Add b4 ty that aims to simplify common feedback

New experimental feature that aims to simplify a very common "thanks,
applied" kind of feedback often expected of maintainers. Still needs
documentation to explain its usage.

Signed-off-by: Konstantin Ryabitsev <konstantin@linuxfoundation.org>

5 files changed, 591 insertions, 21 deletions

diff --git a/b4/__init__.py b/b4/__init__.py
index d108b76..54cc42b 100644
--- a/b4/__init__.py
+++ b/b4/__init__.py
@@ -174,8 +174,8 @@ class LoreMailbox:
             chunks = line.split(':')
             projmap[chunks[0]] = chunks[1].strip()
 
-        allto = email.utils.getaddresses(patch.msg.get_all('to', []))
-        allto += email.utils.getaddresses(patch.msg.get_all('cc', []))
+        allto = email.utils.getaddresses([str(x) for x in patch.msg.get_all('to', [])])
+        allto += email.utils.getaddresses([str(x) for x in patch.msg.get_all('cc', [])])
         listarc = patch.msg.get_all('list-archive', [])
         for entry in allto:
             if entry[1] in projmap:
@@ -307,7 +307,6 @@ class LoreMailbox:
                 continue
             lmsg.load_hashes()
             if lmsg.attestation.attid in self.trailer_map:
-                logger.info('WOO: %s', str(self.trailer_map[lmsg.attestation.attid]))
                 lmsg.followup_trailers.update(self.trailer_map[lmsg.attestation.attid])
 
         return lser
@@ -442,7 +441,7 @@ class LoreSeries:
             return 'undefined'
 
         prefix = lmsg.date.strftime('%Y%m%d')
-        authorline = email.utils.getaddresses(lmsg.msg.get_all('from', []))[0]
+        authorline = email.utils.getaddresses([str(x) for x in lmsg.msg.get_all('from', [])])[0]
         if extended:
             local = authorline[1].split('@')[0]
             unsafe = '%s_%s_%s' % (prefix, local, lmsg.subject)
@@ -635,7 +634,7 @@ class LoreMessage:
         self.in_reply_to = LoreMessage.get_clean_msgid(self.msg, header='In-Reply-To')
 
         try:
-            fromdata = email.utils.getaddresses(self.msg.get_all('from', []))[0]
+            fromdata = email.utils.getaddresses([str(x) for x in self.msg.get_all('from', [])])[0]
             self.fromname = fromdata[0]
             self.fromemail = fromdata[1]
         except IndexError:
@@ -780,6 +779,9 @@ class LoreMessage:
 
     @staticmethod
     def clean_header(hdrval):
+        if hdrval is None:
+            return ''
+
         decoded = ''
         for hstr, hcs in email.header.decode_header(hdrval):
             if hcs is None:
@@ -1448,6 +1450,7 @@ def get_data_dir():
         datahome = os.path.join(str(Path.home()), '.local', 'share')
     datadir = os.path.join(datahome, 'b4')
     Path(datadir).mkdir(parents=True, exist_ok=True)
+    return datadir
 
 
 def get_cache_dir():
@@ -1650,3 +1653,23 @@ def git_format_patches(gitdir, start, end, reroll=None):
     gitargs += ['%s..%s' % (start, end)]
     ecode, out = git_run_command(gitdir, gitargs)
     return ecode, out
+
+
+def git_commit_exists(gitdir, commit_id):
+    gitargs = ['cat-file', '-e', commit_id]
+    ecode, out = git_run_command(gitdir, gitargs)
+    return ecode == 0
+
+
+def git_branch_contains(gitdir, commit_id):
+    gitargs = ['branch', '--format=%(refname:short)', '--contains', commit_id]
+    lines = git_get_command_lines(gitdir, gitargs)
+    return lines
+
+
+def format_addrs(pairs):
+    addrs = set()
+    for pair in pairs:
+        # Remove any quoted-printable header junk from the name
+        addrs.add(email.utils.formataddr((LoreMessage.clean_header(pair[0]), LoreMessage.clean_header(pair[1]))))
+    return ', '.join(addrs)
diff --git a/b4/command.py b/b4/command.py
index d465732..d195509 100644
--- a/b4/command.py
+++ b/b4/command.py
@@ -55,6 +55,11 @@ def cmd_pr(cmdargs):
     b4.pr.main(cmdargs)
 
