#!/usr/bin/env python

# Copyright (C) 2014 by Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

import sys
import os
import os.path
import argparse
import csv
import collections
import math

try:
    import matplotlib
    matplotlib.use('Agg')
    import matplotlib.font_manager as fm
    import matplotlib.pyplot as plt
except ImportError:
    sys.stderr.write("You need python-matplotlib to generate the size graph\n")
    exit(1)


class Config:
    biggest_first = False
    iec = False
    size_limit = 0.01
    colors = ['#e60004', '#f28e00', '#ffed00', '#940084',
              '#2e1d86', '#0068b5', '#009836', '#97c000']


#
# This function adds a new file to 'filesdict', after checking its
# size. The 'filesdict' contain the relative path of the file as the
# key, and as the value a tuple containing the name of the package to
# which the file belongs and the size of the file.
#
# filesdict: the dict to which  the file is added
# relpath: relative path of the file
# fullpath: absolute path to the file
# pkg: package to which the file belongs
#
def add_file(filesdict, relpath, abspath, pkg):
    if not os.path.exists(abspath):
        return
    if os.path.islink(abspath):
        return
    sz = os.stat(abspath).st_size
    filesdict[relpath] = (pkg, sz)


#
# This function returns a dict where each key is the path of a file in
# the root filesystem, and the value is a tuple containing two
# elements: the name of the package to which this file belongs and the
# size of the file.
#
# builddir: path to the Buildroot output directory
#
def build_package_dict(builddir):
    filesdict = {}
    with open(os.path.join(builddir, "build", "packages-file-list.txt")) as f:
        for l in f.readlines():
            pkg, fpath = l.split(",", 1)
            # remove the initial './' in each file path
            fpath = fpath.strip()[2:]
            fullpath = os.path.join(builddir, "target", fpath)
            add_file(filesdict, fpath, fullpath, pkg)
    return filesdict


#
# This function builds a dictionary that contains the name of a
# package as key, and the size of the files installed by this package
# as the value.
#
# filesdict: dictionary with the name of the files as key, and as
# value a tuple containing the name of the package to which the files
# belongs, and the size of the file. As returned by
# build_package_dict.
#
# builddir: path to the Buildroot output directory
#
def build_package_size(filesdict, builddir):
    pkgsize = collections.defaultdict(int)

    seeninodes = set()
    for root, _, files in os.walk(os.path.join(builddir, "target")):
        for f in files:
            fpath = os.path.join(root, f)
            if os.path.islink(fpath):
                continue

            st = os.stat(fpath)
            if st.st_ino in seeninodes:
                # hard link
                continue
            else:
                seeninodes.add(st.st_ino)

            frelpath = os.path.relpath(fpath, os.path.join(builddir, "target"))
            if frelpath not in filesdict:
                print("WARNING: %s is not part of any package" % frelpath)
                pkg = "unknown"
            else:
                pkg = filesdict[frelpath][0]

            pkgsize[pkg] += st.st_size

    return pkgsize


#
# Given a dict returned by build_package_size(), this function
# generates a pie chart of the size installed by each package.
#
# pkgsize: dictionary with the name of the package as a key, and the
# size as the value, as returned by build_package_size.
#
# outputf: output file for the graph
#
def draw_graph(pkgsize, outputf):
    def size2string(sz):
        if Config.iec:
            divider = 1024.0
            prefixes = ['', 'Ki', 'Mi', 'Gi', 'Ti']
        else:
            divider = 1000.0
            prefixes = ['', 'k', 'M', 'G', 'T']
        while sz > divider and len(prefixes) > 1:
            prefixes = prefixes[1:]
            sz = sz/divider
        # precision is made so that there are always at least three meaningful
        # digits displayed (e.g. '3.14' and '10.4', not just '3' and '10')
        precision = int(2-math.floor(math.log10(sz))) if sz < 1000 else 0
        return '{:.{prec}f} {}B'.format(sz, prefixes[0], prec=precision)

    total = sum(pkgsize.values())
    labels = []
    values = []
    other_value = 0
    unknown_value = 0
    for (p, sz) in sorted(pkgsize.items(), key=lambda x: x[1],
                          reverse=Config.biggest_first):
        if sz < (total * Config.size_limit):
            other_value += sz
        elif p == "unknown":
            unknown_value = sz
        else:
            labels.append("%s (%s)" % (p, size2string(sz)))
            values.append(sz)
    if unknown_value != 0:
        labels.append("Unknown (%s)" % (size2string(unknown_value)))
        values.append(unknown_value)
    if other_value != 0:
        labels.append("Other (%s)" % (size2string(other_value)))
        values.append(other_value)

    plt.figure()
    patches, texts, autotexts = plt.pie(values, labels=labels,
                                        autopct='%1.1f%%', shadow=True,
                                        colors=Config.colors)
    # Reduce text size
    proptease = fm.FontProperties()
    proptease.set_size('xx-small')
    plt.setp(autotexts, fontproperties=proptease)
    plt.setp(texts, fontproperties=proptease)

    plt.suptitle("Filesystem size per package", fontsize=18, y=.97)
    plt.title("Total filesystem size: %s" % (size2string(total)), fontsize=10,
              y=.96)
    plt.savefig(outputf)


