// ==========================================================================
// This software is subject to the provisions of the Zope Public License,
// Version 2.0 (ZPL).  A copy of the ZPL should accompany this distribution.
// THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
// WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
// WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
// FOR A PARTICULAR PURPOSE.
// ==========================================================================

using System;

namespace Python.Runtime {

    /// <summary>
    /// Represents a Python tuple object. See the documentation at
    /// http://www.python.org/doc/current/api/tupleObjects.html for details.
    /// </summary>

    public class PyTuple : PySequence {

        /// <summary>
        /// PyTuple Constructor
        /// </summary>
        ///
        /// <remarks>
        /// Creates a new PyTuple from an existing object reference. Note 
        /// that the instance assumes ownership of the object reference. 
        /// The object reference is not checked for type-correctness. 
        /// </remarks>

        public PyTuple(IntPtr ptr) : base(ptr) {}


        /// <summary>
        /// PyTuple Constructor
        /// </summary>
        ///
        /// <remarks>
        /// Copy constructor - obtain a PyTuple from a generic PyObject. An 
        /// ArgumentException will be thrown if the given object is not a
        /// Python tuple object.
        /// </remarks>

        public PyTuple(PyObject o) : base() {
            if (!IsTupleType(o)) {
                throw new ArgumentException("object is not a tuple");
            }
            Runtime.Incref(o.obj);
            obj = o.obj;
        }


        /// <summary>
        /// PyTuple Constructor
        /// </summary>
        ///
        /// <remarks>
        /// Creates a new empty PyTuple.
        /// </remarks>

        public PyTuple() : base() {
            obj = Runtime.PyTuple_New(0);
            if (obj == IntPtr.Zero) {
                throw new PythonException();
            }
        }
        

        /// <summary>
        /// PyTuple Constructor
        /// </summary>
        ///
        /// <remarks>
        /// Creates a new PyTuple from an array of PyObject instances.
        /// </remarks>

        public PyTuple(PyObject[] items) : base() {
            int count = items.Length;
            obj = Runtime.PyTuple_New(count);
            for (int i = 0; i < count; i++) {
                IntPtr ptr = items[i].obj;
                Runtime.Incref(ptr);
                int r = Runtime.PyTuple_SetItem(obj, i, ptr);
                if (r < 0) {
                    throw new PythonException();
                }
            }
        }


        /// <summary>
        /// IsTupleType Method
        /// </summary>
        ///
        /// <remarks>
        /// Returns true if the given object is a Python tuple.
        /// </remarks>

        public static bool IsTupleType(PyObject value) {
            return Runtime.PyTuple_Check(value.obj);
        }


        /// <summary>
        /// AsTuple Method
        /// </summary>
        ///
        /// <remarks>
        /// Convert a Python object to a Python tuple if possible, raising  
        /// a PythonException if the conversion is not possible. This is
        /// equivalent to the Python expression "tuple(object)".
        /// </remarks>

        public static PyTuple AsTuple(PyObject value) {
            IntPtr op = Runtime.PySequence_Tuple(value.obj);
            if (op == IntPtr.Zero) {
                throw new PythonException();
            }
            return new PyTuple(op);
        }


    }


}