 
+def cmd_ty(cmdargs):
+    import b4.ty
+    b4.ty.main(cmdargs)
+
+
 def cmd():
     parser = argparse.ArgumentParser(
         description='A tool to work with public-inbox patches',
@@ -133,6 +138,26 @@ def cmd():
                        help='Message ID to process, or pipe a raw message')
     sp_pr.set_defaults(func=cmd_pr)
 
+    # b4 ty
+    sp_ty = subparsers.add_parser('ty', help='Generate thanks email when something gets merged/applied')
+    sp_ty.add_argument('-g', '--gitdir', default=None,
+                       help='Operate on this git tree instead of current dir')
+    sp_ty.add_argument('-o', '--outdir', default='.',
+                       help='Write thanks files into this dir (default=.)')
+    sp_ty.add_argument('-l', '--list', action='store_true', default=False,
+                       help='List pull requests and patch series you have retrieved')
+    sp_ty.add_argument('-s', '--send', nargs='+',
+                       help='Generate thankyous for specified messages (use -l to get the list or "all")')
+    sp_ty.add_argument('-d', '--discard', nargs='+',
+                       help='Discard specified messages (use -l to get the list, or use "_all")')
+    sp_ty.add_argument('-a', '--auto', action='store_true', default=False,
+                       help='Use the Auto-Thankanator to figure out what got applied/merged')
+    sp_ty.add_argument('-b', '--branch', default=None,
+                       help='The branch to check against, instead of current (use with -a)')
+    sp_ty.add_argument('--since', default='1.week',
+                       help='The --since option to use when auto-matching patches (default=1.week)')
+    sp_ty.set_defaults(func=cmd_ty)
+
     cmdargs = parser.parse_args()
 
     logger.setLevel(logging.DEBUG)
diff --git a/b4/mbox.py b/b4/mbox.py
index 3b00fd8..b11d7d1 100644
--- a/b4/mbox.py
+++ b/b4/mbox.py
@@ -13,6 +13,7 @@ import email.message
 import email.utils
 import re
 import time
+import json
 
 import urllib.parse
 import xml.etree.ElementTree
@@ -135,10 +136,71 @@ def mbox_to_am(mboxfile, cmdargs):
         logger.critical('       git am %s', am_filename)
 
     am_mbx.close()
+    thanks_record_am(lser)
 
     return am_filename
 
 
+def thanks_record_am(lser):
+    if not lser.complete:
+        logger.debug('Incomplete series, not tracking for thanks')
+        return
+
+    # Are we tracking this already?
+    datadir = b4.get_data_dir()
+    slug = lser.get_slug(extended=True)
+    filename = '%s.am' % slug
+    # Check if we're tracking it already
+    for entry in os.listdir(datadir):
+        if entry == filename:
+            return
+
+    # Get patch-id of each patch in the series
+    gitargs = ['patch-id', '--stable']
+    patches = list()
+    for pmsg in lser.patches[1:]:
+        ecode, out = b4.git_run_command(None, gitargs, stdin=pmsg.body.encode('utf-8'))
+        if ecode > 0 or not len(out.strip()):
+            logger.debug('Could not get patch-id of %s', pmsg.full_subject)
+            return
+        chunks = out.split()
+        patches.append((pmsg.subject, chunks[0]))
+
+    lmsg = lser.patches[0]
+    if lmsg is None:
+        lmsg = lser.patches[1]
+
+    allto = email.utils.getaddresses([str(x) for x in lmsg.msg.get_all('to', [])])
+    allcc = email.utils.getaddresses([str(x) for x in lmsg.msg.get_all('cc', [])])
+    quotelines = list()
+    qcount = 0
+    for line in lmsg.body.split('\n'):
+        # Quote the first paragraph only and then [snip] if we quoted more than 5 lines
+        if qcount > 5 and (not len(line.strip()) or line.strip().find('---') == 0):
+            quotelines.append('> ')
+            quotelines.append('> [...]')
+            break
+        quotelines.append('> %s' % line.strip('\r\n'))
+        qcount += 1
+
+    out = {
+        'msgid': lmsg.msgid,
+        'subject': lmsg.full_subject,
+        'fromname': lmsg.fromname,
+        'fromemail': lmsg.fromemail,
+        'to': b4.format_addrs(allto),
+        'cc': b4.format_addrs(allcc),
+        'references': b4.LoreMessage.clean_header(lmsg.msg['References']),
+        'sentdate': b4.LoreMessage.clean_header(lmsg.msg['Date']),
+        'quote': '\n'.join(quotelines),
+        'patches': patches,
+    }
+    fullpath = os.path.join(datadir, filename)
+    with open(fullpath, 'w', encoding='utf-8') as fh:
+        json.dump(out, fh, ensure_ascii=False, indent=4)
+        logger.debug('Wrote %s for thanks tracking', filename)
+
+
 def am_mbox_to_quilt(am_mbx, q_dirname):
     if os.path.exists(q_dirname):
         logger.critical('ERROR: Directory %s exists, not saving quilt patches', q_dirname)
diff --git a/b4/pr.py b/b4/pr.py
index 7efd398..2215861 100644
--- a/b4/pr.py
+++ b/b4/pr.py
@@ -10,6 +10,7 @@ import sys
 import b4
 import re
 import mailbox
+import json
 
