# Very, very naive RE-based way for collecting declarations inside
# 'cdef extern from *' Cython blocks in in source files, and next
# generate compatibility headers for MPI-2 partially implemented or
# built, or MPI-1 implementations, perhaps providing a subset of MPI-2

from textwrap import dedent
from warnings import warn
import mpiregexes as Re

class Node(object):

    REGEX = None
    def match(self, line):
        m = self.REGEX.search(line)
        if m: return m.groups()
    match = classmethod(match)

    HEADER = None
    CONFIG = None
    MISSING = None

    MISSING_HEAD = """\
    #ifndef PyMPI_HAVE_%(name)s
    #undef  %(cname)s
    """
    MISSING_TAIL = """
    #endif

    """

    def init(self, name, **kargs):
        assert name is not None
        self.name = name
        self.__dict__.update(kargs)
    def header(self):
        line = dedent(self.HEADER) % vars(self)
        line = line.replace('\n', '')
        line = line.replace('  ', ' ')
        return line + '\n'
    def config(self):
        return dedent(self.CONFIG) % vars(self)
    def missing(self, guard=True):
        if guard:
            head = dedent(self.MISSING_HEAD)
            tail = dedent(self.MISSING_TAIL)
        else:
            head = '#undef  %(cname)s\n'
            tail = '\n\n'
        body = dedent(self.MISSING)
        return (head+body+tail) % vars(self)

class NodeType(Node):
    CONFIG = """\
    %(ctype)s v; %(ctype)s* p; (void)v; (void)p;"""

    def __init__(self, ctype):
        self.init(name=ctype,
                  cname=ctype,
                  ctype=ctype,)

class NodeStructType(NodeType):
    HEADER = """\
    typedef struct {%(cfields)s ...; } %(ctype)s;"""
    MISSING = """\
    typedef struct PyMPI_%(ctype)s {
    %(cfields)s
    } PyMPI_%(ctype)s;
    #define %(ctype)s PyMPI_%(ctype)s"""

    def __init__(self, ctype, cfields):
        super(NodeStructType, self).__init__(ctype)
        self.cfields = '\n'.join(['  %s %s;' % field
                                  for field in cfields])

class NodeFuncType(NodeType):
    HEADER = """\
    typedef %(crett)s (%(cname)s)(%(cargs)s);"""
    MISSING = """\
    typedef %(crett)s (MPIAPI PyMPI_%(cname)s)(%(cargs)s);
    #define %(cname)s PyMPI_%(cname)s"""

    def __init__(self, crett, cname, cargs, calias=None):
        self.init(name=cname,
                  cname=cname,
                  ctype=cname+'*',)
        self.crett = crett
        self.cargs = cargs or 'void'
        if calias is not None:
            self.MISSING = '#define %(cname)s %(calias)s'
            self.calias = calias

class NodeValue(Node):
    HEADER = """\
    const %(ctype)s %(cname)s;"""
    CONFIG = """\
    %(ctype)s v; v = %(cname)s; (void)v;"""
    MISSING = '#define %(cname)s (%(calias)s)'

    def __init__(self, ctype, cname, calias):
        self.init(name=cname,
                  cname=cname,
                  ctype=ctype,
                  calias=calias)
        if ctype.endswith('*'):
            ctype = ctype + ' const'
            self.HEADER = ctype + ' %(cname)s;'

class NodePtrVal(NodeValue):
    MISSING = '#define %(cname)s ((%(ctype)s)%(calias)s)'

def ctypefix(ct):
    ct = ct.strip()
    ct = ct.replace('[][3]',' (*)[3]')
    ct = ct.replace('[]','*')
    return ct

class NodeFuncProto(Node):
    HEADER = """\
    %(crett)s %(cname)s(%(cargs)s);"""
    CONFIG = """\
    %(crett)s v; v = %(cname)s(%(cargscall)s); (void)v;"""
    MISSING = ' '. join(['#define %(cname)s(%(cargsnamed)s)',
                        'PyMPI_UNAVAILABLE("%(name)s"%(comma)s%(cargsnamed)s)'])
    def __init__(self, crett, cname, cargs, calias=None):
        self.init(name=cname,
                  cname=cname)
        self.crett = crett
        self.cargs = cargs or 'void'
        if cargs == 'void': cargs = ''
        if cargs:
            cargs = cargs.split(',')
            if cargs[-1].strip() == '...':
                del cargs[-1]
        else:
            cargs = []
        self.cargstype = cargs
        nargs = len(cargs)
        if nargs: self.comma = ','
        else:     self.comma = ''
        cargscall = ['(%s)0' % ctypefix(a) for a in cargs]
        self.cargscall = ','.join(cargscall)
        cargsnamed = ['a%d' % (a+1) for a in range(nargs)]
        self.cargsnamed = ','.join(cargsnamed)
        if calias is not None:
            self.MISSING = '#define %(cname)s %(calias)s'
            self.calias = calias

