"use client"

import { useState, useEffect, useCallback, Component, type ReactNode } from "react"
import { useRouter } from "next/navigation"
import { Button } from "@/components/ui/button"
import { Card } from "@/components/ui/card"
import { Badge } from "@/components/ui/badge"
import { CalendarEvent, EventType } from "@/types"
import {
  Dialog, DialogContent, DialogHeader, DialogTitle, DialogFooter,
} from "@/components/ui/dialog"
import { Input } from "@/components/ui/input"
import { Label } from "@/components/ui/label"
import {
  Select, SelectContent, SelectItem, SelectTrigger, SelectValue,
} from "@/components/ui/select"
import { Textarea } from "@/components/ui/textarea"
import { cn } from "@/lib/utils"
import { useUser } from "@/providers/user-provider"
import { useNotifications } from "@/providers/notification-provider"
import { toast } from "sonner"
import {
  ChevronLeft, ChevronRight, Plus, Calendar, Clock, Phone,
  Video, Users, CheckCircle2, XCircle, RotateCcw, Loader2,
  ArrowUpRight, Zap, StickyNote,
} from "lucide-react"

const EVENT_ICONS: Record<EventType, React.ElementType> = {
  meeting: Users,
  call: Phone,
  chat: Video,
  follow_up: Clock,
  demo: Calendar,
  other: Calendar,
}

function eventVars(type: EventType) {
  return `--event-${type}`
}

function eventBgStyle(type: EventType): React.CSSProperties {
  const v = eventVars(type)
  return {
    backgroundColor: `hsl(var(${v}) / 0.1)`,
    color: `hsl(var(${v}))`,
    borderColor: `hsl(var(${v}) / 0.25)`,
  }
}

function eventDotStyle(type: EventType): React.CSSProperties {
  return { backgroundColor: `hsl(var(--event-${type}))` }
}

function getDaysInMonth(year: number, month: number) {
  return new Date(year, month + 1, 0).getDate()
}

function getFirstDayOfMonth(year: number, month: number) {
  return new Date(year, month, 1).getDay()
}

const MONTHS = ["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"]
const DAYS = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"]

function formatTime(iso: string) {
  return new Date(iso).toLocaleTimeString("en-US", { hour: "numeric", minute: "2-digit", hour12: true })
}

function formatDate(iso: string) {
  return new Date(iso).toLocaleDateString("en-US", { month: "short", day: "numeric", year: "numeric" })
}

export default function CalendarPage() {
  const router = useRouter()
  const { user } = useUser()
  const { addNotification } = useNotifications()
  const [events, setEvents] = useState<CalendarEvent[]>([])
  const [upcomingEvents, setUpcomingEvents] = useState<CalendarEvent[]>([])
  const [loading, setLoading] = useState(true)
  const [today] = useState(new Date())
  const [currentMonth, setCurrentMonth] = useState(today.getMonth())
  const [currentYear, setCurrentYear] = useState(today.getFullYear())
  const [selectedDate, setSelectedDate] = useState<Date | null>(null)
  const [dialogOpen, setDialogOpen] = useState(false)
  const [editingEvent, setEditingEvent] = useState<CalendarEvent | null>(null)
  const [detailEvent, setDetailEvent] = useState<CalendarEvent | null>(null)

  const [users, setUsers] = useState<{ id: string; name: string; email: string }[]>([])
  const [formTitle, setFormTitle] = useState("")
  const [formDescription, setFormDescription] = useState("")
  const [formType, setFormType] = useState<EventType>("meeting")
  const [formDate, setFormDate] = useState("")
  const [formTime, setFormTime] = useState("")
  const [formDuration, setFormDuration] = useState("30")
  const [formParticipantId, setFormParticipantId] = useState("")
  const [formSaving, setFormSaving] = useState(false)
  const [editNotes, setEditNotes] = useState(false)
  const [notesText, setNotesText] = useState("")
  const [notesSaving, setNotesSaving] = useState(false)

  const fetchMonthEvents = useCallback(async () => {
    const start = new Date(currentYear, currentMonth, 1).toISOString()
    const end = new Date(currentYear, currentMonth + 1, 0, 23, 59, 59).toISOString()
    const res = await fetch(`/api/events?start=${encodeURIComponent(start)}&end=${encodeURIComponent(end)}`)
    if (res.ok) {
      const data = await res.json()
      setEvents(data.events || [])
    }
  }, [currentYear, currentMonth])

  const fetchUpcomingEvents = useCallback(async () => {
    const start = new Date().toISOString()
    const end = new Date(Date.now() + 90 * 24 * 60 * 60 * 1000).toISOString()
    const res = await fetch(`/api/events?start=${encodeURIComponent(start)}&end=${encodeURIComponent(end)}&status=scheduled`)
    if (res.ok) {
      const data = await res.json()
      setUpcomingEvents((data.events || []).slice(0, 10))
    }
  }, [])

