use std::io::Write;
use std::convert::TryFrom;

use chrono::{DateTime, Utc};
use clap::ArgMatches;

use crate::database::Database;
use crate::config::Config;
use crate::error::{Error, Result};
use crate::timeparse::parse_time;
use crate::old::{time_or_warning, warn_if_needed};

use super::Command;

#[derive(Default)]
pub struct Args {
    at: Option<DateTime<Utc>>,
}

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

    fn try_from(matches: &'a ArgMatches) -> Result<Args> {
        Ok(Args {
            at: matches.value_of("at").map(|s| parse_time(s)).transpose()?,
        })
    }
}

pub struct OutCommand{}

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

    fn handle<D: Database, O: Write, E: Write>(args: Self::Args, db: &mut D, out: &mut O, err: &mut E, _config: &Config, now: DateTime<Utc>) -> Result<()> {
        let end = args.at.unwrap_or(now);
        let sheet = db.current_sheet()?.unwrap_or_else(|| "default".into());

        let (end, needs_warning) = time_or_warning(end, db)?;

        if let Some(entry) = db.running_entry(&sheet)? {
            writeln!(out, "Checked out of sheet \"{}\".", sheet)?;

            db.entry_update(entry.id, entry.start, Some(end), entry.note, &entry.sheet)?;
        } else {
            writeln!(out, "No running entry on sheet \"{}\".", sheet)?;
        }

        warn_if_needed(err, needs_warning)?;

        Ok(())
    }
}

#[cfg(test)]
mod tests {
    use ansi_term::Color::Yellow;
    use pretty_assertions::assert_eq;
    use chrono::{TimeZone, Local};

    use crate::test_utils::Ps;
    use crate::database::SqliteDatabase;

    use super::*;

    #[test]
    fn finishes_entry() {
        let mut db = SqliteDatabase::from_memory().unwrap();
        let args = Default::default();
        let mut out = Vec::new();
        let mut err = Vec::new();
        let now = Utc::now();

        db.init().unwrap();

        db.entry_insert(now, None, None, "default").unwrap();

        OutCommand::handle(args, &mut db, &mut out, &mut err, &Default::default(), now).unwrap();

        let e = db.entries_full(None, None).unwrap().into_iter().next().unwrap();

        assert_eq!(e.end, Some(now));

        assert_eq!(Ps(&String::from_utf8_lossy(&out)), Ps("Checked out of sheet \"default\".\n"));
        assert_eq!(Ps(&String::from_utf8_lossy(&err)), Ps(""));
    }

    #[test]
    fn tells_if_no_running_entry() {
        let mut db = SqliteDatabase::from_memory().unwrap();
        let args = Default::default();
        let mut out = Vec::new();
        let mut err = Vec::new();
        let now = Utc::now();

        db.init().unwrap();

        db.entry_insert(now, None, None, "non-default").unwrap();

        OutCommand::handle(args, &mut db, &mut out, &mut err, &Default::default(), now).unwrap();

        assert_eq!(Ps(&String::from_utf8_lossy(&out)), Ps("No running entry on sheet \"default\".\n"));
        assert_eq!(Ps(&String::from_utf8_lossy(&err)), Ps(""));
    }

    #[test]
    fn warns_if_old_database() {
        let mut db = SqliteDatabase::from_memory().unwrap();
        let args = Default::default();
        let mut out = Vec::new();
        let mut err = Vec::new();
        let now = Utc::now();

        db.init_old().unwrap();

        db.entry_insert(now, None, None, "default").unwrap();

        OutCommand::handle(args, &mut db, &mut out, &mut err, &Default::default(), now).unwrap();

        let e = db.entries_full(None, None).unwrap().into_iter().next().unwrap();

        assert_eq!(e.end, Some(Utc.from_utc_datetime(&now.with_timezone(&Local).naive_local())));

        assert_eq!(Ps(&String::from_utf8_lossy(&out)), Ps("Checked out of sheet \"default\".\n"));
        assert_eq!(Ps(&String::from_utf8_lossy(&err)), Ps(&format!(
            "{} You are using the old timetrap format, it is advised that \
            you update your database using t migrate\n",
            Yellow.bold().paint("[WARNING]"))));
    }
}