import csv
import functools
import itertools
import subprocess
import time
from datetime import datetime
from enum import Enum
from io import StringIO
from typing import List, Optional, Sequence, Tuple

import cachetools.func
import httpx
import typer
from pydantic import BaseModel, BaseSettings, Field
from tabulate import tabulate as tab
from tabulate import tabulate_formats

from fedmon import appname

app = typer.Typer()
tabulate_formats = set(tabulate_formats)

AllowedFormat = Enum(
    "AllowedFormat", {"json": "json", "csv": "csv", **{v: v for v in tabulate_formats}}
)


class AppConfig(BaseSettings):
    base_url: str = "https://analytics.usa.gov/data/live/all-pages-realtime.csv"
    poll: int = 10 * 60

    class Config:
        case_sensitive = False
        env_prefix = "fedmon_"


config = AppConfig()


@cachetools.func.ttl_cache(ttl=config.poll)
def get_data(base_url: str) -> Tuple[str]:
    with httpx.Client() as client:
        resp = client.get(base_url)
        resp.raise_for_status()
    return tuple(resp.content.decode().splitlines())


class FedSite(BaseModel):
    datetime: str = Field(default_factory=lambda: datetime.now().isoformat())
    active_visitors: Optional[int]
    page_title: str
    page: str

    class Config:
        frozen = True


class Summary(BaseModel):
    sites: Sequence[FedSite]


@functools.lru_cache()
def parse_data(data: Tuple[str]) -> Tuple[FedSite]:
    return tuple(FedSite.parse_obj(line) for line in csv.DictReader(data))


@functools.lru_cache()
def analyze_data(data: Tuple[FedSite], to_ignore: List[str]) -> Summary:
    if to_ignore is None:
        to_ignore = []
    usps = {x for x in data if "tools.usps.com" in x.page}
    usps_visitors = max(x.active_visitors for x in usps)
    hot = tuple(
        sorted(
            (
                x
                for x in data
                if x.active_visitors >= usps_visitors
                and x not in usps
                and not any(i in x.page for i in to_ignore)
            ),
            key=lambda x: x.active_visitors,
        )
    )
    return Summary(sites=hot)


def format_response(summary: Summary, format: AllowedFormat, count: int) -> str:
    if format == AllowedFormat.json:
        return summary.json(indent=4)
    elif format == AllowedFormat.csv:
        data = StringIO()
        to_write = summary.dict()["sites"]
        headers = FedSite.schema()["properties"].keys()
        writer = csv.DictWriter(data, fieldnames=headers)
        if count == 0:
            writer.writeheader()
        writer.writerows(to_write)
        return data.getvalue()
    else:
        data = summary.dict()["sites"]
        for site in data:
            site["active_visitors"] = str(site["active_visitors"]).rjust(19)
            site["page_title"] = site["page_title"].rjust(25)
            site["page"] = site["page"].rjust(26)
        if count == 0:
            return tab(data, tablefmt=format.value, headers="keys")
        else:
            return tab(data, tablefmt=format.value)


def notify(summary: Summary, counter) -> None:
    try:
        subprocess.check_call(
            [
                "notify-send",
                appname,
                format_response(summary, AllowedFormat.json, next(counter)),
            ]
        )
    except subprocess.CalledProcessError as e:
        typer.echo(e, err=True)


@app.command()
def main(
    format: AllowedFormat = typer.Option(
        default="json", show_choices=True, help="The format to display results in."
    ),
    send_notification: bool = typer.Option(
        default=False,
        help="If set, use `notify-send` to raise a desktop notification, if available.",
    ),
    ignore: Optional[List[str]] = typer.Option(None),
):
    prev = None
    counter = itertools.count()
    while True:
        try:
            data = get_data(config.base_url)
            data = parse_data(data)
            summary = analyze_data(data, to_ignore=ignore)
            if summary != prev:
                if summary.sites:
                    c = next(counter)
                    typer.echo(format_response(summary, format, c))
                    if send_notification:
                        notify(summary, c)
                prev = summary
        except (httpx.ConnectError, httpx.ReadTimeout) as e:
            typer.echo(e, err=True)
        finally:
            time.sleep(config.poll)