// -*- mode: c++; c-basic-offset:4 -*-

// This file is part of libdap, A C++ implementation of the OPeNDAP Data

// Access Protocol.

// Copyright (c) 2002,2003 OPeNDAP, Inc.

// Author: James Gallagher <jgallagher@opendap.org>

//

// This library is free software; you can redistribute it and/or

// modify it under the terms of the GNU Lesser General Public

// License as published by the Free Software Foundation; either

// version 2.1 of the License, or (at your option) any later version.

//

// This library is distributed in the hope that it will be useful,

// but WITHOUT ANY WARRANTY; without even the implied warranty of

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

// Lesser General Public License for more details.

//

// You should have received a copy of the GNU Lesser General Public

// License along with this library; if not, write to the Free Software

// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

//

// You can contact OPeNDAP, Inc. at PO Box 112, Saunderstown, RI. 02874-0112.

#include <string>

#include <sstream>

#include <iterator>

//#define DODS_DEBUG

#include "D4CEScanner.h"

#include "D4ConstraintEvaluator.h"

#include "d4_ce_parser.tab.hh"

#include "DMR.h"

#include "D4Group.h"

#include "D4Dimensions.h"

#include "D4Maps.h"

#include "BaseType.h"

#include "Array.h"

#include "Constructor.h"

#include "D4Sequence.h"

#include "D4RValue.h"

#include "D4FilterClause.h"

#include "escaping.h"

#include "parser.h"		// for get_ull()

#include "debug.h"

namespace libdap {

bool D4ConstraintEvaluator::parse(const std::string &expr)

{

	d_expr = expr;	// set for error messages. See the %initial-action section of .yy

	std::istringstream iss(expr);

	D4CEScanner scanner(iss);

	D4CEParser parser(scanner, *this /* driver */);

	if (trace_parsing()) {

		parser.set_debug_level(1);

		parser.set_debug_stream(std::cerr);

	}

	return parser.parse() == 0;

}

void

D4ConstraintEvaluator::throw_not_found(const string &id, const string &ident)

{

    throw Error(no_such_variable, d_expr + ": The variable " + id + " was not found in the dataset (" + ident + ").");

}

void

D4ConstraintEvaluator::throw_not_array(const string &id, const string &ident)

{

	throw Error(no_such_variable, d_expr + ": The variable '" + id + "' is not an Array variable (" + ident + ").");

}

void

D4ConstraintEvaluator::search_for_and_mark_arrays(BaseType *btp)

{

	DBG(cerr << "Entering D4ConstraintEvaluator::search_for_and_mark_arrays...(" << btp->name() << ")" << endl);

	assert(btp->is_constructor_type());

	Constructor *ctor = static_cast<Constructor*>(btp);

	for (Constructor::Vars_iter i = ctor->var_begin(), e = ctor->var_end(); i != e; ++i) {

		switch ((*i)->type()) {

		case dods_array_c:

			DBG(cerr << "Found an array: " << (*i)->name() << endl);

			mark_array_variable(*i);

			break;

		case dods_structure_c:

		case dods_sequence_c:

			DBG(cerr << "Found a ctor: " << (*i)->name() << endl);

			search_for_and_mark_arrays(*i);

			break;

		default:

			break;

		}

	}

}

/**

 * When an identifier is used in a CE, is becomes part of the 'current projection,'

 * which means it is part of the set of variables to be sent back to the client. This

 * method sets a flag in the variable (send_p; pronounced 'send predicate') indicating that.

 *

 * @note This will check if the variable is an array and set it's slices accordingly

 * @param btp BaseType pointer to the variable. Must be non-null

 * @return The BaseType* to the variable; the send_p flag is set as a side effect.

