#include "ruby_libxml.h"
#include "ruby_xml_schema.h"

/*
 * Document-class: LibXML::XML::Schema
 *
 * The XML::Schema class is used to prepare XML Schemas for validation of xml
 * documents.
 *
 * Schemas can be created from XML documents, strings or URIs using the
 * corresponding methods (new for URIs).
 *
 * Once a schema is prepared, an XML document can be validated by the
 * XML::Document#validate_schema method providing the XML::Schema object
 * as parameter. The method return true if the document validates, false
 * otherwise.
 *
 * Basic usage:
 *
 *  # parse schema as xml document
 *  schema_document = XML::Document.file('schema.rng')
 *
 *  # prepare schema for validation
 *  schema = XML::Schema.document(schema_document)
 *
 *  # parse xml document to be validated
 *  instance = XML::Document.file('instance.xml')
 *
 *  # validate
 *  instance.validate_schema(schema)
 */

VALUE cXMLSchema;

static void rxml_schema_free(xmlSchemaPtr xschema)
{
  xmlSchemaFree(xschema);
}

/*
 * call-seq:
 *    XML::Schema.initialize(schema_uri) -> schema
 *
 * Create a new schema from the specified URI.
 */
static VALUE rxml_schema_init_from_uri(VALUE class, VALUE uri)
{
  xmlSchemaParserCtxtPtr xparser;
  xmlSchemaPtr xschema;

  Check_Type(uri, T_STRING);

  xparser = xmlSchemaNewParserCtxt(StringValuePtr(uri));
  xschema = xmlSchemaParse(xparser);
  xmlSchemaFreeParserCtxt(xparser);

  return Data_Wrap_Struct(cXMLSchema, NULL, rxml_schema_free, xschema);
}

/*
 * call-seq:
 *    XML::Schema.document(document) -> schema
 *
 * Create a new schema from the specified document.
 */
static VALUE rxml_schema_init_from_document(VALUE class, VALUE document)
{
  xmlDocPtr xdoc;
  xmlSchemaPtr xschema;
  xmlSchemaParserCtxtPtr xparser;

  Data_Get_Struct(document, xmlDoc, xdoc);

  xparser = xmlSchemaNewDocParserCtxt(xdoc);
  xschema = xmlSchemaParse(xparser);
  xmlSchemaFreeParserCtxt(xparser);

  return Data_Wrap_Struct(cXMLSchema, NULL, rxml_schema_free, xschema);
}

/*
 * call-seq:
 *    XML::Schema.string("schema_data") -> "value"
 *
 * Create a new schema using the specified string.
 */
static VALUE rxml_schema_init_from_string(VALUE self, VALUE schema_str)
{
  xmlSchemaParserCtxtPtr xparser;
  xmlSchemaPtr xschema;

  Check_Type(schema_str, T_STRING);

  xparser = xmlSchemaNewMemParserCtxt(StringValuePtr(schema_str), strlen(
      StringValuePtr(schema_str)));
  xschema = xmlSchemaParse(xparser);
  xmlSchemaFreeParserCtxt(xparser);

  return Data_Wrap_Struct(cXMLSchema, NULL, rxml_schema_free, xschema);
}

void rxml_init_schema(void)
{
  cXMLSchema = rb_define_class_under(mXML, "Schema", rb_cObject);
  rb_define_singleton_method(cXMLSchema, "new", rxml_schema_init_from_uri, 1);
  rb_define_singleton_method(cXMLSchema, "from_string", rxml_schema_init_from_string, 1);
  rb_define_singleton_method(cXMLSchema, "document", rxml_schema_init_from_document, 1);
}