/*
 * Copyright (c) 2010, 2011, 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.
 *
 * 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 com.oracle.max.cri.ci;

import static java.lang.reflect.Modifier.*;

import java.lang.annotation.*;
import java.util.*;

import com.oracle.max.cri.ri.*;

/**
 * Miscellaneous collection of utility methods used in the {@code CRI} project.
 */
public class CiUtil {

    public static final String NEW_LINE = String.format("%n");

    /**
     * Gets the annotation of a particular type for a formal parameter of a given method.
     *
     * @param annotationClass the Class object corresponding to the annotation type
     * @param parameterIndex the index of a formal parameter of {@code method}
     * @param method the method for which a parameter annotation is being requested
     * @return the annotation of type {@code annotationClass} for the formal parameter present, else null
     * @throws IndexOutOfBoundsException if {@code parameterIndex} does not denote a formal parameter
     */
    public static <T extends Annotation> T getParameterAnnotation(Class<T> annotationClass, int parameterIndex, RiResolvedMethod method) {
        if (parameterIndex >= 0) {
            Annotation[][] parameterAnnotations = method.getParameterAnnotations();
            for (Annotation a : parameterAnnotations[parameterIndex]) {
                if (a.annotationType() == annotationClass) {
                    return annotationClass.cast(a);
                }
            }
        }
        return null;
    }

    /**
     * Extends the functionality of {@link Class#getSimpleName()} to include a non-empty string for anonymous and local
     * classes.
     *
     * @param clazz the class for which the simple name is being requested
     * @param withEnclosingClass specifies if the returned name should be qualified with the name(s) of the enclosing
     *            class/classes of {@code clazz} (if any). This option is ignored if {@code clazz} denotes an anonymous
     *            or local class.
     * @return the simple name
     */
    public static String getSimpleName(Class< ? > clazz, boolean withEnclosingClass) {
        final String simpleName = clazz.getSimpleName();
        if (simpleName.length() != 0) {
            if (withEnclosingClass) {
                String prefix = "";
                Class< ? > enclosingClass = clazz;
                while ((enclosingClass = enclosingClass.getEnclosingClass()) != null) {
                    prefix = prefix + enclosingClass.getSimpleName() + ".";
                }
                return prefix + simpleName;
            }
            return simpleName;
        }
        // Must be an anonymous or local class
        final String name = clazz.getName();
        int index = name.indexOf('$');
        if (index == -1) {
            return name;
        }
        index = name.lastIndexOf('.', index);
        if (index == -1) {
            return name;
        }
        return name.substring(index + 1);
    }

    public static final int K = 1024;
    public static final int M = 1024 * 1024;

    public static boolean isOdd(int n) {
        return (n & 1) == 1;
    }

    public static boolean isEven(int n) {
        return (n & 1) == 0;
    }

    /**
     * Checks whether the specified integer is a power of two.
     *
     * @param val the value to check
     * @return {@code true} if the value is a power of two; {@code false} otherwise
     */
    public static boolean isPowerOf2(int val) {
        return val != 0 && (val & val - 1) == 0;
    }

    /**
     * Checks whether the specified long is a power of two.
     *
     * @param val the value to check
     * @return {@code true} if the value is a power of two; {@code false} otherwise
     */
    public static boolean isPowerOf2(long val) {
        return val != 0 && (val & val - 1) == 0;
    }

    /**
     * Computes the log (base 2) of the specified integer, rounding down. (E.g {@code log2(8) = 3}, {@code log2(21) = 4}
     * )
     *
     * @param val the value
     * @return the log base 2 of the value
     */
    public static int log2(int val) {
        assert val > 0 && isPowerOf2(val);
        return 31 - Integer.numberOfLeadingZeros(val);
    }

    /**
     * Computes the log (base 2) of the specified long, rounding down. (E.g {@code log2(8) = 3}, {@code log2(21) = 4})
     *
     * @param val the value
     * @return the log base 2 of the value
     */
    public static int log2(long val) {
        assert val > 0 && isPowerOf2(val);
        return 63 - Long.numberOfLeadingZeros(val);
    }

    public static int align(int size, int align) {
        assert isPowerOf2(align);
        return (size + align - 1) & ~(align - 1);
    }

