use std::env;
use std::error::Error;
use std::fs::OpenOptions;
use std::io::{Read, Write};
use std::{fs::File, path::PathBuf};

use serde::{Deserialize, Serialize};

use crate::Result;

pub fn get_world_location() -> Result<PathBuf> {
    match env::var("TOPAZ_WORLD") {
        Ok(x) => Ok(x.into()),
        Err(env::VarError::NotPresent) => Ok("/etc/topaz/world.toml".into()),
        Err(env::VarError::NotUnicode(_)) => Err("World location in env is invalid!".into()),
    }
}

#[derive(Debug, Serialize, Deserialize)]
pub struct Packages {
    pub official: Vec<String>,
    pub foreign: Vec<String>,
    pub ignore: Vec<String>,
}

#[derive(Debug, Serialize, Deserialize)]
pub struct World {
    packages: Packages,
}

impl Packages {
    pub fn new() -> Packages {
        Packages {
            official: Vec::new(),
            foreign: Vec::new(),
            ignore: Vec::new(),
        }
    }
}

impl Packages {
    pub fn exclude(&self, other: &Self) -> Self {
        let official = self
            .official
            .iter()
            .filter(|x| !other.official.contains(x))
            .cloned()
            .collect();
        let foreign = self
            .foreign
            .iter()
            .filter(|x| !other.foreign.contains(x))
            .cloned()
            .collect();

        Packages {
            official,
            foreign,
            ignore: Vec::new(),
        }
    }

    pub fn exclude_ignored(&mut self) {
        self.official.retain(|x| !self.ignore.contains(x));
        self.foreign.retain(|x| !self.ignore.contains(x));
    }
}

impl World {
    pub fn new_empty() -> World {
        World {
            packages: Packages::new(),
        }
    }

    pub fn get_packages(&self) -> &Packages {
        &self.packages
    }

    pub fn get_mut_packages(&mut self) -> &mut Packages {
        &mut self.packages
    }

    pub fn load_from(world_path: PathBuf) -> Result<World> {
        let mut file = File::open(world_path)?;
        let mut text = String::new();
        file.read_to_string(&mut text)?;

        let world: World = toml::from_str(&text)?;

        Ok(world)
    }

    pub fn save(&self, world_path: Option<PathBuf>, do_print: bool) -> Result<()> {
        let text = toml::to_string_pretty(self)?;

        if let Some(world_path) = world_path {
            let mut file = OpenOptions::new()
                .write(true)
                .create(true)
                .truncate(true)
                .open(world_path)?;

            file.write_all(text.as_bytes())?;
        }

        if do_print {
            println!("{}", text);
        }

        Ok(())
    }
}