 */

BaseType *

D4ConstraintEvaluator::mark_variable(BaseType *btp)

{

    assert(btp);

    DBG(cerr << "In D4ConstraintEvaluator::mark_variable... (" << btp->name() << "; " << btp->type_name() << ")" << endl);

    btp->set_send_p(true);

    if (btp->type() == dods_array_c ) {

    	mark_array_variable(btp);

    }

    // Test for Constructors and marks arrays they contain

	if (btp->is_constructor_type()) {

		search_for_and_mark_arrays(btp);

	}

	else if (btp->type() == dods_array_c && btp->var() && btp->var()->is_constructor_type()) {

		search_for_and_mark_arrays(btp->var());

	}

    // Now set the parent variables

    BaseType *parent = btp->get_parent();

    while (parent) {

        parent->BaseType::set_send_p(true); // Just set the parent using BaseType's impl.

        parent = parent->get_parent();

    }

    return btp;

}

static bool

array_uses_shared_dimension(Array *map, D4Dimension *source_dim)

{

    for (Array::Dim_iter d = map->dim_begin(), e = map->dim_end(); d != e; ++d) {

        if (source_dim->name() == (*d).name)

            return true;

    }

    return false;

}

/**

 * Add an array to the current projection with slicing. Calling this method will result

 * in the array being returned with anonymous dimensions.

 *

 * @note If btp is an array that has shared dimensions and uses '[]' where a shared dimension

 * is found and if that shared dimension has been sliced, then the slice is used as the array's

 * slice for that dimension (there must be an easier way to explain that...)

 *

 * @param btp

 * @return The BaseType* to the Array variable; the send_p and slicing information is

 * set as a side effect.

 */

// Note: If a Map is not part of the current projection, do not include mention of it

// in the response DMR (CDMR)

BaseType *

D4ConstraintEvaluator::mark_array_variable(BaseType *btp)

{

	assert(btp->type() == dods_array_c);

	Array *a = static_cast<Array*>(btp);

	// If an array appears in a CE without the slicing operators ([]) we still have to

	// call add_constraint(...) for all of it's sdims for them to appear in

	// the Constrained DMR.

	if (d_indexes.empty()) {

	    for (Array::Dim_iter d = a->dim_begin(), de = a->dim_end(); d != de; ++d) {

	        D4Dimension *dim = a->dimension_D4dim(d);

	        if (dim) {

	        	a->add_constraint(d, dim);

	        }

	    }

	}

    else {

        // Test that the indexes and dimensions match in number

        if (d_indexes.size() != a->dimensions())

            throw Error(malformed_expr, "The index constraint for '" + btp->name() + "' does not match its rank.");

        Array::Dim_iter d = a->dim_begin();

        for (vector<index>::iterator i = d_indexes.begin(), e = d_indexes.end(); i != e; ++i) {

            if ((*i).stride > (unsigned long long) (a->dimension_stop(d, false) - a->dimension_start(d, false)) + 1)

                throw Error(malformed_expr, "For '" + btp->name() + "', the index stride value is greater than the number of elements in the Array");

            if (!(*i).rest && ((*i).stop) > (unsigned long long) (a->dimension_stop(d, false) - a->dimension_start(d, false)) + 1)

                throw Error(malformed_expr, "For '" + btp->name() + "', the index stop value is greater than the number of elements in the Array");

            D4Dimension *dim = a->dimension_D4dim(d);

            // In a DAP4 CE, specifying '[]' as an array dimension slice has two meanings.

            // It can mean 'all the elements' of the dimension or 'apply the slicing inherited

            // from the shared dimension'. The latter might be provide 'all the elements'

            // but regardless, the Array object must record the CE correctly.

            if (dim && (*i).empty) {

                // This case corresponds to a CE that uses the '[]' notation for a

                // particular dimension - meaning, use the Shared Dimension size for

                // this dimension's 'slice'.

                a->add_constraint(d, dim);  // calls set_used_by_projected_var(true) + more

            }

            else {

                // This case corresponds to a 'local dimension slice' (See sections 8.6.2 and

                // 8.7 of the spec as of 4/12/16). When a local dimension slice is used, drop

                // the Map(s) that include that dimension. This enables people to constrain

                // an Array when some of the Array's dimensions don't use Shared Dimensions

                // but others do.

