1 files changed, 163 insertions, 0 deletions
diff --git a/lua/lvim/core/luasnip.lua b/lua/lvim/core/luasnip.lua
new file mode 100644
index 00000000..10782d0e
--- /dev/null
+++ b/lua/lvim/core/luasnip.lua
@@ -0,0 +1,163 @@
+local M = {}
+
+-- see luasnip/util/types.lua
+local types = {
+  textNode = 1,
+  insertNode = 2,
+  functionNode = 3,
+  snippetNode = 4,
+  choiceNode = 5,
+  dynamicNode = 6,
+  snippet = 7,
+  exitNode = 8,
+  restoreNode = 9,
+  node_types = { 1, 2, 3, 4, 5, 6, 7, 8, 9 },
+}
+
+function M.config()
+  lvim.builtin.luasnip = {
+    sources = {
+      friendly_snippets = true,
+    },
+    config = {
+      history = false,
+      updateevents = "TextChanged,TextChangedI",
+      ext_opts = {
+        -- Will be populated within config function
+      },
+    },
+    ext_opts = {
+      -- Show virtual text to signal when you are inside an sippets
+      [types.insertNode] = {
+        active = {
+          virt_text = { { "<-- snip insert", "BufferInactiveIndex" } },
+        },
+      },
+      -- Helps to notice when you are within a choice node
+      [types.choiceNode] = {
+        active = {
+          virt_text = { { "<-- choice", "BufferInactiveIndex" } },
+        },
+      },
+    },
+  }
+end
+
+function M.setup()
+  local utils = require "lvim.utils"
+  local paths = {}
+  if lvim.builtin.luasnip.sources.friendly_snippets then
+    paths[#paths + 1] = utils.join_paths(get_runtime_dir(), "site", "pack", "packer", "start", "friendly-snippets")
+  end
+
+  local user_snippets = utils.join_paths(get_config_dir(), "snippets")
+  if utils.is_directory(user_snippets) then
+    paths[#paths + 1] = user_snippets
+  end
+
+  local luasnip = require "luasnip"
+  luasnip.config.set_config(lvim.builtin.luasnip.config)
+
+  -- When no paths are provided, luasnip will search in the runtimepath
+  require("luasnip.loaders.from_lua").lazy_load()
+  require("luasnip.loaders.from_vscode").lazy_load { paths = paths }
+  require("luasnip.loaders.from_snipmate").lazy_load()
+end
+
+---when inside a snippet, seeks to the nearest luasnip field if possible, and checks if it is jumpable
+---@param dir number 1 for forward, -1 for backward; defaults to 1
+---@return boolean true if a jumpable luasnip field is found while inside a snippet
+local function jumpable(dir)
+  local luasnip_ok, luasnip = pcall(require, "luasnip")
+  if not luasnip_ok then
+    return false
+  end
+
+  local win_get_cursor = vim.api.nvim_win_get_cursor
+  local get_current_buf = vim.api.nvim_get_current_buf
+
+  ---sets the current buffer's luasnip to the one nearest the cursor
+  ---@return boolean true if a node is found, false otherwise
+  local function seek_luasnip_cursor_node()
+    -- TODO(kylo252): upstream this
+    -- for outdated versions of luasnip
+    if not luasnip.session.current_nodes then
+      return false
+    end
+
+    local node = luasnip.session.current_nodes[get_current_buf()]
+    if not node then
+      return false
+    end
+
+    local snippet = node.parent.snippet
+    local exit_node = snippet.insert_nodes[0]
+
+    local pos = win_get_cursor(0)
+    pos[1] = pos[1] - 1
+
+    -- exit early if we're past the exit node
+    if exit_node then
+      local exit_pos_end = exit_node.mark:pos_end()
+      if (pos[1] > exit_pos_end[1]) or (pos[1] == exit_pos_end[1] and pos[2] > exit_pos_end[2]) then
+        snippet:remove_from_jumplist()
+        luasnip.session.current_nodes[get_current_buf()] = nil
+
+        return false
+      end
+    end
+
+    node = snippet.inner_first:jump_into(1, true)
+    while node ~= nil and node.next ~= nil and node ~= snippet do
+      local n_next = node.next
+      local next_pos = n_next and n_next.mark:pos_begin()
+      local candidate = n_next ~= snippet and next_pos and (pos[1] < next_pos[1])
+          or (pos[1] == next_pos[1] and pos[2] < next_pos[2])
+
+      -- Past unmarked exit node, exit early
+      if n_next == nil or n_next == snippet.next then
+        snippet:remove_from_jumplist()
+        luasnip.session.current_nodes[get_current_buf()] = nil
+
+        return false
+      end
+
+      if candidate then
+        luasnip.session.current_nodes[get_current_buf()] = node
+        return true
+      end
+
+      local ok
+      ok, node = pcall(node.jump_from, node, 1, true) -- no_move until last stop
+      if not ok then
+        snippet:remove_from_jumplist()
+        luasnip.session.current_nodes[get_current_buf()] = nil
+
+        return false
+      end
+    end
+
+    -- No candidate, but have an exit node
+    if exit_node then
+      -- to jump to the exit node, seek to snippet
+      luasnip.session.current_nodes[get_current_buf()] = snippet
+      return true
+    end
+
+    -- No exit node, exit from snippet
+    snippet:remove_from_jumplist()
+    luasnip.session.current_nodes[get_current_buf()] = nil
+    return false
+  end
+
+  if dir == -1 then
+    return luasnip.in_snippet() and luasnip.jumpable(-1) else
+    return luasnip.in_snippet() and seek_luasnip_cursor_node() and luasnip.jumpable(1)
+  end
+end
+
+M.methods = {}
+
+M.methods.jumpable = jumpable
+
+return M