    /**
     * Gets a word with the nth bit set.
     *
     * @param n the nth bit to set
     * @return an integer value with the nth bit set
     */
    public static int nthBit(int n) {
        return n >= Integer.SIZE ? 0 : 1 << n;
    }

    /**
     * Gets a word with the right-most n bits set.
     *
     * @param n the number of right most bits to set
     * @return an integer value with the right-most n bits set
     */
    public static int rightNBits(int n) {
        return nthBit(n) - 1;
    }

    /**
     * Converts a given type to its Java programming language name. The following are examples of strings returned by
     * this method:
     *
     * <pre>
     *     qualified == true:
     *         java.lang.Object
     *         int
     *         boolean[][]
     *     qualified == false:
     *         Object
     *         int
     *         boolean[][]
     * </pre>
     *
     * @param riType the type to be converted to a Java name
     * @param qualified specifies if the package prefix of the type should be included in the returned name
     * @return the Java name corresponding to {@code riType}
     */
    public static String toJavaName(RiType riType, boolean qualified) {
        CiKind kind = riType.kind(false);
        if (kind.isPrimitive() || kind == CiKind.Void) {
            return kind.javaName;
        }
        return internalNameToJava(riType.name(), qualified);
    }

    /**
     * Converts a given type to its Java programming language name. The following are examples of strings returned by
     * this method:
     *
     * <pre>
     *      java.lang.Object
     *      int
     *      boolean[][]
     * </pre>
     *
     * @param riType the type to be converted to a Java name
     * @return the Java name corresponding to {@code riType}
     */
    public static String toJavaName(RiType riType) {
        return (riType == null) ? null : internalNameToJava(riType.name(), true);
    }

    public static String internalNameToJava(String name, boolean qualified) {
        switch (name.charAt(0)) {
            case 'L': {
                String result = name.substring(1, name.length() - 1).replace('/', '.');
                if (!qualified) {
                    final int lastDot = result.lastIndexOf('.');
                    if (lastDot != -1) {
                        result = result.substring(lastDot + 1);
                    }
                }
                return result;

            }
            case '[':
                return internalNameToJava(name.substring(1), qualified) + "[]";
            default:
                if (name.length() != 1) {
                    throw new IllegalArgumentException("Illegal internal name: " + name);
                }
                return CiKind.fromPrimitiveOrVoidTypeChar(name.charAt(0)).javaName;
        }
    }

