## Default-parity + registration guard for the LEADGAIN gun (id 16).
##
## No Java, no battle, no network build. Covers:
##   * the rack table carries LEADGAIN at id 16 and it defaults to `off`;
##   * the shipped rack still admits exactly Pattern;
##   * TR_RACK_LEADGAIN=both is what admits it, and the spawn gate honours it;
##     (the LEGACY TR_RACK_BITBRAIN alias is pinned by
##     `test_lead_gain_legacy.nim`);
##   * `initLeadGainGun()` is LAZY (no learner) and does NOT touch the global
##     RNG, so the default path cannot perturb the selector's random draws;
##   * the mode parser defaults to `perRound`.
##
## Run: nim c -r common_libs/tests/test_lead_gain_registration.nim

import std/[random, os, math]
import gun_harness/virtual_bullets
import gun_harness/selector
import guns/lead_gain

const LeadGainId = 16
const PatternId  = 5

var failures = 0
proc check(name: string, ok: bool) =
  if ok: echo "PASS: ", name
  else: echo "FAIL: ", name; inc failures

proc clearRackEnv() =
  for name in RackGunNames: delEnv("TR_RACK_" & name)

proc testTable() =
  check "rack: LEADGAIN is registered at id 16", RackGunNames[LeadGainId] == "LEADGAIN"
  check "rack: LEADGAIN defaults to `off`", DefaultRackMembership[LeadGainId] == rmOff
  var onlyPattern = true
  for i in 0..<RackGunNames.len:
    let want = if i == PatternId: rmBoth else: rmOff
    if DefaultRackMembership[i] != want: onlyPattern = false
  check "rack: the shipped default is still the onlyPattern rack", onlyPattern
  check "rack: the default rack admits only Pattern (1v1)",
        admittedGuns(NumRackGuns, rm1v1, DefaultRackMembership) == @[PatternId]
  check "gate: LEADGAIN is NOT spawned under the default rack",
        not vBulletAdmitted(LeadGainId, rm1v1, DefaultRackMembership, true)

proc testEnvOverride() =
  clearRackEnv()
  putEnv("TR_RACK_LEADGAIN", "both")
  let m = loadRackMembership()
  check "env: TR_RACK_LEADGAIN=both admits LEADGAIN",
        m[LeadGainId] == rmBoth and
        vBulletAdmitted(LeadGainId, rm1v1, m, true)
  check "env: admitting LEADGAIN leaves Pattern as the only other member",
        admittedGuns(NumRackGuns, rm1v1, m) == @[PatternId, LeadGainId]
  clearRackEnv()

proc testLazyAndRngClean() =
  delEnv("TR_LEADGAIN_MEM"); delEnv("TR_BITBRAIN_MEM")
  var g = initLeadGainGun()
  check "lazy: constructing the gun does NOT build the learner (0 bytes)",
        g.networkBytes == 0
  check "default: unset TR_LEADGAIN_MEM is perRound",
        g.memMode == lgPerRound
  check "parse: retained/decay/unknown", 
        parseLgMemMode("retained") == lgRetained and
        parseLgMemMode("decay") == lgDecay and
        parseLgMemMode("banana") == lgPerRound
  # Global RNG parity: constructing the gun must not consume global randomness.
  randomize(1234)
  let a = rand(1_000_000)
  randomize(1234)
  var g2 = initLeadGainGun()
  discard g2
  let b = rand(1_000_000)
  check "parity: initLeadGainGun() does not perturb the global RNG", a == b

proc testGeometry() =
  check "geometry: class 0 centre is the low edge + half a bin",
        abs(lgCenterDeg(0, 32, 40.0) - (-40.0 + 0.5 * 80.0 / 32.0)) < 1e-9
  check "geometry: lgClassOf round-trips the centre",
        lgClassOf(degToRad(lgCenterDeg(17, 32, 40.0)), 32, 40.0) == 17

testTable()
testEnvOverride()
testLazyAndRngClean()
testGeometry()

if failures > 0:
  echo "\n", failures, " check(s) FAILED"
  quit(1)
echo "\nAll LEADGAIN registration checks passed."