#!/usr/bin/env python3

# ---------------------- faust2atomsnippets -----------------------
# Usage: `faust2atomsnippets *.lib > faust-library.cson`
#
# Creates an atom snippets for each function in a library
# Assumes the same format than faust2md.
#
# The generated snippets file as the following structure:
#
# '.source.faust':
#       'noise':
#               'prefix': 'noise'
#               'body': 'no.noise'
#       ...
#
# The format of a title is :
#       //############# Title Name #################
#       //  markdown text....
#       //  markdown text....
#       //##########################################
#
# The format of a section is :
#       //============== Section Name ==============
#       //  markdown text....
#       //  markdown text....
#       //==========================================
#
# The format of a comment is :
#       //-------------- foo(x,y) ------------------
#       //  markdown text....
#       //  markdown text....
#       //------------------------------------------
# everything else is considered faust code.
# The translation is the following:
#   ## foo(x,y)
#       markdown text....
#       markdown text....
# --------------------------------------------------------


import sys
import re
import getopt


# Outdent a comment line by n characters in
# order to remove the prefix "//   "
def outdent(line, n):
    if len(line) <= n:
        return "\n"
    else:
        return line[n:]


# Match the 2-characters prefix of a library.
# We want to extract "no" from "...prefix is `no`..."
def matchPrefixName(line):
    return re.search(r'^.*prefix is .(..).*', line)


# Match the first line of a title
# of type "//#### Title ####
# at least 3 * are needed
def matchBeginTitle(line):
    return re.search(r'^\s*//#{3,}\s*([^#]+)#{3,}', line)


# Match the last line of a title
# of type "//#######"
# or a blank line
def matchEndTitle(line):
    return re.search(r'^\s*((//#{3,})|(\s*))$', line)


# Match the first line of a section
# of type "//==== Section ===="
# at least 3 = are needed
def matchBeginSection(line):
    return re.search(r'^\s*//={3,}\s*([^=]+)={3,}', line)


# Match the last line of a section
# of type "//======="
# or a blank line
def matchEndSection(line):
    return re.search(r'^\s*((//={3,})|(\s*))$', line)


# Match the first line of a comment
# of type "//--- foo(x,y) ----"
# at least 3 - are needed
def matchBeginComment(line):
    return re.search(r'^\s*//-{3,}\s*`([^-`]+)`-{3,}', line)


# Match the last line of a comment
# of type "//-----------------"
# or a blank line
def matchEndComment(line):
    return re.search(r'^\s*((//-{3,})|(\s*))$', line)


# Compute the indentation of a line,
# that is the position of the first word character
# after "//   "
def indentation(line):
    matchComment = re.search(r'(^\s*//\s*\w)', line)
    if matchComment:
        return len(matchComment.group(1))-1
    else:
        return 0


# Indicates if a line is a comment
def isComment(line):
    matchComment = re.search(r'^\s*//', line)
    if matchComment:
        return 1
    else:
        return 0


#
# THE PROGRAM STARTS HERE
#
tabsize = 4             # tabsize used for expanding tabs
mode = 0             # 0: in code; 1: in md-comment
idt = 0             # indentation retained to outdent comment lines
simplified = 0         # 0: full mode; 1: body only
libprefix = "xx"  #


# Analyze command line arguments
try:
    opts, args = getopt.getopt(sys.argv[1:], "st:cf")
    if not args:
        raise getopt.error("At least one file argument required")
except getopt.error as e:
    print(e.msg)
    print("usage: %s [-s][-t tabsize] file ..." % (sys.argv[0],))
    sys.exit(1)
for optname, optvalue in opts:
    if optname == '-t':
        tabsize = int(optvalue)
    if optname == '-s':
        simplified = 1

# Process all the files and print the documentation on the standard output
if simplified:
    sys.stdout.write("let gFaustLibSnippets = ")
    sep = '['
else:
    print("'.source.faust':")

for file in args:
    with open(file) as f:
        for text in f:
            line = text.expandtabs(tabsize)
            matchPrefix = matchPrefixName(line)
            if matchPrefix:
                libprefix = matchPrefix.group(1)
            if isComment(line) == 0:
                if mode == 1:
                    # we are closing a md-comment
                    mode = 0
            else:
                if mode == 0:     # we are in code
                    matchComment = matchBeginComment(line)
                    matchSection = matchBeginSection(line)
                    matchTitle = matchBeginTitle(line)
                    if matchComment:
                        foo = matchComment.group(1)
                        if simplified:
                            sys.stdout.write("%s '%s.%s'" % (sep,
                                                             libprefix,
                                                             foo))
                            sep = ','
                        else:
                            print("\t'%s':" % (foo,))
                            print("\t\t'prefix': '%s'" % (foo,))
                            print("\t\t'body': '%s.%s'" % (libprefix, foo))
                    if matchComment or matchSection or matchTitle:
                        mode = 1  # we just started a md-comment
                        idt = 0  # we have to measure the indentation
                else:
                    # we are in a md-comment
                    if idt == 0:
                        # we have to measure the indentation
                        idt = indentation(line)
                    # check end of md-comment
                    matchComment = matchEndComment(line)
                    matchSection = matchEndSection(line)
                    matchTitle = matchEndTitle(line)
                    if matchComment or matchSection or matchTitle:
                        # end of md-comment switch back to mode O
                        mode = 0

if simplified:
    print(" ];")
