#-*- coding: utf-8 -*-
# rpm.py
# Base RPM package manager class
#
# Copyright (C) 2016 Jakub Kadlcik
#
# This copyrighted material is made available to anyone wishing to use,
# modify, copy, or redistribute it subject to the terms and conditions of
# the GNU General Public License v.2, or (at your option) any later version.
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY expressed or implied, including the implied warranties 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., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301, USA.
#

from __future__ import absolute_import


from tracer.resources.system import System
if System.distribution() in ["fedora", "rhel", "centos", "mageia", "ol"]:

	from os import listdir
	from .ipackageManager import IPackageManager
	from tracer.resources.package import Package
	from tracer.resources.collections import PackagesCollection
	from tracer.resources.exceptions import LockedDatabase, DatabasePermissions
	import sqlite3
	import rpm
	import os

	class Rpm(IPackageManager):

		"""
		Package manager class - RPM
		"""

		# noinspection PyMissingConstructor
		def __init__(self, **kwargs):
			self.opts = kwargs

		@property
		def history_path(self): return NotImplemented

		def packages_newer_than(self, unix_time):
			"""
			Returns list of packages which were modified between unix_time and present
			Requires root permissions.
			"""

			# Package manager wasn't used yet
			if not os.path.exists(self.history_path):
				return PackagesCollection([])

			if self.opts.get('modern_swdb'):
				sql = """
					SELECT DISTINCT rpm.name, trans.dt_end AS end

					FROM trans JOIN trans_item JOIN rpm
					ON trans.id=trans_item.trans_id
					AND trans_item.item_id=rpm.item_id

					WHERE trans.dt_begin > ?
					ORDER BY rpm.name
				"""
			else:
				sql = """
					SELECT DISTINCT pkgtups.name, trans_end.timestamp AS end

					FROM trans_beg JOIN trans_end JOIN trans_data_pkgs JOIN pkgtups
					ON trans_beg.tid=trans_end.tid
					AND trans_data_pkgs.tid=trans_beg.tid
					AND trans_data_pkgs.pkgtupid=pkgtups.pkgtupid

					WHERE trans_beg.timestamp > ?
					ORDER BY pkgtups.name
				"""

			try:
				packages = PackagesCollection()
				sqlite = self._database_file()
				conn = sqlite3.connect(sqlite)
				conn.row_factory = sqlite3.Row
				cursor = conn.cursor()
				cursor.execute(sql, [unix_time])

				for result in cursor.fetchall():
					packages.append(Package(result['name'], result['end']))

				return packages

			except sqlite3.OperationalError as e:
				raise LockedDatabase() if str(e) == 'database is locked' else DatabasePermissions()

		def package_files(self, pkg_name):
			"""
			Returns list of files provided by package
			See also: http://docs.fedoraproject.org/en-US/Fedora_Draft_Documentation/0.1/html/RPM_Guide/ch04s02s03.html
			"""
			if self._is_installed(pkg_name):
				ts = rpm.TransactionSet()
				mi = ts.dbMatch("name", pkg_name)
				fi = rpm.fi(next(mi))
				return [f[0] for f in fi]

			# Tracer will not find uninstalled applications
			return []

		def find_package(self, name, evra):
			evra = self._splitEvra(evra)
			ts = rpm.TransactionSet()
			mi = ts.dbMatch("name", name)

			for hdr in mi:
				if hdr[rpm.RPMTAG_EPOCH] == evra[0] and hdr[rpm.RPMTAG_VERSION] == evra[1] and hdr[rpm.RPMTAG_RELEASE] == evra[2] and hdr[rpm.RPMTAG_ARCH] == evra[3]:
					package = Package(name)
					self._load_package_info_from_hdr(package, hdr)

					return package

			return None

		def load_package_info(self, package):
			"""From database load informations about given package and set them to it"""
			if not package:
				return None

			ts = rpm.TransactionSet()
			mi = ts.dbMatch("name", package.name)

			""" Find the latest one if there are multiple versions"""
			latest = None
			for hdr in mi:
				if latest is None:
					latest = hdr
				else:
					compare = rpm.labelCompare((str(latest[rpm.RPMTAG_EPOCH]), str(latest[rpm.RPMTAG_VERSION]), str(latest[rpm.RPMTAG_RELEASE])),
						(str(hdr[rpm.RPMTAG_EPOCH]), str(hdr[rpm.RPMTAG_VERSION]), str(hdr[rpm.RPMTAG_RELEASE])))

					if compare == -1:
						latest = hdr

			if latest is None:
				return

			self._load_package_info_from_hdr(package, latest)

		def compare_packages(self, p1, p2):
			"""
			labelCompare returns:
			0 if the EVR matches
			1 if EVR(1) > EVR(2)
			-1 if EVR(2) > EVR(1)
			"""
			return rpm.labelCompare((str(p1.epoch), str(p1.version), str(p1.release)), (str(p2.epoch), str(p2.version), str(p2.release)))

		def provided_by(self, app):
			"""Returns name of package which provides given application"""
			# `rpm -qf ...` needs full path to binary, not only its name
			process = app.instances[0]  # @TODO Reimplement for all processes
			package = self._file_provided_by(process.exe)
			if package:
				# If package is interpreter, return the package providing that interpreted file
				if package.category == 'Development/Languages':
					for arg in process.cmdline()[1:]:
						if os.path.isfile(arg):
							package = self._file_provided_by(arg)
							return package if package else None
				return package
			return None

		def _splitEvra(self, evra):
			"""
			Derived from rpmUtils.miscutils.splitFilename
			https://github.com/rpm-software-management/yum/blob/master/rpmUtils/miscutils.py

			Given: 9-123a.ia64
			Return: (9, 123a, 1, ia64)
			"""

			archIndex = evra.rfind('.')
			arch = evra[archIndex + 1:]

			relIndex = evra[:archIndex].rfind('-')
			rel = evra[relIndex + 1:archIndex]

			verIndex = evra[:relIndex].rfind('-')
			ver = evra[verIndex + 1:relIndex]

			epochIndex = evra.find(':')
			if epochIndex == -1:
				epoch = None
			else:
				epoch = evra[:epochIndex]

			return epoch, ver, rel, arch

		def _load_package_info_from_hdr(self, package, hdr):
			package.description = hdr[rpm.RPMTAG_SUMMARY]
			package.category = hdr[rpm.RPMTAG_GROUP]

			epoch = hdr[rpm.RPMTAG_EPOCH]
			if epoch:
				package.epoch = epoch

			package.version = hdr[rpm.RPMTAG_VERSION]
			package.release = hdr[rpm.RPMTAG_RELEASE]

		def _file_provided_by(self, file):
			"""Returns name of package which provides given file"""
			ts = rpm.TransactionSet()
			db = ts.dbMatch("basenames", file)
			if db.count() == 0:
				return None

			pkg = next(db)
			p = Package(pkg[rpm.RPMTAG_NAME])
			p.category = pkg[rpm.RPMTAG_GROUP]
			return p

		def _database_file(self):
			"""Returns path to yum history database file"""
			if self.opts.get('modern_swdb'):
				return self.history_path
			for file in sorted(listdir(self.history_path), reverse=True):
				if file.startswith("history-") and file.endswith(".sqlite"):
					return self.history_path + file

		@staticmethod
		def _is_installed(pkg_name):
			"""Returns True if package is installed"""

			ts = rpm.TransactionSet()
			mi = ts.dbMatch('name', pkg_name)
			return True if len(mi) > 0 else False