use std::convert::TryFrom;
use std::io::{BufRead, Write};

use clap::ArgMatches;
use chrono::{DateTime, Utc, Local, Timelike};
use regex::Regex;

use crate::error::{Result, Error};
use crate::database::Database;
use crate::formatters::Formatter;
use crate::timeparse::parse_time;
use crate::regex::parse_regex;
use crate::io::Streams;

use super::{Command, Facts, display::{Sheet, entries_for_display}};

#[derive(Default)]
pub struct Args {
    ids: bool,
    end: Option<DateTime<Utc>>,
    format: Option<Formatter>,
    grep: Option<Regex>,
    sheet: Option<Sheet>,
}

impl<'a> TryFrom<&'a ArgMatches> for Args {
    type Error = Error;

    fn try_from(matches: &'a ArgMatches) -> Result<Args> {
        Ok(Args {
            ids: matches.is_present("ids"),
            end: matches.value_of("end").map(parse_time).transpose()?,
            format: matches.value_of("format").map(|v| v.parse()).transpose()?,
            grep: matches.value_of("grep").map(parse_regex).transpose()?,
            sheet: matches.value_of("sheet").map(|s| s.parse()).transpose()?,
        })
    }
}

pub struct TodayCommand { }

impl<'a> Command<'a> for TodayCommand {
    type Args = Args;

    fn handle<D, I, O, E>(args: Self::Args, streams: &mut Streams<D, I, O, E>, facts: &Facts) -> Result<()>
    where
        D: Database,
        I: BufRead,
        O: Write,
        E: Write,
    {
        let start = Some(facts.now
            .with_timezone(&Local)
            .with_hour(0).unwrap()
            .with_minute(0).unwrap()
            .with_second(0).unwrap()
            .with_nanosecond(0).unwrap()
            .with_timezone(&Utc));

        entries_for_display(
            start,
            args.end,
            args.sheet,
            streams,
            args.format.unwrap_or_else(|| facts.config.commands.today.default_formatter.as_ref().unwrap_or(&facts.config.default_formatter).clone()),
            args.ids,
            args.grep,
            facts
        )
    }
}

#[cfg(test)]
mod tests {
    use chrono::TimeZone;

    use crate::config::{Config, CommandsSettings, BaseCommandSettings};

    use super::*;

    #[test]
    fn respect_default_formatter() {
        std::env::set_var("TZ", "CST+6");

        let args = Default::default();
        let mut streams = Streams::fake(b"");
        let facts = Facts::new().with_config(Config {
            default_formatter: Formatter::Ids,
            ..Default::default()
        }).with_now(Utc.with_ymd_and_hms(2021, 6, 30, 11, 0, 0).unwrap());

        streams.db.entry_insert(Utc.with_ymd_and_hms(2021, 6, 30, 10, 0, 0).unwrap(), None, Some("hola".into()), "default").unwrap();
        streams.db.entry_insert(Utc.with_ymd_and_hms(2021, 6, 30, 10, 10, 0).unwrap(), None, Some("hola".into()), "default").unwrap();

        TodayCommand::handle(args, &mut streams, &facts).unwrap();

        assert_eq!(&String::from_utf8_lossy(&streams.out), "1 2\n");
        assert_eq!(String::from_utf8_lossy(&streams.err), "");
    }

    #[test]
    fn respect_command_default_formatter() {
        std::env::set_var("TZ", "CST+6");

        let args = Default::default();
        let mut streams = Streams::fake(b"");
        let facts = Facts::new().with_config(Config {
            commands: CommandsSettings {
                today: BaseCommandSettings {
                    default_formatter: Some(Formatter::Ids),
                },
                ..Default::default()
            },
            ..Default::default()
        }).with_now(Utc.with_ymd_and_hms(2021, 6, 30, 11, 0, 0).unwrap());

        streams.db.entry_insert(Utc.with_ymd_and_hms(2021, 6, 30, 10, 0, 0).unwrap(), None, Some("hola".into()), "default").unwrap();
        streams.db.entry_insert(Utc.with_ymd_and_hms(2021, 6, 30, 10, 10, 0).unwrap(), None, Some("hola".into()), "default").unwrap();

        TodayCommand::handle(args, &mut streams, &facts).unwrap();

        assert_eq!(&String::from_utf8_lossy(&streams.out), "1 2\n");
        assert_eq!(String::from_utf8_lossy(&streams.err), "");
    }
}