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# Revision $Id: msgs.py 10477 2010-07-22 18:37:12Z jfaust $
# $Author: jfaust $
"""
ROS msg library for Python

Implements: U{http://ros.org/wiki/msg}
"""

import cStringIO
import os
import itertools
import sys
import re
import string

import roslib.exceptions
import roslib.manifest
import roslib.packages
import roslib.names
import roslib.resources
import roslib.rospack

VERBOSE = False

## @return: True if msg-related scripts should print verbose output
def is_verbose():
    return VERBOSE

## set whether msg-related scripts should print verbose output
def set_verbose(v):
    global VERBOSE
    VERBOSE = v

EXT = roslib.names.MSG_EXT #alias
SEP = roslib.names.PRN_SEPARATOR #e.g. std_msgs/String
## character that designates a constant assignment rather than a field
CONSTCHAR   = '='
COMMENTCHAR = '#'

class MsgSpecException(roslib.exceptions.ROSLibException): pass

#TODOXXX: unit test
def base_msg_type(type_):
    """
    Compute the base data type, e.g. for arrays, get the underlying array item type
    @param type_: ROS msg type (e.g. 'std_msgs/String')
    @type  type_: str
    @return: base type
    @rtype: str
    """
    if type_ is None:
        return None
    if '[' in type_:
        return type_[:type_.find('[')]
    return type_

def resolve_type(type_, package_context):
    """
    Resolve type name based on current package context.

    NOTE: in ROS, 'Header' always resolves to 'roslib/Header'

    e.g.::
      resolve_type('String', 'std_msgs') -> 'std_msgs/String'
      resolve_type('String[]', 'std_msgs') -> 'std_msgs/String[]'
      resolve_type('std_msgs/String', 'foo') -> 'std_msgs/String'    
      resolve_type('uint16', 'std_msgs') -> 'uint16'
      resolve_type('uint16[]', 'std_msgs') -> 'uint16[]'
    """
    bt = base_msg_type(type_)
    if bt in BUILTIN_TYPES:
        return type_
    elif bt == 'Header':
        return 'roslib/Header'
    elif SEP in type_:
        return type_
    else:
        return "%s%s%s"%(package_context, SEP, type_)    

#NOTE: this assumes that we aren't going to support multi-dimensional

def parse_type(type_):
    """
    Parse ROS message field type
    @param type_: ROS field type
    @type  type_: str
    @return: base_type, is_array, array_length
    @rtype: str, bool, int
    @raise MsgSpecException: if type_ cannot be parsed
    """
    if not type_:
        raise MsgSpecException("Invalid empty type")
    if '[' in type_:
        var_length = type_.endswith('[]')
        splits = type_.split('[')
        if len(splits) > 2:
            raise MsgSpecException("Currently only support 1-dimensional array types: %s"%type_)
        if var_length:
            return type_[:-2], True, None
        else:
            try:
                length = int(splits[1][:-1])
                return splits[0], True, length
            except ValueError:
                raise MsgSpecException("Invalid array dimension: [%s]"%splits[1][:-1])
    else:
        return type_, False, None
   
################################################################################
# name validation 

def is_valid_msg_type(x):
    """
    @return: True if the name is a syntatically legal message type name
    @rtype: bool
    """
    if not x or len(x) != len(x.strip()):
        return False
    base = base_msg_type(x)
    if not roslib.names.is_legal_resource_name(base):
        return False
    #parse array indicies
    x = x[len(base):]
    state = 0
    i = 0
    for c in x:
        if state == 0:
            if c != '[':
                return False
            state = 1 #open
        elif state == 1:
            if c == ']':
                state = 0 #closed
            else:
                try:
                    string.atoi(c)
                except:
                    return False
    return state == 0

def is_valid_constant_type(x):
    """
    @return: True if the name is a legal constant type. Only simple types are allowed.
    @rtype: bool
    """
    return x in PRIMITIVE_TYPES

def is_valid_msg_field_name(x):
    """
    @return: True if the name is a syntatically legal message field name
    @rtype: bool
    """
    return roslib.names.is_legal_resource_base_name(x)

