use std::collections::HashMap;
use std::fs::File;
use std::io::BufReader;
use std::io::BufWriter;
use crate::{err, DB, dev_urandom, KeyStore};
use crate::ApiKey;

impl KeyStore for DB {
    fn new_entry(filename: String, name: String) -> err::Result<String> {
        //! Create a new API key entry in the data-store given by <filename>
        //! Key value is generated via /dev/urandom on unix systems
        let file = File::open(filename.as_str())?;
        let reader = BufReader::new(file);

        let mut data: DB = serde_json::from_reader(reader)?;
        // Generate some new key data
        let key = dev_urandom().unwrap(); // create a new key
        let entry = ApiKey { key: key.clone(), name };

        // Finally write back the data to the structure and disk
        data.keys.push(entry);
        let file = File::open(filename.as_str())?;
        let writer = BufWriter::new(file);
        serde_json::to_writer(writer, &data)?;

        Ok(key)
    }

    fn remove_entry(filename: String, name: String) -> err::Result<bool> {
        //! Removes the API key entry based on the given name 
        let file = File::open(filename.as_str())?;
        let reader = BufReader::new(file);

        let mut data: DB  = serde_json::from_reader(reader)?;
        let idx = data.keys.iter().position(|item| item.name == name);
        if let Some(idx) = idx {
            data.keys.remove(idx);
            Ok(true)
        } else {
            Ok(false)
        }
    }

    fn get_entry(filename: String, name: String) -> err::Result<Option<String>> {
        //! Get the API key based on name
        let file = File::open(filename.as_str())?;
        let reader = BufReader::new(file);

        let data: DB = serde_json::from_reader(reader)?;
        // WARNING: extreme autism
        match data.keys.iter().find(|item| item.name == name) {
            Some(item) => Ok(Some(item.key.clone())),
            None => Ok(None)
        }
    }

    fn new_store(filename: String) -> err::Result<()> {
        //!  Generate a new empty data store with the given filename
        //! NOTE: The filename must include the extension(programmatically)
        let file = File::create(filename)?;
        let empty = DB { keys: vec![] , videos: HashMap::new() };
        let writer = BufWriter::new(file);
        serde_json::to_writer(writer, &empty)?;
        Ok(())
    }
}