From 6e6a09e32f9653d6754842785ffa4d9d5730bb71 Mon Sep 17 00:00:00 2001
From: jdhao <jdhao@hotmail.com>
Date: Sat, 7 Jun 2025 19:12:01 +0200
Subject: [PATCH] Add support for markdown ref-style link (#415)

---
 after/ftplugin/markdown.lua   | 107 ++++++++++++++++++++++++++++++++++
 my_snippets/markdown.snippets |   4 ++
 2 files changed, 111 insertions(+)
 create mode 100644 after/ftplugin/markdown.lua

diff --git a/after/ftplugin/markdown.lua b/after/ftplugin/markdown.lua
new file mode 100644
index 0000000..662bbea
--- /dev/null
+++ b/after/ftplugin/markdown.lua
@@ -0,0 +1,107 @@
+local function add_reference_at_end(label, url, title)
+  vim.schedule(function()
+    local bufnr = vim.api.nvim_get_current_buf()
+    local line_count = vim.api.nvim_buf_line_count(bufnr)
+
+    -- Prepare reference definition
+    local ref_def = "[" .. label .. "]: " .. url
+    if title and title ~= "" then
+      ref_def = ref_def .. ' "' .. title .. '"'
+    end
+
+    -- Check if references section exists
+    local buffer_lines = vim.api.nvim_buf_get_lines(bufnr, 0, -1, false)
+
+    local has_ref_section = false
+    for _, line in ipairs(buffer_lines) do
+      if line:match("^%s*<!%-%-.*[Rr]eferences.*%-%->[%s]*$") then
+        has_ref_section = true
+        break
+      end
+    end
+
+    local lines_to_add = {}
+    -- Add references header if it doesn't exist
+    if not has_ref_section then
+      if #lines_to_add == 0 then
+        table.insert(lines_to_add, "")
+      end
+      table.insert(lines_to_add, "<!-- References -->")
+    end
+
+    table.insert(lines_to_add, ref_def)
+
+    -- Insert at buffer end
+    vim.api.nvim_buf_set_lines(bufnr, line_count, line_count, false, lines_to_add)
+  end)
+end
+
+local function get_ref_link_labels()
+  local labels = {}
+  local seen = {} -- To avoid duplicates
+  local lines = vim.api.nvim_buf_get_lines(0, 0, -1, false)
+
+  for _, line in ipairs(lines) do
+    -- Pattern explanation:
+    -- %[.-%] matches [link text] (non-greedy)
+    -- %[(.-)%] matches [label] and captures the label content
+    local start_pos = 1
+    while start_pos <= #line do
+      local match_start, match_end, label = string.find(line, "%[.-%]%[(.-)%]", start_pos)
+      if not match_start then
+        break
+      end
+
+      -- Only add unique labels
+      if label and label ~= "" and not seen[label] then
+        table.insert(labels, label)
+        seen[label] = true
+      end
+
+      start_pos = match_end + 1
+    end
+  end
+
+  return labels
+end
+
+local function count_consecutive_spaces(str)
+  -- Remove leading spaces first
+  local trimmed = str:match("^%s*(.*)")
+  local count = 0
+
+  -- Count each sequence of one or more consecutive spaces
+  for spaces in trimmed:gmatch("%s+") do
+    count = count + 1
+  end
+  return count
+end
+
+vim.api.nvim_buf_create_user_command(0, "AddRef", function(opts)
+  local args = vim.split(opts.args, " ", { trimempty = true })
+
+  if #args < 2 then
+    vim.print("Usage: :AddRef <label> <url>")
+    return
+  end
+
+  local label = args[1]
+  local url = args[2]
+
+  add_reference_at_end(label, url, "")
+end, {
+  desc = "Add reference link at buffer end",
+  nargs = "+",
+  complete = function(arg_lead, cmdline, curpos)
+    vim.print(string.format("arg_lead: '%s', cmdline: '%s', curpos: %d", arg_lead, cmdline, curpos))
+
+    -- only complete the first argument
+    if count_consecutive_spaces(cmdline) > 1 then
+      -- we are now starting the second argument, so no completion anymore
+      return {}
+    end
+
+    local ref_link_labels = get_ref_link_labels()
+    return ref_link_labels
+  end,
+})
diff --git a/my_snippets/markdown.snippets b/my_snippets/markdown.snippets
index e00f538..d218cb0 100644
--- a/my_snippets/markdown.snippets
+++ b/my_snippets/markdown.snippets
@@ -54,6 +54,10 @@ snippet link "Markdown links"
 [$1]($2)$0
 endsnippet
 
+snippet rlink "Markdown ref link"
+[${1:link_text}][${2:label}]
+endsnippet
+
 post_jump "gen_header(snip)"
 snippet "h([1-6])" "Markdown header" br
 `!p snip.rv = match.group(1)`