// Copyright (c) 2017, the R8 project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
package com.android.tools.r8.cf;

import com.android.tools.r8.cf.code.CfArrayLength;
import com.android.tools.r8.cf.code.CfArrayLoad;
import com.android.tools.r8.cf.code.CfArrayStore;
import com.android.tools.r8.cf.code.CfBinop;
import com.android.tools.r8.cf.code.CfCheckCast;
import com.android.tools.r8.cf.code.CfConstClass;
import com.android.tools.r8.cf.code.CfConstNull;
import com.android.tools.r8.cf.code.CfConstNumber;
import com.android.tools.r8.cf.code.CfConstString;
import com.android.tools.r8.cf.code.CfFieldInstruction;
import com.android.tools.r8.cf.code.CfFrame;
import com.android.tools.r8.cf.code.CfGoto;
import com.android.tools.r8.cf.code.CfIf;
import com.android.tools.r8.cf.code.CfIfCmp;
import com.android.tools.r8.cf.code.CfInstanceOf;
import com.android.tools.r8.cf.code.CfInstruction;
import com.android.tools.r8.cf.code.CfInvoke;
import com.android.tools.r8.cf.code.CfLabel;
import com.android.tools.r8.cf.code.CfLoad;
import com.android.tools.r8.cf.code.CfMonitor;
import com.android.tools.r8.cf.code.CfMultiANewArray;
import com.android.tools.r8.cf.code.CfNew;
import com.android.tools.r8.cf.code.CfNewArray;
import com.android.tools.r8.cf.code.CfNop;
import com.android.tools.r8.cf.code.CfPop;
import com.android.tools.r8.cf.code.CfPosition;
import com.android.tools.r8.cf.code.CfReturn;
import com.android.tools.r8.cf.code.CfReturnVoid;
import com.android.tools.r8.cf.code.CfStore;
import com.android.tools.r8.cf.code.CfSwitch;
import com.android.tools.r8.cf.code.CfSwitch.Kind;
import com.android.tools.r8.cf.code.CfThrow;
import com.android.tools.r8.cf.code.CfUnop;
import com.android.tools.r8.errors.Unreachable;
import com.android.tools.r8.graph.CfCode;
import com.android.tools.r8.graph.CfCode.LocalVariableInfo;
import com.android.tools.r8.graph.DebugLocalInfo;
import com.android.tools.r8.graph.DexField;
import com.android.tools.r8.graph.DexMethod;
import com.android.tools.r8.graph.DexType;
import com.android.tools.r8.ir.code.If;
import com.android.tools.r8.ir.code.MemberType;
import com.android.tools.r8.ir.code.Monitor;
import com.android.tools.r8.ir.code.NumericType;
import com.android.tools.r8.ir.code.Position;
import com.android.tools.r8.ir.code.ValueType;
import com.android.tools.r8.utils.DescriptorUtils;
import com.android.tools.r8.utils.StringUtils;
import com.android.tools.r8.utils.StringUtils.BraceType;
import it.unimi.dsi.fastutil.ints.IntList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.Type;
import org.objectweb.asm.util.Printer;

/**
 * Utility to print CF code and instructions.
 *
 * <p>This implementation prints the code formatted according to the Jasmin syntax.
 */
public class CfPrinter {

  private final String indent;
  private final Map<CfLabel, String> labels;

  private final StringBuilder builder = new StringBuilder();

  /** Entry for printing single instructions without global knowledge (eg, label numbers). */
  public CfPrinter() {
    indent = "";
    labels = null;
  }

  /** Entry for printing a complete code object. */
  public CfPrinter(CfCode code) {
    indent = "  ";
    labels = new HashMap<>();
    int nextLabelNumber = 0;
    for (CfInstruction instruction : code.getInstructions()) {
      if (instruction instanceof CfLabel) {
        labels.put((CfLabel) instruction, "L" + nextLabelNumber++);
      }
    }
    builder.append(".method ");
    appendMethod(code.getMethod());
    newline();
    builder.append(".limit stack ").append(code.getMaxStack());
    newline();
    builder.append(".limit locals ").append(code.getMaxLocals());
    for (LocalVariableInfo local : code.getLocalVariables()) {
      DebugLocalInfo info = local.getLocal();
      newline();
      builder
          .append(".var ")
          .append(local.getIndex())
          .append(" is ")
          .append(info.name)
          .append(" ")
          .append(info.type.toDescriptorString())
          .append(" from ")
          .append(getLabel(local.getStart()))
          .append(" to ")
          .append(getLabel(local.getEnd()));
      if (info.signature != null) {
        appendComment(info.signature.toString());
      }
    }
    for (CfInstruction instruction : code.getInstructions()) {
      instruction.print(this);
    }
    newline();
    builder.append(".end method");
    newline();
  }

