import warnings
try:
    import matplotlib.pyplot as pl
except ImportError:
    warnings.warn("matplotlib could not be loaded!")
    pass
from ._labels import labels
from ..utils import format_value, ordinal_str
from ._utils import convert_ordering, convert_color, merge_nodes, get_sort_order, sort_inds, dendrogram_coords
from . import colors
import numpy as np
import scipy
import copy
from .. import Explanation, Cohorts


# TODO: improve the bar chart to look better like the waterfall plot with numbers inside the bars when they fit
# TODO: Have the Explanation object track enough data so that we can tell (and so show) how many instances are in each cohort
def bar(shap_values, max_display=10, order=Explanation.abs, clustering=None, clustering_cutoff=0.5,
        merge_cohorts=False, show_data="auto", show=True):
    """ Create a bar plot of a set of SHAP values.

    If a single sample is passed then we plot the SHAP values as a bar chart. If an
    Explanation with many samples is passed then we plot the mean absolute value for
    each feature column as a bar chart.


    Parameters
    ----------
    shap_values : shap.Explanation or shap.Cohorts or dictionary of shap.Explanation objects
        A single row of a SHAP Explanation object (i.e. shap_values[0]) or a multi-row Explanation
        object that we want to summarize.

    max_display : int
        The maximum number of bars to display.

    show : bool
        If show is set to False then we don't call the matplotlib.pyplot.show() function. This allows
        further customization of the plot by the caller after the bar() function is finished. 

    """

    # assert str(type(shap_values)).endswith("Explanation'>"), "The shap_values paramemter must be a shap.Explanation object!"

    # convert Explanation objects to dictionaries
    if isinstance(shap_values, Explanation):
        cohorts = {"": shap_values}
    elif isinstance(shap_values, Cohorts):
        cohorts = shap_values.cohorts
    else:
        assert isinstance(shap_values, dict), "You must pass an Explanation object, Cohorts object, or dictionary to bar plot!"

    # unpack our list of Explanation objects we need to plot
    cohort_labels = list(cohorts.keys())
    cohort_exps = list(cohorts.values())
    for i in range(len(cohort_exps)):
        if len(cohort_exps[i].shape) == 2:
            cohort_exps[i] = cohort_exps[i].abs.mean(0)
        assert isinstance(cohort_exps[i], Explanation), "The shap_values paramemter must be a Explanation object, Cohorts object, or dictionary of Explanation objects!"
        assert cohort_exps[i].shape == cohort_exps[0].shape, "When passing several Explanation objects they must all have the same shape!"
        # TODO: check other attributes for equality? like feature names perhaps? probably clustering as well.

    # unpack the Explanation object
    features = cohort_exps[0].data
    feature_names = cohort_exps[0].feature_names
    if clustering is None:
        partition_tree = getattr(cohort_exps[0], "clustering", None)
    elif clustering is False:
        partition_tree = None
    else:
        partition_tree = clustering
    if partition_tree is not None:
        assert partition_tree.shape[1] == 4, "The clustering provided by the Explanation object does not seem to be a partition tree (which is all shap.plots.bar supports)!"
    op_history = cohort_exps[0].op_history
    values = np.array([cohort_exps[i].values for i in range(len(cohort_exps))])

    if len(values[0]) == 0:
        raise Exception("The passed Explanation is empty! (so there is nothing to plot)")

    # we show the data on auto only when there are no transforms
    if show_data == "auto":
        show_data = len(op_history) == 0

    # TODO: Rather than just show the "1st token", "2nd token", etc. it would be better to show the "Instance 0's 1st but", etc
    if issubclass(type(feature_names), str):
        feature_names = [ordinal_str(i)+" "+feature_names for i in range(len(values[0]))]

    # build our auto xlabel based on the transform history of the Explanation object
    xlabel = "SHAP value"
    for op in op_history:
        if op["name"] == "abs":
            xlabel = "|"+xlabel+"|"
        elif op["name"] == "__getitem__":
            pass # no need for slicing to effect our label, it will be used later to find the sizes of cohorts
        else:
            xlabel = str(op["name"])+"("+xlabel+")"