 from datetime import timedelta
 from tempfile import mkstemp
@@ -69,18 +70,6 @@ def git_get_commit_id_from_repo_ref(repo, ref):
     return commit_id
 
 
-def git_commit_exists(gitdir, commit_id):
-    gitargs = ['cat-file', '-e', commit_id]
-    ecode, out = b4.git_run_command(gitdir, gitargs)
-    return ecode == 0
-
-
-def git_branch_contains(gitdir, commit_id):
-    gitargs = ['branch', '--contains', commit_id]
-    lines = b4.git_get_command_lines(gitdir, gitargs)
-    return lines
-
-
 def parse_pr_data(msg):
     lmsg = b4.LoreMessage(msg)
     if lmsg.body is None:
@@ -168,7 +157,7 @@ def attest_fetch_head(gitdir, lmsg):
 
 def fetch_remote(gitdir, lmsg, branch=None):
     # Do we know anything about this base commit?
-    if lmsg.pr_base_commit and not git_commit_exists(gitdir, lmsg.pr_base_commit):
+    if lmsg.pr_base_commit and not b4.git_commit_exists(gitdir, lmsg.pr_base_commit):
         logger.critical('ERROR: git knows nothing about commit %s', lmsg.pr_base_commit)
         logger.critical('       Are you running inside a git checkout and is it up-to-date?')
         return 1
@@ -203,9 +192,45 @@ def fetch_remote(gitdir, lmsg, branch=None):
     else:
         logger.info('Successfully fetched into FETCH_HEAD')
 
+    thanks_record_pr(lmsg)
+
     return 0
 
 
+def thanks_record_pr(lmsg):
+    datadir = b4.get_data_dir()
+    # Check if we're tracking it already
+    filename = '%s.pr' % lmsg.pr_remote_tip_commit
+    for entry in os.listdir(datadir):
+        if entry == filename:
+            return
+    allto = utils.getaddresses([str(x) for x in lmsg.msg.get_all('to', [])])
+    allcc = utils.getaddresses([str(x) for x in lmsg.msg.get_all('cc', [])])
+    quotelines = list()
+    for line in lmsg.body.split('\n'):
+        if line.find('---') == 0:
+            break
+        quotelines.append('> %s' % line.strip('\r\n'))
+
+    out = {
+        'msgid': lmsg.msgid,
+        'subject': lmsg.full_subject,
+        'fromname': lmsg.fromname,
+        'fromemail': lmsg.fromemail,
+        'to': b4.format_addrs(allto),
+        'cc': b4.format_addrs(allcc),
+        'references': b4.LoreMessage.clean_header(lmsg.msg['References']),
+        'remote': lmsg.pr_repo,
+        'ref': lmsg.pr_ref,
+        'sentdate': b4.LoreMessage.clean_header(lmsg.msg['Date']),
+        'quote': '\n'.join(quotelines),
+    }
+    fullpath = os.path.join(datadir, filename)
+    with open(fullpath, 'w', encoding='utf-8') as fh:
+        json.dump(out, fh, ensure_ascii=False, indent=4)
+        logger.debug('Wrote %s for thanks tracking', filename)
+
+
 def explode(gitdir, lmsg, savefile):
     # We always fetch into FETCH_HEAD when exploding
     ecode = fetch_remote(gitdir, lmsg)
@@ -293,6 +318,8 @@ def explode(gitdir, lmsg, savefile):
 
 
 def main(cmdargs):
+    gitdir = cmdargs.gitdir
+
     msgid = b4.get_msgid(cmdargs)
     savefile = mkstemp()[1]
     mboxfile = b4.get_pi_thread_by_msgid(msgid, savefile)
@@ -315,7 +342,6 @@ def main(cmdargs):
         logger.critical('ERROR: Could not find pull request info in %s', msgid)
         sys.exit(1)
 
