/*

 * Copyright (c) 2015, 2016, 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.Arrays;

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

import static jdk.jshell.Util.DOIT_METHOD_NAME;

/**

 * Wrapping of source into Java methods, fields, etc.  All but outer layer

 * wrapping with imports and class.

 *

 * @author Robert Field

 */

abstract class Wrap implements GeneralWrap {

    private static Wrap methodWrap(String prefix, String source, String suffix) {

        Wrap wunit = new NoWrap(source);

        return new DoitMethodWrap(new CompoundWrap(prefix, wunit, suffix));

    }

    public static Wrap methodWrap(String source) {

        return methodWrap("", source, semi(source) + "        return null;\n");

    }

    public static Wrap methodReturnWrap(String source) {

        return methodWrap("return ", source, semi(source));

    }

    public static Wrap methodUnreachableSemiWrap(String source) {

        return methodWrap("", source, semi(source));

    }

    public static Wrap methodUnreachableWrap(String source) {

        return methodWrap("", source, "");

    }

    private static String indent(int n) {

        return "                              ".substring(0, n * 4);

    }

    private static String nlindent(int n) {

        return "\n" + indent(n);

    }

    /**

     *

     * @param in

     * @param rname

     * @param rinit Initializer or null

     * @param rdecl Type name and name

     * @return

     */

    public static Wrap varWrap(String source, Range rtype, String brackets, Range rname, Range rinit) {

        RangeWrap wname = new RangeWrap(source, rname);

        RangeWrap wtype = new RangeWrap(source, rtype);

        Wrap wVarDecl = new VarDeclareWrap(wtype, brackets, wname);

        Wrap wmeth;

        if (rinit == null) {

            wmeth = new CompoundWrap(new NoWrap(" "), "   return null;\n");

        } else {

            RangeWrap winit = new RangeWrap(source, rinit);

        // int x = y

            // int x_ = y; return x = x_;

            // decl + "_ = " + init ; + "return " + name + "=" + name + "_ ;"

            wmeth = new CompoundWrap(

                    wtype, brackets + " ", wname, "_ =\n        ", winit, semi(winit),

                    "        return ", wname, " = ", wname, "_;\n"

            );

        }

        Wrap wInitMeth = new DoitMethodWrap(wmeth);

        return new CompoundWrap(wVarDecl, wInitMeth);

    }

    public static Wrap tempVarWrap(String source, String typename, String name) {

        RangeWrap winit = new NoWrap(source);

        // y

        // return $1 = y;

        // "return " + $1 + "=" + init ;

        Wrap wmeth = new CompoundWrap("return " + name + " =\n        ", winit, semi(winit));

        Wrap wInitMeth = new DoitMethodWrap(wmeth);

        String varDecl = "    public static\n    " + typename + " " + name + ";\n";

        return new CompoundWrap(varDecl, wInitMeth);

    }

    public static Wrap simpleWrap(String source) {

        return new NoWrap(source);

    }

    public static Wrap classMemberWrap(String source) {

        Wrap w = new NoWrap(source);

        return new CompoundWrap("    public static\n    ", w);

    }

    private static int countLines(String s) {

        return countLines(s, 0, s.length());

    }

    private static int countLines(String s, int from, int toEx) {

        int cnt = 0;

        int idx = from;

        while ((idx = s.indexOf('\n', idx)) > 0) {

            if (idx >= toEx) break;

            ++cnt;

            ++idx;

        }

        return cnt;

    }

    public static final class Range {

        final int begin;

        final int end;

        Range(int begin, int end) {

            this.begin = begin;

            this.end = end;

        }

        Range(String s) {

            this.begin = 0;

            this.end = s.length();

        }

        String part(String s) {

            return s.substring(begin, end);

        }

        int length() {

            return end - begin;

        }

        boolean isEmpty() {

            return end == begin;

        }

        void verify(String s) {

            if (begin < 0 || end <= begin || end > s.length()) {

                throw new InternalError("Bad Range: " + s + "[" + begin + "," + end + "]");

            }

        }

        @Override

        public String toString() {

            return "Range[" + begin + "," + end + "]";

