/*
 * Copyright (c) 2010 The Broad Institute
 *
 * Permission is hereby granted, free of charge, to any person
 * obtaining a copy of this software and associated documentation
 * files (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use,
 * copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following
 * conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR
 * THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

package org.broadinstitute.sting.commandline;

import org.broadinstitute.sting.utils.exceptions.ReviewedStingException;

import java.lang.reflect.Field;
import java.util.Arrays;
import java.util.List;

/**
 * Describes the source field which defines a command-line argument.
 * A parsed-object version of the command-line argument will be
 * injected into an object containing this field.
 *
 * @author mhanna
 * @version 0.1
 */
public class ArgumentSource {
    /**
     * Field into which to inject command-line arguments.
     */
    public final Field[] parentFields;

    /**
     * Field into which to inject command-line arguments.
     */
    public final Field field;

    /**
     * Type descriptor to use when parsing new argument types.
     */
    private final ArgumentTypeDescriptor typeDescriptor;

    /**
     * Create a new command-line argument target.
     * @param parentFields Parent fields containing the the field.  Field must be annotated with 'ArgumentCollection'.
     * @param field Field containing the argument.  Field must be annotated with 'Input' or 'Output'.
     * @param typeDescriptor custom type descriptor to use when parsing.
     */
    protected ArgumentSource( Field[] parentFields, Field field, ArgumentTypeDescriptor typeDescriptor) {
        this.parentFields = parentFields;
        this.field = field;
        this.typeDescriptor = typeDescriptor;
    }

    /**
     * Somewhat hackish copy constructor to track fields with a custom type descriptor.
     * TODO: Separate type descriptor from ArgumentSource in general usage.
     * @param typeDescriptor New type descriptor for the object.
     */
    public ArgumentSource copyWithCustomTypeDescriptor(final ArgumentTypeDescriptor typeDescriptor) {
        return new ArgumentSource(parentFields,field,typeDescriptor);
    }

    /**
     * True if this argument source equals other.
     * @param other Another object, possibly an argument source, to test for equality.  Any object can
     *              be tested, but only instances of ArgumentSource will result in equals returning true.
     * @return True if this argument source matches other.  False otherwise.
     */
    @Override
    public boolean equals( Object other ) {
        if( other == null )
            return false;
        if( !(other instanceof ArgumentSource) )
            return false;

        ArgumentSource otherArgumentSource = (ArgumentSource)other;
        return this.field == otherArgumentSource.field && Arrays.equals(this.parentFields, otherArgumentSource.parentFields);
    }

    /**
     * Returns an appropriate hash code for this argument source.
     * @return A uniformly distributed hashcode representing this argument source.
     */
    @Override
    public int hashCode() {
        return field.hashCode();
    }

    /**
     * Generate a list of all argument definitions to which this argument source maps.
     * @return A non-null, non-empty list of argument definitions.
     */
    public List<ArgumentDefinition> createArgumentDefinitions() {
        return typeDescriptor.createArgumentDefinitions( this );
    }

    /**
     * Parses the specified value based on the specified type.
     * @param values String representation of all values passed.
     * @return the parsed value of the object.
     */
    public Object parse( ParsingEngine parsingEngine, ArgumentMatches values ) {
        return typeDescriptor.parse( parsingEngine, this, values );
    }

    /**
     * Returns whether this field is required.  Note that flag fields are always forced to 'not required'.
     * @return True if the field is mandatory and not a boolean flag.  False otherwise.
     */
    public boolean isRequired() {
        return (Boolean)CommandLineUtils.getValue(ArgumentTypeDescriptor.getArgumentAnnotation(this),"required");
    }

    /**
     * Returns true if the argument is a flag (a 0-valued argument).
     * @return True if argument is a flag; false otherwise.
     */
    public boolean isFlag() {
        return (field.getType() == Boolean.class) || (field.getType() == Boolean.TYPE);
    }

    /**
     * Can this argument support multiple values, or just one?
     * @return True if the argument supports multiple values.
     */
    public boolean isMultiValued() {
        return typeDescriptor.isMultiValued( this );
    }

    /**
     * Should the given class be hidden from the command-line argument system.
     * @return True if so.  False otherwise.
     */
    public boolean isHidden() {
        return field.isAnnotationPresent(Hidden.class) || field.isAnnotationPresent(Deprecated.class);
    }

    /**
     * Is this command-line argument dependent on some primitive argument types?
     * @return True if this command-line argument depends on other arguments; false otherwise.
     */
    public boolean isDependent() {
        return typeDescriptor instanceof MultiplexArgumentTypeDescriptor;
    }

    /**
     * Returns whether the field has been deprecated and should no longer be used.
     * @return True if field has been deprecated.
     */
    public boolean isDeprecated() {
        return field.isAnnotationPresent(Deprecated.class);
    }

    /**
     * Returns false if a type-specific default can be employed.
     * @return True to throw in a type specific default.  False otherwise.
     */
    public boolean createsTypeDefault() {
        return typeDescriptor.createsTypeDefault(this);
    }

    /**
     * Generates a default for the given type.
     * @param parsingEngine the parsing engine used to validate this argument type descriptor.
     * @return A default value for the given type.
     */
    public Object createTypeDefault(ParsingEngine parsingEngine) {
        return typeDescriptor.createTypeDefault(parsingEngine,this,field.getType());
    }

    /**
     * Builds out a new type descriptor for the given dependent argument as a function
     * of the containing object.
     * @param parsingEngine the parsing engine to use when building out this custom type descriptor.
     * @param containingObject The containing object.
     * @return An argument type descriptor for the custom derivative field.
     */
    public MultiplexArgumentTypeDescriptor createDependentTypeDescriptor(ParsingEngine parsingEngine,Object containingObject) {
        if(!isDependent())
            throw new ReviewedStingException("Field " + field.getName() + " is independent; no dependent type descriptor can be derived.");
        return ((MultiplexArgumentTypeDescriptor)typeDescriptor).createCustomTypeDescriptor(parsingEngine,this,containingObject);
    }

    /**
     * Gets a string representation of the argument source for debugging.
     * @return String representation of the argument source.
     */
    public String toString() {
        return field.getDeclaringClass().getSimpleName() + ": " + field.getName();
    }
}