local action_facade = require("clever_tee.action_facade")
local capabilities = require("clever_tee.capabilities")
local feedback_service = require("clever_tee.feedback_service")
local policy = require("clever_tee.policy")
local sequence_coordinator = require("clever_tee.sequence_coordinator")
local sequence_state = require("clever_tee.sequence_state")
local state_transitions = require("clever_tee.state_transitions")

local M = {}
local CompositionRoot = {}
CompositionRoot.__index = CompositionRoot
M.CompositionRoot = CompositionRoot
M.ACTION_NAMES = {
  "StartFindForward",
  "StartFindBackward",
  "StartTillForward",
  "StartTillBackward",
  "Reset",
  "RepeatSameDirection",
  "RepeatOppositeDirection",
}
M.DEFAULT_MAPPING_MODES = { "n", "x", "o" }
M.DEFAULT_MAPPING_OPTIONS = {
  silent = true,
  remap = false,
  preserve_count = true,
}
M.DEFAULT_MAPPINGS = {
  { lhs = "f", action = "StartFindForward" },
  { lhs = "F", action = "StartFindBackward" },
  { lhs = "t", action = "StartTillForward" },
  { lhs = "T", action = "StartTillBackward" },
}

local ACTION_INVOCATIONS = {
  StartFindForward = function(facade)
    return facade:start_find_forward()
  end,
  StartFindBackward = function(facade)
    return facade:start_find_backward()
  end,
  StartTillForward = function(facade)
    return facade:start_till_forward()
  end,
  StartTillBackward = function(facade)
    return facade:start_till_backward()
  end,
  Reset = function(facade)
    return facade:reset()
  end,
  RepeatSameDirection = function(facade)
    return facade:repeat_same_direction()
  end,
  RepeatOppositeDirection = function(facade)
    return facade:repeat_opposite_direction()
  end,
}

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

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

local function normalize_options(options)
  if type(options) ~= "table" then
    fail("CompositionRoot options must be a table", 3)
  end
  if options.host == nil then
    return { host = options }
  end
  return options
end

function CompositionRoot.new(options)
  if CompositionRoot.is(options) then
    return options
  end
  options = normalize_options(options)
  local host = capabilities.assert_implements(options.host)
  local state = sequence_state.new()
  local transitions = options.transitions
    or options.state_transitions
    or state_transitions.new(state)
  local policy_service = options.policy
    or options.policy_service
    or policy.new(host)
  local feedback = options.feedback
    or options.feedback_service
    or feedback_service.new({
      host = host,
      state = state,
      transitions = transitions,
      policy = policy_service,
    })
  local coordinator = options.coordinator
    or options.sequence_coordinator
    or sequence_coordinator.new({
      host = host,
      state = state,
      transitions = transitions,
      policy = policy_service,
      feedback = feedback,
    })
  local facade = options.facade
    or options.action_facade
    or action_facade.new({ coordinator = coordinator })

  local root = setmetatable({}, CompositionRoot)
  root_records[root] = {
    host = host,
    state = state,
    transitions = transitions,
    policy = policy_service,
    feedback = feedback,
    coordinator = coordinator,
    facade = facade,
    activation = nil,
    last_highlight_refresh = nil,
  }
  return root
end

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

local function register_logical_actions(record)
  local registrations = {}
  for _, name in ipairs(M.ACTION_NAMES) do
    local invoke = ACTION_INVOCATIONS[name]
    registrations[name] = record.host:register_action(name, function(...)
      return invoke(record.facade, ...)
    end)
  end
  return registrations
end

local function register_default_mappings(record, setup)
  local registrations = {}
  if not setup.install_default_mappings then
    return registrations
  end
  for _, mapping in ipairs(M.DEFAULT_MAPPINGS) do
    registrations[mapping.lhs] = record.host:register_mapping(
      M.DEFAULT_MAPPING_MODES,
      mapping.lhs,
      mapping.action,
      M.DEFAULT_MAPPING_OPTIONS
    )
  end
  return registrations
end

function CompositionRoot:activate()
  local record = root_records[self]
  if record.activation == nil then
    local setup = record.policy:capture_activation()
    local feedback_activation = record.feedback:activate()
    local highlights = record.feedback:evaluate_highlights()
    local colorscheme_registration = record.host:register_events(
      "ColorScheme",
      function()
        record.last_highlight_refresh = record.feedback:evaluate_highlights()
      end,
      { owner = "clever_tee", lifecycle = "colorscheme" }
    )
    local actions = register_logical_actions(record)
    record.activation = {
      state = record.state,
      setup = setup,
      feedback = feedback_activation,
      highlights = highlights,
      colorscheme_registration = colorscheme_registration,
      actions = actions,
      mappings = register_default_mappings(record, setup),
    }
  end
  return record.activation
end

function CompositionRoot:last_highlight_refresh()
  return root_records[self].last_highlight_refresh
end

function CompositionRoot:host()
  return root_records[self].host
end

function CompositionRoot:state()
  return root_records[self].state
end

function CompositionRoot:transitions()
  return root_records[self].transitions
end

function CompositionRoot:policy()
  return root_records[self].policy
end

function CompositionRoot:feedback()
  return root_records[self].feedback
end

function CompositionRoot:coordinator()
  return root_records[self].coordinator
end

function CompositionRoot:facade()
  return root_records[self].facade
end

function CompositionRoot:invoke_descriptor(value)
  return self:facade():invoke_descriptor(value)
end

function CompositionRoot:diagnostic_full_reset()
  return self:facade():diagnostic_full_reset()
end

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

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

return M