#!/usr/bin/python
# -*- python -*-
"""
NAME
	%(program)s - look for SVN commits that are ready to merge

SYNOPSIS
	%(program)s [OPTIONS] ARGS

DESCRIPTION
	%(program)s looks in the SVN log for commits which are marked with the
        phrase 'Commit ready for merge', and compares the resulting list with
        the 'svn:mergeinfo' property on the current directory, in order to
        work out which (if any) commits are ready to merge, but not yet
        merged.  The command requires (and checks) that it's running in a
        directory named 'trunk', and requires that to be an SVN working copy.

        The files (in the top directory of the working copy) 'ready-for-merge'
        and 'hold-for-merge' are also consulted for additions and exceptions to
        the merge list.

        A list of commit date, committer, and branch@revision for each commit
        which is marked ready for merge, but not yet merged, is then written
        to standard out.

%(options)s

AUTHOR
	Written by Henrik Levkowetz, <henrik@tools.ietf.org>

COPYRIGHT
	Copyright 2014 Henrik Levkowetz

	This program is free software; you can redistribute it and/or modify
	it under the terms of the Simplified BSD license as published by the
        Open Source Initiative at http://opensource.org/licenses/BSD-2-Clause.

"""
from __future__ import print_function

import sys, os.path, getopt, re
import debug

version = "0.20"
program = os.path.basename(sys.argv[0])
progdir = os.path.dirname(sys.argv[0])

# ----------------------------------------------------------------------
# Parse options

options = ""
for line in re.findall("\n +(if|elif) +opt in \[(.+)\]:\s+#(.+)\n", open(sys.argv[0]).read()):
    if not options:
        options += "OPTIONS\n"
    options += "        %-16s %s\n" % (line[1].replace('"', ''), line[2])
options = options.strip()

# with ' < 1:' on the next line, this is a no-op:
if len(sys.argv) < 1:
    print(__doc__ % locals())
    sys.exit(1)

try:
    opts, files = getopt.gnu_getopt(sys.argv[1:], "hvV", ["help", "version","verbose",])
except Exception, e:
    print( "%s: %s" % (program, e))
    sys.exit(1)

# ----------------------------------------------------------------------
# Handle options

# set default values, if any
opt_verbose = 0

# handle individual options
for opt, value in opts:
    if   opt in ["-h", "--help"]: # Output this help, then exit
        print( __doc__ % locals() )
        sys.exit(1)
    elif opt in ["-v", "--version"]: # Output version information, then exit
        print( program, version )
        sys.exit(0)
    elif opt in ["-V", "--verbose"]: # Output version information, then exit
        opt_verbose += 1

# ----------------------------------------------------------------------
def say(s):
    sys.stderr.write("%s\n" % (s))

# ----------------------------------------------------------------------
def note(s):
    if opt_verbose:
        sys.stderr.write("%s\n" % (s))

# ----------------------------------------------------------------------
def die(s, error=1):
    sys.stderr.write("\n%s: Error: %s\n\n" % (program, s))
    sys.exit(error)

# ----------------------------------------------------------------------
# The program itself    

import os
import json

cwd = os.getcwd()

if cwd.split(os.path.sep)[-1] != 'trunk':
    die("Expected to run this operation in trunk, but the current\ndirectory is '%s'" % cwd)

# ----------------------------------------------------------------------
# Some utility functions

def pipe(cmd, inp=None):
    import shlex
    from subprocess import Popen, PIPE
    args = shlex.split(cmd)
    bufsize = 4096
    stdin = PIPE if inp else None
    pipe = Popen(args, stdin=stdin, stdout=PIPE, stderr=PIPE, bufsize=bufsize)
    out, err = pipe.communicate(inp)
    code = pipe.returncode
    if code != 0:
        raise OSError(err)
    return out

def split_loginfo(line):
    parts = line.split()
    rev = parts[0][1:]
    who = parts[2]
    date = parts[4]
    time = parts[5]
    when = "%s_%s" % (date, time)
    return rev, who, when

# ----------------------------------------------------------------------

# Get repository information
svn_info = {}
for line in pipe('svn info .').splitlines():
    if line:
        key, value = line.strip().split(':', 1)
        svn_info[key] = value.strip()

repo = svn_info["Repository Root"]
head = int(svn_info['Revision'])

