#!/usr/bin/env python

# This is ~/.message-formatter - a mutt display filter
# to format an email message for the screen width
# (C) Silas S. Brown 2007,2010,2012,2020,2022.  Version 1.43.

# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
# 
#     http://www.apache.org/licenses/LICENSE-2.0
# 
# 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 License for the specific language governing permissions and
# limitations under the License.

# Where to find history:
# on GitHub at https://github.com/ssb22/config
# and on GitLab at https://gitlab.com/ssb22/config
# and on BitBucket https://bitbucket.org/ssb22/config
# and at https://gitlab.developers.cam.ac.uk/ssb22/config
# and in China: https://gitee.com/ssb22/config

import sys,os,subprocess
try: width = sys.argv[1]
except: width = "48" # probably means some script without terminal ran mutt in background
quote_level = -1 # in header
quote_prefix = []
para = [] ; para_start = 1
try: import textwrap
except: textwrap = None

def output_para(para,quote_prefix):
  fmt = "fmt -"+width ; para = ''.join(para)
  if len(para) > 3000: # don't try to optimise, if the paragraph is too big (especially if contains CJK)
    if textwrap:
      for l in textwrap.wrap(para,int(width)):
        p=''.join(quote_prefix)+l
        if type(p)==type(u"") and not type("")==type(u""): p=p.encode("utf-8")
        print(p)
      return
    fmt += " -s"
  if quote_prefix: cmd = fmt+" '--prefix="+''.join(quote_prefix)+"'"
  else: cmd = fmt
  sp=subprocess.Popen(cmd,shell=True,stdin=subprocess.PIPE,stdout=subprocess.PIPE,stderr=subprocess.PIPE,universal_newlines=True)
  if type(u"")==type(""): out,err = sp.communicate(''.join(para)) # Python 3
  else: out,err = sp.communicate(''.join(para).encode('utf-8')) # Python 2
  sys.stdout.write(out)

while 1:
  r = sys.stdin.readline().replace("\r\n","\n")
  if not r: break
  try: r = r.decode('utf-8') # for Python 2
  except: pass # Python 3 already decoded, or not UTF-8
  if r=="\n" or r=="-- \n": quote_level,para_start = 0,1
  new_quote_level = 0 ; new_quote_prefix = []
  # Figure out the quote type for just this line:
  for c in r:
    if c in "|>:}#": new_quote_level += 1
    elif not c==' ': break
    new_quote_prefix.append(c)
  if not new_quote_level==quote_level: para_start=1
  if para_start and para:
    # Start of new paragraph, so format the previous one if any
    output_para(para,quote_prefix)
    quote_prefix = new_quote_prefix ; new_quote_prefix = []
    para = []
  para_start = 0
  if quote_level==-1 or r=="-- \n" or r=="\n":
    if type(u"")==type(""): sys.stdout.write(r) # Python 3
    elif type(r)==type(u""): sys.stdout.write(r.encode('utf-8')) # Python 2
    else: sys.stdout.write(repr(r)+'\n') # Python 2 + wasn't valid UTF-8
  else: para.append(r)
  if not quote_level==-1: quote_level = new_quote_level
if para: output_para(para,quote_prefix)