use std::rc::Rc;
use std::cell::Cell;
use gloo_timers::callback::Interval;
use yew::prelude::*;
use yew_router::prelude::*;

use crate::api;
use crate::pages::Route;
use crate::types::FullArtistDetail;

#[derive(Properties, PartialEq)]
pub struct Props {
    pub id: String,
}

#[function_component(ArtistPage)]
pub fn artist_page(props: &Props) -> Html {
    let detail = use_state(|| None::<FullArtistDetail>);
    let error = use_state(|| None::<String>);
    let message = use_state(|| None::<String>);
    let id = props.id.clone();

    // Flag to prevent the background enrichment from overwriting a user-triggered refresh
    let user_acted: Rc<Cell<bool>> = use_memo((), |_| Cell::new(false));

    // Full fetch (with track counts) — used for refresh after actions
    let fetch = {
        let detail = detail.clone();
        let error = error.clone();
        let user_acted = user_acted.clone();
        Callback::from(move |id: String| {
            user_acted.set(true);
            let detail = detail.clone();
            let error = error.clone();
            wasm_bindgen_futures::spawn_local(async move {
                match api::get_artist_full(&id).await {
                    Ok(d) => detail.set(Some(d)),
                    Err(e) => error.set(Some(e.0)),
                }
            });
        })
    };

    // Two-phase load: quick first (release groups only), then enriched (with track counts)
    {
        let detail = detail.clone();
        let error = error.clone();
        let id = id.clone();
        let user_acted = user_acted.clone();
        use_effect_with(id.clone(), move |_| {
            user_acted.set(false);
            wasm_bindgen_futures::spawn_local(async move {
                // Phase 1: quick load (instant for browsing artists)
                match api::get_artist_full_quick(&id).await {
                    Ok(d) => {
                        let needs_enrich = !d.enriched;
                        detail.set(Some(d));

                        // Phase 2: if not enriched, fetch full data in background
                        if needs_enrich && !user_acted.get() {
                            match api::get_artist_full(&id).await {
                                Ok(full) => {
                                    // Only apply if user hasn't triggered a refresh
                                    if !user_acted.get() {
                                        detail.set(Some(full));
                                    }
                                }
                                Err(_) => {} // quick data is still showing, don't overwrite with error
                            }
                        }
                    }
                    Err(e) => error.set(Some(e.0)),
                }
            });
        });
    }

    // Auto-refresh when background tasks complete (downloads, organize, etc.)
    {
        let fetch = fetch.clone();
        let id = id.clone();
        let had_tasks: Rc<Cell<bool>> = use_memo((), |_| Cell::new(false));
        use_effect_with((), move |_| {
            let interval = Interval::new(3_000, move || {
                let fetch = fetch.clone();
                let id = id.clone();
                let had_tasks = had_tasks.clone();
                wasm_bindgen_futures::spawn_local(async move {
                    if let Ok(status) = api::get_status().await {
                        let has_running = status.tasks.iter().any(|t| t.status == "Running");
                        if had_tasks.get() && !has_running {
                            // Tasks just finished — refresh artist data
                            fetch.emit(id);
                        }
                        had_tasks.set(has_running);
                    }
                });
            });
            move || drop(interval)
        });
    }

    if let Some(ref err) = *error {
        return html! { <div class="error">{ format!("Error: {err}") }</div> };
    }

    let Some(ref d) = *detail else {
        return html! { <p class="loading">{ "Loading discography from MusicBrainz..." }</p> };
    };

    let watch_all_btn = {
        let artist_status = d.artist_status.clone();
        let show = artist_status != "owned";
        if show {
            let artist_name = d.artist.name.clone();
            let artist_mbid = d.artist.musicbrainz_id.clone();
            let message = message.clone();
            let error = error.clone();
            let fetch = fetch.clone();
            let artist_id = id.clone();
            html! {
                <button class="btn btn-sm btn-success"
                    onclick={Callback::from(move |_: MouseEvent| {
                        let artist_name = artist_name.clone();
                        let artist_mbid = artist_mbid.clone();
                        let message = message.clone();
                        let error = error.clone();
                        let fetch = fetch.clone();
                        let artist_id = artist_id.clone();
                        wasm_bindgen_futures::spawn_local(async move {
                            match api::add_artist(&artist_name, artist_mbid.as_deref()).await {
                                Ok(s) => {
                                    message.set(Some(format!(
                                        "Watching {}: added {} tracks ({} already owned)",
                                        artist_name, s.tracks_added, s.tracks_already_owned
                                    )));
                                    fetch.emit(artist_id);
                                }
                                Err(e) => error.set(Some(e.0)),
                            }
                        });
                    })}>
                    { "Watch All" }
                </button>
            }
        } else {
            html! {}
        }
    };

