1 files changed, 105 insertions, 0 deletions
diff --git a/start/cmp/lua/cmp/context.lua b/start/cmp/lua/cmp/context.lua
new file mode 100644
index 0000000..6188259
--- /dev/null
+++ b/start/cmp/lua/cmp/context.lua
@@ -0,0 +1,105 @@
+local misc = require('cmp.utils.misc')
+local pattern = require('cmp.utils.pattern')
+local types = require('cmp.types')
+local cache = require('cmp.utils.cache')
+local api = require('cmp.utils.api')
+
+---@class cmp.Context
+---@field public id string
+---@field public cache cmp.Cache
+---@field public prev_context cmp.Context
+---@field public option cmp.ContextOption
+---@field public filetype string
+---@field public time number
+---@field public bufnr number
+---@field public cursor vim.Position|lsp.Position
+---@field public cursor_line string
+---@field public cursor_after_line string
+---@field public cursor_before_line string
+local context = {}
+
+---Create new empty context
+---@return cmp.Context
+context.empty = function()
+  local ctx = context.new({}) -- dirty hack to prevent recursive call `context.empty`.
+  ctx.bufnr = -1
+  ctx.input = ''
+  ctx.cursor = {}
+  ctx.cursor.row = -1
+  ctx.cursor.col = -1
+  return ctx
+end
+
+---Create new context
+---@param prev_context cmp.Context
+---@param option cmp.ContextOption
+---@return cmp.Context
+context.new = function(prev_context, option)
+  option = option or {}
+
+  local self = setmetatable({}, { __index = context })
+  self.id = misc.id('cmp.context.new')
+  self.cache = cache.new()
+  self.prev_context = prev_context or context.empty()
+  self.option = option or { reason = types.cmp.ContextReason.None }
+  self.filetype = vim.api.nvim_buf_get_option(0, 'filetype')
+  self.time = vim.loop.now()
+  self.bufnr = vim.api.nvim_get_current_buf()
+
+  local cursor = api.get_cursor()
+  self.cursor_line = api.get_current_line()
+  self.cursor = {}
+  self.cursor.row = cursor[1]
+  self.cursor.col = cursor[2] + 1
+  self.cursor.line = self.cursor.row - 1
+  self.cursor.character = misc.to_utfindex(self.cursor_line, self.cursor.col)
+  self.cursor_before_line = string.sub(self.cursor_line, 1, self.cursor.col - 1)
+  self.cursor_after_line = string.sub(self.cursor_line, self.cursor.col)
+  return self
+end
+
+---Return context creation reason.
+---@return cmp.ContextReason
+context.get_reason = function(self)
+  return self.option.reason
+end
+
+---Get keyword pattern offset
+---@return number|nil
+context.get_offset = function(self, keyword_pattern)
+  return self.cache:ensure({ 'get_offset', keyword_pattern, self.cursor_before_line }, function()
+    return pattern.offset(keyword_pattern .. '\\m$', self.cursor_before_line) or self.cursor.col
+  end)
+end
+
+---Return if this context is changed from previous context or not.
+---@return boolean
+context.changed = function(self, ctx)
+  local curr = self
+
+  if curr.bufnr ~= ctx.bufnr then
+    return true
+  end
+  if curr.cursor.row ~= ctx.cursor.row then
+    return true
+  end
+  if curr.cursor.col ~= ctx.cursor.col then
+    return true
+  end
+  if curr:get_reason() == types.cmp.ContextReason.Manual then
+    return true
+  end
+
+  return false
+end
+
+---Shallow clone
+context.clone = function(self)
+  local cloned = {}
+  for k, v in pairs(self) do
+    cloned[k] = v
+  end
+  return cloned
+end
+
+return context