# Copyright 2013, Big Switch Networks, Inc.
#
# LoxiGen is licensed under the Eclipse Public License, version 1.0 (EPL), with
# the following special exception:
#
# LOXI Exception
#
# As a special exception to the terms of the EPL, you may distribute libraries
# generated by LoxiGen (LoxiGen Libraries) under the terms of your choice, provided
# that copyright and licensing notices generated by LoxiGen are not altered or removed
# from the LoxiGen Libraries and the notice provided below is (i) included in
# the LoxiGen Libraries, if distributed in source code form and (ii) included in any
# documentation for the LoxiGen Libraries, if distributed in binary form.
#
# Notice: "Copyright 2013, Big Switch Networks, Inc. This library was generated by the LoxiGen Compiler."
#
# You may not use this file except in compliance with the EPL or LOXI Exception. You may obtain
# a copy of the EPL at:
#
# http://www.eclipse.org/legal/epl-v10.html
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# EPL for the specific language governing permissions and limitations
# under the EPL.

import sys

import re
import string
import os
import glob
import copy
import collections
import c_gen.of_g_legacy as of_g
import c_gen.type_maps as type_maps
import c_gen.loxi_utils_legacy as loxi_utils
import loxi_globals
import c_gen.identifiers as identifiers
import pyparsing
import loxi_front_end.parser as parser
import c_gen.translation as translation
import loxi_front_end.frontend as frontend
from loxi_ir import *
from generic_utils import *

root_dir = os.path.dirname(os.path.realpath(__file__))

versions = {}
# TODO:  Put these in a class so they get documented

## Dict indexed by version giving all info related to version
#
# This is local; after processing, the information is stored in
# of_g variables.

def add_class(wire_version, cls, members):
    """
    Process a class for the given version and update the unified
    list of classes as needed.

    @param wire_version The wire version for this class defn
    @param cls The name of the class being added
    @param members The list of members with offsets calculated
    """
    memid = 0

    sig = loxi_utils.class_signature(members)
    if cls in of_g.unified:
        uc = of_g.unified[cls]
        if wire_version in uc:
            debug("Error adding %s to unified. Wire ver %d exists" %
                  (cls, wire_version))
            sys.exit(1)
        uc[wire_version] = {}
        # Check for a matching signature
        for wver in uc:
            if type(wver) != type(0): continue
            if wver == wire_version: continue
            if not "use_version" in uc[wver]:
                if sig == loxi_utils.class_signature(uc[wver]["members"]):
                    log("Matched %s, ver %d to ver %d" %
                          (cls, wire_version, wver))
                    # have a match with existing version
                    uc[wire_version]["use_version"] = wver
                    # What else to do?
                    return
    else:  # Haven't seen this entry before
        log("Adding %s to unified list, ver %d" % (cls, wire_version))
        of_g.unified[cls] = dict(union={})
        uc = of_g.unified[cls]

    # At this point, need to add members for this version
    uc[wire_version] = dict(members = members)

    # Per member processing:
    #  Add to union list (I'm sure there's a better way)
    #  Check if it's a list
    union = uc["union"]
    if not cls in of_g.ordered_members:
        of_g.ordered_members[cls] = []
    for member in members:
        m_name = member["name"]
        m_type = member["m_type"]
        if m_name.find("pad") == 0:
            continue
        if m_name in union:
            if not m_type == union[m_name]["m_type"]:
                debug("ERROR:   CLASS: %s. VERSION %d. MEMBER: %s. TYPE: %s" %
                      (cls, wire_version, m_name, m_type))
                debug("    Type conflict adding member to unified set.")
                debug("    Current union[%s]:" % m_name)
                debug(union[m_name])
                sys.exit(1)
        else:
            union[m_name] = dict(m_type=m_type, memid=memid)
            memid += 1
        if not m_name in of_g.ordered_members[cls]:
            of_g.ordered_members[cls].append(m_name)

