"use client";

import { Card, CardContent } from "@/components/ui/card";
import { Badge } from "@/components/ui/badge";
import { useCalendar } from "./CalendarContext";
import {
  Calendar as CalendarIcon,
  Clock,
  MapPin,
  ExternalLink,
} from "lucide-react";
import { format, isSameDay, parseISO } from "date-fns";
import { ScrollArea } from "@/components/ui/scroll-area";
import { siteUrls } from "@/lib/config/sites";

function getEventDate(event: { start: { dateTime?: string; date?: string } }): Date {
  if (event.start.dateTime) {
    return parseISO(event.start.dateTime);
  }
  if (event.start.date) {
    return parseISO(event.start.date);
  }
  return new Date();
}

function formatEventTime(event: {
  start: { dateTime?: string; date?: string };
  end: { dateTime?: string; date?: string };
}): string {
  if (event.start.date && !event.start.dateTime) {
    return "All day";
  }

  const start = event.start.dateTime ? parseISO(event.start.dateTime) : null;
  const end = event.end.dateTime ? parseISO(event.end.dateTime) : null;

  if (!start) return "TBD";

  if (end) {
    return `${format(start, "h:mm a")} - ${format(end, "h:mm a")}`;
  }

  return format(start, "h:mm a");
}

function formatEventDate(event: {
  start: { dateTime?: string; date?: string };
}): string {
  if (event.start.dateTime) {
    return format(parseISO(event.start.dateTime), "EEEE, MMMM d, yyyy");
  }
  if (event.start.date) {
    return format(parseISO(event.start.date), "EEEE, MMMM d, yyyy");
  }
  return "TBD";
}

function getCalendarColor(calendarName: string): string {
  const colors: Record<string, string> = {
    personal: "bg-pink-500/10 text-pink-500 border-pink-500/20",
    work: "bg-blue-500/10 text-blue-500 border-blue-500/20",
    health: "bg-green-500/10 text-green-500 border-green-500/20",
    social: "bg-purple-500/10 text-purple-500 border-purple-500/20",
    family: "bg-yellow-500/10 text-yellow-500 border-yellow-500/20",
    task: "bg-orange-500/10 text-orange-500 border-orange-500/20",
  };

  const lower = calendarName.toLowerCase();
  for (const [key, color] of Object.entries(colors)) {
    if (lower.includes(key)) return color;
  }

  return "bg-muted text-muted-foreground border-muted";
}

function groupEventsByDate(events: ReturnType<typeof useCalendar>["events"]) {
  const groups: { date: Date; label: string; events: typeof events }[] = [];

  for (const event of events) {
    const eventDate = getEventDate(event);
    const today = new Date();
    today.setHours(0, 0, 0, 0);

    let label: string;
    if (isSameDay(eventDate, today)) {
      label = "Today";
    } else if (isSameDay(eventDate, new Date(today.getTime() + 86400000))) {
      label = "Tomorrow";
    } else {
      label = format(eventDate, "EEEE, MMMM d");
    }

    const existingGroup = groups.find((g) => isSameDay(g.date, eventDate));
    if (existingGroup) {
      existingGroup.events.push(event);
    } else {
      groups.push({ date: eventDate, label, events: [event] });
    }
  }

  return groups;
}

export function EventList() {
  const { events } = useCalendar();

  const groupedEvents = groupEventsByDate(events);

  if (events.length === 0) {
    return (
      <div className="text-center py-12 text-muted-foreground">
        <CalendarIcon className="w-12 h-12 mx-auto mb-4 opacity-50" />
        <p>No upcoming events</p>
        <p className="text-sm mt-1">Events from your Google Calendar will appear here</p>
      </div>
    );
  }

  return (
    <ScrollArea className="h-[600px] pr-4">
      <div className="space-y-6">
        {groupedEvents.map((group) => (
          <div key={group.label}>
            <h3 className="text-sm font-semibold text-muted-foreground mb-3 sticky top-0 bg-background py-2 z-10">
              {group.label}
            </h3>
            <div className="space-y-3">
              {group.events.map((event) => (
                <EventCard key={event.id} event={event} />
              ))}
            </div>
          </div>
        ))}
      </div>
    </ScrollArea>
  );
}

function EventCard({
  event,
}: {
  event: ReturnType<typeof useCalendar>["events"][0];
}) {
  const eventDate = getEventDate(event);
  const isAllDay = !!event.start.date && !event.start.dateTime;

  return (
    <Card className="group hover:shadow-md transition-shadow">
      <CardContent className="p-4">
        <div className="flex items-start gap-4">
          <div className="w-14 h-14 rounded-lg bg-secondary flex flex-col items-center justify-center shrink-0">
            <span className="text-xs text-muted-foreground uppercase">
              {format(eventDate, "MMM")}
            </span>
            <span className="text-lg font-bold">{format(eventDate, "d")}</span>
          </div>
          <div className="flex-1 min-w-0">
            <div className="flex items-center gap-2 flex-wrap">
              <h3 className="font-semibold truncate">{event.summary}</h3>
              <Badge variant="outline" className={getCalendarColor(event.calendarName)}>
                {event.calendarName}
              </Badge>
            </div>
            {event.description && (
              <p className="text-sm text-muted-foreground mt-1 line-clamp-2">
                {event.description}
              </p>
            )}
            <div className="flex items-center gap-4 mt-2 text-xs text-muted-foreground flex-wrap">
              <span className="flex items-center gap-1">
                <Clock className="w-3 h-3" />
                {formatEventTime(event)}
              </span>
              {!isAllDay && (
                <span className="flex items-center gap-1">
                  <CalendarIcon className="w-3 h-3" />
                  {formatEventDate(event)}
                </span>
              )}
              {event.location && (
                <span className="flex items-center gap-1">
                  <MapPin className="w-3 h-3" />
                  <span className="truncate max-w-[150px]">{event.location}</span>
                </span>
              )}
            </div>
          </div>
          <a
            href={`${siteUrls.googleCalendar}/calendar/event?eid=${btoa(
              event.id
            )}`}
            target="_blank"
            rel="noopener noreferrer"
            className="opacity-0 group-hover:opacity-100 transition-opacity shrink-0"
            title="Open in Google Calendar"
          >
            <ExternalLink className="w-4 h-4 text-muted-foreground hover:text-foreground" />
          </a>
        </div>
      </CardContent>
    </Card>
  );
}