use std::{
    cell::{LazyCell, RefCell},
    collections::HashMap,
    fmt::Write,
    rc::Rc,
    str::FromStr,
    time::Duration,
};

use mlua::{Error, Lua, Table, prelude::*};
use reqwest::{
    Method, Url,
    blocking::{Client, Response},
    header::HeaderMap,
};
use serde::{Deserialize, Serialize};


pub fn create_htmlua_stdlib(l: &Lua, stdout: &Rc<RefCell<String>>) -> mlua::Result<Table> {
    let t = l.create_table()?;

    // This cannot be the best way to do this

    let stdout_println = stdout.clone();
    t.set(
        "println",
        l.create_function(move |_, text: String| {
            let mut stdout_ref = stdout_println.borrow_mut();
            writeln!(stdout_ref, "{text}").map_err(mlua::Error::external)
        })?,
    )?;

    let stdout_print = stdout.clone();
    t.set(
        "print",
        l.create_function(move |_, text: String| {
            let mut stdout_ref = stdout_print.borrow_mut();
            write!(stdout_ref, "{text}").map_err(mlua::Error::external)
        })?,
    )?;

    t.set("http", create_http_lib(l)?)?;
    Ok(t)
}

#[allow(clippy::too_many_lines)]
fn create_http_lib(l: &Lua) -> mlua::Result<Table> {
    let t = l.create_table()?;
    let http_client: Rc<LazyCell<Client>> = Rc::new(LazyCell::new(|| {
        Client::builder()
            .timeout(std::time::Duration::from_secs(3))
            .user_agent("htmlua/0.1.0")
            .build()
            .unwrap()
    }));


    let client = http_client.clone();
    t.set(
        "get",
        l.create_function(move |_, url: String| {
            let res = client.get(url).send().map_err(|e| Error::RuntimeError(e.to_string()))?;
            let lua_res: LuaHttpResponse = TryFrom::try_from(res)?;
            Ok(lua_res)
        })?,
    )?;

    let client = http_client.clone();
    t.set(
        "post",
        l.create_function(move |_, url: String| {
            let res = client
                .post(url)
                .send()
                .map_err(|e| Error::RuntimeError(e.to_string()))?;
            let lua_res: LuaHttpResponse = TryFrom::try_from(res)?;
            Ok(lua_res)
        })?,
    )?;

    let client = http_client.clone();
    t.set(
        "get_with_data",
        l.create_function(move |_, (url, data): (String, HashMap<String, String>)| {
            let res = client
                .get(url)
                .query(&data)
                .send()
                .map_err(|e| Error::RuntimeError(e.to_string()))?;
            let lua_res: LuaHttpResponse = TryFrom::try_from(res)?;
            Ok(lua_res)
        })?,
    )?;

    let client = http_client.clone();
    t.set(
        "post_with_data_form",
        l.create_function(move |_, (url, data): (String, HashMap<String, String>)| {
            let res = client
                .post(url)
                .form(&data)
                .send()
                .map_err(|e| Error::RuntimeError(e.to_string()))?;
            let lua_res: LuaHttpResponse = TryFrom::try_from(res)?;
            Ok(lua_res)
        })?,
    )?;

    let client = http_client.clone();
    t.set(
        "post_with_data_json",
        l.create_function(move |_, (url, data): (String, HashMap<String, String>)| {
            let res = client
                .post(url)
                .json(&data)
                .send()
                .map_err(|e| Error::RuntimeError(e.to_string()))?;
            let lua_res: LuaHttpResponse = TryFrom::try_from(res)?;
            Ok(lua_res)
        })?,
    )?;

    let client = http_client.clone();
    t.set(
        "request",
        l.create_function(move |_, table: mlua::Table| {
            let mut request = client.request(
                Method::from_bytes(table.get::<String>("method")?.as_bytes())
                    .map_err(|e| Error::RuntimeError(e.to_string()))?,
                Url::from_str(table.get::<String>("url")?.as_str()).map_err(|e| Error::RuntimeError(e.to_string()))?,
            );

            if let Ok(header_tbl) = table.get::<mlua::Table>("headers") {
                request = header_tbl
                    .pairs::<String, String>()
                    .filter_map(std::result::Result::ok)
                    .fold(request, |req, (k, v)| req.header(k, v));
            }

            if let Ok(basic_auth) = table.get::<mlua::Table>("basic_auth") {
                request = request
                    .basic_auth(basic_auth.get::<String>("username")?, basic_auth.get::<String>("password").ok());
            }

            if let Ok(bearer_auth) = table.get::<mlua::Table>("bearer_auth") {
                request = request.bearer_auth(bearer_auth.get::<String>("token")?);
            }

            if let Ok(body) = table.get::<String>("body") {
                request = request.body(body);
            }

            if let Ok(json) = table.get::<String>("json") {
                request = request.json(&json);
            }

            if let Ok(timeout) = table.get::<u64>("timeout") {
                request = request.timeout(Duration::from_secs(timeout));
            }


            let res = request.send().map_err(|e| Error::RuntimeError(e.to_string()))?;
            let lua_res: LuaHttpResponse = TryFrom::try_from(res)?;
            Ok(lua_res)
        })?,
    )?;

    t.set(
        "decode_json",
        l.create_function(move |l, text: String| {
            let table: serde_json::Value =
                serde_json::from_str(&text).map_err(|e| Error::RuntimeError(e.to_string()))?;
            Ok(l.to_value(&table))
        })?,
    )?;

    Ok(t)
}


#[derive(Serialize, Deserialize)]
struct LuaHttpResponse {
    headers: HashMap<String, String>,
    body: String,
    status: u16,
}

impl TryFrom<Response> for LuaHttpResponse {
    fn try_from(value: Response) -> Result<Self, Self::Error> {
        Ok(LuaHttpResponse {
            headers: headermap_to_hashmap(value.headers()),
            status: value.status().as_u16(),
            body: value.text().map_err(|e| Error::RuntimeError(e.to_string()))?,
        })
    }

    type Error = Error;
}

fn headermap_to_hashmap(headers: &HeaderMap) -> HashMap<String, String> {
    let mut map = HashMap::new();

    for (name, value) in headers {
        if let Ok(value_str) = value.to_str() {
            map.insert(name.as_str().to_string(), value_str.to_string());
        }
    }

    map
}


impl IntoLua for LuaHttpResponse {
    fn into_lua(self, lua: &Lua) -> LuaResult<LuaValue> {
        let table = lua.create_table()?;

        table.set("status", self.status)?;
        table.set("body", self.body)?;

        let headers_table = lua.create_table()?;
        for (key, value) in self.headers {
            headers_table.set(key, value)?;
        }
        table.set("headers", headers_table)?;

        Ok(LuaValue::Table(table))
    }
}