# msg spec representation ##########################################

class Constant(object):
    """
    Container class for holding a Constant declaration
    """
    __slots__ = ['type', 'name', 'val', 'val_text']
    
    def __init__(self, type_, name, val, val_text):
        """
        @param type_: constant type
        @type  type_: str 
        @param name: constant name
        @type  name: str
        @param val: constant value
        @type  val: str
        @param val_text: Original text definition of \a val
        @type  val_text: str
        """
        if type is None or name is None or val is None or val_text is None:
            raise ValueError('Constant must have non-None parameters')
        self.type = type_
        self.name = name.strip() #names are always stripped of whitespace
        self.val = val
        self.val_text = val_text

    def __eq__(self, other):
        if not isinstance(other, Constant):
            return False
        return self.type == other.type and self.name == other.name and self.val == other.val

    def __repr__(self):
        return "%s %s=%s"%(self.type, self.name, self.val)

    def __str__(self):
        return "%s %s=%s"%(self.type, self.name, self.val)

def _strify_spec(spec, buff=None, indent=''):
    """
    Convert spec into a string representation. Helper routine for MsgSpec.
    @param indent: internal use only
    @type  indent: str
    @param buff: internal use only
    @type  buff: StringIO
    @return: string representation of spec
    @rtype: str
    """
    if buff is None:
        buff = cStringIO.StringIO()
    for c in spec.constants:
        buff.write("%s%s %s=%s\n"%(indent, c.type, c.name, c.val_text))
    for type_, name in zip(spec.types, spec.names):
        buff.write("%s%s %s\n"%(indent, type_, name))
        base_type = base_msg_type(type_)
        if not base_type in BUILTIN_TYPES:
            subspec = get_registered(base_type)
            _strify_spec(subspec, buff, indent + '  ')
    return buff.getvalue()

class Field(object):
    """
    Container class for storing information about a single field in a MsgSpec
    
    Contains:
    name
    type
    base_type
    is_array
    array_len
    is_builtin
    is_header
    """
    
    def __init__(self, name, type):
        self.name = name
        self.type = type
        (self.base_type, self.is_array, self.array_len) = parse_type(type)
        self.is_header = is_header_type(self.base_type)
        self.is_builtin = is_builtin(self.base_type)

    def __repr__(self):
        return "[%s, %s, %s, %s, %s]"%(self.name, self.type, self.base_type, self.is_array, self.array_len)

class MsgSpec(object):
    """
    Container class for storing loaded msg description files. Field
    types and names are stored in separate lists with 1-to-1
    correspondence. MsgSpec can also return an md5 of the source text.
    """

    def __init__(self, types, names, constants, text, full_name = '', short_name = '', package = ''):
        """
        @param types: list of field types, in order of declaration
        @type  types: [str]
        @param names: list of field names, in order of declaration    
        @type  names: [str]
        @param constants: Constant declarations
        @type  constants: [L{Constant}]
        @param text: text of declaration
        @type  text: str
        @raise MsgSpecException: if spec is invalid (e.g. fields with the same name)
        """
        self.types = types
        if len(set(names)) != len(names):
            raise MsgSpecException("Duplicate field names in message: %s"%names)
        self.names = names
        self.constants = constants
        assert len(self.types) == len(self.names), "len(%s) != len(%s)"%(self.types, self.names)
        #Header.msg support
        if (len(self.types)):
            self.header_present = self.types[0] == HEADER and self.names[0] == 'header'
        else:
            self.header_present = False
        self.text = text
        self.full_name = full_name
        self.short_name = short_name
        self.package = package
        self._parsed_fields = [Field(name, type) for (name, type) in zip(self.names, self.types)]
        
    def fields(self):
        """
        @return: zip list of types and names (e.g. [('int32', 'x'), ('int32', 'y')]
        @rtype: [(str,str),]
        """
        return zip(self.types, self.names)
    
    def parsed_fields(self):
        """
        @return: list of Field classes
        @rtype: [Field,]
        """
        return self._parsed_fields

    def has_header(self):
        """
        @return: True if msg decription contains a 'Header header'
        declaration at the beginning
        @rtype: bool
        """
        return self.header_present
    def __eq__(self, other):
        if not other or not isinstance(other, MsgSpec):
            return False 
        return self.types == other.types and self.names == other.names and \
               self.constants == other.constants and self.text == other.text
    def __ne__(self, other):
        if not other or not isinstance(other, MsgSpec):
            return True
        return not self.__eq__(other)

    def __repr__(self):
        if self.constants:
            return "MsgSpec[%s, %s, %s]"%(repr(self.constants), repr(self.types), repr(self.names))
        else:
            return "MsgSpec[%s, %s]"%(repr(self.types), repr(self.names))        

    def __str__(self):
        return _strify_spec(self)
    
# msg spec loading utilities ##########################################

def reinit():
    """
    Reinitialize roslib.msgs. This API is for message generators
    (e.g. genpy) that need to re-initialize the registration table.
    """
    global _initialized , _loaded_packages
    # unset the initialized state and unregister everything 
    _initialized = False
    del _loaded_packages[:]
    REGISTERED_TYPES.clear()
    _init()
    