    # find how many instances are in each cohort (if they were created from an Explanation object)
    cohort_sizes = []
    for exp in cohort_exps:
        for op in exp.op_history:
            if op.get("collapsed_instances", False): # see if this if the first op to collapse the instances
                cohort_sizes.append(op["prev_shape"][0])
                break
    

    # unwrap any pandas series
    if str(type(features)) == "<class 'pandas.core.series.Series'>":
        if feature_names is None:
            feature_names = list(features.index)
        features = features.values
    
    # ensure we at least have default feature names
    if feature_names is None:
        feature_names = np.array([labels['FEATURE'] % str(i) for i in range(len(values[0]))])
    
    # determine how many top features we will plot
    if max_display is None:
        max_display = len(feature_names)
    num_features = min(max_display, len(values[0]))
    max_display = min(max_display, num_features)

    # iteratively merge nodes until we can cut off the smallest feature values to stay within
    # num_features without breaking a cluster tree
    orig_inds = [[i] for i in range(len(values[0]))]
    orig_values = values.copy()
    while True:
        feature_order = np.argsort(np.mean([np.argsort(convert_ordering(order, Explanation(values[i]))) for i in range(values.shape[0])], 0))
        if partition_tree is not None:

            # compute the leaf order if we were to show (and so have the ordering respect) the whole partition tree
            clust_order = sort_inds(partition_tree, np.abs(values).mean(0))

            # now relax the requirement to match the parition tree ordering for connections above clustering_cutoff
            dist = scipy.spatial.distance.squareform(scipy.cluster.hierarchy.cophenet(partition_tree))
            feature_order = get_sort_order(dist, clust_order, clustering_cutoff, feature_order)
        
            # if the last feature we can display is connected in a tree the next feature then we can't just cut
            # off the feature ordering, so we need to merge some tree nodes and then try again.
            if max_display < len(feature_order) and dist[feature_order[max_display-1],feature_order[max_display-2]] <= clustering_cutoff:
                #values, partition_tree, orig_inds = merge_nodes(values, partition_tree, orig_inds)
                partition_tree, ind1, ind2 = merge_nodes(np.abs(values).mean(0), partition_tree)
                for i in range(len(values)):
                    values[:,ind1] += values[:,ind2]
                    values = np.delete(values, ind2, 1)
                    orig_inds[ind1] += orig_inds[ind2]
                    del orig_inds[ind2]
            else:
                break
        else:
            break
    
    # here we build our feature names, accounting for the fact that some features might be merged together
    feature_inds = feature_order[:max_display]
    y_pos = np.arange(len(feature_inds), 0, -1)
    feature_names_new = []
    for pos,inds in enumerate(orig_inds):
        if len(inds) == 1:
            feature_names_new.append(feature_names[inds[0]])
        elif len(inds) <= 2:
            feature_names_new.append(" + ".join([feature_names[i] for i in inds]))
        else:
            max_ind = np.argmax(np.abs(orig_values).mean(0)[inds])
            feature_names_new.append(feature_names[inds[max_ind]] + " + %d other features" % (len(inds)-1))
    feature_names = feature_names_new

    # see how many individual (vs. grouped at the end) features we are plotting
    if num_features < len(values[0]):
        num_cut = np.sum([len(orig_inds[feature_order[i]]) for i in range(num_features-1, len(values[0]))])
        values[:,feature_order[num_features-1]] = np.sum([values[:,feature_order[i]] for i in range(num_features-1, len(values[0]))], 0)
    
    # build our y-tick labels
    yticklabels = []
    for i in feature_inds:
        if features is not None and show_data:
            yticklabels.append(format_value(features[i], "%0.03f") + " = " + feature_names[i])
        else:
            yticklabels.append(feature_names[i])
    if num_features < len(values[0]):
        yticklabels[-1] = "Sum of %d other features" % num_cut

    # compute our figure size based on how many features we are showing
    row_height = 0.5
    pl.gcf().set_size_inches(8, num_features * row_height * np.sqrt(len(values)) + 1.5)

    # if negative values are present then we draw a vertical line to mark 0, otherwise the axis does this for us...
    negative_values_present = np.sum(values[:,feature_order[:num_features]] < 0) > 0
    if negative_values_present:
        pl.axvline(0, 0, 1, color="#000000", linestyle="-", linewidth=1, zorder=1)