class IntegralType(NodeType):
    REGEX = Re.INTEGRAL_TYPE
    HEADER = """\
    typedef %(cbase)s... %(ctype)s;"""
    MISSING = """\
    typedef %(ctdef)s PyMPI_%(ctype)s;
    #define %(ctype)s PyMPI_%(ctype)s"""
    def __init__(self, cbase, ctype, calias=None):
        super(IntegralType, self).__init__(ctype)
        self.cbase = cbase
        if calias is not None:
            self.ctdef = calias
        else:
            self.ctdef = cbase

class StructType(NodeStructType):
    REGEX = Re.STRUCT_TYPE
    def __init__(self, ctype, calias=None):
        cfields = []
        if ctype == 'MPI_Status':
            cnames = ['MPI_SOURCE', 'MPI_TAG', 'MPI_ERROR']
            cfields = list(zip(['int']*3, cnames))
        super(StructType, self).__init__(ctype, cfields)
        if calias is not None:
            self.MISSING = '#define %(cname)s %(calias)s'
            self.calias = calias

class OpaqueType(NodeType):
    REGEX = Re.OPAQUE_TYPE
    HEADER = """\
    typedef struct{...;} %(ctype)s;"""
    MISSING = """\
    typedef void *PyMPI_%(ctype)s;
    #define %(ctype)s PyMPI_%(ctype)s"""

class FunctionType(NodeFuncType):
    REGEX = Re.FUNCTION_TYPE

class EnumValue(NodeValue):
    REGEX = Re.ENUM_VALUE
    def __init__(self, cname, calias):
        self.init(name=cname,
                  cname=cname,
                  ctype='int',
                  calias=calias)

class HandleValue(NodeValue):
    REGEX = Re.HANDLE_VALUE
    MISSING = '#define %(cname)s ((%(ctype)s)%(calias)s)'

class BasicPtrVal(NodePtrVal):
    REGEX = Re.BASIC_PTRVAL

class IntegralPtrVal(NodePtrVal):
    REGEX = Re.INTEGRAL_PTRVAL

class StructPtrVal(NodePtrVal):
    REGEX = Re.STRUCT_PTRVAL

class FunctionPtrVal(NodePtrVal):
    REGEX = Re.FUNCT_PTRVAL

class FunctionProto(NodeFuncProto):
    REGEX = Re.FUNCTION_PROTO

class FunctionC2F(NodeFuncProto):
    REGEX = Re.FUNCTION_C2F
    MISSING = ' '.join(['#define %(cname)s(%(cargsnamed)s)',
                       '((%(crett)s)0)'])

class FunctionF2C(NodeFuncProto):
    REGEX = Re.FUNCTION_F2C
    MISSING = ' '.join(['#define %(cname)s(%(cargsnamed)s)',
                       '%(cretv)s'])
    def __init__(self, *a, **k):
        NodeFuncProto.__init__(self, *a, **k)
        self.cretv =  self.crett.upper() + '_NULL'

class Scanner(object):

    NODE_TYPES = [
        IntegralType,
        StructType, OpaqueType,
        HandleValue, EnumValue,
        BasicPtrVal,
        IntegralPtrVal, StructPtrVal,
        FunctionType, FunctionPtrVal,
        FunctionProto, FunctionC2F, FunctionF2C,
        ]

    def __init__(self):
        self.nodes = []
        self.nodemap = {}

    def parse_file(self, filename):
        with open(filename) as f:
            self.parse_lines(f)

    def parse_lines(self, lines):
        for line in lines:
            self.parse_line(line)

