"use client";

import { useEffect, useRef } from "react";

import { AiDisclaimer } from "@/components/AiDisclaimer";
import { ChatIcon, LayersIcon, PaperclipIcon, SendIcon, StopIcon, XIcon } from "@/components/icons";
import { Spinner } from "@/components/ui";
import { useI18n } from "@/lib/i18n";
import { useIsPhone } from "@/lib/use-phone";
import type { ChatAttachment } from "@/lib/chat";
import { cn } from "@/lib/utils";

export type PendingAttachment = { attachment: ChatAttachment; text: string };

/**
 * The pinned composer: auto-growing 16px textarea, send/stop, attach, and the
 * context + model chips. Enter sends on desktop, newline on phones; the
 * keyboard inset is handled by the screen around it.
 */
export function Composer({
  value,
  onChange,
  onSend,
  onStop,
  busy,
  online,
  scopeLabel,
  modelLabel,
  scopeOpen,
  modelOpen,
  onOpenScope,
  onOpenModel,
  onAttachFile,
  attachBusy,
  attachments,
  onRemoveAttachment,
}: {
  value: string;
  onChange: (value: string) => void;
  onSend: () => void;
  onStop: () => void;
  busy: boolean;
  online: boolean;
  scopeLabel: string;
  modelLabel: string;
  scopeOpen: boolean;
  modelOpen: boolean;
  onOpenScope: () => void;
  onOpenModel: () => void;
  onAttachFile: (file: File) => void;
  attachBusy: boolean;
  attachments: PendingAttachment[];
  onRemoveAttachment: (index: number) => void;
}) {
  const { t } = useI18n();
  const isPhone = useIsPhone();
  const textarea = useRef<HTMLTextAreaElement>(null);
  const fileInput = useRef<HTMLInputElement>(null);

  useEffect(() => {
    const element = textarea.current;
    if (!element) return;
    element.style.height = "auto";
    element.style.height = `${Math.min(element.scrollHeight, 180)}px`;
  }, [value]);

  const canSend = online && !busy && value.trim().length > 0;

  return (
    <div className="border-t border-[var(--glass-border)] bg-[var(--glass-bg)] px-3 pb-safe pt-2 backdrop-blur-xl">
      {attachments.length > 0 ? (
        <ul className="mb-2 flex flex-wrap gap-1.5">
          {attachments.map((entry, index) => (
            <li
              key={`${entry.attachment.name}-${index}`}
              className="flex items-center gap-1.5 rounded-xl border border-[var(--hairline-soft)] bg-[var(--surface-sunken)] py-1 pl-2.5 pr-1 text-[12px] text-[var(--text-muted)]"
            >
              <span className="max-w-[160px] truncate">{entry.attachment.name}</span>
              <span className="text-[var(--text-subtle)]">{entry.attachment.kind === "photo" ? t("chat.attachPhoto") : t("chat.attachDoc")}</span>
              <button
                type="button"
                aria-label={t("chat.attachRemove")}
                title={t("chat.attachRemove")}
                onClick={() => onRemoveAttachment(index)}
                className="grid size-6 place-items-center rounded-lg text-[var(--text-subtle)] transition hover:bg-[var(--hover)] hover:text-[var(--text)]"
              >
                <XIcon className="size-3.5" />
              </button>
            </li>
          ))}
        </ul>
      ) : null}

      <div className="flex items-end gap-2">
        <button
          type="button"
          aria-label={t("chat.attach")}
          title={t("chat.attach")}
          disabled={attachBusy}
          onClick={() => fileInput.current?.click()}
          className="grid size-10 shrink-0 place-items-center rounded-2xl border border-[var(--glass-border)] bg-[var(--surface-strong)] text-[var(--text-muted)] transition hover:bg-[var(--hover)] hover:text-[var(--text)] disabled:opacity-60"
        >
          {attachBusy ? <Spinner className="size-4" /> : <PaperclipIcon className="size-5" />}
        </button>
        <input
          ref={fileInput}
          type="file"
          accept="image/*,application/pdf,.docx,.pptx,.odt,.txt,.md,.csv"
          className="sr-only"
          onChange={(event) => {
            const file = event.target.files?.[0];
            if (file) onAttachFile(file);
            event.target.value = "";
          }}
        />

