"use client"

import { useMemo, useRef, useState } from "react"
import { X } from "lucide-react"
import { ContactAvatar } from "@/components/gmail/contacts/contact-avatar"
import { Input } from "@/components/ui/input"
import { useContactsList } from "@/lib/contacts/use-contacts-list"
import { fullContactDisplayName } from "@/lib/contacts/types"
import type { AgendaEventAttendee } from "@/lib/agenda/agenda-types"
import { cn } from "@/lib/utils"

const EMAIL_RE = /^[^\s@]+@[^\s@]+\.[^\s@]+$/

interface Suggestion {
  email: string
  name: string
  avatarUrl?: string
}

/** Champ « Ajouter des invités » avec autocomplétion sur le carnet d'adresses. */
export function AgendaGuestPicker({
  attendees,
  onChange,
  organizerEmail,
  tabIndex,
}: {
  attendees: AgendaEventAttendee[]
  onChange: (attendees: AgendaEventAttendee[]) => void
  organizerEmail?: string
  tabIndex?: number
}) {
  const [query, setQuery] = useState("")
  const [focused, setFocused] = useState(false)
  const [activeIndex, setActiveIndex] = useState(0)
  const blurTimer = useRef<number | null>(null)
  const { contacts } = useContactsList()

  const suggestions: Suggestion[] = useMemo(() => {
    const q = query.trim().toLowerCase()
    if (q.length < 1) return []
    const taken = new Set(attendees.map((a) => a.email.toLowerCase()))
    if (organizerEmail) taken.add(organizerEmail.toLowerCase())
    const out: Suggestion[] = []
    for (const contact of contacts) {
      const name = fullContactDisplayName(contact)
      for (const { value: email } of contact.emails) {
        if (!email || taken.has(email.toLowerCase())) continue
        if (
          name.toLowerCase().includes(q) ||
          email.toLowerCase().includes(q)
        ) {
          out.push({ email, name: name || email, avatarUrl: contact.avatarUrl })
        }
      }
      if (out.length >= 6) break
    }
    return out
  }, [contacts, query, attendees, organizerEmail])

  const addAttendee = (s: Suggestion) => {
    onChange([...attendees, { email: s.email, name: s.name, status: "NEEDS-ACTION" }])
    setQuery("")
    setActiveIndex(0)
  }

  const tryAddRaw = () => {
    const email = query.trim().replace(/[,;]$/, "")
    if (!EMAIL_RE.test(email)) return false
    if (attendees.some((a) => a.email.toLowerCase() === email.toLowerCase())) {
      setQuery("")
      return true
    }
    addAttendee({ email, name: email })
    return true
  }

  const showSuggestions = focused && (suggestions.length > 0 || EMAIL_RE.test(query.trim()))

  return (
    <div className="flex flex-col gap-1.5">
      <div className="relative">
        <Input
          value={query}
          placeholder="Ajouter des invités"
          tabIndex={tabIndex}
          onChange={(e) => {
            setQuery(e.target.value)
            setActiveIndex(0)
          }}
          onFocus={() => {
            if (blurTimer.current) window.clearTimeout(blurTimer.current)
            setFocused(true)
          }}
          onBlur={() => {
            blurTimer.current = window.setTimeout(() => setFocused(false), 150)
          }}
          onKeyDown={(e) => {
            if (e.key === "ArrowDown") {
              e.preventDefault()
              setActiveIndex((i) => Math.min(i + 1, suggestions.length - 1))
            } else if (e.key === "ArrowUp") {
              e.preventDefault()
              setActiveIndex((i) => Math.max(i - 1, 0))
            } else if (e.key === "Enter") {
              e.preventDefault()
              if (suggestions[activeIndex]) addAttendee(suggestions[activeIndex])
              else tryAddRaw()
            } else if ((e.key === "," || e.key === ";") && query.trim()) {
              e.preventDefault()
              tryAddRaw()
            }
          }}
        />
        {showSuggestions && (
          <div className="absolute top-full right-0 left-0 z-50 mt-1 overflow-hidden rounded-lg border border-border/60 bg-popover py-1 shadow-lg">
            {suggestions.map((s, i) => (
              <button
                key={s.email}
                type="button"
                className={cn(
                  "flex w-full items-center gap-2.5 px-3 py-1.5 text-left",
                  i === activeIndex ? "bg-mail-nav-hover" : "hover:bg-mail-nav-hover",
                )}
                onMouseDown={(e) => {
                  e.preventDefault()
                  addAttendee(s)
                }}
              >
                <ContactAvatar name={s.name} email={s.email} avatarUrl={s.avatarUrl} size="xs" />
                <span className="min-w-0">
                  <span className="block truncate text-sm">{s.name}</span>
                  <span className="block truncate text-xs text-muted-foreground">
                    {s.email}
                  </span>
                </span>
              </button>
            ))}
            {suggestions.length === 0 && EMAIL_RE.test(query.trim()) && (
              <button
                type="button"
                className="flex w-full items-center gap-2 px-3 py-1.5 text-left text-sm hover:bg-mail-nav-hover"
                onMouseDown={(e) => {
                  e.preventDefault()
                  tryAddRaw()
                }}
              >
                Ajouter « {query.trim()} »
              </button>
            )}
          </div>
        )}
      </div>

      {attendees.length > 0 && (
        <div className="flex flex-col gap-1">
          {attendees.map((a) => (
            <div
              key={a.email}
              className="group flex items-center gap-2.5 rounded-lg px-1.5 py-1 hover:bg-mail-nav-hover"
            >
              <ContactAvatar name={a.name || a.email} email={a.email} size="xs" />
              <span className="min-w-0 flex-1">
                <span className="block truncate text-sm">{a.name || a.email}</span>
                {a.name && a.name !== a.email && (
                  <span className="block truncate text-xs text-muted-foreground">
                    {a.email}
                  </span>
                )}
              </span>
              <button
                type="button"
                aria-label={`Retirer ${a.email}`}
                className="rounded-full p-1 text-muted-foreground opacity-0 group-hover:opacity-100 hover:bg-black/5 dark:hover:bg-white/10"
                onClick={() => onChange(attendees.filter((x) => x.email !== a.email))}
              >
                <X className="size-4" />
              </button>
            </div>
          ))}
        </div>
      )}
    </div>
  )
}