-    gitdir = cmdargs.gitdir
     if not lmsg.pr_tip_commit:
         lmsg.pr_tip_commit = lmsg.pr_remote_tip_commit
 
@@ -328,11 +354,11 @@ def main(cmdargs):
             sys.exit(1)
         explode(gitdir, lmsg, savefile)
 
-    exists = git_commit_exists(gitdir, lmsg.pr_tip_commit)
+    exists = b4.git_commit_exists(gitdir, lmsg.pr_tip_commit)
 
     if exists:
         # Is it in any branch, or just flapping in the wind?
-        branches = git_branch_contains(gitdir, lmsg.pr_tip_commit)
+        branches = b4.git_branch_contains(gitdir, lmsg.pr_tip_commit)
         if len(branches):
             logger.info('Pull request tip commit exists in the following branches:')
             for branch in branches:
diff --git a/b4/ty.py b/b4/ty.py
new file mode 100644
index 0000000..245525a
--- /dev/null
+++ b/b4/ty.py
@@ -0,0 +1,434 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright (C) 2020 by the Linux Foundation
+#
+__author__ = 'Konstantin Ryabitsev <konstantin@linuxfoundation.org>'
+
+import os
+import sys
+import b4
+import re
+import email
+import email.message
+import json
+
+from string import Template
+from email import utils
+from pathlib import Path
+
+logger = b4.logger
+
+DEFAULT_PR_TEMPLATE = """
+On ${sentdate} ${fromname} wrote:
+${quote}
+
+Merged, thanks!
+
+Best regards,
+-- 
+${myname} <${myemail}>
+"""
+
+DEFAULT_AM_TEMPLATE = """
+On ${sentdate} ${fromname} wrote:
+${quote}
+
+Applied, thanks!
+
+Best regards,
+-- 
+${myname} <${myemail}>
+"""
+
+# Used to track commits created by current user
+MY_COMMITS = None
+
+
+def git_get_merge_id(gitdir, commit_id):
+    # get merge commit id
+    args = ['rev-list', '%s..' % commit_id, '--ancestry-path']
+    lines = b4.git_get_command_lines(gitdir, args)
+    if not len(lines):
+        return None
+    return lines[-1]
+
+
+def git_get_rev_diff(gitdir, rev):
+    args = ['diff', '%s~..%s' % (rev, rev)]
+    return b4.git_run_command(gitdir, args)
+
+
+def make_reply(reply_template, jsondata):
+    body = Template(reply_template).safe_substitute(jsondata)
+    # Conform to email standards
+    body = body.replace('\n', '\r\n')
+    msg = email.message_from_string(body)
+    msg['From'] = '%s <%s>' % (jsondata['myname'], jsondata['myemail'])
+    allto = utils.getaddresses([jsondata['to']])
+    allcc = utils.getaddresses([jsondata['cc']])
+    # Remove ourselves and original sender from allto or allcc
+    for entry in list(allto):
+        if entry[1] == jsondata['myemail'] or entry[1] == jsondata['fromemail']:
+            allto.remove(entry)
+    for entry in list(allcc):
+        if entry[1] == jsondata['myemail'] or entry[1] == jsondata['fromemail']:
+            allcc.remove(entry)
+
+    # Add original sender to the To
+    allto.append((jsondata['fromname'], jsondata['fromemail']))
+
+    msg['To'] = b4.format_addrs(allto)
+    msg['Cc'] = b4.format_addrs(allcc)
+    msg['In-Reply-To'] = '<%s>' % jsondata['msgid']
+    if len(jsondata['references']):
+        msg['References'] = '%s <%s>' % (jsondata['references'], jsondata['msgid'])
+    else:
+        msg['References'] = '<%s>' % jsondata['msgid']
+
+    if jsondata['subject'].find('Re: ') < 0:
+        msg['Subject'] = 'Re: %s' % jsondata['subject']
+    else:
+        msg['Subject'] = jsondata['subject']
+
+    mydomain = jsondata['myemail'].split('@')[1]
+    msg['Message-Id'] = email.utils.make_msgid(idstring='b4-ty', domain=mydomain)
+    return msg
+
+
+def auto_locate_pr(gitdir, jsondata, branch):
+    pr_commit_id = jsondata['pr_commit_id']
+    logger.debug('Checking %s', jsondata['pr_commit_id'])
+    if not b4.git_commit_exists(gitdir, pr_commit_id):
+        return None
+
+    onbranches = b4.git_branch_contains(gitdir, pr_commit_id)
+    if not len(onbranches):
+        logger.debug('%s is not on any branches', pr_commit_id)
+        return None
