import datetime
import logging

import dateparser
import discord
import pytz
from apscheduler.triggers.date import DateTrigger
from discord.errors import NotFound
from discord.ext import commands
from discord_slash import SlashCommand, SlashContext
from discord_slash.error import IncorrectFormat, RequestFailure
from discord_slash.model import SlashCommandOptionType
from discord_slash.utils.manage_commands import create_choice, create_option

from discord_reminder_bot.settings import bot_token, config_timezone, log_level, scheduler, sqlite_location

bot = commands.Bot(
    description="Reminder bot for Discord by TheLovinator#9276",
    intents=discord.Intents.all(),
)
slash = SlashCommand(bot, sync_commands=True)


def calc_countdown(job) -> str:
    """Get trigger time from a reminder and calculate how many days,
    hours and minutes till trigger.

    Days/Minutes will not be included if 0.

    Args:
        job: The job. Can be cron, interval or normal.

    Returns:
        Returns days, hours and minutes till reminder. Returns
        "Failed to calculate time" if no job is found.
    """
    # TODO: This "breaks" when only seconds are left.
    # If we use (in {calc_countdown(job)}) it will show (in )

    if type(job.trigger) is DateTrigger:
        trigger_time = job.trigger.run_date
    else:
        trigger_time = job.next_run_time

    # Get_job() returns None when it can't find a job with that id.
    if trigger_time is None:
        # TODO: Change this to None and send this text where needed.
        return "Failed to calculate time"

    # Get time and date the job will run and calculate how many days,
    # hours and seconds.
    countdown = trigger_time - datetime.datetime.now(tz=pytz.timezone(config_timezone))

    days, hours, minutes = (
        countdown.days,
        countdown.seconds // 3600,
        countdown.seconds // 60 % 60,
    )

    # TODO: Explain this.
    return ", ".join(
        f"{x} {y}{'s'*(x!=1)}"
        for x, y in (
            (days, "day"),
            (hours, "hour"),
            (minutes, "minute"),
        )
        if x
    )


@bot.event
async def on_slash_command_error(ctx: SlashContext, ex: Exception):
    logging.error(f"Error occurred during the execution of '/{ctx.name} {ctx.subcommand_name}' by {ctx.author}: {ex}")
    if ex == RequestFailure:
        message = f"Request to Discord API failed: {ex}"
    elif ex == IncorrectFormat:
        message = f"Incorrect format: {ex}"
    elif ex == NotFound:
        message = f"I couldn't find the interaction or it took me longer than 3 seconds to respond: {ex}"
    else:
        message = f"Error occurred during the execution of '/{ctx.name} {ctx.subcommand_name}': {ex}"

    await ctx.send(
        f"{message}\nIf this persists, please make an issue on the"
        "[GitHub repo](https://github.com/TheLovinator1/discord-reminder-bot/issues) or contact TheLovinator#9276",
        hidden=True,
    )


@bot.event
async def on_ready():
    logging.info(f"Logged in as {bot.user.name}")


@slash.subcommand(
    base="remind",
    name="modify",
    description="Modify a reminder. Does not work with cron or interval.",
    options=[
        create_option(
            name="time_or_message",
            description="Choose between modifying the date or the message.",
            option_type=SlashCommandOptionType.STRING,
            required=True,
            choices=[
                create_choice(name="Date", value="date"),
                create_choice(name="Message", value="message"),
            ],
        ),
    ],
)
async def command_modify(ctx: SlashContext, time_or_message: str):
    """Modify a reminder. You can change time or message.

    Args:
        time_or_message: Choose between modifying the message or time.
    """
    # TODO: Reduce complexity.

    # Only make a list with normal reminders.
    jobs_dict = await send_list(ctx, skip_cron_or_interval=True)

    if time_or_message == "date":
        date_or_message = "the date"
    else:
        date_or_message = "the message"

    await ctx.channel.send(
        f"Type the corresponding number to the reminder were you wish to change {date_or_message}."
        " Does not work with cron or interval. Type Exit to exit."
    )

    # Only check for response from the original user and in the
    # correct channel
    def check(m):
        return m.author == ctx.author and m.channel == ctx.channel

    # TODO: Add timeout
    response_message = await bot.wait_for("message", check=check)
    if response_message.clean_content == "Exit":
        return await ctx.channel.send("Exiting...")

