"use client";

import type { ElementType, ReactNode } from "react";
import ReactMarkdown, { type Components } from "react-markdown";
import rehypeKatex from "rehype-katex";
import remarkGfm from "remark-gfm";
import remarkMath from "remark-math";
import { AlertTriangle, CheckCircle2, Quote } from "lucide-react";
import { AnswerTrustFooter, EvidenceBadge } from "@/components/dashboard/EvidenceBadge";
import type { BrainAskCitation } from "@/lib/api/types";
import type { StudyIntent } from "@/lib/study-intents";
import { mapSuggestedActionToIntent } from "./study-brain-context";
import type { StudyCardMeta } from "./types";

export const markdownComponents: Components = {
  p: ({ children }) => <p className="mb-3 last:mb-0">{children}</p>,
  ul: ({ children }) => <ul className="mb-3 list-disc space-y-1 pl-5 last:mb-0">{children}</ul>,
  ol: ({ children }) => <ol className="mb-3 list-decimal space-y-1 pl-5 last:mb-0">{children}</ol>,
  li: ({ children }) => <li className="leading-6">{children}</li>,
  strong: ({ children }) => <strong className="font-semibold text-white">{children}</strong>,
  em: ({ children }) => <em className="italic">{children}</em>,
  a: ({ children, href }) => (
    <a href={href} target="_blank" rel="noreferrer noopener" className="font-semibold text-white underline underline-offset-2">
      {children}
    </a>
  ),
  code: ({ children }) => (
    <code className="rounded-md border border-white/[0.08] bg-black/30 px-1.5 py-0.5 text-[0.92em] text-white/82">
      {children}
    </code>
  ),
};

export function Prose({ children }: { children: unknown }) {
  // Defensive: AI/backend fields are sometimes numbers, arrays, or objects even
  // when typed as string. Coerce so a non-string never crashes the whole card
  // tree with "x.trim is not a function".
  const text = typeof children === "string" ? children.trim() : children == null ? "" : String(children).trim();
  if (!text) return null;
  return (
    <ReactMarkdown remarkPlugins={[remarkGfm, remarkMath]} rehypePlugins={[rehypeKatex]} components={markdownComponents}>
      {text}
    </ReactMarkdown>
  );
}

export function Section({ title, children }: { title: unknown; children: ReactNode }) {
  const safeTitle = typeof title === "string" ? title : title == null ? "" : String(title);
  return (
    <section className="rounded-2xl border border-white/[0.075] bg-white/[0.025] p-4">
      <p className="text-[11px] font-semibold uppercase text-white/40">{safeTitle}</p>
      <div className="mt-3 text-sm leading-6 text-white/74">{children}</div>
    </section>
  );
}

export function BulletList({ items, limit = 8 }: { items: ReadonlyArray<unknown>; limit?: number }) {
  // Coerce each item to a string first — backend list fields occasionally
  // contain numbers/objects, and item.trim() on those crashes the card tree.
  const clean = (items ?? [])
    .map((item) => (typeof item === "string" ? item : item == null ? "" : String(item)))
    .filter((item) => item.trim().length > 0)
    .slice(0, limit);
  if (clean.length === 0) return <p className="text-white/50">DocDoe will add this when the source has enough detail.</p>;
  return (
    <ul className="space-y-2">
      {clean.map((item, index) => (
        <li key={`${item}-${index}`} className="flex gap-2">
          <CheckCircle2 className="mt-1 size-3.5 shrink-0 text-white/48" />
          <span>{item}</span>
        </li>
      ))}
    </ul>
  );
}

export function TrustFooter({ meta }: { meta?: StudyCardMeta }) {
  if (!meta?.evidenceLabel && !meta?.trustNote && !meta?.isFallback) {
    return <AnswerTrustFooter />;
  }

  return (
    <div className="mt-4 space-y-2 rounded-2xl border border-white/[0.06] bg-black/18 p-3">
      {meta?.isFallback ? (
        <p className="flex items-start gap-2 text-xs leading-5 text-amber-100/82">
          <AlertTriangle className="mt-0.5 size-3.5 shrink-0" />
          Degraded answer — the AI pipeline used a fallback. Retry or attach a clearer source.
        </p>
      ) : null}
      {meta?.evidenceLabel ? (
        <div>
          <EvidenceBadge label={meta.evidenceLabel} />
        </div>
      ) : null}
      {meta?.trustNote ? <p className="text-xs leading-5 text-white/42">{meta.trustNote}</p> : null}
      <AnswerTrustFooter />
    </div>
  );
}