+    if branch not in onbranches:
+        logger.debug('%s is not on branch %s', pr_commit_id, branch)
+        return None
+
+    # Get the merge commit
+    merge_commit_id = git_get_merge_id(gitdir, pr_commit_id)
+    if not merge_commit_id:
+        logger.debug('Could not get a merge commit-id for %s', pr_commit_id)
+        return None
+
+    # Check that we are the author of the merge commit
+    gitargs = ['show', '--format=%ae', merge_commit_id]
+    out = b4.git_get_command_lines(gitdir, gitargs)
+    if not out:
+        logger.debug('Could not get merge commit author for %s', pr_commit_id)
+        return None
+
+    usercfg = b4.get_user_config()
+    if usercfg['email'] not in out:
+        logger.debug('Merged by a different author, ignoring %s', pr_commit_id)
+        logger.debug('Author: %s', out[0])
+        return None
+
+    return merge_commit_id
+
+
+def get_all_commits(gitdir, branch, since='1.week', committer=None):
+    global MY_COMMITS
+    if MY_COMMITS is not None:
+        return MY_COMMITS
+
+    MY_COMMITS = dict()
+    if committer is None:
+        usercfg = b4.get_user_config()
+        committer = usercfg['email']
+
+    gitargs = ['log', '--committer', committer, '--no-abbrev', '--oneline', '--since', since, branch]
+    lines = b4.git_get_command_lines(gitdir, gitargs)
+    if not len(lines):
+        logger.debug('No new commits from the current user --since=%s', since)
+        return MY_COMMITS
+
+    logger.info('Found %s of your comits since %s', len(lines), since)
+    logger.info('Calculating patch-ids, may take a moment...')
+    # Get patch-id of each commit
+    for line in lines:
+        commit_id, subject = line.split(maxsplit=1)
+        ecode, out = git_get_rev_diff(gitdir, commit_id)
+        gitargs = ['patch-id', '--stable']
+        ecode, out = b4.git_run_command(None, gitargs, stdin=out.encode('utf-8'))
+        chunks = out.split()
+        MY_COMMITS[chunks[0]] = (commit_id, subject)
+
+    return MY_COMMITS
+
+
+def auto_locate_series(gitdir, jsondata, branch, since='1.week'):
+    commits = get_all_commits(gitdir, branch, since)
+
+    patchids = set(commits.keys())
+    # We need to find all of them in the commits
+    found = list()
+    for patch in jsondata['patches']:
+        if patch[1] in patchids:
+            logger.debug('Found: %s', patch[0])
+            found.append(commits[patch[1]])
+
+    if len(found) == len(jsondata['patches']):
+        return found
+
+    return None
+
+
+def generate_pr_thanks(jsondata):
+    config = b4.get_main_config()
+    thanks_template = DEFAULT_PR_TEMPLATE
+    if 'thanks-pr-template' in config:
+        # Try to load this template instead
+        try:
+            with open(config['thanks-pr-template'], 'r', encoding='utf-8') as fh:
+                thanks_template = fh.read()
+        except FileNotFoundError:
+            logger.critical('ERROR: thanks-pr-template says to use %s, but it does not exist',
+                            config['thanks-pr-template'])
+            sys.exit(2)
+
+    msg = make_reply(thanks_template, jsondata)
+    return msg
+
+
+def generate_am_thanks(jsondata):
+    config = b4.get_main_config()
+    thanks_template = DEFAULT_AM_TEMPLATE
+    if 'thanks-am-template' in config:
+        # Try to load this template instead
+        try:
+            with open(config['thanks-am-template'], 'r', encoding='utf-8') as fh:
+                thanks_template = fh.read()
+        except FileNotFoundError:
+            logger.critical('ERROR: thanks-am-template says to use %s, but it does not exist',
+                            config['thanks-am-template'])
+            sys.exit(2)
+
+    msg = make_reply(thanks_template, jsondata)
+    return msg
+
+
+def auto_thankanator(cmdargs):
+    gitdir = cmdargs.gitdir
+    if not cmdargs.branch:
