"use client";

import Link from "next/link";
import { memo } from "react";

import { CopyIconButton } from "./CopyIconButton";
import { Markdown } from "./Markdown";
import { ThinkingRow } from "./ThinkingRow";
import { Button } from "@/components/ui";
import { ModelErrorActions } from "@/components/ModelErrorActions";
import { PencilIcon, PlusIcon, RefreshIcon, SparklesIcon } from "@/components/icons";
import { useI18n } from "@/lib/i18n";
import type { ChatMessage } from "@/lib/chat";

/**
 * One turn: user bubbles on the right, assistant answers as full-width text
 * (no bubble) with the Thinking row, sources, actions and error recovery.
 */
export const MessageRow = memo(function MessageRow({
  message,
  streaming,
  isLastAssistant,
  isLastUser,
  busy,
  onRegenerate,
  onEdit,
  onRetry,
  onToFlashcards,
  onSaveNotes,
}: {
  message: ChatMessage;
  streaming?: boolean;
  isLastAssistant?: boolean;
  isLastUser?: boolean;
  busy?: boolean;
  onRegenerate?: () => void;
  onEdit?: () => void;
  onRetry?: () => void;
  onToFlashcards?: (message: ChatMessage) => void;
  onSaveNotes?: (message: ChatMessage) => void;
}) {
  const { t } = useI18n();

  if (message.role === "user") {
    return (
      <div className="flex flex-col items-end gap-1">
        <div className="chat-bubble max-w-[88%] rounded-[var(--radius-panel)] rounded-br-[var(--radius-chip)] border border-[var(--glass-border)] bg-[var(--surface-strong)] px-3.5 py-2.5">
          <p className="whitespace-pre-wrap break-words text-[15px] leading-relaxed text-[var(--text)]">{message.content}</p>
          {message.attachments && message.attachments.length > 0 ? (
            <p className="mt-1.5 text-[11.5px] text-[var(--text-subtle)]">
              {message.attachments.map((attachment) => attachment.name).join(" · ")}
            </p>
          ) : null}
        </div>
        {isLastUser && !busy && onEdit ? (
          <button
            type="button"
            onClick={onEdit}
            title={t("chat.edit")}
            className="flex items-center gap-1 rounded-[var(--radius-chip)] px-1.5 py-1 text-[11.5px] text-[var(--text-subtle)] transition hover:text-[var(--text)]"
          >
            <PencilIcon className="size-3.5" />
            {t("chat.edit")}
          </button>
        ) : null}
      </div>
    );
  }

  return (
    <div className="space-y-2">
      {message.thinking ? <ThinkingRow thinking={message.thinking} streaming={streaming && !message.content} /> : null}
      {message.content ? (
        <div className="chat-answer">
          <Markdown text={message.content} />
        </div>
      ) : streaming ? (
        <span className="flex items-center gap-1 py-1" role="status" aria-label={t("chat.thinking")}>
          {[0, 1, 2].map((dot) => (
            <span
              key={dot}
              className="size-1.5 animate-bounce rounded-full bg-[var(--text-subtle)] motion-reduce:animate-none motion-reduce:opacity-60"
              style={{ animationDelay: `${dot * 120}ms` }}
            />
          ))}
        </span>
      ) : null}

      {message.error ? (
        <div
          role="alert"
          className="rounded-[var(--radius-control)] border border-rose-300/60 bg-rose-50/70 p-3 dark:border-rose-400/30 dark:bg-rose-500/10"
        >
          <p className="text-[13px] leading-relaxed text-rose-800 dark:text-rose-200">{message.error.message}</p>
          <div className="mt-2 flex flex-wrap items-center gap-2">
            {onRetry ? (
              <Button size="sm" variant="secondary" onClick={onRetry}>
                <RefreshIcon className="size-4" /> {t("chat.retry")}
              </Button>
            ) : null}
            <ModelErrorActions kind={message.error.kind} />
          </div>
        </div>
      ) : null}

      {!streaming && message.content && !message.error ? (
        <div className="flex flex-wrap items-center gap-2">
          <CopyIconButton text={message.content} />
          {isLastAssistant && !busy && onRegenerate ? (
            <button
              type="button"
              onClick={onRegenerate}
              className="flex items-center gap-1.5 rounded-[var(--radius-chip)] border border-[var(--glass-border)] bg-[var(--surface-strong)] px-2.5 py-2 text-[12px] font-medium text-[var(--text)] transition hover:bg-[var(--hover)]"
            >
              <RefreshIcon className="size-3.5" />
              {t("chat.regenerate")}
            </button>
          ) : null}
          {onToFlashcards ? (
            <button
              type="button"
              onClick={() => onToFlashcards(message)}
              className="flex items-center gap-1.5 rounded-[var(--radius-chip)] border border-[var(--glass-border)] bg-[var(--surface-strong)] px-2.5 py-2 text-[12px] font-medium text-[var(--text)] transition hover:bg-[var(--hover)]"
            >
              <SparklesIcon className="size-3.5" />
              {t("chat.toFlashcards")}
            </button>
          ) : null}
          {onSaveNotes ? (
            <button
              type="button"
              onClick={() => onSaveNotes(message)}
              className="flex items-center gap-1.5 rounded-[var(--radius-chip)] border border-[var(--glass-border)] bg-[var(--surface-strong)] px-2.5 py-2 text-[12px] font-medium text-[var(--text)] transition hover:bg-[var(--hover)]"
            >
              <PlusIcon className="size-3.5" />
              {t("chat.saveToNotes")}
            </button>
          ) : null}
          {message.model ? <span className="text-[11px] text-[var(--text-subtle)]">{message.model}</span> : null}
        </div>
      ) : null}

      {message.sources && message.sources.length > 0 && !streaming ? (
        <div className="flex flex-wrap items-center gap-1.5">
          <span className="text-[11px] uppercase tracking-wide text-[var(--text-subtle)]">{t("chat.sources")}</span>
          {message.sources.slice(0, 5).map((source, index) => (
            <Link
              key={`${source.deckId}-${source.section}-${index}`}
              href={`/deck/${source.deckId}`}
              className="max-w-[220px] truncate rounded-[var(--radius-chip)] border border-[var(--glass-border)] bg-[var(--surface-strong)] px-2 py-1 text-[11.5px] text-[var(--text-muted)] transition hover:text-[var(--text)]"
              title={`${source.deckTitle} — ${source.section}`}
            >
              {source.deckTitle} · {source.section}
            </Link>
          ))}
        </div>
      ) : null}
    </div>
  );
});