    for num, job_from_dict in jobs_dict.items():
        if int(response_message.clean_content) == num:

            job = scheduler.get_job(job_from_dict)

            # Get_job() returns None when it can't find a job with that id.
            if job is None:
                await ctx.send(f"No reminder with ID ({job_from_dict}).")
                return

            message = job.kwargs.get("message")
            old_time = calc_countdown(job)

            channel_name = bot.get_channel(int(job.kwargs.get("channel_id")))
            msg = f"**Modified** {job_from_dict} in #{channel_name}\n"
            if time_or_message == "message":
                await ctx.channel.send("Type the new message. Type Exit to exit.")

                # TODO: Add timeout
                response_new_message = await bot.wait_for("message", check=check)

                if response_new_message.clean_content == "Exit":
                    return await ctx.channel.send("Exiting...")

                scheduler.modify_job(
                    job_from_dict,
                    kwargs={
                        "channel_id": job.kwargs.get("channel_id"),
                        "message": f"{response_new_message.clean_content}",
                        "author_id": job.kwargs.get("author_id"),
                    },
                )
                msg += f"**Old message**: {message}\n" f"**New message**: {response_new_message.clean_content}\n"

            else:
                await ctx.channel.send("Type the new date. Type Exit to exit.")

                # TODO: Add timeout
                response_new_date = await bot.wait_for("message", check=check)
                if response_new_date.clean_content == "Exit":
                    return await ctx.channel.send("Exiting...")

                parsed_date = dateparser.parse(
                    f"{response_new_date.clean_content}",
                    settings={
                        "PREFER_DATES_FROM": "future",
                        "TO_TIMEZONE": f"{config_timezone}",
                    },
                )
                date_new = parsed_date.strftime("%Y-%m-%d %H:%M:%S")

                job = scheduler.reschedule_job(job_from_dict, run_date=date_new)

                date_old = job.trigger.run_date.strftime("%Y-%m-%d %H:%M")
                new_time = calc_countdown(job_from_dict)
                msg += f"**Old date**: {date_old} (in {old_time})\n**New date**: {date_new} (in {new_time})"

            await ctx.send(msg)


@slash.subcommand(
    base="remind",
    name="remove",
    description="Remove a reminder",
)
async def remind_remove(ctx: SlashContext):
    """Select reminder from list that you want to remove."""
    # TODO: Reduce complexity

    jobs_dict = await send_list(ctx)

    await ctx.channel.send("Type the corresponding number to the reminder you wish to remove. Type Exit to exit.")

    # Only check for response from the original user and in the correct channel
    def check(m):
        return m.author == ctx.author and m.channel == ctx.channel

    # TODO: Add timeout
    response_message = await bot.wait_for("message", check=check)
    if response_message.clean_content == "Exit":
        return await ctx.channel.send("Exiting...")

    for num, job_from_dict in jobs_dict.items():
        if int(response_message.clean_content) == num:
            job = scheduler.get_job(job_from_dict)
            if job is None:
                await ctx.channel.send(f"No reminder with that ID ({job_from_dict}).")
                return

            channel_id = job.kwargs.get("channel_id")
            channel_name = bot.get_channel(int(channel_id))
            message = job.kwargs.get("message")

            # Only normal reminders have trigger.run_date, cron and
            # interval has next_run_time
            if type(job.trigger) is DateTrigger:
                trigger_time = job.trigger.run_date
            else:
                trigger_time = job.next_run_time

            # Paused reminders returns None
            if trigger_time is None:
                trigger_value = "Paused - can be resumed with '/remind resume'"
            else:
                trigger_value = f'{trigger_time.strftime("%Y-%m-%d %H:%M")} (in {calc_countdown(job)})'

            msg = f"**Removed** {message} in #{channel_name}.\n**Time**: {trigger_value}"

            scheduler.remove_job(job_from_dict)

            await ctx.channel.send(msg)


async def send_list(ctx, skip_datetriggers=False, skip_cron_or_interval=False):
    """Create a list of reminders.

    Args:
        skip_datetriggers: Only show cron jobs and interval reminders.
        skip_cron_or_interval: Only show normal reminders.

