a new intersection edge and vice versa.
     * Therefore we iteratively derive edges, giving up when an iteration
     * produces 0 new edges.
     */
    protected synchronized void derive_implied_edges() {
        // nothing to do on a clean graph
        if (!dirty)
            return;

        clear_old_edges();

        // iteratively derive links. continue as long as new links are added
        while (derive_links_iter() > 0)
            ;
        dirty = false;
    }

    /**
     * Single iteration of deriving implied edges. Returns the number of new
     * links added.
     */
    protected int derive_links_iter() {
        int count = 0;

        /* for every node in the graph.. */
        for (Role vertex : g.getVertices()) {
            if (vertex.is_intersection()) {
                // for each prereq edge:
                //     find set of principals that have the prereq
                // find the intersection of all sets (i.e., principals that satisfy all prereqs)
                // for each principal in intersection:
                //     add derived edge

                Set<Role> principals = null;

                for (Role prereq : vertex.prereqs()) {
                    Set<Role> cur_principals = pq.find_principals(prereq);

                    if (principals == null)
                        principals = cur_principals;
                    else
                        // no, they couldn't just call it "intersection"
                        principals.retainAll(cur_principals);

                    if (principals.size() == 0)
                        break;
                }

                // add em
                for (Role principal : principals)
                    if (add_derived_edge(vertex, principal))
                        ++count;
            }

            else if (vertex.is_linking()) {
                // make the rest of the code a bit clearer
                Role A_r1_r2 = vertex;

                Role A_r1 = new Role(A_r1_r2.A_r1());
                String r2 = A_r1_r2.r2();

                /* locate the node A.r1 */
                if (!g.containsVertex(A_r1)) continue; /* boring: nothing of the form A.r1 */

                /* for each B that satisfies A_r1 */
                for (Role principal : pq.find_principals(A_r1)) {
                    Role B_r2 = new Role(principal + "." + r2);
                    if (!g.containsVertex(B_r2)) continue;

                    if (add_derived_edge(A_r1_r2, B_r2))
                        ++count;
                }
            }
        }

        return count;
    }

    /**
     * Add a derived edge in the graph. Returns true only if the edge does not
     * exist.
     */
    protected boolean add_derived_edge(Role head, Role tail) {
        // edge exists: return false
        if (g.findEdge(tail, head) != null)
            return false;

        // add the new edge
        Credential derived_edge = new Credential(head, tail);
        derived_edges.add(derived_edge);
        g.addEdge(derived_edge, tail, head);

        return true;
    }

    /**
     * Clear the derived edges that currently exist in the graph. This is done
     * before the edges are rederived. The derived edges in filtered graphs are
     * also cleared.
     */
    protected void clear_old_edges() { 
	for (Credential i: derived_edges) 
            g.removeEdge(i);
        derived_edges = new HashSet<Credential>();
    }
    /**
     * Put the Identity into the set of ids used to validate certificates.
     * Also put the keyID and name into the translation mappings used by Roles
     * to pretty print.  In the role mapping, if multiple ids use the same
     * common name they are disambiguated.  Only one entry for keyid is
     * allowed.
     */
    protected void addIdentity(Identity id) { 
	identities.add(id);
	if (id.getName() != null && id.getKeyID() != null) {
	    if ( !keys.containsKey(id.getKeyID()) ) {
		String name = id.getName();
		int n= 1;

		while (nicknames.containsKey(name)) {
		    name = id.getName() + n++;
		}
		nicknames.put(name, id.getKeyID());
		keys.put(id.getKeyID(), name);
	    }
	}
    }
    /**
     * Translate either keys to nicknames or vice versa.  Break the string into
     * space separated tokens and then each of them into period separated
     * strings.  If any of the smallest strings is in the map, replace it with
     * the value.
     */
    protected String replace(String is, Map<String, String> m) {
	String rv = "";
	for (String tok: is.split(" ")) {
	    String term = "";
	    for (String s: tok.split("\\.")) {
		String next = m.containsKey(s) ? m.get(s) : s;

		if (term.isEmpty()) term = next;
		else term += "." + next;
	    }
	    if (rv.isEmpty()) rv = term;
	    else rv += " " + term;
	}
	return rv;
    }

    public String expandKeyID(String s) { return replace(s, nicknames); }
    public String expandNickname(String s) { return replace(s, keys); }

    /**
     * Import a zip file.  First import all the identities
     * (pem), then the credentials (der) into the credential graph then any
     * alias files into the two maps.  If keys is not null, any key pairs in
     * PEM files are put in there.  If errors is not null, errors reading files
     * are added indexed by filename.
     */
    public void readZipFile(File zf, Collection<KeyPair> keys, 
	    Map<String, Exception> errors) throws IOException {
	Vector<ZipEntry> derEntries = new Vector<ZipEntry>();
	Map<String, Identity> ids = new TreeMap<String, Identity>();
	Map<String, KeyPair> kps = new TreeMap<String, KeyPair>();

