#!/usr/bin/env python3
#
# Copyright 2020, Data61, CSIRO (ABN 41 687 119 230)
#
# SPDX-License-Identifier: BSD-2-Clause
#

from __future__ import print_function
import sys
import six
from functools import reduce

# We assume length tp > 0


def parse_type(tps):
    def helper(tps):
        tp = tps[0]
        rest = tps[1:]

        if tp == 'Word':
            return ('Word', rest[0]), rest[1:]

        elif tp == 'Ptr':
            tp2, rest = helper(rest)
            return ('Ptr', tp2), rest

        elif tp == 'Unit':
            return ('Unit',), rest

        elif tp == 'Array':
            tp2, rest = helper(rest)
            # arrays are Array ... sz
            return ('Array', tp2, rest[0]), rest[1:]

        else:
            return ('Base', tp), rest

    return helper(tps)[0]


def splitBy(f, xs):
    def fold(acc, v):
        if f(v):
            acc[0].append(acc[1])
            return (acc[0], [])
        else:
            acc[1].append(v)
            return acc

    return (reduce(fold, xs, ([], [])))[0]


def handle_one_struct(s):
    def hdl_fld(f):
        fl, tp = f.split(':')
        return (fl.lstrip(), parse_type(tp.split(' ')))

    name = s[0]
    return (name, map(hdl_fld, s[1:]))


def dict_from_list(ls):
    a = {}
    for k, v in ls:
        a[k] = v

    return a


def is_base(x):
    return (x[0] == 'Base')


def base_name(x):
    return x[1]

# This assumes that membership is a DAG which is the case in C
# We could memoize, doesn't seem worth it ...


def paths_to_type(mp, f, start):
    def handle_one(fld):
        name, tp = fld
        if f(tp):
            return [([start + '.' + name], tp)]
        elif is_base(tp):
            res = paths_to_type(mp, f, base_name(tp))
            # prepend paths by name (why no Cons in python? grrr)
            map(lambda x: (x[0].insert(0, name)), res)
            return res
        else:
            return []

    # init case
    start_tp = ('Base', start)
    if f(start_tp):
        return [([], start_tp)]
    else:
        res = map(handle_one, mp[start])
        return (reduce(lambda x, y: x + y, res))


def build_types(file):
    in_file = open(file, 'r')

    lines = map(lambda x: x.rstrip(), in_file.readlines())

    in_file.close()

    grps = splitBy(lambda x: x == '', lines)

    # the order information will be important if we want _CL for all types
    sts = dict_from_list(map(handle_one_struct, grps))

    return sts


def print_graph(filename, out_file):
    mp = build_types(filename)

    print('digraph types {', file=out_file)
    for k, flds in six.iteritems(mp):
        for fld, tp in flds:
            # if is_base(tp):
            print('\t "%s" -> "%s" [label="%s"]' % (k, base_name(tp), fld),
                  file=out_file)
    print('}', file=out_file)

# Toplevel


if __name__ == '__main__':
    print_graph('umm_types.txt', sys.stdout)