use std::fs::File;
use std::io::Write;

use crate::domain;
use crate::repo::{Error, InsertTaskData, Repository};

use serde::{Deserialize, Serialize};
use xdg::BaseDirectories;

#[derive(Deserialize, Serialize, Clone)]
pub struct Task {
    name: String,
    link: Option<String>,
    // created_at
}

impl From<Task> for domain::Task {
    fn from(repo: Task) -> Self {
        domain::Task {
            name: repo.name,
            link: repo.link,
        }
    }
}

const DATA_FILE: &str = "data.json";

pub struct FsRepo {
    xdg_dirs: BaseDirectories,
}

impl FsRepo {
    pub fn new(xdg_dirs: BaseDirectories) -> Self {
        Self { xdg_dirs }
    }
}

impl Repository for FsRepo {
    fn get_tasks(&self) -> Result<Vec<domain::Task>, Error> {
        self.get_tasks_impl()
            .map(|tasks| tasks.into_iter().map(Task::into).collect())
    }

    fn insert_task(&self, insert_data: InsertTaskData) -> Result<domain::Task, Error> {
        let new_task = Task {
            name: insert_data.name,
            link: insert_data.link,
        };

        let mut tasks = self.get_tasks_impl()?;
        tasks.push(new_task.clone());

        let file_path = self
            .xdg_dirs
            .place_data_file(DATA_FILE)
            .map_err(|_| Error::InsertData)?;
        let mut file = File::create(&file_path).map_err(|_| Error::InsertData)?;
        let new_data = serde_json::to_vec(&tasks).map_err(|_| Error::InvalidData)?;
        file.write_all(&new_data).map_err(|_| Error::InsertData);

        Ok(new_task.into())
    }
}

impl FsRepo {
    fn get_tasks_impl(&self) -> Result<Vec<Task>, Error> {
        let file_path = self.xdg_dirs.get_data_file(DATA_FILE);
        File::open(&file_path)
            .map_err(|_| Error::NotFound)
            .and_then(|file| serde_json::from_reader(file).map_err(|_| Error::InvalidData))
    }
}