# -*- python -*-
# -*- coding: utf-8 -*-
# Started 10/05/2011 by Seblu <seblu@seblu.net>

'''
Image stuff
'''

import os
import stat
import datetime
import time
import json
import hashlib
import StringIO
import ConfigParser
import subprocess
import json
import installsystems.printer as p
import installsystems.tarball as tar
import installsystems.template

image_extension = ".img.tar.bz2"
image_format = "1"

class Image(object):
    '''Abstract class of images'''

    def __init__(self, pbzip2=True):
        self.pbzip2_path = self.path_search("pbzip2") if pbzip2 else None

    def path_search(self, name, path=None):
        '''Search in PATH for a binary'''
        path = path or os.environ["PATH"]
        for d in path.split(os.pathsep):
            if os.path.exists(os.path.join(d, name)):
                return os.path.join(os.path.abspath(d), name)
        return None

    def md5_checksum(self, path):
        '''Compute md5 of a file'''
        m = hashlib.md5()
        m.update(open(path, "r").read())
        return m.hexdigest()

class SourceImage(Image):
    '''Image source manipulation class'''

    def __init__(self, path, verbose=True, create=False, pbzip2=True):
        Image.__init__(self, pbzip2)
        self.base_path = path
        self.parser_path = os.path.join(path, "parser")
        self.setup_path = os.path.join(path, "setup")
        self.data_path = os.path.join(path, "data")
        self.verbose = verbose
        if create:
            self.create()
        self.description = self.parse_description()

    def create(self):
        '''Create an empty source image'''
        # create base directories
        p.arrow("Creating base directories", 1, self.verbose)
        try:
            for d in (self.base_path, self.parser_path, self.setup_path, self.data_path):
                os.mkdir(d)
        except Exception as e:
            raise Exception("Unable to create directory %s: %s" % (d, e))
        # create example files
        p.arrow("Creating examples", 1, self.verbose)
        try:
            # create description example from template
            p.arrow("Creating description example", 2, self.verbose)
            open(os.path.join(self.base_path, "description"), "w").write(
                installsystems.template.description)
            # create parser example from template
            p.arrow("Creating parser script example", 2, self.verbose)
            open(os.path.join(self.parser_path, "01-parser.py"), "w").write(
                installsystems.template.parser)
            # create setup example from template
            p.arrow("Creating setup script example", 2, self.verbose)
            open(os.path.join(self.setup_path, "01-setup.py"), "w").write(
                installsystems.template.setup)
        except Exception as e:
            raise Exception("Unable to example file: %s" % e)
        try:
            # setting rights on files in setup and parser
            p.arrow("Setting executable rights on scripts", 2, self.verbose)
            umask = os.umask(0)
            os.umask(umask)
            for path in (self.parser_path, self.setup_path):
                for f in os.listdir(path):
                    pf = os.path.join(path, f)
                    os.chmod(pf, 0777 & ~umask)
        except Exception as e:
            raise Exception("Unable to set rights on %s: %s" % (pf, e))

    def build(self):
        '''Create packaged image'''
        t0 = time.time()
        # compute script tarball paths
        tarpath = os.path.join(self.base_path,
                               "%s-%s%s" % (self.description["name"],
                                            self.description["version"],
                                            image_extension))
        # check if free to create script tarball
        if os.path.exists(tarpath):
            raise Exception("Tarball already exists. Remove it before")
        # printing pbzip2 status
        if self.pbzip2_path:
            p.arrow("Parallel bzip2 enabled (%s)" % self.pbzip2_path, 1, self.verbose)
        else:
            p.arrow("Parallel bzip disabled", 1, self.verbose)
        #  Create data tarballs
        data_d = self.create_data_tarballs()
        # generate description.json
        jdesc = self.generate_json_description()
        # creating scripts tarball
        p.arrow("Creating scripts tarball", 1, self.verbose)
        p.arrow("Name %s" % os.path.relpath(tarpath), 2, self.verbose)
        try:
            tarball = tar.Tarball.open(tarpath, mode="w:bz2", dereference=True)
        except Exception as e:
            raise Exception("Unable to create tarball %s: %s" % (tarpath, e))
        # add .description.json
        p.arrow("Add .description.json", 2, self.verbose)
        tarball.add_str("description.json", jdesc, tar.tarfile.REGTYPE, 0444)
        # add .format
        p.arrow("Add .format", 2, self.verbose)
        tarball.add_str("format", image_format, tar.tarfile.REGTYPE, 0444)
        # add parser scripts
        p.arrow("Add parser scripts", 2, self.verbose)
        tarball.add(self.parser_path, arcname="parser",
                    recursive=True, filter=self.tar_scripts_filter)
        # add setup scripts
        p.arrow("Add setup scripts", 2, self.verbose)
        tarball.add(self.setup_path, arcname="setup",
                    recursive=True, filter=self.tar_scripts_filter)
        # closing tarball file
        tarball.close()
        # compute building time
        t1 = time.time()
        dt = int(t1 - t0)
        p.arrow("Build time: %s" % datetime.timedelta(seconds=dt), 2, self.verbose)

    def data_tarballs(self):
        '''List all data tarballs in data directory'''
        databalls = dict()
        for dname in os.listdir(self.data_path):
            filename = "%s-%s-%s%s" % (self.description["name"],
                                       self.description["version"],
                                       dname,
                                       image_extension)
            databalls[filename] = os.path.abspath(os.path.join(self.data_path, dname))
        return databalls

