# Copyright 1999-2012 Gentoo Foundation
# Distributed under the terms of the GNU General Public License v2

import sys
from portage.dbapi import dbapi
from portage.dbapi.dep_expand import dep_expand

class PackageVirtualDbapi(dbapi):
	"""
	A dbapi-like interface class that represents the state of the installed
	package database as new packages are installed, replacing any packages
	that previously existed in the same slot. The main difference between
	this class and fakedbapi is that this one uses Package instances
	internally (passed in via cpv_inject() and cpv_remove() calls).
	"""
	def __init__(self, settings):
		dbapi.__init__(self)
		self.settings = settings
		self._match_cache = {}
		self._cp_map = {}
		self._cpv_map = {}

	def clear(self):
		"""
		Remove all packages.
		"""
		if self._cpv_map:
			self._clear_cache()
			self._cp_map.clear()
			self._cpv_map.clear()

	def copy(self):
		obj = PackageVirtualDbapi(self.settings)
		obj._match_cache = self._match_cache.copy()
		obj._cp_map = self._cp_map.copy()
		for k, v in obj._cp_map.items():
			obj._cp_map[k] = v[:]
		obj._cpv_map = self._cpv_map.copy()
		return obj

	def __bool__(self):
		return bool(self._cpv_map)

	if sys.hexversion < 0x3000000:
		__nonzero__ = __bool__

	def __iter__(self):
		return iter(self._cpv_map.values())

	def __contains__(self, item):
		existing = self._cpv_map.get(item.cpv)
		if existing is not None and \
			existing == item:
			return True
		return False

	def get(self, item, default=None):
		cpv = getattr(item, "cpv", None)
		if cpv is None:
			if len(item) != 5:
				return default
			type_name, root, cpv, operation, repo_key = item

		existing = self._cpv_map.get(cpv)
		if existing is not None and \
			existing == item:
			return existing
		return default

	def match_pkgs(self, atom):
		return [self._cpv_map[cpv] for cpv in self.match(atom)]

	def _clear_cache(self):
		if self._categories is not None:
			self._categories = None
		if self._match_cache:
			self._match_cache = {}

	def match(self, origdep, use_cache=1):
		atom = dep_expand(origdep, mydb=self, settings=self.settings)
		cache_key = (atom, atom.unevaluated_atom)
		result = self._match_cache.get(cache_key)
		if result is not None:
			return result[:]
		result = list(self._iter_match(atom, self.cp_list(atom.cp)))
		self._match_cache[cache_key] = result
		return result[:]

	def cpv_exists(self, cpv, myrepo=None):
		return cpv in self._cpv_map

	def cp_list(self, mycp, use_cache=1):
		# NOTE: Cache can be safely shared with the match cache, since the
		# match cache uses the result from dep_expand for the cache_key.
		cache_key = (mycp, mycp)
		cachelist = self._match_cache.get(cache_key)
		if cachelist is not None:
			return cachelist[:]
		cpv_list = self._cp_map.get(mycp)
		if cpv_list is None:
			cpv_list = []
		else:
			cpv_list = [pkg.cpv for pkg in cpv_list]
		self._cpv_sort_ascending(cpv_list)
		self._match_cache[cache_key] = cpv_list
		return cpv_list[:]

	def cp_all(self):
		return list(self._cp_map)

	def cpv_all(self):
		return list(self._cpv_map)

	def cpv_inject(self, pkg):
		cp_list = self._cp_map.get(pkg.cp)
		if cp_list is None:
			cp_list = []
			self._cp_map[pkg.cp] = cp_list
		e_pkg = self._cpv_map.get(pkg.cpv)
		if e_pkg is not None:
			if e_pkg == pkg:
				return
			self.cpv_remove(e_pkg)
		for e_pkg in cp_list:
			if e_pkg.slot_atom == pkg.slot_atom:
				if e_pkg == pkg:
					return
				self.cpv_remove(e_pkg)
				break
		cp_list.append(pkg)
		self._cpv_map[pkg.cpv] = pkg
		self._clear_cache()

	def cpv_remove(self, pkg):
		old_pkg = self._cpv_map.get(pkg.cpv)
		if old_pkg != pkg:
			raise KeyError(pkg)
		self._cp_map[pkg.cp].remove(pkg)
		del self._cpv_map[pkg.cpv]
		self._clear_cache()

	def aux_get(self, cpv, wants, myrepo=None):
		metadata = self._cpv_map[cpv]._metadata
		return [metadata.get(x, "") for x in wants]

	def aux_update(self, cpv, values):
		self._cpv_map[cpv]._metadata.update(values)
		self._clear_cache()