package com.fasterxml.jackson.databind;

import java.lang.reflect.Type;
import java.util.Locale;
import java.util.TimeZone;

import com.fasterxml.jackson.annotation.*;

import com.fasterxml.jackson.databind.cfg.HandlerInstantiator;
import com.fasterxml.jackson.databind.cfg.MapperConfig;
import com.fasterxml.jackson.databind.introspect.Annotated;
import com.fasterxml.jackson.databind.introspect.ObjectIdInfo;
import com.fasterxml.jackson.databind.type.TypeFactory;
import com.fasterxml.jackson.databind.util.ClassUtil;
import com.fasterxml.jackson.databind.util.Converter;

/**
 * Shared base class for {@link DeserializationContext} and
 * {@link SerializerProvider}, context objects passed through data-binding
 * process. Designed so that some of implementations can rely on shared
 * aspects like access to secondary contextual objects like type factories
 * or handler instantiators.
 * 
 * @since 2.2
 */
public abstract class DatabindContext
{
    /**
     * Let's limit length of error messages, for cases where underlying data
     * may be very large -- no point in spamming logs with megabytes of meaningless
     * data.
     *
     * @since 2.9
     */
    private final static int MAX_ERROR_STR_LEN = 500;

    /*
    /**********************************************************
    /* Generic config access
    /**********************************************************
     */

    /**
     * Accessor to currently active configuration (both per-request configs
     * and per-mapper config).
     */
    public abstract MapperConfig<?> getConfig();

    /**
     * Convenience method for accessing serialization view in use (if any); equivalent to:
     *<pre>
     *   getConfig().getAnnotationIntrospector();
     *</pre>
     */
    public abstract AnnotationIntrospector getAnnotationIntrospector();

    /*
    /**********************************************************
    /* Access to specific config settings
    /**********************************************************
     */
    
    /**
     * Convenience method for checking whether specified serialization
     * feature is enabled or not.
     * Shortcut for:
     *<pre>
     *  getConfig().isEnabled(feature);
     *</pre>
     */
    public abstract boolean isEnabled(MapperFeature feature);

    /**
     * Convenience method for accessing serialization view in use (if any); equivalent to:
     *<pre>
     *   getConfig().canOverrideAccessModifiers();
     *</pre>
     */
    public abstract boolean canOverrideAccessModifiers();

    /**
     * Accessor for locating currently active view, if any;
     * returns null if no view has been set.
     */
    public abstract Class<?> getActiveView();

    /**
     * @since 2.6
     */
    public abstract Locale getLocale();

    /**
     * @since 2.6
     */
    public abstract TimeZone getTimeZone();

    /**
     * @since 2.7
     */
    public abstract JsonFormat.Value getDefaultPropertyFormat(Class<?> baseType);

    /*
    /**********************************************************
    /* Generic attributes (2.3+)
    /**********************************************************
     */

    /**
     * Method for accessing attributes available in this context.
     * Per-call attributes have highest precedence; attributes set
     * via {@link ObjectReader} or {@link ObjectWriter} have lower
     * precedence.
     * 
     * @param key Key of the attribute to get
     * @return Value of the attribute, if any; null otherwise
     * 
     * @since 2.3
     */
    public abstract Object getAttribute(Object key);

    /**
     * Method for setting per-call value of given attribute.
     * This will override any previously defined value for the
     * attribute within this context.
     * 
     * @param key Key of the attribute to set
     * @param value Value to set attribute to
     * 
     * @return This context object, to allow chaining
     * 
     * @since 2.3
     */
    public abstract DatabindContext setAttribute(Object key, Object value);

    /*
    /**********************************************************
    /* Type instantiation/resolution
    /**********************************************************
     */

    /**
     * Convenience method for constructing {@link JavaType} for given JDK
     * type (usually {@link java.lang.Class})
     */
    public JavaType constructType(Type type) {
        if (type == null) {
            return null;
        }
        return getTypeFactory().constructType(type);
    }

    /**
     * Convenience method for constructing subtypes, retaining generic
     * type parameter (if any)
     */
    public JavaType constructSpecializedType(JavaType baseType, Class<?> subclass) {
        // simple optimization to avoid costly introspection if type-erased type does NOT differ
        if (baseType.getRawClass() == subclass) {
            return baseType;
        }
        return getConfig().constructSpecializedType(baseType, subclass);
    }

    /**
     * Lookup method called when code needs to resolve class name from input;
     * usually simple lookup
     *
     * @since 2.9
     */
    public JavaType resolveSubType(JavaType baseType, String subClass)
        throws JsonMappingException
    {
        // 30-Jan-2010, tatu: Most ids are basic class names; so let's first
        //    check if any generics info is added; and only then ask factory
        //    to do translation when necessary
        if (subClass.indexOf('<') > 0) {
            // note: may want to try combining with specialization (esp for EnumMap)?
            // 17-Aug-2017, tatu: As per [databind#1735] need to ensure assignment
            //    compatibility -- needed later anyway, and not doing so may open
            //    security issues.
            JavaType t = getTypeFactory().constructFromCanonical(subClass);
            if (t.isTypeOrSubTypeOf(baseType.getRawClass())) {
                return t;
            }
        } else {
            Class<?> cls;
            try {
                cls =  getTypeFactory().findClass(subClass);
            } catch (ClassNotFoundException e) { // let caller handle this problem
                return null;
            } catch (Exception e) {
                throw invalidTypeIdException(baseType, subClass, String.format(
                        "problem: (%s) %s",
                        e.getClass().getName(), e.getMessage()));
            }
            if (baseType.isTypeOrSuperTypeOf(cls)) {
                return getTypeFactory().constructSpecializedType(baseType, cls);
            }
        }
        throw invalidTypeIdException(baseType, subClass, "Not a subtype");
    }