_initialized = False
def _init():
    #lazy-init
    global _initialized
    if _initialized:
        return

    fname = '%s%s'%(HEADER, EXT)
    roslib_dir = roslib.packages.get_pkg_dir('roslib')
    if roslib_dir is None:
        raise MsgSpecException("Unable to locate roslib: %s files cannot be loaded"%EXT)
    
    header = os.path.join(roslib_dir, roslib.packages.MSG_DIR, fname)
    if not os.path.isfile(header):
        print >> sys.stderr, "ERROR: cannot locate %s. Excepted to find it at '%s'"%(fname, header)
        return False

    # register Header under both contexted and de-contexted name
    _, spec = load_from_file(header, '')
    register(HEADER, spec)
    register('roslib/'+HEADER, spec)    
    for k, spec in EXTENDED_BUILTINS.iteritems():
        register(k, spec)
        
    _initialized = True

# .msg file routines ##############################################################       

def _msg_filter(f):
    """
    Predicate for filtering directory list. matches message files
    @param f: filename
    @type  f: str
    """
    return os.path.isfile(f) and f.endswith(EXT)

# also used by doxymaker
def list_msg_types(package, include_depends):
    """
    List all messages in the specified package
    @param package str: name of package to search
    @param include_depends bool: if True, will also list messages in package dependencies
    @return [str]: message type names
    """
    types = roslib.resources.list_package_resources(package, include_depends, roslib.packages.MSG_DIR, _msg_filter)
    return [x[:-len(EXT)] for x in types]

def msg_file(package, type_):
    """
    Determine the file system path for the specified .msg
    resource. .msg resource does not have to exist.
    
    @param package: name of package .msg file is in
    @type  package: str
    @param type_: type name of message, e.g. 'Point2DFloat32'
    @type  type_: str
    @return: file path of .msg file in specified package
    @rtype: str
    """
    return roslib.packages.resource_file(package, roslib.packages.MSG_DIR, type_+EXT)

def get_pkg_msg_specs(package):
    """
    List all messages that a package contains.
    
    @param package: package to load messages from
    @type  package: str
    @return: list of message type names and specs for package, as well as a list
        of message names that could not be processed. 
    @rtype: [(str, L{MsgSpec}), [str]]
    """
    _init()
    types = list_msg_types(package, False)
    specs = [] #no fancy list comprehension as we want to show errors
    failures = []
    for t in types:
        try: 
            typespec = load_from_file(msg_file(package, t), package)
            specs.append(typespec)
        except Exception, e:
            failures.append(t)
            print "ERROR: unable to load %s"%t
    return specs, failures

def load_package_dependencies(package, load_recursive=False):
    """
    Register all messages that the specified package depends on.
    
    @param load_recursive: (optional) if True, load all dependencies,
        not just direct dependencies. By default, this is false to
        prevent packages from incorrectly inheriting dependencies.
    @type  load_recursive: bool
    """
    global _loaded_packages
    _init()    
    if VERBOSE:
        print "Load dependencies for package", package
        
    if not load_recursive:
        manifest_file = roslib.manifest.manifest_file(package, True)
        m = roslib.manifest.parse_file(manifest_file)
        depends = [d.package for d in m.depends] # #391
    else:
        depends = roslib.rospack.rospack_depends(package)

    msgs = []
    failures = []
    for d in depends:
        if VERBOSE:
            print "Load dependency", d
        #check if already loaded
        # - we are dependent on manifest.getAll returning first-order dependencies first
        if d in _loaded_packages or d == package:
            continue
        _loaded_packages.append(d)
        specs, failed = get_pkg_msg_specs(d)
        msgs.extend(specs)
        failures.extend(failed)
    for key, spec in msgs:
        register(key, spec)

def load_package(package):
    """
    Load package into the local registered namespace. All messages found
    in the package will be registered if they are successfully
    loaded. This should only be done with one package (i.e. the 'main'
    package) per Python instance.

    @param package: package name
    @type  package: str
    """
    global _loaded_packages
    _init()    
    if VERBOSE:
        print "Load package", package
        
    #check if already loaded
    # - we are dependent on manifest.getAll returning first-order dependencies first
    if package in _loaded_packages:
        if VERBOSE:
            print "Package %s is already loaded"%package
        return

    _loaded_packages.append(package)
    specs, failed = get_pkg_msg_specs(package)
    if VERBOSE:
        print "Package contains the following messages: %s"%specs
    for key, spec in specs:
        #register spec under both local and fully-qualified key
        register(key, spec)
        register(package + roslib.names.PRN_SEPARATOR + key, spec)        

def _convert_val(type_, val):
    """
    Convert constant value declaration to python value. Does not do
    type-checking, so ValueError or other exceptions may be raised.
    
