/*
 * Copyright 2012, Google Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package org.jf.dexlib2.dexbacked;

import com.google.common.io.ByteStreams;
import org.jf.dexlib2.Opcodes;
import org.jf.dexlib2.ReferenceType;
import org.jf.dexlib2.dexbacked.raw.*;
import org.jf.dexlib2.dexbacked.reference.DexBackedFieldReference;
import org.jf.dexlib2.dexbacked.reference.DexBackedMethodReference;
import org.jf.dexlib2.dexbacked.reference.DexBackedStringReference;
import org.jf.dexlib2.dexbacked.reference.DexBackedTypeReference;
import org.jf.dexlib2.dexbacked.util.FixedSizeList;
import org.jf.dexlib2.dexbacked.util.FixedSizeSet;
import org.jf.dexlib2.iface.DexFile;
import org.jf.dexlib2.iface.reference.Reference;
import org.jf.dexlib2.util.DexUtil;
import org.jf.util.ExceptionWithContext;

import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import java.io.IOException;
import java.io.InputStream;
import java.util.AbstractList;
import java.util.List;
import java.util.Set;

public class DexBackedDexFile extends BaseDexBuffer implements DexFile {
    @Nonnull private final Opcodes opcodes;

    private final int stringCount;
    private final int stringStartOffset;
    private final int typeCount;
    private final int typeStartOffset;
    private final int protoCount;
    private final int protoStartOffset;
    private final int fieldCount;
    private final int fieldStartOffset;
    private final int methodCount;
    private final int methodStartOffset;
    private final int classCount;
    private final int classStartOffset;
    private final int mapOffset;

    protected DexBackedDexFile(@Nullable Opcodes opcodes, @Nonnull byte[] buf, int offset, boolean verifyMagic) {
        super(buf, offset);

        int dexVersion;
        if (verifyMagic) {
            dexVersion = DexUtil.verifyDexHeader(buf, offset);
        } else {
            dexVersion = HeaderItem.getVersion(buf, offset);
        }

        if (opcodes == null) {
            this.opcodes = Opcodes.forDexVersion(dexVersion);
        } else {
            this.opcodes = opcodes;
        }

        stringCount = readSmallUint(HeaderItem.STRING_COUNT_OFFSET);
        stringStartOffset = readSmallUint(HeaderItem.STRING_START_OFFSET);
        typeCount = readSmallUint(HeaderItem.TYPE_COUNT_OFFSET);
        typeStartOffset = readSmallUint(HeaderItem.TYPE_START_OFFSET);
        protoCount = readSmallUint(HeaderItem.PROTO_COUNT_OFFSET);
        protoStartOffset = readSmallUint(HeaderItem.PROTO_START_OFFSET);
        fieldCount = readSmallUint(HeaderItem.FIELD_COUNT_OFFSET);
        fieldStartOffset = readSmallUint(HeaderItem.FIELD_START_OFFSET);
        methodCount = readSmallUint(HeaderItem.METHOD_COUNT_OFFSET);
        methodStartOffset = readSmallUint(HeaderItem.METHOD_START_OFFSET);
        classCount = readSmallUint(HeaderItem.CLASS_COUNT_OFFSET);
        classStartOffset = readSmallUint(HeaderItem.CLASS_START_OFFSET);
        mapOffset = readSmallUint(HeaderItem.MAP_OFFSET);

        if (dexVersion >= 41) {
          // Reject non-trivial dex container (i.e. multiples dex files in the same physical file).
          int container_off = readSmallUint(HeaderItem.CONTAINER_OFF_OFFSET);
          int container_size = readSmallUint(HeaderItem.CONTAINER_SIZE_OFFSET);
          int file_size = readSmallUint(HeaderItem.FILE_SIZE_OFFSET);
          if (container_off != 0 || container_size != file_size) {
            throw new DexUtil.UnsupportedFile(String.format("Dex container is not supported"));
          }
        }
    }

    public DexBackedDexFile(@Nullable Opcodes opcodes, @Nonnull BaseDexBuffer buf) {
        this(opcodes, buf.buf, buf.baseOffset);
    }

    public DexBackedDexFile(@Nullable Opcodes opcodes, @Nonnull byte[] buf, int offset) {
        this(opcodes, buf, offset, false);
    }

    public DexBackedDexFile(@Nullable Opcodes opcodes, @Nonnull byte[] buf) {
        this(opcodes, buf, 0, true);
    }

    @Nonnull
    public static DexBackedDexFile fromInputStream(@Nullable Opcodes opcodes, @Nonnull InputStream is)
            throws IOException {
        DexUtil.verifyDexHeader(is);

        byte[] buf = ByteStreams.toByteArray(is);
        return new DexBackedDexFile(opcodes, buf, 0, false);
    }

