use yew::prelude::*;
use yew_router::prelude::*;
use gloo_storage::{LocalStorage, Storage};
use crate::components::{Login, Calendar};
use crate::services::{CalendarService, CalendarEvent};
use std::collections::HashMap;
use chrono::{Local, NaiveDate, Datelike};

#[derive(Clone, Routable, PartialEq)]
enum Route {
    #[at("/")]
    Home,
    #[at("/login")]
    Login,
    #[at("/calendar")]
    Calendar,
}

#[function_component]
pub fn App() -> Html {
    let auth_token = use_state(|| -> Option<String> {
        LocalStorage::get("auth_token").ok()
    });

    let on_login = {
        let auth_token = auth_token.clone();
        Callback::from(move |token: String| {
            auth_token.set(Some(token));
        })
    };

    let on_logout = {
        let auth_token = auth_token.clone();
        Callback::from(move |_| {
            let _ = LocalStorage::delete("auth_token");
            auth_token.set(None);
        })
    };

    html! {
        <BrowserRouter>
            <div class="app">
                {
                    if auth_token.is_some() {
                        html! {
                            <>
                                <aside class="app-sidebar">
                                    <div class="sidebar-header">
                                        <h1>{"Calendar App"}</h1>
                                    </div>
                                    <nav class="sidebar-nav">
                                        <Link<Route> to={Route::Calendar} classes="nav-link">{"Calendar"}</Link<Route>>
                                        <button onclick={on_logout} class="logout-button">{"Logout"}</button>
                                    </nav>
                                </aside>
                                <main class="app-main">
                                    <Switch<Route> render={move |route| {
                                        let auth_token = (*auth_token).clone();
                                        let on_login = on_login.clone();
                                        
                                        match route {
                                            Route::Home => {
                                                if auth_token.is_some() {
                                                    html! { <Redirect<Route> to={Route::Calendar}/> }
                                                } else {
                                                    html! { <Redirect<Route> to={Route::Login}/> }
                                                }
                                            }
                                            Route::Login => {
                                                if auth_token.is_some() {
                                                    html! { <Redirect<Route> to={Route::Calendar}/> }
                                                } else {
                                                    html! { <Login {on_login} /> }
                                                }
                                            }
                                            Route::Calendar => {
                                                if auth_token.is_some() {
                                                    html! { <CalendarView /> }
                                                } else {
                                                    html! { <Redirect<Route> to={Route::Login}/> }
                                                }
                                            }
                                        }
                                    }} />
                                </main>
                            </>
                        }
                    } else {
                        html! {
                            <div class="login-layout">
                                <Switch<Route> render={move |route| {
                                    let auth_token = (*auth_token).clone();
                                    let on_login = on_login.clone();
                                    
                                    match route {
                                        Route::Home => {
                                            if auth_token.is_some() {
                                                html! { <Redirect<Route> to={Route::Calendar}/> }
                                            } else {
                                                html! { <Redirect<Route> to={Route::Login}/> }
                                            }
                                        }
                                        Route::Login => {
                                            if auth_token.is_some() {
                                                html! { <Redirect<Route> to={Route::Calendar}/> }
                                            } else {
                                                html! { <Login {on_login} /> }
                                            }
                                        }
                                        Route::Calendar => {
                                            if auth_token.is_some() {
                                                html! { <CalendarView /> }
                                            } else {
                                                html! { <Redirect<Route> to={Route::Login}/> }
                                            }
                                        }
                                    }
                                }} />
                            </div>
                        }
                    }
                }
            </div>
        </BrowserRouter>
    }
}

#[function_component]
fn CalendarView() -> Html {
    let events = use_state(|| HashMap::<NaiveDate, Vec<CalendarEvent>>::new());
    let loading = use_state(|| true);
    let error = use_state(|| None::<String>);
    let refreshing_event = use_state(|| None::<String>);
    
    // Get current auth token
    let auth_token: Option<String> = LocalStorage::get("auth_token").ok();
    
    let today = Local::now().date_naive();
    let current_year = today.year();
    let current_month = today.month();
    
    // Event refresh callback
    let on_event_click = {
        let events = events.clone();
        let refreshing_event = refreshing_event.clone();
        let auth_token = auth_token.clone();
        
        Callback::from(move |event: CalendarEvent| {
            if let Some(token) = auth_token.clone() {
                let events = events.clone();
                let refreshing_event = refreshing_event.clone();
                let uid = event.uid.clone();
                
                refreshing_event.set(Some(uid.clone()));
                
                wasm_bindgen_futures::spawn_local(async move {
                    let calendar_service = CalendarService::new();
                    