    def parse_line(self, line):
        if Re.IGNORE.match(line): return
        nodemap  = self.nodemap
        nodelist = self.nodes
        for nodetype in self.NODE_TYPES:
            args = nodetype.match(line)
            if args:
                node = nodetype(*args)
                assert node.name not in nodemap, node.name
                nodemap[node.name] = len(nodelist)
                nodelist.append(node)
                break
        if not args:
            warn('unmatched line:\n%s' % line)

    def __iter__(self):
        return iter(self.nodes)

    def __getitem__(self, name):
        return self.nodes[self.nodemap[name]]

    def dump_header_h(self, fileobj):
        if isinstance(fileobj, str):
            with open(fileobj, 'w') as f:
                self.dump_header_h(f)
            return
        for node in self:
            fileobj.write(node.header())

    CONFIG_HEAD = """\
    #ifndef PyMPI_CONFIG_H
    #define PyMPI_CONFIG_H

    """
    CONFIG_MACRO = 'PyMPI_HAVE_%s'
    CONFIG_TAIL = """\

    #endif /* !PyMPI_CONFIG_H */
    """
    def dump_config_h(self, fileobj, suite):
        if isinstance(fileobj, str):
            with open(fileobj, 'w') as f:
                self.dump_config_h(f, suite)
            return
        head  = dedent(self.CONFIG_HEAD)
        macro = dedent(self.CONFIG_MACRO)
        tail  = dedent(self.CONFIG_TAIL)
        fileobj.write(head)
        if suite is None:
            for node in self:
                line = '#undef %s\n' % ((macro % node.name))
                fileobj.write(line)
        else:
            for name, result in suite:
                assert name in self.nodemap
                if result:
                    line = '#define %s 1\n' % ((macro % name))
                else:
                    line = '#undef  %s\n' % ((macro % name))
                fileobj.write(line)
        fileobj.write(tail)

    MISSING_HEAD = """\
    #ifndef PyMPI_MISSING_H
    #define PyMPI_MISSING_H

    #ifndef PyMPI_UNUSED
    # if defined(__GNUC__)
    #   if !defined(__cplusplus) || (__GNUC__>3||(__GNUC__==3&&__GNUC_MINOR__>=4))
    #     define PyMPI_UNUSED __attribute__ ((__unused__))
    #   else
    #     define PyMPI_UNUSED
    #   endif
    # elif defined(__INTEL_COMPILER) || defined(__ICC)
    #   define PyMPI_UNUSED __attribute__ ((__unused__))
    # else
    #   define PyMPI_UNUSED
    # endif
    #endif

    #define PyMPI_ERR_UNAVAILABLE (-1431655766) /*0xaaaaaaaa*/

    static PyMPI_UNUSED
    int PyMPI_UNAVAILABLE(const char *name,...)
    { (void)name; return PyMPI_ERR_UNAVAILABLE; }

    """
    MISSING_TAIL = """\
    #endif /* !PyMPI_MISSING_H */
    """
    def dump_missing_h(self, fileobj, suite):
        if isinstance(fileobj, str):
            with open(fileobj, 'w') as f:
                self.dump_missing_h(f, suite)
            return
        head = dedent(self.MISSING_HEAD)
        tail = dedent(self.MISSING_TAIL)
        #
        fileobj.write(head)
        if suite is None:
            for node in self:
                fileobj.write(node.missing())
        else:
            for name, result in suite:
                node = self[name]
                if not result:
                    fileobj.write(node.missing())
        fileobj.write(tail)

# -----------------------------------------

if __name__ == '__main__':
    import sys, os
    sources = [os.path.join('src', 'mpi4py', 'libmpi.pxd')]
    log = lambda msg: sys.stderr.write(msg + '\n')
    scanner = Scanner()
    for filename in sources:
        log('parsing file %s' % filename)
        scanner.parse_file(filename)
    log('processed %d definitions' % len(scanner.nodes))

    config_h  = os.path.join('src', 'lib-mpi', 'config', 'config.h')
    log('writing file %s' % config_h)
    scanner.dump_config_h(config_h, None)

    missing_h = os.path.join('src', 'lib-mpi', 'missing.h')
    log('writing file %s' % missing_h)
    scanner.dump_missing_h(missing_h, None)

    #libmpi_h = os.path.join('.', 'libmpi.h')
    #log('writing file %s' % libmpi_h)
    #scanner.dump_header_h(libmpi_h)

# -----------------------------------------
