package com.github.javaparser.ast.validator;

import com.github.javaparser.ast.body.ClassOrInterfaceDeclaration;
import com.github.javaparser.ast.body.InitializerDeclaration;
import com.github.javaparser.ast.expr.*;
import com.github.javaparser.ast.stmt.LocalClassDeclarationStmt;
import com.github.javaparser.ast.stmt.TryStmt;

import java.util.Optional;

/**
 * Contains validations that are valid for every Java version.
 * Used by default by the static JavaParser methods.
 */
public class Java1_0Validator extends Validators {
    public Java1_0Validator() {
        super(
                new VisitorValidator() {
                    @Override
                    public void visit(TryStmt n, ProblemReporter reporter) {
                        if (n.getCatchClauses().isEmpty()
                                && n.getResources().isEmpty()
                                && !n.getFinallyBlock().isPresent()) {
                            reporter.report(n, "Try has no finally, no catch, and no resources.");
                        }
                        super.visit(n, reporter);
                    }
                },
                new VisitorValidator() {
                    @Override
                    public void visit(ClassOrInterfaceDeclaration n, ProblemReporter reporter) {
                        if (!n.isInterface() && n.getExtendedTypes().size() > 1) {
                            reporter.report(n.getExtendedTypes(1), "A class cannot extend more than one other class.");
                        }
                        super.visit(n, reporter);
                    }
                },
                new VisitorValidator() {
                    @Override
                    public void visit(ClassOrInterfaceDeclaration n, ProblemReporter reporter) {
                        if (n.isInterface() && !n.getImplementedTypes().isEmpty()) {
                            reporter.report(n.getImplementedTypes(0), "An interface cannot implement other interfaces.");
                        }
                        super.visit(n, reporter);
                    }
                },
                new VisitorValidator() {
                    @Override
                    public void visit(ClassOrInterfaceDeclaration n, ProblemReporter reporter) {
                        n.getParentNode().ifPresent(p -> {
                            if (p instanceof LocalClassDeclarationStmt && n.isInterface())
                                reporter.report(n, "There is no such thing as a local interface.");
                        });
                        super.visit(n, reporter);
                    }
                },
                new VisitorValidator() {
                    @Override
                    public void visit(ClassOrInterfaceDeclaration n, ProblemReporter reporter) {
                        if (n.isInterface()) {
                            n.getMembers().forEach(mem -> {
                                if (mem instanceof InitializerDeclaration) {
                                    reporter.report(mem, "An interface cannot have initializers.");
                                }
                            });
                        }
                        super.visit(n, reporter);
                    }
                },
                new VisitorValidator() {
                    @Override
                    public void visit(ClassOrInterfaceDeclaration n, ProblemReporter reporter) {
                        if (n.isInterface()) {
                            n.getMethods().forEach(m -> {
                                if (m.isDefault() && !m.getBody().isPresent()) {
                                    reporter.report(m, "'default' methods must have a body.");
                                }
                            });
                        }
                        super.visit(n, reporter);
                    }
                },
                new VisitorValidator() {
                    @Override
                    public void visit(AssignExpr n, ProblemReporter reporter) {
                        // https://docs.oracle.com/javase/specs/jls/se8/html/jls-15.html#jls-15.26
                        Expression target = n.getTarget();
                        while (target instanceof EnclosedExpr) {
                            Optional<Expression> inner = ((EnclosedExpr) target).getInner();
                            if (!inner.isPresent()) {
                                reporter.report(n.getTarget(), "Illegal left hand side of an assignment.");
                                super.visit(n, reporter);
                                return;
                            }
                            target = inner.get();
                        }
                        if (target instanceof NameExpr
                                || target instanceof ArrayAccessExpr
                                || target instanceof FieldAccessExpr) {
                            return;
                        }
                        reporter.report(n.getTarget(), "Illegal left hand side of an assignment.");
                        super.visit(n, reporter);
                    }
                },
                new Java1_0ModifierValidator()
        );
    }
}