use crate::app_config::AppConfig;
use crate::devices::device::DeviceId;
use crate::logs::log_entry::LogEntry;
use crate::logs::severity::LogSeverity;
use crate::utils::time_utils::{curr_day_number, time_secs};
use fs4::fs_std::FileExt;
use std::fs::OpenOptions;
use std::io::{Seek, SeekFrom, Write};

pub fn save_log(
    device: Option<&DeviceId>,
    severity: LogSeverity,
    message: String,
) -> anyhow::Result<()> {
    let log_path = AppConfig::get().log_of_day(curr_day_number());

    let mut file = OpenOptions::new()
        .append(true)
        .create(true)
        .open(&log_path)?;

    file.lock_exclusive()?;
    file.seek(SeekFrom::End(0))?;
    file.write_all(
        format!(
            "{}\n",
            (LogEntry {
                device_id: device.cloned(),
                time: time_secs(),
                severity,
                message,
            })
            .serialize()?
        )
        .as_bytes(),
    )?;
    file.flush()?;
    file.unlock()?;

    Ok(())
}

/// Make a logs extraction
pub fn get_logs(day: u64) -> anyhow::Result<Vec<LogEntry>> {
    let file = AppConfig::get().log_of_day(day);

    if !file.exists() {
        return Ok(Vec::new());
    }

    let content = std::fs::read_to_string(file)?
        .split('\n')
        .filter(|l| !l.is_empty())
        .map(serde_json::from_str)
        .collect::<Result<Vec<_>, _>>()?;

    Ok(content)
}