use std::rc::Rc;

use anyhow::Error;
use itertools::Itertools;
use wasm_bindgen::{closure::Closure, prelude::wasm_bindgen};
use wasm_bindgen_futures::js_sys::Object;
use web_sys::{window, HtmlElement};
use yew::{
    function_component, html, use_effect_with, use_node_ref, use_state, use_state_eq, AttrValue,
    Callback, Html, Properties, UseStateHandle,
};

use crate::{FrameId, GlobalLayoutState, GlobalMemoCell, PanelDirection, SplitPanel};

#[derive(Properties, PartialEq, Clone)]
pub struct EditorViewProps {
    pub frame: FrameId,
    pub global_memo: GlobalMemoCell,
    pub global_layout: UseStateHandle<Rc<GlobalLayoutState>>,
}

#[derive(Properties, PartialEq, Clone)]
pub struct EditorViewDetailProps {
    pub frame: FrameId,
    pub global_memo: GlobalMemoCell,
    pub global_layout: UseStateHandle<Rc<GlobalLayoutState>>,
    pub editor_state: UseStateHandle<Rc<EditorViewState>>,
}

fn close_editor(frame: &FrameId, global_layout: &UseStateHandle<Rc<GlobalLayoutState>>) {
    let mut gl_new: GlobalLayoutState = global_layout.as_ref().clone();
    gl_new.frame_views.remove(frame);
    global_layout.set(gl_new.into());
}

#[derive(Clone, PartialEq)]
pub struct EditorViewState {
    error_msg: Option<AttrValue>,
    available_files: Vec<AttrValue>,
    open_file: AttrValue,
}

pub struct EditorKeepClosures {
    change_closure: Rc<Closure<dyn FnMut(ViewUpdate)>>,
}

fn fetch_initial_editor_state_or_fail() -> anyhow::Result<EditorViewState> {
    let win = window().ok_or_else(|| Error::msg("Can't get window"))?;
    let local = win
        .local_storage()
        .map_err(|_| Error::msg("Error retrieving localStorage"))?
        .ok_or_else(|| Error::msg("Local storage not available"))?;

    let n_keys = local
        .length()
        .map_err(|_| Error::msg("localStorage broken"))?;
    let mut available_files: Vec<AttrValue> = vec![];
    for i in 0..n_keys {
        if let Some(key) = local
            .key(i)
            .map_err(|_| Error::msg("localStorage broken"))?
        {
            match key.strip_prefix("scriptfile_") {
                None => {}
                Some(filename) => {
                    available_files.push(filename.to_owned().into());
                }
            }
        }
    }

    let init_str: AttrValue = "init.lua".into();
    if !available_files.contains(&init_str) {
        available_files.push(init_str);
        local
            .set(
                "scriptfile_init.lua",
                "-- Put any code to run on every client load here.\n",
            )
            .map_err(|_| Error::msg("localStorage broken"))?;
    }

    Ok(EditorViewState {
        error_msg: None,
        available_files,
        open_file: "init.lua".into(),
    })
}

fn fetch_initial_editor_state() -> Rc<EditorViewState> {
    match fetch_initial_editor_state_or_fail() {
        Ok(s) => s.into(),
        Err(e) => EditorViewState {
            error_msg: Some(format!("Can't load editor data: {}", e).into()),
            available_files: vec![],
            open_file: "init.lua".into(),
        }
        .into(),
    }
}

#[function_component(EditorNav)]
fn editor_nav(props: &EditorViewDetailProps) -> Html {
    let global_layout = props.global_layout.clone();
    let frame = props.frame.clone();
    html! {
        <div class="editornav">
          <nav class="navbar navbar-expand-lg bg-body-tertiary">
            <button class="btn" aria-label="New file" title="New file"><i class="bi bi-file-earmark-plus"></i></button>
            <div class="flex-fill"/>
            <button class="btn" onclick={move |_ev| close_editor(&frame, &global_layout)} aria-label="Close Editor" title="Close editor"><i class="bi bi-arrow-return-left"></i></button>
          </nav>
          <ul class="p-2 list-group">
        {props
         .editor_state
         .available_files
         .iter()
         .map(|f| {
             let mut classes = vec!["list-group-item"];
             let mut aria_current = None;
             if *f == props.editor_state.open_file {
                 aria_current = Some("true");
                 classes.push("active");
             }
             html! { <li aria-current={aria_current} class={classes.iter().join(" ")}>{f}</li>}
         })
         .collect::<Vec<Html>>()
        }
          </ul>
        </div>
    }
}

#[wasm_bindgen(getter_with_clone)]
struct EditorViewConfig {
    pub doc: String,
}

#[wasm_bindgen(getter_with_clone)]
struct EditorStateConfig {
    pub doc: String,
    pub extensions: Vec<CMExtension>,
}

#[wasm_bindgen(module = codemirror)]
extern "C" {
    #[derive(Clone)]
    type CMExtension;

    #[wasm_bindgen(constructor)]
    fn new(settings: EditorViewConfig) -> EditorView;

    #[wasm_bindgen(js_name = basicSetup, thread_local)]
    static BASIC_SETUP: CMExtension;
}

#[wasm_bindgen(module = "@codemirror/state")]
extern "C" {
    type EditorState;
    #[wasm_bindgen(extends = Object)]
    type CMDocument;

    #[wasm_bindgen(static_method_of = EditorState)]
    fn create(settings: EditorStateConfig) -> EditorState;

    #[wasm_bindgen(method, getter)]
    fn doc(st: &EditorState) -> CMDocument;
}

#[wasm_bindgen(module = "@codemirror/view")]
extern "C" {
    type EditorView;
    type ViewUpdate;

