import { and, eq, isNull, sql } from 'drizzle-orm';
import { getDb, schema } from '../db/index.js';
import { generateSnowflake } from './snowflake.js';

/**
 * Opens a session when someone joins a voice room.
 *
 * Never throws: statistics must not be able to break a call. Closes any
 * dangling session for the same user first — the one-room-per-user invariant
 * means a second open row would be a bookkeeping error, not two real calls.
 */
export function openVoiceSession(input: {
  spaceId: string | null;
  channelId: string;
  userId: string;
}): void {
  try {
    const db = getDb();
    closeVoiceSession(input.userId);
    db.insert(schema.voiceSessions).values({
      id: generateSnowflake(),
      spaceId: input.spaceId,
      channelId: input.channelId,
      userId: input.userId,
      startedAt: Date.now(),
      endedAt: null,
    }).run();
  } catch (err) {
    console.warn('[voice-sessions] failed to open session', err);
  }
}

/** Closes the user's open session, if any. Never throws. */
export function closeVoiceSession(userId: string): void {
  try {
    getDb().update(schema.voiceSessions)
      .set({ endedAt: Date.now() })
      .where(and(eq(schema.voiceSessions.userId, userId), isNull(schema.voiceSessions.endedAt)))
      .run();
  } catch (err) {
    console.warn('[voice-sessions] failed to close session', err);
  }
}

/**
 * Closes sessions left open by a crash or restart.
 *
 * Their real end time is unknowable. Ending them at `startedAt` — a zero-length
 * session — discards that time rather than inventing it: crediting the gap
 * would silently hand someone hours they never spent, and the numbers are the
 * entire point of keeping this table.
 */
export function closeOrphanedVoiceSessions(): void {
  try {
    const result = getDb().update(schema.voiceSessions)
      .set({ endedAt: sql`${schema.voiceSessions.startedAt}` })
      .where(isNull(schema.voiceSessions.endedAt))
      .run();
    if (result.changes > 0) {
      console.log(`[voice-sessions] closed ${result.changes} session(s) orphaned by a restart`);
    }
  } catch (err) {
    console.warn('[voice-sessions] failed to close orphans', err);
  }
}