use std::{collections::HashMap, path::Path, str::FromStr};

use eyre::{Context, Result};
use serde::Deserialize;

#[derive(Debug, Default)]
pub struct Config {
    pub datasets: Vec<Dataset>,
    pub schedules: Vec<Schedule>,
}

impl Config {
    pub fn dataset(&self, name: &str) -> Option<&Dataset> {
        self.datasets.iter().find(|d| d.name == name)
    }

    pub fn tag(&self, tag: &str) -> Option<&Schedule> {
        self.schedules.iter().find(|s| s.tag == tag)
    }
}

#[derive(Debug, Clone)]
pub struct Dataset {
    pub name: String,
    pub schedules: Vec<String>,
    pub recursive: bool,
}

impl Dataset {
    pub fn has_tag(&self, tag: &str) -> bool {
        self.schedules.iter().any(|s| s == tag)
    }
}

#[derive(Debug, Clone)]
pub struct Schedule {
    pub tag: String,
    pub cron: cron::Schedule,
    pub keep: usize,
}

#[derive(Debug, Deserialize)]
struct TomlConfig {
    dataset: HashMap<String, TomlDataset>,
    schedule: HashMap<String, TomlSchedule>,
}

#[derive(Debug, Deserialize)]
struct TomlDataset {
    recursive: Option<bool>,
    schedules: Vec<String>,
}

#[derive(Debug, Deserialize)]
struct TomlSchedule {
    cron: String,
    keep: usize,
}

pub fn read(path: &Path) -> Result<Config> {
    let content = std::fs::read_to_string(path)?;
    let config = toml::from_str::<TomlConfig>(&content)?;

    let mut datasets = Vec::new();
    let mut schedules = Vec::new();

    for (name, dataset) in config.dataset {
        let schedules = dataset.schedules;
        let recursive = dataset.recursive;

        datasets.push(Dataset {
            name,
            schedules,
            recursive: recursive.unwrap_or_default(),
        });
    }

    for (name, schedule) in config.schedule {
        let cron = cron::Schedule::from_str(&schedule.cron)
            .with_context(|| format!("parsing cron schedule: '{}'", &schedule.cron))?;
        let keep = schedule.keep;

        schedules.push(Schedule { tag: name, cron, keep });
    }

    Ok(Config {
        datasets,
        schedules,
    })
}