// Copyright (c) 2018, 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.utils.codeinspector;

import com.android.tools.r8.cf.code.CfInstruction;
import com.android.tools.r8.cf.code.CfPosition;
import com.android.tools.r8.code.Instruction;
import com.android.tools.r8.errors.Unimplemented;
import com.android.tools.r8.errors.Unreachable;
import com.android.tools.r8.graph.CfCode;
import com.android.tools.r8.graph.Code;
import com.android.tools.r8.graph.DexCode;
import com.android.tools.r8.graph.DexDebugEvent;
import com.android.tools.r8.graph.DexDebugInfo;
import com.android.tools.r8.graph.DexDebugPositionState;
import com.android.tools.r8.graph.DexEncodedMethod;
import com.android.tools.r8.graph.DexString;
import com.android.tools.r8.graph.JarCode;
import com.android.tools.r8.naming.MemberNaming;
import com.android.tools.r8.naming.MemberNaming.MethodSignature;
import com.android.tools.r8.naming.signature.GenericSignatureParser;
import it.unimi.dsi.fastutil.objects.Reference2IntMap;
import it.unimi.dsi.fastutil.objects.Reference2IntOpenHashMap;
import java.util.Arrays;
import java.util.Iterator;
import java.util.function.Predicate;

public class FoundMethodSubject extends MethodSubject {

  private final CodeInspector codeInspector;
  private final FoundClassSubject clazz;
  private final DexEncodedMethod dexMethod;

  public FoundMethodSubject(
      CodeInspector codeInspector, DexEncodedMethod encoded, FoundClassSubject clazz) {
    this.codeInspector = codeInspector;
    this.clazz = clazz;
    this.dexMethod = encoded;
  }

  @Override
  public boolean isPresent() {
    return true;
  }

  @Override
  public boolean isRenamed() {
    return clazz.naming != null && !getFinalSignature().name.equals(getOriginalSignature().name);
  }

  @Override
  public boolean isPublic() {
    return dexMethod.accessFlags.isPublic();
  }

  @Override
  public boolean isStatic() {
    return dexMethod.accessFlags.isStatic();
  }

  @Override
  public boolean isFinal() {
    return dexMethod.accessFlags.isFinal();
  }

  @Override
  public boolean isAbstract() {
    return dexMethod.accessFlags.isAbstract();
  }

  @Override
  public boolean isBridge() {
    return dexMethod.accessFlags.isBridge();
  }

  @Override
  public boolean isInstanceInitializer() {
    return dexMethod.isInstanceInitializer();
  }

  @Override
  public boolean isClassInitializer() {
    return dexMethod.isClassInitializer();
  }

  @Override
  public DexEncodedMethod getMethod() {
    return dexMethod;
  }

  @Override
  public MethodSignature getOriginalSignature() {
    MethodSignature signature = getFinalSignature();
    if (clazz.naming == null) {
      return signature;
    }

    // Map the parameters and return type to original names. This is needed as the in the
    // Proguard map the names on the left side are the original names. E.g.
    //
    //   X -> a
    //     X method(X) -> a
    //
    // whereas the final signature is for X.a is "a (a)"
    String[] OriginalParameters = new String[signature.parameters.length];
    for (int i = 0; i < OriginalParameters.length; i++) {
      String obfuscated = signature.parameters[i];
      String original = codeInspector.originalToObfuscatedMapping.inverse().get(obfuscated);
      OriginalParameters[i] = original != null ? original : obfuscated;
    }
    String obfuscatedReturnType = signature.type;
    String originalReturnType =
        codeInspector.originalToObfuscatedMapping.inverse().get(obfuscatedReturnType);
    String returnType = originalReturnType != null ? originalReturnType : obfuscatedReturnType;

    MethodSignature lookupSignature =
        new MethodSignature(signature.name, returnType, OriginalParameters);

    MemberNaming memberNaming = clazz.naming.lookup(lookupSignature);
    return memberNaming != null ? (MethodSignature) memberNaming.getOriginalSignature() : signature;
  }