def update_offset(cls, wire_version, name, offset, m_type):
    """
    Update (and return) the offset based on type.
    @param cls The parent class
    @param wire_version The wire version being processed
    @param name The name of the data member
    @param offset The current offset
    @param m_type The type declaration being processed
    @returns A pair (next_offset, len_update)  next_offset is the new offset
    of the next object or -1 if this is a var-length object.  len_update
    is the increment that should be added to the length.  Note that (for
    of_match_v3) it is variable length, but it adds 8 bytes to the fixed
    length of the object
    If offset is already -1, do not update
    Otherwise map to base type and count and update (if possible)
    """
    if offset < 0:    # Don't update offset once set to -1
        return offset, 0

    count, base_type = loxi_utils.type_dec_to_count_base(m_type)

    len_update = 0
    if base_type in of_g.of_mixed_types:
        base_type = of_g.of_mixed_types[base_type][wire_version]

    base_class = base_type[:-2]
    if (base_class, wire_version) in of_g.is_fixed_length:
        bytes = of_g.base_length[(base_class, wire_version)]
    else:
        if base_type == "of_match_v3_t":
            # This is a special case: it has non-zero min length
            # but is variable length
            bytes = -1
            len_update = 8
        elif base_type == "of_oxm_header_t":
            # This is a special case: it has non-zero min length
            # but is variable length
            bytes = -1
            len_update = 4
        elif base_type in of_g.of_base_types:
            bytes = of_g.of_base_types[base_type]["bytes"]
        else:
            print "UNKNOWN TYPE for %s %s: %s" % (cls, name, base_type)
            log("UNKNOWN TYPE for %s %s: %s" % (cls, name, base_type))
            bytes = -1

    # If bytes
    if bytes > 0:
        len_update = count * bytes

    if bytes == -1:
        return -1, len_update

    return offset + (count * bytes), len_update

def calculate_offsets_and_lengths(ordered_classes, classes, wire_version):
    """
    Generate the offsets for fixed offset class members
    Also calculate the class_sizes when possible.

    @param classes The classes to process
    @param wire_version The wire version for this set of classes

    Updates global variables
    """

    lists = set()

    # Generate offsets
    for cls in ordered_classes:
        fixed_offset = 0 # The last "good" offset seen
        offset = 0
        last_offset = 0
        last_name = "-"
        for member in classes[cls]:
            m_type = member["m_type"]
            name = member["name"]
            if last_offset == -1:
                if name == "pad":
                    log("Skipping pad for special offset for %s" % cls)
                else:
                    log("SPECIAL OFS: Member %s (prev %s), class %s ver %d" %
                          (name, last_name, cls, wire_version))
                    if (((cls, name) in of_g.special_offsets) and
                        (of_g.special_offsets[(cls, name)] != last_name)):
                        debug("ERROR: special offset prev name changed")
                        debug("  cls %s. name %s. version %d. was %s. now %s" %
                              cls, name, wire_version,
                              of_g.special_offsets[(cls, name)], last_name)
                        sys.exit(1)
                    of_g.special_offsets[(cls, name)] = last_name

            member["offset"] = offset
            if m_type.find("list(") == 0:
                (list_name, base_type) = loxi_utils.list_name_extract(m_type)
                lists.add(list_name)
                member["m_type"] = list_name + "_t"
                offset = -1
            elif m_type.find("struct") == 0:
                debug("ERROR found struct: %s.%s " % (cls, name))
                sys.exit(1)
            elif m_type == "octets":
                log("offset gen skipping octets: %s.%s " % (cls, name))
                offset = -1
            else:
                offset, len_update = update_offset(cls, wire_version, name,
                                                  offset, m_type)
                if offset != -1:
                    fixed_offset = offset
                else:
                    fixed_offset += len_update
                    log("offset is -1 for %s.%s version %d " %
                        (cls, name, wire_version))
            last_offset = offset
            last_name = name
        of_g.base_length[(cls, wire_version)] = fixed_offset
        if (offset != -1):
            of_g.is_fixed_length.add((cls, wire_version))
    for list_type in lists:
        classes[list_type] = []
        of_g.ordered_classes[wire_version].append(list_type)
        of_g.base_length[(list_type, wire_version)] = 0

def order_and_assign_object_ids():
    """
    Order all classes and assign object ids to all classes.

