#!/usr/bin/python3
import os
import time
import urllib.request
import sqlite3
import feedparser
import argparse
import logging
import email
import email.utils
import smtplib
import subprocess
import sys
from datetime import date
from enum import Enum

URL = "https://lore.kernel.org/linux-firmware/new.atom"


class ContentType(Enum):
    REPLY = 1
    PATCH = 2
    PULL_REQUEST = 3
    SPAM = 4


content_types = {
    "are available in the Git repository at": ContentType.PULL_REQUEST,
    "diff --git": ContentType.PATCH,
    "Signed-off-by:": ContentType.PATCH,
}


def classify_content(content):
    # load content into the email library
    msg = email.message_from_string(content)
    decoded = None
    body = None

    # check the subject
    subject = msg["Subject"]
    if "Re:" in subject:
        return ContentType.REPLY
    if "PATCH" in subject:
        return ContentType.PATCH

    if msg.is_multipart():
        for part in msg.walk():
            if part.get_content_type() == "text/plain":
                body = part.get_payload(decode=True)
    else:
        body = msg.get_payload(decode=True)

    if body:
        for encoding in ["utf-8", "windows-1252"]:
            try:
                decoded = body.decode(encoding)
                break
            except UnicodeDecodeError:
                pass

    if decoded:
        for key in content_types.keys():
            if key in decoded:
                return content_types[key]
    else:
        logging.warning("Failed to decode email: %s, treating as SPAM", body)

    return ContentType.SPAM


def fetch_url(url):
    with urllib.request.urlopen(url) as response:
        return response.read().decode("utf-8")


def quiet_cmd(cmd):
    logging.debug("Running {}".format(cmd))
    output = subprocess.check_output(cmd, stderr=subprocess.STDOUT)
    logging.debug(output)


def reply_email(content, branch):
    user = None
    password = None
    server = None
    port = None

    if "SMTP_USER" in os.environ:
        user = os.environ["SMTP_USER"]
    if "SMTP_PASS" in os.environ:
        password = os.environ["SMTP_PASS"]
    if "SMTP_SERVER" in os.environ:
        server = os.environ["SMTP_SERVER"]
    if "SMTP_PORT" in os.environ:
        port = os.environ["SMTP_PORT"]
    if not user or not password or not server or not port:
        logging.debug("Missing SMTP configuration, not sending email")
        return

    reply = email.message.EmailMessage()

    orig = email.message_from_string(content)
    try:
        reply["To"] = ", ".join(
            email.utils.formataddr(t)
            for t in email.utils.getaddresses(
                orig.get_all("from", [])
                + orig.get_all("to", [])
                + orig.get_all("cc", [])
            )
        )
    except ValueError:
        logging.warning("Failed to parse email addresses, not sending email")
        return

    reply["From"] = "linux-firmware@kernel.org"
    try:
        reply["Subject"] = "Re: {}".format(orig["Subject"])
    except ValueError:
        logging.warning("Failed to parse subject, not sending email")
        return

    reply["In-Reply-To"] = orig["Message-Id"]
    reply["References"] = orig["Message-Id"]
    reply["Thread-Topic"] = orig["Thread-Topic"]
    reply["Thread-Index"] = orig["Thread-Index"]

    content = (
        "Your request has been forwarded by the Linux Firmware Kernel robot.\n"
        "Please follow up at https://gitlab.com/kernel-firmware/linux-firmware/-/merge_requests to ensure it gets merged\n"
        "Your request is '{}'".format(branch)
    )
    reply.set_content(content)

    mailserver = smtplib.SMTP(server, port)
    mailserver.ehlo()
    mailserver.starttls()
    mailserver.ehlo()
    mailserver.login(user, password)
    mailserver.sendmail(reply["From"], reply["To"], reply.as_string())
    mailserver.quit()


def create_pr(remote, branch):
    cmd = [
        "git",
        "push",
        "-u",
        remote,
        branch,
        "-o",
        "merge_request.create",
        "-o",
        "merge_request.remove_source_branch",
        "-o",
        "merge_request.target=main",
        "-o",
        "merge_request.title={}".format(branch),
    ]
    quiet_cmd(cmd)


def refresh_branch():
    quiet_cmd(["git", "checkout", "main"])
    quiet_cmd(["git", "pull"])


def delete_branch(branch):
    quiet_cmd(["git", "checkout", "main"])
    quiet_cmd(["git", "branch", "-D", branch])


def process_pr(mbox, num, remote):
    branch = "robot/pr-{}-{}".format(num, int(time.time()))

    # manual fixup for PRs from drm firmware repo
    if "git@gitlab.freedesktop.org:drm/firmware.git" in mbox:
        mbox = mbox.replace(
            "git@gitlab.freedesktop.org:drm/firmware.git",
            "https://gitlab.freedesktop.org/drm/firmware.git",
        )

    cmd = ["b4", "--debug", "pr", "-b", branch, "-"]
    logging.debug("Running {}".format(cmd))
    p = subprocess.Popen(
        cmd, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE
    )
    stdout, stderr = p.communicate(mbox.encode("utf-8"))
    for line in stdout.splitlines():
        logging.debug(line.decode("utf-8"))
    for line in stderr.splitlines():
        logging.debug(line.decode("utf-8"))