    Returns:
        jobs_dict: Dictionary that contains placement in list and job id.
    """
    # TODO: This will fail if the embed is bigger than 6000 characters.
    jobs_dict = {}
    job_number = 0

    embed = discord.Embed(
        colour=discord.Colour.random(),
        title="discord-reminder-bot by TheLovinator#9276",
        description=f"Reminders for {ctx.guild.name}",
        url="https://github.com/TheLovinator1/discord-reminder-bot",
    )
    jobs = scheduler.get_jobs()

    for job in jobs:
        channel_id = job.kwargs.get("channel_id")
        channel_name = bot.get_channel(int(channel_id))

        # Only add reminders from channels in server we run
        # "/reminder list" in

        # Check if channel is in server
        for channel in ctx.guild.channels:
            if channel.id == channel_id:
                if type(job.trigger) is DateTrigger:
                    # Get trigger time for normal reminders
                    trigger_time = job.trigger.run_date

                    # Don't add normal reminders if true
                    if skip_datetriggers:
                        continue
                else:
                    # Get trigger time for cron and interval jobs
                    trigger_time = job.next_run_time

                    # Don't add cron and interval reminders if true
                    if skip_cron_or_interval:
                        continue

                # Paused reminders returns None
                if trigger_time is None:
                    trigger_value = "Paused"
                else:
                    trigger_value = f'{trigger_time.strftime("%Y-%m-%d %H:%M")} (in {calc_countdown(job)})'

                job_number += 1
                jobs_dict[job_number] = job.id
                message = job.kwargs.get("message")

                # Truncate message if it's too long
                field_name = f"{job_number}) {message} in #{channel_name}"
                field_name = field_name[:253] + (field_name[253:] and "...")

                embed.add_field(
                    name=field_name,
                    value=trigger_value,
                    inline=False,
                )

                if job_number == 24:
                    await ctx.send("I haven't added support for showing more than 25 reminders yet 🙃")
                    break

    # The empty embed has 76 characters
    if len(embed) <= 76:
        await ctx.send(f"{ctx.guild.name} has no reminders.")
    else:
        await ctx.send(embed=embed)

    return jobs_dict


@slash.subcommand(base="remind", name="list", description="Show reminders.")
async def remind_list(ctx: SlashContext):
    """Send a list of reminders to Discord."""
    await send_list(ctx)


@slash.subcommand(base="remind", name="pause", description="Pause reminder. For cron or interval.")
async def remind_pause(ctx: SlashContext):
    """Get a list of reminders that you can pause."""
    jobs_dict = await send_list(ctx, skip_datetriggers=True)

    await ctx.channel.send("Type the corresponding number to the reminder you wish to pause. Type Exit to exit.")

    # Only check for response from the original user and in the correct channel
    def check(m):
        return m.author == ctx.author and m.channel == ctx.channel

    # TODO: Add timeout
    response_reminder = await bot.wait_for("message", check=check)
    if response_reminder.clean_content == "Exit":
        return await ctx.channel.send("Exiting...")

    # Pair a number with the job id
    for num, job_from_dict in jobs_dict.items():
        # Check if the response is a number and if it's in the list
        if int(response_reminder.clean_content) == num:
            job = scheduler.get_job(job_from_dict)
            channel_id = job.kwargs.get("channel_id")
            channel_name = bot.get_channel(int(channel_id))
            message = job.kwargs.get("message")

            if type(job.trigger) is DateTrigger:
                # Get trigger time for normal reminders
                trigger_time = job.trigger.run_date
            else:
                # Get trigger time for cron and interval jobs
                trigger_time = job.next_run_time

            # Tell user if he tries to pause a paused reminder
            if trigger_time is None:
                return await ctx.channel.send(f"{message} in #{channel_name} is already paused.")

            trigger_value = f'{trigger_time.strftime("%Y-%m-%d %H:%M")} (in {calc_countdown(job)})'

            msg = f"**Paused** {message} in #{channel_name}.\n**Time**: {trigger_value}"

            scheduler.pause_job(job_from_dict)
            print(f"Paused {job_from_dict} in #{channel_name}")
            await ctx.channel.send(msg)


@slash.subcommand(
    base="remind",
    name="resume",
    description="Resume paused reminder. For cron or interval.",
)
async def remind_resume(ctx: SlashContext):
    """Send a list of reminders to pause to Discord."""
    # TODO: Reduce the complexity of this function
    jobs_dict = await send_list(ctx, skip_datetriggers=True)

    await ctx.channel.send("Type the corresponding number to the reminder you wish to pause. Type Exit to exit.")