	ZipFile z = new ZipFile(zf);

	for (Enumeration<? extends ZipEntry> ze = z.entries(); 
		ze.hasMoreElements();) {
	    ZipEntry  f = ze.nextElement();
	    try {
		PEMReader r = new PEMReader(
			new InputStreamReader(z.getInputStream(f)));
		Object o = readPEM(r);

		if ( o != null ) {
		    if (o instanceof Identity) {
			Identity i = (Identity) o;
			String kid = i.getKeyID();

			if (kps.containsKey(kid) ) {
			    i.setKeyPair(kps.get(kid));
			    kps.remove(kid);
			}
			else if (i.getKeyPair() == null ) 
			    ids.put(i.getKeyID(), i);

			loadIDChunk(i);
		    }
		    else if (o instanceof KeyPair ) {
			KeyPair kp = (KeyPair) o;
			String kid = Identity.extractKeyID(kp.getPublic());

			if (ids.containsKey(kid)) {
			    Identity i = ids.get(kid);

			    i.setKeyPair(kp);
			    ids.remove(kid);
			}
			else {
			    kps.put(kid, kp);
			}
		    }
		}
		else {
		    // Not a PEM file
		    derEntries.add(f);
		    continue;
		}
	    }
	    catch (Exception e ) {
		if (errors != null ) errors.put(f.getName(), e);
	    }
	}

	for ( ZipEntry f : derEntries ) {
	    try {
		add_credential(new Credential(z.getInputStream(f), identities));
	    }
	    catch (Exception e ) {
		if (errors != null ) errors.put(f.getName(), e);
	    }
	}
    }

    public void readZipFile(File d) 
	    throws IOException {
	readZipFile(d, null, null);
    }
    public void readZipFile(File d, 
	    Map<String, Exception> errors) throws IOException {
	readZipFile(d, null, errors);
    }
    public void readZipFile(File d, 
	    Collection<KeyPair> keys) throws IOException {
	readZipFile(d, keys, null);
    }

    protected Object readPEM(PEMReader r) throws IOException {
	Identity i = null;
	KeyPair keys = null;
	Object o = null;

	while ( (o = r.readObject()) != null ) {
	    if (o instanceof X509Certificate) {
		if ( i == null ) {
		    try {
			i = new Identity((X509Certificate)o);
		    }
		    catch (Exception e) {
			// Translate Idenitiy exceptions to IOException
			throw new IOException(e);
		    }
		    if (keys != null ) {
			i.setKeyPair(keys);
			keys = null;
		    }
		}
		else throw new IOException("Two certificates");
	    }
	    else if (o instanceof KeyPair ) {
		if ( i != null ) i.setKeyPair((KeyPair) o);
		else keys = (KeyPair) o;
	    }
	    else {
		throw new IOException("Unexpected PEM object: " + 
			o.getClass().getName());
	    }
	}

	if ( i != null ) return i;
	else if ( keys != null) return keys;
	else return null;
    }

    /**
     * Import a directory full of files.  First import all the identities
     * (pem), then the credentials (der) into the credential graph then any
     * alias files into the two maps.  If keys is not null, any key pairs in
     * PEM files are put in there.  If errors is not null, errors reading files
     * are added indexed by filename.
     */
    public void readDirectory(File d, Collection<KeyPair> keys, 
	    Map<String, Exception> errors) {
	Vector<File> derFiles = new Vector<File>();
	Collection<File> files = new Vector<File>();
	Map<String, Identity> ids = new TreeMap<String, Identity>();
	Map<String, KeyPair> kps = new TreeMap<String, KeyPair>();

	if (d.isDirectory() ) 
	    for (File f : d.listFiles()) 
		files.add(f);
	else files.add(d);

	for (File f: files ) {
	    try {
		PEMReader r = new PEMReader(new FileReader(f));
		Object o = readPEM(r);

		if ( o != null ) {
		    if (o instanceof Identity) {
			Identity i = (Identity) o;
			String kid = i.getKeyID();

			if (kps.containsKey(kid) ) {
			    i.setKeyPair(kps.get(kid));
			    kps.remove(kid);
			}
			else if (i.getKeyPair() == null ) 
			    ids.put(i.getKeyID(), i);

			loadIDChunk(i);
		    }
		    else if (o instanceof KeyPair ) {
			KeyPair kp = (KeyPair) o;
			String kid = Identity.extractKeyID(kp.getPublic());

			if (ids.containsKey(kid)) {
			    Identity i = ids.get(kid);

			    i.setKeyPair(kp);
			    ids.remove(kid);
			}
			else {
			    kps.put(kid, kp);
			}
		    }
		}
		else {
		    // Not a PEM file
		    derFiles.add(f);
		    continue;
		}
	    }
	    catch (Exception e ) {
		if (errors != null ) errors.put(f.getName(), e);
	    }
	}

	for ( File f : derFiles ) {
	    try {
		add_credential(new Credential(f, identities));
	    }
	    catch (Exception e ) {
		if (errors != null ) errors.put(f.getName(), e);
	    }
	}
    }

    public void readDirectory(File d) {
	readDirectory(d, null, null);
    }
    public void readDirectory(File d, Map<String, Exception> errors) {
	readDirectory(d, null, errors);
    }
    public void readDirectory(File d, Collection<KeyPair> keys) {
	readDirectory(d, keys, null);
    }

    public void writeZipFile(File f, boolean allIDs, boolean withPrivateKeys) 
	    throws IOException {
	ZipOutputStream z = new ZipOutputStream(new FileOutputStream(f));
	Set<Identity> ids = allIDs ?  identities : new TreeSet<Identity>();

	int n = 0;
	for (Credential c: credentials()) {
	    z.putNextEntry(new ZipEntry("attr" + n++  + ".der"));
	    c.write(z);
	    z.closeEntry();
	    if ( c.getID() != null && !allIDs) ids.add(c.getID());
	}
	for (Identity i: ids) {
	    z.putNextEntry(new ZipEntry(i.getName() + ".pem"));
	    i.write(z);
	    if (withPrivateKeys)
		i.writePrivateKey(z);
	    z.closeEntry();
	}
	z.close();
    }

}