                    // Get password from stored credentials
                    let password = if let Ok(credentials_str) = LocalStorage::get::<String>("caldav_credentials") {
                        if let Ok(credentials) = serde_json::from_str::<serde_json::Value>(&credentials_str) {
                            credentials["password"].as_str().unwrap_or("").to_string()
                        } else {
                            String::new()
                        }
                    } else {
                        String::new()
                    };
                    
                    match calendar_service.refresh_event(&token, &password, &uid).await {
                        Ok(Some(refreshed_event)) => {
                            // If this is a recurring event, we need to regenerate all occurrences
                            let mut updated_events = (*events).clone();
                            
                            // First, remove all existing occurrences of this event
                            for (_, day_events) in updated_events.iter_mut() {
                                day_events.retain(|e| e.uid != uid);
                            }
                            
                            // Then, if it's a recurring event, generate new occurrences
                            if refreshed_event.recurrence_rule.is_some() {
                                let new_occurrences = CalendarService::expand_recurring_events(vec![refreshed_event.clone()]);
                                
                                // Add all new occurrences to the appropriate dates
                                for occurrence in new_occurrences {
                                    let date = occurrence.get_date();
                                    updated_events.entry(date)
                                        .or_insert_with(Vec::new)
                                        .push(occurrence);
                                }
                            } else {
                                // Non-recurring event, just add it to the appropriate date
                                let date = refreshed_event.get_date();
                                updated_events.entry(date)
                                    .or_insert_with(Vec::new)
                                    .push(refreshed_event);
                            }
                            
                            events.set(updated_events);
                        }
                        Ok(None) => {
                            // Event was deleted, remove it from the map
                            let mut updated_events = (*events).clone();
                            for (_, day_events) in updated_events.iter_mut() {
                                day_events.retain(|e| e.uid != uid);
                            }
                            events.set(updated_events);
                        }
                        Err(_err) => {
                            // Log error but don't show it to user - keep using cached event
                            // Silently fall back to cached event data
                        }
                    }
                    
                    refreshing_event.set(None);
                });
            }
        })
    };
    
    // Fetch events when component mounts
    {
        let events = events.clone();
        let loading = loading.clone();
        let error = error.clone();
        let auth_token = auth_token.clone();
        
        use_effect_with((), move |_| {
            if let Some(token) = auth_token {
                let events = events.clone();
                let loading = loading.clone();
                let error = error.clone();
                
                wasm_bindgen_futures::spawn_local(async move {
                    let calendar_service = CalendarService::new();
                    
                    // Get password from stored credentials
                    let password = if let Ok(credentials_str) = LocalStorage::get::<String>("caldav_credentials") {
                        if let Ok(credentials) = serde_json::from_str::<serde_json::Value>(&credentials_str) {
                            credentials["password"].as_str().unwrap_or("").to_string()
                        } else {
                            String::new()
                        }
                    } else {
                        String::new()
                    };
                    
                    match calendar_service.fetch_events_for_month(&token, &password, current_year, current_month).await {
                        Ok(calendar_events) => {
                            let grouped_events = CalendarService::group_events_by_date(calendar_events);
                            events.set(grouped_events);
                            loading.set(false);
                        }
                        Err(err) => {
                            error.set(Some(format!("Failed to load events: {}", err)));
                            loading.set(false);
                        }
                    }
                });
            } else {
                loading.set(false);
                error.set(Some("No authentication token found".to_string()));
            }
            
            || ()
        });
    }
    
    html! {
        <div class="calendar-view">
            {
                if *loading {
                    html! {
                        <div class="calendar-loading">
                            <p>{"Loading calendar events..."}</p>
                        </div>
                    }
                } else if let Some(err) = (*error).clone() {
                    let dummy_callback = Callback::from(|_: CalendarEvent| {});
                    html! {
                        <div class="calendar-error">
                            <p>{format!("Error: {}", err)}</p>
                            <Calendar events={HashMap::new()} on_event_click={dummy_callback} refreshing_event_uid={(*refreshing_event).clone()} />
                        </div>
                    }
                } else {
                    html! {
                        <Calendar events={(*events).clone()} on_event_click={on_event_click} refreshing_event_uid={(*refreshing_event).clone()} />
                    }
                }
            }
        </div>
    }
}