        }

    }

    public static class CompoundWrap extends Wrap {

        final Object[] os;

        final String wrapped;

        final int snidxFirst;

        final int snidxLast;

        final int snlineFirst;

        final int snlineLast;

        CompoundWrap(Object... os) {

            this.os = os;

            int sniFirst = Integer.MAX_VALUE;

            int sniLast = Integer.MIN_VALUE;

            int snlnFirst = Integer.MAX_VALUE;

            int snlnLast = Integer.MIN_VALUE;

            StringBuilder sb = new StringBuilder();

            for (Object o : os) {

                if (o instanceof String) {

                    String s = (String) o;

                    sb.append(s);

                } else if (o instanceof Wrap) {

                    Wrap w = (Wrap) o;

                    if (w.firstSnippetIndex() < sniFirst) {

                        sniFirst = w.firstSnippetIndex();

                    }

                    if (w.lastSnippetIndex() > sniLast) {

                        sniLast = w.lastSnippetIndex();

                    }

                    if (w.firstSnippetLine() < snlnFirst) {

                        snlnFirst = w.firstSnippetLine();

                    }

                    if (w.lastSnippetLine() > snlnLast) {

                        snlnLast = w.lastSnippetLine();

                    }

                    sb.append(w.wrapped());

                } else {

                    throw new InternalError("Bad object in CommoundWrap: " + o);

                }

            }

            this.wrapped = sb.toString();

            this.snidxFirst = sniFirst;

            this.snidxLast = sniLast;

            this.snlineFirst = snlnFirst;

            this.snlineLast = snlnLast;

        }

        @Override

        public String wrapped() {

            return wrapped;

        }

        @Override

        public int snippetIndexToWrapIndex(int sni) {

            int before = 0;

            for (Object o : os) {

                if (o instanceof String) {

                    String s = (String) o;

                    before += s.length();

                } else if (o instanceof Wrap) {

                    Wrap w = (Wrap) o;

                    if (sni >= w.firstSnippetIndex() && sni <= w.lastSnippetIndex()) {

                        return w.snippetIndexToWrapIndex(sni) + before;

                    }

                    before += w.wrapped().length();

                }

            }

            return 0;

        }

        Wrap wrapIndexToWrap(long wi) {

            int before = 0;

            Wrap w = null;

            for (Object o : os) {

                if (o instanceof String) {

                    String s = (String) o;

                    before += s.length();

                } else if (o instanceof Wrap) {

                    w = (Wrap) o;

                    int len = w.wrapped().length();

                    if ((wi - before) <= len) {

                        //System.err.printf("Defer to wrap %s - wi: %d. before; %d   -- %s  >>> %s\n",

                        //        w, wi, before, w.debugPos(wi - before), w.wrapped());

                        return w;

                    }

                    before += len;

                }

            }

            return w;

        }

        @Override

        public int wrapIndexToSnippetIndex(int wi) {

            int before = 0;

            for (Object o : os) {

                if (o instanceof String) {

                    String s = (String) o;

                    before += s.length();

                } else if (o instanceof Wrap) {

                    Wrap w = (Wrap) o;

                    int len = w.wrapped().length();

                    if ((wi - before) <= len) {

                        //System.err.printf("Defer to wrap %s - wi: %d. before; %d   -- %s  >>> %s\n",

                        //        w, wi, before, w.debugPos(wi - before), w.wrapped());

                        return w.wrapIndexToSnippetIndex(wi - before);

                    }

                    before += len;

                }

            }

            return lastSnippetIndex();

        }

        @Override

        public int firstSnippetIndex() {

            return snidxFirst;

        }

        @Override

        public int lastSnippetIndex() {

            return snidxLast;

        }

        @Override

        public int snippetLineToWrapLine(int snline) {

            int before = 0;

            for (Object o : os) {

                if (o instanceof String) {

                    String s = (String) o;

                    before += countLines(s);

                } else if (o instanceof Wrap) {

                    Wrap w = (Wrap) o;

                    if (snline >= w.firstSnippetLine() && snline <= w.lastSnippetLine()) {

                        return w.snippetLineToWrapLine(snline) + before;