    /**
     * Gets a string for a given method formatted according to a given format specification. A format specification is
     * composed of characters that are to be copied verbatim to the result and specifiers that denote an attribute of
     * the method that is to be copied to the result. A specifier is a single character preceded by a '%' character. The
     * accepted specifiers and the method attributes they denote are described below:
     *
     * <pre>
     *     Specifier | Description                                          | Example(s)
     *     ----------+------------------------------------------------------------------------------------------
     *     'R'       | Qualified return type                                | "int" "java.lang.String"
     *     'r'       | Unqualified return type                              | "int" "String"
     *     'H'       | Qualified holder                                     | "java.util.Map.Entry"
     *     'h'       | Unqualified holder                                   | "Entry"
     *     'n'       | Method name                                          | "add"
     *     'P'       | Qualified parameter types, separated by ', '         | "int, java.lang.String"
     *     'p'       | Unqualified parameter types, separated by ', '       | "int, String"
     *     'f'       | Indicator if method is unresolved, static or virtual | "unresolved" "static" "virtual"
     *     '%'       | A '%' character                                      | "%"
     * </pre>
     *
     * @param format a format specification
     * @param method the method to be formatted
     * @param kinds if {@code true} then the types in {@code method}'s signature are printed in the
     *            {@linkplain CiKind#jniName JNI} form of their {@linkplain CiKind kind}
     * @return the result of formatting this method according to {@code format}
     * @throws IllegalFormatException if an illegal specifier is encountered in {@code format}
     */
    public static String format(String format, RiMethod method) throws IllegalFormatException {
        final StringBuilder sb = new StringBuilder();
        int index = 0;
        RiSignature sig = null;
        while (index < format.length()) {
            final char ch = format.charAt(index++);
            if (ch == '%') {
                if (index >= format.length()) {
                    throw new UnknownFormatConversionException("An unquoted '%' character cannot terminate a method format specification");
                }
                final char specifier = format.charAt(index++);
                boolean qualified = false;
                switch (specifier) {
                    case 'R':
                        qualified = true;
                        // fall through
                    case 'r': {
                        if (sig == null) {
                            sig = method.signature();
                        }
                        sb.append(toJavaName(sig.returnType(null), qualified));
                        break;
                    }
                    case 'H':
                        qualified = true;
                        // fall through
                    case 'h': {
                        sb.append(toJavaName(method.holder(), qualified));
                        break;
                    }
                    case 'n': {
                        sb.append(method.name());
                        break;
                    }
                    case 'P':
                        qualified = true;
                        // fall through
                    case 'p': {
                        if (sig == null) {
                            sig = method.signature();
                        }
                        for (int i = 0; i < sig.argumentCount(false); i++) {
                            if (i != 0) {
                                sb.append(", ");
                            }
                            sb.append(toJavaName(sig.argumentTypeAt(i, null), qualified));
                        }
                        break;
                    }
                    case 'f': {
                        sb.append(!(method instanceof RiResolvedMethod) ? "unresolved" : isStatic(((RiResolvedMethod) method).accessFlags()) ? "static" : "virtual");
                        break;
                    }
                    case '%': {
                        sb.append('%');
                        break;
                    }
                    default: {
                        throw new UnknownFormatConversionException(String.valueOf(specifier));
                    }
                }
            } else {
                sb.append(ch);
            }
        }
        return sb.toString();
    }

    /**
     * Gets a string for a given field formatted according to a given format specification. A format specification is
     * composed of characters that are to be copied verbatim to the result and specifiers that denote an attribute of
     * the field that is to be copied to the result. A specifier is a single character preceded by a '%' character. The
     * accepted specifiers and the field attributes they denote are described below:
     *
     * <pre>
     *     Specifier | Description                                          | Example(s)
     *     ----------+------------------------------------------------------------------------------------------
     *     'T'       | Qualified type                                       | "int" "java.lang.String"
     *     't'       | Unqualified type                                     | "int" "String"
     *     'H'       | Qualified holder                                     | "java.util.Map.Entry"
     *     'h'       | Unqualified holder                                   | "Entry"
     *     'n'       | Field name                                           | "age"
     *     'f'       | Indicator if field is unresolved, static or instance | "unresolved" "static" "instance"
     *     '%'       | A '%' character                                      | "%"
     * </pre>
     *
     * @param format a format specification
     * @param field the field to be formatted
     * @param kinds if {@code true} then {@code field}'s type is printed in the {@linkplain CiKind#jniName JNI} form of
     *            its {@linkplain CiKind kind}
     * @return the result of formatting this field according to {@code format}
     * @throws IllegalFormatException if an illegal specifier is encountered in {@code format}
     */
    public static String format(String format, RiField field) throws IllegalFormatException {
        final StringBuilder sb = new StringBuilder();
        int index = 0;
        RiType type = field.type();
        while (index < format.length()) {
            final char ch = format.charAt(index++);
            if (ch == '%') {
                if (index >= format.length()) {
                    throw new UnknownFormatConversionException("An unquoted '%' character cannot terminate a field format specification");
                }
                final char specifier = format.charAt(index++);
                boolean qualified = false;
                switch (specifier) {
                    case 'T':
                        qualified = true;
                        // fall through
                    case 't': {
                        sb.append(toJavaName(type, qualified));
                        break;
                    }
                    case 'H':
                        qualified = true;
                        // fall through
                    case 'h': {
                        sb.append(toJavaName(field.holder(), qualified));
                        break;
                    }
                    case 'n': {
                        sb.append(field.name());
                        break;
                    }
                    case 'f': {
                        sb.append(!(field instanceof RiResolvedField) ? "unresolved" : isStatic(((RiResolvedField) field).accessFlags()) ? "static" : "instance");
                        break;
                    }
                    case '%': {
                        sb.append('%');
                        break;
                    }
                    default: {
                        throw new UnknownFormatConversionException(String.valueOf(specifier));
                    }
                }
            } else {
                sb.append(ch);
            }
        }
        return sb.toString();
    }