    # draw the bars
    patterns = (None, '\\\\', '++', 'xx', '////', '*', 'o', 'O', '.', '-')
    total_width = 0.7
    bar_width = total_width / len(values)
    for i in range(len(values)):
        ypos_offset = - ((i - len(values) / 2) * bar_width + bar_width / 2)
        pl.barh(
            y_pos + ypos_offset, values[i,feature_inds],
            bar_width, align='center',
            color=[colors.blue_rgb if values[i,feature_inds[j]] <= 0 else colors.red_rgb for j in range(len(y_pos))],
            hatch=patterns[i], edgecolor=(1,1,1,0.8), label=f"{cohort_labels[i]} [{cohort_sizes[i] if i < len(cohort_sizes) else None}]"
        )

    # draw the yticks (the 1e-8 is so matplotlib 3.3 doesn't try and collapse the ticks)
    pl.yticks(list(y_pos) + list(y_pos + 1e-8), yticklabels + [l.split('=')[-1] for l in yticklabels], fontsize=13)

    xlen = pl.xlim()[1] - pl.xlim()[0]
    fig = pl.gcf()
    ax = pl.gca()
    #xticks = ax.get_xticks()
    bbox = ax.get_window_extent().transformed(fig.dpi_scale_trans.inverted())
    width, height = bbox.width, bbox.height
    bbox_to_xscale = xlen/width

    for i in range(len(values)):
        ypos_offset = - ((i - len(values) / 2) * bar_width + bar_width / 2)
        for j in range(len(y_pos)):
            ind = feature_order[j]
            if values[i,ind] < 0:
                pl.text(
                    values[i,ind] - (5/72)*bbox_to_xscale, y_pos[j] + ypos_offset, format_value(values[i,ind], '%+0.02f'),
                    horizontalalignment='right', verticalalignment='center', color=colors.blue_rgb,
                    fontsize=12
                )
            else:
                pl.text(
                    values[i,ind] + (5/72)*bbox_to_xscale, y_pos[j] + ypos_offset, format_value(values[i,ind], '%+0.02f'),
                    horizontalalignment='left', verticalalignment='center', color=colors.red_rgb,
                    fontsize=12
                )

    # put horizontal lines for each feature row
    for i in range(num_features):
        pl.axhline(i+1, color="#888888", lw=0.5, dashes=(1, 5), zorder=-1)
    
    if features is not None:
        features = list(features)

        # try and round off any trailing zeros after the decimal point in the feature values
        for i in range(len(features)):
            try:
                if round(features[i]) == features[i]:
                    features[i] = int(features[i])
            except:
                pass # features[i] must not be a number
    
    pl.gca().xaxis.set_ticks_position('bottom')
    pl.gca().yaxis.set_ticks_position('none')
    pl.gca().spines['right'].set_visible(False)
    pl.gca().spines['top'].set_visible(False)
    if negative_values_present:
        pl.gca().spines['left'].set_visible(False)
    pl.gca().tick_params('x', labelsize=11)

    xmin,xmax = pl.gca().get_xlim()
    ymin,ymax = pl.gca().get_ylim()
    
    if negative_values_present:
        pl.gca().set_xlim(xmin - (xmax-xmin)*0.05, xmax + (xmax-xmin)*0.05)
    else:
        pl.gca().set_xlim(xmin, xmax + (xmax-xmin)*0.05)
    
    # if features is None:
    #     pl.xlabel(labels["GLOBAL_VALUE"], fontsize=13)
    # else:
    pl.xlabel(xlabel, fontsize=13)

    if len(values) > 1:
        pl.legend(fontsize=12)

    # color the y tick labels that have the feature values as gray
    # (these fall behind the black ones with just the feature name)
    tick_labels = pl.gca().yaxis.get_majorticklabels()
    for i in range(num_features):
        tick_labels[i].set_color("#999999")

    # draw a dendrogram if we are given a partition tree
    if partition_tree is not None:
        
        # compute the dendrogram line positions based on our current feature order
        feature_pos = np.argsort(feature_order)
        ylines,xlines = dendrogram_coords(feature_pos, partition_tree)
        
