-- ============================================================================
-- 03_min_pool_cost_share_by_pool_size.sql
-- Q: What does the 170 ADA minPoolCost represent as a share of gross reward
--    for a pool minting 1, 2, 5 or 20 blocks in an epoch?
--
-- METHOD: gross reward per block is recomputed inline from the same definition
--   as 02_ (leader+member rewards / pool-minted blocks, epochs 641-650) so this
--   file is runnable standalone and cannot drift from 02_. The mean of the ten
--   per-epoch values is used as the per-block figure.
--
-- ASSUMPTION (stated because the source does not define it): a pool minting N
--   blocks is assumed to earn N x (mean gross reward per block). That is the
--   expectation, not a guarantee -- per-block reward varies slightly with the
--   pool's own stake and pledge. This is a linear approximation.
--
-- CAVEAT (arithmetic, not advocacy): the ledger caps the operator's fixed cost
--   at the pool's actual reward pot for the epoch. A pool whose gross reward is
--   below 170 ADA does not pay a 170 ADA fee -- it takes the whole (smaller)
--   pot and members get nothing. So a share above 100% means "members receive
--   zero", not "the operator is owed more than the pool earned".
-- ============================================================================

WITH blocks AS (
  SELECT b.epoch_no, count(*) AS blocks_minted
  FROM block b JOIN slot_leader sl ON sl.id = b.slot_leader_id
  WHERE b.epoch_no BETWEEN 641 AND 650 AND sl.pool_hash_id IS NOT NULL
  GROUP BY 1
),
rew AS (
  SELECT earned_epoch AS epoch_no, sum(amount) AS gross_lovelace
  FROM reward
  WHERE earned_epoch BETWEEN 641 AND 650 AND type IN ('leader','member')
  GROUP BY 1
),
per_block AS (
  SELECT avg((r.gross_lovelace/1000000.0)/b.blocks_minted) AS ada_per_block
  FROM rew r JOIN blocks b ON b.epoch_no = r.epoch_no
),
params AS (
  SELECT (SELECT min_pool_cost/1000000.0 FROM epoch_param WHERE epoch_no = (SELECT max(no) FROM epoch)) AS current_floor_ada,
         75.0::numeric AS proposed_floor_ada,
         (SELECT ada_per_block FROM per_block) AS ada_per_block
),
sizes(blocks_per_epoch) AS (VALUES (1),(2),(5),(20))
SELECT s.blocks_per_epoch,
       p.ada_per_block::numeric(20,2)                                   AS gross_ada_per_block,
       (s.blocks_per_epoch * p.ada_per_block)::numeric(20,2)            AS gross_reward_ada,
       p.current_floor_ada::numeric(20,2)                               AS min_pool_cost_ada,
       round(100 * p.current_floor_ada / (s.blocks_per_epoch * p.ada_per_block), 1) AS pct_of_gross_at_170,
       round(100 * p.proposed_floor_ada / (s.blocks_per_epoch * p.ada_per_block), 1) AS pct_of_gross_at_75_proposed
FROM sizes s CROSS JOIN params p
ORDER BY s.blocks_per_epoch;

\echo ''
\echo '--- inputs used (for the record) ---'
WITH blocks AS (
  SELECT b.epoch_no, count(*) AS blocks_minted
  FROM block b JOIN slot_leader sl ON sl.id = b.slot_leader_id
  WHERE b.epoch_no BETWEEN 641 AND 650 AND sl.pool_hash_id IS NOT NULL GROUP BY 1
),
rew AS (
  SELECT earned_epoch AS epoch_no, sum(amount) AS gross_lovelace FROM reward
  WHERE earned_epoch BETWEEN 641 AND 650 AND type IN ('leader','member') GROUP BY 1
)
SELECT '641-650' AS epochs_used,
       avg((r.gross_lovelace/1000000.0)/b.blocks_minted)::numeric(20,2) AS mean_ada_per_block,
       (SELECT min_pool_cost/1000000.0 FROM epoch_param WHERE epoch_no=(SELECT max(no) FROM epoch))::numeric(20,2) AS current_min_pool_cost_ada
FROM rew r JOIN blocks b ON b.epoch_no = r.epoch_no;