    @Override @Nonnull public Opcodes getOpcodes() {
        return opcodes;
    }

    // Will only be true for a dalvik-style odex file
    public boolean isOdexFile() {
        return false;
    }

    // Will be true for both a dalvik-style odex file, and an art-style odex file embedded in an oat file
    public boolean hasOdexOpcodes() {
        return false;
    }

    @Nonnull
    @Override
    public Set<? extends DexBackedClassDef> getClasses() {
        return new FixedSizeSet<DexBackedClassDef>() {
            @Nonnull
            @Override
            public DexBackedClassDef readItem(int index) {
                return new DexBackedClassDef(DexBackedDexFile.this, getClassDefItemOffset(index));
            }

            @Override
            public int size() {
                return classCount;
            }
        };
    }

    public int getStringIdItemOffset(int stringIndex) {
        if (stringIndex < 0 || stringIndex >= stringCount) {
            throw new InvalidItemIndex(stringIndex, "String index out of bounds: %d", stringIndex);
        }
        return stringStartOffset + stringIndex*StringIdItem.ITEM_SIZE;
    }

    public int getTypeIdItemOffset(int typeIndex) {
        if (typeIndex < 0 || typeIndex >= typeCount) {
            throw new InvalidItemIndex(typeIndex, "Type index out of bounds: %d", typeIndex);
        }
        return typeStartOffset + typeIndex*TypeIdItem.ITEM_SIZE;
    }

    public int getFieldIdItemOffset(int fieldIndex) {
        if (fieldIndex < 0 || fieldIndex >= fieldCount) {
            throw new InvalidItemIndex(fieldIndex, "Field index out of bounds: %d", fieldIndex);
        }
        return fieldStartOffset + fieldIndex*FieldIdItem.ITEM_SIZE;
    }

    public int getMethodIdItemOffset(int methodIndex) {
        if (methodIndex < 0 || methodIndex >= methodCount) {
            throw new InvalidItemIndex(methodIndex, "Method index out of bounds: %d", methodIndex);
        }
        return methodStartOffset + methodIndex*MethodIdItem.ITEM_SIZE;
    }

    public int getProtoIdItemOffset(int protoIndex) {
        if (protoIndex < 0 || protoIndex >= protoCount) {
            throw new InvalidItemIndex(protoIndex, "Proto index out of bounds: %d", protoIndex);
        }
        return protoStartOffset + protoIndex*ProtoIdItem.ITEM_SIZE;
    }

    public int getClassDefItemOffset(int classIndex) {
        if (classIndex < 0 || classIndex >= classCount) {
            throw new InvalidItemIndex(classIndex, "Class index out of bounds: %d", classIndex);
        }
        return classStartOffset + classIndex*ClassDefItem.ITEM_SIZE;
    }

    public int getCallSiteIdItemOffset(int callSiteIndex) {
        MapItem mapItem = getMapItemForSection(ItemType.CALL_SITE_ID_ITEM);
        if (mapItem == null || callSiteIndex >= mapItem.getItemCount()) {
            throw new InvalidItemIndex(callSiteIndex, "Call site index out of bounds: %d", callSiteIndex);
        }
        return mapItem.getOffset() + callSiteIndex * CallSiteIdItem.ITEM_SIZE;
    }

    public int getMethodHandleItemOffset(int methodHandleIndex) {
        MapItem mapItem = getMapItemForSection(ItemType.METHOD_HANDLE_ITEM);
        if (mapItem == null || methodHandleIndex >= mapItem.getItemCount()) {
            throw new InvalidItemIndex(methodHandleIndex , "Method handle index out of bounds: %d", methodHandleIndex);
        }
        return mapItem.getOffset() + methodHandleIndex * MethodHandleItem.ITEM_SIZE;
    }

    public int getClassCount() {
        return classCount;
    }

    public int getStringCount() {
        return stringCount;
    }

    public int getTypeCount() {
        return typeCount;
    }

    public int getProtoCount() {
        return protoCount;
    }

    public int getFieldCount() {
        return fieldCount;
    }

    public int getMethodCount() {
        return methodCount;
    }

    public int getCallSiteCount() {
        MapItem mapItem = getMapItemForSection(ItemType.CALL_SITE_ID_ITEM);
        if (mapItem == null) {
            return 0;
        }
        return mapItem.getItemCount();
    }

    public int getMethodHandleCount() {
        MapItem mapItem = getMapItemForSection(ItemType.METHOD_HANDLE_ITEM);
        if (mapItem == null) {
            return 0;
        }
        return mapItem.getItemCount();
    }