        # plot the distance cut line above which we don't show tree edges
        xmin,xmax = pl.xlim()
        xlines_min,xlines_max = np.min(xlines),np.max(xlines)
        ct_line_pos = (clustering_cutoff / (xlines_max - xlines_min)) * 0.1 * (xmax - xmin) + xmax
        pl.text(
            ct_line_pos + 0.005 * (xmax - xmin), (ymax - ymin)/2, "Clustering cutoff = " + format_value(clustering_cutoff, '%0.02f'),
            horizontalalignment='left', verticalalignment='center', color="#999999",
            fontsize=12, rotation=-90
        )
        l = pl.axvline(ct_line_pos, color="#dddddd", dashes=(1, 1))
        l.set_clip_on(False)
        
        for (xline, yline) in zip(xlines, ylines):
            
            # normalize the x values to fall between 0 and 1
            xv = (np.array(xline) / (xlines_max - xlines_min))

            # only draw if we are not going past distance threshold
            if np.array(xline).max() <= clustering_cutoff:

                # only draw if we are not going past the bottom of the plot
                if yline.max() < max_display:
                    l = pl.plot(
                        xv * 0.1 * (xmax - xmin) + xmax,
                        max_display - np.array(yline),
                        color="#999999"
                    )
                    for v in l:
                        v.set_clip_on(False)
    
    if show:
        pl.show()



# def compute_sort_counts(partition_tree, leaf_values, pos=None):
#     if pos is None:
#         pos = partition_tree.shape[0]-1
    
#     M = partition_tree.shape[0] + 1
        
#     if pos < 0:
#         return 1,leaf_values[pos + M]
    
#     left = int(partition_tree[pos, 0]) - M
#     right = int(partition_tree[pos, 1]) - M
    
#     left_val,left_sum = compute_sort_counts(partition_tree, leaf_values, left)
#     right_val,right_sum = compute_sort_counts(partition_tree, leaf_values, right)
    
#     if left_sum > right_sum:
#         left_val = right_val + 1
#     else:
#         right_val = left_val + 1

#     if left >= 0:
#         partition_tree[left,3] = left_val
#     if right >= 0:
#         partition_tree[right,3] = right_val

    
#     return max(left_val, right_val) + 1, max(left_sum, right_sum)

def bar_legacy(shap_values, features=None, feature_names=None, max_display=None, show=True):
    
    # unwrap pandas series
    if str(type(features)) == "<class 'pandas.core.series.Series'>":
        if feature_names is None:
            feature_names = list(features.index)
        features = features.values
        
    if feature_names is None:
        feature_names = np.array([labels['FEATURE'] % str(i) for i in range(len(shap_values))])
    
    if max_display is None:
        max_display = 7
    else:
        max_display = min(len(feature_names), max_display)
        
    
    feature_order = np.argsort(-np.abs(shap_values))
    
    # 
    feature_inds = feature_order[:max_display]
    y_pos = np.arange(len(feature_inds), 0, -1)
    pl.barh(
        y_pos, shap_values[feature_inds],
        0.7, align='center',
        color=[colors.red_rgb if shap_values[feature_inds[i]] > 0 else colors.blue_rgb for i in range(len(y_pos))]
    )
    pl.yticks(y_pos, fontsize=13)
    if features is not None:
        features = list(features)

        # try and round off any trailing zeros after the decimal point in the feature values
        for i in range(len(features)):
            try:
                if round(features[i]) == features[i]:
                    features[i] = int(features[i])
            except TypeError:
                pass # features[i] must not be a number
    yticklabels = []
    for i in feature_inds:
        if features is not None:
            yticklabels.append(feature_names[i] + " = " + str(features[i]))
        else:
            yticklabels.append(feature_names[i])
    pl.gca().set_yticklabels(yticklabels)
    pl.gca().xaxis.set_ticks_position('bottom')
    pl.gca().yaxis.set_ticks_position('none')
    pl.gca().spines['right'].set_visible(False)
    pl.gca().spines['top'].set_visible(False)
    #pl.gca().spines['left'].set_visible(False)
    
    pl.xlabel("SHAP value (impact on model output)")
    
    if show:
        pl.show()