    def create_data_tarballs(self):
        '''Create all data tarballs in data directory'''
        p.arrow("Creating data tarballs", 1, self.verbose)
        # build list of data tarball candidate
        candidates = self.data_tarballs()
        if len(candidates) == 0:
            p.arrow("No data tarball", 2, self.verbose)
            return
        # create tarballs
        for candidate in candidates:
            path = os.path.join(self.base_path, candidate)
            if os.path.exists(path):
                p.arrow("Tarball %s already exists." % candidate, 2, self.verbose)
            else:
                p.arrow("Creating tarball %s" % candidate, 2, self.verbose)
                self.create_data_tarball(path, candidates[candidate])

    def create_data_tarball(self, tar_path, data_path):
        '''Create a data tarball'''
        dname = os.path.basename(data_path)
        try:
            # opening file
            if self.pbzip2_path:
                tb = open(tar_path, mode="w")
                p = subprocess.Popen(self.pbzip2_path, shell=False, close_fds=True,
                                     stdin=subprocess.PIPE, stdout=tb.fileno())
                tarball = tar.Tarball.open(mode="w|", dereference=True, fileobj=p.stdin)
            else:
                tarball = tar.Tarball.open(tar_path, "w:bz2", dereference=True)
            tarball.add(data_path, arcname=dname, recursive=True)
            # closing tarball file
            tarball.close()
            if self.pbzip2_path:
                # closing pipe, needed to end pbzip2
                p.stdin.close()
                # waiting pbzip to terminate
                r = p.wait()
                # cleaning openfile
                tb.close()
                # status
                if r != 0:
                    raise Exception("Data tarball %s creation return %s" % (tar_path, r))
        except Exception as e:
            raise Exception("Unable to create data tarball %s: %s" % (tar_path, e))

    def tar_scripts_filter(self, tinfo):
        '''Filter files which can be included in scripts tarball'''
        if not tinfo.name in ("parser", "setup") and os.path.splitext(tinfo.name)[1] != ".py":
            return None
        tinfo.mode = 0555
        tinfo.uid = tinfo.gid = 0
        tinfo.uname = tinfo.gname = "root"
        return tinfo

    def generate_json_description(self):
        '''Generate a json description file'''
        p.arrow("Generating JSON description", 1, self.verbose)
        # copy description
        desc = self.description.copy()
        # timestamp image
        p.arrow("Timestamping", 2, self.verbose)
        desc["date"] = int(time.time())
        # append data tarballs info
        desc["data"] = dict()
        for dt in self.data_tarballs():
            p.arrow("Compute MD5 of %s" % dt, 2, self.verbose)
            path = os.path.join(self.base_path, dt)
            desc["data"][dt] = { "size": os.path.getsize(path),
                                 "md5": self.md5_checksum(path) }
        # create file
        filedesc = StringIO.StringIO()
        # serialize
        return json.dumps(desc)

    def parse_description(self):
        '''Raise an exception is description file is invalid and return vars to include'''
        p.arrow("Parsing description", 1, self.verbose)
        d = dict()
        try:
            descpath = os.path.join(self.base_path, "description")
            cp = ConfigParser.RawConfigParser()
            cp.read(descpath)
            for n in ("name","version", "description", "author"):
                d[n] = cp.get("image", n)
        except Exception as e:
            raise Exception("description: %s" % e)
        return d

class PackageImage(Image):
    '''Packaged image manipulation class'''

    def __init__(self, path, verbose=True):
        Image.__init__(self)
        self.path = os.path.abspath(path)
        self.base_path = os.path.dirname(self.path)
        self.verbose = verbose
        self.parse()

    def parse(self):
        '''Parse tarball and extract metadata'''
        # extract metadata
        p.arrow("Read tarball metadata", 1, self.verbose)
        try:
            tarball = tar.Tarball.open(self.path)
            img_format = tarball.get_str("format")
            img_desc = tarball.get_str("description.json")
            tarball.close()
        except Exception as e:
            raise e
        # check format
        p.arrow("Read format", 2, self.verbose)
        try:
            if img_format != image_format:
                raise Exception()
        except Exception:
            raise Exception("Invalid image format")
        # check description
        p.arrow("Read description", 2, self.verbose)
        try:
            self.description = json.loads(img_desc)
        except Exception as e:
            raise Exception("Invalid description: %s" % e1)

    def check_md5(self):
        '''Check if md5 of data tarballs are correct'''
        p.arrow("Check MD5", 1, self.verbose)
        databalls = self.description["data"]
        for databall in databalls:
            p.arrow(databall, 2, self.verbose)
            md5_meta = databalls[databall]["md5"]
            md5_file = self.md5_checksum(os.path.join(self.base_path, databall))
            if md5_meta != md5_file:
                raise Exception("Invalid md5: %s" % databall)

    def description(self):
        '''Return metadatas of a tarball'''
        return self.description

    def jdescription(self):
        '''Return json formated metadatas'''
        return json.dumps(self.description)

    def name(self):
        '''Return image name'''
        return "%s-%s" % (self.description["name"], self.description["version"])

    def databalls(self):
        '''Create a dict of image and data tarballs'''
        return [ os.path.join(self.base_path, d)
                 for d in self.description["data"] ]

class DataImage(Image):
    '''Data image manipulation class'''

    def __init__(self, path):
        Image.__init__(self)
        self.path = path