// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
package com.jetbrains.python.inspections;

import com.intellij.codeInspection.LocalInspectionToolSession;
import com.intellij.codeInspection.LocalQuickFix;
import com.intellij.codeInspection.ProblemDescriptor;
import com.intellij.codeInspection.ProblemsHolder;
import com.intellij.codeInspection.options.OptPane;
import com.intellij.lang.ASTNode;
import com.intellij.openapi.project.Project;
import com.intellij.psi.PsiElementVisitor;
import com.intellij.psi.util.PsiTreeUtil;
import com.jetbrains.python.PyPsiBundle;
import com.jetbrains.python.PythonUiService;
import com.jetbrains.python.debugger.PySignature;
import com.jetbrains.python.debugger.PySignatureCacheManager;
import com.jetbrains.python.inspections.quickfix.PyQuickFixUtil;
import com.jetbrains.python.psi.PyFunction;
import com.jetbrains.python.psi.PyNamedParameter;
import com.jetbrains.python.psi.PyParameter;
import com.jetbrains.python.pyi.PyiUtil;
import org.jetbrains.annotations.Nls;
import org.jetbrains.annotations.NotNull;

import static com.intellij.codeInspection.options.OptPane.checkbox;
import static com.intellij.codeInspection.options.OptPane.pane;

public final class PyMissingTypeHintsInspection extends PyInspection {
  /**
   * @noinspection PublicField
   */
  public boolean m_onlyWhenTypesAreKnown = true;

  @Override
  public @NotNull PsiElementVisitor buildVisitor(@NotNull ProblemsHolder holder,
                                                 boolean isOnTheFly,
                                                 @NotNull LocalInspectionToolSession session) {
    return new PyInspectionVisitor(holder, PyInspectionVisitor.getContext(session)) {
      @Override
      public void visitPyFunction(@NotNull PyFunction function) {
        if (function.getTypeComment() == null &&
            !typeAnnotationsExist(function) &&
            PyiUtil.getOverloads(function, getResolveContext().getTypeEvalContext()).isEmpty()) {
          boolean flag = shouldRegisterProblem(function);
          if (flag) {
            ASTNode nameNode = function.getNameNode();
            if (nameNode != null) {
              registerProblem(nameNode.getPsi(),
                              PyPsiBundle.message("INSP.missing.type.hints.type.hinting.missing.for.function.definition"),
                              new AddTypeHintsQuickFix(function.getName()));
            }
          }
        }
      }
    };
  }

  private boolean shouldRegisterProblem(PyFunction function) {
    if (m_onlyWhenTypesAreKnown) {
      PySignatureCacheManager instance = PySignatureCacheManager.getInstance(function.getProject());
      if (instance != null) {
        PySignature signature = instance.findSignature(function);
        return signature != null && canAnnotate(signature);
      }
      else {
        return false;
      }
    }
    else {
      return true;
    }
  }

  private static boolean canAnnotate(@NotNull PySignature signature) {
    return !"NoneType".equals(signature.getReturnTypeQualifiedName())
           || signature.getArgs().size() > 1
           || (signature.getArgs().size() == 1 && !"self".equals(signature.getArgs().get(0).getName()));
  }

  private static boolean typeAnnotationsExist(PyFunction function) {
    for (PyParameter param : function.getParameterList().getParameters()) {
      PyNamedParameter namedParameter = param.getAsNamed();
      if (namedParameter != null) {
        if (namedParameter.getAnnotation() != null) {
          return true;
        }
      }
    }
    if (function.getAnnotation() != null) {
      return true;
    }

    return false;
  }

  @Override
  public @NotNull OptPane getOptionsPane() {
    return pane(checkbox("m_onlyWhenTypesAreKnown", PyPsiBundle.message("INSP.missing.type.hints.checkbox.only.when.types.are.known")));
  }

  private static class AddTypeHintsQuickFix implements LocalQuickFix {
    private final String myName;

    AddTypeHintsQuickFix(@NotNull String name) {
      myName = name;
    }

    @Override
    public @Nls @NotNull String getName() {
      return PyPsiBundle.message("INSP.missing.type.hints.add.type.hints.for", myName);
    }

    @Override
    public @Nls @NotNull String getFamilyName() {
      return PyPsiBundle.message("INSP.missing.type.hints.add.type.hints");
    }

    @Override
    public void applyFix(@NotNull Project project, @NotNull ProblemDescriptor descriptor) {
      PyFunction function = PsiTreeUtil.getParentOfType(descriptor.getPsiElement(), PyFunction.class);

      if (function != null) {
        PythonUiService.getInstance().annotateTypesIntention(PyQuickFixUtil.getEditor(function), function);
      }
    }
  }
}
