use yew::prelude::*;
use chrono::{Datelike, Local, NaiveDate, Duration};
use std::collections::HashMap;
use web_sys::MouseEvent;
use crate::services::calendar_service::UserInfo;
use crate::models::ical::VEvent;
use crate::components::{EventModal, ViewMode, CalendarHeader, MonthView, WeekView, CreateEventModal, EventCreationData};
use gloo_storage::{LocalStorage, Storage};

#[derive(Properties, PartialEq)]
pub struct CalendarProps {
    #[prop_or_default]
    pub events: HashMap<NaiveDate, Vec<VEvent>>,
    pub on_event_click: Callback<VEvent>,
    #[prop_or_default]
    pub refreshing_event_uid: Option<String>,
    #[prop_or_default]
    pub user_info: Option<UserInfo>,
    #[prop_or_default]
    pub on_event_context_menu: Option<Callback<(web_sys::MouseEvent, VEvent)>>,
    #[prop_or_default]
    pub on_calendar_context_menu: Option<Callback<(web_sys::MouseEvent, NaiveDate)>>,
    #[prop_or_default]
    pub view: ViewMode,
    #[prop_or_default]
    pub on_create_event_request: Option<Callback<EventCreationData>>,
    #[prop_or_default]
    pub on_event_update_request: Option<Callback<(VEvent, chrono::NaiveDateTime, chrono::NaiveDateTime, bool, Option<chrono::DateTime<chrono::Utc>>)>>,
    #[prop_or_default]
    pub context_menus_open: bool,
}

#[function_component]
pub fn Calendar(props: &CalendarProps) -> Html {
    let today = Local::now().date_naive();
    // Track the currently selected date (the actual day the user has selected)
    let selected_date = use_state(|| {
        // Try to load saved selected date from localStorage
        if let Ok(saved_date_str) = LocalStorage::get::<String>("calendar_selected_date") {
            if let Ok(saved_date) = NaiveDate::parse_from_str(&saved_date_str, "%Y-%m-%d") {
                saved_date
            } else {
                today
            }
        } else {
            // Check for old key for backward compatibility
            if let Ok(saved_date_str) = LocalStorage::get::<String>("calendar_current_month") {
                if let Ok(saved_date) = NaiveDate::parse_from_str(&saved_date_str, "%Y-%m-%d") {
                    saved_date
                } else {
                    today
                }
            } else {
                today
            }
        }
    });
    
    // Track the display date (what to show in the view)
    let current_date = use_state(|| {
        match props.view {
            ViewMode::Month => selected_date.with_day(1).unwrap_or(*selected_date),
            ViewMode::Week => *selected_date,
        }
    });
    let selected_event = use_state(|| None::<VEvent>);
    
    // State for create event modal
    let show_create_modal = use_state(|| false);
    let create_event_data = use_state(|| None::<(chrono::NaiveDate, chrono::NaiveTime, chrono::NaiveTime)>);
    
    // State for time increment snapping (15 or 30 minutes)
    let time_increment = use_state(|| {
        // Try to load saved time increment from localStorage
        if let Ok(saved_increment) = LocalStorage::get::<u32>("calendar_time_increment") {
            if saved_increment == 15 || saved_increment == 30 {
                saved_increment
            } else {
                15
            }
        } else {
            15
        }
    });
    
    // Handle view mode changes - adjust current_date format when switching between month/week
    {
        let current_date = current_date.clone();
        let selected_date = selected_date.clone();
        let view = props.view.clone();
        use_effect_with(view, move |view_mode| {
            let selected = *selected_date;
            let new_display_date = match view_mode {
                ViewMode::Month => selected.with_day(1).unwrap_or(selected),
                ViewMode::Week => selected, // Show the week containing the selected date
            };
            current_date.set(new_display_date);
            || {}
        });
    }
    
    let on_prev = {
        let current_date = current_date.clone();
        let selected_date = selected_date.clone();
        let view = props.view.clone();
        Callback::from(move |_: MouseEvent| {
            let (new_selected, new_display) = match view {
                ViewMode::Month => {
                    // Go to previous month, select the 1st day
                    let prev_month = *current_date - Duration::days(1);
                    let first_of_prev = prev_month.with_day(1).unwrap();
                    (first_of_prev, first_of_prev)
                },
                ViewMode::Week => {
                    // Go to previous week
                    let prev_week = *selected_date - Duration::weeks(1);
                    (prev_week, prev_week)
                },
            };
            selected_date.set(new_selected);
            current_date.set(new_display);
            let _ = LocalStorage::set("calendar_selected_date", new_selected.format("%Y-%m-%d").to_string());
        })
    };
    
    let on_next = {
        let current_date = current_date.clone();
        let selected_date = selected_date.clone();
        let view = props.view.clone();
        Callback::from(move |_: MouseEvent| {
            let (new_selected, new_display) = match view {
                ViewMode::Month => {
                    // Go to next month, select the 1st day
                    let next_month = if current_date.month() == 12 {
                        NaiveDate::from_ymd_opt(current_date.year() + 1, 1, 1).unwrap()
                    } else {
                        NaiveDate::from_ymd_opt(current_date.year(), current_date.month() + 1, 1).unwrap()
                    };
                    (next_month, next_month)
                },
                ViewMode::Week => {
                    // Go to next week
                    let next_week = *selected_date + Duration::weeks(1);
                    (next_week, next_week)
                },
            };
            selected_date.set(new_selected);
            current_date.set(new_display);
            let _ = LocalStorage::set("calendar_selected_date", new_selected.format("%Y-%m-%d").to_string());
        })
    };

    let on_today = {
        let current_date = current_date.clone();
        let selected_date = selected_date.clone();
        let view = props.view.clone();
        Callback::from(move |_| {
            let today = Local::now().date_naive();
            let (new_selected, new_display) = match view {
                ViewMode::Month => {
                    let first_of_today = today.with_day(1).unwrap();
                    (today, first_of_today) // Select today, but display the month
                },
                ViewMode::Week => (today, today), // Select and display today
            };
            selected_date.set(new_selected);
            current_date.set(new_display);
            let _ = LocalStorage::set("calendar_selected_date", new_selected.format("%Y-%m-%d").to_string());
        })
    };
    
