import json
import os
import logging
import subprocess
import sys
import time
import re
import shutil
from rich.logging import RichHandler
from rich.traceback import install
import configparser
import inflect
from inotify_simple import INotify, flags
import lxml.etree
import lxml.builder
import requests
from requests.auth import HTTPBasicAuth


# TODO Process files that already exist on start

# Exit codes
# 1: Config file invalid, it has no sections
# 2: Config file invalid, sections must define at least CONST.CFG_MANDATORY
# 3: Watch directory does not exist and unable to create
# 4: Unable to create output directory


class CONST(object):
    __slots__ = ()
    LOG_FORMAT = "%(message)s"
    CFG_THIS_FILE_DIRNAME = os.path.dirname(__file__)
    CFG_DEFAULT_FILENAME = "config.ini"
    CFG_DEFAULT_ABS_PATH = os.path.join(CFG_THIS_FILE_DIRNAME, CFG_DEFAULT_FILENAME)
    CFG_KNOWN_DEFAULTS = [
        {"key": "self_name", "value": "kodi-nfo-feeder"},
        {"key": "ignored_target_file_exts", "value": ".jpg, .jpeg, .png, .nfo"},
        {"key": "title_regex_search", "value": ""},
        {"key": "title_regex_replace", "value": ""},
        {"key": "do_seasons", "value": "yes"}
    ]
    CFG_KNOWN_SECTION = [
        {"key": "watch_dir", "is_mandatory": True},
        {"key": "output_dir", "is_mandatory": True},
        {"key": "title_regex_search", "is_mandatory": False},
        {"key": "title_regex_replace", "is_mandatory": False},
        {"key": "do_seasons", "is_mandatory": False},
        {"key": "run_cmd", "is_mandatory": False},
        {"key": "kodi_jsonrpc_address", "is_mandatory": False},
        {"key": "kodi_jsonrpc_username", "is_mandatory": False},
        {"key": "kodi_jsonrpc_password", "is_mandatory": False}
    ]
    CFG_MANDATORY = [section_cfg["key"] for section_cfg in CFG_KNOWN_SECTION if section_cfg["is_mandatory"]]


CONST = CONST()
logging.basicConfig(
    # Default for all modules in NOTSET so log everything
    level="NOTSET",
    format=CONST.LOG_FORMAT,
    datefmt="[%X]",
    handlers=[RichHandler(
        show_time=False if "SYSTEMD_EXEC_PID" in os.environ else True,
        rich_tracebacks=True
    )]
)
log = logging.getLogger("rich")
# Our own code logs with this level
log.setLevel(logging.DEBUG)
logging.getLogger("urllib3.connectionpool").setLevel(logging.WARNING)
install(show_locals=True)


class ConfigParser(
        configparser.ConfigParser):
    """Can get options() without defaults

    Taken from https://stackoverflow.com/a/12600066.
    """

    def options(self, section, no_defaults=False, **kwargs):
        if no_defaults:
            try:
                return list(self._sections[section].keys())
            except KeyError:
                raise configparser.NoSectionError(section)
        else:
            return super().options(section)


p = inflect.engine()

ini_defaults = []
internal_defaults = {default["key"]: default["value"] for default in CONST.CFG_KNOWN_DEFAULTS}
config = ConfigParser(defaults=internal_defaults)
config.read(CONST.CFG_DEFAULT_ABS_PATH)
ignored_target_file_exts_str = config.get(config.default_section, "ignored_target_file_exts")
ignored_target_file_exts = re.split(r""",\s?|\s""", ignored_target_file_exts_str)


def print_section_header(
        header: str) -> str:
    return f"Loading config section '[{header}]' ..."


def validate_default_section(
        config_obj: configparser.ConfigParser()) -> None:
    log.debug(f"Loading config from file '{CONST.CFG_DEFAULT_ABS_PATH}' ...")
    if not config_obj.sections():
        log.error(f"No config sections found in '{CONST.CFG_DEFAULT_ABS_PATH}'. Exiting 1 ...")
        sys.exit(1)
    if config.defaults():
        log.debug(f"Symbol legend:\n"
                  f"* Global default from section '[{config_obj.default_section}]'\n"
                  f"~ Local option, doesn't exist in '[{config_obj.default_section}]'\n"
                  f"+ Local override of a value from '[{config_obj.default_section}]'\n"
                  f"= Local override, same value as in '[{config_obj.default_section}]'")
        log.debug(print_section_header(config_obj.default_section))
        for default in config_obj.defaults():
            ini_defaults.append({default: config_obj[config_obj.default_section][default]})
            log.debug(f"* {default} = {config_obj[config_obj.default_section][default]}")
    else:
        log.debug(f"No defaults defined")


