use std::fs::{File, OpenOptions};
use std::io::{Read, Write, Error};
use std::path::{Path, PathBuf};
use rocket::request::FromForm;
use crate::store::model::Model;
use std::collections::HashMap;

pub mod model;
pub mod form;

/// Store instance
#[derive(Debug)]
pub struct Store {
    path : PathBuf,
    pub model: Model,
    pub items : HashMap<usize, serde_json::Value>,
    pub index : Indexes,
}

/// Indexes loaded from the indexes file
#[derive(Serialize,Deserialize,Debug,Default)]
pub struct Indexes {
    pub free_enums : HashMap<String, Vec<String>>,
    pub free_tags : HashMap<String, Vec<String>>,
}

/// Struct loaded from the repositroy config file
#[derive(Serialize,Deserialize,Debug)]
struct RepositoryConfig {
    pub model : Model,
}

const REPO_CONFIG_FILE : &'static str = "repository.yaml";
const REPO_DATA_FILE : &'static str = "data.json";
const REPO_INDEX_FILE : &'static str = "index.json";

impl Store {
    pub fn new(path: impl AsRef<Path>) -> Self {
        let file = load_file(path.as_ref().join(REPO_CONFIG_FILE));

        let repository_config : RepositoryConfig = serde_yaml::from_str(&file)
            .expect("Error parsing repository config file.");

        let items = load_file_or(path.as_ref().join(REPO_DATA_FILE), "{}");
        let indexes = load_file_or(path.as_ref().join(REPO_INDEX_FILE), "{}");

        Store {
            path: path.as_ref().into(),
            model: repository_config.model,
            items: serde_json::from_str(&items).expect("Error parsing data file."),
            index: serde_json::from_str(&indexes).unwrap_or_default(),
        }
    }

    pub fn persist(&self) {
        let mut file = OpenOptions::new()
            .write(true)
            .create(true)
            .truncate(true)
            .open(self.path.join(REPO_DATA_FILE))
            .expect("Error opening data file for writing.");

        let serialized = serde_json::to_string(&self.items).expect("Error serialize.");
        file.write(serialized.as_bytes()).expect("Error write data file");
    }
}

fn load_file(path: impl AsRef<Path>) -> String {
    let mut file= File::open(&path).expect(&format!("Error opening file {}", path.as_ref().display()));

    let mut buf = String::new();
    file.read_to_string(&mut buf).expect(&format!("Error reading file {}", path.as_ref().display()));
    buf
}

fn load_file_or(file : impl AsRef<Path>, def : impl Into<String>) -> String {
    let mut file = match File::open(file) {
        Ok(file) => file,
        Err(_) => return def.into()
    };

    let mut buf = String::new();
    if file.read_to_string(&mut buf).is_err() {
        return def.into();
    }

    buf
}