local domain = require("clever_f.domain")
local sequence_state = require("clever_f.sequence_state")

local M = {}
local RepeatResolver = {}
M.RepeatResolver = RepeatResolver

M.Decision = {
  ACQUIRE = "acquire",
  REPEAT = "repeat",
}
M.ACQUIRE = M.Decision.ACQUIRE
M.REPEAT = M.Decision.REPEAT

local resolver_records = setmetatable({}, { __mode = "k" })

local function fail(message, level)
  error(message, (level or 1) + 1)
end

local resolver_metatable = {
  __index = RepeatResolver,
  __newindex = function()
    fail("RepeatResolver values are immutable", 2)
  end,
  __tostring = function()
    return "repeat-resolver"
  end,
  __metatable = "clever_f.repeat_resolver.RepeatResolver",
}

function RepeatResolver.new(options)
  if RepeatResolver.is(options) then
    return options
  end
  if options == nil then
    options = {}
  elseif sequence_state.is(options) then
    options = { state = options }
  elseif type(options) ~= "table" then
    fail("RepeatResolver options must be a table", 2)
  end

  local state = options.state or sequence_state.get()
  if not sequence_state.is(state) then
    fail("RepeatResolver state must be the plugin-global SequenceState", 2)
  end

  local resolver = setmetatable({}, resolver_metatable)
  resolver_records[resolver] = {
    state = state,
  }
  return resolver
end

function RepeatResolver.is(value)
  return type(value) == "table" and resolver_records[value] ~= nil
end

function RepeatResolver:previous_landing(context)
  context = domain.ModeContext.from_full_mode(context)
  return resolver_records[self].state:get_previous_landing(context)
end

function RepeatResolver:decide(context, current_position, macro_state)
  current_position = domain.Position.coerce(current_position)
  local landing = self:previous_landing(context)
  if landing == nil or not domain.Position.equal(landing, current_position) then
    return M.Decision.ACQUIRE
  end
  if domain.MacroState.new(macro_state).executing then
    return M.Decision.ACQUIRE
  end
  return M.Decision.REPEAT
end

RepeatResolver.eligibility = RepeatResolver.decide
RepeatResolver.resolve_eligibility = RepeatResolver.decide

function M.new(options)
  return RepeatResolver.new(options)
end

M.landing = function(context, options)
  return RepeatResolver.new(options):previous_landing(context)
end

function M.decide(context, current_position, macro_state, options)
  return RepeatResolver.new(options):decide(
    context,
    current_position,
    macro_state
  )
end

M.eligibility = M.decide

setmetatable(M, {
  __call = function(_, options)
    return RepeatResolver.new(options)
  end,
})

return M