"""Backward compatible with arrayfns from Numeric.

"""
from __future__ import division, absolute_import, print_function

__all__ = ['array_set', 'construct3', 'digitize', 'error', 'find_mask',
           'histogram', 'index_sort', 'interp', 'nz', 'reverse', 'span',
           'to_corners', 'zmin_zmax']

import numpy as np
from numpy import asarray

class error(Exception):
    pass

def array_set(vals1, indices, vals2):
    indices = asarray(indices)
    if indices.ndim != 1:
        raise ValueError("index array must be 1-d")
    if not isinstance(vals1, np.ndarray):
        raise TypeError("vals1 must be an ndarray")
    vals1 = asarray(vals1)
    vals2 = asarray(vals2)
    if vals1.ndim != vals2.ndim or vals1.ndim < 1:
        raise error("vals1 and vals2 must have same number of dimensions (>=1)")
    vals1[indices] = vals2

from numpy import digitize
from numpy import bincount as histogram

def index_sort(arr):
    return asarray(arr).argsort(kind='heap')

def interp(y, x, z, typ=None):
    """y(z) interpolated by treating y(x) as piecewise function
    """
    res = np.interp(z, x, y)
    if typ is None or typ == 'd':
        return res
    if typ == 'f':
        return res.astype('f')

    raise error("incompatible typecode")

def nz(x):
    x = asarray(x, dtype=np.ubyte)
    if x.ndim != 1:
        raise TypeError("intput must have 1 dimension.")
    indxs = np.flatnonzero(x != 0)
    return indxs[-1].item()+1

def reverse(x, n):
    x = asarray(x, dtype='d')
    if x.ndim != 2:
        raise ValueError("input must be 2-d")
    y = np.empty_like(x)
    if n == 0:
        y[...] = x[::-1,:]
    elif n == 1:
        y[...] = x[:, ::-1]
    return y

def span(lo, hi, num, d2=0):
    x = np.linspace(lo, hi, num)
    if d2 <= 0:
        return x
    else:
        ret = np.empty((d2, num), x.dtype)
        ret[...] = x
        return ret

def zmin_zmax(z, ireg):
    z = asarray(z, dtype=float)
    ireg = asarray(ireg, dtype=int)
    if z.shape != ireg.shape or z.ndim != 2:
        raise ValueError("z and ireg must be the same shape and 2-d")
    ix, iy = np.nonzero(ireg)
    # Now, add more indices
    x1m = ix - 1
    y1m = iy-1
    i1 = x1m>=0
    i2 = y1m>=0
    i3 = i1 & i2
    nix = np.r_[ix, x1m[i1], x1m[i1], ix[i2] ]
    niy = np.r_[iy, iy[i1],  y1m[i3], y1m[i2]]
    # remove any negative indices
    zres = z[nix, niy]
    return zres.min().item(), zres.max().item()


def find_mask(fs, node_edges):
    raise NotImplementedError

def to_corners(arr, nv, nvsum):
    raise NotImplementedError


def construct3(mask, itype):
    raise NotImplementedError