                    }

                    before += countLines(w.wrapped());

                }

            }

            return 0;

        }

        Wrap wrapLineToWrap(int wline) {

            int before = 0;

            Wrap w = null;

            for (Object o : os) {

                if (o instanceof String) {

                    String s = (String) o;

                    before += countLines(s);

                } else if (o instanceof Wrap) {

                    w = (Wrap) o;

                    int lns = countLines(w.wrapped());

                    if ((wline - before) < lns) {

                        return w;

                    }

                    before += lns;

                }

            }

            return w;

        }

        @Override

        public int wrapLineToSnippetLine(int wline) {

            int before = 0;

            for (Object o : os) {

                if (o instanceof String) {

                    String s = (String) o;

                    before += countLines(s);

                } else if (o instanceof Wrap) {

                    Wrap w = (Wrap) o;

                    int lns = countLines(w.wrapped());

                    if ((wline - before) < lns) {

                        return w.wrapLineToSnippetLine(wline - before);

                    }

                    before += lns;

                }

            }

            return 0;

        }

        @Override

        public int firstSnippetLine() {

            return snlineFirst;

        }

        @Override

        public int lastSnippetLine() {

            return snlineLast;

        }

        @Override

        public String toString() {

        }

    }

    private static class RangeWrap extends Wrap {

        final Range range;

        final String wrapped;

        final int firstSnline;

        final int lastSnline;

        RangeWrap(String snippetSource, Range usedWithinSnippet) {

            this.range = usedWithinSnippet;

            this.wrapped = usedWithinSnippet.part(snippetSource);

            usedWithinSnippet.verify(snippetSource);

            this.firstSnline = countLines(snippetSource, 0, range.begin);

            this.lastSnline = firstSnline + countLines(snippetSource, range.begin, range.end);

        }

        @Override

        public String wrapped() {

            return wrapped;

        }

        @Override

        public int snippetIndexToWrapIndex(int sni) {

            if (sni < range.begin) {

                return 0;

            }

            if (sni > range.end) {

                return range.length();

            }

            return sni - range.begin;

        }

        @Override

        public int wrapIndexToSnippetIndex(int wi) {

            if (wi < 0) {

                return 0; // bad index

            }

            int max = range.length();

            if (wi > max) {

                wi = max;

            }

            return wi + range.begin;

        }

        @Override

        public int firstSnippetIndex() {

            return range.begin;

        }

        @Override

        public int lastSnippetIndex() {

            return range.end;

        }

        @Override

        public int snippetLineToWrapLine(int snline) {

            if (snline < firstSnline) {

                return 0;

            }

            if (snline >= lastSnline) {

                return lastSnline - firstSnline;

            }

            return snline - firstSnline;

        }

        @Override

        public int wrapLineToSnippetLine(int wline) {

            if (wline < 0) {

                return 0; // bad index

            }

            int max = lastSnline - firstSnline;

            if (wline > max) {

                wline = max;

            }

            return wline + firstSnline;

        }

        @Override

        public int firstSnippetLine() {

            return firstSnline;

        }

        @Override

        public int lastSnippetLine() {

            return lastSnline;

        }

        @Override

        public String toString() {

            return "RangeWrap(" + range + ")";

        }

    }

    private static class NoWrap extends RangeWrap {

        NoWrap(String unit) {

            super(unit, new Range(unit));

        }

    }

    private static String semi(Wrap w) {

        return semi(w.wrapped());

    }

    private static String semi(String s) {

        return ((s.endsWith(";")) ? "\n" : ((s.endsWith(";\n")) ? "" : ";\n"));

    }

    private static class DoitMethodWrap extends CompoundWrap {

        DoitMethodWrap(Wrap w) {

            super("    public static Object " + DOIT_METHOD_NAME + "() throws Throwable {\n"

                    + "        ", w,

                    "    }\n");

        }

    }

    private static class VarDeclareWrap extends CompoundWrap {

        VarDeclareWrap(Wrap wtype, String brackets, Wrap wname) {

            super("    public static ", wtype, brackets + " ", wname, semi(wname));

        }

    }

}