//! The page behind a guest link: `/#l=<token>`.

use api::{GuestAuth, GuestKey, GuestUnlock, GuestView};
use leptos::prelude::*;
use leptos::task::spawn_local;

use crate::{ThemeToggle, http, map};

#[derive(Clone, PartialEq)]
enum State {
    Loading,
    Locked,
    Open(String),
    Gone,
    Failed(String),
}

fn storage() -> Option<web_sys::Storage> {
    window().session_storage().ok().flatten()
}

#[component]
pub fn GuestPage(token: String) -> impl IntoView {
    let storage_key = format!("link {token}");
    let key = RwSignal::new(storage().and_then(|s| s.get_item(&storage_key).ok().flatten()));
    let token = StoredValue::new(token);
    let auth = move || GuestAuth {
        token: token.get_value(),
        key: key.get_untracked(),
    };
    let state = RwSignal::new(State::Loading);
    let check = move || {
        spawn_local(async move {
            state.set(match http::post::<GuestView>("/api/guest", &auth()).await {
                Ok(v) => State::Open(v.person.username),
                Err(e) if e.status == 401 => State::Locked,
                Err(e) if e.status == 404 => State::Gone,
                Err(e) => State::Failed(e.to_string()),
            })
        })
    };
    check();

    let password = RwSignal::new(String::new());
    let error = RwSignal::new(None::<String>);
    let unlock = move |ev: leptos::ev::SubmitEvent| {
        ev.prevent_default();
        let body = GuestUnlock {
            token: token.get_value(),
            password: password.get_untracked(),
        };
        let storage_key = storage_key.clone();
        spawn_local(async move {
            match http::post::<GuestKey>("/api/guest/unlock", &body).await {
                Ok(k) => {
                    if let Some(s) = storage() {
                        let _ = s.set_item(&storage_key, &k.key);
                    }
                    key.set(Some(k.key));
                    error.set(None);
                    check();
                }
                Err(e) => error.set(Some(match e.status {
                    401 => "Wrong password.".into(),
                    429 => "Too many failed attempts. Try again in 15 minutes.".into(),
                    _ => e.to_string(),
                })),
            }
        });
    };

    let title = move || match state.get() {
        State::Open(name) => format!("Location of {name}"),
        _ => "Shared location".into(),
    };
    view! {
        <header>
            <img class="brand" src="/icon.svg" alt="opentracker" width="28" height="28" />
            <span class="guest-title">{title}</span>
            <ThemeToggle />
        </header>
        {move || match state.get() {
            State::Loading => ().into_any(),
            State::Locked => {
                view! {
                    <form class="login" on:submit=unlock.clone()>
                        <p>"This shared location is protected with a password."</p>
                        <label>
                            "Password"
                            <input type="password" autocomplete="current-password" required bind:value=password />
                        </label>
                        <button class="primary">"Show location"</button>
                        <p class="error">{move || error.get()}</p>
                    </form>
                }
                    .into_any()
            }
            State::Open(_) => view! { <main><map::MapPage source=map::Source::Guest(auth()) /></main> }.into_any(),
            State::Gone => {
                view! { <p class="login">"This link is no longer valid. It may have expired or been deleted."</p> }
                    .into_any()
            }
            State::Failed(msg) => view! { <p class="login error">{msg}</p> }.into_any(),
        }}
    }
}