cmp: working through creating a cmp source

1 files changed, 136 insertions, 6 deletions

diff --git a/scratch/refresh.lua b/scratch/refresh.lua
index 8c34a9c..0777f65 100644
--- a/scratch/refresh.lua
+++ b/scratch/refresh.lua
@@ -2,10 +2,140 @@ local Window = require("99.window")
 Window.clear_active_popups()
 R("99")
 
-local function test()
-  Window = require("99.window")
-  Window.capture_input(function(input)
-    print(input)
-  end, {})
+-- Modern Neovim completion example using vim.lsp.completion and custom completions
+-- This is the newer API that replaced omnifunc
+
+-- Example 1: Using the built-in completion with a custom source
+local function setup_custom_completion()
+  -- Set up completion options
+  vim.opt.completeopt = { "menu", "menuone", "noselect" }
+
+  -- Create a custom completion function
+  -- This is called when user triggers completion (Ctrl-X Ctrl-U by default)
+  vim.api.nvim_buf_set_option(0, 'completefunc', 'v:lua.custom_complete')
 end
-test()
+
+-- Custom completion function
+-- Returns completion items when called
+function _G.custom_complete(findstart, base)
+  if findstart == 1 then
+    -- First call: return the column where completion starts
+    local line = vim.api.nvim_get_current_line()
+    local col = vim.api.nvim_win_get_cursor(0)[2]
+
+    -- Find start of the word
+    local start = col
+    while start > 0 and line:sub(start, start):match("[%w_]") do
+      start = start - 1
+    end
+
+    return start
+  else
+    -- Second call: return list of completions
+    -- 'base' is the text to complete
+    local completions = {
+      { word = "example_item", menu = "Example", kind = "Function" },
+      { word = "example_variable", menu = "Example", kind = "Variable" },
+      { word = "example_constant", menu = "Example", kind = "Constant" },
+    }
+
+    -- Filter completions based on what user typed
+    local matches = {}
+    for _, item in ipairs(completions) do
+      if item.word:find("^" .. base) then
+        table.insert(matches, item)
+      end
+    end
+
+    return matches
+  end
+end
+
+-- Example 2: Using nvim-cmp style manual completion
+-- This is the modern approach used by popular plugins
+local function create_completion_source()
+  return {
+    items = {
+      { label = "Window.clear_active_popups", kind = vim.lsp.protocol.CompletionItemKind.Method },
+      { label = "Window.capture_input", kind = vim.lsp.protocol.CompletionItemKind.Method },
+      { label = "Window.create_popup", kind = vim.lsp.protocol.CompletionItemKind.Method },
+      { label = "custom_item", kind = vim.lsp.protocol.CompletionItemKind.Variable },
+    },
+
+    complete = function(self, ctx)
+      local line = ctx.line
+      local cursor = ctx.cursor
+
+      -- Return filtered items based on context
+      return vim.tbl_filter(function(item)
+        return item.label:find(ctx.query or "", 1, true) ~= nil
+      end, self.items)
+    end
+  }
+end
+
+-- Example 3: Set up omnifunc (older API, but still works)
+-- This is triggered with Ctrl-X Ctrl-O
+function _G.my_omnifunc(findstart, base)
+  if findstart == 1 then
+    local line = vim.api.nvim_get_current_line()
+    local col = vim.api.nvim_win_get_cursor(0)[2]
+    return vim.fn.match(line:sub(1, col), [[\k*$]])
+  else
+    -- Return completion matches
+    return {
+      "Window.clear_active_popups()",
+      "Window.capture_input(callback, opts)",
+      "Window.create_floating_window()",
+      { word = "advanced_item", abbr = "adv", menu = "Custom", info = "Detailed info here" },
+    }
+  end
+end
+
+-- Set it up for the current buffer
+vim.api.nvim_buf_set_option(0, 'omnifunc', 'v:lua.my_omnifunc')
+
+-- Usage:
+-- Ctrl-X Ctrl-O to trigger omnifunc completion
+-- Ctrl-X Ctrl-U to trigger completefunc completion
+
+-- Example: Auto-trigger completion when typing '@' in 99-prompt buffer
+
+-- Custom completion function that provides context-aware items
+function _G.prompt_at_complete(findstart, base)
+  if findstart == 1 then
+    -- Find the start position (right after the '@')
+    local line = vim.api.nvim_get_current_line()
+    local col = vim.api.nvim_win_get_cursor(0)[2]
+
+    -- Find the '@' symbol
+    local start = col
+    while start > 0 and line:sub(start, start) ~= '@' do
+      start = start - 1
+    end
+
+    return start
+  else
+    -- Return completion items based on what comes after '@'
+    local completions = {
+      { word = "@file", menu = "Reference a file", kind = "File" },
+      { word = "@buffer", menu = "Reference a buffer", kind = "Reference" },
+      { word = "@selection", menu = "Reference current selection", kind = "Reference" },
+      { word = "@codebase", menu = "Search entire codebase", kind = "Keyword" },
+      { word = "@web", menu = "Search the web", kind = "Keyword" },
+    }
+
+    -- Filter based on what user has typed
+    local matches = {}
+    for _, item in ipairs(completions) do
+      if item.word:find("^@" .. vim.pesc(base), 1) then
+        table.insert(matches, item)
+      end
+    end
+
+    return matches
+  end
+end
+
+setup_custom_completion()
+