    // Handle time increment toggle
    let on_time_increment_toggle = {
        let time_increment = time_increment.clone();
        Callback::from(move |_: MouseEvent| {
            let current = *time_increment;
            let next = if current == 15 { 30 } else { 15 };
            time_increment.set(next);
            let _ = LocalStorage::set("calendar_time_increment", next);
        })
    };
    
    // Handle drag-to-create event
    let on_create_event = {
        let show_create_modal = show_create_modal.clone();
        let create_event_data = create_event_data.clone();
        Callback::from(move |(_date, start_datetime, end_datetime): (NaiveDate, chrono::NaiveDateTime, chrono::NaiveDateTime)| {
            // For drag-to-create, we don't need the temporary event approach
            // Instead, just pass the local times directly via initial_time props
            create_event_data.set(Some((start_datetime.date(), start_datetime.time(), end_datetime.time())));
            show_create_modal.set(true);
        })
    };
    
    // Handle drag-to-move event
    let on_event_update = {
        let on_event_update_request = props.on_event_update_request.clone();
        Callback::from(move |(event, new_start, new_end, preserve_rrule, until_date): (VEvent, chrono::NaiveDateTime, chrono::NaiveDateTime, bool, Option<chrono::DateTime<chrono::Utc>>)| {
            if let Some(callback) = &on_event_update_request {
                callback.emit((event, new_start, new_end, preserve_rrule, until_date));
            }
        })
    };

    html! {
        <div class={classes!("calendar", match props.view { ViewMode::Week => Some("week-view"), _ => None })}>
            <CalendarHeader 
                current_date={*current_date}
                view_mode={props.view.clone()}
                on_prev={on_prev}
                on_next={on_next}
                on_today={on_today}
                time_increment={Some(*time_increment)}
                on_time_increment_toggle={Some(on_time_increment_toggle)}
            />
            
            {
                match props.view {
                    ViewMode::Month => {
                        let on_day_select = {
                            let selected_date = selected_date.clone();
                            Callback::from(move |date: NaiveDate| {
                                selected_date.set(date);
                                let _ = LocalStorage::set("calendar_selected_date", date.format("%Y-%m-%d").to_string());
                            })
                        };
                        
                        html! {
                            <MonthView
                                current_month={*current_date}
                                today={today}
                                events={props.events.clone()}
                                on_event_click={props.on_event_click.clone()}
                                refreshing_event_uid={props.refreshing_event_uid.clone()}
                                user_info={props.user_info.clone()}
                                on_event_context_menu={props.on_event_context_menu.clone()}
                                on_calendar_context_menu={props.on_calendar_context_menu.clone()}
                                selected_date={Some(*selected_date)}
                                on_day_select={Some(on_day_select)}
                            />
                        }
                    },
                    ViewMode::Week => html! {
                        <WeekView
                            current_date={*current_date}
                            today={today}
                            events={props.events.clone()}
                            on_event_click={props.on_event_click.clone()}
                            refreshing_event_uid={props.refreshing_event_uid.clone()}
                            user_info={props.user_info.clone()}
                            on_event_context_menu={props.on_event_context_menu.clone()}
                            on_calendar_context_menu={props.on_calendar_context_menu.clone()}
                            on_create_event={Some(on_create_event)}
                            on_create_event_request={props.on_create_event_request.clone()}
                            on_event_update={Some(on_event_update)}
                            context_menus_open={props.context_menus_open}
                            time_increment={*time_increment}
                        />
                    },
                }
            }
            
            // Event details modal
            <EventModal 
                event={(*selected_event).clone()}
                on_close={{
                    let selected_event_clone = selected_event.clone();
                    Callback::from(move |_| {
                        selected_event_clone.set(None);
                    })
                }}
            />
            
            // Create event modal
            <CreateEventModal
                is_open={*show_create_modal}
                selected_date={create_event_data.as_ref().map(|(date, _, _)| *date)}
                event_to_edit={None}
                available_calendars={props.user_info.as_ref().map(|info| info.calendars.clone()).unwrap_or_default()}
                initial_start_time={create_event_data.as_ref().map(|(_, start_time, _)| *start_time)}
                initial_end_time={create_event_data.as_ref().map(|(_, _, end_time)| *end_time)}
                on_close={{
                    let show_create_modal = show_create_modal.clone();
                    let create_event_data = create_event_data.clone();
                    Callback::from(move |_| {
                        show_create_modal.set(false);
                        create_event_data.set(None);
                    })
                }}
                on_create={{
                    let show_create_modal = show_create_modal.clone();
                    let create_event_data = create_event_data.clone();
                    let on_create_event_request = props.on_create_event_request.clone();
                    Callback::from(move |event_data: EventCreationData| {
                        show_create_modal.set(false);
                        create_event_data.set(None);
                        
                        // Emit the create event request to parent
                        if let Some(callback) = &on_create_event_request {
                            callback.emit(event_data);
                        }
                    })
                }}
                on_update={{
                    let show_create_modal = show_create_modal.clone();
                    let create_event_data = create_event_data.clone();
                    Callback::from(move |(_original_event, _updated_data): (VEvent, EventCreationData)| {
                        show_create_modal.set(false);
                        create_event_data.set(None);
                        // TODO: Handle actual event update
                    })
                }}
            />
        </div>
    }
}