"""Implementation of the deep stats class."""

import math

from allmydata.interfaces import IImmutableFileNode
from allmydata.interfaces import IMutableFileNode
from allmydata.interfaces import IDirectoryNode
from allmydata.unknown import UnknownNode
from allmydata.uri import LiteralFileURI
from allmydata.uri import from_string
from allmydata.util import mathutil

class DeepStats(object):
    """Deep stats object.

    Holds results of the deep-stats opetation.
    Used for json generation in the API."""

    def __init__(self, origin):
        self.origin = origin
        self.stats = {}
        for k in ["count-immutable-files",
                  "count-mutable-files",
                  "count-literal-files",
                  "count-files",
                  "count-directories",
                  "count-unknown",
                  "size-immutable-files",
                  #"size-mutable-files",
                  "size-literal-files",
                  "size-directories",
                  "largest-directory",
                  "largest-directory-children",
                  "largest-immutable-file",
                  #"largest-mutable-file",
                 ]:
            self.stats[k] = 0
        self.histograms = {}
        for k in ["size-files-histogram"]:
            self.histograms[k] = {} # maps (min,max) to count
        self.buckets = [(0,0), (1,3)]
        self.root = math.sqrt(10)

    def set_monitor(self, monitor):
        self.monitor = monitor
        monitor.origin_si = self.origin.get_storage_index()
        monitor.set_status(self.get_results())

    def add_node(self, node, childpath):
        if isinstance(node, UnknownNode):
            self.add("count-unknown")
        elif IDirectoryNode.providedBy(node):
            self.add("count-directories")
        elif IMutableFileNode.providedBy(node):
            self.add("count-files")
            self.add("count-mutable-files")
            # TODO: update the servermap, compute a size, add it to
            # size-mutable-files, max it into "largest-mutable-file"
        elif IImmutableFileNode.providedBy(node): # CHK and LIT
            self.add("count-files")
            size = node.get_size()
            self.histogram("size-files-histogram", size)
            theuri = from_string(node.get_uri())
            if isinstance(theuri, LiteralFileURI):
                self.add("count-literal-files")
                self.add("size-literal-files", size)
            else:
                self.add("count-immutable-files")
                self.add("size-immutable-files", size)
                self.max("largest-immutable-file", size)

    def enter_directory(self, parent, children):
        dirsize_bytes = parent.get_size()
        if dirsize_bytes is not None:
            self.add("size-directories", dirsize_bytes)
            self.max("largest-directory", dirsize_bytes)
        dirsize_children = len(children)
        self.max("largest-directory-children", dirsize_children)

    def add(self, key, value=1):
        self.stats[key] += value

    def max(self, key, value):
        self.stats[key] = max(self.stats[key], value)

    def which_bucket(self, size):
        # return (min,max) such that min <= size <= max
        # values are from the set (0,0), (1,3), (4,10), (11,31), (32,100),
        # (101,316), (317, 1000), etc: two per decade
        assert size >= 0
        i = 0
        while True:
            if i >= len(self.buckets):
                # extend the list
                new_lower = self.buckets[i-1][1]+1
                new_upper = int(mathutil.next_power_of_k(new_lower, self.root))
                self.buckets.append((new_lower, new_upper))
            maybe = self.buckets[i]
            if maybe[0] <= size <= maybe[1]:
                return maybe
            i += 1

    def histogram(self, key, size):
        bucket = self.which_bucket(size)
        h = self.histograms[key]
        if bucket not in h:
            h[bucket] = 0
        h[bucket] += 1

    def get_results(self):
        stats = self.stats.copy()
        for key in self.histograms:
            h = self.histograms[key]
            out = [ (bucket[0], bucket[1], h[bucket]) for bucket in h ]
            out.sort()
            stats[key] = out
        return stats

    def finish(self):
        return self.get_results()