electric-cherry/src/lib/server/moderation/evidence.ts

import { db } from '../db/index.js';
import { AuthError } from '../auth/index.js';
import { matchChatTimeline } from '../fleet/chat.js';
import { moderationGuid, type ModerationGame } from '../../moderation.js';
import type { ContextualChatEntry } from '../../game-chat.js';
import { textField } from './core.js';

type Message = Extract<ContextualChatEntry, { type: 'message' }>;

/** Verify against the archive, then preserve independent excerpts across all participants. */
export function archivedEvidenceSnapshots(
    caseId: string,
    target: { game: ModerationGame; guid: string },
    value: unknown
) {
    const requested = value as Record<string, unknown> | null;
    if (!requested || !Number.isSafeInteger(requested.matchId))
        throw new AuthError('Choose a recorded chat message.');
    const matchId = requested.matchId as number;
    const match = db()
        .prepare('SELECT game,server,started_at FROM leaderboard_matches WHERE id=?')
        .get(matchId) as { game: string; server: string; started_at: string } | undefined;
    if (!match || match.game !== target.game)
        throw new AuthError('The source match is unavailable.', 404);
    const entries = matchChatTimeline(matchId).filter(
        (entry): entry is Message => entry.type === 'message'
    );
    const byId = new Map(entries.map((entry) => [entry.messageId!, entry]));
    const isSubject = (entry: Message) =>
        moderationGuid(target.game, entry.message.guid) === target.guid;
    const legacy = requested.messageIds === undefined;
    let selected: Message[];
    if (legacy) {
        textField(requested.message, 'Chat message', 4096);
        selected = entries.filter(
            (entry) => isSubject(entry) && entry.message.message === requested.message
        );
    } else {
        if (
            !Array.isArray(requested.messageIds) ||
            !requested.messageIds.length ||
            requested.messageIds.length > 100 ||
            requested.messageIds.some((id) => typeof id !== 'string' || !byId.has(id))
        )
            throw new AuthError('Select between 1 and 100 archived message identifiers.');
        const ids = new Set(requested.messageIds);
        selected = entries.filter((entry) => ids.has(entry.messageId));
    }
    if (!selected.length || !selected.some(isSubject))
        throw new AuthError(
            'The original chat message could not be verified in the archive. Select a message from the case subject.',
            409
        );
    const radius = (key: string) => {
        const count = requested[key] ?? 3;
        if (!Number.isSafeInteger(count) || (count as number) < 0 || (count as number) > 20)
            throw new AuthError('Choose between 0 and 20 surrounding messages.');
        return count as number;
    };
    const before = radius('contextBefore'),
        after = radius('contextAfter');
    const attached = new Set<string>();
    const prior = db()
        .prepare(
            'SELECT snapshot FROM moderation_evidence WHERE case_id=? AND snapshot IS NOT NULL'
        )
        .all(caseId) as { snapshot: string }[];
    for (const row of prior) {
        try {
            const snapshot = JSON.parse(row.snapshot);
            if (snapshot.matchId !== matchId) continue;
            if (Array.isArray(snapshot.selectedMessageIds)) {
                for (const id of snapshot.selectedMessageIds)
                    if (typeof id === 'string') attached.add(id);
            } else if (snapshot.entry?.type === 'message') {
                // Older evidence predates IDs. Match each occurrence once without changing history.
                const old = snapshot.entry.message;
                const original = entries.find(
                    (entry) =>
                        !attached.has(entry.messageId!) &&
                        entry.message.guid === old.guid &&
                        entry.message.time === old.time &&
                        entry.message.player === old.player &&
                        entry.message.channel === old.channel &&
                        entry.message.message === old.message
                );
                if (original) attached.add(original.messageId!);
            }
        } catch {
            /* Keep malformed legacy snapshots readable without trusting them as identities. */
        }
    }
    const fresh = selected.filter((entry) => !attached.has(entry.messageId!));
    if (!fresh.length) return [];
    // Keep the original selected subject as context when only a newly selected reply is fresh.
    const groups = legacy ? fresh.map((entry) => [entry]) : [selected];
    return groups.map((group) => {
        const indexes = new Set<number>();
        for (const entry of group) {
            const index = entries.indexOf(entry);
            for (
                let i = Math.max(0, index - before);
                i <= Math.min(entries.length - 1, index + after);
                i++
            )
                indexes.add(i);
        }
        const primary = group.find(isSubject)!;
        return {
            text: group
                .filter(isSubject)
                .map((entry) => entry.message.message)
                .join('\n'),
            source: `Archived chat · ${match.server} · match ${matchId}`,
            snapshot: JSON.stringify({
                version: 2,
                matchId,
                match,
                entry: primary,
                entries: [...indexes].sort((a, b) => a - b).map((index) => entries[index]),
                selectedMessageIds: group
                    .filter((entry) => !attached.has(entry.messageId!))
                    .map((entry) => entry.messageId),
                highlightedMessageIds: group.filter(isSubject).map((entry) => entry.messageId)
            })
        };
    });
}