  useEffect(() => {
    if (!user) { router.push("/login"); return }
    fetch("/api/event-users")
      .then((r) => r.json())
      .then((data) => setUsers(data.users || []))
      .catch(() => {})
  }, [user, router])

  useEffect(() => {
    setLoading(true)
    fetchMonthEvents().catch(() => toast.error("Failed to load events")).finally(() => setLoading(false))
  }, [fetchMonthEvents])

  useEffect(() => {
    fetchUpcomingEvents().catch(() => {})
  }, [fetchUpcomingEvents])

  useEffect(() => {
    const interval = setInterval(() => {
      fetchMonthEvents().catch(() => {})
      fetchUpcomingEvents().catch(() => {})
    }, 15000)
    return () => clearInterval(interval)
  }, [fetchMonthEvents, fetchUpcomingEvents])

  const daysInMonth = getDaysInMonth(currentYear, currentMonth)
  const firstDay = getFirstDayOfMonth(currentYear, currentMonth)

  const prevMonth = () => {
    if (currentMonth === 0) { setCurrentMonth(11); setCurrentYear(currentYear - 1) }
    else setCurrentMonth(currentMonth - 1)
  }

  const nextMonth = () => {
    if (currentMonth === 11) { setCurrentMonth(0); setCurrentYear(currentYear + 1) }
    else setCurrentMonth(currentMonth + 1)
  }

  const getEventsForDay = useCallback((day: number) => {
    const dateStr = `${currentYear}-${String(currentMonth + 1).padStart(2, "0")}-${String(day).padStart(2, "0")}`
    return events.filter((e) => e.startTime.startsWith(dateStr))
  }, [events, currentYear, currentMonth])

  const isToday = (day: number) => {
    return today.getDate() === day && today.getMonth() === currentMonth && today.getFullYear() === currentYear
  }

  const openCreateDialog = (day?: number) => {
    setEditingEvent(null)
    setFormTitle("")
    setFormDescription("")
    setFormType("meeting")
    setFormDuration("30")
    setFormParticipantId("")
    const d = day ? new Date(currentYear, currentMonth, day) : new Date()
    setFormDate(d.toISOString().split("T")[0])
    setFormTime("10:00")
    setDialogOpen(true)
  }

  const openEditDialog = (event: CalendarEvent) => {
    setEditingEvent(event)
    setFormTitle(event.title)
    setFormDescription(event.description || "")
    setFormType(event.eventType)
    setFormDuration(String(event.durationMinutes || 30))
    setFormDate(new Date(event.startTime).toISOString().split("T")[0])
    setFormTime(new Date(event.startTime).toLocaleTimeString("en-US", { hour: "2-digit", minute: "2-digit", hour12: false }))
    setFormParticipantId(event.participantId || "")
    setDialogOpen(true)
  }

  const handleSave = async () => {
    if (!formTitle.trim() || !formDate || !formTime) {
      toast.error("Title, date, and time are required")
      return
    }

    setFormSaving(true)
    try {
      const startTime = new Date(`${formDate}T${formTime}:00`).toISOString()
      let endTime = null
      if (formDuration) {
        const end = new Date(startTime)
        end.setMinutes(end.getMinutes() + parseInt(formDuration))
        endTime = end.toISOString()
      }

      const body: Record<string, unknown> = {
        title: formTitle.trim(),
        description: formDescription.trim() || null,
        eventType: formType,
        startTime,
        endTime,
        durationMinutes: formDuration ? parseInt(formDuration) : null,
      }
      if (formParticipantId) body.participantId = formParticipantId

      let res
      if (editingEvent) {
        res = await fetch(`/api/events/${editingEvent.id}`, {
          method: "PATCH",
          headers: { "Content-Type": "application/json" },
          body: JSON.stringify(body),
        })
      } else {
        res = await fetch("/api/events", {
          method: "POST",
          headers: { "Content-Type": "application/json" },
          body: JSON.stringify(body),
        })
      }

      if (!res.ok) throw new Error("Failed to save")

      const data = await res.json()
      if (editingEvent) {
        setEvents((prev) => prev.map((e) => e.id === editingEvent.id ? { ...data.event, participant: e.participant, lead: e.lead } : e))
        toast.success("Event updated")
      } else {
        setEvents((prev) => [...prev, data.event])
        addNotification("event_scheduled", `Event created: ${formTitle}`, `Scheduled for ${formatDate(startTime)} at ${formatTime(startTime)}`, "/calendar")
        toast.success("Event created")
      }

      setDialogOpen(false)
    } catch {
      toast.error("Failed to save event")
    } finally {
      setFormSaving(false)
    }
  }

  const updateEventStatus = async (event: CalendarEvent, newStatus: string) => {
    try {
      const res = await fetch(`/api/events/${event.id}`, {
        method: "PATCH",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({ status: newStatus }),
      })
      if (!res.ok) throw new Error("Failed to update")
      const data = await res.json()
      setEvents((prev) => prev.map((e) => e.id === event.id ? { ...data.event, participant: e.participant, lead: e.lead } : e))
      toast.success(`Event ${newStatus}`)
      setDetailEvent(null)
    } catch {
      toast.error("Failed to update event")
    }
  }

