package io.trygvis.persistence.generators;

import io.trygvis.container.compiler.SqlUnitModel;
import io.trygvis.container.compiler.model.AnnotationG;
import io.trygvis.container.compiler.model.ClassG;
import io.trygvis.container.compiler.model.Constructor;
import io.trygvis.container.compiler.model.FieldRef;
import io.trygvis.container.compiler.model.Imports;
import io.trygvis.container.compiler.model.MethodRef;
import io.trygvis.container.compiler.model.Parameters;
import io.trygvis.container.compiler.model.TypeRef;
import io.trygvis.persistence.EntityMirror;
import io.trygvis.persistence.sql.SqlDao;
import io.trygvis.persistence.sql.SqlEntityManager;
import io.trygvis.persistence.sql.SqlEntityManagerFactory;

import java.io.IOException;
import java.sql.Connection;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import static io.trygvis.container.compiler.Utils.toClassName;
import static io.trygvis.container.compiler.Utils.toFieldName;
import static io.trygvis.container.compiler.model.Parameters.ParameterRef;
import static java.lang.reflect.Modifier.PUBLIC;

public class EntityManagerGenerator {
    public static ClassG generateEntityManager(SqlUnitModel unit) throws IOException {
        String prefix = unit.getPackageName() + "." + toClassName(unit.getName());
        TypeRef emType = new TypeRef(prefix + "EntityManager");

        ClassG g = new ClassG(PUBLIC, emType).
                extendsType(SqlEntityManager.class);

        Map<EntityMirror, FieldRef> daoFields = new HashMap<>();
        for (EntityMirror entity : unit.getEntities().values()) {
            daoFields.put(entity, g.addField(entity.daoType, toFieldName(entity.type.className)));
        }

        g.add(constructor(unit, g.imports, daoFields));
        g.add(getSqlDao(unit, g.imports, daoFields));

        return g;
    }

    private static Constructor constructor(SqlUnitModel unit, Imports imports, Map<EntityMirror, FieldRef> daoFields) {
        Parameters p = new Parameters();
        ParameterRef semf = p.addParameter(imports.add(SqlEntityManagerFactory.class), "emf");
        ParameterRef c = p.addParameter(imports.add(Connection.class), "c");
        List<String> body = new ArrayList<>();
        body.add("super(" + semf.name + ", " + c.name + ");");

        for (EntityMirror entity : unit.getEntities().values()) {
            FieldRef f = daoFields.get(entity);
            body.add("this." + f.name + " = new " + entity.daoType.plainName + "(" + c.name + ");");
        }
        return new Constructor(p, body);
    }

    public static MethodRef getSqlDao(SqlUnitModel unit, Imports imports, Map<EntityMirror, FieldRef> daoFields) {
        TypeRef sqlDatoType = imports.add(new TypeRef(SqlDao.class)).args("Id", "T");
        Parameters p = new Parameters();
        TypeRef klassType = new TypeRef(Class.class).args("T");
        ParameterRef klass = p.addParameter(klassType, "klass");
        List<String> body = new ArrayList<>();
        for (EntityMirror entity : unit.getEntities().values()) {
            body.add("if (klass == " + entity.type.plainName + ".class) {");
            body.add("    return (SqlDao<Id, T>) " + daoFields.get(entity).name + ";");
            body.add("}");
        }
        body.add("throw new RuntimeException(\"Type is not a part of this persistence unit: \" + klass);");
        return new MethodRef(PUBLIC, sqlDatoType, "getDao", p, body).typeArgs("Id", "T").
                annotation(new AnnotationG(new TypeRef(SuppressWarnings.class), "\"unchecked\""));
    }

    /*
    public static ClassG sem(EntityMirror entity) {
        ClassG g = new ClassG(PUBLIC, new TypeRef(entity.type.className + "SEM"));
        g.implementsType(g.imports.add(new TypeRef(SqlDao.class)).args(entity.idType, entity.type));
        return g.
                add(semFind(entity, g.imports)).
                add(semPersist(entity, g.imports)).
                add(semMerge(entity, g.imports)).
                add(semRemove(entity, g.imports));
    }

    public static MethodRef semFind(EntityMirror entity, Imports imports) {
        TypeRef type = imports.add(entity.type);
        TypeRef sqlException = imports.add(SQLException.class);
        Parameters p = new Parameters();
        ParameterRef primaryKey = p.addParameter(new TypeRef(Object.class), "primaryKey");
        List<String> body = new ArrayList<>();
        body.add("throw new " + sqlException.plainName + "(\"Not implemented\");");
        return new MethodRef(PUBLIC, type, "find", p, tryCatchSqlException(imports, body));
    }

    public static MethodRef semPersist(EntityMirror entity, Imports imports) {
        TypeRef type = imports.add(entity.type);
        TypeRef dao = imports.add(entity.daoType);
        Parameters p = new Parameters();
        ParameterRef e = p.addParameter(type, "entity");
        List<String> body = new ArrayList<>();
        body.add(dao.plainName + ".insertInto(currentConnection(), " + e.name + ");");
        return new MethodRef(PUBLIC, VOID, "persist", p, tryCatchSqlException(imports, body));
    }

    public static MethodRef semMerge(EntityMirror entity, Imports imports) {
        TypeRef type = imports.add(entity.type);
        TypeRef sqlException = imports.add(SQLException.class);
        Parameters p = new Parameters();
        ParameterRef e = p.addParameter(type, "entity");
        List<String> body = new ArrayList<>();
        body.add("throw new " + sqlException.plainName + "(\"Not implemented\");");
        return new MethodRef(PUBLIC, type, "merge", p, tryCatchSqlException(imports, body));
    }

    public static MethodRef semRemove(EntityMirror entity, Imports imports) {
        TypeRef type = imports.add(entity.type);
        TypeRef sqlException = imports.add(SQLException.class);
        Parameters p = new Parameters();
        ParameterRef e = p.addParameter(type, "entity");
        List<String> body = new ArrayList<>();
        body.add("throw new " + sqlException.plainName + "(\"Not implemented\");");
        return new MethodRef(PUBLIC, VOID, "remove", p, tryCatchSqlException(imports, body));
    }
    */
}