"use client";

import { useEffect, useState } from "react";
import { useParams, useRouter } from "next/navigation";
import { useAuth } from "@/components/AuthProvider";
import { c2api } from "@/lib/c2api";
import type { TripRecord, TripEvent } from "@/lib/types";

// ---------------------------------------------------------------------------
// Formatting helpers
// ---------------------------------------------------------------------------

function fmtDate(iso: string) {
  return new Date(`${iso}T12:00:00`).toLocaleDateString("en-US", {
    month: "short", day: "numeric", year: "numeric",
  });
}

function fmtDayLabel(iso: string) {
  return new Date(`${iso}T12:00:00`).toLocaleDateString("en-US", {
    weekday: "long", month: "short", day: "numeric",
  });
}

function fmtTime(t: string | null) {
  if (!t) return null;
  const [h, m] = t.split(":").map(Number);
  const d = new Date();
  d.setHours(h, m, 0, 0);
  return d.toLocaleTimeString("en-US", { hour: "numeric", minute: "2-digit" });
}

function dateRange(start: string, end: string): string[] {
  const dates: string[] = [];
  const cur = new Date(`${start}T12:00:00`);
  const endDate = new Date(`${end}T12:00:00`);
  while (cur <= endDate) {
    dates.push(cur.toISOString().slice(0, 10));
    cur.setDate(cur.getDate() + 1);
  }
  return dates;
}

// ---------------------------------------------------------------------------
// Add Event modal
// ---------------------------------------------------------------------------

function AddEventModal({ trip, onClose, onAdd }: {
  trip: TripRecord;
  onClose: () => void;
  onAdd: (body: object) => Promise<void>;
}) {
  const [title,    setTitle]    = useState("");
  const [date,     setDate]     = useState(trip.start_date);
  const [time,     setTime]     = useState("");
  const [location, setLocation] = useState("");
  const [mapsLink, setMapsLink] = useState("");
  const [notes,    setNotes]    = useState("");
  const [saving,   setSaving]   = useState(false);
  const [error,    setError]    = useState<string | null>(null);

  async function handleSubmit(e: React.FormEvent) {
    e.preventDefault();
    setSaving(true);
    setError(null);
    try {
      await onAdd({
        title,
        date,
        time: time || null,
        location: location || null,
        maps_link: mapsLink || null,
        notes: notes || null,
      });
      onClose();
    } catch {
      setError("Failed to add event. Make sure the date is within the trip range.");
    } finally {
      setSaving(false);
    }
  }

  return (
    <div className="fixed inset-0 bg-black/60 flex items-center justify-center z-50">
      <form
        onSubmit={handleSubmit}
        className="bg-gray-900 border border-gray-700 rounded-xl p-6 w-full max-w-md space-y-4"
      >
        <h2 className="text-white font-bold">Add Event</h2>

        <div>
          <label className="text-xs text-gray-400 block mb-1">Title</label>
          <input
            required value={title} onChange={(e) => setTitle(e.target.value)}
            placeholder="Dinner on Broadway"
            className="w-full bg-gray-800 border border-gray-700 rounded-lg px-3 py-2 text-white text-sm focus:outline-none focus:border-indigo-500"
          />
        </div>

        <div className="grid grid-cols-2 gap-3">
          <div>
            <label className="text-xs text-gray-400 block mb-1">Date</label>
            <input
              required type="date"
              min={trip.start_date} max={trip.end_date}
              value={date} onChange={(e) => setDate(e.target.value)}
              className="w-full bg-gray-800 border border-gray-700 rounded-lg px-3 py-2 text-white text-sm focus:outline-none focus:border-indigo-500"
            />
          </div>
          <div>
            <label className="text-xs text-gray-400 block mb-1">Time (optional)</label>
            <input
              type="time" value={time} onChange={(e) => setTime(e.target.value)}
              className="w-full bg-gray-800 border border-gray-700 rounded-lg px-3 py-2 text-white text-sm focus:outline-none focus:border-indigo-500"
            />
          </div>
        </div>

        <div>
          <label className="text-xs text-gray-400 block mb-1">
            Location (optional — inherits trip location)
          </label>
          <input
            value={location} onChange={(e) => setLocation(e.target.value)}
            placeholder={trip.location}
            className="w-full bg-gray-800 border border-gray-700 rounded-lg px-3 py-2 text-white text-sm focus:outline-none focus:border-indigo-500"
          />
        </div>

