//! Formatting + small browser helpers.

use chrono::{DateTime, Utc};

pub fn format_size(bytes: u64) -> String {
    const UNITS: [&str; 5] = ["B", "KB", "MB", "GB", "TB"];
    let mut v = bytes as f64;
    let mut i = 0;
    while v >= 1024.0 && i < UNITS.len() - 1 {
        v /= 1024.0;
        i += 1;
    }
    if i == 0 {
        format!("{bytes} B")
    } else {
        format!("{v:.1} {}", UNITS[i])
    }
}

pub fn format_date(rfc3339: &str) -> String {
    match DateTime::parse_from_rfc3339(rfc3339) {
        Ok(dt) => dt.with_timezone(&Utc).format("%Y-%m-%d %H:%M").to_string(),
        Err(_) => rfc3339.to_string(),
    }
}

pub fn storage_get(key: &str) -> Option<String> {
    let w = web_sys::window()?;
    let storage_opt = w.local_storage().ok()?;
    let storage = storage_opt.as_ref()?;
    storage.get_item(key).ok().flatten()
}

pub fn storage_set(key: &str, value: &str) {
    if let Some(s) = web_sys::window().and_then(|w| w.local_storage().ok().flatten()) {
        let _ = s.set_item(key, value);
    }
}

#[derive(Clone, Copy, PartialEq, Debug)]
pub enum ViewMode {
    Grid,
    List,
}

impl ViewMode {
    const KEY: &'static str = "fbng.view";

    pub fn load() -> Self {
        match storage_get(Self::KEY).as_deref() {
            Some("list") => ViewMode::List,
            _ => ViewMode::Grid,
        }
    }

    pub fn save(self) {
        storage_set(Self::KEY, if self == ViewMode::List { "list" } else { "grid" });
    }
}