path: root/lua/clever_f/feedback_service.lua

local domain = require("clever_f.domain")
local policy = require("clever_f.policy")
local state_transitions = require("clever_f.state_transitions")

local M = {}
local FeedbackService = {}
FeedbackService.__index = FeedbackService
M.FeedbackService = FeedbackService
local CursorPresentationLease = {}
M.CursorPresentationLease = CursorPresentationLease

M.DEFAULT_LABEL_GROUP = "CleverFDefaultLabel"
M.Priority = {
  HIGH = "high",
  ORDINARY = "ordinary",
}

local OVERLAY_PRIORITIES = {
  CleverFCursor = M.Priority.HIGH,
  CleverFChar = M.Priority.HIGH,
  CleverFDirect = M.Priority.ORDINARY,
}

local service_records = setmetatable({}, { __mode = "k" })
local cursor_lease_records = setmetatable({}, { __mode = "k" })
local temporary_release_records = setmetatable({}, { __mode = "k" })

local FEATURE_GROUPS = {
  "CleverFCursor",
  "CleverFChar",
  "CleverFDirect",
}

local DEFAULT_LABEL_DEFINITION = {
  guifg = "red",
  guibg = "NONE",
  gui = {
    bold = true,
    underline = true,
  },
  ctermfg = "red",
  ctermbg = "NONE",
  cterm = {
    bold = true,
    underline = true,
  },
}

local function copy(value)
  if type(value) ~= "table" then
    return value
  end
  local result = {}
  for key, item in pairs(value) do
    result[key] = copy(item)
  end
  return result
end

function M.default_label_definition()
  return copy(DEFAULT_LABEL_DEFINITION)
end

function M.overlay_priority(group)
  local priority = OVERLAY_PRIORITIES[group]
  if priority == nil then
    error("unknown feedback overlay group '" .. tostring(group) .. "'", 2)
  end
  return priority
end

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

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

local function require_host(host)
  if type(host) ~= "table"
    or type(host.read_highlight_group) ~= "function"
    or type(host.define_highlight_group) ~= "function"
    or type(host.create_highlight) ~= "function"
    or type(host.remove_highlight) ~= "function"
    or type(host.supports_cursor_presentation) ~= "function"
    or type(host.suppress_cursor_presentation) ~= "function"
    or type(host.restore_cursor_presentation) ~= "function"
  then
    fail("FeedbackService host must provide highlight groups", 3)
  end
  return host
end

local function require_transitions(transitions, state)
  transitions = transitions or state_transitions.new(state)
  if type(transitions) ~= "table"
    or type(transitions.AddTemporaryOverlay) ~= "function"
    or type(transitions.RemoveTemporaryOverlay) ~= "function"
  then
    fail("FeedbackService transitions must manage temporary overlays", 3)
  end
  return transitions
end

local function require_policy(service, host)
  service = service or policy.new(host)
  if type(service) ~= "table"
    or type(service.evaluate_highlight_links) ~= "function"
    or type(service.sample_acquisition) ~= "function"
  then
    fail("FeedbackService policy must evaluate highlight links", 3)
  end
  return service
end

function FeedbackService.new(options)
  if FeedbackService.is(options) then
    return options
  end
  options = normalize_options(options)
  local service = setmetatable({}, FeedbackService)
  local host = require_host(options.host)
  service_records[service] = {
    host = host,
    policy = require_policy(options.policy or options.policy_service, host),
    transitions = require_transitions(
      options.transitions or options.state_transitions,
      options.state
    ),
    persistent_requests = {},
  }
  return service
end

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

local cursor_lease_metatable = {
  __index = function(lease, key)
    local method = CursorPresentationLease[key]
    if method ~= nil then
      return method
    end
    local record = cursor_lease_records[lease]
    if key == "identity" then
      return record.identity
    end
    if key == "active" then
      return record.active
    end
    return nil
  end,
  __newindex = function()
    fail("cursor presentation leases are read-only", 2)
  end,
  __metatable = "clever_f.feedback_service.CursorPresentationLease",
}

local function new_cursor_presentation_lease(host, suppress)
  local lease = setmetatable({}, cursor_lease_metatable)
  local identity = suppress and host:suppress_cursor_presentation() or nil
  cursor_lease_records[lease] = {
    host = host,
    identity = identity,
    active = identity ~= nil,
  }
  return lease
end

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

function CursorPresentationLease:release()
  local record = cursor_lease_records[self]
  if record == nil then
    fail("cursor presentation lease is invalid", 2)
  end
  if not record.active then
    return false
  end
  record.active = false
  record.host:restore_cursor_presentation(record.identity)
  return true
end

function FeedbackService:create_cursor_presentation_lease(enabled)
  local record = service_records[self]
  if enabled == nil then
    enabled = record.policy:sample_acquisition().hide_cursor_on_cmdline
  elseif type(enabled) ~= "boolean" then
    fail("cursor presentation policy must be a Boolean", 2)
  end
  local supported = enabled and record.host:supports_cursor_presentation()
  return new_cursor_presentation_lease(record.host, supported == true)
end