  const saveNotes = async (event: CalendarEvent) => {
    if (notesText === (event.participantNotes || "")) { setEditNotes(false); return }
    setNotesSaving(true)
    try {
      const res = await fetch(`/api/events/${event.id}`, {
        method: "PATCH",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({ participantNotes: notesText || null }),
      })
      if (!res.ok) throw new Error("Failed to save")
      const data = await res.json()
      setEvents((prev) => prev.map((e) => e.id === event.id ? { ...data.event, participant: e.participant, lead: e.lead } : e))
      if (detailEvent && detailEvent.id === event.id) {
        setDetailEvent({ ...detailEvent, participantNotes: notesText || null })
      }
      toast.success("Notes saved")
      setEditNotes(false)
    } catch {
      toast.error("Failed to save notes")
    } finally {
      setNotesSaving(false)
    }
  }

  const deleteEvent = async (event: CalendarEvent) => {
    try {
      const res = await fetch(`/api/events/${event.id}`, { method: "DELETE" })
      if (!res.ok) throw new Error("Failed to delete")
      setEvents((prev) => prev.filter((e) => e.id !== event.id))
      toast.success("Event deleted")
      setDetailEvent(null)
      setDialogOpen(false)
    } catch {
      toast.error("Failed to delete event")
    }
  }

  const calendarDays: (number | null)[] = []
  for (let i = 0; i < firstDay; i++) calendarDays.push(null)
  for (let d = 1; d <= daysInMonth; d++) calendarDays.push(d)

  if (!user) return null

  return (
    <div className="flex flex-col h-[calc(100vh-4rem)] bg-gradient-to-b from-background via-background to-muted/20">
      {/* Header */}
      <div className="flex items-center justify-between px-6 py-3 border-b shrink-0 bg-gradient-to-r from-background via-accent/5 to-background backdrop-blur-sm shadow-[0_1px_3px_-1px_hsl(var(--border))]">
        <div className="flex items-center gap-4">
          <div className="flex items-center gap-2.5">
            <div className="p-2 rounded-lg bg-gradient-to-br from-primary/20 to-primary/5 text-primary shadow-sm ring-1 ring-primary/15">
              <Calendar className="h-4 w-4" />
            </div>
            <h1 className="text-lg font-bold tracking-tight">Calendar</h1>
          </div>
          <div className="flex items-center gap-1.5 p-0.5 rounded-lg border bg-card/60 shadow-sm">
            <Button variant="ghost" size="icon" className="h-7 w-7 rounded-md hover:bg-accent/60 hover:scale-105 active:scale-95 transition-all" onClick={prevMonth}>
              <ChevronLeft className="h-3.5 w-3.5" />
            </Button>
            <span className="text-sm font-bold min-w-[130px] text-center select-none tracking-tight px-1">
              {MONTHS[currentMonth]} {currentYear}
            </span>
            <Button variant="ghost" size="icon" className="h-7 w-7 rounded-md hover:bg-accent/60 hover:scale-105 active:scale-95 transition-all" onClick={nextMonth}>
              <ChevronRight className="h-3.5 w-3.5" />
            </Button>
          </div>
          <Button variant="ghost" size="sm" className="text-xs h-7 px-2 hover:bg-accent/40 hover:scale-105 active:scale-95 transition-all" onClick={() => { setCurrentMonth(today.getMonth()); setCurrentYear(today.getFullYear()) }}>
            Today
          </Button>
        </div>
        <Button onClick={() => openCreateDialog()} size="sm" className="shadow-sm hover:shadow-md hover:scale-[1.02] active:scale-[0.98] transition-all bg-gradient-to-r from-primary to-primary/90 h-9">
          <Plus className="h-4 w-4 mr-1.5" /> New Event
        </Button>
      </div>

      {/* Body - flex row with independent scroll */}
      <div className="flex-1 flex overflow-hidden p-4 lg:p-6 gap-4 lg:gap-6">
        {loading ? (
          <div className="flex-1 flex items-center justify-center">
            <div className="flex flex-col items-center gap-3">
              <div className="relative">
                <Loader2 className="h-8 w-8 animate-spin text-primary/60" />
                <div className="absolute inset-0 animate-pulse rounded-full bg-primary/5" />
              </div>
              <p className="text-sm text-muted-foreground animate-pulse">Loading calendar...</p>
            </div>
          </div>
        ) : (
          <>
            {/* Left: Calendar Grid */}
            <div className="flex-1 flex flex-col gap-4 min-w-0 overflow-hidden">
              {/* Stats bar */}
              <div className="flex items-center gap-3 shrink-0">
                <div className="flex items-center gap-2 px-3.5 py-2 rounded-lg bg-primary/5 border border-primary/10 shadow-sm">
                  <div className="h-2 w-2 rounded-full bg-primary" />
                  <span className="text-sm font-bold text-primary">{events.filter(e => e.status === "scheduled").length}</span>
                  <span className="text-[11px] text-primary/60 font-medium">scheduled</span>
                </div>
                <div className="flex items-center gap-2 px-3.5 py-2 rounded-lg bg-emerald-500/5 border border-emerald-500/10 shadow-sm">
                  <div className="h-2 w-2 rounded-full bg-emerald-500" />
                  <span className="text-sm font-bold text-emerald-600 dark:text-emerald-400">{events.filter(e => e.status === "completed").length}</span>
                  <span className="text-[11px] text-emerald-600/60 dark:text-emerald-400/60 font-medium">completed</span>
                </div>
                <div className="flex items-center gap-2 px-3.5 py-2 rounded-lg bg-muted/30 border shadow-sm">
                  <div className="h-2 w-2 rounded-full bg-muted-foreground/30" />
                  <span className="text-sm font-bold text-foreground/70">{events.length}</span>
                  <span className="text-[11px] text-muted-foreground/50 font-medium">total</span>
                </div>
              </div>