    @Nonnull
    public String getString(int stringIndex) {
        int stringOffset = getStringIdItemOffset(stringIndex);
        int stringDataOffset = readSmallUint(stringOffset);
        DexReader reader = readerAt(stringDataOffset);
        int utf16Length = reader.readSmallUleb128();
        return reader.readString(utf16Length);
    }

    @Nullable
    public String getOptionalString(int stringIndex) {
        if (stringIndex == -1) {
            return null;
        }
        return getString(stringIndex);
    }

    @Nonnull
    public String getType(int typeIndex) {
        int typeOffset = getTypeIdItemOffset(typeIndex);
        int stringIndex = readSmallUint(typeOffset);
        return getString(stringIndex);
    }

    @Nullable
    public String getOptionalType(int typeIndex) {
        if (typeIndex == -1) {
            return null;
        }
        return getType(typeIndex);
    }

    public List<DexBackedStringReference> getStrings() {
        return new AbstractList<DexBackedStringReference>() {
            @Override public DexBackedStringReference get(int index) {
                if (index < 0 || index >= getStringCount()) {
                    throw new IndexOutOfBoundsException();
                }
                return new DexBackedStringReference(DexBackedDexFile.this, index);
            }

            @Override public int size() {
                return getStringCount();
            }
        };
    }

    public List<DexBackedTypeReference> getTypes() {
        return new AbstractList<DexBackedTypeReference>() {
            @Override public DexBackedTypeReference get(int index) {
                if (index < 0 || index >= getTypeCount()) {
                    throw new IndexOutOfBoundsException();
                }
                return new DexBackedTypeReference(DexBackedDexFile.this, index);
            }

            @Override public int size() {
                return getTypeCount();
            }
        };
    }

    public List<DexBackedMethodReference> getMethods() {
        return new AbstractList<DexBackedMethodReference>() {
            @Override public DexBackedMethodReference get(int index) {
                if (index < 0 || index >= getMethodCount()) {
                    throw new IndexOutOfBoundsException();
                }
                return new DexBackedMethodReference(DexBackedDexFile.this, index);
            }

            @Override public int size() {
                return getMethodCount();
            }
        };
    }

    public List<DexBackedFieldReference> getFields() {
        return new AbstractList<DexBackedFieldReference>() {
            @Override public DexBackedFieldReference get(int index) {
                if (index < 0 || index >= getFieldCount()) {
                    throw new IndexOutOfBoundsException();
                }
                return new DexBackedFieldReference(DexBackedDexFile.this, index);
            }

            @Override public int size() {
                return getFieldCount();
            }
        };
    }

    public List<? extends Reference> getReferences(int referenceType) {
        switch (referenceType) {
            case ReferenceType.STRING:
                return getStrings();
            case ReferenceType.TYPE:
                return getTypes();
            case ReferenceType.METHOD:
                return getMethods();
            case ReferenceType.FIELD:
                return getFields();
            default:
                throw new IllegalArgumentException(String.format("Invalid reference type: %d", referenceType));
        }
    }

    @Override
    @Nonnull
    public DexReader readerAt(int offset) {
        return new DexReader(this, offset);
    }

    public List<MapItem> getMapItems() {
        final int mapSize = readSmallUint(mapOffset);

        return new FixedSizeList<MapItem>() {
            @Override
            public MapItem readItem(int index) {
                int mapItemOffset = mapOffset + 4 + index * MapItem.ITEM_SIZE;
                return new MapItem(DexBackedDexFile.this, mapItemOffset);
            }

            @Override public int size() {
                return mapSize;
            }
        };
    }

    @Nullable
    public MapItem getMapItemForSection(int itemType) {
        for (MapItem mapItem: getMapItems()) {
            if (mapItem.getType() == itemType) {
                return mapItem;
            }
        }
        return null;
    }

    public static class NotADexFile extends RuntimeException {
        public NotADexFile() {
        }

        public NotADexFile(Throwable cause) {
            super(cause);
        }

        public NotADexFile(String message) {
            super(message);
        }

        public NotADexFile(String message, Throwable cause) {
            super(message, cause);
        }
    }

    public static class InvalidItemIndex extends ExceptionWithContext {
        private final int itemIndex;

        public InvalidItemIndex(int itemIndex) {
            super("");
            this.itemIndex = itemIndex;
        }

        public InvalidItemIndex(int itemIndex, String message, Object... formatArgs) {
            super(message, formatArgs);
            this.itemIndex = itemIndex;
        }

        public int getInvalidIndex() {
            return itemIndex;
        }
    }
}