+        # Find out our current branch
+        gitargs = ['branch', '--show-current']
+        ecode, out = b4.git_run_command(gitdir, gitargs)
+        if ecode > 0:
+            logger.critical('Not able to get current branch (git branch --show-current)')
+            sys.exit(1)
+        wantbranch = out.strip()
+    else:
+        # Make sure it's a real branch
+        gitargs = ['branch', '--format=%(refname:short)', '--list']
+        lines = b4.git_get_command_lines(gitdir, gitargs)
+        if not len(lines):
+            logger.critical('Not able to get a list of branches (git branch --list)')
+            sys.exit(1)
+        if cmdargs.branch not in lines:
+            logger.critical('Requested branch %s not found in git branch --list', cmdargs.branch)
+            sys.exit(1)
+        wantbranch = cmdargs.branch
+
+    logger.info('Auto-thankinating using branch %s', wantbranch)
+    tracked = list_tracked()
+    if not len(tracked):
+        logger.info('Nothing to do')
+        sys.exit(0)
+
+    applied = list()
+    for jsondata in tracked:
+        if 'pr_commit_id' in jsondata:
+            # this is a pull request
+            merge_commit_id = auto_locate_pr(gitdir, jsondata, wantbranch)
+            if merge_commit_id is None:
+                continue
+            jsondata['merge_commit_id'] = merge_commit_id
+        else:
+            # This is a patch series
+            patches = auto_locate_series(gitdir, jsondata, wantbranch, since=cmdargs.since)
+            if patches is None:
+                continue
+        applied.append(jsondata)
+        logger.info('  Located: %s', jsondata['subject'])
+
+    if not len(applied):
+        logger.info('Nothing to do')
+        sys.exit(0)
+
+    logger.info('---')
+    send_messages(applied, cmdargs.outdir)
+    sys.exit(0)
+
+
+def send_messages(listing, outdir):
+    # Not really sending, but writing them out to be sent on your own
+    # We'll probably gain ability to send these once the feature is
+    # more mature and we're less likely to mess things up
+    datadir = b4.get_data_dir()
+    logger.info('Generating %s thank-you letters', len(listing))
+    # Check if the outdir exists and if it has any .thanks files in it
+    if not os.path.exists(outdir):
+        os.mkdir(outdir)
+
+    for jsondata in listing:
+        slug_from = re.sub(r'\W', '_', jsondata['fromemail'])
+        slug_subj = re.sub(r'\W', '_', jsondata['subject'])
+        slug = '%s_%s' % (slug_from.lower(), slug_subj.lower())
+        slug = re.sub(r'_+', '_', slug)
+        if 'pr_commit_id' in jsondata:
+            # This is a pull request
+            msg = generate_pr_thanks(jsondata)
+        else:
+            # This is a patch series
+            msg = generate_am_thanks(jsondata)
+
+        outfile = os.path.join(outdir, '%s.thanks' % slug)
+        logger.info('  Writing: %s', outfile)
+        with open(outfile, 'wb') as fh:
+            fh.write(msg.as_bytes(policy=b4.emlpolicy))
+        logger.debug('Cleaning up: %s', jsondata['trackfile'])
+        fullpath = os.path.join(datadir, jsondata['trackfile'])
+        os.rename(fullpath, '%s.sent' % fullpath)
+    logger.info('---')
+    logger.info('You can now run:')
+    logger.info('  git send-email %s/*.thanks', outdir)
+
+
+def list_tracked():
+    # find all tracked bits
+    tracked = list()
+    datadir = b4.get_data_dir()
+    paths = sorted(Path(datadir).iterdir(), key=os.path.getmtime)
+    usercfg = b4.get_user_config()
+    for fullpath in paths:
+        if fullpath.suffix not in ('.pr', '.am'):
+            continue
+        with fullpath.open('r', encoding='utf-8') as fh:
+            jsondata = json.load(fh)
+            jsondata['myname'] = usercfg['name']
+            jsondata['myemail'] = usercfg['email']
+            jsondata['trackfile'] = fullpath.name