        <div>
          <label className="text-xs text-gray-400 block mb-1">Google Maps link (optional)</label>
          <input
            type="url" value={mapsLink} onChange={(e) => setMapsLink(e.target.value)}
            placeholder="https://maps.google.com/…"
            className="w-full bg-gray-800 border border-gray-700 rounded-lg px-3 py-2 text-white text-sm focus:outline-none focus:border-indigo-500"
          />
        </div>

        <div>
          <label className="text-xs text-gray-400 block mb-1">Notes (optional)</label>
          <textarea
            value={notes} onChange={(e) => setNotes(e.target.value)} rows={2}
            className="w-full bg-gray-800 border border-gray-700 rounded-lg px-3 py-2 text-white text-sm focus:outline-none resize-none"
          />
        </div>

        {error && <p className="text-red-400 text-xs">{error}</p>}

        <div className="flex gap-3 justify-end">
          <button type="button" onClick={onClose} className="text-sm text-gray-400 hover:text-gray-200 px-4 py-2">
            Cancel
          </button>
          <button
            type="submit" disabled={saving}
            className="bg-indigo-600 hover:bg-indigo-500 disabled:opacity-50 text-white text-sm rounded-lg px-4 py-2"
          >
            {saving ? "Adding…" : "Add Event"}
          </button>
        </div>
      </form>
    </div>
  );
}

// ---------------------------------------------------------------------------
// Event card
// ---------------------------------------------------------------------------

function EventCard({ event, isAdmin, onDelete }: {
  event: TripEvent;
  isAdmin: boolean;
  onDelete: (id: string) => void;
}) {
  const time = fmtTime(event.time);
  const attendees = Object.values(event.attendees ?? {});

  return (
    <div className="flex gap-4 items-start">
      <div className="w-20 shrink-0 text-right">
        {time ? (
          <span className="text-gray-400 text-xs font-mono">{time}</span>
        ) : (
          <span className="text-gray-700 text-xs font-mono">—</span>
        )}
      </div>
      <div className="flex-1 min-w-0 pb-4 border-b border-gray-800">
        <div className="flex items-start justify-between gap-2">
          <p className="text-white text-sm font-medium">{event.title}</p>
          {isAdmin && (
            <button
              onClick={() => onDelete(event.event_id)}
              className="text-xs text-red-500 hover:text-red-400 transition-colors shrink-0"
            >
              Remove
            </button>
          )}
        </div>
        {!event.location_inherited && (
          <div className="flex items-center gap-1 mt-0.5">
            <p className="text-gray-500 text-xs">{event.location}</p>
            {event.maps_link && (
              <a
                href={event.maps_link}
                target="_blank"
                rel="noopener noreferrer"
                onClick={(e) => e.stopPropagation()}
                className="text-xs text-indigo-400 hover:text-indigo-300 transition-colors"
              >
                Maps
              </a>
            )}
          </div>
        )}
        {event.location_inherited && event.maps_link && (
          <a
            href={event.maps_link}
            target="_blank"
            rel="noopener noreferrer"
            className="text-xs text-indigo-400 hover:text-indigo-300 transition-colors mt-0.5 block"
          >
            Maps
          </a>
        )}
        {event.notes && (
          <p className="text-gray-500 text-xs mt-1 italic">{event.notes}</p>
        )}
        {attendees.length > 0 && (
          <p className="text-gray-600 text-xs mt-1">{attendees.join(", ")}</p>
        )}
      </div>
    </div>
  );
}

// ---------------------------------------------------------------------------
// Page
// ---------------------------------------------------------------------------

export default function TripDetailPage() {
  const { id }          = useParams<{ id: string }>();
  const router          = useRouter();
  const { isAdmin }     = useAuth();

  const [trip, setTrip]         = useState<(TripRecord & { events: TripEvent[] }) | null>(null);
  const [loading, setLoading]   = useState(true);
  const [showAdd, setShowAdd]   = useState(false);

  async function load() {
    try {
      const data = await c2api.getTrip(id);
      setTrip(data as TripRecord & { events: TripEvent[] });
    } catch (e) {
      console.error(e);
    } finally {
      setLoading(false);
    }
  }

  useEffect(() => { load(); }, [id]);

