import logging
import random

import discord
from discord.ext import commands

from bot.constants import Channels, Colours, ERROR_REPLIES, Emojis, Tokens, WHITELISTED_CHANNELS
from bot.utils.decorators import override_in_channel

log = logging.getLogger(__name__)

BAD_RESPONSE = {
    404: "Issue/pull request not located! Please enter a valid number!",
    403: "Rate limit has been hit! Please try again later!"
}

MAX_REQUESTS = 10

REQUEST_HEADERS = dict()
if GITHUB_TOKEN := Tokens.github:
    REQUEST_HEADERS["Authorization"] = f"token {GITHUB_TOKEN}"


class Issues(commands.Cog):
    """Cog that allows users to retrieve issues from GitHub."""

    def __init__(self, bot: commands.Bot):
        self.bot = bot

    @commands.command(aliases=("pr",))
    @override_in_channel(WHITELISTED_CHANNELS + (Channels.dev_contrib, Channels.dev_branding))
    async def issue(
        self,
        ctx: commands.Context,
        numbers: commands.Greedy[int],
        repository: str = "seasonalbot",
        user: str = "python-discord"
    ) -> None:
        """Command to retrieve issue(s) from a GitHub repository."""
        links = []
        numbers = set(numbers)

        if not numbers:
            await ctx.invoke(self.bot.get_command('help'), 'issue')
            return

        if len(numbers) > MAX_REQUESTS:
            embed = discord.Embed(
                title=random.choice(ERROR_REPLIES),
                color=Colours.soft_red,
                description=f"Too many issues/PRs! (maximum of {MAX_REQUESTS})"
            )
            await ctx.send(embed=embed)
            return

        for number in set(numbers):
            # Convert from list to set to remove duplicates, if any.
            url = f"https://api.github.com/repos/{user}/{repository}/issues/{number}"
            merge_url = f"https://api.github.com/repos/{user}/{repository}/pulls/{number}/merge"

            log.trace(f"Querying GH issues API: {url}")
            async with self.bot.http_session.get(url, headers=REQUEST_HEADERS) as r:
                json_data = await r.json()

            if r.status in BAD_RESPONSE:
                log.warning(f"Received response {r.status} from: {url}")
                return await ctx.send(f"[{str(r.status)}] #{number} {BAD_RESPONSE.get(r.status)}")

            # The initial API request is made to the issues API endpoint, which will return information
            # if the issue or PR is present. However, the scope of information returned for PRs differs
            # from issues: if the 'issues' key is present in the response then we can pull the data we
            # need from the initial API call.
            if "issues" in json_data.get("html_url"):
                if json_data.get("state") == "open":
                    icon_url = Emojis.issue
                else:
                    icon_url = Emojis.issue_closed

            # If the 'issues' key is not contained in the API response and there is no error code, then
            # we know that a PR has been requested and a call to the pulls API endpoint is necessary
            # to get the desired information for the PR.
            else:
                log.trace(f"PR provided, querying GH pulls API for additional information: {merge_url}")
                async with self.bot.http_session.get(merge_url) as m:
                    if json_data.get("state") == "open":
                        icon_url = Emojis.pull_request
                    # When the status is 204 this means that the state of the PR is merged
                    elif m.status == 204:
                        icon_url = Emojis.merge
                    else:
                        icon_url = Emojis.pull_request_closed

            issue_url = json_data.get("html_url")
            links.append([icon_url, f"[{repository}] #{number} {json_data.get('title')}", issue_url])

        # Issue/PR format: emoji to show if open/closed/merged, number and the title as a singular link.
        description_list = ["{0} [{1}]({2})".format(*link) for link in links]
        resp = discord.Embed(
            colour=Colours.bright_green,
            description='\n'.join(description_list)
        )

        resp.set_author(name="GitHub", url=f"https://github.com/{user}/{repository}")
        await ctx.send(embed=resp)


def setup(bot: commands.Bot) -> None:
    """Cog Retrieves Issues From Github."""
    bot.add_cog(Issues(bot))