Add communityStats to CommunityAssociatedAccount resolver

[kewitz]

Relates to opencollective/opencollective#8333

[gustavlrsn]

Maybe we could use a new type like CommunityAssociatedAccountTransactionSummary with just the fields we want here, to avoid confusion with CommunityTransactionSummary as the implementation is different not having year and expenseTotalAcc etc.

[gustavlrsn]

Not sure if this is a blocker or it is desired, but we have some hosts that have switched currency in their past (see query below), so this would filter the transactions before the switch.

There's a sumTransactionsInCurrency that could help to sum up the different currencies if we want to implement that, although with the drawback that the fx rate would keep changing..

WITH host_tx AS (
  SELECT
    t."HostCollectiveId",
    t."hostCurrency",
    MIN(t."createdAt") AS first_seen_at,
    MAX(t."createdAt") AS last_seen_at,
    COUNT(*)           AS tx_count
  FROM "Transactions" t
  WHERE t."deletedAt" IS NULL
    AND t."RefundTransactionId" IS NULL
    AND t."isRefund" = FALSE
    AND t."hostCurrency" IS NOT NULL
  GROUP BY t."HostCollectiveId", t."hostCurrency"
),
host_switch AS (
  SELECT
    "HostCollectiveId",
    COUNT(*) AS distinct_host_currencies,
    MIN(first_seen_at) AS first_tx_at,
    MAX(last_seen_at)  AS last_tx_at
  FROM host_tx
  GROUP BY "HostCollectiveId"
  HAVING COUNT(*) >= 2
)
SELECT
  hs."HostCollectiveId",
  h.slug        AS host_slug,
  h.name        AS host_name,
  h.currency    AS current_host_currency,
  hs.distinct_host_currencies,
  hs.first_tx_at,
  hs.last_tx_at,
  JSONB_AGG(
    JSONB_BUILD_OBJECT(
      'hostCurrency', ht."hostCurrency",
      'firstSeenAt',  ht.first_seen_at,
      'lastSeenAt',   ht.last_seen_at,
      'txCount',      ht.tx_count
    )
    ORDER BY ht.first_seen_at
  ) AS currencies_timeline
FROM host_switch hs
JOIN "Collectives" h ON h.id = hs."HostCollectiveId"
JOIN host_tx ht      ON ht."HostCollectiveId" = hs."HostCollectiveId"
GROUP BY hs."HostCollectiveId", h.slug, h.name, h.currency, hs.distinct_host_currencies, hs.first_tx_at, hs.last_tx_at
ORDER BY hs.last_tx_at DESC;

[kewitz]

I'm OK with keeping this way, because we usually have a transaction to represent the conversion from one currency to another.

This will need to change whenever we implement multi-currency hosts, but even in that condition I think I would rather display the separate amounts in each currency.