              {/* Calendar grid wrapper - scrollable */}
              <div className="flex-1 overflow-auto rounded-xl border bg-card shadow-sm">
                <div className="min-w-[600px]">
                  {/* Day headers */}
                  <div className="grid grid-cols-7 sticky top-0 z-10 bg-gradient-to-r from-muted/30 via-background to-muted/30 border-b border-border/40">
                    {DAYS.map((d, i) => (
                      <div key={d} className={cn(
                        "px-3 py-2.5 text-[11px] font-semibold text-muted-foreground/50 text-center tracking-widest uppercase",
                        i === 0 && "text-red-500/40 dark:text-red-400/40",
                        i === 6 && "text-red-500/40 dark:text-red-400/40",
                      )}>
                        {d}
                      </div>
                    ))}
                  </div>

                  {/* Day cells */}
                  <div className="grid grid-cols-7">
                    {calendarDays.map((day, i) => {
                      if (day === null) return <div key={`empty-${i}`} className="min-h-[110px] border-r border-b border-border/40 bg-gradient-to-b from-muted/[0.01] to-transparent" />
                      const dayEvents = getEventsForDay(day)
                      const todayMark = isToday(day)
                      const hasEvents = dayEvents.length > 0
                      return (
                        <div
                          key={day}
                          className={cn(
                            "min-h-[110px] p-1.5 border-r border-b border-border/40 cursor-pointer transition-all duration-150 relative group",
                            "hover:bg-accent/20 hover:shadow-[inset_0_0_0_1px_hsl(var(--border))]",
                            todayMark && "bg-gradient-to-b from-primary/[0.04] to-transparent",
                          )}
                          onClick={() => { setSelectedDate(new Date(currentYear, currentMonth, day)); openCreateDialog(day) }}
                        >
                          <div className="flex items-center justify-between mb-1 px-0.5">
                            <span
                              className={cn(
                                "inline-flex items-center justify-center h-6 w-6 text-xs font-medium rounded-full transition-all duration-200",
                                todayMark && "bg-primary text-primary-foreground text-[11px] font-bold shadow-md ring-2 ring-primary/30 scale-110",
                                !todayMark && "text-muted-foreground/70 group-hover:text-foreground",
                              )}
                            >
                              {day}
                            </span>
                            {hasEvents && (
                              <span className="text-[10px] font-semibold text-muted-foreground/30 group-hover:text-muted-foreground/60 transition-all">
                                {dayEvents.length}
                              </span>
                            )}
                          </div>

                          <div className="space-y-0.5">
                            {dayEvents.slice(0, 3).map((event) => {
                              const Icon = EVENT_ICONS[event.eventType]
                              return (
                                <button
                                  key={event.id}
                                  onClick={(e) => { e.stopPropagation(); setDetailEvent(event) }}
                                  className={cn(
                                    "w-full text-left text-[10px] leading-tight flex items-center gap-1 rounded transition-all duration-150",
                                    "hover:shadow-sm hover:scale-[1.02] active:scale-[0.97] group/pill",
                                    event.status !== "scheduled" && "opacity-40",
                                  )}
                                >
                                  <div className="w-0.5 h-5 rounded-full shrink-0" style={eventDotStyle(event.eventType)} />
                                  <div style={eventBgStyle(event.eventType)}
                                    className="flex-1 flex items-center gap-1 px-1.5 py-0.5 rounded-r min-w-0"
                                  >
                                    <Icon className="h-2 w-2 shrink-0 opacity-50" />
                                    <span className="truncate font-medium">{event.title}</span>
                                  </div>
                                </button>
                              )
                            })}
                            {dayEvents.length > 3 && (
                              <button
                                onClick={(e) => { e.stopPropagation() }}
                                className="text-[10px] text-muted-foreground/40 hover:text-muted-foreground pl-0.5 font-semibold transition-colors"
                              >
                                +{dayEvents.length - 3} more
                              </button>
                            )}
                          </div>
                        </div>
                      )
                    })}
                  </div>
                </div>
              </div>
            </div>