def config_has_valid_section(
        config_obj: configparser.ConfigParser()) -> bool:
    has_valid_section = False
    for config_obj_section in config_obj.sections():
        if set(CONST.CFG_MANDATORY).issubset(config_obj.options(config_obj_section)):
            has_valid_section = True
            break
    return has_valid_section


def is_default(
        config_key: str) -> bool:
    return any(config_key in ini_default for ini_default in ini_defaults)


def is_same_as_default(
        config_kv_pair: dict) -> bool:
    return config_kv_pair in ini_defaults


def validate_config_sections(
        config_obj: configparser.ConfigParser()) -> None:
    for this_section in config_obj.sections():
        log.debug(print_section_header(this_section))
        if not set(CONST.CFG_MANDATORY).issubset(config_obj.options(this_section, no_defaults=True)):
            log.warning(f"Config section '[{this_section}]' does not have all mandatory options "
                        f"{CONST.CFG_MANDATORY} set, skipping section ...")
            config_obj.remove_section(this_section)
        else:
            for key in config_obj.options(this_section, no_defaults=True):
                kv_prefix = "~"
                if is_default(key):
                    kv_prefix = "+"
                    if is_same_as_default({key: config_obj[this_section][key]}):
                        kv_prefix = "="
                log.debug(f"{kv_prefix} {key} = {config_obj[this_section][key]}")


def setup_watch(
        csection_name: str,
        config_obj: configparser.ConfigParser(),
        inotify_obj: INotify) -> bool:

    global wds

    watch_this = config_obj.get(csection, "watch_dir")

    if not os.path.exists(watch_this):
        os.makedirs(watch_this, exist_ok=False)
    watch_flags = flags.MOVED_TO
    try:
        log.debug(f"Watching for '[{csection_name}]' files moved to '{watch_this}' ...")
        wd_obj = inotify_obj.add_watch(watch_this, watch_flags)
    except FileNotFoundError:
        log.error(f"Section '[{csection_name}]' watch directory '{watch_this}' does not exist. Please create it. "
                  f"Exiting 3 ...")
        sys.exit(3)
    else:
        log.debug(f"Created watch descriptor ID {wd_obj} for '[{csection_name}]' watch directory '{watch_this}'.")
        wds[wd_obj] = {
            "watch_dir": watch_this,
            "output_dir": config.get(csection, "output_dir"),
            "section": csection_name
        }
        return True


def generate_nfo(
        title: str,
        raw_file_name: str) -> lxml.builder.ElementMaker:

    season_ep_str = raw_file_name.split(" - ")[0]

    data = lxml.builder.ElementMaker()
    ep_details_tag = data.episodedetails
    title_tag = data.title
    id_tag = data.id
    nfo_data = ep_details_tag(
        title_tag(title),
        id_tag(f"{season_ep_str} - {title}")
    )
    return nfo_data


def get_basic_cleaned_title(
        csection_name: str,
        config_obj: configparser.ConfigParser(),
        dirty_title: str) -> str:

    regex_search_pattern = config_obj.get(csection_name, "title_regex_search")
    regex_replace_pattern = config_obj.get(csection_name, "title_regex_replace")
    if regex_search_pattern:
        log.debug(f"Doing basic title cleaning ...")
        pattern = re.compile(regex_search_pattern)
        clean_title = re.sub(pattern, regex_replace_pattern, dirty_title)
        log.debug(f"""Title's now "{clean_title}".""")
        return clean_title
    else:
        return dirty_title


def get_season_and_episode(
        csection_name: str,
        config_obj: configparser.ConfigParser(),
        raw_file_name: str) -> dict:

    file_name_ext_split = os.path.splitext(raw_file_name)
    season_ep_str = file_name_ext_split[0].split(" - ", 1)
    ext = file_name_ext_split[1]
    season_episode = re.split("[S|E]", season_ep_str[0])
    season = f"Season {season_episode[1]}"
    try:
        title = season_ep_str[1]
    except IndexError:
        log.warning(f"File name '{raw_file_name}' is not following expected format. The excepted format "
                    f"is a season-and-episode string followed by space-slash-space and and arbitrary sequence "
                    f"of characters suffixed with a file extension e.g. "
                    f"'S2022E2022032001 - This is a Title.mp4'. Skipping further file processing ...")
        return {}
    else:
        basic_cleaned_title = get_basic_cleaned_title(csection_name, config_obj, title)