    This is done to promote a reasonable order of the objects, putting
    messages first followed by non-messages.  No assumptions should be
    made about the order, nor about contiguous numbering.  However, the
    numbers should all be reasonably small allowing arrays indexed by
    these enum values to be defined.
    """

    # Generate separate message and non-message ordered lists
    for cls in of_g.unified:
        if loxi_utils.class_is_message(cls):
            of_g.ordered_messages.append(cls)
        elif loxi_utils.class_is_list(cls):
            of_g.ordered_list_objects.append(cls)
        else:
            of_g.ordered_non_messages.append(cls)

    of_g.ordered_messages.sort()
    of_g.ordered_pseudo_objects.sort()
    of_g.ordered_non_messages.sort()
    of_g.ordered_list_objects.sort()
    of_g.standard_class_order.extend(of_g.ordered_messages)
    of_g.standard_class_order.extend(of_g.ordered_non_messages)
    of_g.standard_class_order.extend(of_g.ordered_list_objects)

    # This includes pseudo classes for which most code is not generated
    of_g.all_class_order.extend(of_g.ordered_messages)
    of_g.all_class_order.extend(of_g.ordered_non_messages)
    of_g.all_class_order.extend(of_g.ordered_list_objects)
    of_g.all_class_order.extend(of_g.ordered_pseudo_objects)

    # Assign object IDs
    for cls in of_g.ordered_messages:
        of_g.unified[cls]["object_id"] = of_g.object_id
        of_g.object_id += 1
    for cls in of_g.ordered_non_messages:
        of_g.unified[cls]["object_id"] = of_g.object_id
        of_g.object_id += 1
    for cls in of_g.ordered_list_objects:
        of_g.unified[cls]["object_id"] = of_g.object_id
        of_g.object_id += 1


def initialize_versions():
    """
    Create an empty datastructure for each target version.
    """

    for version in loxi_globals.OFVersions.target_versions:
        wire_version = version.wire_version
        version_name = of_g.of_version_wire2name[wire_version]
        of_g.wire_ver_map[wire_version] = version_name
        versions[version_name] = dict(
            version_name = version_name,
            wire_version = wire_version,
            classes = {})
        of_g.ordered_classes[wire_version] = []

    of_g.target_version_list = [ v.wire_version for v in loxi_globals.OFVersions.target_versions ]

def build_ordered_classes():
    """
    Read in from files given on command line and update global state

    @fixme Should select versions to support from command line
    """

    for version, protocol in loxi_globals.ir.items():
        wire_version = version.wire_version
        # Populate global state
        version_name = of_g.of_version_wire2name[wire_version]

        for ofclass in protocol.classes:
            of_g.ordered_classes[wire_version].append(ofclass.name)
            legacy_members = []
            pad_count = 0
            for m in ofclass.members:
                if type(m) == OFPadMember:
                    m_name = 'pad%d' % pad_count
                    if m_name == 'pad0': m_name = 'pad'
                    legacy_members.append(dict(m_type='uint8_t[%d]' % m.length,
                                               name=m_name))
                    pad_count += 1
                else:
                    # HACK the C backend does not yet support of_oxm_t
                    if m.oftype == 'of_oxm_t':
                        m_type = 'of_oxm_header_t'
                    else:
                        enum = find(lambda e: e.name == m.oftype, protocol.enums)
                        if enum and "wire_type" in enum.params:
                            m_type = enum.params["wire_type"]
                        else:
                            m_type = m.oftype
                    legacy_members.append(dict(m_type=m_type, name=m.name))
            versions[version_name]['classes'][ofclass.name] = legacy_members

        for enum in protocol.enums:
            for entry in enum.entries:
                identifiers.add_identifier(
                    translation.loxi_name(entry.name),
                    entry.name, enum.name, entry.value, wire_version,
                    of_g.identifiers, of_g.identifiers_by_group)

def populate_type_maps():
    """
    Use the type members in the IR to fill out the legacy type_maps.
    """

    def split_inherited_cls(cls):
        if cls == 'of_meter_band_stats': # HACK not a subtype of of_meter_band
            return None, None
        for parent in sorted(type_maps.inheritance_data.keys(), reverse=True):
            if cls.startswith(parent):
                return (parent, cls[len(parent)+1:])
        return None, None

    def find_experimenter(parent, cls):
        for experimenter in sorted(of_g.experimenter_name_to_id.keys(), reverse=True):
            prefix = parent + '_' + experimenter
            if cls.startswith(prefix) and cls != prefix:
                return experimenter
        return None

    def find_type_value(ofclass, m_name):
        for m in ofclass.members:
            if isinstance(m, OFTypeMember) and m.name == m_name:
                return m.value
        raise KeyError("ver=%d, cls=%s, m_name=%s" % (wire_version, cls, m_name))

