import { db } from '../db/index.js';
import { enrichGameChatTimeline, type ChatMatch, type ChatRoundReport, type ContextualChatEntry } from '../../game-chat.js';
import { parseGameEvent } from '../../telemetry.js';
import { TELEMETRY_REQUEST_RETENTION } from '../../telemetry-diagnostics.js';
import type { ServerRow } from './servers.js';
import type { TailResult } from './logs.js';

/** Historical context is scoped to this registration, including round-one matches. */
export function serverChatTimeline(server: ServerRow, tail: TailResult): ContextualChatEntry[] {
    const handle = db();
    const matches = handle.prepare(`SELECT started_at AS startedAt, ended_at AS endedAt,
        last_received_at AS lastReceivedAt, status, start_observed AS startObserved
        FROM leaderboard_matches WHERE server = ? AND server_deleted_at IS NULL
        ORDER BY id DESC LIMIT 2000`).all(server.name) as Array<Omit<ChatMatch, 'startObserved'> & { startObserved: number }>;

    // Diagnostic history survives deletion. Its receipt time must belong to the
    // current registration so a reused server name cannot inherit old rounds.
    const cutoff = new Date(Date.now() - TELEMETRY_REQUEST_RETENTION.maxAgeDays * 86_400_000).toISOString();
    const reports = handle.prepare(`SELECT received_at AS receivedAt, event, round,
        player_count AS playerCount FROM telemetry_requests
        WHERE server = ? AND status = 200 AND received_at >= ?
            AND julianday(received_at) >= julianday(?)
            AND event IN ('game_start', 'round_change', 'heartbeat', 'game_end')
            AND player_count >= 0 AND (event = 'game_start' OR round >= 0)
        ORDER BY id DESC LIMIT ?`).all(server.name, cutoff, server.created_at,
            TELEMETRY_REQUEST_RETENTION.maxPerServer) as ChatRoundReport[];

    // Saving gameplay does not depend on diagnostic logging succeeding. Keep the
    // surviving accepted snapshot useful when its request log was not recorded.
    const latest = handle.prepare(`SELECT received_at AS receivedAt, payload FROM server_telemetry
        WHERE server = ? AND received_at >= ? AND julianday(received_at) >= julianday(?)`)
        .get(server.name, cutoff, server.created_at) as { receivedAt: string; payload: string | null } | undefined;
    if (latest?.payload) {
        try {
            const event = parseGameEvent(JSON.parse(latest.payload));
            const round = event.event === 'game_start' ? null : event.round;
            if (event.server === server.name && !reports.some(report => report.receivedAt === latest.receivedAt
                && report.event === event.event && report.round === round && report.playerCount === event.players.length)) {
                reports.push({ receivedAt: latest.receivedAt, event: event.event, round, playerCount: event.players.length });
            }
        } catch { /* Legacy malformed snapshots cannot establish chat context. */ }
    }

    return enrichGameChatTimeline(tail.lines, {
        mtime: tail.mtime,
        matches: matches.map(match => ({ ...match, startObserved: Boolean(match.startObserved) })),
        reports
    });
}