        <textarea
          ref={textarea}
          value={value}
          onChange={(event) => onChange(event.target.value)}
          onKeyDown={(event) => {
            if (event.key !== "Enter" || event.shiftKey || isPhone) return;
            if (event.nativeEvent.isComposing) return;
            event.preventDefault();
            if (canSend) onSend();
          }}
          rows={1}
          placeholder={t("chat.placeholder")}
          aria-label={t("chat.placeholder")}
          className="max-h-[180px] min-h-[44px] min-w-0 flex-1 resize-none rounded-2xl border border-[var(--glass-border)] bg-[var(--surface-strong)] px-3.5 py-2.5 text-[16px] leading-relaxed text-[var(--text)] outline-none transition-[height,border-color] duration-150 ease-out placeholder:text-[var(--text-subtle)] focus:border-accent-400/60 motion-reduce:transition-none"
        />

        {busy ? (
          <button
            type="button"
            onClick={onStop}
            aria-label={t("chat.stop")}
            title={t("chat.stop")}
            className="grid size-10 shrink-0 place-items-center rounded-2xl border border-[var(--glass-border)] bg-[var(--surface-strong)] text-[var(--text)] transition hover:bg-[var(--hover)]"
          >
            <StopIcon className="size-5" />
          </button>
        ) : (
          <button
            type="button"
            onClick={onSend}
            disabled={!canSend}
            aria-label={t("chat.send")}
            title={t("chat.send")}
            className={cn(
              "grid size-10 shrink-0 place-items-center rounded-2xl transition",
              canSend ? "grad-ice text-[#06111f]" : "border border-[var(--glass-border)] bg-[var(--surface-strong)] text-[var(--text-subtle)] opacity-60",
            )}
          >
            <SendIcon className="size-5" />
          </button>
        )}
      </div>

      <div className="mt-2 flex items-center gap-2 overflow-x-auto">
        <button
          type="button"
          data-picker-trigger
          aria-haspopup="dialog"
          aria-expanded={scopeOpen}
          onClick={onOpenScope}
          className={pickerChipClass(scopeOpen)}
        >
          <LayersIcon className="size-3.5 shrink-0" />
          <span className="max-w-[170px] truncate">{scopeLabel}</span>
        </button>
        <button
          type="button"
          data-picker-trigger
          aria-haspopup="dialog"
          aria-expanded={modelOpen}
          onClick={onOpenModel}
          className={pickerChipClass(modelOpen)}
        >
          <ChatIcon className="size-3.5 shrink-0" />
          <span className="max-w-[170px] truncate">{modelLabel}</span>
        </button>
        {!online ? (
          <span role="status" className="ml-auto shrink-0 text-[11.5px] text-amber-600 dark:text-amber-300">
            {t("chat.offlineNote")}
          </span>
        ) : null}
      </div>

      <AiDisclaimer className="mt-1.5" />
    </div>
  );
}

/**
 * Chip style for the two popover triggers (context, model). The open state
 * reads pressed, because the same chip opens and closes its popover.
 */
function pickerChipClass(open: boolean): string {
  return cn(
    "flex min-w-0 items-center gap-1.5 rounded-xl border px-2.5 py-1.5 text-[12px] font-medium transition",
    open
      ? "border-[var(--nav-active-border)] bg-[var(--nav-active-bg)] text-[var(--text)]"
      : "border-[var(--hairline-soft)] bg-[var(--surface-sunken)] text-[var(--text-muted)] hover:text-[var(--text)]",
  );
}