    # Only check for response from the original user and in the correct channel
    def check(m):
        return m.author == ctx.author and m.channel == ctx.channel

    # TODO: Add timeout
    response_message = await bot.wait_for("message", check=check)
    if response_message.clean_content == "Exit":
        return await ctx.channel.send("Exiting...")

    for num, job_from_dict in jobs_dict.items():
        if int(response_message.clean_content) == num:
            job = scheduler.get_job(job_from_dict)
            if job is None:
                await ctx.send(f"No reminder with that ID ({job_from_dict}).")
                return

            channel_id = job.kwargs.get("channel_id")
            channel_name = bot.get_channel(int(channel_id))
            message = job.kwargs.get("message")

            try:
                scheduler.resume_job(job_from_dict)
            except Exception as e:
                await ctx.send(e)

            # Only normal reminders have trigger.run_date
            # Cron and interval has next_run_time
            if type(job.trigger) is DateTrigger:
                trigger_time = job.trigger.run_date
            else:
                trigger_time = job.next_run_time

            # Paused reminders returns None
            if trigger_time is None:
                trigger_value = "Paused - can be resumed with '/remind resume'"
            else:
                trigger_value = f'{trigger_time.strftime("%Y-%m-%d %H:%M")} (in {calc_countdown(job)})'

            msg = f"**Resumed** {message} in #{channel_name}.\n**Time**: {trigger_value}\n"

            await ctx.send(msg)


@slash.subcommand(
    base="remind",
    name="add",
    description="Set a reminder.",
    options=[
        create_option(
            name="message_reason",
            description="The message I'm going to send you.",
            option_type=SlashCommandOptionType.STRING,
            required=True,
        ),
        create_option(
            name="message_date",
            description="Time and/or date when you want to get reminded.",
            option_type=SlashCommandOptionType.STRING,
            required=True,
        ),
        create_option(
            name="different_channel",
            description="Send the message to a different channel.",
            option_type=SlashCommandOptionType.CHANNEL,
            required=False,
        ),
    ],
)
async def remind_add(
    ctx: SlashContext,
    message_date: str,
    message_reason: str,
    different_channel: discord.TextChannel = None,
):
    """Add a new reminder. You can add a date and message.

    Args:
        message_date: The date or time that will get parsed.
        message_reason: The message the bot should write when the reminder is triggered.
        different_channel: The channel the reminder should be sent to.
    """
    parsed_date = dateparser.parse(
        f"{message_date}",
        settings={
            "PREFER_DATES_FROM": "future",
            "TO_TIMEZONE": f"{config_timezone}",
        },
    )

    channel_id = ctx.channel.id

    # If we should send the message to a different channel
    if different_channel:
        channel_id = different_channel.id

    run_date = parsed_date.strftime("%Y-%m-%d %H:%M:%S")
    reminder = scheduler.add_job(
        send_to_discord,
        run_date=run_date,
        kwargs={
            "channel_id": channel_id,
            "message": message_reason,
            "author_id": ctx.author_id,
        },
    )

    message = (
        f"Hello {ctx.author.display_name},"
        f" I will notify you in <#{channel_id}> at:\n"
        f"**{run_date}** (in {calc_countdown(reminder)})\n"
        f"With the message:\n**{message_reason}**."
    )

    await ctx.send(message)


