"use client"

import { AnimatePresence, motion } from "motion/react"
import { useEffect, useRef, useState } from "react"
import { ArrowUpIcon, MessageCircleIcon, XIcon } from "lucide-react"
import { cn } from "@/lib/utils"
import { brandName } from "../../lib/content"
import type { TemplateContent } from "../../lib/types"
import { useAiAccess } from "../access-context"
import { BookingCard } from "./booking-card"
import { useAiChat } from "./use-ai-chat"

const ease = [0.22, 1, 0.36, 1] as const
const QUICK_REPLIES = ["Wie sind Ihre Öffnungszeiten?", "Ich möchte einen Termin vereinbaren", "Was bieten Sie an?"]

// Chat-Assistent unten rechts; nutzt Palette und Schriften der Vorlage (bg-t-*, font-t-*)
export function ChatWidget({ content }: { content: TemplateContent }) {
    const access = useAiAccess()
    const chat = useAiChat({ access, mode: "chat" })
    const [open, setOpen] = useState(false)
    const [teaser, setTeaser] = useState(false)
    const [draft, setDraft] = useState("")
    const listRef = useRef<HTMLDivElement>(null)
    const enabled = Boolean(access && content.ai.chat)

    const name = content.ai.name.trim() || "Assistent"
    const brand = brandName(content)
    const greeting = content.ai.greeting.trim() || `Hallo! Ich bin ${name}${brand ? ` von ${brand}` : ""}. Wie kann ich Ihnen helfen?`

    useEffect(() => {
        if (!enabled) return
        const timer = setTimeout(() => setTeaser(true), 4000)
        return () => clearTimeout(timer)
    }, [enabled])

    useEffect(() => {
        listRef.current?.scrollTo({ top: listRef.current.scrollHeight, behavior: "smooth" })
    }, [chat.messages, open])

    if (!enabled) return null

    const last = chat.messages[chat.messages.length - 1]
    const typing = chat.pending && last?.role === "assistant" && last.parts.length === 0

    function submit(text: string) {
        if (!text.trim() || chat.pending) return
        setDraft("")
        void chat.send(text)
    }

    return (
        <div className="fixed right-4 bottom-[calc(1rem+var(--t-safe-bottom,0px))] z-[70] flex flex-col items-end gap-3 font-t-body">
            <AnimatePresence>
                {open && (
                    <motion.section
                        aria-label={`Chat mit ${name}`}
                        initial={{ opacity: 0, y: 16, scale: 0.96 }}
                        animate={{ opacity: 1, y: 0, scale: 1 }}
                        exit={{ opacity: 0, y: 16, scale: 0.96 }}
                        transition={{ duration: 0.35, ease }}
                        className="flex h-[min(560px,calc(100dvh-7rem))] w-[min(380px,calc(100vw-2rem))] origin-bottom-right flex-col overflow-hidden rounded-3xl border border-t-fg/10 bg-t-bg text-t-fg shadow-[0_30px_80px_-20px_rgba(0,0,0,0.45)]"
                    >
                        <header className="flex items-center gap-3 border-b border-t-fg/10 px-4 py-3">
                            <span className="grid size-10 shrink-0 place-items-center rounded-full bg-t-accent font-semibold text-t-accent-fg">
                                {name.charAt(0).toUpperCase()}
                            </span>
                            <div className="min-w-0 flex-1">
                                <p className="truncate font-medium">{name}</p>
                                <p className="flex items-center gap-1.5 text-xs text-t-muted">
                                    <span className="size-1.5 rounded-full bg-emerald-500" /> KI-Assistent · antwortet sofort
                                </p>
                            </div>
                            <button type="button" aria-label="Chat schließen" onClick={() => setOpen(false)} className="grid size-9 cursor-pointer place-items-center rounded-full hover:bg-t-fg/5">
                                <XIcon className="size-4" />
                            </button>
                        </header>

