builtins/completion: add nvim-snippets source (#201)

doc/BUILTINS.md

@@ -219,6 +219,21 @@ local sources = { null_ls.builtins.completion.luasnip }
 
 - Registering this source will show available snippets in the completion list, but luasnip is in charge of expanding them. Consult [luasnip's documentation](https://github.com/L3MON4D3/LuaSnip#keymaps) to set up keymaps for expansion and jumping.
 
+### [nvim_snippets](https://github.com/garymjr/nvim-snippets)
+
+Snippets managed by nvim-snippets.
+
+#### Usage
+
+```lua
+local sources = { null_ls.builtins.completion.nvim_snippets }
+```
+
+#### Defaults
+
+- Filetypes: `{}`
+- Method: `completion`
+
 ### spell
 
 Spell suggestions completion source.

doc/builtins.json

@@ -57,6 +57,9 @@
     "luasnip": {
       "filetypes": []
     },
+    "nvim_snippets": {
+      "filetypes": []
+    },
     "spell": {
       "filetypes": []
     },

lua/null-ls/builtins/_meta/completion.lua

@@ -4,6 +4,9 @@ return {
   luasnip = {
     filetypes = {}
   },
+  nvim_snippets = {
+    filetypes = {}
+  },
   spell = {
     filetypes = {}
   },

lua/null-ls/builtins/completion/nvim_snippets.lua

@@ -0,0 +1,72 @@
+local h = require("null-ls.helpers")
+local methods = require("null-ls.methods")
+
+local COMPLETION = methods.internal.COMPLETION
+
+-- based on pattern from cmp-luasnip
+local pattern = "\\%([^[:alnum:][:blank:]]\\+\\|\\w\\+\\)"
+local regex = vim.regex([[\%(]] .. pattern .. [[\)\m$]])
+
+local function nvim_snippet_exists()
+    local status, _ = pcall(require, "snippets")
+
+    return status
+end
+
+local function get_loaded_snippets()
+    return require("snippets").get_loaded_snippets()
+end
+
+return h.make_builtin({
+    name = "nvim_snippets",
+    can_run = nvim_snippet_exists,
+    condition = nvim_snippet_exists,
+    runtime_condition = h.cache.by_bufnr(function()
+        return not vim.tbl_isempty(get_loaded_snippets())
+    end),
+    meta = {
+        url = "https://github.com/garymjr/nvim-snippets",
+        description = "Snippets managed by nvim-snippets.",
+    },
+    method = COMPLETION,
+    filetypes = {},
+    generator = {
+        --- @param params NullLsParams
+        --- @param done fun()
+        fn = function(params, done)
+            local line_to_cursor = params.content[params.row]:sub(1, params.col)
+            local start_col = regex:match_str(line_to_cursor)
+
+            if nil == start_col then
+                done({ { items = {}, isIncomplete = true } })
+                return
+            end
+
+            local items = {}
+            local snippets = get_loaded_snippets()
+            for _, item in pairs(snippets) do
+                if vim.startswith(item.prefix, line_to_cursor:sub(start_col)) then
+                    local insertText = (type(item.body) == "table") and table.concat(item.body, "\n") or item.body
+                    local textEdit = {
+                        range = {
+                            start = { line = params.row - 1, character = start_col },
+                            ["end"] = { line = params.row - 1, character = params.col - start_col },
+                        },
+                        newText = insertText,
+                    }
+
+                    items[#items + 1] = {
+                        label = item.prefix,
+                        kind = vim.lsp.protocol.CompletionItemKind.Snippet,
+                        insertTextFormat = vim.lsp.protocol.InsertTextFormat.Snippet,
+                        detail = item.description,
+                        insertText = insertText,
+                        textEdit = textEdit,
+                    }
+                end
+            end
+            done({ { items = items, isIncomplete = #items == 0 } })
+        end,
+        async = true,
+    },
+})