    @param type_: ROS field type
    @type  type_: str
    @param val: string representation of constant
    @type  val: str:
    @raise ValueError: if unable to convert to python representation
    @raise MsgSpecException: if value exceeds specified integer width
    """
    if type_ in ['float32','float64']:
        return float(val)
    elif type_ in ['string']:
        return val.strip() #string constants are always stripped 
    elif type_ in ['int8', 'uint8', 'int16','uint16','int32','uint32','int64','uint64', 'char', 'byte']:
        # bounds checking
        bits = [('int8', 8), ('uint8', 8), ('int16', 16),('uint16', 16),\
                ('int32', 32),('uint32', 32), ('int64', 64),('uint64', 64),\
                ('byte', 8), ('char', 8)]
        b = [b for t, b in bits if t == type_][0]
        import math
        if type_[0] == 'u' or type_ == 'char':
            lower = 0
            upper = int(math.pow(2, b)-1)
        else:
            upper = int(math.pow(2, b-1)-1)   
            lower = -upper - 1 #two's complement min
        val = int(val) #python will autocast to long if necessary
        if val > upper or val < lower:
            raise MsgSpecException("cannot coerce [%s] to %s (out of bounds)"%(val, type_))
        return val
    elif type_ == 'bool':
        # TODO: need to nail down constant spec for bool
        return True if eval(val) else False
    raise MsgSpecException("invalid constant type: [%s]"%type_)
        
def load_by_type(msgtype, package_context=''):
    """
    Load message specification for specified type
    
    @param package_context: package name to use for the type name or
        '' to use the local (relative) naming convention.
    @type  package_context: str
    @return: Message type name and message specification
    @rtype: (str, L{MsgSpec})
    """
    pkg, basetype = roslib.names.package_resource_name(msgtype)
    pkg = pkg or package_context # convert '' -> local package
    try:
        m_f = msg_file(pkg, basetype)
    except roslib.packages.InvalidROSPkgException:
        raise MsgSpecException("Cannot locate message type [%s], package [%s] does not exist"%(msgtype, pkg)) 
    return load_from_file(m_f, pkg)

def load_from_string(text, package_context='', full_name='', short_name=''):
    """
    Load message specification from a string.
    @param text: .msg text 
    @type  text: str
    @param package_context: package name to use for the type name or
        '' to use the local (relative) naming convention.
    @type  package_context: str
    @return: Message specification
    @rtype: L{MsgSpec}
    @raise MsgSpecException: if syntax errors or other problems are detected in file
    """
    types = []
    names = []
    constants = []
    for orig_line in text.split('\n'):
        l = orig_line.split(COMMENTCHAR)[0].strip() #strip comments
        if not l:
            continue #ignore empty lines
        splits = filter(lambda s: s, [x.strip() for x in l.split(" ")]) #split type/name, filter out empties
        type_ = splits[0]
        if not is_valid_msg_type(type_):
            raise MsgSpecException("%s is not a legal message type"%type_)
        if CONSTCHAR in l:
            if not is_valid_constant_type(type_):
                raise MsgSpecException("%s is not a legal constant type"%type_)
            if type_ == 'string':
                # strings contain anything to the right of the equals sign, there are no comments allowed
                idx = orig_line.find(CONSTCHAR)
                name = orig_line[orig_line.find(' ')+1:idx]
                val = orig_line[idx+1:]
            else:
                splits = [x.strip() for x in ' '.join(splits[1:]).split(CONSTCHAR)] #resplit on '='
                if len(splits) != 2:
                    raise MsgSpecException("Invalid declaration: %s"%l)
                name = splits[0]
                val = splits[1]
            try:
                val_converted  = _convert_val(type_, val)
            except Exception, e:
                raise MsgSpecException("Invalid declaration: %s"%e)
            constants.append(Constant(type_, name, val_converted, val.strip()))
        else:
            if len(splits) != 2:
                raise MsgSpecException("Invalid declaration: %s"%l)
            name = splits[1]
            if not is_valid_msg_field_name(name):
                raise MsgSpecException("%s is not a legal message field name"%name)
            if package_context and not SEP in type_:
                if not base_msg_type(type_) in RESERVED_TYPES:
                    #print "rewrite", type_, "to", "%s/%s"%(package_context, type_)
                    type_ = "%s/%s"%(package_context, type_)
            types.append(type_)
            names.append(name)
    return MsgSpec(types, names, constants, text, full_name, short_name, package_context)