            {/* Right: Upcoming sidebar */}
            <div className="w-72 lg:w-80 shrink-0 flex flex-col gap-4 overflow-y-auto">
              <div className="flex items-center justify-between shrink-0">
                <h2 className="text-sm font-bold flex items-center gap-2 tracking-tight">
                  <ArrowUpRight className="h-4 w-4 text-primary/70" />
                  Upcoming
                </h2>
                {upcomingEvents.length > 0 && (
                  <Badge variant="secondary" className="text-[10px] font-semibold px-2 py-0.5 ring-1 ring-border/50">
                    {upcomingEvents.length}
                  </Badge>
                )}
              </div>

              {upcomingEvents.length === 0 ? (
                <Card className="p-6 border-dashed bg-card/50">
                  <div className="flex flex-col items-center gap-2.5 text-center">
                    <div className="p-3 rounded-xl bg-gradient-to-br from-muted/50 to-muted/20 ring-1 ring-border/20">
                      <Calendar className="h-6 w-6 text-muted-foreground/30" />
                    </div>
                    <div>
                      <p className="text-sm font-medium text-muted-foreground">No upcoming events</p>
                      <p className="text-[11px] text-muted-foreground/40 mt-0.5">Schedule one to get started</p>
                    </div>
                    <Button variant="outline" size="sm" onClick={() => openCreateDialog()} className="hover:scale-105 active:scale-95 transition-all shadow-sm">
                      <Plus className="h-3 w-3 mr-1.5" /> Schedule event
                    </Button>
                  </div>
                </Card>
              ) : (
                <div className="space-y-2">
                  {upcomingEvents.map((event) => {
                    const Icon = EVENT_ICONS[event.eventType]
                    return (
                      <button
                        key={event.id}
                        onClick={() => setDetailEvent(event)}
                        className={cn(
                          "w-full text-left rounded-lg border bg-card/80 hover:bg-card transition-all duration-150 overflow-hidden",
                          "hover:shadow-md hover:border-accent-foreground/10 active:scale-[0.98]",
                        )}
                      >
                        <div className="flex">
                          <div className="w-0.5 shrink-0" style={eventDotStyle(event.eventType)} />
                          <div className="flex-1 p-3">
                            <div className="flex items-start gap-2.5">
                              <div className={cn(
                                "p-1.5 rounded shrink-0 ring-1 ring-border/20",
                                event.userId === user?.id ? "bg-primary/5" : "bg-muted",
                              )}>
                                <Icon className={cn(
                                  "h-3.5 w-3.5",
                                  event.userId === user?.id ? "text-primary/60" : "text-muted-foreground/40",
                                )} />
                              </div>
                              <div className="flex-1 min-w-0">
                                <div className="flex items-center justify-between gap-1.5">
                                  <p className="text-sm font-semibold truncate">{event.title}</p>
                                  <span className={cn(
                                    "text-[9px] font-semibold px-1.5 py-0.5 rounded capitalize shrink-0",
                                    event.status === "scheduled" && "bg-primary/10 text-primary",
                                    event.status === "completed" && "bg-emerald-500/10 text-emerald-600 dark:text-emerald-400",
                                    event.status === "cancelled" && "bg-red-500/10 text-red-600 dark:text-red-400",
                                  )}>
                                    {event.status}
                                  </span>
                                </div>
                                <div className="flex items-center gap-1.5 mt-1 text-[10px] text-muted-foreground/60 font-medium">
                                  <Clock className="h-3 w-3" />
                                  {formatDate(event.startTime)}
                                  <span className="text-muted-foreground/20">·</span>
                                  {formatTime(event.startTime)}
                                </div>
                                {event.durationMinutes && (
                                  <div className="flex items-center gap-1 mt-0.5 text-[10px] text-muted-foreground/40 font-medium">
                                    <Zap className="h-2.5 w-2.5" />
                                    {event.durationMinutes} min
                                  </div>
                                )}
                                <div className="flex items-center gap-1 mt-1">
                                  <span className={cn(
                                    "h-3.5 w-3.5 rounded-full text-[7px] flex items-center justify-center font-bold ring-1",
                                    event.userId === user?.id
                                      ? "bg-primary/10 text-primary ring-primary/20"
                                      : "bg-muted text-muted-foreground/60 ring-border",
                                  )}>
                                    {event.userId === user?.id
                                      ? (event.participant?.name.charAt(0) || "?")
                                      : (event.creator?.name.charAt(0) || "?")}
                                  </span>
                                  <span className="text-[10px] text-muted-foreground/60 font-medium">
                                    {event.userId === user?.id
                                      ? (event.participant?.name || "No participant")
                                      : (event.creator?.name || "Unknown")}
                                  </span>
                                </div>
                              </div>
                            </div>
                          </div>
                        </div>
                      </button>
                    )
                  })}
                </div>
              )}
            </div>
          </>
        )}
      </div>

