use std::fs;
use std::path::Path;
use std::process::Command;

use chrono::{Days, NaiveDate, NaiveDateTime, NaiveTime, TimeZone, Utc};
use chrono_tz::Tz;

use crate::config::Settings;
use crate::error::StreamdError;
use crate::models::RepositoryConfiguration;
use crate::timesheet::load_repository_config;

use super::load_markdown_shards;

pub fn run(date: Option<String>) -> Result<(), StreamdError> {
    let settings = Settings::load()?;
    let base_folder = Path::new(&settings.base_folder);

    let repo_config = load_repository_config(base_folder)?;
    let tz: Tz = repo_config
        .timezone
        .as_deref()
        .and_then(|s| s.parse().ok())
        .unwrap_or(chrono_tz::UTC);

    let target_date: NaiveDate = match date {
        Some(s) => NaiveDate::parse_from_str(&s, "%Y%m%d").map_err(|_| {
            StreamdError::ConfigError("Invalid date format, expected YYYYMMDD".into())
        })?,
        None => Utc::now().with_timezone(&tz).date_naive(),
    };

    let day_start = tz
        .from_local_datetime(&NaiveDateTime::new(target_date, NaiveTime::MIN))
        .earliest()
        .unwrap()
        .with_timezone(&Utc);
    let day_end = tz
        .from_local_datetime(&NaiveDateTime::new(
            target_date + Days::new(1),
            NaiveTime::MIN,
        ))
        .earliest()
        .unwrap()
        .with_timezone(&Utc);

    let all_shards = load_markdown_shards(base_folder, &RepositoryConfiguration::new(), tz)?;
    let mut daily_shards: Vec<_> = all_shards
        .into_iter()
        .filter(|s| {
            s.location
                .get("file_type")
                .map(|v| v == "daily")
                .unwrap_or(false)
                && s.moment >= day_start
                && s.moment < day_end
        })
        .collect();
    daily_shards.sort_by_key(|s| s.moment);

    let editor = std::env::var("EDITOR").unwrap_or_else(|_| "vi".to_string());

    if let Some(shard) = daily_shards.first() {
        let file_path = shard.location.get("file").unwrap();
        Command::new(&editor).arg(file_path).status()?;
    } else {
        let now_local = Utc::now().with_timezone(&tz);
        let file_name = now_local.format("%Y%m%d-%H%M%S_daily.md").to_string();
        let file_path = base_folder.join(&file_name);
        fs::write(&file_path, "# ")?;
        Command::new(&editor).arg(&file_path).status()?;
        println!("Created {}", file_name);
    }

    Ok(())
}