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

#[test]
fn add_searcher_works() {
    // These should end up in the same hash slot.
    let name_owned = Cow::from("lume".to_string());
    let name_ref = Cow::from("lume");

    // `lume_ref` should overwrite `lume_owned`.
    let lume_owned = Cow::from(read_lume_to_string());
    let lume_ref = Cow::from(read_lume_to_str());

    let mut map = HashMap::new();
    map.insert(name_owned, lume_owned);
    map.insert(name_ref, lume_ref);

    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 ref", hello);

    // Repeat the experiment, but with an additional overwrite.
    let name_owned = Cow::from("lume".to_string());
    let name_ref = Cow::from("lume");
    let lume_owned = Cow::from(read_lume_to_string());
    let lume_ref = Cow::from(read_lume_to_str());

    let mut map = HashMap::new();
    map.insert(name_owned, lume_owned);
    map.insert(name_ref, lume_ref);

    let name_owned = Cow::from("lume".to_string());
    let lume_owned = Cow::from(read_lume_to_string());
    map.insert(name_owned, lume_owned);

    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 owned", hello);
}

#[test]
fn add_path_searcher_works() {
    let name = Cow::from("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 = Cow::from("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.as_ref(), 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.as_ref(), 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);
}

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

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

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

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

    let instrument_loader: Box<
        dyn for<'ctx> Fn(Context<'ctx>, Table<'ctx>, &str) -> rlua::Result<Function<'ctx>> + Send,
    > = Box::new(|lua_ctx, env, name| {
        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(lua_ctx
            .load("return instrument")
            .set_name(name)?
            .set_environment(env)?
            .into_function()?)
    });

    modules.insert(Cow::from("instrument".to_string()), 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()));
    }
}

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

    let mut modules: HashMap<
        Cow<'static, str>,
        for<'ctx> fn(Context<'ctx>, Table<'ctx>, &str) -> rlua::Result<Function<'ctx>>,
    > = HashMap::new();

    modules.insert(Cow::from("cartridge".to_string()), cartridge_loader);

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

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

            Ok(lua_ctx
                .load(
                    r#"local cartridge = require("cartridge")
                       local smash = cartridge.pick()
                       return smash:play()"#,
                )
                .eval()?)
        })
        .unwrap();

    assert_eq!(title, "Super Smash Brothers 64");
}

struct Cartridge {
    title: String,
}

impl Cartridge {
    pub fn pick() -> Self {
        let title = "Super Smash Brothers 64".to_string();
        Self { title }
    }

    pub fn play(&self) -> String {
        self.title.clone()
    }
}

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

fn cartridge_loader<'ctx>(
    lua_ctx: Context<'ctx>,
    env: Table<'ctx>,
    name: &str,
) -> rlua::Result<Function<'ctx>> {
    let globals = lua_ctx.globals();
    let pick = lua_ctx.create_function(|_, ()| Ok(Cartridge::pick()))?;
    let tbl = lua_ctx.create_table()?;
    tbl.set("pick", pick)?;
    globals.set("cartridge", tbl)?;
    Ok(lua_ctx
        .load("return cartridge")
        .set_name(name)?
        .set_environment(env)?
        .into_function()?)
}