gen1recomp/src/battle/Status.lua

-- Per-turn status/volatile condition handling (Gen 1 semantics).
--
-- The persistent conditions live in Status.RECORDS; a battle passes its
-- merged Data.statuses so mod statuses join the same beforeMove gauntlet
-- and residual sweep.  Callers without a battle (pure-module tests) fall
-- back to the vanilla records, which is bit-identical behavior.

local Strings = require("src.core.Strings")
local romText = require("src.core.RomText")

local Status = {}

-- pokered's <USER>/<TARGET> text macros print "Enemy " before the enemy
-- mon's nickname; these records only know the raw name -- BattleState
-- splices the prefix in (prefixEnemy), same as always
local function name(battler)
  return battler.name
end

-- statuses with beforeMovePriority above this run before the engine's
-- held/disable/confusion volatiles; at or below, after (sleep 40 and
-- freeze 30 come first, paralysis 10 comes last, like the original
-- CheckPlayerStatusConditions order)
local VOLATILE_PRIORITY = 20

local function hasType(battler, wanted)
  for _, t in ipairs(battler.curTypes or {}) do
    if t == wanted then return true end
  end
  return false
end

-- shared PSN/BRN residual: 1/16 max HP, multiplied (and advanced) by the
-- Toxic counter (HandlePoisonBurnLeechSeed).  The caller passes the whole
-- sentence rather than the noun: "hurt by poison" and "hurt by the burn"
-- decline differently once translated, so a shared fragment cannot be the
-- translatable unit.
local function damageOverTime(label, template)
  return function(battler, _, battle)
    local mon = battler.mon
    local base = math.max(1, math.floor(mon.stats.hp / 16))
    local dmg = base
    if battler.toxicCounter then
      dmg = base * battler.toxicCounter
      battler.toxicCounter = battler.toxicCounter + 1
    end
    mon.hp = math.max(0, mon.hp - dmg)
    return { romText(battle and battle.data, label, template, name(battler)) }
  end
end

-- Labels stay plain literals on purpose: this table is built at require
-- time, before Strings.load has a catalog, so a Strings() here would
-- freeze the English.  They are already translatable through the
-- statuses registry (mod.content.statuses:patch(id, { label = ... })).
--
-- The five persistent conditions as records: the beforeMove gauntlet, the
-- residual sweep, the inflict text/immunities (StatusRegistry.inflict),
-- the catch/wobble bonuses (Catching.attempt), the HUD label, and the
-- burn/paralysis stat cut (Damage.compute, TurnOrder.effectiveSpeed) all
-- read these fields, so a mod's sixth status plugs into every consumer.
Status.RECORDS = {
  SLP = {
    id = "SLP", label = "SLP", hudLabel = "SLP",
    catchBonus = 25, shakeBonus = 10,
    beforeMovePriority = 40,
    beforeMove = function(battler, _, battle)
      battler.sleepTurns = (battler.sleepTurns or 1) - 1
      if battler.sleepTurns <= 0 then
        battler.mon.status = nil
        -- wakes, loses the turn
        return false, { romText(battle and battle.data, "_WokeUpText",