    # determine if it worked (we can't tell unfortunately by return code)
    cmd = ["git", "branch", "--list", branch]
    logging.debug("Running {}".format(cmd))
    result = subprocess.check_output(cmd)

    if result:
        for line in result.splitlines():
            logging.debug(line.decode("utf-8"))
        logging.info("Forwarding PR for {}".format(branch))
        if remote:
            create_pr(remote, branch)
        delete_branch(branch)
        return branch
    return None


def process_patch(mbox, num, remote):
    # create a new branch for the patch
    branch = "robot/patch-{}-{}".format(num, int(time.time()))
    cmd = ["git", "checkout", "-b", branch]
    quiet_cmd(cmd)

    # apply the patch
    cmd = ["git", "am"]
    logging.debug("Running {}".format(cmd))
    p = subprocess.Popen(
        cmd, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE
    )
    stdout, stderr = p.communicate(mbox.encode("utf-8"))
    for line in stdout.splitlines():
        logging.debug(line.decode("utf-8"))
    for line in stderr.splitlines():
        logging.debug(line.decode("utf-8"))
    if p.returncode != 0:
        quiet_cmd(["git", "am", "--abort"])
    else:
        logging.info("Opening PR for {}".format(branch))
        if remote:
            create_pr(remote, branch)

    delete_branch(branch)
    if p.returncode == 0:
        return branch
    return None


def update_database(conn, url):
    c = conn.cursor()

    c.execute(
        """CREATE TABLE IF NOT EXISTS firmware (url text, processed integer default 0, spam integer default 0)"""
    )

    # local file
    if os.path.exists(url):
        with open(url, "r") as f:
            atom = f.read()
    # remote file
    else:
        logging.info("Fetching {}".format(url))
        atom = fetch_url(url)

    # Parse the atom and extract the URLs
    feed = feedparser.parse(atom)

    # Insert the URLs into the database (oldest first)
    feed["entries"].reverse()
    for entry in feed["entries"]:
        c.execute("SELECT url FROM firmware WHERE url = ?", (entry.link,))
        if c.fetchone():
            continue
        c.execute("INSERT INTO firmware VALUES (?, ?, ?)", (entry.link, 0, 0))

    # Commit the changes and close the connection
    conn.commit()


def process_database(conn, remote):
    c = conn.cursor()

    # get all unprocessed urls that aren't spam
    c.execute("SELECT url FROM firmware WHERE processed = 0 AND spam = 0")
    num = 0
    msg = ""

    rows = c.fetchall()

    if not rows:
        logging.info("No new entries")
        return

    refresh_branch()

    # loop over all unprocessed urls
    for row in rows:
        branch = None
        msg = "Processing ({}%)".format(round(num / len(rows) * 100))
        print(msg, end="\r", flush=True)

        url = "{}raw".format(row[0])
        logging.debug("Processing {}".format(url))
        mbox = fetch_url(url)
        classification = classify_content(mbox)

        if classification == ContentType.PATCH:
            logging.debug("Processing patch ({})".format(row[0]))
            branch = process_patch(mbox, num, remote)

        if classification == ContentType.PULL_REQUEST:
            logging.debug("Processing PR ({})".format(row[0]))
            branch = process_pr(mbox, num, remote)

        if classification == ContentType.SPAM:
            logging.debug("Marking spam ({})".format(row[0]))
            c.execute("UPDATE firmware SET spam = 1 WHERE url = ?", (row[0],))

        if classification == ContentType.REPLY:
            logging.debug("Ignoring reply ({})".format(row[0]))

        c.execute("UPDATE firmware SET processed = 1 WHERE url = ?", (row[0],))
        num += 1
        print(" " * len(msg), end="\r", flush=True)

        # commit changes
        conn.commit()

        # send any emails
        if branch:
            reply_email(mbox, branch)

    logging.info("Finished processing {} new entries".format(len(rows)))


if __name__ == "__main__":
    parser = argparse.ArgumentParser(description="Process linux-firmware mailing list")
    parser.add_argument("--url", default=URL, help="URL to get ATOM feed from")
    parser.add_argument(
        "--database",
        default=os.path.join("contrib", "linux_firmware.db"),
        help="sqlite database to store entries in",
    )
    parser.add_argument("--dry", action="store_true", help="Don't open pull requests")
    parser.add_argument(
        "--debug", action="store_true", help="Enable debug logging to console"
    )
    parser.add_argument("--remote", default="origin", help="Remote to push to")
    parser.add_argument(
        "--refresh-cycle", default=0, help="How frequently to run (in minutes)"
    )
    args = parser.parse_args()

    if not os.path.exists("WHENCE"):
        logging.critical(
            "Please run this script from the root of the linux-firmware repository"
        )
        sys.exit(1)

    log = os.path.join(
        "contrib",
        "{prefix}-{date}.{suffix}".format(
            prefix="linux_firmware", suffix="txt", date=date.today()
        ),
    )
    logging.basicConfig(
        format="%(asctime)s %(levelname)s:\t%(message)s",
        filename=log,
        filemode="w",
        level=logging.DEBUG,
    )

    # set a format which is simpler for console use
    console = logging.StreamHandler()
    if args.debug:
        console.setLevel(logging.DEBUG)
    else:
        console.setLevel(logging.INFO)
    formatter = logging.Formatter("%(asctime)s : %(levelname)s : %(message)s")
    console.setFormatter(formatter)
    logging.getLogger("").addHandler(console)

    while True:
        conn = sqlite3.connect(args.database)
        # update the database
        update_database(conn, args.url)

        if args.dry:
            remote = ""
        else:
            remote = args.remote

        # process the database
        process_database(conn, remote)

        conn.close()

        if args.refresh_cycle:
            logging.info("Sleeping for {} minutes".format(args.refresh_cycle))
            time.sleep(int(args.refresh_cycle) * 60)
        else:
            break