#
# Generate a CSV file with statistics about the size of each file, its
# size contribution to the package and to the overall system.
#
# filesdict: dictionary with the name of the files as key, and as
# value a tuple containing the name of the package to which the files
# belongs, and the size of the file. As returned by
# build_package_dict.
#
# pkgsize: dictionary with the name of the package as a key, and the
# size as the value, as returned by build_package_size.
#
# outputf: output CSV file
#
def gen_files_csv(filesdict, pkgsizes, outputf):
    total = 0
    for (p, sz) in pkgsizes.items():
        total += sz
    with open(outputf, 'w') as csvfile:
        wr = csv.writer(csvfile, delimiter=',', quoting=csv.QUOTE_MINIMAL)
        wr.writerow(["File name",
                     "Package name",
                     "File size",
                     "Package size",
                     "File size in package (%)",
                     "File size in system (%)"])
        for f, (pkgname, filesize) in filesdict.items():
            pkgsize = pkgsizes[pkgname]

            if pkgsize == 0:
                percent_pkg = 0
            else:
                percent_pkg = float(filesize) / pkgsize * 100

            percent_total = float(filesize) / total * 100

            wr.writerow([f, pkgname, filesize, pkgsize,
                         "%.1f" % percent_pkg,
                         "%.1f" % percent_total])


#
# Generate a CSV file with statistics about the size of each package,
# and their size contribution to the overall system.
#
# pkgsize: dictionary with the name of the package as a key, and the
# size as the value, as returned by build_package_size.
#
# outputf: output CSV file
#
def gen_packages_csv(pkgsizes, outputf):
    total = sum(pkgsizes.values())
    with open(outputf, 'w') as csvfile:
        wr = csv.writer(csvfile, delimiter=',', quoting=csv.QUOTE_MINIMAL)
        wr.writerow(["Package name", "Package size",
                     "Package size in system (%)"])
        for (pkg, size) in pkgsizes.items():
            wr.writerow([pkg, size, "%.1f" % (float(size) / total * 100)])


#
# Our special action for --iec, --binary, --si, --decimal
#
class PrefixAction(argparse.Action):
    def __init__(self, option_strings, dest, **kwargs):
        for key in ["type", "nargs"]:
            if key in kwargs:
                raise ValueError('"{}" not allowed'.format(key))
        super(PrefixAction, self).__init__(option_strings, dest, nargs=0,
                                           type=bool, **kwargs)

    def __call__(self, parser, namespace, values, option_string=None):
        setattr(namespace, self.dest, option_string in ["--iec", "--binary"])


def main():
    parser = argparse.ArgumentParser(description='Draw size statistics graphs')

    parser.add_argument("--builddir", '-i', metavar="BUILDDIR", required=True,
                        help="Buildroot output directory")
    parser.add_argument("--graph", '-g', metavar="GRAPH",
                        help="Graph output file (.pdf or .png extension)")
    parser.add_argument("--file-size-csv", '-f', metavar="FILE_SIZE_CSV",
                        help="CSV output file with file size statistics")
    parser.add_argument("--package-size-csv", '-p', metavar="PKG_SIZE_CSV",
                        help="CSV output file with package size statistics")
    parser.add_argument("--biggest-first", action='store_true',
                        help="Sort packages in decreasing size order, " +
                             "rather than in increasing size order")
    parser.add_argument("--iec", "--binary", "--si", "--decimal",
                        action=PrefixAction,
                        help="Use IEC (binary, powers of 1024) or SI (decimal, "
                             "powers of 1000, the default) prefixes")
    parser.add_argument("--size-limit", "-l", type=float,
                        help='Under this size ratio, files are accounted to ' +
                             'the generic "Other" package. Default: 0.01 (1%%)')
    args = parser.parse_args()

    Config.biggest_first = args.biggest_first
    Config.iec = args.iec
    if args.size_limit is not None:
        if args.size_limit < 0.0 or args.size_limit > 1.0:
            parser.error("--size-limit must be in [0.0..1.0]")
        Config.size_limit = args.size_limit

    # Find out which package installed what files
    pkgdict = build_package_dict(args.builddir)

    # Collect the size installed by each package
    pkgsize = build_package_size(pkgdict, args.builddir)

    if args.graph:
        draw_graph(pkgsize, args.graph)
    if args.file_size_csv:
        gen_files_csv(pkgdict, pkgsize, args.file_size_csv)
    if args.package_size_csv:
        gen_packages_csv(pkgsize, args.package_size_csv)


if __name__ == "__main__":
    main()