+            if fullpath.suffix == '.pr':
+                jsondata['pr_commit_id'] = fullpath.stem
+        tracked.append(jsondata)
+    return tracked
+
+
+def write_tracked(tracked):
+    counter = 1
+    config = b4.get_main_config()
+    logger.info('Currently tracking:')
+    for entry in tracked:
+        logger.info('%3d: %s', counter, entry['subject'])
+        logger.info('       From: %s <%s>', entry['fromname'], entry['fromemail'])
+        logger.info('       Date: %s', entry['sentdate'])
+        logger.info('       Link: %s', config['linkmask'] % entry['msgid'])
+        counter += 1
+
+
+def send_selected(cmdargs):
+    tracked = list_tracked()
+    if not len(tracked):
+        logger.info('Nothing to do')
+        sys.exit(0)
+
+    listing = list()
+    for num in cmdargs.send:
+        try:
+            index = int(num) - 1
+            listing.append(tracked[index])
+        except ValueError:
+            logger.critical('Please provide the number of the message')
+            logger.info('---')
+            write_tracked(tracked)
+            sys.exit(1)
+        except IndexError:
+            logger.critical('Invalid index: %s', num)
+            logger.info('---')
+            write_tracked(tracked)
+            sys.exit(1)
+    if not len(listing):
+        logger.info('Nothing to do')
+        sys.exit(0)
+
+    send_messages(listing, cmdargs.outdir)
+
+
+def discard_selected(cmdargs):
+    tracked = list_tracked()
+    if not len(tracked):
+        logger.info('Nothing to do')
+        sys.exit(0)
+
+    if '_all' in cmdargs.discard:
+        listing = tracked
+    else:
+        listing = list()
+        for num in cmdargs.discard:
+            try:
+                index = int(num) - 1
+                listing.append(tracked[index])
+            except ValueError:
+                logger.critical('Please provide the number of the message')
+                logger.info('---')
+                write_tracked(tracked)
+                sys.exit(1)
+            except IndexError:
+                logger.critical('Invalid index: %s', num)
+                logger.info('---')
+                write_tracked(tracked)
+                sys.exit(1)
+
+    if not len(listing):
+        logger.info('Nothing to do')
+        sys.exit(0)
+
+    datadir = b4.get_data_dir()
+    logger.info('Discarding %s messages', len(listing))
+    for jsondata in listing:
+        fullpath = os.path.join(datadir, jsondata['trackfile'])
+        os.rename(fullpath, '%s.discarded' % fullpath)
+        logger.info('  Discarded: %s', jsondata['subject'])
+
+    sys.exit(0)
+
+
+def check_stale_thanks(outdir):
+    if os.path.exists(outdir):
+        for entry in Path(outdir).iterdir():
+            if entry.suffix == '.thanks':
+                logger.critical('ERROR: Found existing .thanks files in: %s', outdir)
+                logger.critical('       Please send them first (or delete if already sent).')
+                logger.critical('       Refusing to run to avoid potential confusion.')
+                sys.exit(1)
+
+
+def main(cmdargs):
+    usercfg = b4.get_user_config()
+    if 'email' not in usercfg:
+        logger.critical('Please set user.email in gitconfig to use this feature.')
+        sys.exit(1)
+
+    if cmdargs.auto:
+        auto_thankanator(cmdargs)
+        check_stale_thanks(cmdargs.outdir)
+    elif cmdargs.send:
+        send_selected(cmdargs)
+        check_stale_thanks(cmdargs.outdir)
+    elif cmdargs.discard:
+        discard_selected(cmdargs)
+    else:
+        tracked = list_tracked()
+        if not len(tracked):
+            logger.info('No thanks necessary.')
+            sys.exit(0)
+        write_tracked(tracked)
+        logger.info('---')
+        logger.info('You can send them using:')
+        logger.info('  b4 ty -s 1 [2 3 ...]')