1 files changed, 250 insertions, 0 deletions
diff --git a/lua/blink/cmp/completion/list.lua b/lua/blink/cmp/completion/list.lua
new file mode 100644
index 0000000..61fa2c3
--- /dev/null
+++ b/lua/blink/cmp/completion/list.lua
@@ -0,0 +1,250 @@
+--- Manages most of the state for the completion list such that downstream consumers can be mostly stateless
+--- @class (exact) blink.cmp.CompletionList
+--- @field config blink.cmp.CompletionListConfig
+--- @field show_emitter blink.cmp.EventEmitter<blink.cmp.CompletionListShowEvent>
+--- @field hide_emitter blink.cmp.EventEmitter<blink.cmp.CompletionListHideEvent>
+--- @field select_emitter blink.cmp.EventEmitter<blink.cmp.CompletionListSelectEvent>
+--- @field accept_emitter blink.cmp.EventEmitter<blink.cmp.CompletionListAcceptEvent>
+---
+--- @field context? blink.cmp.Context
+--- @field items blink.cmp.CompletionItem[]
+--- @field selected_item_idx? number
+--- @field preview_undo? { text_edit: lsp.TextEdit, cursor: integer[]?}
+---
+--- @field show fun(context: blink.cmp.Context, items: table<string, blink.cmp.CompletionItem[]>)
+--- @field fuzzy fun(context: blink.cmp.Context, items: table<string, blink.cmp.CompletionItem[]>): blink.cmp.CompletionItem[]
+--- @field hide fun()
+---
+--- @field get_selected_item fun(): blink.cmp.CompletionItem?
+--- @field get_selection_mode fun(context: blink.cmp.Context): { preselect: boolean, auto_insert: boolean }
+--- @field get_item_idx_in_list fun(item?: blink.cmp.CompletionItem): number?
+--- @field select fun(idx?: number, opts?: { auto_insert?: boolean, undo_preview?: boolean, is_explicit_selection?: boolean })
+--- @field select_next fun(opts?: blink.cmp.CompletionListSelectOpts)
+--- @field select_prev fun(opts?: blink.cmp.CompletionListSelectOpts)
+---
+--- @field undo_preview fun()
+--- @field apply_preview fun(item: blink.cmp.CompletionItem)
+--- @field accept fun(opts?: blink.cmp.CompletionListAcceptOpts): boolean Applies the currently selected item, returning true if it succeeded
+
+--- @class blink.cmp.CompletionListSelectOpts
+--- @field auto_insert? boolean When `true`, inserts the completion item automatically when selecting it
+
+--- @class blink.cmp.CompletionListSelectAndAcceptOpts
+--- @field callback? fun() Called after the item is accepted
+
+--- @class blink.cmp.CompletionListAcceptOpts : blink.cmp.CompletionListSelectAndAcceptOpts
+--- @field index? number The index of the item to accept, if not provided, the currently selected item will be accepted
+
+--- @class blink.cmp.CompletionListShowEvent
+--- @field items blink.cmp.CompletionItem[]
+--- @field context blink.cmp.Context
+
+--- @class blink.cmp.CompletionListHideEvent
+--- @field context blink.cmp.Context
+
+--- @class blink.cmp.CompletionListSelectEvent
+--- @field idx? number
+--- @field item? blink.cmp.CompletionItem
+--- @field items blink.cmp.CompletionItem[]
+--- @field context blink.cmp.Context
+
+--- @class blink.cmp.CompletionListAcceptEvent
+--- @field item blink.cmp.CompletionItem
+--- @field context blink.cmp.Context
+
+--- @type blink.cmp.CompletionList
+--- @diagnostic disable-next-line: missing-fields
+local list = {
+  select_emitter = require('blink.cmp.lib.event_emitter').new('select', 'BlinkCmpListSelect'),
+  accept_emitter = require('blink.cmp.lib.event_emitter').new('accept', 'BlinkCmpAccept'),
+  show_emitter = require('blink.cmp.lib.event_emitter').new('show', 'BlinkCmpShow'),
+  hide_emitter = require('blink.cmp.lib.event_emitter').new('hide', 'BlinkCmpHide'),
+  config = require('blink.cmp.config').completion.list,
+  context = nil,
+  items = {},
+  is_explicitly_selected = false,
+  preview_undo = nil,
+}
+
+---------- State ----------
+
+function list.show(context, items_by_source)
+  -- reset state for new context
+  local is_new_context = not list.context or list.context.id ~= context.id
+  if is_new_context then
+    list.preview_undo = nil
+    list.is_explicitly_selected = false
+  end
+
+  -- if the keyword changed, the list is no longer explicitly selected
+  local bounds_equal = list.context ~= nil
+    and list.context.bounds.start_col == context.bounds.start_col
+    and list.context.bounds.length == context.bounds.length
+  if not bounds_equal then list.is_explicitly_selected = false end
+
+  local previous_selected_item = list.get_selected_item()
+
+  -- update the context/list and emit
+  list.context = context
+  list.items = list.fuzzy(context, items_by_source)
+
+  if #list.items == 0 then
+    list.hide_emitter:emit({ context = context })
+  else
+    list.show_emitter:emit({ items = list.items, context = context })
+  end
+
+  -- maintain the selection if the user selected an item
+  local previous_item_idx = list.get_item_idx_in_list(previous_selected_item)
+  if list.is_explicitly_selected and previous_item_idx ~= nil and previous_item_idx <= 10 then
+    list.select(previous_item_idx, { auto_insert = false, undo_preview = false })
+
+  -- otherwise, use the default selection
+  else
+    list.select(
