///
/// Macros
///
#[macro_export]
macro_rules! err {
    ($err:expr, $err_desc:expr, $msg:expr) => {
        err_json!(json!({
          "error": $err,
          "error_description": $err_desc,
          "ErrorModel": {
            "Message": $msg,
            "ValidationErrors": null,
            "Object": "error"
          }
        }))
    };
    ($msg:expr) => { err!("default_error", "default_error_description", $msg) }
}

#[macro_export]
macro_rules! err_json {
    ($expr:expr) => {{
        println!("ERROR: {}", $expr);
        return Err($crate::rocket::response::status::BadRequest(Some($crate::rocket_contrib::Json($expr))));
    }}
}

#[macro_export]
macro_rules! err_handler {
    ($expr:expr) => {{
        println!("ERROR: {}", $expr);
        return $crate::rocket::Outcome::Failure(($crate::rocket::http::Status::Unauthorized, $expr));
    }}
}

///
/// File handling
///

use std::path::Path;
use std::io::Read;
use std::fs::{self, File};

pub fn file_exists(path: &str) -> bool {
    Path::new(path).exists()
}

pub fn read_file(path: &str) -> Result<Vec<u8>, String> {
    let mut file = File::open(Path::new(path))
        .map_err(|e| format!("Error opening file: {}", e))?;

    let mut contents: Vec<u8> = Vec::new();

    file.read_to_end(&mut contents)
        .map_err(|e| format!("Error reading file: {}", e))?;

    Ok(contents)
}

pub fn delete_file(path: &str) -> bool {
    let res = fs::remove_file(path).is_ok();

    if let Some(parent) = Path::new(path).parent() {
        // If the directory isn't empty, this returns an error, which we ignore
        // We only want to delete the folder if it's empty
        fs::remove_dir(parent).ok();
    }

    res
}


const UNITS: [&str; 6] = ["bytes", "KB", "MB", "GB", "TB", "PB"];

pub fn get_display_size(size: i32) -> String {
    let mut size = size as f64;
    let mut unit_counter = 0;

    loop {
        if size > 1024. {
            size /= 1024.;
            unit_counter += 1;
        } else {
            break;
        }
    };

    // Round to two decimals
    size = (size * 100.).round() / 100.;
    format!("{} {}", size, UNITS[unit_counter])
}


///
/// String util methods
///

use std::str::FromStr;

pub fn upcase_first(s: &str) -> String {
    let mut c = s.chars();
    match c.next() {
        None => String::new(),
        Some(f) => f.to_uppercase().collect::<String>() + c.as_str(),
    }
}

pub fn parse_option_string<S, T>(string: Option<S>) -> Option<T> where S: AsRef<str>, T: FromStr {
    if let Some(Ok(value)) = string.map(|s| s.as_ref().parse::<T>()) {
        Some(value)
    } else {
        None
    }
}

///
/// Date util methods
///

use chrono::NaiveDateTime;

const DATETIME_FORMAT: &str = "%Y-%m-%dT%H:%M:%S%.6fZ";

pub fn format_date(date: &NaiveDateTime) -> String {
    date.format(DATETIME_FORMAT).to_string()
}

///
/// Deserialization methods
///

use std::collections::BTreeMap as Map;

use serde::de::{self, Deserialize, DeserializeOwned, Deserializer};
use serde_json::Value;

/// https://github.com/serde-rs/serde/issues/586
pub fn upcase_deserialize<'de, T, D>(deserializer: D) -> Result<T, D::Error>
    where T: DeserializeOwned,
          D: Deserializer<'de>
{
    let map = Map::<String, Value>::deserialize(deserializer)?;
    let lower = map.into_iter().map(|(k, v)| (upcase_first(&k), v)).collect();
    T::deserialize(Value::Object(lower)).map_err(de::Error::custom)
}

#[derive(PartialEq, Serialize, Deserialize)]
pub struct UpCase<T: DeserializeOwned> {
    #[serde(deserialize_with = "upcase_deserialize")]
    #[serde(flatten)]
    pub data: T,
}