      {/* Create/Edit Dialog */}
      <Dialog open={dialogOpen} onOpenChange={setDialogOpen}>
        <DialogContent className="sm:max-w-[520px]">
          <DialogHeader>
            <div className="flex items-center gap-3">
              <div className={cn(
                "p-3 rounded-xl border shadow-sm",
                editingEvent
                  ? "bg-gradient-to-br from-muted to-muted/50 text-muted-foreground border-border"
                  : "bg-gradient-to-br from-primary/15 to-primary/5 text-primary border-primary/20",
              )}>
                {editingEvent ? <Clock className="h-5 w-5" /> : <Plus className="h-5 w-5" />}
              </div>
              <div>
                <DialogTitle className="text-lg font-bold">{editingEvent ? "Edit Event" : "Create Event"}</DialogTitle>
                <p className="text-xs text-muted-foreground/60 mt-0.5">
                  {editingEvent ? "Update the event details below" : "Fill in the details for your new event"}
                </p>
              </div>
            </div>
          </DialogHeader>
          <div className="space-y-5 py-4">
            <div className="space-y-2">
              <Label htmlFor="title" className="text-xs font-semibold">Title</Label>
              <Input id="title" value={formTitle} onChange={(e) => setFormTitle(e.target.value)} placeholder="e.g. Product demo with client" className="h-10" />
            </div>
            <div className="grid grid-cols-2 gap-4">
              <div className="space-y-2">
                <Label htmlFor="date" className="text-xs font-semibold">Date</Label>
                <Input id="date" type="date" value={formDate} onChange={(e) => setFormDate(e.target.value)} className="h-10" />
              </div>
              <div className="space-y-2">
                <Label htmlFor="time" className="text-xs font-semibold">Time</Label>
                <Input id="time" type="time" value={formTime} onChange={(e) => setFormTime(e.target.value)} className="h-10" />
              </div>
            </div>
            <div className="grid grid-cols-2 gap-4">
              <div className="space-y-2">
                <Label htmlFor="type" className="text-xs font-semibold">Type</Label>
                <Select value={formType} onValueChange={(v: EventType) => setFormType(v)}>
                  <SelectTrigger id="type" className="h-10">
                    <SelectValue />
                  </SelectTrigger>
                  <SelectContent>
                    <SelectItem value="meeting">Meeting</SelectItem>
                    <SelectItem value="call">Call</SelectItem>
                    <SelectItem value="chat">Video Chat</SelectItem>
                    <SelectItem value="follow_up">Follow Up</SelectItem>
                    <SelectItem value="demo">Demo</SelectItem>
                    <SelectItem value="other">Other</SelectItem>
                  </SelectContent>
                </Select>
              </div>
              <div className="space-y-2">
                <Label htmlFor="duration" className="text-xs font-semibold">Duration</Label>
                <Select value={formDuration} onValueChange={setFormDuration}>
                  <SelectTrigger id="duration" className="h-10">
                    <SelectValue />
                  </SelectTrigger>
                  <SelectContent>
                    <SelectItem value="15">15 min</SelectItem>
                    <SelectItem value="30">30 min</SelectItem>
                    <SelectItem value="45">45 min</SelectItem>
                    <SelectItem value="60">1 hour</SelectItem>
                    <SelectItem value="90">1.5 hours</SelectItem>
                    <SelectItem value="120">2 hours</SelectItem>
                  </SelectContent>
                </Select>
              </div>
            </div>
            <div className="space-y-2">
              <Label htmlFor="participant" className="text-xs font-semibold">Participant</Label>
              <Select value={formParticipantId || "__none__"} onValueChange={(v) => setFormParticipantId(v === "__none__" ? "" : v)}>
                <SelectTrigger id="participant" className="h-10">
                  <SelectValue placeholder="Select a participant…" />
                </SelectTrigger>
                <SelectContent>
                  <SelectItem value="__none__">None</SelectItem>
                  {users.map((u) => (
                    <SelectItem key={u.id} value={u.id}>
                      {u.name} ({u.email})
                    </SelectItem>
                  ))}
                </SelectContent>
              </Select>
            </div>
            <div className="space-y-2">
              <Label htmlFor="description" className="text-xs font-semibold">Description</Label>
              <Textarea id="description" value={formDescription} onChange={(e) => setFormDescription(e.target.value)} placeholder="Add any notes or agenda items..." rows={3} className="resize-none" />
            </div>
          </div>
          <DialogFooter className="flex items-center justify-between border-t pt-4">
            <div>
              {editingEvent && (
                <Button variant="destructive" size="sm" onClick={() => deleteEvent(editingEvent)} className="shadow-sm">
                  Delete event
                </Button>
              )}
            </div>
            <div className="flex gap-2">
              <Button variant="outline" onClick={() => setDialogOpen(false)}>Cancel</Button>
              <Button onClick={handleSave} disabled={formSaving} className="shadow-sm">
                {formSaving && <Loader2 className="h-4 w-4 animate-spin mr-2" />}
                {editingEvent ? "Update Event" : "Create Event"}
              </Button>
            </div>
          </DialogFooter>
        </DialogContent>
      </Dialog>

