# Brackets use cumulative upper bounds, with a final uncapped bracket.
def progressive_points($qty; $brackets):
  reduce $brackets[] as $b
    ({remaining: $qty, lower: 0, points: 0};
     (if $b.upTo == null then .remaining
      else ([.remaining, ($b.upTo - .lower)] | min) end) as $units
     | .points += $units * $b.pointsPerUnit
     | .remaining -= $units
     | .lower = ($b.upTo // .lower))
  | .points;

def reward_buckets($rules):
  ($rules.skuRules | INDEX(.sku)) as $bySku
  | group_by([.accountId, .sku])
  | map(
      .[0] as $first
      | (map(.netQty) | add) as $qty
      | ($rules.tierMultipliers[$first.tier]
         // error("unknown account tier: " + $first.tier)) as $multiplier
      | $bySku[$first.sku] as $rule
      | (if $rule == null then 0
         else progressive_points($qty; $rule.brackets) end) as $base
      | {accountId: $first.accountId, sku: $first.sku,
         netQty: $qty, basePoints: $base, multiplier: $multiplier,
         points: ($base * $multiplier), missingRate: ($rule == null)});