          "%s\nwoke up!", name(battler)) }
      end
      return false, { romText(battle and battle.data, "_FastAsleepText",
        "%s\nis fast asleep!", name(battler)) }
    end,
    onInflict = function(battle, target, opts, display)
      target.sleepTurns = battle.rng(1, 7)
      return { romText(battle.data, "_FellAsleepText",
        "%s\nfell asleep!", display) }
    end,
  },
  FRZ = {
    id = "FRZ", label = "FRZ", hudLabel = "FRZ",
    catchBonus = 25, shakeBonus = 10,
    beforeMovePriority = 30,
    beforeMove = function(battler, _, battle)
      return false, { romText(battle and battle.data, "_IsFrozenText",
        "%s\nis frozen solid!", name(battler)) }
    end,
    canInflict = function(target) return not hasType(target, "ICE") end,
    onInflict = function(battle, _, _, display)
      return { romText(battle and battle.data, "_FrozenText",
        "%s\nwas frozen solid!", display) }
    end,
  },
  PSN = {
    id = "PSN", label = "PSN", hudLabel = "PSN",
    catchBonus = 12, shakeBonus = 5,
    residual = damageOverTime("_HurtByPoisonText",
      Strings.source("%s's\nhurt by poison!")),
    canInflict = function(target) return not hasType(target, "POISON") end,
    onInflict = function(battle, target, opts, display)
      if opts.toxic then
        target.toxicCounter = 1
        return { romText(battle and battle.data, "_BadlyPoisonedText",
          "%s's\nbadly poisoned!", display) }
      end
      return { romText(battle and battle.data, "_PoisonedText",
        "%s\nwas poisoned!", display) }
    end,
  },
  BRN = {
    id = "BRN", label = "BRN", hudLabel = "BRN",
    catchBonus = 12, shakeBonus = 5,
    statPenalty = { stat = "attack", div = 2 },
    residual = damageOverTime("_HurtByBurnText",
      Strings.source("%s's\nhurt by the burn!")),
    canInflict = function(target) return not hasType(target, "FIRE") end,
    onInflict = function(battle, _, _, display)
      return { romText(battle and battle.data, "_BurnedText",
        "%s\nwas burned!", display) }
    end,
  },
  PAR = {
    id = "PAR", label = "PAR", hudLabel = "PAR",
    catchBonus = 12, shakeBonus = 5,
    statPenalty = { stat = "speed", div = 4 },
    beforeMovePriority = 10,
    beforeMove = function(battler, rng, battle)
      -- cp 25 percent / jr nc: fully paralyzed on rand < 63 (63/256)
      if rng(0, 255) < 63 then
        return false, { romText(battle and battle.data, "_FullyParalyzedText",
          "%s's\nfully paralyzed!", name(battler)) }
      end
      return true, {}
    end,
    canInflict = function(target, opts)
      -- ParalyzeEffect_: Electric-type moves can't paralyze Ground-types
      return not (opts.moveType == "ELECTRIC" and hasType(target, "GROUND"))
    end,
    onInflict = function(battle, _, _, display)
      -- primary and secondary paralysis share this line
      return { romText(battle and battle.data, "_ParalyzedMayNotAttackText",
        "%s's\nparalyzed! It may\nnot attack!", display) }
    end,
  },
}