  private void print(String name) {
    indent();
    builder.append(name);
  }

  public void print(CfNop nop) {
    print("nop");
  }

  public void print(CfThrow insn) {
    print("athrow");
  }

  public void print(CfConstNull constNull) {
    print("aconst_null");
  }

  public void print(CfConstNumber constNumber) {
    indent();
    // TODO(zerny): Determine when the number matches the tconst_X instructions.
    switch (constNumber.getType()) {
      case INT:
        builder.append("ldc ").append(constNumber.getIntValue());
        break;
      case FLOAT:
        builder.append("ldc ").append(constNumber.getFloatValue());
        break;
      case LONG:
        builder.append("ldc_w ").append(constNumber.getLongValue());
        break;
      case DOUBLE:
        builder.append("ldc_w ").append(constNumber.getDoubleValue());
        break;
      default:
        throw new Unreachable("Unexpected const-number type: " + constNumber.getType());
    }
  }

  public void print(CfConstClass constClass) {
    indent();
    builder.append("ldc ");
    appendClass(constClass.getType());
  }

  public void print(CfReturnVoid ret) {
    print("return");
  }

  public void print(CfReturn ret) {
    print(typePrefix(ret.getType()) + "return");
  }

  public void print(CfMonitor monitor) {
    print(monitor.getType() == Monitor.Type.ENTER ? "monitorenter" : "monitorexit");
  }

  public void print(CfBinop binop) {
    print(opcodeName(binop.getOpcode()));
  }

  public void print(CfUnop unop) {
    print(opcodeName(unop.getOpcode()));
  }

  public void print(CfPop pop) {
    print("pop");
  }

  public void print(CfConstString constString) {
    indent();
    builder.append("ldc ").append(constString.getString());
  }

  public void print(CfArrayLoad arrayLoad) {
    indent();
    builder.append(typePrefix(arrayLoad.getType())).append("aload");
  }

  public void print(CfArrayStore arrayStore) {
    indent();
    builder.append(typePrefix(arrayStore.getType())).append("astore");
  }

  public void print(CfInvoke invoke) {
    indent();
    builder.append(opcodeName(invoke.getOpcode())).append(' ');
    appendMethod(invoke.getMethod());
  }

  public void print(CfFrame frame) {
    StringBuilder builder = new StringBuilder("frame: ");
    StringUtils.append(builder, frame.getLocals().values(), ", ", BraceType.SQUARE);
    builder.append(' ');
    StringUtils.append(builder, frame.getStack(), ", ", BraceType.SQUARE);
    comment(builder.toString());
  }

  public void print(CfInstanceOf insn) {
    indent();
    builder.append("instanceof ");
    appendClass(insn.getType());
  }

  public void print(CfCheckCast insn) {
    indent();
    builder.append("checkcast ");
    appendClass(insn.getType());
  }

  public void print(CfFieldInstruction insn) {
    indent();
    switch (insn.getOpcode()) {
      case Opcodes.GETFIELD:
        builder.append("getfield ");
        break;
      case Opcodes.PUTFIELD:
        builder.append("putfield ");
        break;
      case Opcodes.GETSTATIC:
        builder.append("getstatic ");
        break;
      case Opcodes.PUTSTATIC:
        builder.append("putstatic ");
        break;
      default:
        throw new Unreachable("Unexpected field-instruction opcode " + insn.getOpcode());
    }
    appendField(insn.getField());
    builder.append(' ');
    appendDescriptor(insn.getField().type);
  }

  public void print(CfNew newInstance) {
    indent();
    builder.append("new ");
    appendClass(newInstance.getType());
  }

  public void print(CfNewArray newArray) {
    indent();
    String elementDescriptor = newArray.getType().toDescriptorString().substring(1);
    if (newArray.getType().isPrimitiveArrayType()) {
      // Primitive arrays are formatted as the Java type: int, byte, etc.
      builder.append("newarray ");
      builder.append(DescriptorUtils.descriptorToJavaType(elementDescriptor));
    } else {
      builder.append("anewarray ");
      if (elementDescriptor.charAt(0) == '[') {
        // Arrays of arrays are formatted using the descriptor syntax.
        builder.append(elementDescriptor);
      } else {
        // Arrays of class types are formatted using the "internal name".
        builder.append(Type.getType(elementDescriptor).getInternalName());
      }
    }
  }

  public void print(CfMultiANewArray multiANewArray) {
    indent();
    builder.append("multianewarray ");
    appendClass(multiANewArray.getType());
    builder.append(' ').append(multiANewArray.getDimensions());
  }