export function CitationBlock({ citations }: { citations: BrainAskCitation[] }) {
  const visible = citations.filter((citation) => citation.snippet || citation.source_title || citation.heading).slice(0, 5);
  if (visible.length === 0) return null;

  return (
    <div className="mt-4 rounded-2xl border border-white/[0.07] bg-black/20 p-4">
      <p className="text-[11px] font-semibold uppercase text-white/40">Retrieved evidence</p>
      <div className="mt-3 space-y-3">
        {visible.map((citation, index) => (
          <div key={`${citation.chunk_id ?? citation.source_title ?? index}`} className="rounded-xl border border-white/[0.06] bg-white/[0.02] p-3">
            <div className="flex gap-2 text-sm font-semibold text-white/72">
              <Quote className="mt-0.5 size-3.5 shrink-0 text-white/36" />
              <span>
                {citation.source_title ?? "Study material"}
                {citation.page_number ? ` · p.${citation.page_number}` : ""}
                {citation.heading ? ` · ${citation.heading}` : ""}
              </span>
            </div>
            {citation.snippet ? (
              <p className="mt-2 text-xs leading-5 text-white/48 line-clamp-3">{citation.snippet}</p>
            ) : null}
          </div>
        ))}
      </div>
    </div>
  );
}

export function FollowUpActions({
  topic,
  onAction,
  meta,
}: {
  topic: string;
  onAction: (intent: StudyIntent, prompt: string) => void;
  meta?: StudyCardMeta;
}) {
  const fromApi = (meta?.suggestedActions ?? [])
    .map((action) => {
      const mapped = mapSuggestedActionToIntent(action);
      if (!mapped) return null;
      return { label: action.length > 42 ? `${action.slice(0, 39)}...` : action, ...mapped };
    })
    .filter((item): item is { label: string; intent: StudyIntent; prompt: string } => Boolean(item))
    .slice(0, 4);

  const defaults: Array<{ label: string; intent: StudyIntent; prompt: string }> = [
    { label: "Explain deeper", intent: "teach_topic", prompt: `Explain ${topic} deeper with examples and exam keywords` },
    { label: "Create quiz", intent: "generate_quiz", prompt: `Quiz me on ${topic}` },
    { label: "Scoring notes", intent: "generate_notes", prompt: `Make exam-ready notes on ${topic}` },
    { label: "Video plan", intent: "create_video_plan", prompt: `Create a study video plan for ${topic}` },
  ];

  const actions = fromApi.length > 0 ? fromApi : defaults;

  return (
    <div className="mt-4 flex flex-wrap gap-2">
      {actions.map((action) => (
        <button
          key={`${action.label}-${action.intent}`}
          type="button"
          onClick={() => onAction(action.intent, action.prompt)}
          className="rounded-full border border-white/[0.09] bg-white/[0.035] px-3 py-1.5 text-xs font-semibold text-white/62 transition hover:border-white/[0.18] hover:text-white focus:outline-none focus-visible:ring-2 focus-visible:ring-white/22"
        >
          {action.label}
        </button>
      ))}
    </div>
  );
}

export function RichStudyCard({
  icon: Icon,
  title,
  eyebrow,
  children,
}: {
  icon: ElementType;
  title: string;
  eyebrow: string;
  children: ReactNode;
}) {
  return (
    <article className="animate-msg-assistant relative overflow-hidden rounded-[1.45rem] border border-[var(--kb-card-border,rgba(255,255,255,0.085))] bg-[var(--kb-card-bg,linear-gradient(145deg,rgba(255,255,255,0.052),rgba(255,255,255,0.018)))] p-5 shadow-[0_18px_70px_rgba(0,0,0,0.34),inset_0_1px_0_rgba(255,255,255,0.04)] sm:p-6">
      <div className="mb-4 flex items-start gap-3">
        <span className="grid size-10 shrink-0 place-items-center rounded-2xl border border-white/[0.09] bg-white/[0.04] text-white/76">
          <Icon className="size-5" />
        </span>
        <div className="min-w-0">
          <p className="text-[11px] font-semibold uppercase text-white/38">{eyebrow}</p>
          <h2 className="mt-1 text-lg font-semibold text-white sm:text-xl">{title}</h2>
        </div>
      </div>
      {children}
    </article>
  );
}