    /**
     * Gets a stack trace element for a given method and bytecode index.
     */
    public static StackTraceElement toStackTraceElement(RiMethod method, @SuppressWarnings("unused") int bci) {
        // TODO(tw): Look if we can use bci to get the line number.
        return new StackTraceElement(CiUtil.toJavaName(method.holder()), method.name(), null, -1);
    }

    /**
     * Converts a Java source-language class name into the internal form.
     *
     * @param className the class name
     * @return the internal name form of the class name
     */
    public static String toInternalName(String className) {
        return "L" + className.replace('.', '/') + ";";
    }

    /**
     * Creates a set that uses reference-equality instead of {@link Object#equals(Object)} when comparing values.
     *
     * @param <T> the type of elements in the set
     * @return a set based on reference-equality
     */
    public static <T> Set<T> newIdentityHashSet() {
        return Collections.newSetFromMap(new IdentityHashMap<T, Boolean>());
    }

    /**
     * Prepends the String {@code indentation} to every line in String {@code lines}, including a possibly non-empty
     * line following the final newline.
     */
    public static String indent(String lines, String indentation) {
        if (lines.length() == 0) {
            return lines;
        }
        final String newLine = "\n";
        if (lines.endsWith(newLine)) {
            return indentation + (lines.substring(0, lines.length() - 1)).replace(newLine, newLine + indentation) + newLine;
        }
        return indentation + lines.replace(newLine, newLine + indentation);
    }

    /**
     * Formats the values in a frame as a tabulated string.
     *
     * @param frame
     * @return the values in {@code frame} as a tabulated string
     */
    public static String tabulateValues(CiFrame frame) {
        int cols = Math.max(frame.numLocals, Math.max(frame.numStack, frame.numLocks));
        assert cols > 0;
        ArrayList<Object> cells = new ArrayList<>();
        cells.add("");
        for (int i = 0; i < cols; i++) {
            cells.add(i);
        }
        cols++;
        if (frame.numLocals != 0) {
            cells.add("locals:");
            cells.addAll(Arrays.asList(frame.values).subList(0, frame.numLocals));
            cells.addAll(Collections.nCopies(cols - frame.numLocals - 1, ""));
        }
        if (frame.numStack != 0) {
            cells.add("stack:");
            cells.addAll(Arrays.asList(frame.values).subList(frame.numLocals, frame.numLocals + frame.numStack));
            cells.addAll(Collections.nCopies(cols - frame.numStack - 1, ""));
        }
        if (frame.numLocks != 0) {
            cells.add("locks:");
            cells.addAll(Arrays.asList(frame.values).subList(frame.numLocals + frame.numStack, frame.values.length));
            cells.addAll(Collections.nCopies(cols - frame.numLocks - 1, ""));
        }
        Object[] cellArray = cells.toArray();
        for (int i = 0; i < cellArray.length; i++) {
            if ((i % cols) != 0) {
                cellArray[i] = "|" + cellArray[i];
            }
        }
        return CiUtil.tabulate(cellArray, cols, 1, 1);
    }

