package io.quarkus.qute.deployment;

import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

import org.jboss.jandex.ClassInfo;
import org.jboss.jandex.DotName;
import org.jboss.jandex.IndexView;
import org.jboss.jandex.ParameterizedType;
import org.jboss.jandex.Type;
import org.jboss.jandex.Type.Kind;
import org.jboss.jandex.TypeVariable;

import io.quarkus.arc.processor.DotNames;

public final class Types {

    static Set<Type> getTypeClosure(ClassInfo classInfo, Map<TypeVariable, Type> resolvedTypeParameters,
            IndexView index) {
        Set<Type> types = new HashSet<>();
        List<TypeVariable> typeParameters = classInfo.typeParameters();

        if (typeParameters.isEmpty() || !typeParameters.stream().allMatch(resolvedTypeParameters::containsKey)) {
            // Not a parameterized type or a raw type
            types.add(Type.create(classInfo.name(), Kind.CLASS));
        } else {
            // Canonical ParameterizedType with unresolved type variables
            Type[] typeParams = new Type[typeParameters.size()];
            for (int i = 0; i < typeParameters.size(); i++) {
                typeParams[i] = resolvedTypeParameters.get(typeParameters.get(i));
            }
            types.add(ParameterizedType.create(classInfo.name(), typeParams, null));
        }
        // Interfaces
        for (Type interfaceType : classInfo.interfaceTypes()) {
            ClassInfo interfaceClassInfo = index.getClassByName(interfaceType.name());
            if (interfaceClassInfo != null) {
                Map<TypeVariable, Type> resolved = Collections.emptyMap();
                if (Kind.PARAMETERIZED_TYPE.equals(interfaceType.kind())) {
                    resolved = buildResolvedMap(interfaceType.asParameterizedType().arguments(),
                            interfaceClassInfo.typeParameters(), resolvedTypeParameters, index);
                }
                types.addAll(getTypeClosure(interfaceClassInfo, resolved, index));
            }
        }
        // Superclass
        if (classInfo.superClassType() != null) {
            ClassInfo superClassInfo = index.getClassByName(classInfo.superName());
            if (superClassInfo != null) {
                Map<TypeVariable, Type> resolved = Collections.emptyMap();
                if (Kind.PARAMETERIZED_TYPE.equals(classInfo.superClassType().kind())) {
                    resolved = buildResolvedMap(classInfo.superClassType().asParameterizedType().arguments(),
                            superClassInfo.typeParameters(),
                            resolvedTypeParameters, index);
                }
                types.addAll(getTypeClosure(superClassInfo, resolved, index));
            }
        }
        return types;
    }

    static <T extends Type> Map<TypeVariable, Type> buildResolvedMap(List<T> resolvedArguments,
            List<TypeVariable> typeVariables,
            Map<TypeVariable, Type> resolvedTypeParameters, IndexView index) {
        Map<TypeVariable, Type> resolvedMap = new HashMap<>();
        for (int i = 0; i < resolvedArguments.size(); i++) {
            resolvedMap.put(typeVariables.get(i), resolveTypeParam(resolvedArguments.get(i), resolvedTypeParameters, index));
        }
        return resolvedMap;
    }

    static Type resolveTypeParam(Type typeParam, Map<TypeVariable, Type> resolvedTypeParameters, IndexView index) {
        if (typeParam.kind() == Kind.TYPE_VARIABLE) {
            return resolvedTypeParameters.getOrDefault(typeParam, typeParam);
        } else if (typeParam.kind() == Kind.PARAMETERIZED_TYPE) {
            ParameterizedType parameterizedType = typeParam.asParameterizedType();
            ClassInfo classInfo = index.getClassByName(parameterizedType.name());
            if (classInfo != null) {
                List<TypeVariable> typeParameters = classInfo.typeParameters();
                List<Type> arguments = parameterizedType.arguments();
                Type[] typeParams = new Type[typeParameters.size()];
                for (int i = 0; i < typeParameters.size(); i++) {
                    typeParams[i] = resolveTypeParam(arguments.get(i), resolvedTypeParameters, index);
                }
                return ParameterizedType.create(parameterizedType.name(), typeParams, null);
            }
        }
        return typeParam;
    }

    static boolean containsTypeVariable(Type type) {
        if (type.kind() == Type.Kind.TYPE_VARIABLE) {
            return true;
        }
        if (type instanceof ParameterizedType) {
            for (Type t : type.asParameterizedType().arguments()) {
                if (containsTypeVariable(t)) {
                    return true;
                }
            }
        }
        if (type.kind() == Type.Kind.ARRAY) {
            return containsTypeVariable(type.asArrayType().component());
        }
        return false;
    }

    static boolean isAssignableFrom(Type type1, Type type2, IndexView index) {
        // TODO consider type params in assignability rules
        return Types.isAssignableFrom(type1.name(), type2.name(), index);
    }

    static boolean isAssignableFrom(DotName class1, DotName class2, IndexView index) {
        // java.lang.Object is assignable from any type
        if (class1.equals(DotNames.OBJECT)) {
            return true;
        }
        // type1 is the same as type2
        if (class1.equals(class2)) {
            return true;
        }
        // type1 is a superclass
        Set<DotName> assignables = new HashSet<>();
        Collection<ClassInfo> subclasses = index.getAllKnownSubclasses(class1);
        for (ClassInfo subclass : subclasses) {
            assignables.add(subclass.name());
        }
        Collection<ClassInfo> implementors = index.getAllKnownImplementors(class1);
        for (ClassInfo implementor : implementors) {
            assignables.add(implementor.name());
        }
        return assignables.contains(class2);
    }

}