    # Most inheritance classes: actions, instructions, etc
    for version, protocol in loxi_globals.ir.items():
        wire_version = version.wire_version
        for ofclass in protocol.classes:
            cls = ofclass.name
            parent, subcls = split_inherited_cls(cls)
            if not (parent and subcls):
                continue
            if parent == 'of_oxm':
                type_len = find_type_value(ofclass, 'type_len')
                oxm_class = (type_len >> 16) & 0xffff
                if oxm_class != 0x8000:
                    # Do not include experimenter OXMs in the main table
                    val = type_maps.invalid_type
                else:
                    val = (type_len >> 8) & 0xff
            else:
                val = find_type_value(ofclass, 'type')
            type_maps.inheritance_data[parent][wire_version][subcls] = val

            # Extensions (only actions for now)
            experimenter = find_experimenter(parent, cls)
            if parent == 'of_action' and experimenter:
                val = find_type_value(ofclass, 'subtype')
                type_maps.extension_action_subtype[wire_version][experimenter][cls] = val
                if wire_version >= of_g.VERSION_1_3:
                    cls2 = parent + "_id" + cls[len(parent):]
                    type_maps.extension_action_id_subtype[wire_version][experimenter][cls2] = val
            elif parent == 'of_instruction' and experimenter:
                val = find_type_value(ofclass, 'subtype')
                type_maps.extension_instruction_subtype[wire_version][experimenter][cls] = val

    # Messages
    for version, protocol in loxi_globals.ir.items():
        wire_version = version.wire_version
        for ofclass in protocol.classes:
            cls = ofclass.name
            # HACK (though this is what loxi_utils.class_is_message() does)
            if not [x for x in ofclass.members if isinstance(x, OFDataMember) and x.name == 'xid']:
                continue
            if type_maps.class_is_virtual(cls):
                continue
            subcls = cls[3:]
            val = find_type_value(ofclass, 'type')
            if not val in type_maps.message_types[wire_version].values():
                type_maps.message_types[wire_version][subcls] = val

            # Extensions
            experimenter = find_experimenter('of', cls)
            if experimenter and ofclass.is_subclassof("of_experimenter"):
                val = find_type_value(ofclass, 'subtype')
                type_maps.extension_message_subtype[wire_version][experimenter][cls] = val

    type_maps.generate_maps()

def analyze_input():
    """
    Add information computed from the input, including offsets and
    lengths of struct members and the set of list and action_id types.
    """

    # Generate header classes for inheritance parents
    for wire_version, ordered_classes in of_g.ordered_classes.items():
        classes = versions[of_g.of_version_wire2name[wire_version]]['classes']
        for cls in ordered_classes:
            if cls in type_maps.inheritance_map:
                new_cls = cls + '_header'
                of_g.ordered_classes[wire_version].append(new_cls)
                classes[new_cls] = classes[cls]

    for wire_version in of_g.wire_ver_map.keys():
        version_name = of_g.of_version_wire2name[wire_version]
        calculate_offsets_and_lengths(
            of_g.ordered_classes[wire_version],
            versions[version_name]['classes'],
            wire_version)

def unify_input():
    """
    Create Unified View of Objects
    """

    global versions

    # Add classes to unified in wire-format order so that it is easier
    # to generate things later
    keys = versions.keys()
    keys.sort(reverse=True)
    for version in keys:
        wire_version = versions[version]["wire_version"]
        classes = versions[version]["classes"]
        for cls in of_g.ordered_classes[wire_version]:
            add_class(wire_version, cls, classes[cls])