    /**
     * Formats a given table as a string. The value of each cell is produced by {@link String#valueOf(Object)}.
     *
     * @param cells the cells of the table in row-major order
     * @param cols the number of columns per row
     * @param lpad the number of space padding inserted before each formatted cell value
     * @param rpad the number of space padding inserted after each formatted cell value
     * @return a string with one line per row and each column left-aligned
     */
    public static String tabulate(Object[] cells, int cols, int lpad, int rpad) {
        int rows = (cells.length + (cols - 1)) / cols;
        int[] colWidths = new int[cols];
        for (int col = 0; col < cols; col++) {
            for (int row = 0; row < rows; row++) {
                int index = col + (row * cols);
                if (index < cells.length) {
                    Object cell = cells[index];
                    colWidths[col] = Math.max(colWidths[col], String.valueOf(cell).length());
                }
            }
        }
        StringBuilder sb = new StringBuilder();
        String nl = NEW_LINE;
        for (int row = 0; row < rows; row++) {
            for (int col = 0; col < cols; col++) {
                int index = col + (row * cols);
                if (index < cells.length) {
                    for (int i = 0; i < lpad; i++) {
                        sb.append(' ');
                    }
                    Object cell = cells[index];
                    String s = String.valueOf(cell);
                    int w = s.length();
                    sb.append(s);
                    while (w < colWidths[col]) {
                        sb.append(' ');
                        w++;
                    }
                    for (int i = 0; i < rpad; i++) {
                        sb.append(' ');
                    }
                }
            }
            sb.append(nl);
        }
        return sb.toString();
    }

    /**
     * Convenient shortcut for calling {@link #appendLocation(StringBuilder, RiMethod, int)} without having to supply a
     * a {@link StringBuilder} instance and convert the result to a string.
     */
    public static String toLocation(RiResolvedMethod method, int bci) {
        return appendLocation(new StringBuilder(), method, bci).toString();
    }

    /**
     * Appends a string representation of a location specified by a given method and bci to a given
     * {@link StringBuilder}. If a stack trace element with a non-null file name and non-negative line number is
     * {@linkplain RiMethod#toStackTraceElement(int) available} for the given method, then the string returned is the
     * {@link StackTraceElement#toString()} value of the stack trace element, suffixed by the bci location. For example:
     *
     * <pre>
     *     java.lang.String.valueOf(String.java:2930) [bci: 12]
     * </pre>
     *
     * Otherwise, the string returned is the value of {@code CiUtil.format("%H.%n(%p)"}, suffixed by the bci location.
     * For example:
     *
     * <pre>
     *     java.lang.String.valueOf(int) [bci: 12]
     * </pre>
     *
     * @param sb
     * @param method
     * @param bci
     * @return
     */
    public static StringBuilder appendLocation(StringBuilder sb, RiResolvedMethod method, int bci) {
        if (method != null) {
            StackTraceElement ste = method.toStackTraceElement(bci);
            if (ste.getFileName() != null && ste.getLineNumber() > 0) {
                sb.append(ste);
            } else {
                sb.append(CiUtil.format("%H.%n(%p)", method));
            }
        }
        return sb.append(" [bci: ").append(bci).append(']');
    }

    /**
     * Appends a formatted code position to a {@link StringBuilder}.
     *
     * @param sb the {@link StringBuilder} to append to
     * @param pos the code position to format and append to {@code sb}
     * @return the value of {@code sb}
     */
    public static StringBuilder append(StringBuilder sb, CiCodePos pos) {
        appendLocation(sb.append("at "), pos.method, pos.bci);
        if (pos.caller != null) {
            sb.append(NEW_LINE);
            append(sb, pos.caller);
        }
        return sb;
    }

    /**
     * Appends a formatted frame to a {@link StringBuilder}.
     *
     * @param sb the {@link StringBuilder} to append to
     * @param frame the frame to format and append to {@code sb}
     * @return the value of {@code sb}
     */
    public static StringBuilder append(StringBuilder sb, CiFrame frame) {
        appendLocation(sb.append("at "), frame.method, frame.bci);
        if (frame.values != null && frame.values.length > 0) {
            sb.append(NEW_LINE);
            String table = tabulateValues(frame);
            String[] rows = table.split(NEW_LINE);
            for (int i = 0; i < rows.length; i++) {
                String row = rows[i];
                if (!row.trim().isEmpty()) {
                    sb.append("  ").append(row);
                    if (i != rows.length - 1) {
                        sb.append(NEW_LINE);
                    }
                }
            }
        }
        if (frame.caller() != null) {
            sb.append(NEW_LINE);
            append(sb, frame.caller());
        } else if (frame.caller != null) {
            sb.append(NEW_LINE);
            append(sb, frame.caller);
        }
        return sb;
    }