local function position_list(positions)
  if type(positions) ~= "table" then
    fail("direct marker positions must be a list", 3)
  end
  local result = {}
  local item_count = 0
  for key, position in pairs(positions) do
    if type(key) ~= "number"
      or key ~= math.floor(key)
      or key < 1
      or key > #positions
    then
      fail("direct marker positions must be a list", 3)
    end
    result[key] = domain.Position.coerce(position)
    item_count = item_count + 1
  end
  if item_count ~= #positions then
    fail("direct marker positions must be a list", 3)
  end
  return result
end

function FeedbackService:create_direct_markers(positions, window)
  positions = position_list(positions)
  if #positions == 0 then
    return nil
  end
  if window == nil then
    fail("direct marker window must identify its host window", 2)
  end

  local record = service_records[self]
  local identity = record.host:create_highlight({
    group = "CleverFDirect",
    window = window,
    positions = positions,
    priority = M.overlay_priority("CleverFDirect"),
  })
  record.transitions:AddTemporaryOverlay(identity, window, "CleverFDirect")
  local resource = {
    identity = identity,
    window = window,
    group = "CleverFDirect",
    positions = positions,
  }
  temporary_release_records[resource] = false
  return resource
end

function FeedbackService:create_cursor_marker(position, window)
  position = domain.Position.coerce(position)
  if window == nil then
    fail("cursor marker window must identify its host window", 2)
  end

  local record = service_records[self]
  local identity = record.host:create_highlight({
    group = "CleverFCursor",
    window = window,
    position = position,
    priority = M.overlay_priority("CleverFCursor"),
  })
  record.transitions:AddTemporaryOverlay(identity, window, "CleverFCursor")
  local resource = {
    identity = identity,
    window = window,
    group = "CleverFCursor",
    position = position,
  }
  temporary_release_records[resource] = false
  return resource
end

function FeedbackService:remove_temporary_overlay(resource)
  if type(resource) ~= "table" or resource.identity == nil then
    fail("temporary overlay resource must identify its highlight", 2)
  end
  if temporary_release_records[resource] == true then
    return false
  end
  temporary_release_records[resource] = true
  local record = service_records[self]
  local ok, removed = pcall(
    record.host.remove_highlight,
    record.host,
    resource.identity
  )
  record.transitions:RemoveTemporaryOverlay(resource.identity, resource.window)
  if not ok then
    error(removed, 0)
  end
  return removed
end

function M.persistent_context_eligible(context)
  context = domain.ModeContext.from_full_mode(context)
  return context.key == "n"
    or context.visual_kind ~= nil
    or context.select_kind ~= nil
    or context.key == "cv"
    or context.key == "cvr"
end

function FeedbackService:request_persistent(specification)
  if type(specification) ~= "table" then
    fail("persistent feedback request must be a table", 2)
  end
  local context = domain.ModeContext.from_full_mode(specification.context)
  if not M.persistent_context_eligible(context) then
    fail("persistent feedback request requires an eligible context", 2)
  end
  if not domain.TargetPlan.is(specification.target_plan) then
    fail("persistent feedback request requires a TargetPlan", 2)
  end
  if not domain.ResolvedMotionPlan.is(specification.motion_plan) then
    fail("persistent feedback request requires a ResolvedMotionPlan", 2)
  end
  local request = {
    context = context,
    anchor = domain.Position.coerce(specification.anchor),
    target_plan = specification.target_plan,
    motion_plan = specification.motion_plan,
    window = specification.window,
  }
  local requests = service_records[self].persistent_requests
  requests[#requests + 1] = request
  return request
end

function FeedbackService:persistent_requests()
  local result = {}
  for index, request in ipairs(service_records[self].persistent_requests) do
    result[index] = request
  end
  return result
end

function FeedbackService:evaluate_feature_links()
  local record = service_records[self]
  local rules = record.policy:evaluate_highlight_links()
  local results = {}
  for _, group in ipairs(FEATURE_GROUPS) do
    local rule = rules[group]
    if rule.enabled then
      if rule.configured_target ~= nil then
        record.host:define_highlight_group(
          group,
          { link = rule.configured_target },
          { force = true }
        )
        results[group] = {
          group = group,
          target = rule.configured_target,
          source = "configured",
          applied = true,
        }
      else
        local existing = record.host:read_highlight_group(group)
        if existing ~= nil then
          results[group] = {
            group = group,
            definition = existing,
            source = "colorscheme",
            applied = false,
          }
        else
          record.host:define_highlight_group(
            group,
            { link = rule.target },
            { default = true }
          )
          results[group] = {
            group = group,
            target = rule.target,
            source = "fallback",
            applied = true,
          }
        end
      end
    end
  end
  return results
end

function FeedbackService:ensure_default_label()
  local existing = service_records[self].host:read_highlight_group(
    M.DEFAULT_LABEL_GROUP
  )
  if existing ~= nil then
    return {
      group = M.DEFAULT_LABEL_GROUP,
      definition = existing,
      source = "colorscheme",
      applied = false,
    }
  end

  local definition = M.default_label_definition()
  service_records[self].host:define_highlight_group(
    M.DEFAULT_LABEL_GROUP,
    definition,
    { default = true }
  )
  return {
    group = M.DEFAULT_LABEL_GROUP,
    definition = definition,
    source = "fallback",
    applied = true,
  }
end

function FeedbackService:evaluate_highlights()
  return {
    default_label = self:ensure_default_label(),
    feature_links = self:evaluate_feature_links(),
  }
end

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

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

return M