  async function handleDeleteTrip() {
    if (!trip) return;
    try {
      await c2api.deleteTrip(trip.trip_id);
      router.push("/trips");
    } catch (e) { console.error(e); }
  }

  async function handleDeleteEvent(eventId: string) {
    if (!trip) return;
    try {
      await c2api.deleteTripEvent(trip.trip_id, eventId);
      setTrip((prev) => prev ? { ...prev, events: prev.events.filter((e) => e.event_id !== eventId) } : prev);
    } catch (e) { console.error(e); }
  }

  async function handleAddEvent(body: object) {
    if (!trip) return;
    const event = await c2api.createTripEvent(trip.trip_id, body);
    setTrip((prev) => {
      if (!prev) return prev;
      const events = [...prev.events, event].sort((a, b) =>
        a.date.localeCompare(b.date) || (a.time ?? "").localeCompare(b.time ?? "")
      );
      return { ...prev, events };
    });
  }

  if (loading) {
    return <p className="text-gray-500 text-sm font-mono">Loading…</p>;
  }

  if (!trip) {
    return <p className="text-gray-500 text-sm font-mono">Trip not found.</p>;
  }

  const attendees = Object.values(trip.attendees ?? {});
  const eventsByDate: Record<string, TripEvent[]> = {};
  for (const e of trip.events ?? []) {
    (eventsByDate[e.date] ??= []).push(e);
  }
  const days = dateRange(trip.start_date, trip.end_date).filter((d) => eventsByDate[d]);

  return (
    <div className="space-y-8 max-w-2xl">
      {/* Back */}
      <button
        onClick={() => router.push("/trips")}
        className="text-sm font-mono text-gray-500 hover:text-gray-300 transition-colors"
      >
        ← Trips
      </button>

      {/* Header */}
      <div className="space-y-2">
        <div className="flex items-start justify-between gap-4">
          <h1 className="text-white text-2xl font-bold">{trip.name}</h1>
          {isAdmin && (
            <button
              onClick={handleDeleteTrip}
              className="text-xs text-red-500 hover:text-red-400 transition-colors shrink-0 mt-1"
            >
              Delete trip
            </button>
          )}
        </div>

        <div className="flex flex-wrap items-center gap-x-4 gap-y-1 text-sm text-gray-400">
          <span>{trip.location}</span>
          {trip.maps_link && (
            <a
              href={trip.maps_link}
              target="_blank"
              rel="noopener noreferrer"
              className="text-indigo-400 hover:text-indigo-300 text-xs transition-colors"
            >
              View on Maps
            </a>
          )}
          <span className="text-gray-600">•</span>
          <span className="font-mono text-xs">
            {fmtDate(trip.start_date)} — {fmtDate(trip.end_date)}
          </span>
        </div>

        {attendees.length > 0 && (
          <p className="text-gray-500 text-xs">
            Going: {attendees.join(", ")}
          </p>
        )}
      </div>

      {/* Itinerary */}
      <div className="space-y-8">
        <div className="flex items-center justify-between">
          <h2 className="text-sm font-mono text-gray-400 uppercase tracking-wider">Itinerary</h2>
          {isAdmin && (
            <button
              onClick={() => setShowAdd(true)}
              className="text-sm bg-gray-800 hover:bg-gray-700 text-gray-300 rounded-lg px-3 py-1.5 transition-colors"
            >
              + Add Event
            </button>
          )}
        </div>

        {days.length === 0 ? (
          <p className="text-gray-600 text-sm font-mono">
            No events yet.{isAdmin ? " Use \"Add Event\" to build the itinerary." : ""}
          </p>
        ) : (
          <div className="space-y-6">
            {days.map((day) => (
              <div key={day}>
                <p className="text-xs font-mono text-gray-500 uppercase tracking-wider mb-3">
                  {fmtDayLabel(day)}
                </p>
                <div className="space-y-0">
                  {(eventsByDate[day] ?? []).map((event) => (
                    <EventCard
                      key={event.event_id}
                      event={event}
                      isAdmin={isAdmin}
                      onDelete={handleDeleteEvent}
                    />
                  ))}
                </div>
              </div>
            ))}
          </div>
        )}
      </div>

      {showAdd && trip && (
        <AddEventModal
          trip={trip}
          onClose={() => setShowAdd(false)}
          onAdd={handleAddEvent}
        />
      )}
    </div>
  );
}