                // First apply the constraint to the Array's dimension

                a->add_constraint(d, (*i).start, (*i).stride, (*i).rest ? -1 : (*i).stop);

                // Then, if the Array has Maps, scan those Maps for any that use dimensions

                // that match the name of this particular dimension. If any such Maps are found

                // remove them. This ensure that the Array can be constrained using the  'local

                // dimension slice' without the constrained DMR containing references to Maps

                // that don't exist (or are otherwise nonsensical).

                //

                // This code came about as a fix for problems discovered during testing of

                // local dimension slices. See https://opendap.atlassian.net/browse/HYRAX-98

                // jhrg 4/12/16

                if (!a->maps()->empty()) {

                    for(D4Maps::D4MapsIter m = a->maps()->map_begin(), e = a->maps()->map_end(); m != e; ++m) {

                        if ((*m)->array() == 0)

                            throw Error(malformed_expr, "An array with Maps was found, but one of the Maps was not defined correctly.");

                        Array *map = const_cast<Array*>((*m)->array()); // Array lacks const iterator support

                        // Added a test to ensure 'dim' is not null. This could be the case if

                        // execution gets here and the index *i was not empty. jhrg 4/18/17

                        if (dim && array_uses_shared_dimension(map, dim)) {

                            D4Map *map_to_be_removed = *m;

                            a->maps()->remove_map(map_to_be_removed); // Invalidates the iterator

                            delete map_to_be_removed;   // removed from container; delete

                            break; // must leave the for loop because 'm' is now invalid

                        }

                    }

                }

            }

            ++d;

        }

    }

    d_indexes.clear();  // Clear the info so the next slice expression can be parsed.

	return btp;

}

/**

 * Add an array to the current projection with slicing. Calling this method will result

 * in the array being returned with anonymous dimensions.

 *

 * @param id

 * @return The BaseType* to the Array variable; the send_p and slicing information is

 * set as a side effect.

 */

D4Dimension *

D4ConstraintEvaluator::slice_dimension(const std::string &id, const index &i)

{

    D4Dimension *dim = dmr()->root()->find_dim(id);

    if (i.stride > dim->size())

        throw Error(malformed_expr, "For '" + id + "', the index stride value is greater than the size of the dimension");

    if (!i.rest && (i.stop > dim->size() - 1))

        throw Error(malformed_expr, "For '" + id + "', the index stop value is greater than the size of the dimension");

    dim->set_constraint(i.start, i.stride, i.rest ? dim->size() - 1: i.stop);

    return dim;

}

D4ConstraintEvaluator::index

D4ConstraintEvaluator::make_index(const std::string &i)

{

	unsigned long long v = get_int64(i.c_str());

	return index(v, 1, v, false, false /*empty*/, "");

}

D4ConstraintEvaluator::index

D4ConstraintEvaluator::make_index(const std::string &i, const std::string &s, const std::string &e)

{

	return index(get_int64(i.c_str()), get_int64(s.c_str()), get_int64(e.c_str()), false, false /*empty*/, "");

}

D4ConstraintEvaluator::index

D4ConstraintEvaluator::make_index(const std::string &i, unsigned long long s, const std::string &e)

{

	return index(get_int64(i.c_str()), s, get_int64(e.c_str()), false, false /*empty*/, "");

}

D4ConstraintEvaluator::index

D4ConstraintEvaluator::make_index(const std::string &i, const std::string &s)

{

	return index(get_int64(i.c_str()), get_int64(s.c_str()), 0, true, false /*empty*/, "");

}

D4ConstraintEvaluator::index

D4ConstraintEvaluator::make_index(const std::string &i, unsigned long long s)

{

    return index(get_uint64(i.c_str()), s, 0, true, false /*empty*/, "");

}

static string

expr_msg(const std::string &op, const std::string &arg1, const std::string &arg2)

{

    return "(" + arg1 + " " + op + " " + arg2 + ").";

}

/**

 * @brief Return the D4FilterClause constant for an operator

 *

 * Here are the strings returned by the parser:

 *   GREATER ">"

 *   LESS_EQUAL "<="

 *   GREATER_EQUAL ">="

 *   EQUAL "=="

 *   NOT_EQUAL "!="

 *   REGEX_MATCH "~="

 *

 *   LESS_BBOX "<<"