      {/* Event Detail Dialog */}
      <Dialog open={!!detailEvent} onOpenChange={(open) => { if (!open) setDetailEvent(null) }}>
        {detailEvent && (
          <DialogContent className="sm:max-w-[460px]">
            <DialogHeader>
              <div className="flex items-center gap-3">
                <div className="p-3 rounded-xl border shadow-sm" style={eventBgStyle(detailEvent.eventType)}>
                  {(() => { const Icon = EVENT_ICONS[detailEvent.eventType]; return Icon ? <Icon className="h-5 w-5" /> : <Calendar className="h-5 w-5" /> })()}
                </div>
                <div className="flex-1 min-w-0">
                  <DialogTitle className="text-lg font-bold truncate">{detailEvent.title}</DialogTitle>
                  <span className={cn(
                    "inline-flex text-[10px] font-semibold px-2 py-0.5 rounded-full capitalize mt-0.5 ring-1",
                    detailEvent.status === "scheduled" && "bg-primary/10 text-primary ring-primary/20",
                    detailEvent.status === "completed" && "bg-emerald-500/10 text-emerald-600 dark:text-emerald-400 ring-emerald-500/20",
                    detailEvent.status === "cancelled" && "bg-red-500/10 text-red-600 dark:text-red-400 ring-red-500/20",
                  )}>
                    {detailEvent.status}
                  </span>
                </div>
              </div>
            </DialogHeader>
            <div className="space-y-4">
              {/* Date / Time */}
              <div className="grid grid-cols-2 gap-3">
                <div className="p-3.5 rounded-xl bg-gradient-to-br from-muted/50 to-muted/20 border shadow-sm">
                  <div className="flex items-center gap-2 text-[10px] font-semibold text-muted-foreground/50 uppercase tracking-wider mb-1.5">
                    <Calendar className="h-3.5 w-3.5" />
                    Date
                  </div>
                  <p className="text-sm font-bold">{formatDate(detailEvent.startTime)}</p>
                </div>
                <div className="p-3.5 rounded-xl bg-gradient-to-br from-muted/50 to-muted/20 border shadow-sm">
                  <div className="flex items-center gap-2 text-[10px] font-semibold text-muted-foreground/50 uppercase tracking-wider mb-1.5">
                    <Clock className="h-3.5 w-3.5" />
                    Time
                  </div>
                  <p className="text-sm font-bold">{formatTime(detailEvent.startTime)}</p>
                </div>
              </div>

              {/* Duration + Type */}
              <div className="grid grid-cols-2 gap-3">
                {detailEvent.durationMinutes && (
                  <div className="p-3.5 rounded-xl bg-gradient-to-br from-muted/50 to-muted/20 border shadow-sm">
                    <div className="flex items-center gap-2 text-[10px] font-semibold text-muted-foreground/50 uppercase tracking-wider mb-1.5">
                      <Zap className="h-3.5 w-3.5" />
                      Duration
                    </div>
                    <p className="text-sm font-bold">{detailEvent.durationMinutes} min</p>
                  </div>
                )}
                <div className="p-3.5 rounded-xl bg-gradient-to-br from-muted/50 to-muted/20 border shadow-sm">
                  <div className="flex items-center gap-2 text-[10px] font-semibold text-muted-foreground/50 uppercase tracking-wider mb-1.5 capitalize">
                    {(() => { const Icon = EVENT_ICONS[detailEvent.eventType]; return Icon ? <Icon className="h-3.5 w-3.5" /> : <Calendar className="h-3.5 w-3.5" /> })()}
                    Type
                  </div>
                  <p className="text-sm font-bold capitalize">{detailEvent.eventType.replace("_", " ")}</p>
                </div>
              </div>

              {/* Description */}
              {detailEvent.description && (
                <div className="p-3.5 rounded-xl bg-gradient-to-br from-muted/50 to-muted/20 border shadow-sm">
                  <p className="text-[10px] font-semibold text-muted-foreground/50 uppercase tracking-wider mb-1.5">Description</p>
                  <p className="text-sm whitespace-pre-wrap leading-relaxed">{detailEvent.description}</p>
                </div>
              )}

              {/* Linked lead */}
              {detailEvent.lead && (
                <div className="p-3.5 rounded-xl bg-gradient-to-br from-muted/50 to-muted/20 border shadow-sm">
                  <p className="text-[10px] font-semibold text-muted-foreground/50 uppercase tracking-wider mb-1.5">Linked Lead</p>
                  <p className="text-sm font-bold">{detailEvent.lead.contactName} — {detailEvent.lead.companyName}</p>
                </div>
              )}