    /**
     * Helper method for constructing exception to indicate that given type id
     * could not be resolved to a valid subtype of specified base type.
     * Most commonly called during polymorphic deserialization.
     *<p>
     * Note that most of the time this method should NOT be called directly: instead,
     * method <code>handleUnknownTypeId()</code> should be called which will call this method
     * if necessary.
     *
     * @since 2.9
     */
    protected abstract JsonMappingException invalidTypeIdException(JavaType baseType, String typeId,
            String extraDesc);

    public abstract TypeFactory getTypeFactory();

    /*
    /**********************************************************
    /* Helper object construction
    /**********************************************************
     */

    public ObjectIdGenerator<?> objectIdGeneratorInstance(Annotated annotated,
            ObjectIdInfo objectIdInfo)
        throws JsonMappingException
    {
        Class<?> implClass = objectIdInfo.getGeneratorType();
        final MapperConfig<?> config = getConfig();
        HandlerInstantiator hi = config.getHandlerInstantiator();
        ObjectIdGenerator<?> gen = (hi == null) ? null : hi.objectIdGeneratorInstance(config, annotated, implClass);
        if (gen == null) {
            gen = (ObjectIdGenerator<?>) ClassUtil.createInstance(implClass,
                    config.canOverrideAccessModifiers());
        }
        return gen.forScope(objectIdInfo.getScope());
    }

    public ObjectIdResolver objectIdResolverInstance(Annotated annotated, ObjectIdInfo objectIdInfo)
    {
        Class<? extends ObjectIdResolver> implClass = objectIdInfo.getResolverType();
        final MapperConfig<?> config = getConfig();
        HandlerInstantiator hi = config.getHandlerInstantiator();
        ObjectIdResolver resolver = (hi == null) ? null : hi.resolverIdGeneratorInstance(config, annotated, implClass);
        if (resolver == null) {
            resolver = ClassUtil.createInstance(implClass, config.canOverrideAccessModifiers());
        }

        return resolver;
    }

    /**
     * Helper method to use to construct a {@link Converter}, given a definition
     * that may be either actual converter instance, or Class for instantiating one.
     * 
     * @since 2.2
     */
    @SuppressWarnings("unchecked")
    public Converter<Object,Object> converterInstance(Annotated annotated,
            Object converterDef)
        throws JsonMappingException
    {
        if (converterDef == null) {
            return null;
        }
        if (converterDef instanceof Converter<?,?>) {
            return (Converter<Object,Object>) converterDef;
        }
        if (!(converterDef instanceof Class)) {
            throw new IllegalStateException("AnnotationIntrospector returned Converter definition of type "
                    +converterDef.getClass().getName()+"; expected type Converter or Class<Converter> instead");
        }
        Class<?> converterClass = (Class<?>)converterDef;
        // there are some known "no class" markers to consider too:
        if (converterClass == Converter.None.class || ClassUtil.isBogusClass(converterClass)) {
            return null;
        }
        if (!Converter.class.isAssignableFrom(converterClass)) {
            throw new IllegalStateException("AnnotationIntrospector returned Class "
                    +converterClass.getName()+"; expected Class<Converter>");
        }
        final MapperConfig<?> config = getConfig();
        HandlerInstantiator hi = config.getHandlerInstantiator();
        Converter<?,?> conv = (hi == null) ? null : hi.converterInstance(config, annotated, converterClass);
        if (conv == null) {
            conv = (Converter<?,?>) ClassUtil.createInstance(converterClass,
                    config.canOverrideAccessModifiers());
        }
        return (Converter<Object,Object>) conv;
    }

    /*
    /**********************************************************
    /* Error reporting
    /**********************************************************
     */

    /**
     * Helper method called to indicate a generic problem that stems from type
     * definition(s), not input data, or input/output state; typically this
     * means throwing a {@link com.fasterxml.jackson.databind.exc.InvalidDefinitionException}.
     *
     * @since 2.9
     */
    public abstract <T> T reportBadDefinition(JavaType type, String msg) throws JsonMappingException;

    /**
     * @since 2.9
     */
    public <T> T reportBadDefinition(Class<?> type, String msg) throws JsonMappingException {
        return reportBadDefinition(constructType(type), msg);
    }

    /*
    /**********************************************************
    /* Helper methods
    /**********************************************************
     */

    /**
     * @since 2.9
     */
    protected final String _format(String msg, Object... msgArgs) {
        if (msgArgs.length > 0) {
            return String.format(msg, msgArgs);
        }
        return msg;
    }

    /**
     * @since 2.9
     */
    protected final String _truncate(String desc) {
        if (desc == null) {
            return "";
        }
        if (desc.length() <= MAX_ERROR_STR_LEN) {
            return desc;
        }
        return desc.substring(0, MAX_ERROR_STR_LEN) + "]...[" + desc.substring(desc.length() - MAX_ERROR_STR_LEN);
    }

    /**
     * @since 2.9
     */
    protected String _quotedString(String desc) {
        if (desc == null) {
            return "[N/A]";
        }
        // !!! should we quote it? (in case there are control chars, linefeeds)
        return String.format("\"%s\"", _truncate(desc));
    }
    
    /**
     * @since 2.9
     */
    protected String _colonConcat(String msgBase, String extra) {
        if (extra == null) {
            return msgBase;
        }
        return msgBase + ": " + extra;
    }

    /**
     * @since 2.9
     */
    protected String _desc(String desc) {
        if (desc == null) {
            return "[N/A]";
        }
        // !!! should we quote it? (in case there are control chars, linefeeds)
        return _truncate(desc);
    }
}