function Status.registerInto(registry, _, owner)
  for id, record in pairs(Status.RECORDS) do
    registry:register(id, record, owner)
  end
end

-- the merged view when a battle is on hand, the vanilla records otherwise
function Status.recordFor(statuses, id)
  if id == nil then return nil end
  return (statuses or Status.RECORDS)[id]
end

local function battleStatuses(battle)
  return battle and battle.data and battle.data.statuses
end

-- Returns canMove, messages, selfHit (true -> hurt itself in confusion).
-- The active status record's beforeMove runs at its priority slot: above
-- VOLATILE_PRIORITY before the held/disable/confusion block (sleep,
-- freeze), at or below after it (paralysis) -- the original's order.
function Status.beforeMove(battler, rng, battle, selectedMoveId)
  local mon = battler.mon
  -- Haze curing this mon's sleep/freeze forfeits its pending move for
  -- the turn, silently (haze.asm writes $ff/CANNOT_MOVE to the selected
  -- move; ExecuteMove returns immediately without a message)
  if battler.skipMove then
    battler.skipMove = nil
    return false, {}
  end
  if battler.flinched then
    battler.flinched = false
    return false, { romText(battle and battle.data, "_FlinchedText",
      "%s\nflinched!", name(battler)) }
  end
  local record = Status.recordFor(battleStatuses(battle), mon.status)
  local handler = record and record.beforeMove
  local priority = handler and (record.beforeMovePriority or 0)
  local msgs = {}
  local function runStatus()
    local canMove, statusMsgs, selfHit = handler(battler, rng, battle)
    for _, m in ipairs(statusMsgs or {}) do msgs[#msgs + 1] = m end
    return canMove, selfHit
  end
  if handler and priority > VOLATILE_PRIORITY then
    local canMove, selfHit = runStatus()
    if not canMove or selfHit then return canMove, msgs, selfHit end
    handler = nil
  end
  if battler.boundTurns and battler.boundTurns > 0 then
    battler.boundTurns = battler.boundTurns - 1
    msgs[#msgs + 1] = romText(battle and battle.data, "_CantMoveText",
      "%s\ncan't move!", name(battler))
    return false, msgs
  end
  if battler.disabledTurns then
    battler.disabledTurns = battler.disabledTurns - 1
    if battler.disabledTurns <= 0 then
      battler.disabledTurns, battler.disabledSlot = nil, nil
      table.insert(msgs, romText(battle and battle.data, "_DisabledNoMoreText",
        "%s's\ndisabled no more!", name(battler)))
    end
  end
  if battler.confusedTurns then
    battler.confusedTurns = battler.confusedTurns - 1
    if battler.confusedTurns <= 0 then
      battler.confusedTurns = nil
      table.insert(msgs, romText(battle and battle.data, "_ConfusedNoMoreText",
        "%s\nsnapped out of\nconfusion!", name(battler)))
    else
      table.insert(msgs, romText(battle and battle.data, "_IsConfusedText",
        "%s\nis confused!", name(battler)))
      -- cp 50 percent + 1 / jr c: hurt itself on rand >= 128 (128/256)
      if rng(0, 255) < 128 then
        return false, msgs, true -- hurt itself
      end
    end
  end
  -- .TriedToUseDisabledMoveCheck (engine/battle/core.asm, and the enemy
  -- copy .checkIfTriedToUseDisabledMove): the disabled-move test runs at
  -- EXECUTION time, comparing wPlayerDisabledMoveNumber against the
  -- already SELECTED move, so a Disable that lands earlier in the same
  -- turn still blocks the slower mon's move (#860).  It sits after the
  -- confusion block and before the paralysis roll, so a confusion self-hit
  -- still pre-empts it and the paralysis roll is never spent on a turn the
  -- disable eats.  PrintMoveIsDisabledText clears CHARGING_UP before
  -- printing, so a disabled charge move drops its stored turn instead of
  -- releasing later.
  if selectedMoveId and battler.disabledSlot then
    local disabled = (battler.curMoves or {})[battler.disabledSlot]
    if disabled and disabled.id == selectedMoveId then
      battler.charging, battler.chargeReady = nil, nil
      local moves = battle and battle.data and battle.data.moves
      local shown = moves and moves[selectedMoveId] and moves[selectedMoveId].name
                    or tostring(selectedMoveId)
      table.insert(msgs, romText(battle and battle.data, "_MoveIsDisabledText",
        "%s's\n%s is\ndisabled!", name(battler), shown))
      return false, msgs
    end
  end
  if handler then
    local canMove, selfHit = runStatus()
    if not canMove or selfHit then return canMove, msgs, selfHit end
  end
  return true, msgs
end

-- End-of-turn residual damage; opponent is needed for Leech Seed.
-- Returns messages.
function Status.residual(battler, opponent, battle)
  local msgs = {}
  local mon = battler.mon
  -- the Haze move-forfeit only covers the turn Haze was used; if this
  -- mon had already moved, drop the flag before it leaks into next turn
  battler.skipMove = nil
  if mon.hp <= 0 then return msgs end
  local record = Status.recordFor(battleStatuses(battle), mon.status)
  if record and record.residual then
    for _, m in ipairs(record.residual(battler, opponent, battle) or {}) do
      msgs[#msgs + 1] = m
    end
  end
  if battler.leechSeeded and mon.hp > 0 and opponent.mon.hp > 0 then
    -- the shared Toxic counter multiplies (and advances on) the seed
    -- drain too -- the Gen 1 Leech Seed glitch
    -- (HandlePoisonBurnLeechSeed_DecreaseOwnHP)
    local dmg = math.max(1, math.floor(mon.stats.hp / 16))
    if battler.toxicCounter then
      dmg = dmg * battler.toxicCounter
      battler.toxicCounter = battler.toxicCounter + 1
    end
    dmg = math.min(dmg, mon.hp)
    mon.hp = mon.hp - dmg
    opponent.mon.hp = math.min(opponent.mon.stats.hp, opponent.mon.hp + dmg)
    table.insert(msgs, romText(battle and battle.data, "_HurtByLeechSeedText",
      "LEECH SEED saps\n%s!", name(battler)))
  end
  return msgs
end

return Status