              {/* Organizer & Participant - cross-linked */}
              <div className="grid grid-cols-2 gap-3">
                <div className="p-3.5 rounded-xl bg-gradient-to-br from-muted/50 to-muted/20 border shadow-sm">
                  <p className="text-[10px] font-semibold text-muted-foreground/50 uppercase tracking-wider mb-1.5 flex items-center gap-1.5">
                    <Users className="h-3 w-3" />
                    {detailEvent.userId === user?.id ? "You (Organizer)" : "Organizer"}
                  </p>
                  <p className="text-sm font-bold flex items-center gap-2">
                    <span className="h-6 w-6 rounded-full bg-muted text-muted-foreground text-[10px] flex items-center justify-center font-bold ring-1 ring-border">
                      {detailEvent.creator?.name.charAt(0).toUpperCase() || "?"}
                    </span>
                    <span className="truncate">{detailEvent.creator?.name || "Unknown"}</span>
                    {detailEvent.creator?.role && (
                      <span className="text-[10px] font-medium text-muted-foreground/50 capitalize shrink-0">({detailEvent.creator.role})</span>
                    )}
                  </p>
                </div>
                <div className="p-3.5 rounded-xl bg-gradient-to-br from-primary/5 to-primary/[0.02] border shadow-sm">
                  <p className="text-[10px] font-semibold text-muted-foreground/50 uppercase tracking-wider mb-1.5 flex items-center gap-1.5">
                    <Users className="h-3 w-3" />
                    {detailEvent.participantId === user?.id ? "You (Participant)" : "Participant"}
                  </p>
                  {detailEvent.participant ? (
                    <p className="text-sm font-bold flex items-center gap-2">
                      <span className="h-6 w-6 rounded-full bg-primary/10 text-primary text-[10px] flex items-center justify-center font-bold ring-1 ring-primary/20">
                        {detailEvent.participant.name.charAt(0).toUpperCase()}
                      </span>
                      <span className="truncate">{detailEvent.participant.name}</span>
                      {detailEvent.participant.role && (
                        <span className="text-[10px] font-medium text-muted-foreground/50 capitalize shrink-0">({detailEvent.participant.role})</span>
                      )}
                    </p>
                  ) : (
                    <p className="text-sm text-muted-foreground/50 italic">No participant</p>
                  )}
                </div>
              </div>

              {/* Participant Notes (editable by both parties) */}
              <div className="p-3.5 rounded-xl bg-gradient-to-br from-muted/50 to-muted/20 border shadow-sm">
                <div className="flex items-center justify-between mb-1.5">
                  <p className="text-[10px] font-semibold text-muted-foreground/50 uppercase tracking-wider flex items-center gap-1.5">
                    <StickyNote className="h-3 w-3" />
                    Notes
                  </p>
                  {!editNotes && (
                    <Button variant="ghost" size="sm" className="h-7 text-[11px] font-semibold hover:bg-accent/40" onClick={() => { setNotesText(detailEvent.participantNotes || ""); setEditNotes(true) }}>
                      {detailEvent.participantNotes ? "Edit" : "Add note"}
                    </Button>
                  )}
                </div>
                {editNotes ? (
                  <div className="space-y-2.5">
                    <Textarea value={notesText} onChange={(e) => setNotesText(e.target.value)} rows={3} className="resize-none text-sm" placeholder="Add your notes about this event…" />
                    <div className="flex gap-2 justify-end">
                      <Button variant="ghost" size="sm" onClick={() => setEditNotes(false)} disabled={notesSaving}>Cancel</Button>
                      <Button size="sm" onClick={() => saveNotes(detailEvent)} disabled={notesSaving} className="shadow-sm">
                        {notesSaving && <Loader2 className="h-3 w-3 animate-spin mr-1" />}
                        Save
                      </Button>
                    </div>
                  </div>
                ) : detailEvent.participantNotes ? (
                  <p className="text-sm whitespace-pre-wrap leading-relaxed font-medium">{detailEvent.participantNotes}</p>
                ) : (
                  <p className="text-sm text-muted-foreground/40 italic font-medium">No notes yet</p>
                )}
              </div>
            </div>
            <DialogFooter className="flex items-center gap-2 border-t pt-4">
              {detailEvent.status === "scheduled" && (
                <>
                  <Button variant="default" size="sm" onClick={() => updateEventStatus(detailEvent, "completed")} className="shadow-sm">
                    <CheckCircle2 className="h-4 w-4 mr-1.5" /> Complete
                  </Button>
                  <Button variant="outline" size="sm" onClick={() => updateEventStatus(detailEvent, "cancelled")}>
                    <XCircle className="h-4 w-4 mr-1.5" /> Cancel
                  </Button>
                  <Button variant="outline" size="sm" onClick={() => { setDetailEvent(null); openEditDialog(detailEvent) }}>
                    Edit
                  </Button>
                </>
              )}
              {detailEvent.status === "completed" && (
                <Button variant="outline" size="sm" onClick={() => updateEventStatus(detailEvent, "scheduled")}>
                  <RotateCcw className="h-4 w-4 mr-1.5" /> Reopen
                </Button>
              )}
            </DialogFooter>
          </DialogContent>
        )}
      </Dialog>
    </div>
  )
}