# Get current mergeinfo from cache and svn
cachefn = os.path.join(os.environ.get('HOME', '.'), '.mergeinfo')

if os.path.exists(cachefn):
    with open(cachefn, "r") as file:
        cache = json.load(file)
else:
    sys.stderr.write("No merge info cache file found -- will have to extract all information from SVN.\n"+
        "This may take some time.\n\n")
    cache = {}
mergeinfo = cache[repo] if repo in cache else {}

merged_revs = {}
write_cache = False
for line in pipe('svn propget svn:mergeinfo .').splitlines():
    if line in mergeinfo:
        merged = mergeinfo[line]
    else:
        merged = {}
        branch, revs = line.strip().split(':',1)
        for part in revs.split(','):
            if '-' in part:
                beg, end = part.split('-')
                try:
                    commit_log = pipe('svn log -v -r %s:%s %s%s' % (beg, end, repo, branch))
                    for logline in commit_log.splitlines():
                        if re.search('^r[0-9]+ ', logline):
                            rev, who, when = split_loginfo(logline)
                            merged[rev] = branch[1:]
                            write_cache = True
                except OSError:
                    pass
            else:
                merged[part] = branch[1:]
                write_cache = True
        mergeinfo[line] = merged
    merged_revs.update(merged)

if write_cache:
    cache[repo] = mergeinfo
    with open(cachefn, "w") as file:
        json.dump(cache, file, indent=2, sort_keys=True)

def get_list(repo, filename):
    list = []
    note("Reading list from '%s'" % filename)
    with open(filename) as file:
        for line in file:
            line = line.strip()
            if line.startswith('#') or line == "":
                continue
            try:
                note("   '%s'" % line)
                changeset = line.split()[0]
                branch, rev = changeset.split('@')
                if branch.startswith('/'):
                    branch = branch[1:]
                if not (rev in merged_revs and branch == merged_revs[rev]):
                    list += [(rev, repo, branch),]
                #elif rev in merged_revs and not branch == merged_revs[rev]:
                #    sys.stderr.write('Rev %s: %s != %s' % (rev, branch, merged_revs[rev]))                
                else:
                    #sys.stderr.write('Already merged: merged_revs[%s]: %s\n' % (rev, merged_revs[rev]))
                    pass
            except ValueError as e:
                sys.stderr.write("Bad changeset specification in %s: '%s': %s\n" % (file.name, changeset, e))
    return list

def get_ready_commits(repo, tree):
    list = []
    note("Getting ready commits from '%s'" % tree)
    cmd = 'svn log -v -r %s:HEAD %s/%s/' % ((head-500), repo, tree)
    if opt_verbose > 1:
        note("Running '%s' ..." % cmd)
    commit_log = pipe(cmd)
    for line in commit_log.splitlines():
        if re.search('^r[0-9]+ ', line):
            rev, who, when = split_loginfo(line)
            branch = None
            continue
        if (line.startswith('   M') or line.startswith('   A') or line.startswith('   D')) and branch == None:
            type, path = line[:4], line[5:]
            branch = '/'.join(path.split('/')[1:4])
        elif re.search("(?i)((commit|branch) ready (for|to) merge)", line):
            if not (rev in merged_revs and branch == merged_revs[rev]):
                note("   %s  %s: %s@%s" % (when, who, branch, rev))
                list += [(rev, repo, branch),]
            elif rev in merged_revs and not branch == merged_revs[rev]:
                sys.stderr.write('Rev %s: %s != %s' % (rev, branch, merged_revs[rev]))                
            else:
                pass
        else:
            pass
            
    return list
    
ready  = get_list(repo, 'ready-for-merge')
hold   = get_list(repo, 'hold-for-merge')
ready += get_ready_commits(repo, 'personal')
ready += get_ready_commits(repo, 'branch/amsl')

ready_commits = {}
for entry in ready:
    rev, repo, branch = entry
    cmd = 'svn log -v -r %s %s/%s/' % (rev, repo, branch)
    if opt_verbose > 1:
        note("Running '%s' ..." % cmd)
    loginfo = pipe(cmd).splitlines()
    try:
        rev, who, when = split_loginfo(loginfo[1])
    except IndexError:
        die("Wrong changeset version in %s@%s ?" % (branch, rev))
    for line in loginfo[3:]:
        type, path = line[:4], line[5:]
        if 'M' in type or 'A' in type or 'D' in type:
            break
    merge_path = os.path.join(*path.split(os.path.sep)[:4])
    if not (rev, repo, merge_path) in hold:
        ready_commits[when] = "%s  %-24s %s@%s" % (when, who+":", merge_path, rev)

keys = ready_commits.keys()
keys.sort()
for key in keys:
    print(ready_commits[key])

print("\n%s pending merges" % len(keys))