                        <div ref={listRef} className="flex-1 space-y-3 overflow-y-auto px-4 py-4">
                            <Bubble role="assistant">{greeting}</Bubble>
                            {chat.messages.map((message, i) => (
                                <div key={i} className="space-y-2">
                                    {message.parts.map((part, j) =>
                                        part.type === "booking" ? (
                                            <BookingCard key={j} data={part.data} className="border-t-accent/40 bg-t-surface" />
                                        ) : (
                                            <Bubble key={j} role={message.role}>{part.text}</Bubble>
                                        )
                                    )}
                                </div>
                            ))}
                            {typing && (
                                <div className="flex w-fit gap-1 rounded-2xl rounded-bl-md bg-t-surface px-4 py-3">
                                    {[0, 1, 2].map((dot) => (
                                        <motion.span
                                            key={dot}
                                            className="size-1.5 rounded-full bg-t-muted"
                                            animate={{ y: [0, -4, 0] }}
                                            transition={{ duration: 0.8, repeat: Infinity, delay: dot * 0.15 }}
                                        />
                                    ))}
                                </div>
                            )}
                            {chat.error && <p className="text-sm text-red-500">{chat.error}</p>}
                            {chat.messages.length === 0 && (
                                <div className="flex flex-wrap gap-2 pt-1">
                                    {QUICK_REPLIES.map((reply) => (
                                        <button
                                            key={reply}
                                            type="button"
                                            onClick={() => submit(reply)}
                                            className="cursor-pointer rounded-full border border-t-fg/15 px-3 py-1.5 text-left text-xs transition-colors hover:border-t-accent hover:text-t-accent"
                                        >
                                            {reply}
                                        </button>
                                    ))}
                                </div>
                            )}
                        </div>

                        <form
                            className="flex items-center gap-2 border-t border-t-fg/10 p-3"
                            onSubmit={(event) => {
                                event.preventDefault()
                                submit(draft)
                            }}
                        >
                            <input
                                value={draft}
                                onChange={(event) => setDraft(event.target.value)}
                                placeholder="Nachricht schreiben …"
                                aria-label="Nachricht"
                                maxLength={1500}
                                className="min-w-0 flex-1 rounded-full bg-t-surface px-4 py-2.5 text-sm outline-none placeholder:text-t-muted focus:ring-2 focus:ring-t-accent/40"
                            />
                            <button
                                type="submit"
                                aria-label="Senden"
                                disabled={!draft.trim() || chat.pending}
                                className="grid size-10 shrink-0 cursor-pointer place-items-center rounded-full bg-t-accent text-t-accent-fg transition-opacity disabled:opacity-40"
                            >
                                <ArrowUpIcon className="size-4" />
                            </button>
                        </form>
                        <p className="pb-2 text-center text-[10px] text-t-muted">KI-Demo · Antworten können Fehler enthalten</p>
                    </motion.section>
                )}
            </AnimatePresence>

            <AnimatePresence>
                {teaser && !open && (
                    <motion.button
                        type="button"
                        initial={{ opacity: 0, y: 8 }}
                        animate={{ opacity: 1, y: 0 }}
                        exit={{ opacity: 0, y: 8 }}
                        onClick={() => setOpen(true)}
                        className="max-w-60 cursor-pointer rounded-2xl rounded-br-md bg-t-bg px-4 py-3 text-left text-sm text-t-fg shadow-xl ring-1 ring-t-fg/10"
                    >
                        Fragen? Ich antworte sofort – auch auf Terminwünsche.
                    </motion.button>
                )}
            </AnimatePresence>

            <motion.button
                type="button"
                aria-label={open ? "Chat schließen" : `Chat mit ${name} öffnen`}
                onClick={() => {
                    setOpen(!open)
                    setTeaser(false)
                }}
                whileHover={{ scale: 1.06 }}
                whileTap={{ scale: 0.94 }}
                className="grid size-14 cursor-pointer place-items-center rounded-full bg-t-accent text-t-accent-fg shadow-[0_12px_40px_-8px_var(--t-accent)]"
            >
                {open ? <XIcon className="size-5" /> : <MessageCircleIcon className="size-6" />}
            </motion.button>
        </div>
    )
}

function Bubble({ role, children }: { role: "user" | "assistant"; children: string }) {
    return (
        <p
            className={cn(
                "w-fit max-w-[85%] whitespace-pre-wrap rounded-2xl px-4 py-2.5 text-sm leading-relaxed",
                role === "user" ? "ml-auto rounded-br-md bg-t-accent text-t-accent-fg" : "rounded-bl-md bg-t-surface"
            )}
        >
            {children}
        </p>
    )
}