refactor: port metadata feature to lua

autoload/corpus.vim

@@ -13,24 +13,9 @@ let s:chooser_window=v:null
 
 let s:preview_buffer=v:null
 let s:preview_window=v:null
-
-" When opening a new file in a Corpus-managed location, pre-populate it
-" with metadata of the form:
-"
-"   ---
-"   title: Title based on file name
-"   tags: wiki
-"   ---
-"
-" or:
-"
-"   ---
-"   title: Title based on file name
-"   ---
-"
 function! corpus#buf_new_file() abort
   let l:file=v:lua.corpus.normalize('<afile>')
-  call corpus#update_metadata(l:file)
+  call v:lua.corpus.metadata.update(l:file)
   let b:corpus_new_file=1
 endfunction
 
@@ -48,7 +33,7 @@ endfunction
 function! corpus#buf_write_pre() abort
   let l:file=v:lua.corpus.normalize('<afile>')
   call corpus#update_references(l:file)
-  call corpus#update_metadata(l:file)
+  call v:lua.corpus.metadata.update(l:file)
 endfunction
 
 " Minimal subset of:
@@ -129,57 +114,6 @@ function! corpus#extract_reference_links(line) abort
   return l:reference_links
 endfunction
 
-let s:metadata_key_value_pattern='\v^\s*(\w+)\s*:\s*(\S.{-})\s*$'
-
-" Returns raw metadata as a list of strings; eg:
-"
-"   ['tags: wiki', 'title: foo']
-"
-" If there is no valid metadata, an empty list is returned.
-"
-" If there are blank lines in the metadata, they are included in the list.
-function! corpus#get_metadata_raw() abort
-  if match(getline(1), '\v^---\s*$') != -1
-    let l:metadata=[]
-    for l:i in range(2, line('$'))
-      let l:line=getline(l:i)
-      if match(l:line, '\v^\s*$') != -1
-        call add(l:metadata, '')
-        continue
-      elseif match(l:line, '\v^---\s*$') != -1
-        return l:metadata
-      endif
-      let l:match=matchlist(l:line, s:metadata_key_value_pattern)
-      if len(l:match) == 0
-        return []
-      endif
-      call add(l:metadata, (l:match[0]))
-    endfor
-  endif
-  return []
-endfunction
-
-" Returns metadata as a dictionary; eg:
-"
-"   {'tags': 'wiki', 'title': 'foo'}
-"
-" If there is no valid metadata, an empty dictionary is returned.
-function! corpus#get_metadata() abort
-  let l:raw=corpus#get_metadata_raw()
-  if len(l:raw)
-    let l:metadata={}
-    for l:line in l:raw
-      let l:match=matchlist(l:line, s:metadata_key_value_pattern)
-      if len(l:match)
-        let l:metadata[l:match[1]]=l:match[2]
-      endif
-    endfor
-    return l:metadata
-  else
-    return {}
-  endif
-endfunction
-
 function! corpus#goto(mode) abort
   if a:mode == 'v'
     " Visual mode.
@@ -315,34 +249,6 @@ function! corpus#goto(mode) abort
   endif
 endfunction
 
-function! corpus#set_metadata(metadata) abort
-  " Remove old metadata, if present.
-  let l:raw=corpus#get_metadata_raw()
-  if (len(l:raw))
-    " +2 lines for the '---' delimiters.
-    call deletebufline('', 1, len(l:raw) + 2)
-  endif
-
-  " Format new metadata.
-  let l:lines=['---']
-  let l:keys=keys(a:metadata)
-  for l:key in l:keys
-    call add(l:lines, l:key . ': ' . a:metadata[l:key])
-  endfor
-  call add(l:lines, '---')
-
-  " Prepend new metadata.
-  call append(0, l:lines)
-
-  " Make sure there is at least one blank line after metadata.
-  " +2 lines for the '---' delimiters.
-  " +1 more to see next line.
-  let l:next=len(l:keys) + 2 + 1
-  if match(getline(l:next), '\v^\s*$') == -1
-    call append(l:next - 1, '')
-  endif
-endfunction
-
 function! corpus#test() abort
   let v:errors=[]
 
@@ -373,7 +279,7 @@ function! corpus#update_references(file) abort
   endif
 
   " Skip over metadata.
-  let l:raw=corpus#get_metadata_raw()
+  let l:raw=v:lua.corpus.metadata.raw()
   if len(l:raw)
     let l:start=len(l:raw) + 2 + 1
   else
@@ -455,31 +361,6 @@ function! corpus#update_references(file) abort
   endfor
 endfunction
 
-function! corpus#update_metadata(file) abort
-  let l:config=v:lua.corpus.config_for_file(a:file)
-  if !get(l:config, 'autotitle', 0) && !has_key(l:config, 'tags')
-    return
-  endif
-
-  let l:metadata=corpus#get_metadata()
-
-  if get(l:config, 'autotitle', 0)
-    let l:title=v:lua.corpus.title_for_file(a:file)
-    let l:metadata.title=l:title
-  endif
-
-  if has_key(l:config, 'tags')
-    let l:tags=split(get(l:metadata, 'tags', ''))
-    for l:tag in l:config.tags
-      if index(l:tags, l:tag) == -1
-        call add(l:tags, l:tag)
-      endif
-    endfor
-    let l:metadata.tags=join(l:tags)
-  endif
-  call corpus#set_metadata(l:metadata)
-endfunction
-
 function! corpus#complete(arglead, cmdline, cursor_pos) abort
   return v:lua.corpus.complete(a:arglead, a:cmdline, a:cursor_pos)
 endfunction