  public void print(CfArrayLength arrayLength) {
    print("arraylength");
  }

  public void print(CfLabel label) {
    newline();
    builder.append(getLabel(label)).append(':');
  }

  public void print(CfPosition instruction) {
    Position position = instruction.getPosition();
    indent();
    builder.append(".line ").append(position.line);
    if (position.file != null || position.callerPosition != null) {
      appendComment(position.toString());
    }
  }

  public void print(CfGoto jump) {
    indent();
    builder.append("goto ").append(getLabel(jump.getTarget()));
  }

  private String ifPostfix(If.Type kind) {
    return kind.toString().toLowerCase();
  }

  public void print(CfIf conditional) {
    indent();
    if (conditional.getType().isObject()) {
      builder.append("if").append(conditional.getKind() == If.Type.EQ ? "null" : "nonnull");
    } else {
      builder.append("if").append(ifPostfix(conditional.getKind()));
    }
    builder.append(' ').append(getLabel(conditional.getTarget()));
  }

  public void print(CfIfCmp conditional) {
    indent();
    builder
        .append(conditional.getType().isObject() ? "if_acmp" : "if_icmp")
        .append(ifPostfix(conditional.getKind()))
        .append(' ')
        .append(getLabel(conditional.getTarget()));
  }

  public void print(CfSwitch cfSwitch) {
    indent();
    builder.append(cfSwitch.getKind() == Kind.LOOKUP ? "lookup" : "table").append("switch");
    IntList keys = cfSwitch.getKeys();
    List<CfLabel> targets = cfSwitch.getTargets();
    for (int i = 0; i < keys.size(); i++) {
      indent();
      builder
          .append("  ")
          .append(keys.getInt(i))
          .append(": ")
          .append(getLabel(targets.get(i)));
    }
    indent();
    builder
        .append("  default: ")
        .append(getLabel(cfSwitch.getDefaultTarget()));
  }

  public void print(CfLoad load) {
    printPrefixed(load.getType(), "load", load.getLocalIndex());
  }

  public void print(CfStore store) {
    printPrefixed(store.getType(), "store", store.getLocalIndex());
  }

  private void printPrefixed(ValueType type, String instruction, int local) {
    indent();
    builder.append(typePrefix(type)).append(instruction).append(' ').append(local);
  }

  private char typePrefix(ValueType type) {
    switch (type) {
      case OBJECT:
        return 'a';
      case INT:
        return 'i';
      case FLOAT:
        return 'f';
      case LONG:
        return 'l';
      case DOUBLE:
        return 'd';
      default:
        throw new Unreachable("Unexpected type for prefix: " + type);
    }
  }

  public char typePrefix(MemberType type) {
    switch (type) {
      case OBJECT:
        return 'a';
      case BOOLEAN:
      case BYTE:
        return 'b';
      case CHAR:
        return 'c';
      case SHORT:
        return 's';
      case INT:
        return 'i';
      case FLOAT:
        return 'f';
      case LONG:
        return 'l';
      case DOUBLE:
        return 'd';
      default:
        throw new Unreachable("Unexpected member type for prefix: " + type);
    }
  }

  public char typePrefix(NumericType type) {
    switch (type) {
      case BYTE:
      case CHAR:
      case SHORT:
      case INT:
        return 'i';
      case FLOAT:
        return 'f';
      case LONG:
        return 'l';
      case DOUBLE:
        return 'd';
      default:
        throw new Unreachable("Unexpected numeric type for prefix: " + type);
    }
  }

  private String getLabel(CfLabel label) {
    return labels != null ? labels.get(label) : "L?";
  }

  private void newline() {
    if (builder.length() > 0) {
      builder.append('\n');
    }
  }

  private void indent() {
    newline();
    builder.append(indent);
  }

  private void comment(String comment) {
    indent();
    builder.append("; ").append(comment);
  }

  private void appendComment(String comment) {
    builder.append(" ; ").append(comment);
  }

  private void appendDescriptor(DexType type) {
    builder.append(type.toDescriptorString());
  }

  private void appendClass(DexType type) {
    builder.append(type.getInternalName());
  }

  private void appendField(DexField field) {
    appendClass(field.getHolder());
    builder.append('/').append(field.name);
  }

  private void appendMethod(DexMethod method) {
    builder.append(method.qualifiedName());
    builder.append(method.proto.toDescriptorString());
  }

  private String opcodeName(int opcode) {
    return Printer.OPCODES[opcode].toLowerCase();
  }

  @Override
  public String toString() {
    return builder.toString();
  }
}