    #[wasm_bindgen(js_namespace = ["EditorView", "updateListener"], js_name = of)]
    fn editorview_updatelistener_of(cb: &Closure<dyn FnMut(ViewUpdate)>) -> CMExtension;

    #[wasm_bindgen(method, getter)]
    fn dom(upd: &EditorView) -> HtmlElement;

    #[wasm_bindgen(method, getter)]
    fn state(v: &EditorView) -> EditorState;

    #[wasm_bindgen(method, js_name = setState)]
    fn set_state(v: &EditorView, st: &EditorState);

    #[wasm_bindgen(method, getter, js_name = docChanged)]
    fn doc_changed(upd: &ViewUpdate) -> bool;

    #[wasm_bindgen(method, getter)]
    fn view(upd: &ViewUpdate) -> EditorView;
}

#[wasm_bindgen(module = "@codemirror/legacy-modes/mode/lua")]
extern "C" {
    #[wasm_bindgen(js_name = lua, thread_local)]
    static LUA: StreamLanguage;
}

#[wasm_bindgen(module = "@codemirror/language")]
extern "C" {
    #[derive(Clone)]
    type StreamLanguage;

    #[wasm_bindgen(js_namespace = StreamLanguage, js_name = define)]
    fn streamlanguage_define(input: StreamLanguage) -> CMExtension;
}

fn try_save_document(file: &str, contents: &str) -> anyhow::Result<()> {
    let win = window().ok_or_else(|| Error::msg("Can't get window"))?;
    let local = win
        .local_storage()
        .map_err(|_| Error::msg("Error retrieving localStorage"))?
        .ok_or_else(|| Error::msg("Local storage not available"))?;
    local
        .set(&format!("scriptfile_{}", file), contents)
        .map_err(|_| Error::msg("Error saving to localStorage"))
}

fn load_file_contents(file: &str) -> anyhow::Result<String> {
    let win = window().ok_or_else(|| Error::msg("Can't get window"))?;
    let local = win
        .local_storage()
        .map_err(|_| Error::msg("Error retrieving localStorage"))?
        .ok_or_else(|| Error::msg("Local storage not available"))?;
    Ok(local
        .get(&format!("scriptfile_{}", file))
        .map_err(|_| Error::msg("Error retrieving localStorage"))?
        .unwrap_or_else(|| "".to_owned()))
}

#[function_component(EditorArea)]
fn editor_area(props: &EditorViewDetailProps) -> Html {
    let node_ref = use_node_ref();
    let editor_state = props.editor_state.clone();
    let closures = use_state(|| EditorKeepClosures {
        change_closure: Closure::new(move |view_update: ViewUpdate| {
            if view_update.doc_changed() {
                if let Some(contents) = view_update.view().state().doc().to_string().as_string() {
                    match try_save_document(&editor_state.open_file, &contents) {
                        Ok(()) => {}
                        Err(e) => {
                            let mut new_state = (*editor_state.as_ref()).clone();
                            new_state.error_msg = Some(format!("Can't save: {}", e).into());
                            editor_state.set(new_state.into());
                        }
                    }
                }
            }
        })
        .into(),
    });
    let view = use_state(move || {
        EditorView::new(EditorViewConfig {
            doc: "Loading...".to_owned(),
        })
    });
    {
        let view = view.clone();
        use_effect_with(props.editor_state.open_file.clone(), move |open_file| {
            view.set_state(&EditorState::create(EditorStateConfig {
                doc: load_file_contents(open_file)
                    .unwrap_or_else(|e| format!("Error loading content: {}", e.to_string())),
                extensions: vec![
                    BASIC_SETUP.with(CMExtension::clone),
                    StreamLanguage::streamlanguage_define(LUA.with(StreamLanguage::clone)),
                    editorview_updatelistener_of(&closures.change_closure),
                ],
            }));
        });
    }
    use_effect_with(node_ref.clone(), move |node_ref| match node_ref.get() {
        None => {}
        Some(node) => {
            let _ = node.append_child(&view.dom());
        }
    });
    html! {
        <div class="editorarea" ref={node_ref.clone()}>
        </div>
    }
}

#[derive(Properties, PartialEq, Clone)]
pub struct ErrorBarProps {
    pub msg: AttrValue,
    pub dismiss: Callback<()>,
}

#[function_component(ErrorBar)]
fn error_bar(props: &ErrorBarProps) -> Html {
    let props = props.clone();
    html! {
        <div class="errorbar alert alert-danger alert-dismissible" role="alert">
            <span class="errorbar-msg">{props.msg.clone()}</span>
            <button class="btn-close" aria-label="Close" onclick={move |_ev| props.dismiss.emit(())}></button>
        </div>
    }
}

#[function_component(CodeEditorView)]
pub fn editor_view(props: &EditorViewProps) -> Html {
    let editor_state: UseStateHandle<Rc<EditorViewState>> =
        use_state_eq(fetch_initial_editor_state);

    let detail_props: EditorViewDetailProps = EditorViewDetailProps {
        frame: props.frame.clone(),
        global_memo: props.global_memo.clone(),
        global_layout: props.global_layout.clone(),
        editor_state: editor_state.clone(),
    };

    html! {
        <>
        {match editor_state.error_msg.as_ref() {
            None => { html! { <></> }}
            Some(msg) => {
                let editor_state = editor_state.clone();
                html! {
                    <ErrorBar msg={msg.clone()}
                    dismiss={move |()| editor_state.set(EditorViewState {
                        error_msg: None,
                        ..((*editor_state.as_ref()).clone())
                      }.into())
                    }/>
                }
            }
        }}
        <SplitPanel direction={PanelDirection::Horizontal}
        first={html!{<EditorNav ..detail_props.clone() />}}
        second={html!{<EditorArea ..detail_props.clone()/>}}
        />
        </>
    }
}