 *   GREATER_BBOX ">>"

 *

 *   MASK "@="

 *   ND "ND"

 */

static D4FilterClause::ops

get_op_code(const std::string &op)

{

    DBGN(cerr << "Entering " << __PRETTY_FUNCTION__ << endl << "op: " << op << endl);

    if (op == "<")

        return D4FilterClause::less;

    else if (op == ">")

        return D4FilterClause::greater;

    else if (op == "<=")

        return D4FilterClause::less_equal;

    else if (op == ">=")

        return D4FilterClause::greater_equal;

    else if (op == "==")

        return D4FilterClause::equal;

    else if (op == "!=")

        return D4FilterClause::not_equal;

    else if (op == "~=")

        return D4FilterClause::match;

    else

        throw Error(malformed_expr, "The opertator '" + op + "' is not supported.");

}

/**

 * @brief Add a D4FilterClause

 *

 * This method adds a filter clause to the D4Sequence that is on the top of the

 * parser's stack. If there is not a D4Sequence on the stack, an exception is

 * thrown. Similarly, if the filter clause parameters are not valid, then an

 * exception is thrown.

 *

 * Filter clause rules: One of the parameters must be a variable in a D4Sequence

 * and the other must be a constant. The operator must be one of the valid relops.

 * Note that the D4FilterClause objects use the same numerical codes as the DAP2

 * parser/evaluator.

 *

 * @note The parser will have pushed the Sequence onto the BaseType stack during

 * the parse, so variables can be looked up using the top_basetype() (which

 * must be a D4Sequence).

 *

 * @param arg1 The first argument; a D4Sequence variable or a constant.

 * @param arg2 The second argument; a D4Sequence variable or a constant.

 * @param op The infix relop

 */

void

D4ConstraintEvaluator::add_filter_clause(const std::string &op, const std::string &arg1, const std::string &arg2)

{

    DBG(cerr << "Entering: " << __PRETTY_FUNCTION__  << endl);

    // Check that there really is a D4Sequence associated with this filter clause.

    D4Sequence *s = dynamic_cast<D4Sequence*>(top_basetype());

    if (!s)

        throw Error(malformed_expr,

            "When a filter expression is used, it must be bound to a Sequence variable: " + expr_msg(op, arg1, arg2));

    DBG(cerr << "s->name(): " << s->name() << endl);

    // Check that arg1 and 2 are valid

    BaseType *a1 = s->var(arg1);

    BaseType *a2 = s->var(arg2);

    DBG(cerr << "a1: " << a1 << ", a2: " << a2 << endl);

    if (a1 && a2)

        throw Error(malformed_expr,

            "One of the arguments in a filter expression must be a constant: " + expr_msg(op, arg1, arg2));

    if (!(a1 || a2))

        throw Error(malformed_expr,

            "One of the arguments in a filter expression must be a variable in a Sequence: " + expr_msg(op, arg1, arg2));

    // Now we know a1 XOR a2 is true

    if (a1) {

        s->clauses().add_clause(new D4FilterClause(get_op_code(op), new D4RValue(a1), D4RValueFactory(arg2)));

    }

    else {

        s->clauses().add_clause(new D4FilterClause(get_op_code(op), D4RValueFactory(arg1), new D4RValue(a2)));

    }

}

/**

 * @brief If the string has surrounding quotes, remove them.

 *

 * @param src The source string, passed by reference and modified in place

 * @return A reference to the sting parameter.

 */

string &

D4ConstraintEvaluator::remove_quotes(string &s)

{

    if (*s.begin() == '\"' && *(s.end() - 1) == '\"') {

        s.erase(s.begin());

        s.erase(s.end() - 1);

    }

    return s;

}

// This method is called from the parser (see d4_ce_parser.yy, down in the code

// section). This will be called during the call to D4CEParser::parse(), that

// is inside D4ConstraintEvaluator::parse(...)

void

D4ConstraintEvaluator::error(const libdap::location &l, const std::string &m)

{

	ostringstream oss;

	oss << l << ": " << m << ends;

	throw Error(malformed_expr, oss.str());

}

} /* namespace libdap */