// Shared utilities

use crate::store;

use std::fs;
use std::path::PathBuf;

/// Ensure a subdirectory of the memory dir exists and return its path.
pub fn memory_subdir(name: &str) -> Result<PathBuf, String> {
    let dir = store::memory_dir().join(name);
    fs::create_dir_all(&dir)
        .map_err(|e| format!("create {}: {}", dir.display(), e))?;
    Ok(dir)
}

/// Truncate text to `max_len` bytes at a char boundary, appending `suffix`.
/// Returns the original string if it's already short enough.
pub fn truncate(text: &str, max_len: usize, suffix: &str) -> String {
    if text.len() <= max_len {
        text.to_string()
    } else {
        let end = text.floor_char_boundary(max_len);
        format!("{}{}", &text[..end], suffix)
    }
}

/// Take the first `n` chars from a string.
pub fn first_n_chars(s: &str, n: usize) -> String {
    s.chars().take(n).collect()
}

/// Parse a timestamp string to unix epoch seconds.
/// Handles: "2026-03-05T19:56:00", "2026-03-05T19:56", "2026-03-05 19:56:00", "2026-03-05 19:56"
pub fn parse_timestamp_to_epoch(ts: &str) -> Option<i64> {
    use chrono::{Local, NaiveDateTime, TimeZone};
    let formats = ["%Y-%m-%dT%H:%M:%S", "%Y-%m-%dT%H:%M", "%Y-%m-%d %H:%M:%S", "%Y-%m-%d %H:%M"];
    for fmt in &formats {
        if let Ok(ndt) = NaiveDateTime::parse_from_str(ts, fmt) {
            if let Some(dt) = Local.from_local_datetime(&ndt).earliest() {
                return Some(dt.timestamp());
            }
        }
    }
    None
}