import { useEffect, useRef, useState } from "react";
import { Button } from "./primitives";
import { Icon } from "./Icon";

export interface ChatInputProps {
  onSend: (text: string, image?: string) => void;
  sending: boolean;
  onVoice: () => void;
  placeholder?: string;
}

export function ChatInput({
  onSend,
  sending,
  onVoice,
  placeholder = "给昔涟发消息…",
}: ChatInputProps): React.ReactNode {
  const [value, setValue] = useState("");
  const [pendingImage, setPendingImage] = useState<string | undefined>(undefined);
  const taRef = useRef<HTMLTextAreaElement>(null);
  const fileRef = useRef<HTMLInputElement>(null);

  // auto-grow the textarea up to a max height
  useEffect(() => {
    const el = taRef.current;
    if (!el) return;
    el.style.height = "auto";
    el.style.height = Math.min(el.scrollHeight, 140) + "px";
  }, [value]);

  const onPickFile = (e: React.ChangeEvent<HTMLInputElement>) => {
    const f = e.target.files?.[0];
    if (!f) return;
    const reader = new FileReader();
    reader.onload = () => {
      if (typeof reader.result === "string") setPendingImage(reader.result);
    };
    reader.readAsDataURL(f);
    e.target.value = "";
  };

  const canSend = value.trim().length > 0 || Boolean(pendingImage);

  const submit = () => {
    if (sending || !canSend) return;
    onSend(value.trim(), pendingImage);
    setValue("");
    setPendingImage(undefined);
  };

  return (
    <div className="glass sticky bottom-0 border-t border-[var(--mu-glass-border)] p-3 md:p-4">
      <div className="mx-auto flex max-w-2xl flex-col gap-2">
        {pendingImage ? (
          <div className="relative inline-flex w-fit overflow-hidden rounded-[var(--mu-radius)] border border-[var(--mu-glass-border)]">
            <img
              src={pendingImage}
              alt="待发送图片"
              className="h-20 w-20 object-cover"
            />
            <button
              onClick={() => setPendingImage(undefined)}
              aria-label="移除图片"
              className="absolute right-1 top-1 inline-flex h-5 w-5 items-center justify-center rounded-full bg-[var(--mu-surface-4)]/90 text-[var(--mu-text-hi)] transition-transform duration-200 hover:scale-110"
            >
              <Icon name="close" size={12} />
            </button>
          </div>
        ) : null}
        <div className="flex items-end gap-2 rounded-[var(--mu-radius-lg)] bg-[var(--mu-surface-2)] p-2 shadow-[var(--mu-shadow-1)]">
          <input
            ref={fileRef}
            type="file"
            accept="image/*"
            className="hidden"
            onChange={onPickFile}
          />
          <button
            onClick={() => fileRef.current?.click()}
            aria-label="发送图片"
            title="发送图片"
            className="inline-flex h-9 w-9 shrink-0 items-center justify-center rounded-[var(--mu-radius)] bg-[var(--mu-surface-4)] text-base transition-all duration-200 ease-[var(--mu-spring)] hover:bg-[var(--mu-surface-5)] active:scale-95"
          >
            <Icon name="image" size={18} />
          </button>
          <textarea
            ref={taRef}
            value={value}
            onChange={(e) => setValue(e.target.value)}
            onKeyDown={(e) => {
              if (e.key === "Enter" && !e.shiftKey) {
                e.preventDefault();
                submit();
              }
            }}
            rows={1}
            placeholder={placeholder}
            className="max-h-[140px] flex-1 resize-none bg-transparent px-2 py-2 text-sm text-[var(--mu-text-hi)] outline-none placeholder:text-[var(--mu-text-lo)]"
          />
          <button
            onClick={onVoice}
            aria-label="语音"
            title="发起语音通话"
            className="inline-flex h-9 w-9 shrink-0 items-center justify-center rounded-[var(--mu-radius)] bg-[var(--mu-surface-4)] text-base transition-all duration-200 ease-[var(--mu-spring)] hover:bg-[var(--mu-surface-5)] active:scale-95"
          >
            <Icon name="mic" size={18} />
          </button>
          <Button
            variant="primary"
            onClick={submit}
            disabled={sending || !canSend}
            className="shrink-0"
          >
            {sending ? "发送中…" : "发送"}
          </Button>
        </div>
      </div>
    </div>
  );
}