use std::{
    collections::HashMap,
    sync::{Mutex, Weak},
};

use loro_internal::{
    container::registry::ContainerInstance, context::Context, ContainerType, LoroError, LoroValue,
    Prelim, PrelimValue,
};
use wasm_bindgen::prelude::*;

use crate::JsResult;

pub(crate) enum PrelimType {
    Text(PrelimText),
    Map(PrelimMap),
    List(PrelimList),
}

impl Prelim for PrelimType {
    fn convert_value(self) -> Result<(PrelimValue, Option<Self>), LoroError> {
        match self {
            PrelimType::Text(text) => {
                let (value, prelim) = text.convert_value()?;
                Ok((value, prelim.map(PrelimType::Text)))
            }
            PrelimType::Map(map) => {
                let (value, prelim) = map.convert_value()?;
                Ok((value, prelim.map(PrelimType::Map)))
            }
            PrelimType::List(list) => {
                let (value, prelim) = list.convert_value()?;
                Ok((value, prelim.map(PrelimType::List)))
            }
        }
    }

    fn integrate<C: Context>(
        self,
        ctx: &C,
        container: Weak<Mutex<ContainerInstance>>,
    ) -> Result<(), LoroError> {
        match self {
            PrelimType::Text(t) => t.integrate(ctx, container),
            PrelimType::Map(m) => m.integrate(ctx, container),
            PrelimType::List(l) => l.integrate(ctx, container),
        }
    }
}

#[wasm_bindgen]
pub struct PrelimText(String);

#[wasm_bindgen]
impl PrelimText {
    #[wasm_bindgen(constructor)]
    pub fn new(text: Option<String>) -> Self {
        Self(text.unwrap_or_default())
    }

    pub fn insert(&mut self, index: usize, text: &str) {
        self.0.insert_str(index, text);
    }

    pub fn delete(&mut self, index: usize, len: usize) {
        self.0.drain(index..index + len);
    }

    #[wasm_bindgen(js_name = "value", method, getter)]
    pub fn get_value(&self) -> String {
        self.0.clone()
    }
}

#[wasm_bindgen]
pub struct PrelimList(Vec<JsValue>);

#[wasm_bindgen]
impl PrelimList {
    #[wasm_bindgen(constructor)]
    pub fn new(list: Option<Vec<JsValue>>) -> Self {
        Self(list.unwrap_or_default())
    }

    pub fn insert(&mut self, index: usize, value: JsValue) {
        self.0.insert(index, value);
    }

    pub fn delete(&mut self, index: usize, len: usize) {
        self.0.drain(index..index + len);
    }

    #[wasm_bindgen(js_name = "value", method, getter)]
    pub fn get_value(&self) -> Vec<JsValue> {
        self.0.clone()
    }
}

#[wasm_bindgen]
pub struct PrelimMap(HashMap<String, JsValue>);

#[wasm_bindgen]
impl PrelimMap {
    #[wasm_bindgen(constructor)]
    pub fn new(obj: Option<js_sys::Object>) -> Self {
        let map = if let Some(object) = obj {
            let mut map = HashMap::new();
            let entries = js_sys::Object::entries(&object);
            for tuple in entries.iter() {
                let tuple = js_sys::Array::from(&tuple);
                let key = tuple.get(0).as_string().unwrap();
                let value = tuple.get(1);
                map.insert(key, value);
            }
            map
        } else {
            HashMap::new()
        };
        Self(map)
    }

    #[wasm_bindgen(js_name = set)]
    pub fn insert(&mut self, key: &str, value: JsValue) {
        self.0.insert(key.to_string(), value);
    }

    pub fn delete(&mut self, key: &str) {
        self.0.remove(key);
    }

    pub fn get(&self, key: &str) -> JsResult<JsValue> {
        if let Some(v) = self.0.get(key).cloned() {
            Ok(v)
        } else {
            Err(JsValue::from_str("Key not found"))
        }
    }

    // TODO: entries iterator
    #[wasm_bindgen(js_name = "value", method, getter)]
    pub fn get_value(&self) -> js_sys::Object {
        let object = js_sys::Object::new();
        for (key, value) in self.0.iter() {
            js_sys::Reflect::set(&object, &key.into(), value).unwrap();
        }
        object
    }
}

impl Prelim for PrelimText {
    fn convert_value(self) -> Result<(PrelimValue, Option<Self>), LoroError> {
        Ok((PrelimValue::Container(ContainerType::Text), Some(self)))
    }

    fn integrate<C: Context>(
        self,
        ctx: &C,
        container: Weak<Mutex<ContainerInstance>>,
    ) -> Result<(), LoroError> {
        let text = container.upgrade().unwrap();
        let mut text = text.try_lock().unwrap();
        let text = text.as_text_mut().unwrap();
        text.insert(ctx, 0, &self.0);
        Ok(())
    }
}

impl Prelim for PrelimList {
    fn convert_value(self) -> Result<(PrelimValue, Option<Self>), LoroError> {
        Ok((PrelimValue::Container(ContainerType::List), Some(self)))
    }

    fn integrate<C: Context>(
        self,
        ctx: &C,
        container: Weak<Mutex<ContainerInstance>>,
    ) -> Result<(), LoroError> {
        let list = container.upgrade().unwrap();
        let mut list = list.try_lock().unwrap();
        let list = list.as_list_mut().unwrap();
        let values: Vec<LoroValue> = self.0.into_iter().map(|v| v.into()).collect();
        list.insert_batch(ctx, 0, values);
        Ok(())
    }
}

impl Prelim for PrelimMap {
    fn convert_value(self) -> Result<(PrelimValue, Option<Self>), LoroError> {
        Ok((PrelimValue::Container(ContainerType::Map), Some(self)))
    }

    fn integrate<C: Context>(
        self,
        ctx: &C,
        container: Weak<Mutex<ContainerInstance>>,
    ) -> Result<(), LoroError> {
        let map = container.upgrade().unwrap();
        let mut map = map.try_lock().unwrap();
        let map = map.as_map_mut().unwrap();
        for (key, value) in self.0.into_iter() {
            let value: LoroValue = value.into();
            map.insert(ctx, key.into(), value)?;
        }
        Ok(())
    }
}

impl From<PrelimText> for PrelimType {
    fn from(p: PrelimText) -> Self {
        Self::Text(p)
    }
}

impl From<PrelimList> for PrelimType {
    fn from(p: PrelimList) -> Self {
        Self::List(p)
    }
}

impl From<PrelimMap> for PrelimType {
    fn from(p: PrelimMap) -> Self {
        Self::Map(p)
    }
}