use rlua::{Context, Lua, Table, UserData, UserDataMethods, Value};
use rlua_searcher::{AddSearcher, Result};
use std::collections::HashMap;
use std::fs::File;
use std::io::Write;
use std::path::PathBuf;

#[test]
fn add_searcher_works() {
    let lume = read_lume_to_string();
    let name = "lume".to_string();
    let mut map = HashMap::new();
    map.insert(name, lume);

    let lua = Lua::new();

    let hello = lua
        .context::<_, Result<String>>(|lua_ctx| {
            lua_ctx.add_searcher(map)?;
            Ok(lua_ctx.load(r#"return require("lume")"#).eval()?)
        })
        .unwrap();

    assert_eq!("hello lume", hello);
}

#[test]
fn add_static_searcher_works() {
    let lume = read_lume_to_str();
    let name = "lume";
    let mut map = HashMap::new();
    map.insert(name, lume);

    let lua = Lua::new();

    let hello = lua
        .context::<_, Result<String>>(|lua_ctx| {
            lua_ctx.add_static_searcher(map)?;
            Ok(lua_ctx.load(r#"return require("lume")"#).eval()?)
        })
        .unwrap();

    assert_eq!("hello lume", hello);
}

#[test]
fn add_path_searcher_works() {
    let name = "lume".to_string();
    let path = PathBuf::new()
        .join(std::env::var("CARGO_MANIFEST_DIR").unwrap())
        .join("tests")
        .join("data")
        .join("lume.lua");
    let mut map = HashMap::new();
    map.insert(name, path);

    let lua = Lua::new();

    let hello = lua
        .context::<_, Result<String>>(|lua_ctx| {
            lua_ctx.add_path_searcher(map)?;
            Ok(lua_ctx.load(r#"return require("lume")"#).eval()?)
        })
        .unwrap();

    assert_eq!("hello lume", hello);
}

#[test]
fn module_reloading_works() {
    let name = "lume".to_string();
    let path = PathBuf::new()
        .join(std::env::var("CARGO_MANIFEST_DIR").unwrap())
        .join("tests")
        .join("data")
        .join("lume.lua");
    let mut map = HashMap::new();
    map.insert(name.clone(), path.clone());

    let lua = Lua::new();

    // Add searcher for lume module on disk, and read from it.
    let hello = lua
        .context::<_, Result<String>>(|lua_ctx| {
            lua_ctx.add_path_searcher(map)?;
            Ok(lua_ctx.load(r#"return require("lume")"#).eval()?)
        })
        .unwrap();

    assert_eq!("hello lume", hello);

    // Twice.
    let hello = lua
        .context::<_, Result<String>>(|lua_ctx| {
            Ok(lua_ctx.load(r#"return require("lume")"#).eval()?)
        })
        .unwrap();

    assert_eq!("hello lume", hello);

    // Modify lume module on disk.
    let mut out = File::create(path.clone()).expect("Could not create Lume module on disk");
    write!(out, "{}\n", r#"return "hello again lume""#)
        .expect("Could not modify Lume module on disk");

    // Thrice. Should still be unchanged due to caching.
    let hello = lua
        .context::<_, Result<String>>(|lua_ctx| {
            Ok(lua_ctx.load(r#"return require("lume")"#).eval()?)
        })
        .unwrap();

    assert_eq!("hello lume", hello);

    // Remove lume module from Lua’s `package.loaded` cache to facilitate reload.
    lua.context::<_, rlua::Result<()>>(|lua_ctx| {
        let globals = lua_ctx.globals();
        let loaded: Table = globals.get::<_, Table>("package")?.get("loaded")?;
        loaded.set(name.clone(), Value::Nil)
    })
    .unwrap();

    // Re-read from lume module on disk.
    let hello = lua
        .context::<_, Result<String>>(|lua_ctx| {
            Ok(lua_ctx.load(r#"return require("lume")"#).eval()?)
        })
        .unwrap();

    assert_eq!("hello again lume", hello);

    // Twice.
    let hello = lua
        .context::<_, Result<String>>(|lua_ctx| {
            Ok(lua_ctx.load(r#"return require("lume")"#).eval()?)
        })
        .unwrap();

    assert_eq!("hello again lume", hello);

    // Revert changes to lume module on disk.
    let mut out = File::create(path).expect("Could not create Lume module on disk");
    write!(out, "{}\n", r#"return "hello lume""#).expect("Could not modify Lume module on disk");

    // Clear cache again.
    lua.context::<_, rlua::Result<()>>(|lua_ctx| {
        let globals = lua_ctx.globals();
        let loaded: Table = globals.get::<_, Table>("package")?.get("loaded")?;
        loaded.set(name, Value::Nil)
    })
    .unwrap();

    // Ensure changes have been successfully reverted.
    let hello = lua
        .context::<_, Result<String>>(|lua_ctx| {
            Ok(lua_ctx.load(r#"return require("lume")"#).eval()?)
        })
        .unwrap();

    assert_eq!("hello lume", hello);
}

#[test]
fn add_closure_searcher_works() {
    let lua = Lua::new();

    let mut modules: HashMap<
        &'static str,
        Box<dyn Fn(Context) -> rlua::Result<&'static str> + Send>,
    > = HashMap::new();

    let instrument_loader = Box::new(|lua_ctx: Context| {
        let globals = lua_ctx.globals();
        let new = lua_ctx.create_function(|_, (name, sound): (String, String)| {
            Ok(Instrument::new(name, sound))
        })?;
        let tbl = lua_ctx.create_table()?;
        tbl.set("new", new)?;
        globals.set("instrument", tbl)?;
        Ok("return instrument")
    });

    modules.insert("instrument", instrument_loader);

    let sound = lua
        .context::<_, Result<String>>(|lua_ctx| {
            lua_ctx.add_closure_searcher(modules)?;

            // Ensure global variable `instrument` is unset.
            let nil: String = lua_ctx.load("return type(instrument)").eval()?;
            assert_eq!(nil, "nil");

            Ok(lua_ctx
                .load(
                    r#"local instrument = require("instrument")
                       local ukulele = instrument.new("ukulele", "twang")
                       return ukulele:play()"#,
                )
                .eval()?)
        })
        .unwrap();

    assert_eq!(sound, "The ukulele goes twang");
}

struct Instrument {
    name: String,
    sound: String,
}

impl Instrument {
    pub fn new(name: String, sound: String) -> Self {
        Self { name, sound }
    }

    pub fn play(&self) -> String {
        format!("The {} goes {}", self.name, self.sound)
    }
}

impl UserData for Instrument {
    fn add_methods<'lua, M>(methods: &mut M)
    where
        M: UserDataMethods<'lua, Self>,
    {
        methods.add_method("play", |_, instrument, ()| Ok(instrument.play()));
    }
}

fn read_lume_to_string() -> String {
    r#"return "hello lume""#.to_string()
}

fn read_lume_to_str() -> &'static str {
    r#"return "hello lume""#
}