    html! {
        <div>
            <div class="page-header">
                <div class="flex items-center justify-between">
                    <h2>{ &d.artist.name }</h2>
                    { watch_all_btn }
                </div>
                if d.enriched {
                    <p class="text-sm">
                        <span style="color: var(--accent);">
                            { format!("{}/{} watched", d.total_watched_tracks, d.total_available_tracks) }
                        </span>
                        { " · " }
                        <span style="color: var(--success);">
                            { format!("{} owned", d.total_owned_tracks) }
                        </span>
                    </p>
                } else {
                    <p class="text-sm text-muted loading">{ "Loading track counts..." }</p>
                }
            </div>

            if let Some(ref msg) = *message {
                <div class="card" style="border-color: var(--success);">
                    <p>{ msg }</p>
                </div>
            }

            if d.albums.is_empty() {
                <p class="text-muted">{ "No releases found on MusicBrainz." }</p>
            }

            // Group albums by type
            { for ["Album", "EP", "Single"].iter().map(|release_type| {
                let type_albums: Vec<_> = d.albums.iter()
                    .filter(|a| a.release_type.as_deref().unwrap_or("Album") == *release_type)
                    .collect();
                if type_albums.is_empty() {
                    return html! {};
                }
                html! {
                    <div class="mb-2">
                        <h3 class="mb-1">{ format!("{}s ({})", release_type, type_albums.len()) }</h3>
                        <table>
                            <thead>
                                <tr>
                                    <th>{ "Title" }</th>
                                    <th>{ "Date" }</th>
                                    <th>{ "Owned" }</th>
                                    <th>{ "Watched" }</th>
                                    <th></th>
                                </tr>
                            </thead>
                            <tbody>
                                { for type_albums.iter().map(|album| {
                            let is_unwatched = album.status == "unwatched";
                            let row_style = if is_unwatched { "opacity: 0.6;" } else { "" };

                            let album_link = html! {
                                <Link<Route> to={Route::Album { mbid: album.mbid.clone() }}>
                                    { &album.title }
                                </Link<Route>>
                            };

                            let tc = album.track_count;

                            // Watch button for unwatched albums
                            let watch_btn = if is_unwatched {
                                let artist_name = d.artist.name.clone();
                                let album_title = album.title.clone();
                                let album_mbid = album.mbid.clone();
                                let message = message.clone();
                                let error = error.clone();
                                let fetch = fetch.clone();
                                let artist_id = id.clone();
                                html! {
                                    <button class="btn btn-sm btn-primary"
                                        onclick={Callback::from(move |_: MouseEvent| {
                                            let artist_name = artist_name.clone();
                                            let album_title = album_title.clone();
                                            let album_mbid = album_mbid.clone();
                                            let message = message.clone();
                                            let error = error.clone();
                                            let fetch = fetch.clone();
                                            let artist_id = artist_id.clone();
                                            wasm_bindgen_futures::spawn_local(async move {
                                                match api::add_album(&artist_name, &album_title, Some(&album_mbid)).await {
                                                    Ok(s) => {
                                                        message.set(Some(format!(
                                                            "Added {} tracks from '{}'",
                                                            s.tracks_added, album_title
                                                        )));
                                                        fetch.emit(artist_id);
                                                    }
                                                    Err(e) => error.set(Some(e.0)),
                                                }
                                            });
                                        })}>
                                        { "Watch" }
                                    </button>
                                }
                            } else {
                                html! {}
                            };

                            html! {
                                <tr style={row_style}>
                                    <td>{ album_link }</td>
                                    <td class="text-muted">{ album.date.as_deref().unwrap_or("") }</td>
                                    <td>
                                        if tc > 0 {
                                            <span class="text-sm" style={
                                                if album.owned_tracks >= tc { "color: var(--success);" }
                                                else if album.owned_tracks > 0 { "color: var(--warning);" }
                                                else { "color: var(--text-muted);" }
                                            }>
                                                { format!("{}/{}", album.owned_tracks, tc) }
                                            </span>
                                        }
                                    </td>
                                    <td>
                                        if tc > 0 {
                                            <span class="text-sm" style={
                                                if album.watched_tracks >= tc { "color: var(--accent);" }
                                                else if album.watched_tracks > 0 { "color: var(--accent);" }
                                                else { "color: var(--text-muted);" }
                                            }>
                                                { format!("{}/{}", album.watched_tracks, tc) }
                                            </span>
                                        }
                                    </td>
                                    <td>{ watch_btn }</td>
                                </tr>
                            }
                        })}
                            </tbody>
                        </table>
                    </div>
                }
            })}
        </div>
    }
}