package io.gitlab.jfronny.gson.compile.processor.gprocessor;

import com.squareup.javapoet.*;
import io.gitlab.jfronny.gson.compile.processor.SerializableClass;
import io.gitlab.jfronny.gson.compile.processor.adapter.Adapters;
import io.gitlab.jfronny.gson.compile.processor.core.TypeHelper;
import io.gitlab.jfronny.gson.compile.processor.core.value.*;
import io.gitlab.jfronny.gson.compile.processor.Cl;

import javax.annotation.processing.Messager;
import javax.lang.model.element.Modifier;
import javax.lang.model.element.TypeElement;
import java.io.IOException;
import java.util.List;
import java.util.Set;

public class InstanceProcessor extends GProcessor {
    public InstanceProcessor(ValueCreator valueCreator, Messager message, boolean hasManifold) {
        super(valueCreator, message, hasManifold, false);
    }

    @Override
    public void generateDelegatingAdapter(TypeSpec.Builder spec, TypeName classType, ClassName generatedClassName) {
        spec.addType(
                TypeSpec.classBuilder("Adapter")
                        .addModifiers(Modifier.PUBLIC, Modifier.STATIC)
                        .superclass(ParameterizedTypeName.get(Cl.TYPE_ADAPTER, classType))
                        .addMethod(MethodSpec.methodBuilder("write")
                                .addAnnotation(Override.class)
                                .addModifiers(Modifier.PUBLIC)
                                .addParameter(Cl.GSON_WRITER, "writer")
                                .addParameter(classType, "value")
                                .addException(IOException.class)
                                .addCode(generatedClassName.simpleName() + ".write(value, writer);")
                                .build())
                        .addMethod(MethodSpec.methodBuilder("read")
                                .addAnnotation(Override.class)
                                .addModifiers(Modifier.PUBLIC)
                                .addParameter(Cl.GSON_READER, "reader")
                                .addException(IOException.class)
                                .returns(classType)
                                .addCode("return " + generatedClassName.simpleName() + ".read(reader);")
                                .build())
                        .build()
        );
    }

    // !!!WARNING!!!
    // A lot of this code is common between InstanceProcessor and StaticProcessor
    // Make sure they don't get out of sync!
    // (Or, alternatively, create one common solution for these)
    // !!!WARNING!!!
    @Override
    public void generateSerialisation(TypeSpec.Builder spec, SerializableClass self, List<TypeVariableName> typeVariables, Set<SerializableClass> otherAdapters) throws ElementException {
        Value value = self.builder() == null ? valueCreator.from(self.classElement(), false) : valueCreator.from(TypeHelper.asDeclaredType(self.builder()).asElement(), true);
        ConstructionSource constructionSource = value.getConstructionSource();
        Properties properties = value.getProperties();

        // public static void write(JsonWriter writer, T value) throws IOException
        {
            CodeBlock.Builder code = CodeBlock.builder();
            code.beginControlFlow("if (value == null)")
                    .addStatement("writer.nullValue()")
                    .addStatement("return")
                    .endControlFlow();

            code.addStatement("writer.beginObject()");
            for (Property.Field param : properties.fields) {
                if (Properties.containsName(properties.getters, param)) continue;
                Runnable writeGet = () -> code.add("value.$N", param.getCallableName());
                if (param.getType().getKind().isPrimitive()) {
                    generateComments(param, code);
                    code.addStatement("writer.name($S)", getSerializedName(param));
                    Adapters.generateWrite(param, spec, code, typeVariables, otherAdapters, message, writeGet);
                } else {
                    code.beginControlFlow("if (value.$N != null || writer.getSerializeNulls())", param.getCallableName());
                    generateComments(param, code);
                    code.addStatement("writer.name($S)", getSerializedName(param));
                    code.addStatement("if (value.$N == null) writer.nullValue()", param.getCallableName());
                    code.beginControlFlow("else");
                    Adapters.generateWrite(param, spec, code, typeVariables, otherAdapters, message, writeGet);
                    code.endControlFlow();
                    code.endControlFlow();
                }
            }
            for (Property.Getter param : properties.getters) {
                if (param.getType().getKind().isPrimitive()) {
                    generateComments(param, code);
                    code.addStatement("writer.name($S)", getSerializedName(param));
                    Adapters.generateWrite(param, spec, code, typeVariables, otherAdapters, message, () -> code.add("value.$N()", param.getCallableName()));
                } else {
                    code.addStatement("$T $L$N = value.$N()", param.getType(), "$", param.getCallableName(), param.getCallableName());
                    code.beginControlFlow("if ($L$N != null || writer.getSerializeNulls())", "$", param.getCallableName());
                    generateComments(param, code);
                    code.addStatement("writer.name($S)", getSerializedName(param));
                    code.addStatement("if ($L$N == null) writer.nullValue()", "$", param.getCallableName());
                    code.beginControlFlow("else");
                    Adapters.generateWrite(param, spec, code, typeVariables, otherAdapters, message, () -> code.add("$L$N", "$", param.getCallableName()));
                    code.endControlFlow();
                    code.endControlFlow();
                }
            }
            code.addStatement("writer.endObject()");

            spec.addMethod(extension(MethodSpec.methodBuilder("write"), self.getTypeName())
                    .addModifiers(Modifier.PUBLIC, Modifier.STATIC)
                    .addParameter(Cl.GSON_WRITER, "writer")
                    .addException(IOException.class)
                    .addCode(code.build())
                    .build());
        }