lua/corpus/init.lua

@@ -53,6 +53,7 @@ end
 -- TODO make most of these private (really only want them public for testing
 -- during development)
 corpus = {
+  metadata = require'corpus.metadata',
   choose = function(selection)
     selection = vim.trim(selection)
     local file = corpus.get_selected_file()

lua/corpus/metadata.lua

@@ -0,0 +1,182 @@
+-- Copyright 2015-present Greg Hurrell. All rights reserved.
+-- Licensed under the terms of the MIT license.
+
+--- TODO: would it be worth it to embed
+--- https://github.com/exosite/lua-yaml/blob/master/yaml.lua?
+local M = {}
+
+---YAML Key-value pair pattern
+local kv_pattern = [[\v^\s*(\w+)\s*:\s*(\S.{-})\s*$]]
+
+---Given a list of key value pairs, update key with value
+-- @param key string
+-- @param value string
+local set_kv_list = function (list, key, value)
+  for _, kv in ipairs(list) do
+    if kv[1] == key then kv[2] = value end
+  end
+end
+
+---Get value from key-value pair list
+---@param list any
+---@return string?
+local get_kv_list = function(list, key)
+  for _, kv in ipairs(list) do
+    if kv[1] == key then return kv[2] end
+  end
+end
+
+---Check whether current line is the start of metadata block or not
+---@param line string
+---@return boolean: true if it's the start/end of metadata block
+local is_block_delim = function(line)
+  return vim.fn.match(line, [[\v^---\s*$]]) ~= -1
+end
+
+---Convert Lua value to Yaml value
+---@return string
+local yaml_value = (function ()
+  local convert = {
+    ['boolean'] = function (lua_value)
+      return vim.inspect(lua_value) -- yah maybe overkill :D
+    end,
+    ['table'] = function(lua_value)
+      if vim.tbl_islist(lua_value) then
+       return ("[%s]"):format(table.concat(lua_value, ","))
+      end
+    end
+  }
+  return function (value)
+    return convert(type(value))(value)
+  end
+end)
+
+---Wrapper function for vim.fn.match for convenience.
+---@param line string: line to match against
+---@param pattern string: regex
+---@return boolean: true if match
+local match = function(line, pattern)
+  return vim.fn.match(line, pattern) ~= -1
+end
+
+--- Read current buffer and dump yaml block lines into a list
+---@return table: list of string
+M.raw = function()
+  if is_block_delim(vim.fn.getline(1)) then
+    local res = {}
+    local range = vim.fn.range(2, vim.fn.line('$'))
+
+    for _, i in ipairs(range) do
+
+      local line = vim.fn.getline(i)
+      if match(line, [[\v^\s*$]]) then
+        res[#res+1] = ''
+      elseif is_block_delim(line) then
+        return res
+      end
+
+      local match = vim.fn.matchlist(line, kv_pattern)
+      if #match == 0 then
+        return {}
+      end
+      res[#res+1] = match[1]
+
+    end
+  end
+
+  return {}
+end
+
+--- Read current buffer and returns a metadata as list of key values pairs
+---@return table: eg: { {"title", "README"}, {"tags", "foo"} }
+M.decode = function()
+  local res = {}
+  local raw = M.raw()
+  if #raw == 0 then return {} end
+
+  for _, line in ipairs(raw) do
+    local match = vim.fn.matchlist(line,kv_pattern)
+    if #match ~= 0 then
+      res[#res+1] = { match[2], match[3]  }
+    end
+  end
+
+  return res
+end
+
+--- Encode lua table into yaml string
+---@param metadata table: list of key-values pairs
+---@return table: YAML string
+M.encode = function(metadata)
+  local res = {"---"}
+  for _, kv in ipairs(metadata) do
+    local key, value = kv[1], kv[2]
+    if type(value) ~= "string" then
+      value = yaml_value(value)
+    end
+    table.insert(res, ("%s: %s"):format(key, value))
+  end
+  table.insert(res, "---")
+  return res
+end
+
+---Update title to match the filename (TODO: or the other way around)
+---@param config table: file or user configuration
+---@param path string: file path
+---@param metadata table: file metadata
+M.__update_title = function(config, path, metadata)
+  --- TODO: Check if title is different from file name
+  --- and if so update filename not fontmatter.
+  if config.autotitle ~= 1 then return end
+  local title = corpus.title_for_file(path)
+  if #metadata ~= 0 then
+    set_kv_list(metadata, "title", title)
+  else
+    metadata[#metadata+1] = {"title", title}
+  end
+end
+
+
+---Update tags to contain user or configuration tags
+---@param config table: file or user configuration
+---@param path string: file path
+---@param metadata table: file metadata
+M.__update_tags = function(config, path, metadata)
+  if not config.tags then return end
+  local tags = vim.split(get_kv_list(metadata, "tags") or "", " ")
+
+  for _, tag in ipairs(config.tags) do
+    if vim.fn.index(tags, tag) == -1 then
+      tags[#tags+1] = tag
+    end
+  end
+
+  set_kv_list(metadata, "tags", tags)
+end
+
+M.__update_buf = function(metadata)
+  local yaml = M.encode(metadata)
+  local raw = M.raw()
+
+  if #raw ~= 0 then
+    vim.fn.deletebufline('', 1, #raw +2)
+  end
+
+  vim.fn.append(0, yaml)
+
+end
+
+---Main function in metadata module. It update title, tags and metadata
+---@param path string: filepath
+M.update = function(path)
+  local config = corpus.config_for_file(path)
+  if config.autotitle ~= 1 and not config.tags then return end
+
+  local metadata = M.decode()
+
+  M.__update_title(config, path, metadata)
+  M.__update_tags(config, path, metadata)
+  M.__update_buf(metadata)
+end
+
+return M