extern crate ansi_term;

use self::ansi_term::Colour::Fixed;

static UNITS: [char; 4] = ['T', 'G', 'M', 'K'];

pub fn draw_it(permissions: bool, base_dirs: Vec<&str>, to_display: Vec<(String, u64)>) -> () {
    if !permissions {
        eprintln!("Did not have permissions for all directories");
    }

    for f in base_dirs {
        display_node(f, &to_display, true, "")
    }
}

fn get_size(nodes: &Vec<(String, u64)>, node_to_print: String) -> Option<u64> {
    for &(ref k, ref v) in nodes.iter() {
        if *k == node_to_print {
            return Some(*v);
        }
    }
    None
}

fn display_node<S: Into<String>>(
    node_to_print: &str,
    to_display: &Vec<(String, u64)>,
    is_biggest: bool,
    indentation_str: S,
) {
    let mut is = indentation_str.into();
    let size = get_size(to_display, node_to_print.to_string());
    match size {
        None => println!("Can not find path: {}", node_to_print),
        Some(size) => {
            print_this_node(node_to_print, size, is_biggest, is.as_ref());

            is = is.replace("└─┬", "  ");
            is = is.replace("└──", "  ");
            is = is.replace("├──", "│ ");
            is = is.replace("├─┬", "│ ");

            let printable_node_slashes = node_to_print.matches('/').count();

            let mut num_siblings = to_display.iter().fold(0, |a, b| {
                if b.0.starts_with(node_to_print)
                    && b.0.matches('/').count() == printable_node_slashes + 1
                {
                    a + 1
                } else {
                    a
                }
            });

            let mut is_biggest = true;
            for &(ref k, _) in to_display.iter() {
                if k.starts_with(node_to_print)
                    && k.matches('/').count() == printable_node_slashes + 1
                {
                    num_siblings -= 1;

                    let mut has_children = false;
                    for &(ref k2, _) in to_display.iter() {
                        let kk :&str = k.as_ref();
                        if k2.starts_with(kk)
                            && k2.matches('/').count() == printable_node_slashes + 2
                        {
                            has_children = true;
                        }
                    }

                    display_node(
                        &k,
                        to_display,
                        is_biggest,
                        is.to_string() + get_tree_chars(num_siblings, has_children),
                    );
                    is_biggest = false;
                }
            }
        }
    }
}

fn get_tree_chars(num_siblings: u64, has_children: bool) -> &'static str {
    if num_siblings == 0 {
        if has_children {
            "└─┬"
        } else {
            "└──"
        }
    } else {
        if has_children {
            "├─┬"
        } else {
            "├──"
        }
    }
}
fn print_this_node(node_name: &str, size: u64, is_biggest: bool, indentation: &str) {
    let pretty_size = format!("{:>5}", human_readable_number(size),);
    println!(
        "{}",
        format_string(node_name, is_biggest, pretty_size.as_ref(), indentation)
    )
}

pub fn format_string(dir_name: &str, is_biggest: bool, size: &str, indentation: &str) -> String {
    format!(
        "{} {} {}",
        if is_biggest {
            Fixed(196).paint(size)
        } else {
            Fixed(7).paint(size)
        },
        indentation,
        dir_name,
    )
}

fn human_readable_number(size: u64) -> String {
    for (i, u) in UNITS.iter().enumerate() {
        let marker = 1024u64.pow((UNITS.len() - i) as u32);
        if size >= marker {
            if size / marker < 10 {
                return format!("{:.1}{}", (size as f32 / marker as f32), u);
            } else {
                return format!("{}{}", (size / marker), u);
            }
        }
    }
    return format!("{}B", size);
}

mod tests {
    #[allow(unused_imports)]
    use super::*;

    #[test]
    fn test_human_readable_number() {
        assert_eq!(human_readable_number(1), "1B");
        assert_eq!(human_readable_number(956), "956B");
        assert_eq!(human_readable_number(1004), "1004B");
        assert_eq!(human_readable_number(1024), "1.0K");
        assert_eq!(human_readable_number(1536), "1.5K");
        assert_eq!(human_readable_number(1024 * 512), "512K");
        assert_eq!(human_readable_number(1024 * 1024), "1.0M");
        assert_eq!(human_readable_number(1024 * 1024 * 1024 - 1), "1023M");
        assert_eq!(human_readable_number(1024 * 1024 * 1024 * 20), "20G");
        assert_eq!(human_readable_number(1024 * 1024 * 1024 * 1024), "1.0T");
    }
}