        // public static T read(JsonReader reader) throws IOException
        {
            CodeBlock.Builder code = CodeBlock.builder();
            code.beginControlFlow("if (reader.peek() == $T.NULL)", Cl.GSON_TOKEN)
                    .addStatement("reader.nextNull()")
                    .addStatement("return null")
                    .endControlFlow();

            boolean isEmpty = true;
            for (Property<?> param : properties.names) {
                isEmpty = false;
                code.addStatement("$T _$N = $L", param.getType(), param.getName(), TypeHelper.getDefaultValue(param.getType()));
            }
            if (isEmpty) {
                code.addStatement("reader.skipValue()");
            } else {
                code.addStatement("reader.beginObject()")
                        .beginControlFlow("while (reader.hasNext())")
                        .beginControlFlow("switch (reader.nextName())");
                for (Property<?> param : properties.names) {
                    if (param.getType().getKind().isPrimitive()) {
                        code.add("case $S -> _$N = ", getSerializedName(param), param.getName());
                        Adapters.generateRead(param, spec, code, typeVariables, otherAdapters, message);
                        code.add(";\n");
                    } else {
                        code.beginControlFlow("case $S ->", getSerializedName(param))
                                .beginControlFlow("if (reader.peek() == $T.NULL)", Cl.GSON_TOKEN)
                                .addStatement("reader.nextNull()")
                                .addStatement("_$N = null", param.getName());
                        code.unindent().add("} else _$N = ", param.getName());
                        Adapters.generateRead(param, spec, code, typeVariables, otherAdapters, message);
                        code.add(";\n")
                                .endControlFlow();
                    }
                }
                code.add("default -> ")
                        .addStatement("reader.skipValue()");

                code.endControlFlow()
                        .endControlFlow()
                        .addStatement("reader.endObject()");
            }

            code.addStatement("$T result", self.getTypeName());
            ClassName creatorName = ClassName.get((TypeElement) constructionSource.getConstructionElement().getEnclosingElement());
            if (constructionSource instanceof ConstructionSource.Builder builder) {
                StringBuilder args = new StringBuilder();
                for (Property.ConstructorParam param : properties.constructorParams) {
                    args.append(", _").append(param.getName());
                }
                code.add("$T builder = ", builder.getBuilderClass());
                if (constructionSource.isConstructor()) {
                    code.add("new $T($L)", builder.getBuilderClass(), args.length() > 0 ? args.substring(2) : "");
                } else {
                    code.add("$T.$N($L)", creatorName, self.classElement().getSimpleName(), args.length() > 0 ? args.substring(2) : "");
                }
                code.add(";\n");
                for (Property.Setter param : properties.builderParams) {
                    code.addStatement("builder.$N(_$N)", param.getCallableName(), param.getName());
                }
                code.addStatement("result = builder.$N()", builder.getBuildMethod().getSimpleName());
            } else {
                StringBuilder args = new StringBuilder();
                for (Property.Param param : properties.params) {
                    args.append(", _").append(param.getName());
                }
                if (constructionSource.isConstructor()) {
                    code.addStatement("result = new $T($L)", self.getTypeName(), args.length() > 0 ? args.substring(2) : "");
                } else {
                    code.addStatement("result = $T.$N($L)", creatorName, constructionSource.getConstructionElement().getSimpleName(), args.length() > 0 ? args.substring(2) : "");
                }
            }
            for (Property.Setter setter : properties.setters) {
                code.addStatement("result.$N(_$N)", setter.getCallableName(), setter.getName());
            }
            for (Property.Field field : properties.fields) {
                if (Properties.containsName(properties.setters, field)) continue;
                if (Properties.containsName(properties.params, field)) continue;
                code.addStatement("result.$N = _$N", field.getName(), field.getCallableName());
            }
            code.addStatement("return result");

            spec.addMethod(extension(MethodSpec.methodBuilder("read"))
                    .addModifiers(Modifier.PUBLIC, Modifier.STATIC)
                    .returns(self.getTypeName())
                    .addParameter(Cl.GSON_READER, "reader")
                    .addException(IOException.class)
                    .addCode(code.build())
                    .build());
        }
    }
}