  @Override
  public MethodSignature getFinalSignature() {
    return MethodSignature.fromDexMethod(dexMethod.method);
  }

  @Override
  public String getOriginalSignatureAttribute() {
    return codeInspector.getOriginalSignatureAttribute(
        dexMethod.annotations, GenericSignatureParser::parseMethodSignature);
  }

  @Override
  public String getFinalSignatureAttribute() {
    return codeInspector.getFinalSignatureAttribute(dexMethod.annotations);
  }

  @Override
  public Iterator<InstructionSubject> iterateInstructions() {
    return codeInspector.createInstructionIterator(this);
  }

  @Override
  public <T extends InstructionSubject> Iterator<T> iterateInstructions(
      Predicate<InstructionSubject> filter) {
    return new FilteredInstructionIterator<>(codeInspector, this, filter);
  }

  @Override
  public boolean hasLocalVariableTable() {
    Code code = getMethod().getCode();
    if (code.isDexCode()) {
      DexCode dexCode = code.asDexCode();
      if (dexCode.getDebugInfo() != null) {
        for (DexString parameter : dexCode.getDebugInfo().parameters) {
          if (parameter != null) {
            return true;
          }
        }
        for (DexDebugEvent event : dexCode.getDebugInfo().events) {
          if (event instanceof DexDebugEvent.StartLocal) {
            return true;
          }
        }
      }
      return false;
    }
    if (code.isCfCode()) {
      return !code.asCfCode().getLocalVariables().isEmpty();
    }
    if (code.isJarCode()) {
      return code.asJarCode().getNode().localVariables != null
          && !code.asJarCode().getNode().localVariables.isEmpty();
    }
    throw new Unreachable("Unexpected code type: " + code.getClass().getSimpleName());
  }

  @Override
  public LineNumberTable getLineNumberTable() {
    Code code = getMethod().getCode();
    if (code.isDexCode()) {
      return getDexLineNumberTable(code.asDexCode());
    }
    if (code.isCfCode()) {
      return getCfLineNumberTable(code.asCfCode());
    }
    if (code.isJarCode()) {
      return getJarLineNumberTable(code.asJarCode());
    }
    throw new Unreachable("Unexpected code type: " + code.getClass().getSimpleName());
  }

  private LineNumberTable getJarLineNumberTable(JarCode code) {
    throw new Unimplemented("No support for inspecting the line number table for JarCode");
  }

  private LineNumberTable getCfLineNumberTable(CfCode code) {
    int currentLine = -1;
    Reference2IntMap<InstructionSubject> lineNumberTable =
        new Reference2IntOpenHashMap<>(code.getInstructions().size());
    for (CfInstruction insn : code.getInstructions()) {
      if (insn instanceof CfPosition) {
        currentLine = ((CfPosition) insn).getPosition().line;
      }
      if (currentLine != -1) {
        lineNumberTable.put(new CfInstructionSubject(insn), currentLine);
      }
    }
    return currentLine == -1 ? null : new LineNumberTable(lineNumberTable);
  }

  private LineNumberTable getDexLineNumberTable(DexCode code) {
    DexDebugInfo debugInfo = code.getDebugInfo();
    if (debugInfo == null) {
      return null;
    }
    Reference2IntMap<InstructionSubject> lineNumberTable =
        new Reference2IntOpenHashMap<>(code.instructions.length);
    DexDebugPositionState state =
        new DexDebugPositionState(debugInfo.startLine, getMethod().method);
    Iterator<DexDebugEvent> iterator = Arrays.asList(debugInfo.events).iterator();
    for (Instruction insn : code.instructions) {
      int offset = insn.getOffset();
      while (state.getCurrentPc() < offset && iterator.hasNext()) {
        iterator.next().accept(state);
      }
      lineNumberTable.put(new DexInstructionSubject(insn), state.getCurrentLine());
    }
    return new LineNumberTable(lineNumberTable);
  }

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