Extend API to get links to headline and org file (#768)

* feat(api): Extend API to get links

Considers id links, if org-id-link-to-org-use-id is set.
Creates ids on file and headline level if needed.

* chore: Remove stale require

* chore: tiny refactoring to align similar methods

Adapt the style of get_link_to_headline to new get_link_to_file
- avoid empty declaration of `id`
- move initialization of `path` close to it's usage

* refactor: make get_link member functions

Simplify the code by providing member functions on org.api.file and
org.api.headline.

* fix: handle unloaded buffers

---------

Co-authored-by: Sebastian Flügge <[email protected]>

lua/orgmode/api/file.lua

@@ -1,5 +1,7 @@
 ---@diagnostic disable: invisible
 local OrgHeadline = require('orgmode.api.headline')
+local Hyperlinks = require('orgmode.org.hyperlinks')
+local org = require('orgmode')
 
 ---@class OrgApiFile
 ---@field category string current file category name. By default it's only filename without extension unless defined differently via #+CATEGORY directive
@@ -92,4 +94,30 @@ function OrgFile:get_closest_headline(cursor)
   return nil
 end
 
+--- Get a link destination as string
+---
+--- Depending if org_id_link_to_org_use_id is set the format is
+---
+--- id:<uuid>::*title and the id is created if not existing
+--- or
+--- file:<filepath>::*title
+---
+--- The result is meant to be used as link_location for OrgApi.insert_link.
+--- @return string
+function OrgFile:get_link()
+  local filename = self.filename
+  local bufnr = vim.fn.bufnr(filename)
+
+  if bufnr == -1 or not vim.api.nvim_buf_is_loaded(bufnr) then
+    -- do remote edit
+    return org.files
+      :update_file(filename, function(file)
+        return Hyperlinks.get_link_to_file(file)
+      end)
+      :wait()
+  end
+
+  return Hyperlinks.get_link_to_file(self._file)
+end
+
 return OrgFile

lua/orgmode/api/headline.lua

@@ -3,6 +3,7 @@ local PriorityState = require('orgmode.objects.priority_state')
 local Date = require('orgmode.objects.date')
 local Calendar = require('orgmode.objects.calendar')
 local Promise = require('orgmode.utils.promise')
+local Hyperlinks = require('orgmode.org.hyperlinks')
 local org = require('orgmode')
 
 ---@class OrgApiHeadline
@@ -259,4 +260,30 @@ function OrgHeadline:_do_action(action)
   end)
 end
 
+--- Get a link destination as string
+---
+--- Depending if org_id_link_to_org_use_id is set the format is
+---
+--- id:<uuid>::*title and the id is created if not existing
+--- or
+--- file:<filepath>::*title
+---
+--- The result is meant to be used as link_location for OrgApi.insert_link.
+--- @return string
+function OrgHeadline:get_link()
+  local filename = self.file.filename
+  local bufnr = vim.fn.bufnr(filename)
+
+  if bufnr == -1 or not vim.api.nvim_buf_is_loaded(bufnr) then
+    -- do remote edit
+    return org.files
+      :update_file(filename, function(_)
+        return Hyperlinks.get_link_to_headline(self._section)
+      end)
+      :wait()
+  end
+
+  return Hyperlinks.get_link_to_headline(self._section)
+end
+
 return OrgHeadline

lua/orgmode/api/init.lua

@@ -2,7 +2,6 @@
 local OrgFile = require('orgmode.api.file')
 local OrgHeadline = require('orgmode.api.headline')
 local Hyperlinks = require('orgmode.org.hyperlinks')
-local Link = require('orgmode.org.hyperlinks.link')
 local orgmode = require('orgmode')
 
 ---@class OrgApiRefileOpts
@@ -102,6 +101,12 @@ function OrgApi.refile(opts)
 end
 
 --- Insert a link to a given location at the current cursor position
+---
+--- The expected format is
+--- <protocol>:<location>::<in_file_location>
+---
+--- If <in_file_location> is *<headline>, <headline> is used as prefilled description for the link.
+--- If <protocol> is id, this format can also be used to pass a prefilled description.
 --- @param link_location string
 --- @return boolean
 function OrgApi.insert_link(link_location)

lua/orgmode/files/file.lua

@@ -669,6 +669,7 @@ end
 
 memoize('get_category')
 --- Get the category name for this file
+--- If no category is set, the filename without extension is returned
 --- @return string
 function OrgFile:get_category()
   local category = self:_get_directive('category')
@@ -679,6 +680,19 @@ function OrgFile:get_category()
   return vim.fn.fnamemodify(self.filename, ':t:r') or ''
 end
 
+memoize('get_title')
+--- Get the title for this file
+--- If no title is set, the filename without extension is returned
+--- @return string
+function OrgFile:get_title()
+  local title = self:_get_directive('title')
+  if title then
+    return title
+  end
+
+  return vim.fn.fnamemodify(self.filename, ':t:r') or ''
+end
+
 memoize('get_opened_unfinished_headlines')
 ---@return OrgHeadline[]
 function OrgFile:get_opened_unfinished_headlines()
@@ -729,6 +743,18 @@ function OrgFile:get_directive(directive_name)
   return self:_get_directive(directive_name)
 end
 
+--- Get headline id or create a new one if it doesn't exist
+--- @return string
+function OrgFile:id_get_or_create()
+  local id = self:get_property('id')
+  if id then
+    return id
+  end
+  local org_id = require('orgmode.org.id').new()
+  self:set_property('ID', org_id)
+  return org_id
+end
+
 ---@private
 ---@return string | nil
 function OrgFile:_get_directive(directive_name)

lua/orgmode/org/hyperlinks/init.lua

@@ -174,16 +174,32 @@ end
 ---@param headline OrgHeadline
 ---@param path? string
 function Hyperlinks.get_link_to_headline(headline, path)
-  path = path or utils.current_file_path()
   local title = headline:get_title()
-  local id
+
   if config.org_id_link_to_org_use_id then
-    id = headline:id_get_or_create()
+    local id = headline:id_get_or_create()
+    if id then
+      return ('id:%s::*%s'):format(id, title)
+    end
   end
 
-  if config.org_id_link_to_org_use_id and id then
-    return ('id:%s::*%s'):format(id, title)
+  path = path or utils.current_file_path()
+  return ('file:%s::*%s'):format(path, title)
+end
+
+---@param file OrgFile
+---@param path? string
+function Hyperlinks.get_link_to_file(file, path)
+  local title = file:get_title()
+
+  if config.org_id_link_to_org_use_id then
+    local id = file:id_get_or_create()
+    if id then
+      return ('id:%s::*%s'):format(id, title)
+    end
   end
+
+  path = path or file.filename
   return ('file:%s::*%s'):format(path, title)
 end