--- @section Meter
local METER_MAX = 1000
local METER_DEFAULT = 500
local METER_GAIN_PER_CHORE = 100
local METER_DECAY_PER_DAY = 20
local COMBO_BASE_BONUS = 0.02
local COMBO_MAX_BONUS = 0.16
local COMBO_TIMEOUT_FRAMES = 600

-- Internal meters for tracking game progress and player stats.
Meter.COLOR_ISM = Config.colors.red
Meter.COLOR_WPM = Config.colors.blue
Meter.COLOR_BM = Config.colors.black
Meter.COLOR_BG = Config.colors.meter_bg

--- Gets initial meter values.
--- @within Meter
--- @return result table Initial meter values. </br>
--- Fields: </br>
--- * ism (number) Initial ISM meter value.<br/>
--- * wpm (number) Initial WPM meter value.<br/>
--- * bm (number) Initial BM meter value.<br/>
--- * combo (number) Current combo count.<br/>
--- * combo_timer (number) Frames since last combo action.<br/>
--- * hidden (boolean) Whether meters are hidden.
function Meter.get_initial()
  return {
    ism = METER_DEFAULT,
    wpm = METER_DEFAULT,
    bm = METER_DEFAULT,
    combo = 0,
    combo_timer = 0,
    hidden = false,
  }
end

--- Hides meters.
--- @within Meter
function Meter.hide()
  if Context and Context.meters then Context.meters.hidden = true end
end

--- Shows meters.
--- @within Meter
function Meter.show()
  if Context and Context.meters then Context.meters.hidden = false end
end

--- Gets max meter value.
--- @within Meter
--- @return number The maximum meter value.
function Meter.get_max()
  return METER_MAX
end

--- Sets the decay amount applied to all meters per day.
--- @within Meter
--- @param amount number Amount to subtract from each meter.
function Meter.set_decay(amount)
  METER_DECAY_PER_DAY = amount
end

--- Gets the meter decay as a percentage of the max meter value.
--- @within Meter
--- @return number The decay percentage per day.
function Meter.get_decay_percentage()
  return math.floor(METER_DECAY_PER_DAY / METER_MAX * 100)
end

--- Gets combo multiplier.
--- @within Meter
--- @return number The current combo multiplier.
function Meter.get_combo_multiplier()
  if not Context or not Context.meters then return 1 end
  local combo = Context.meters.combo
  if combo == 0 then return 1 end
  return 1 + math.min(COMBO_MAX_BONUS, COMBO_BASE_BONUS * (2 ^ (combo - 1)))
end

--- Updates all meters.
--- @within Meter
function Meter.update()
  if not Context or not Context.game_in_progress or not Context.meters then return end
  local m = Context.meters
  local in_minigame = string.find(Window.get_current_id(), "^minigame_") ~= nil
  if not in_minigame then
    if m.combo > 0 then
      m.combo_timer = m.combo_timer + 1
      if m.combo_timer >= COMBO_TIMEOUT_FRAMES then
        m.combo = 0
        m.combo_timer = 0
      end
    end
  end
end

--- Adds amount to a meter.
--- @within Meter
--- @param key string The meter key (e.g., "wpm", "ism", "bm").
--- @param amount number The amount to add.
function Meter.add(key, amount)
  if not Context or not Context.meters then return end
  local m = Context.meters
  if m[key] ~= nil then
    m[key] = math.min(METER_MAX, m[key] + amount)
  end
end

--- Called on minigame completion.
--- @within Meter
function Meter.on_minigame_complete()
  local m = Context.meters
  local gain = math.floor(METER_GAIN_PER_CHORE * Meter.get_combo_multiplier())
  Meter.add("wpm", gain)
  Meter.add("ism", gain)
  Meter.add("bm", gain)
  m.combo = m.combo + 1
  m.combo_timer = 0
end