irc-bridge: bidirectional color translation

bold is supported, but italic/underline/strikethrough is not

to match irc semantics, this also makes boldness a toggle,
replacing the old enable-only behavior

unlike irc, resetting to default foreground/background
will always reset boldness as a side-effect

README.md

@@ -29,7 +29,8 @@ retr0chat is the lightweight, no-dependencies, runs-anywhere solution for when l
 
 ## compatibility
 
-* [1980: TVI 920C](https://a.ocv.me/pub/g/nerd-stuff/r0c-tvi-920c.jpg)
+* 1980: [TVI 920C](https://a.ocv.me/pub/g/nerd-stuff/r0c-tvi-920c.jpg)
+* 1987: [IBM 3151](https://a.ocv.me/pub/g/nerd-stuff/r0c-ibm-3151.jpg) (also [video](https://a.ocv.me/pub/g/nerd-stuff/r0c-ibm-3151.webm)), using gnu-screen to translate VT100 sequences
 
 ## features
 

r0c/irc.py

@@ -232,7 +232,8 @@ class IRC_Net(object):
                 return
 
             txt = mw[3][1:]
-            print("irc<%s #%s> [%s] %s" % (self.host, ch_name, nick, txt))
+            txt = Util.convert_color_codes(Util.color_from_irc(txt))
+            print("irc<%s #%s> [%s] %s\033[0m" % (self.host, ch_name, nick, txt))
             try:
                 nch = self.world.get_pub_chan(self.chans[ch_name].r0c_cname)
                 self.world.send_chan_msg(nick, nch, txt, False)

r0c/ivt100.py

@@ -2858,9 +2858,10 @@ class VT100_Client(object):
                                     Util.convert_color_codes(self.linebuf),
                                 )
                                 for ircb in nch.ircb:
+                                    t = Util.color_to_irc(self.linebuf)
                                     ircb.net.say(
                                         "PRIVMSG #%s :<%s> %s"
-                                        % (ircb.irc_cname, self.user.nick, self.linebuf)
+                                        % (ircb.irc_cname, self.user.nick, t)
                                     )
 
                             self.msg_hist_n = None

r0c/util.py

@@ -9,6 +9,7 @@ import struct
 import time
 import sys
 import os
+import re
 import platform
 import itertools
 from datetime import datetime
@@ -454,14 +455,17 @@ def convert_color_codes(txt, preview=False):
             txt = u"%sK%s" % (txt[:ofs], txt[resume_txt:])
 
     scan_from = 0
+    is_bold = False
     while txt:
         ofs = txt.find(u"\x02", scan_from)
         if ofs < 0:
             break
 
         scan_from = ofs + 1
-        txt = u"%s\033[1m%s%s" % (
+        is_bold = not is_bold
+        txt = u"%s\033[%dm%s%s" % (
             txt[:ofs],
+            1 if is_bold else 22,
             u"B" if preview else u"",
             txt[scan_from:],
         )
@@ -482,6 +486,108 @@ def convert_color_codes(txt, preview=False):
     return txt
 
 
+FG_TO_IRC = {}
+FG_FROM_IRC = {}
+for n, ch in enumerate(u"f0429153ba6ecd87"):
+    FG_FROM_IRC[n] = u"\x0b%s" % (ch,)
+    FG_TO_IRC[ch] = u"\x03%02d" % (n,)
+
+BG_TO_IRC = {}
+BG_FROM_IRC = {}
+for n, ch in enumerate(u"7042115332664507"):
+    BG_FROM_IRC[n] = u",%s" % (ch,)
+    BG_TO_IRC[ch] = u",%02d" % (n,)
+
+IRC_COLOR_RE = re.compile("^([0-9]{1,2})(,[0-9]{1,2})?")
+
+
+def color_to_irc(txt):
+    # mostly copy-pasted from `convert_color_codes`
+    foregrounds = FG_TO_IRC
+    backgrounds = BG_TO_IRC
+    scan_from = 0
+    while txt:
+        ofs = txt.find(u"\x0b", scan_from)
+        if ofs < 0:
+            break
+
+        scan_from = ofs + 1
+
+        fg = None
+        if len(txt) > ofs + 1:
+            fg = txt[ofs + 1]
+
+        bg = None
+        if len(txt) > ofs + 3 and txt[ofs + 2] == u",":
+            bg = txt[ofs + 3]
+
+        if fg in foregrounds:
+            fg = foregrounds[fg]
+        else:
+            fg = None
+            bg = None  # can't set bg without valid fg
+
+        if bg in backgrounds:
+            bg = backgrounds[bg]
+        else:
+            bg = None
+
+        resume_txt = ofs + 1
+        if fg:
+            resume_txt += 1
+            scan_from = len(fg) + 1
+        if bg:
+            resume_txt += 2
+            scan_from += len(bg)
+
+        if fg and bg:
+            txt = u"%s%s%s%s" % (txt[:ofs], fg, bg, txt[resume_txt:])
+        elif fg:
+            txt = u"%s%s%s" % (txt[:ofs], fg, txt[resume_txt:])
+        else:
+            txt = u"%s\x03%s" % (txt[:ofs], txt[resume_txt:])
+
+    # irc bold  == r0c, \x02
+    # irc reset == r0c, \x0f
+    return txt
+
+
+def color_from_irc(txt):
+    fgs = FG_FROM_IRC
+    bgs = BG_FROM_IRC
+    ptn = IRC_COLOR_RE
+    scan_from = 0
+    while txt:
+        ofs = txt.find(u"\x03", scan_from)
+        if ofs < 0:
+            break
+
+        fg = bg = ""
+        scan_from = ofs + 1
+        m = ptn.search(txt[scan_from : scan_from + 5])
+        if m:
+            i = int(m.group(1))
+            if i < 16:
+                fg = fgs[i]
+                if m.group(2):
+                    i = int(m.group(2)[1:])
+                    if i < 16:
+                        bg = bgs[i]
+
+                scan_from += len(m.group(0 if bg else 1))
+
+        if bg:
+            txt = u"%s%s%s%s" % (txt[:ofs], fg, bg, txt[scan_from:])
+        elif fg:
+            txt = u"%s%s%s" % (txt[:ofs], fg, txt[scan_from:])
+        else:
+            txt = u"%s\x0f%s" % (txt[:ofs], txt[scan_from:])
+            # no easy/cheap way to encode "keep boldness and reset color";
+            # `convert_color_codes` would then eat any following a..f
+
+    return txt
+
+
 """
 
 def visualize_all_unicode_codepoints_as_utf8():