#!/usr/bin/python
#
# p4-fast-export.py
#
# Author: Simon Hausmann <hausmann@kde.org>
# License: MIT <http://www.opensource.org/licenses/mit-license.php>
#
# TODO:
#       - support integrations (at least p4i)
#       - support incremental imports
#       - create tags
#       - instead of reading all files into a variable try to pipe from
#       - support p4 submit (hah!)
#       - don't hardcode the import to master
#
import os, string, sys, time
import marshal, popen2

if len(sys.argv) != 2:
    print "usage: %s //depot/path[@revRange]" % sys.argv[0]
    print "\n    example:"
    print "    %s //depot/my/project/ -- to import everything"
    print "    %s //depot/my/project/@1,6 -- to import only from revision 1 to 6"
    print ""
    print "    (a ... is not needed in the path p4 specification, it's added implicitly)"
    print ""
    sys.exit(1)

prefix = sys.argv[1]
changeRange = ""
try:
    atIdx = prefix.index("@")
    changeRange = prefix[atIdx:]
    prefix = prefix[0:atIdx]
except ValueError:
    changeRange = ""

if not prefix.endswith("/"):
    prefix += "/"

def p4Cmd(cmd):
    pipe = os.popen("p4 -G %s" % cmd, "rb")
    result = {}
    try:
        while True:
            entry = marshal.load(pipe)
            result.update(entry)
    except EOFError:
        pass
    pipe.close()
    return result

def describe(change):
    output = os.popen("p4 describe %s" % change).readlines()

    firstLine = output[0]

    splitted = firstLine.split(" ")
    author = splitted[3]
    author = author[:author.find("@")]
    tm = time.strptime(splitted[5] + " " + splitted[6], "%Y/%m/%d %H:%M:%S ")
    epoch = int(time.mktime(tm))

    filesSection = 0
    try:
        filesSection = output.index("Affected files ...\n")
    except ValueError:
        sys.stderr.write("Change %s doesn't seem to affect any files. Weird.\n" % change)
        return [], [], [], [], []

    differencesSection = 0
    try:
        differencesSection = output.index("Differences ...\n")
    except ValueError:
        sys.stderr.write("Change %s doesn't seem to have a differences section. Weird.\n" % change)
        return [], [], [], [], []

    log = output[2:filesSection - 1]

    lines = output[filesSection + 2:differencesSection - 1]

    changed = []
    removed = []

    for line in lines:
        # chop off "... " and trailing newline
        line = line[4:len(line) - 1]

        lastSpace = line.rfind(" ")
        if lastSpace == -1:
            sys.stderr.write("trouble parsing line %s, skipping!\n" % line)
            continue

        operation = line[lastSpace + 1:]
        path = line[:lastSpace]

        if operation == "delete":
            removed.append(path)
        else:
            changed.append(path)

    return author, log, epoch, changed, removed

def p4Stat(path):
    output = os.popen("p4 fstat -Ol \"%s\"" % path).readlines()
    fileSize = 0
    mode = 644
    for line in output:
        if line.startswith("... headType x"):
            mode = 755
        elif line.startswith("... fileSize "):
            fileSize = long(line[12:])
    return mode, fileSize

def stripRevision(path):
    hashPos = path.rindex("#")
    return path[:hashPos]

def getUserMap():
    users = {}
    output = os.popen("p4 users")
    for line in output:
        firstSpace = line.index(" ")
        secondSpace = line.index(" ", firstSpace + 1)
        key = line[:firstSpace]
        email = line[firstSpace + 1:secondSpace]
        openParenPos = line.index("(", secondSpace)
        closedParenPos = line.index(")", openParenPos)
        name = line[openParenPos + 1:closedParenPos]

        users[key] = name + " " + email

    return users

users = getUserMap()

output = os.popen("p4 changes %s...%s" % (prefix, changeRange)).readlines()

changes = []
for line in output:
    changeNum = line.split(" ")[1]
    changes.append(changeNum)

changes.reverse()

sys.stderr.write("\n")

tz = - time.timezone / 36

gitOutput, gitStream, gitError = popen2.popen3("git-fast-import")

cnt = 1
for change in changes:
    [ author, log, epoch, changedFiles, removedFiles ] = describe(change)
    sys.stdout.write("\rimporting revision %s (%s%%)" % (change, cnt * 100 / len(changes)))
    cnt = cnt + 1

    gitStream.write("commit refs/heads/master\n")
    if author in users:
        gitStream.write("committer %s %s %s\n" % (users[author], epoch, tz))
    else:
        gitStream.write("committer %s <a@b> %s %s\n" % (author, epoch, tz))
    gitStream.write("data <<EOT\n")
    for l in log:
        gitStream.write(l)
    gitStream.write("EOT\n\n")

    for f in changedFiles:
        if not f.startswith(prefix):
            sys.stderr.write("\nchanged files: ignoring path %s outside of %s in change %s\n" % (f, prefix, change))
            continue
        relpath = f[len(prefix):]

        [mode, fileSize] = p4Stat(f)

        gitStream.write("M %s inline %s\n" % (mode, stripRevision(relpath)))
        gitStream.write("data %s\n" % fileSize)
        gitStream.write(os.popen("p4 print -q \"%s\"" % f).read())
        gitStream.write("\n")

    for f in removedFiles:
        if not f.startswith(prefix):
            sys.stderr.write("\ndeleted files: ignoring path %s outside of %s in change %s\n" % (f, prefix, change))
            continue
        relpath = f[len(prefix):]
        gitStream.write("D %s\n" % stripRevision(relpath))

    gitStream.write("\n")

gitStream.close()
gitOutput.close()
gitError.close()

print ""