@slash.subcommand(
    base="remind",
    name="cron",
    description="Triggers when current time matches all specified time constraints, similarly to the UNIX cron.",
    options=[
        create_option(
            name="message_reason",
            description="The message I'm going to send you.",
            option_type=SlashCommandOptionType.STRING,
            required=True,
        ),
        create_option(
            name="year",
            description="4-digit year. (Example: 2042)",
            option_type=SlashCommandOptionType.STRING,
            required=False,
        ),
        create_option(
            name="month",
            description="Month (1-12)",
            option_type=SlashCommandOptionType.STRING,
            required=False,
        ),
        create_option(
            name="day",
            description="Day of month (1-31)",
            option_type=SlashCommandOptionType.STRING,
            required=False,
        ),
        create_option(
            name="week",
            description="ISO week (1-53)",
            option_type=SlashCommandOptionType.STRING,
            required=False,
        ),
        create_option(
            name="day_of_week",
            description="Number or name of weekday (0-6 or mon,tue,wed,thu,fri,sat,sun). The first weekday is monday.",
            option_type=SlashCommandOptionType.STRING,
            required=False,
        ),
        create_option(
            name="hour",
            description="Hour (0-23)",
            option_type=SlashCommandOptionType.STRING,
            required=False,
        ),
        create_option(
            name="minute",
            description="Minute (0-59)",
            option_type=SlashCommandOptionType.STRING,
            required=False,
        ),
        create_option(
            name="second",
            description="Second (0-59)",
            option_type=SlashCommandOptionType.STRING,
            required=False,
        ),
        create_option(
            name="start_date",
            description="Earliest possible time to trigger on, in the ISO 8601 format. (Example: 2010-10-10 09:30:00)",
            option_type=SlashCommandOptionType.STRING,
            required=False,
        ),
        create_option(
            name="end_date",
            description="Latest possible time to trigger on, in the ISO 8601 format. (Example: 2010-10-10 09:30:00)",
            option_type=SlashCommandOptionType.STRING,
            required=False,
        ),
        create_option(
            name="timezone",
            description="Time zone to use for the date/time calculations (defaults to scheduler timezone)",
            option_type=SlashCommandOptionType.STRING,
            required=False,
        ),
        create_option(
            name="jitter",
            description="Delay the job execution by x seconds at most. Adds a random component to the execution time.",
            option_type=SlashCommandOptionType.INTEGER,
            required=False,
        ),
        create_option(
            name="different_channel",
            description="Send the messages to a different channel.",
            option_type=SlashCommandOptionType.CHANNEL,
            required=False,
        ),
    ],
)
async def remind_cron(
    ctx: SlashContext,
    message_reason: str,
    year: int = None,
    month: int = None,
    day: int = None,
    week: int = None,
    day_of_week: str = None,
    hour: int = None,
    minute: int = None,
    second: int = None,
    start_date: str = None,
    end_date: str = None,
    timezone: str = None,
    jitter: int = None,
    different_channel: discord.TextChannel = None,
):
    """Create new cron job. Works like UNIX cron.

    https://en.wikipedia.org/wiki/Cron
    Args that are None will be defaulted to *.

    Args:
        message_reason: The message the bot should send every time cron job triggers.
        year: 4-digit year.
        month: Month (1-12).
        day: Day of month (1-31).
        week: ISO week (1-53).
        day_of_week: Number or name of weekday (0-6 or mon,tue,wed,thu,fri,sat,sun).
        hour: Hour (0-23).
        minute: Minute (0-59).
        second: Second (0-59).
        start_date: Earliest possible date/time to trigger on (inclusive).
        end_date: Latest possible date/time to trigger on (inclusive).
        timezone: Time zone to use for the date/time calculations Defaults to scheduler timezone.
        jitter: Delay the job execution by jitter seconds at most.

        https://apscheduler.readthedocs.io/en/stable/modules/triggers/cron.html#module-apscheduler.triggers.cron
    """
    channel_id = ctx.channel.id

    # If we should send the message to a different channel
    if different_channel:
        channel_id = different_channel.id

    job = scheduler.add_job(
        send_to_discord,
        "cron",
        year=year,
        month=month,
        day=day,
        week=week,
        day_of_week=day_of_week,
        hour=hour,
        minute=minute,
        second=second,
        start_date=start_date,
        end_date=end_date,
        timezone=timezone,
        jitter=jitter,
        kwargs={
            "channel_id": channel_id,
            "message": message_reason,
            "author_id": ctx.author_id,
        },
    )

    # TODO: Add what arguments we used in the job to the message
    message = (
        f"Hello {ctx.author.display_name},"
        f" I will send messages to <#{channel_id}>.\n"
        f"First run in {calc_countdown(job)} with the message:\n"
        f"**{message_reason}**."
    )
    await ctx.send(message)


