import config from "@payload-config";
import { getPayload } from "payload";
import { headers as nextHeaders } from "next/headers";
import { RichText } from "@payloadcms/richtext-lexical/react";
import type { StoryBeat, StoryBeatState } from "@/payload-types";
import { isPayloadUser } from "@/utils/access-control/isPayloadUser";
import { cn } from "@/lib/utils";
import { BEAT_BODY_CLASSES } from "@/lib/story/richtextClasses";
import { BeatReactions } from "@/components/frontend/story/BeatReactions";
import { BeatReadMarker } from "@/components/frontend/story/BeatReadMarker";
import { StoryViewer, type StoryViewerBeat } from "@/components/frontend/story/StoryViewer";
import type { StoryReaction } from "@/lib/story/reactions";

export const metadata = {
  title: "Chronicle",
};

type ReactionCounts = Record<StoryReaction, number>;

const DATE_FORMAT = new Intl.DateTimeFormat("en-US", {
  year: "numeric",
  month: "long",
  day: "numeric",
});

function emptyCounts(): ReactionCounts {
  return { like: 0, heart: 0, salute: 0 };
}

function sortBeats(beats: StoryBeat[]): StoryBeat[] {
  return [...beats].sort((a, b) => {
    const timeA = a.occurredAt ? Date.parse(a.occurredAt) : Number.POSITIVE_INFINITY;
    const timeB = b.occurredAt ? Date.parse(b.occurredAt) : Number.POSITIVE_INFINITY;
    if (timeA !== timeB) return timeA - timeB;
    const orderA = a.order ?? Number.POSITIVE_INFINITY;
    const orderB = b.order ?? Number.POSITIVE_INFINITY;
    if (orderA !== orderB) return orderA - orderB;
    return Date.parse(a.createdAt) - Date.parse(b.createdAt);
  });
}

export default async function StoryPage() {
  const payloadConfig = await config;
  const payload = await getPayload({ config: payloadConfig });
  const headers = await nextHeaders();
  const { user } = await payload.auth({ headers, canSetHeaders: false });

  if (!isPayloadUser(user)) return null;

  const beatsResult = await payload.find({
    collection: "story-beats",
    where: { status: { equals: "published" } },
    limit: 200,
    depth: 1,
    overrideAccess: false,
    user,
  });
  const sorted = sortBeats(beatsResult.docs as StoryBeat[]);

  const statesResult = await payload.find({
    collection: "story-beat-states",
    where: { user: { equals: user.id } },
    limit: 500,
    depth: 0,
    overrideAccess: false,
    user,
  });
  const stateByBeat = new Map<number, StoryBeatState>();
  for (const state of statesResult.docs as StoryBeatState[]) {
    const beatId = typeof state.beat === "number" ? state.beat : state.beat.id;
    stateByBeat.set(beatId, state);
  }

  const beatIds = sorted.map((beat) => beat.id);
  const counts = new Map<number, ReactionCounts>();
  for (const id of beatIds) counts.set(id, emptyCounts());
  if (beatIds.length > 0) {
    const reactionDocs = await payload.find({
      collection: "story-beat-states",
      where: {
        and: [{ beat: { in: beatIds } }, { reaction: { not_equals: null } }],
      },
      limit: 1000,
      depth: 0,
      overrideAccess: true,
    });
    for (const doc of reactionDocs.docs as StoryBeatState[]) {
      const beatId = typeof doc.beat === "number" ? doc.beat : doc.beat.id;
      const beatCounts = counts.get(beatId);
      if (doc.reaction && beatCounts) beatCounts[doc.reaction] += 1;
    }
  }

  const readerBeats: StoryViewerBeat[] = sorted.map((beat, index) => ({
    id: beat.id,
    title: beat.title,
    chapter: index + 1,
    dateLabel: beat.occurredAt ? DATE_FORMAT.format(new Date(beat.occurredAt)) : null,
    body: beat.body,
    initialRead: Boolean(stateByBeat.get(beat.id)?.readAt),
  }));

  return (
    <div className="mx-auto max-w-3xl px-4 py-10">
      <header className="mb-12 text-center">
        <p className="text-xs uppercase tracking-[0.3em] text-muted-foreground">
          The Unit Chronicle
        </p>
        <h1 className="mt-2 font-serif text-4xl font-bold">Story Chronicle</h1>
        <p className="mt-3 text-muted-foreground">
          Every operation leaves a mark. These are the beats of our story, told in
          order.
        </p>
        {sorted.length > 0 && (
          <div className="mt-5 flex justify-center">
            <StoryViewer beats={readerBeats} />
          </div>
        )}
      </header>

      {sorted.length === 0 ? (
        <p className="text-center text-muted-foreground">
          No published chapters yet. Check back soon.
        </p>
      ) : (
        <ol className="space-y-16">
          {sorted.map((beat, index) => {
            const state = stateByBeat.get(beat.id);
            const mission =
              beat.mission && typeof beat.mission !== "number" ? beat.mission : null;
            const missionLabel = mission
              ? mission.codeName
                ? `${mission.codeName} · ${mission.name}`
                : mission.name
              : null;
            return (
              <li
                key={beat.id}
                data-beat-id={beat.id}
                className="relative border-l border-border pl-8"
              >
                <span className="absolute -left-[9px] top-1.5 size-4 rounded-full border-2 border-background bg-primary" />
                <div className="flex items-center justify-between gap-4">
                  <p className="text-xs uppercase tracking-widest text-muted-foreground">
                    Chapter {index + 1}
                  </p>
                  <BeatReadMarker beatId={beat.id} initialRead={Boolean(state?.readAt)} />
                </div>
                <h2 className="mt-2 font-serif text-2xl font-semibold">{beat.title}</h2>
                <div className="mt-1 flex flex-wrap items-center gap-3 text-xs text-muted-foreground">
                  {beat.occurredAt && <span>{DATE_FORMAT.format(new Date(beat.occurredAt))}</span>}
                  {missionLabel && (
                    <span className="rounded border border-border px-2 py-0.5">
                      {missionLabel}
                    </span>
                  )}
                </div>
                <div className="mt-4">
                  <RichText data={beat.body} className={cn(BEAT_BODY_CLASSES)} />
                </div>
                <BeatReactions
                  beatId={beat.id}
                  initialReaction={state?.reaction ?? null}
                  initialCounts={counts.get(beat.id) ?? emptyCounts()}
                />
              </li>
            );
          })}
        </ol>
      )}
    </div>
  );
}