from datetime import datetime
from email.message import Message
import hashlib
import os
import shutil
import subprocess
import tempfile

from test import MailTest


def find(cnt):
    data, login = cnt
    def found(data):
        mime = data.get_content_type()
        if mime == "application/octet-stream":
            mime = _guess_mime(data.get_payload(decode=True))
        if mime == "application/x-xz":
            fname = data.get_filename(login + ".tar.xz")
        elif mime == "application/x-bzip" or mime == "application/x-bzip2":
            fname = data.get_filename(login + ".tar.bz2")
        elif mime == "application/x-gzip" or mime == "application/gzip":
            fname = data.get_filename(login + ".tar.gz")
        elif mime == "application/zip":
            fname = data.get_filename(login + ".zip")
        elif mime == "application/rar":
            fname = data.get_filename(login + ".rar")
        elif mime == "application/x-tar" or mime == "application/tar":
            fname = data.get_filename(login + ".tar")
        else:
            fname = None
        return data.get_payload(decode=True), fname

    if isinstance(data, Message):
        if not data.is_multipart():
            data, fname = found(data)
            yield MailTest("Tarball found: %s." % fname, -1)
        else:
            for part in data.walk():
                data, fname = found(part)
                if fname is not None:
                    yield MailTest("Tarball found: %s." % fname, -1)
                    break
    yield (data, login)


def hash_archive(cnt, dest=None, imposed_hash=None):
    data, login = cnt
    sha = hashlib.sha1(data.encode() if isinstance(data, str) else data).hexdigest()
    yield MailTest("Your tarball SHA-1 is %s." % sha, -1)
    if dest is not None and os.path.exists(os.path.join(dest, login + "." + sha)):
        yield MailTest("You already have uploaded this tarball.", 1)
        yield False
    elif imposed_hash is not None and imposed_hash != sha:
        yield MailTest("This is not the expected hash. Your tarball's hash must be: %s." % imposed_hash, 1)
    else:
        yield (data, sha, login)


def _guess_mime(data):
    with subprocess.Popen(["file",
                           "--brief",
                           "--mime-type",
                           "-"], env={"LANG": 'C'}, stdin=subprocess.PIPE, stdout=subprocess.PIPE) as p:
        p.stdin.write(data.encode() if isinstance(data, str) else data)
        p.stdin.close()
        p.wait()
        if p.returncode == 0:
            return p.stdout.read().decode('utf-8', 'replace').strip()


def guess_mime(cnt):
    data, sha, login = cnt

    mime = _guess_mime(data)
    if mime is not None:
        yield MailTest("Guessed content-type of your submission: %s." % mime,
                       0 if mime.find("application/x-") == 0 else 2)
    else:
        mime = "application/x-tar"
        yield MailTest("Unable to guess content-type of your submission. Assuming: %s." % mime)

    yield data, mime, sha, login


def extract(cnt, dest=None):
    data, type, sha, login = cnt

    if dest is not None:
        odest = dest
        os.makedirs(odest, exist_ok=True)
        ldest = os.path.join(dest, login)
        dest = os.path.join(dest, login + "." + sha)
        if os.path.exists(dest):
            yield MailTest("You already have uploaded this tarball.", 1)
            return
        last_dest = os.readlink(ldest) if os.path.exists(ldest) else None

    try:
        with tempfile.TemporaryDirectory() as temp:
            with subprocess.Popen(["tar", "--no-same-owner", "--no-same-permissions",
                                   ("-xvC" + temp) if dest is not None else "-t",
                                   "-z" if type == "application/x-gzip" else "",
                                   "-J" if type == "application/x-xz" else "",
                                   "-j" if type in ["application/x-bzip", "application/x-bzip2"] else "",
                                   "-"], env={"LANG": 'C'}, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE) as p:
                p.stdin.write(data.encode() if isinstance(data, str) else data)
                p.stdin.close()
                p.wait()
                err = p.stdout.read().decode('utf-8', 'replace')
                err += p.stderr.read().decode('utf-8', 'replace')
                if p.returncode == 0:
                    if dest is not None:
                        nsub = len([x for x in os.listdir(odest) if x.find(os.path.basename(ldest) + ".") == 0]) + 1
                        if nsub > 1:
                            yield MailTest("This is your %i%s submission. Last submission on: %s" % (nsub, "st" if nsub == 0 else ("nd" if nsub == 1 else ("rd" if nsub == 3 else "th")), datetime.fromtimestamp(int(os.lstat(ldest).st_mtime))), -1)
                        else:
                            yield MailTest("This is your %i%s submission." % (nsub, "st" if nsub == 1 else ("nd" if nsub == 2 else ("rd" if nsub == 3 else "th"))), -1)
                        if dest != ldest:
                            if os.path.lexists(ldest):
                                os.remove(ldest)
                            os.symlink(os.path.basename(dest), ldest)
                        if len(os.listdir(temp)) == 1:
                            shutil.move(os.path.join(temp, os.listdir(temp)[0]), dest)
                        else:
                            shutil.move(temp, dest)
                        # Update modification time to reflect submission timestamp
                        os.utime(dest)
                    yield MailTest("Archive successfully extracted.", details=err)
                    yield dest
                else:
                    yield MailTest("An error occured during archive extraction:", 1, details=err)

                if not os.path.exists(temp):
                    os.makedirs(temp)
    except PermissionError:
        if os.path.lexists(ldest):
            os.remove(ldest)
        if last_dest is not None:
            os.symlink(last_dest, ldest)
        yield MailTest("Your archive's content has crazy permissions. Please fix it.", 1)