+      list.get_selection_mode(list.context).preselect and 1 or nil,
+      { auto_insert = false, undo_preview = false, is_explicit_selection = false }
+    )
+  end
+end
+
+function list.fuzzy(context, items_by_source)
+  local fuzzy = require('blink.cmp.fuzzy')
+  local filtered_items = fuzzy.fuzzy(
+    context.get_line(),
+    context.get_cursor()[2],
+    items_by_source,
+    require('blink.cmp.config').completion.keyword.range
+  )
+
+  -- apply the per source max_items
+  filtered_items = require('blink.cmp.sources.lib').apply_max_items_for_completions(context, filtered_items)
+
+  -- apply the global max_items
+  return require('blink.cmp.lib.utils').slice(filtered_items, 1, list.config.max_items)
+end
+
+function list.hide() list.hide_emitter:emit({ context = list.context }) end
+
+---------- Selection ----------
+
+function list.get_selected_item() return list.items[list.selected_item_idx] end
+
+function list.get_selection_mode(context)
+  assert(context ~= nil, 'Context must be set before getting selection mode')
+
+  local preselect = list.config.selection.preselect
+  if type(preselect) == 'function' then preselect = preselect(context) end
+  --- @cast preselect boolean
+
+  local auto_insert = list.config.selection.auto_insert
+  if type(auto_insert) == 'function' then auto_insert = auto_insert(context) end
+  --- @cast auto_insert boolean
+
+  return { preselect = preselect, auto_insert = auto_insert }
+end
+
+function list.get_item_idx_in_list(item)
+  if item == nil then return end
+  return require('blink.cmp.lib.utils').find_idx(list.items, function(i) return i.label == item.label end)
+end
+
+function list.select(idx, opts)
+  opts = opts or {}
+  local item = list.items[idx]
+
+  local auto_insert = opts.auto_insert
+  if auto_insert == nil then auto_insert = list.get_selection_mode(list.context).auto_insert end
+
+  require('blink.cmp.completion.trigger').suppress_events_for_callback(function()
+    if opts.undo_preview ~= false then list.undo_preview() end
+    if auto_insert and item ~= nil then list.apply_preview(item) end
+  end)
+
+  --- @diagnostic disable-next-line: assign-type-mismatch
+  list.is_explicitly_selected = opts.is_explicit_selection == nil and true or opts.is_explicit_selection
+  list.selected_item_idx = idx
+  list.select_emitter:emit({ idx = idx, item = item, items = list.items, context = list.context })
+end
+
+function list.select_next(opts)
+  if #list.items == 0 or list.context == nil then return end
+
+  -- haven't selected anything yet, select the first item
+  if list.selected_item_idx == nil then return list.select(1, opts) end
+
+  -- end of the list
+  if list.selected_item_idx == #list.items then
+    -- cycling around has been disabled, ignore
+    if not list.config.cycle.from_bottom then return end
+
+    -- preselect is not enabled, we go back to no selection
+    if not list.get_selection_mode(list.context).preselect then return list.select(nil, opts) end
+
+    -- otherwise, we cycle around
+    return list.select(1, opts)
+  end
+
+  -- typical case, select the next item
+  list.select(list.selected_item_idx + 1, opts)
+end
+
+function list.select_prev(opts)
+  if #list.items == 0 or list.context == nil then return end
+
+  -- haven't selected anything yet, select the last item
+  if list.selected_item_idx == nil then return list.select(#list.items, opts) end
+
+  -- start of the list
+  if list.selected_item_idx == 1 then
+    -- cycling around has been disabled, ignore
+    if not list.config.cycle.from_top then return end
+
+    -- auto_insert is enabled, we go back to no selection
+    if list.get_selection_mode(list.context).auto_insert then return list.select(nil, opts) end
+
+    -- otherwise, we cycle around
+    return list.select(#list.items, opts)
+  end
+
+  -- typical case, select the previous item
+  list.select(list.selected_item_idx - 1, opts)
+end
+
+---------- Preview ----------
+
+function list.undo_preview()
+  if list.preview_undo == nil then return end
+
+  require('blink.cmp.lib.text_edits').apply({ list.preview_undo.text_edit })
+  if list.preview_undo.cursor then
+    require('blink.cmp.completion.trigger.context').set_cursor(list.preview_undo.cursor)
+  end
+  list.preview_undo = nil
+end
+
+function list.apply_preview(item)
+  -- undo the previous preview if it exists
+  list.undo_preview()
+  -- apply the new preview
+  local undo_text_edit, undo_cursor = require('blink.cmp.completion.accept.preview')(item)
+  list.preview_undo = { text_edit = undo_text_edit, cursor = undo_cursor }
+end
+
+---------- Accept ----------
+
+function list.accept(opts)
+  opts = opts or {}
+  local item = list.items[opts.index or list.selected_item_idx]
+  if item == nil then return false end
+
+  list.undo_preview()
+  local accept = require('blink.cmp.completion.accept')
+  accept(list.context, item, function()
+    list.accept_emitter:emit({ item = item, context = list.context })
+    if opts.callback then opts.callback() end
+  end)
+  return true
+end
+
+return list