// ==========================================================================
// 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;
using System.Collections;
using System.Reflection;

namespace Python.Runtime {

    /// <summary>
    /// Implements a Python type for managed arrays. This type is essentially
    /// the same as a ClassObject, except that it provides sequence semantics 
    /// to support natural array usage (indexing) from Python.
    /// </summary>

    internal class ArrayObject : ClassBase {

        internal ArrayObject(Type tp) : base(tp) {}

        internal override bool CanSubclass() {
            return false;
        }

        public static IntPtr tp_new(IntPtr tp, IntPtr args, IntPtr kw) {
            ArrayObject self = GetManagedObject(tp) as ArrayObject;
            if (Runtime.PyTuple_Size(args) != 1) {
                return Exceptions.RaiseTypeError("array expects 1 argument");
            }
            IntPtr op = Runtime.PyTuple_GetItem(args, 0);
            Object result;

            if (!Converter.ToManaged(op, self.type, out result, true)) {
                return IntPtr.Zero;
            }
            return CLRObject.GetInstHandle(result, tp);
        }


        //====================================================================
        // Implements __getitem__ for array types.
        //====================================================================

        public static IntPtr mp_subscript(IntPtr ob, IntPtr idx) {
            CLRObject obj = (CLRObject)ManagedType.GetManagedObject(ob);
            Array items = obj.inst as Array;
            Type itemType = obj.inst.GetType().GetElementType();
            int rank = items.Rank;
            int index = 0;
            object value;

            // Note that CLR 1.0 only supports int indexes - methods to
            // support long indices were introduced in 1.1. We could
            // support long indices automatically, but given that long
            // indices are not backward compatible and a relative edge 
            // case, we won't bother for now.

            // Single-dimensional arrays are the most common case and are
            // cheaper to deal with than multi-dimensional, so check first.

            if (rank == 1) {
                index = (int)Runtime.PyInt_AsLong(idx);

                if (Exceptions.ErrorOccurred()) {
                    return Exceptions.RaiseTypeError("invalid index value");
                }

                if (index < 0) {
                    index = items.Length + index;
                }

                try {
                    value = items.GetValue(index);
                }
                catch (IndexOutOfRangeException) {
                    Exceptions.SetError(Exceptions.IndexError,
                                        "array index out of range"
                                        );
                    return IntPtr.Zero; 
                }

                return Converter.ToPython(items.GetValue(index), itemType);
            }

            // Multi-dimensional arrays can be indexed a la: list[1, 2, 3].

            if (!Runtime.PyTuple_Check(idx)) {
                Exceptions.SetError(Exceptions.TypeError,
                                    "invalid index value"
                                    );
                return IntPtr.Zero;
            }

            int count = Runtime.PyTuple_Size(idx);

            Array args = Array.CreateInstance(typeof(Int32), count);

            for (int i = 0; i < count; i++) {
                IntPtr op = Runtime.PyTuple_GetItem(idx, i);
                index = (int)Runtime.PyInt_AsLong(op);

                if (Exceptions.ErrorOccurred()) {
                    return Exceptions.RaiseTypeError("invalid index value");
                }

                if (index < 0) {
                    index = items.GetLength(i) + index;
                }

                args.SetValue(index, i);
            }

            try {
                value = items.GetValue((int[]) args);
            }
            catch (IndexOutOfRangeException) {
                Exceptions.SetError(Exceptions.IndexError,
                                    "array index out of range"
                                    );
                return IntPtr.Zero; 
            }

            return Converter.ToPython(value, itemType);
        }


        //====================================================================
        // Implements __setitem__ for array types.
        //====================================================================

        public static int mp_ass_subscript(IntPtr ob, IntPtr idx, IntPtr v) {
            CLRObject obj = (CLRObject)ManagedType.GetManagedObject(ob);
            Array items = obj.inst as Array;
            Type itemType = obj.inst.GetType().GetElementType();
            int rank = items.Rank;
            int index = 0;
            object value;

            if (items.IsReadOnly) {
                Exceptions.RaiseTypeError("array is read-only");
                return -1;
            }

            if (!Converter.ToManaged(v, itemType, out value, true)) {
                return -1;
            }

            if (rank == 1) {
                index = (int)Runtime.PyInt_AsLong(idx);

                if (Exceptions.ErrorOccurred()) {
                    Exceptions.RaiseTypeError("invalid index value");
                    return -1;
                }

                if (index < 0) {
                    index = items.Length + index;
                }

                try {
                    items.SetValue(value, index);
                }
                catch (IndexOutOfRangeException) {
                    Exceptions.SetError(Exceptions.IndexError,
                                        "array index out of range"
                                        );
                    return -1; 
                }

                return 0;
            }

            if (!Runtime.PyTuple_Check(idx)) {
                Exceptions.RaiseTypeError("invalid index value");
                return -1;
            }

            int count = Runtime.PyTuple_Size(idx);

            Array args = Array.CreateInstance(typeof(Int32), count);

            for (int i = 0; i < count; i++) {
                IntPtr op = Runtime.PyTuple_GetItem(idx, i);
                index = (int)Runtime.PyInt_AsLong(op);

                if (Exceptions.ErrorOccurred()) {
                    Exceptions.RaiseTypeError("invalid index value");
                    return -1;
                }

                if (index < 0) {
                    index = items.GetLength(i) + index;
                }

                args.SetValue(index, i);
            }

            try {
                items.SetValue(value, (int[])args);
            }
            catch (IndexOutOfRangeException) {
                Exceptions.SetError(Exceptions.IndexError,
                                    "array index out of range"
                                    );
                return -1;
            }

            return 0;
        }


        //====================================================================
        // Implements __contains__ for array types.
        //====================================================================

        public static int sq_contains(IntPtr ob, IntPtr v) {
            CLRObject obj = (CLRObject)ManagedType.GetManagedObject(ob);
            Type itemType = obj.inst.GetType().GetElementType();
            IList items = obj.inst as IList;
            object value;

            if (!Converter.ToManaged(v, itemType, out value, false)) {
                return 0;
            }

            if (items.Contains(value)) {
                return 1;
            }

            return 0;
        }


        //====================================================================
        // Implements __len__ for array types.
        //====================================================================

        public static int mp_length(IntPtr ob) {
            CLRObject self = (CLRObject)ManagedType.GetManagedObject(ob);
            Array items = self.inst as Array;
            return items.Length;
        }


    }        

}