import subprocess
from email.utils import format_datetime
import quopri
import os
import re

MAX_HAM = 1.0 / 4.0
MIN_SPAM = 3.0 / 4.0
MIN_DEV = 2 * (MIN_SPAM - MAX_HAM) * 0.375
ROBS = 0.0178 
ROBX = (MAX_HAM + MIN_SPAM) / 2
LOAD_COMMAND = ["bogoutil", "-l"]
COMMAND = ["bogofilter", "-T", "-c", "/dev/null", "-o", "{},{}".format(MIN_SPAM, MAX_HAM), "-m", "{},{},{}".format(MIN_DEV, ROBS, ROBX)]

# Categories
SPAM   = "S"
HAM    = "H"
UNSURE = "U"
categories = [SPAM, HAM, UNSURE]

# Actions
CLASSIFY     = 0
REGISTER     = 1
LEARN_SPAM   = 2
UNLEARN_SPAM = 3
LEARN_HAM    = 4
UNLEARN_HAM  = 5

ACTIONS = {
    CLASSIFY:     [],
    REGISTER:     ["-u"],
    LEARN_SPAM:   ["-s"],
    UNLEARN_SPAM: ["-S"],
    LEARN_HAM:    ["-n"],
    UNLEARN_HAM:  ["-N"],

    SPAM:         ["-s"],
    HAM:          ["-n"],
    UNSURE:       []
}

class BogofilterResult:
    def __init__(self, category, score):
        self.category = category
        self.score = score

class Mail:
    def __init__(self, headers = {}, body = []):
        self.headers = {**headers, "Content-Type": "text/html; charset=\"UTF-8\""}
        self.change_body(body)

    def get_body(self):
        return "\n".join(self.body)

    def change_body(self, body):
        if isinstance(body, str):
            self.body = body.strip().split("\n")
        else:
            self.body = list(body)

    def format(self, mbox = False):
        lines = []
       
        if mbox:
            lines.append("From {} {}\n".format(self.headers["From"], format_datetime(datetime.now(timezone.utc), usegmt = True)))

        for key, value in self.headers.items():
            if key == "Subject":
                value = "=?utf-8?Q?{}?=".format(quopri.encodestring(bytes(value, "utf-8"), header = True).decode("utf-8"))
            lines.append("{}: {}".format(key, value))
        lines.append("")

        if mbox:
            lines.extend([">" + line if re.match(r">*From ", line) else line for line in self.body])
        else:
            lines.extend(self.body)

        return "\n".join(lines)

    def deliver_to_mbox(path, mode = "a+"):
        empty = not os.path.exists(path) or os.path.getsize(path) == 0
        with open(path, mode, encoding = "utf-8") as mbox_file:
            if not empty:
                mbox_file.write("\n")
            mbox_file.write(self.format(mbox = True))

def run(text, db_dir, actions = [CLASSIFY], category = UNSURE):
    args = []
    for action in actions:
        args.extend(ACTIONS[action])
    
    if not os.path.exists(os.path.join(db_dir, "wordlist.db")):
        os.makedirs(db_dir, exist_ok = True)
        subprocess.run(LOAD_COMMAND + [db_dir], input = b'')

    cp = subprocess.run(COMMAND + ["-d", db_dir] + args, capture_output = True, encoding = "utf-8", input = text)
    arr = cp.stdout.strip().split(" ")
    if len(arr) == 2:
        (category, score) = arr
        return BogofilterResult(category, float(score))
    else:
        if cp.returncode == 3:
            print("Bogofilter error:")
            if cp.stdout.strip():
                print(cp.stderr.strip())
        return None

#mail = Mail({"From": "thor"}, "Hello, World\nHow are you?")
#print(mail.format())