        got_season_and_episode = {
            "season_str": season,
            "title_str": basic_cleaned_title,
            "season_ep_list": season_ep_str,
            "ext": ext
        }
        log.debug(f"""Identified {got_season_and_episode["season_str"]}, """
                  f"""title "{got_season_and_episode["title_str"]}" """ 
                  f"and episode object {season_ep_str} "
                  f"with extension '{ext}'.")
        return got_season_and_episode


def get_target_file_list(
        target_dir: str) -> list:

    log.debug(f"Generating list of files in '{target_dir}' ...")
    onlyfiles = [f for f in os.listdir(target_dir) if os.path.isfile(os.path.join(target_dir, f))]
    filtered_files = [f for f in onlyfiles if not f.endswith(tuple(ignored_target_file_exts))]
    log.debug(f"Files in '{target_dir}' filtered for extensions we're ignoring "
              f"{ignored_target_file_exts}: {filtered_files}")
    return filtered_files


def move_file_to_target_dir(
        csection_name: str,
        config_obj: configparser.ConfigParser(),
        raw_file_name: str,
        season_ep_str: dict,
        output_dir_name: str) -> str:

    this_watch_dir = config_obj.get(csection_name, "watch_dir")
    source_abs_path = os.path.join(this_watch_dir, raw_file_name)

    target_dir = output_dir_name
    target_file_list = get_target_file_list(target_dir)

    target_file_name = season_ep_str["season_ep_list"][0]
    target_ext = season_ep_str["ext"]
    target_file_name_plus_ext = f"{target_file_name}{target_ext}"

    if target_file_name_plus_ext in target_file_list:
        log.debug(f"Intended file name already exists in target dir, incrementing counter ...")
        episode_minus_counter = target_file_name[:-2]
        counter = target_file_name[-2:]
        counter_length = len(counter)
        counter_stripped = int(counter.lstrip("0"))
        counter_stripped += 1
        target_file_name = f"{episode_minus_counter}{str(counter_stripped).zfill(counter_length)}"
    target_abs_path = os.path.join(target_dir, f"{target_file_name}{target_ext}")

    try:
        log.debug(f"Moving '{source_abs_path}' to '{target_abs_path}' ...")
        shutil.move(source_abs_path, target_abs_path)
    except OSError as move_ose:
        log.error(f"Failed moving file with an OSError:\n"
                  f"{move_ose}\n"
                  f"Continuing file watch ...")
        return ""
    else:
        return target_file_name


def write_nfo_to_disk(
        nfo_data: lxml.builder.ElementMaker,
        target_file_name: str,
        output_dir_name: str) -> bool:

    target_dir = output_dir_name
    target_nfo_name = f"{target_file_name}.nfo"
    target_abs_path = os.path.join(target_dir, target_nfo_name)

    nfo_str = lxml.etree.tostring(
        nfo_data,
        pretty_print=True,
        xml_declaration=True,
        standalone=True,
        encoding="UTF-8")
    try:
        with open(target_abs_path, 'wb') as nfo_file:
            log.debug(f"Writing NFO data to '{target_abs_path}':\n"
                      f"""{nfo_str.decode("UTF-8")}""")
            nfo_file.write(nfo_str)
    except OSError as nfo_ose:
        log.error(f"Failed writing NFO file '{target_abs_path}' with an OSError:\n"
                  f"{nfo_ose}\n"
                  f"Continuing file watch ...")
        return False
    else:
        return True


def kodi_library_update(
        csection_name: str,
        config_obj: configparser.ConfigParser()) -> bool:

    kodi_jsonrpc_address = config_obj.get(csection_name, "kodi_jsonrpc_address")
    kodi_jsonrpc_username = config_obj.get(csection_name, "kodi_jsonrpc_username") if \
        config.has_option(csection_name, "kodi_jsonrpc_username") else None
    kodi_jsonrpc_password = config_obj.get(csection_name, "kodi_jsonrpc_password") if \
        config.has_option(csection_name, "kodi_jsonrpc_password") else None

    require_auth = False
    if (kodi_jsonrpc_username and not kodi_jsonrpc_password) or \
            (not kodi_jsonrpc_username and kodi_jsonrpc_password):
        log.warning(f"Please make sure that both a Kodi username /and/ and password are set via "
                    f"the 'kodi_jsonrpc_username' and 'kodi_jsonrpc_password' config options, respectively. "
                    f"If Kodi's web interface is configured to not require authentication please set "
                    f"both 'kodi_jsonrpc_username' and 'kodi_jsonrpc_password' to empty values (or simply remove "
                    f"both lines from the config file).\n"
                    f"Skipping Kodi video library reload ...")
        return False
    elif kodi_jsonrpc_username and kodi_jsonrpc_password:
        require_auth = True

