/*

 * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package jdk.jshell;

import java.util.ArrayList;

import java.util.Collection;

import java.util.Collections;

import java.util.HashMap;

import java.util.HashSet;

import java.util.LinkedHashSet;

import java.util.List;

import java.util.Map;

import java.util.Set;

import java.util.regex.Matcher;

import java.util.stream.Stream;

import static java.util.stream.Collectors.toList;

import static jdk.jshell.Util.PREFIX_PATTERN;

import static jdk.jshell.Util.REPL_PACKAGE;

import static jdk.internal.jshell.debug.InternalDebugControl.DBG_DEP;

/**

 * Maintain relationships between the significant entities: Snippets,

 * internal snippet index, Keys, etc.

 * @author Robert Field

 */

final class SnippetMaps {

    private final List<Snippet> keyIndexToSnippet = new ArrayList<>();

    private final Set<Snippet> snippets = new LinkedHashSet<>();

    private final Map<String, Set<Integer>> dependencies = new HashMap<>();

    private final JShell state;

    SnippetMaps(JShell proc) {

        this.state = proc;

    }

    void installSnippet(Snippet sn) {

        if (sn != null && snippets.add(sn)) {

            if (sn.key() != null) {

                sn.setId((state.idGenerator != null)

                        ? state.idGenerator.apply(sn, sn.key().index())

                        : "" + sn.key().index());

                setSnippet(sn.key().index(), sn);

            }

        }

    }

    private void setSnippet(int ki, Snippet snip) {

        while (ki >= keyIndexToSnippet.size()) {

            keyIndexToSnippet.add(null);

        }

        keyIndexToSnippet.set(ki, snip);

    }

    Snippet getSnippet(Key key) {

        return getSnippet(key.index());

    }

    Snippet getSnippet(int ki) {

        Snippet sn = getSnippetDeadOrAlive(ki);

        return (sn != null && !sn.status().isActive())

                ? null

                : sn;

    }

    Snippet getSnippetDeadOrAlive(int ki) {

        if (ki >= keyIndexToSnippet.size()) {

            return null;

        }

        return keyIndexToSnippet.get(ki);

    }

    List<Snippet> snippetList() {

        return new ArrayList<>(snippets);

    }

    String packageAndImportsExcept(Set<Key> except, Collection<Snippet> plus) {

        StringBuilder sb = new StringBuilder();

        sb.append("package ").append(REPL_PACKAGE).append(";\n");

        for (Snippet si : keyIndexToSnippet) {

            if (si != null && si.status().isDefined() && (except == null || !except.contains(si.key()))) {

                sb.append(si.importLine(state));

            }

        }

        if (plus != null) {

            plus.stream()

                    .forEach(psi -> sb.append(psi.importLine(state)));

        }

        return sb.toString();

    }

    List<Snippet> getDependents(Snippet snip) {

        if (!snip.kind().isPersistent()) {

            return Collections.emptyList();

        }

        Set<Integer> depset;

        if (snip.unitName.equals("*")) {

            // star import

            depset = new HashSet<>();

            for (Set<Integer> as : dependencies.values()) {

                depset.addAll(as);

            }

        } else {

            depset = dependencies.get(snip.name());

        }

        if (depset == null) {

            return Collections.emptyList();

        }

        List<Snippet> deps = new ArrayList<>();

        for (Integer dss : depset) {

            Snippet dep = getSnippetDeadOrAlive(dss);

            if (dep != null) {

                deps.add(dep);

                state.debug(DBG_DEP, "Found dependency %s -> %s\n", snip.name(), dep.name());

            }

        }

        return deps;

    }

    void mapDependencies(Snippet snip) {

        addDependencies(snip.declareReferences(), snip);

        addDependencies(snip.bodyReferences(),    snip);

    }

    private void addDependencies(Collection<String> refs, Snippet snip) {

        if (refs == null) return;

        for (String ref : refs) {

            dependencies.computeIfAbsent(ref, k -> new HashSet<>())

                        .add(snip.key().index());

            state.debug(DBG_DEP, "Added dependency %s -> %s\n", ref, snip.name());

        }

    }

    String fullClassNameAndPackageToClass(String full, String pkg) {

        Matcher mat = PREFIX_PATTERN.matcher(full);

        if (mat.lookingAt()) {

            return full.substring(mat.end());

        }

        state.debug(DBG_DEP, "SM %s %s\n", full, pkg);

        List<String> klasses = importSnippets()

                               .filter(isi -> !isi.isStar)

                               .map(isi -> isi.fullname)

                               .collect(toList());

        for (String k : klasses) {

            if (k.equals(full)) {

                return full.substring(full.lastIndexOf(".")+1, full.length());

            }

        }

        List<String> pkgs = importSnippets()

                               .filter(isi -> isi.isStar)

                               .map(isi -> isi.fullname.substring(0, isi.fullname.lastIndexOf(".")))

                               .collect(toList());

        pkgs.add(0, "java.lang");

        for (String ipkg : pkgs) {

            if (!ipkg.isEmpty() && ipkg.equals(pkg)) {

                return full.substring(pkg.length() + 1);

            }

        }

        return full;

    }

    /**

     * Compute the set of imports to prepend to a snippet

     * @return a stream of the import needed

     */

    private Stream<ImportSnippet> importSnippets() {

        return state.keyMap.importKeys()

                .map(key -> (ImportSnippet)getSnippet(key))

                .filter(sn -> sn != null && state.status(sn).isDefined());

    }

}