@slash.subcommand(
    base="remind",
    name="interval",
    description="Schedules messages to be run periodically, on selected intervals.",
    options=[
        create_option(
            name="message_reason",
            description="The message I'm going to send you.",
            option_type=SlashCommandOptionType.STRING,
            required=True,
        ),
        create_option(
            name="weeks",
            description="Number of weeks to wait",
            option_type=SlashCommandOptionType.INTEGER,
            required=False,
        ),
        create_option(
            name="days",
            description="Number of days to wait",
            option_type=SlashCommandOptionType.INTEGER,
            required=False,
        ),
        create_option(
            name="hours",
            description="Number of hours to wait",
            option_type=SlashCommandOptionType.INTEGER,
            required=False,
        ),
        create_option(
            name="minutes",
            description="Number of minutes to wait",
            option_type=SlashCommandOptionType.INTEGER,
            required=False,
        ),
        create_option(
            name="seconds",
            description="Number of seconds to wait.",
            option_type=SlashCommandOptionType.INTEGER,
            required=False,
        ),
        create_option(
            name="start_date",
            description="When to start, in the ISO 8601 format. (Example: 2010-10-10 09:30:00)",
            option_type=SlashCommandOptionType.STRING,
            required=False,
        ),
        create_option(
            name="end_date",
            description="When to stop, in the ISO 8601 format. (Example: 2014-06-15 11:00:00)",
            option_type=SlashCommandOptionType.STRING,
            required=False,
        ),
        create_option(
            name="timezone",
            description="Time zone to use for the date/time calculations",
            option_type=SlashCommandOptionType.STRING,
            required=False,
        ),
        create_option(
            name="jitter",
            description="Delay the job execution by x seconds at most. Adds a random component to the execution time.",
            option_type=SlashCommandOptionType.INTEGER,
            required=False,
        ),
        create_option(
            name="different_channel",
            description="Send the messages to a different channel.",
            option_type=SlashCommandOptionType.CHANNEL,
            required=False,
        ),
    ],
)
async def remind_interval(
    ctx: SlashContext,
    message_reason: str,
    weeks: int = 0,
    days: int = 0,
    hours: int = 0,
    minutes: int = 0,
    seconds: int = 0,
    start_date: str = None,
    end_date: str = None,
    timezone: str = None,
    jitter: int = None,
    different_channel: discord.TextChannel = None,
):
    """Create new reminder that triggers based on a interval.

    Args:
        message_reason: The message we should write when triggered.
        weeks: Number of weeks to wait.
        days: Number of days to wait.
        hours: Number of hours to wait.
        minutes: Number of minutes to wait.
        seconds: Number of seconds to wait.
        start_date: Starting point for the interval calculation.
        end_date: Latest possible date/time to trigger on.
        timezone: Time zone to use for the date/time calculations.
        jitter: Delay the job execution by jitter seconds at most.
    """

    channel_id = different_channel.id if different_channel else ctx.channel.id

    job = scheduler.add_job(
        send_to_discord,
        "interval",
        weeks=weeks,
        days=days,
        hours=hours,
        minutes=minutes,
        seconds=seconds,
        start_date=start_date,
        end_date=end_date,
        timezone=timezone,
        jitter=jitter,
        kwargs={
            "channel_id": channel_id,
            "message": message_reason,
            "author_id": ctx.author_id,
        },
    )

    # TODO: Add what arguments we used in the job to the message
    message = (
        f"Hello {ctx.author.display_name}, I will send messages to <#{channel_id}>.\n"
        f"First run in {calc_countdown(job)} with the message:\n"
        f"**{message_reason}**."
    )

    await ctx.send(message)


async def send_to_discord(channel_id: int, message: str, author_id: int):
    """Send a message to Discord.

    Args:
        channel_id: The Discord channel ID.
        message: The message.
        author_id: User we should ping.
    """
    # TODO: Check if channel exists.
    channel = bot.get_channel(int(channel_id))
    await channel.send(f"<@{author_id}>\n{message}")


def start():
    """Start scheduler and log in to Discord."""
    # TODO: Add how many reminders are scheduled.
    # TODO: Make backup of jobs.sqlite before running the bot.
    logging.basicConfig(level=logging.getLevelName(log_level))
    logging.info(
        f"\nsqlite_location = {sqlite_location}\n"
        f"config_timezone = {config_timezone}\n"
        f"bot_token = {bot_token}\n"
        f"log_level = {log_level}"
    )

    scheduler.start()
    bot.run(bot_token)


if __name__ == "__main__":
    start()