def load_from_file(file_path, package_context=''):
    """
    Convert the .msg representation in the file to a MsgSpec instance.
    This does *not* register the object.
    @param file_path: path of file to load from
    @type  file_path: str:
    @param package_context: package name to prepend to type name or
        '' to use local (relative) naming convention.
    @type  package_context: str
    @return: Message type name and message specification
    @rtype:  (str, L{MsgSpec})
    @raise MsgSpecException: if syntax errors or other problems are detected in file
    """
    if VERBOSE:
        if package_context:
            print "Load spec from", file_path, "into package [%s]"%package_context
        else:
            print "Load spec from", file_path

    file_name = os.path.basename(file_path)
    type_ = file_name[:-len(EXT)]
    base_type_ = type_
    # determine the type name
    if package_context:
        while package_context.endswith(SEP):
            package_context = package_context[:-1] #strip message separators
        type_ = "%s%s%s"%(package_context, SEP, type_)
    if not roslib.names.is_legal_resource_name(type_):
        raise MsgSpecException("%s: [%s] is not a legal type name"%(file_path, type_))
    
    f = open(file_path, 'r')
    try:
        try:
            text = f.read()
            return (type_, load_from_string(text, package_context, type_, base_type_))
        except MsgSpecException, e:
            raise MsgSpecException('%s: %s'%(file_name, e))
    finally:
        f.close()

# data structures and builtins specification ###########################

# adjustable constants, in case we change our minds
HEADER   = 'Header'
TIME     = 'time'
DURATION = 'duration'

def is_header_type(type_):
    """
    @param type_: message type name
    @type  type_: str
    @return: True if \a type_ refers to the ROS Header type
    @rtype:  bool
    """
    return type_ in [HEADER, 'roslib/Header']
       
# time and duration types are represented as aggregate data structures
# for the purposes of serialization from the perspective of
# roslib.msgs. genmsg_py will do additional special handling is required
# to convert them into rospy.msg.Time/Duration instances.

## time as msg spec. time is unsigned 
TIME_MSG     = "uint32 secs\nuint32 nsecs"
## duration as msg spec. duration is just like time except signed
DURATION_MSG = "int32 secs\nint32 nsecs"

## primitive types are those for which we allow constants, i.e. have  primitive representation
PRIMITIVE_TYPES = ['int8','uint8','int16','uint16','int32','uint32','int64','uint64','float32','float64',
                   'string',
                   'bool',
                   # deprecated:
                   'char','byte']
BUILTIN_TYPES = PRIMITIVE_TYPES + [TIME, DURATION]

def is_builtin(msg_type_name):
    """
    @param msg_type_name: name of message type
    @type  msg_type_name: str
    @return: True if msg_type_name is a builtin/primitive type
    @rtype: bool
    """
    return msg_type_name in BUILTIN_TYPES

## extended builtins are builtin types that can be represented as MsgSpec instances
EXTENDED_BUILTINS = { TIME : load_from_string(TIME_MSG), DURATION: load_from_string(DURATION_MSG) }

RESERVED_TYPES  = BUILTIN_TYPES + [HEADER]

REGISTERED_TYPES = { } 
_loaded_packages = [] #keep track of packages so that we only load once (note: bug #59)

def is_registered(msg_type_name):
    """
    @param msg_type_name: name of message type
    @type  msg_type_name: str
    @return: True if msg spec for specified msg type name is
    registered. NOTE: builtin types are not registered.
    @rtype: bool
    """
    return REGISTERED_TYPES.has_key(msg_type_name)

def get_registered(msg_type_name, default_package=None):
    """
    @param msg_type_name: name of message type
    @type  msg_type_name: str
    @return: msg spec for msg type name
    @rtype: L{MsgSpec}
    """
    if msg_type_name in REGISTERED_TYPES:
        return REGISTERED_TYPES[msg_type_name]
    elif default_package:
        # if msg_type_name has no package specifier, try with default package resolution
        p, n = roslib.names.package_resource_name(msg_type_name)
        if not p:
            return REGISTERED_TYPES[roslib.names.resource_name(default_package, msg_type_name)]
    raise KeyError(msg_type_name)

def register(msg_type_name, msg_spec):
    """
    Load MsgSpec into the type dictionary
    
    @param msg_type_name: name of message type
    @type  msg_type_name: str
    @param msg_spec: spec to load
    @type  msg_spec: L{MsgSpec}
    """
    if VERBOSE:
        print "Register msg %s"%msg_type_name
    REGISTERED_TYPES[msg_type_name] = msg_spec

