# SPDX-License-Identifier: GPL-2.0+
#
# Copyright 2020 Google LLC
#
"""Handles the main control logic of patman

This module provides various functions called by the main program to implement
the features of patman.
"""

import os
import sys

from patman import checkpatch
from patman import gitutil
from patman import patchstream
from patman import terminal

def setup():
    """Do required setup before doing anything"""
    gitutil.Setup()

def prepare_patches(col, branch, count, start, end, ignore_binary):
    """Figure out what patches to generate, then generate them

    The patch files are written to the current directory, e.g. 0001_xxx.patch
    0002_yyy.patch

    Args:
        col (terminal.Color): Colour output object
        branch (str): Branch to create patches from (None = current)
        count (int): Number of patches to produce, or -1 to produce patches for
            the current branch back to the upstream commit
        start (int): Start partch to use (0=first / top of branch)
        end (int): End patch to use (0=last one in series, 1=one before that,
            etc.)
        ignore_binary (bool): Don't generate patches for binary files

    Returns:
        Tuple:
            Series object for this series (set of patches)
            Filename of the cover letter as a string (None if none)
            patch_files: List of patch filenames, each a string, e.g.
                ['0001_xxx.patch', '0002_yyy.patch']
    """
    if count == -1:
        # Work out how many patches to send if we can
        count = (gitutil.CountCommitsToBranch(branch) - start)

    if not count:
        sys.exit(col.Color(col.RED,
                           'No commits found to process - please use -c flag'))

    # Read the metadata from the commits
    to_do = count - end
    series = patchstream.GetMetaData(branch, start, to_do)
    cover_fname, patch_files = gitutil.CreatePatches(
        branch, start, to_do, ignore_binary, series)

    # Fix up the patch files to our liking, and insert the cover letter
    patchstream.FixPatches(series, patch_files)
    if cover_fname and series.get('cover'):
        patchstream.InsertCoverLetter(cover_fname, series, to_do)
    return series, cover_fname, patch_files

def check_patches(series, patch_files, run_checkpatch, verbose):
    """Run some checks on a set of patches

    This santiy-checks the patman tags like Series-version and runs the patches
    through checkpatch

    Args:
        series (Series): Series object for this series (set of patches)
        patch_files (list): List of patch filenames, each a string, e.g.
            ['0001_xxx.patch', '0002_yyy.patch']
        run_checkpatch (bool): True to run checkpatch.pl
        verbose (bool): True to print out every line of the checkpatch output as
            it is parsed

    Returns:
        bool: True if the patches had no errors, False if they did
    """
    # Do a few checks on the series
    series.DoChecks()

    # Check the patches, and run them through 'git am' just to be sure
    if run_checkpatch:
        ok = checkpatch.CheckPatches(verbose, patch_files)
    else:
        ok = True
    return ok


def email_patches(col, series, cover_fname, patch_files, process_tags, its_a_go,
                  ignore_bad_tags, add_maintainers, limit, dry_run, in_reply_to,
                  thread, smtp_server):
    """Email patches to the recipients

    This emails out the patches and cover letter using 'git send-email'. Each
    patch is copied to recipients identified by the patch tag and output from
    the get_maintainer.pl script. The cover letter is copied to all recipients
    of any patch.

    To make this work a CC file is created holding the recipients for each patch
    and the cover letter. See the main program 'cc_cmd' for this logic.

    Args:
        col (terminal.Color): Colour output object
        series (Series): Series object for this series (set of patches)
        cover_fname (str): Filename of the cover letter as a string (None if
            none)
        patch_files (list): List of patch filenames, each a string, e.g.
            ['0001_xxx.patch', '0002_yyy.patch']
        process_tags (bool): True to process subject tags in each patch, e.g.
            for 'dm: spi: Add SPI support' this would be 'dm' and 'spi'. The
            tags are looked up in the configured sendemail.aliasesfile and also
            in ~/.patman (see README)
        its_a_go (bool): True if we are going to actually send the patches,
            False if the patches have errors and will not be sent unless
            @ignore_errors
        ignore_bad_tags (bool): True to just print a warning for unknown tags,
            False to halt with an error
        add_maintainers (bool): Run the get_maintainer.pl script for each patch
        limit (int): Limit on the number of people that can be cc'd on a single
            patch or the cover letter (None if no limit)
        dry_run (bool): Don't actually email the patches, just print out what
            would be sent
        in_reply_to (str): If not None we'll pass this to git as --in-reply-to.
            Should be a message ID that this is in reply to.
        thread (bool): True to add --thread to git send-email (make all patches
            reply to cover-letter or first patch in series)
        smtp_server (str): SMTP server to use to send patches (None for default)
    """
    cc_file = series.MakeCcFile(process_tags, cover_fname, not ignore_bad_tags,
                                add_maintainers, limit)

    # Email the patches out (giving the user time to check / cancel)
    cmd = ''
    if its_a_go:
        cmd = gitutil.EmailPatches(
            series, cover_fname, patch_files, dry_run, not ignore_bad_tags,
            cc_file, in_reply_to=in_reply_to, thread=thread,
            smtp_server=smtp_server)
    else:
        print(col.Color(col.RED, "Not sending emails due to errors/warnings"))

    # For a dry run, just show our actions as a sanity check
    if dry_run:
        series.ShowActions(patch_files, cmd, process_tags)
        if not its_a_go:
            print(col.Color(col.RED, "Email would not be sent"))

    os.remove(cc_file)

def send(args):
    """Create, check and send patches by email

    Args:
        args (argparse.Namespace): Arguments to patman
    """
    setup()
    col = terminal.Color()
    series, cover_fname, patch_files = prepare_patches(
        col, args.branch, args.count, args.start, args.end,
        args.ignore_binary)
    ok = check_patches(series, patch_files, args.check_patch,
                       args.verbose)

    its_a_go = ok or args.ignore_errors
    if its_a_go:
        email_patches(
            col, series, cover_fname, patch_files, args.process_tags,
            its_a_go, args.ignore_bad_tags, args.add_maintainers,
            args.limit, args.dry_run, args.in_reply_to, args.thread,
            args.smtp_server)