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package com.oracle.truffle.llvm.runtime.types;

import java.math.BigInteger;

import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
import com.oracle.truffle.llvm.runtime.CommonNodeFactory;
import com.oracle.truffle.llvm.runtime.GetStackSpaceFactory;
import com.oracle.truffle.llvm.runtime.NodeFactory;
import com.oracle.truffle.llvm.runtime.datalayout.DataLayout;
import com.oracle.truffle.llvm.runtime.except.LLVMParserException;
import com.oracle.truffle.llvm.runtime.nodes.api.LLVMExpressionNode;
import com.oracle.truffle.llvm.runtime.types.visitors.TypeVisitor;

public final class VariableBitWidthType extends Type {

    
Minimum number of bits that can be specified.
See Also:

     *      LLVM IntergerType.MIN_INT_BITS/**
     * Minimum number of bits that can be specified.
     *
     * @see <a href=
     *      "https://github.com/llvm/llvm-project/blob/llvmorg-9.0.0/llvm/include/llvm/IR/DerivedTypes.h#L51">
     *      LLVM IntergerType.MIN_INT_BITS</a>
     */
    public static final int MIN_INT_BITS = 1;
    
Maximum number of bits that can be specified.
See Also:

     *      LLVM IntergerType.MAX_INT_BITS/**
     * Maximum number of bits that can be specified.
     *
     * @see <a href=
     *      "https://github.com/llvm/llvm-project/blob/llvmorg-9.0.0/llvm/include/llvm/IR/DerivedTypes.h#L52">
     *      LLVM IntergerType.MAX_INT_BITS</a>
     */
    public static final int MAX_INT_BITS = (1 << 24) - 1;

    private final int bitWidth;
    private final Object constant;

    public VariableBitWidthType(int bitWidth) {
        this(bitWidth, null);
    }

    VariableBitWidthType(int bitWidth, Object constant) {
        if (bitWidth < MIN_INT_BITS || bitWidth > MAX_INT_BITS) {
            throw new LLVMParserException(getClass().getSimpleName() + " out of range: " + bitWidth);
        }
        this.bitWidth = bitWidth;
        this.constant = constant;
    }

    public Object getConstant() {
        return constant;
    }

    public boolean isConstant() {
        return constant != null;
    }

    @Override
    public long getBitSize() {
        return bitWidth;
    }

    public int getBitSizeInt() {
        return bitWidth;
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + bitWidth;
        result = prime * result + ((constant == null) ? 0 : constant.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj == null) {
            return false;
        }
        if (getClass() != obj.getClass()) {
            return false;
        }
        VariableBitWidthType other = (VariableBitWidthType) obj;
        if (bitWidth != other.bitWidth) {
            return false;
        }
        if (constant == null) {
            if (other.constant != null) {
                return false;
            }
        } else if (!constant.equals(other.constant)) {
            return false;
        }
        return true;
    }

    @Override
    public void accept(TypeVisitor visitor) {
        visitor.visit(this);
    }

    @Override
    public int getAlignment(DataLayout targetDataLayout) {
        if (targetDataLayout != null) {
            return targetDataLayout.getBitAlignment(this) / Byte.SIZE;

        } else if (bitWidth <= Byte.SIZE) {
            return Byte.BYTES;

        } else if (bitWidth <= Short.SIZE) {
            return Short.BYTES;

        } else if (bitWidth <= Integer.SIZE) {
            return Integer.BYTES;

        } else {
            return Long.BYTES;
        }
    }

    @Override
    public long getSize(DataLayout targetDataLayout) {
        try {
            return targetDataLayout.getSize(this);
        } catch (TypeOverflowException e) {
            // should not reach here
            throw new AssertionError(e);
        }
    }

    public int getSizeInt(DataLayout targetDataLayout) {
        long size = getSize(targetDataLayout);
        assert (int) size == size;
        return (int) size;
    }

    @Override
    @TruffleBoundary
    public String toString() {
        if (getConstant() != null) {
            return String.format("i%d %s", getBitSize(), getConstant());
        } else {
            return String.format("i%d", getBitSize());
        }
    }

    @Override
    public LLVMExpressionNode createNullConstant(NodeFactory nodeFactory, DataLayout dataLayout, GetStackSpaceFactory stackFactory) {
        return CommonNodeFactory.createSimpleConstantNoArray(BigInteger.ZERO, this);
    }
}