    json_payload_str = {
        "jsonrpc": "2.0",
        "method": "VideoLibrary.Scan",
        "id": f"""{config_obj.get(csection_name, "self_name")}_trigger-vid-lib-scan"""
    }
    json_payload = json.dumps(json_payload_str)
    req_header = {"content-type": "application/json"}
    s = requests.Session()
    req = requests.Request(
        "POST",
        kodi_jsonrpc_address,
        data=json_payload,
        auth=requests.auth.HTTPBasicAuth(
            kodi_jsonrpc_username,
            kodi_jsonrpc_password
        ) if require_auth else None,
        headers=req_header)
    prepped = req.prepare()
    newline = "\n"
    log.debug(f"Triggering Kodi library update ...")
    log.debug(f"Request method: {req.method}\n"
              f"URL: {req.url}\n"
              f"""{newline.join(f"Header '{header}': '{value}'" for header, value in list(req.headers.items()))}\n"""
              f"Payload: {json_payload}")
    try:
        with s.send(prepped) as s:
            got_json_response = s.content
            if s.status_code == requests.codes.ok:
                log.debug(f"Kodi library update successful")
                return True
            else:
                log.error(f"Request failed, response code was {s.status_code}:\n"
                          f"{json.loads(got_json_response)}")
                return False
    except requests.exceptions.ConnectionError:
        log.info(f"Kodi JSON-RPC endpoint {kodi_jsonrpc_address} is not currently connectable.")
        return False


if __name__ == '__main__':
    validate_default_section(config)
    if config_has_valid_section(config):
        validate_config_sections(config)
    else:
        log.error(f"No valid config section found. A valid config section has at least the mandatory "
                  f"""{p.plural("option", len(CONST.CFG_MANDATORY))} """
                  f"{CONST.CFG_MANDATORY} set. Exiting 2 ...")
        sys.exit(2)

    inotify = INotify()
    wds = {}
    log.debug(f"Iterating over config sections ...")

    for csection in config.sections():
        log.debug(f"Processing section '[{csection}]' ...")
        setup_watch(csection, config, inotify)

    while True:
        time.sleep(0.2)
        for event in inotify.read():
            events = [str(flags) for flags in flags.from_mask(event.mask)]
            if "flags.MOVED_TO" in events:
                file_name = event.name
                watch_dir_config = wds[event.wd]
                watch_dir = watch_dir_config["watch_dir"]
                output_dir = watch_dir_config["output_dir"]
                section_name = watch_dir_config["section"]
                log.debug(f"Watch dir config: {watch_dir_config}")
                log.info(f"File '{file_name}' was moved to watch directory "
                         f"""'{watch_dir}', processing ...""")

                season_and_episode = get_season_and_episode(section_name, config, file_name)
                if not season_and_episode:
                    break

                if config.getboolean(section_name, "do_seasons"):
                    season_str = season_and_episode["season_str"]
                    log.debug(f"Changing output to season-specific dir '{season_str}' ...")
                    output_dir = os.path.join(output_dir, season_str)

                try:
                    os.makedirs(output_dir, exist_ok=True)
                except OSError as ose:
                    log.error(f"Unable to create section '[{section_name}]' output dir "
                              f"'{output_dir}' with an OSError:\n"
                              f"{ose}\n"
                              f"Exiting 4 ...")
                    sys.exit(4)

                nfo = generate_nfo(season_and_episode["title_str"], file_name)
                file_moved_to_target_dir = move_file_to_target_dir(
                    section_name,
                    config,
                    file_name,
                    season_and_episode,
                    output_dir)
                if file_moved_to_target_dir:
                    write_nfo_to_disk(
                        nfo,
                        file_moved_to_target_dir,
                        output_dir)

                run_cmd = config.get(section_name, "run_cmd") if config.has_option(section_name, "run_cmd") else False
                if run_cmd:
                    log.debug(f"Executing post-move command: {run_cmd} ...")
                    run_cmd_result = subprocess.getstatusoutput(run_cmd)
                    run_cmd_exit_code = run_cmd_result[0]
                    run_cmd_output = run_cmd_result[1]
                    if run_cmd_exit_code != 0:
                        log.warning(f"Post-move command failed with exit code {run_cmd_exit_code}:\n"
                                    f"{run_cmd_output}")

                if config.has_option(section_name, "kodi_jsonrpc_address"):
                    kodi_library_update(section_name, config)