import numpy as np
import time
import re

try:
    import h5py
except Exception, e:
    print 'Warning: SimPEG table needs h5py to be installed.'

def natural_keys(text):
    '''
    alist.sort(key=natural_keys) sorts in human order
    http://nedbatchelder.com/blog/200712/human_sorting.html
    (See Toothy's implementation in the comments)
    '''
    atoi = lambda text: int(text) if text.isdigit() else text
    return [ atoi(c) for c in re.split('(\d+)', text) ]


def preIteration(group):
    group.attrs['complete'] = False
    group.attrs['time'] = time.time()

def postIteration(group):
    group.attrs['time'] = time.time() - group.attrs['time']
    group.attrs['date'] = time.ctime()
    group.attrs['complete'] = True

class SimPEGTable:
    """
        This is a wrapper class on the HDF5 file.
    """
    def __init__(self, name, mode='a'):
        if '.hdf5' not in name:
            name += '.hdf5'
        self.f = h5py.File(name,  mode)
        self.root = hdf5Group(self,self.f)

        self.inversions = hdf5InversionGroup(self,self.root.addGroup('inversions',soft=True))

    def show(self): self.root.show()

    def saveInversion(self, invObj, dataPath):

        # Create a new inversion anytime this is run.
        def _startup_hdf5_inv(invObj, m0):
            invObj._invNode = self.inversions.addGroup('%d'%self.inversions.numChildren)
        invObj.hook(_startup_hdf5_inv, overwrite=True)

        # At the start of every iteration we will create a inversion iteration node.
        def _doStartIteration_hdf5_inv(invObj):
            invNodeIt = invObj._invNode.addGroup('%d'%(invObj._iter+1))
            preIteration(invNodeIt)
            invObj._invNodeIt = invNodeIt
        invObj.hook(_doStartIteration_hdf5_inv, overwrite=True)

        def _doEndIteration_hdf5_inv(invObj):
            invObj.save(invObj._invNodeIt)
            postIteration(invObj._invNodeIt)
        invObj.hook(_doEndIteration_hdf5_inv, overwrite=True)

        # Delete all iterates that did not finish.
        def _finish_hdf5_inv(invObj):
            for it in invObj._invNode:
                if not it.attrs['complete']:
                    del self.f[it.path]
            del invObj._invNode
            self.f.flush()
        invObj.hook(_finish_hdf5_inv, overwrite=True)

        def _doStartIteration_hdf5_opt(optObj):
            optNodeIt = optObj.parent._invNode.addGroup('%d.%d'%(optObj.parent._iter, optObj._iter))
            preIteration(optNodeIt)
            optObj._optNodeIt = optNodeIt

        invObj.opt.hook(_doStartIteration_hdf5_opt, overwrite=True)

        def _doEndIteration_hdf5_opt(optObj, xt):
            optObj.save(optObj._optNodeIt)
            postIteration(optObj._optNodeIt)
        invObj.opt.hook(_doEndIteration_hdf5_opt, overwrite=True)




class hdf5Group(object):
    """Has some low level support for wrapping the native HDF5-Group class"""

    def __init__(self, T, groupNode):
        self.T = T
        # check if you are inputing a hdf5Group rather than a raw node, and act accordingly
        if issubclass(groupNode.__class__, hdf5Group):
            self.node = groupNode.node
        else:
            self.node = groupNode

        self.childClass = hdf5Group
        self.parentClass = hdf5Group

    @property
    def children(self):
        """Children names in a list

            Use obj[name] to return the actual node.
        """
        myChildren = [c for c in self.node]
        myChildren.sort(key=natural_keys)
        return myChildren

    @property
    def numChildren(self):
        """Returns the len(children)"""
        return len(self.children)

    @property
    def parent(self):
        """Returns parent node"""
        return self.parentClass(self.T, self.node.parent)

    @property
    def name(self):
        return self.path.split('/')[-1]

    @property
    def path(self):
        """Returns the root path of the group"""
        return self.node.name

    @property
    def attrs(self):
        """Returns a list of attributes in the group"""
        return self.node.attrs

    def addGroup(self, name, soft=False):
        """Adds a child group to the current node."""
        if name in self.children and soft:
            return self[name]
        assert name not in self.children, 'Already a child called: '+self.path+'/'+name
        return self.childClass(self.T, self.node.create_group(name))

    def setArray(self, name, data):
        a = self.node.create_dataset(name, data.shape)
        a[...] = data
        return a

    def __getitem__(self, val):
        if type(val) is int:
            val = self.children[val]
        child = self.node[val]
        if type(child) is h5py.Group:
            child = self.childClass(self.T, child)
        return child

    def __contains__(self, key):
        return key in self.children

    def show(self, pad='', maxDepth=1, depth=0):
        """
            Recursively show the structure of the database.

            For example::

                <hdf5InversionGroup group "/inversions" (1 member)>
                    - <hdf5Inversion group "/inversions/0" (4 members)>
                        - <hdf5InversionIteration group "/inversions/0/0.0" (3 members)>
                        - <hdf5InversionIteration group "/inversions/0/0.1" (3 members)>
                        - <hdf5InversionIteration group "/inversions/0/0.2" (3 members)>
                        - <hdf5InversionIteration group "/inversions/0/0.3" (3 members)>
        """
        s = self.__str__()
        pad += ' '*4
        if maxDepth <= 0: print s
        if depth >= maxDepth: return s

        for c in self.children:
            if issubclass(self[c].__class__, hdf5Group):
                s += '\n%s- %s' % (pad, self[c].show(pad=pad,depth=depth+1,maxDepth=maxDepth))
            else:
                s += '\n%s- %s' % (pad, self[c].__str__())
        if depth is 0:
            print s
        else:
            return s

    def __str__(self):
        return '<%s "%s" (%d member%s)>' % (self.__class__.__name__, self.path, self.numChildren, '' if self.numChildren == 1 else 's')



class hdf5InversionGroup(hdf5Group):
    def __init__(self, T, groupNode):
        hdf5Group.__init__(self, T, groupNode)
        self.childClass = hdf5Inversion


class hdf5Inversion(hdf5Group):
    def __init__(self, T, groupNode):
        hdf5Group.__init__(self, T, groupNode)
        self.parentClass = hdf5InversionGroup
        self.childClass = hdf5InversionIteration


class hdf5InversionIteration(hdf5Group):
    def __init__(self, T, groupNode):
        hdf5Group.__init__(self, T, groupNode)
        self.parentClass = hdf5Inversion