    /**
     * Formats a location present in a register or frame reference map.
     */
    public static class RefMapFormatter {

        /**
         * The size of a stack slot.
         */
        public final int slotSize;

        /**
         * The register used as the frame pointer.
         */
        public final CiRegister fp;

        public final CiArchitecture arch;

        /**
         * The offset (in bytes) from the slot pointed to by {@link #fp} to the slot corresponding to bit 0 in the frame
         * reference map.
         */
        public final int refMapToFPOffset;

        public RefMapFormatter(CiArchitecture arch, int slotSize, CiRegister fp, int refMapToFPOffset) {
            this.arch = arch;
            this.slotSize = slotSize;
            this.fp = fp;
            this.refMapToFPOffset = refMapToFPOffset;
        }

        public String formatStackSlot(int frameRefMapIndex) {
            int refMapOffset = frameRefMapIndex * slotSize;
            int fpOffset = refMapOffset + refMapToFPOffset;
            if (fpOffset >= 0) {
                return fp + "+" + fpOffset;
            }
            return fp.name + fpOffset;
        }

        public String formatRegister(int regRefMapIndex) {
            return arch.registers[regRefMapIndex].toString();
        }
    }

    /**
     * Appends a formatted debug info to a {@link StringBuilder}.
     *
     * @param sb the {@link StringBuilder} to append to
     * @param info the debug info to format and append to {@code sb}
     * @return the value of {@code sb}
     */
    public static StringBuilder append(StringBuilder sb, CiDebugInfo info, RefMapFormatter formatter) {
        String nl = NEW_LINE;
        if (info.hasRegisterRefMap()) {
            sb.append("  reg-ref-map:");
            CiBitMap bm = info.registerRefMap;
            if (formatter != null) {
                for (int reg = bm.nextSetBit(0); reg >= 0; reg = bm.nextSetBit(reg + 1)) {
                    sb.append(" " + formatter.formatRegister(reg));
                }
            }
            sb.append(' ').append(bm).append(nl);
        }
        if (info.hasStackRefMap()) {
            sb.append("frame-ref-map:");
            CiBitMap bm = info.frameRefMap;
            if (formatter != null) {
                for (int i = bm.nextSetBit(0); i >= 0; i = bm.nextSetBit(i + 1)) {
                    sb.append(" " + formatter.formatStackSlot(i));
                }
            }
            sb.append(' ').append(bm).append(nl);
        }
        CiFrame frame = info.frame();
        if (frame != null) {
            append(sb, frame);
        } else if (info.codePos != null) {
            append(sb, info.codePos);
        }
        return sb;
    }

    public static CiKind[] signatureToKinds(RiResolvedMethod method) {
        CiKind receiver = isStatic(method.accessFlags()) ? null : method.holder().kind(true);
        return signatureToKinds(method.signature(), receiver);
    }

    public static CiKind[] signatureToKinds(RiSignature signature, CiKind receiverKind) {
        int args = signature.argumentCount(false);
        CiKind[] result;
        int i = 0;
        if (receiverKind != null) {
            result = new CiKind[args + 1];
            result[0] = receiverKind;
            i = 1;
        } else {
            result = new CiKind[args];
        }
        for (int j = 0; j < args; j++) {
            result[i + j] = signature.argumentKindAt(j, true);
        }
        return result;
    }

    public static Class< ? >[] signatureToTypes(RiSignature signature, RiResolvedType accessingClass) {
        int count = signature.argumentCount(false);
        Class< ? >[] result = new Class< ? >[count];
        for (int i = 0; i < result.length; ++i) {
            result[i] = signature.argumentTypeAt(i, accessingClass).resolve(accessingClass).toJava();
        }
        return result;
    }
}