# Copyright 2020 Joerg Sonnenberger <joerg@bec.de>

#

# This software may be used and distributed according to the terms of the

# GNU General Public License version 2 or any later version.

"""export repositories as git fast-import stream"""

# The format specification for fast-import streams can be found at

# https://git-scm.com/docs/git-fast-import#_input_format

import re

from mercurial.i18n import _

from mercurial.node import hex, nullrev

from mercurial.utils import stringutil

from mercurial import (

    error,

    logcmdutil,

    registrar,

    scmutil,

)

from .convert import convcmd

# Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for

# extensions which SHIP WITH MERCURIAL. Non-mainline extensions should

# be specifying the version(s) of Mercurial they are tested with, or

# leave the attribute unspecified.

testedwith = b"ships-with-hg-core"

cmdtable = {}

command = registrar.command(cmdtable)

GIT_PERSON_PROHIBITED = re.compile(b'[<>\n"]')

GIT_EMAIL_PROHIBITED = re.compile(b"[<> \n]")

def convert_to_git_user(authormap, user, rev):

    mapped_user = authormap.get(user, user)

    user_person = stringutil.person(mapped_user)

    user_email = stringutil.email(mapped_user)

    if GIT_EMAIL_PROHIBITED.match(user_email) or GIT_PERSON_PROHIBITED.match(

        user_person

    ):

        raise error.Abort(

            _(b"Unable to parse user into person and email for revision %s")

            % rev

        )

    if user_person:

        return b'"%s" <%s>' % (user_person, user_email)

    else:

        return b"<%s>" % user_email

def convert_to_git_date(date):

    timestamp, utcoff = date

    tzsign = b"+" if utcoff <= 0 else b"-"

    if utcoff % 60 != 0:

        raise error.Abort(

            _(b"UTC offset in %b is not an integer number of seconds") % (date,)

        )

    utcoff = abs(utcoff) // 60

    tzh = utcoff // 60

    tzmin = utcoff % 60

    return b"%d " % int(timestamp) + tzsign + b"%02d%02d" % (tzh, tzmin)

def convert_to_git_ref(branch):

    # XXX filter/map depending on git restrictions

    return b"refs/heads/" + branch

def write_data(buf, data, add_newline=False):

    buf.append(b"data %d\n" % len(data))

    buf.append(data)

    if add_newline or data[-1:] != b"\n":

        buf.append(b"\n")

def export_commit(ui, repo, rev, marks, authormap):

    ctx = repo[rev]

    revid = ctx.hex()

    if revid in marks:

        ui.debug(b"warning: revision %s already exported, skipped\n" % revid)

        return

    parents = [p for p in ctx.parents() if p.rev() != nullrev]

    for p in parents:

        if p.hex() not in marks:

            ui.warn(

                _(b"warning: parent %s of %s has not been exported, skipped\n")

                % (p, revid)

            )

            return

    # For all files modified by the commit, check if they have already

    # been exported and otherwise dump the blob with the new mark.

    for fname in ctx.files():

        if fname not in ctx:

            continue

        filectx = ctx.filectx(fname)

        filerev = hex(filectx.filenode())

        if filerev not in marks:

            mark = len(marks) + 1

            marks[filerev] = mark

            data = filectx.data()

            buf = [b"blob\n", b"mark :%d\n" % mark]

            write_data(buf, data, True)

            ui.write(*buf, keepprogressbar=True)

            del buf

    # Assign a mark for the current revision for references by

    # latter merge commits.

    mark = len(marks) + 1

    marks[revid] = mark

    ref = convert_to_git_ref(ctx.branch())

    buf = [

        b"commit %s\n" % ref,

        b"mark :%d\n" % mark,

        b"committer %s %s\n"

        % (

            convert_to_git_user(authormap, ctx.user(), revid),

            convert_to_git_date(ctx.date()),

        ),

    ]

    write_data(buf, ctx.description())

    if parents:

        buf.append(b"from :%d\n" % marks[parents[0].hex()])

    if len(parents) == 2:

        buf.append(b"merge :%d\n" % marks[parents[1].hex()])

        p0ctx = repo[parents[0]]

        files = ctx.manifest().diff(p0ctx.manifest())

    else:

        files = ctx.files()

    filebuf = []

    for fname in files:

        if fname not in ctx:

            filebuf.append((fname, b"D %s\n" % fname))

        else:

            filectx = ctx.filectx(fname)

            filerev = filectx.filenode()

            fileperm = b"755" if filectx.isexec() else b"644"

            changed = b"M %s :%d %s\n" % (fileperm, marks[hex(filerev)], fname)

            filebuf.append((fname, changed))

    filebuf.sort()

    buf.extend(changed for (fname, changed) in filebuf)

    del filebuf

    buf.append(b"\n")

    ui.write(*buf, keepprogressbar=True)

    del buf

isrev = re.compile(b"^[0-9a-f]{40}$")

@command(

    b"fastexport",

    [

        (b"r", b"rev", [], _(b"revisions to export"), _(b"REV")),

        (b"i", b"import-marks", b"", _(b"old marks file to read"), _(b"FILE")),

        (b"e", b"export-marks", b"", _(b"new marks file to write"), _(b"FILE")),

        (

            b"A",

            b"authormap",

            b"",

            _(b"remap usernames using this file"),

            _(b"FILE"),

        ),

    ],

    _(b"[OPTION]... [REV]..."),

    helpcategory=command.CATEGORY_IMPORT_EXPORT,

)

def fastexport(ui, repo, *revs, **opts):

    """export repository as git fast-import stream

    This command lets you dump a repository as a human-readable text stream.

    It can be piped into corresponding import routines like "git fast-import".

    Incremental dumps can be created by using marks files.

    """

    revs += tuple(opts.get("rev", []))

    if not revs:

        revs = scmutil.revrange(repo, [b":"])

    else:

        revs = logcmdutil.revrange(repo, revs)

    if not revs:

        raise error.Abort(_(b"no revisions matched"))

    authorfile = opts.get("authormap")

    if authorfile:

        authormap = convcmd.readauthormap(ui, authorfile)

    else:

        authormap = {}

    import_marks = opts.get("import_marks")

    marks = {}

    if import_marks:

        with open(import_marks, "rb") as import_marks_file:

            for line in import_marks_file:

                line = line.strip()

                if not isrev.match(line) or line in marks:

                    raise error.Abort(_(b"Corrupted marks file"))

                marks[line] = len(marks) + 1

    revs.sort()

    with ui.makeprogress(

        _(b"exporting"), unit=_(b"revisions"), total=len(revs)

    ) as progress:

        for rev in revs:

            export_commit(ui, repo, rev, marks, authormap)

            progress.increment()

    export_marks = opts.get("export_marks")

    if export_marks:

        with open(export_marks, "wb") as export_marks_file:

            output_marks = [None] * len(marks)

            for k, v in marks.items():

                output_marks[v - 1] = k

            for k in output_marks:

                export_marks_file.write(k + b"\n")