Add anchor duplicate checking before creation

lua/zettelkasten/anchor.lua

@@ -2,16 +2,23 @@ local A = {}
 
 local o = require 'zettelkasten.options'
 
+local function deduplicate(anchor, anchorfct)
+    while A.is_duplicate(anchor, anchorfct) do anchor = anchor - 1 end
+    return anchor
+end
+
 -- Return a valid zettelkasten anchor,
 -- composed of yymmddHHMM.
 --
 -- date can be passed in as a table containing a year, a month, a day, an hour,
 -- and a minute key. Returns nil if the date passed in is invalid.
 -- If no date is passed in, returns Zettel anchor for current moment.
-function A.create(date)
+function A.create(date, anchorfct)
     local timestamp
     if pcall(function() timestamp = os.time(date) end) then
-        return os.date('%y%m%d%H%M', timestamp)
+        local anchor = os.date('%y%m%d%H%M', timestamp)
+        if anchorfct then anchor = deduplicate(anchor, anchorfct) end
+        return tostring(anchor)
     else
         return nil
     end
@@ -37,4 +44,21 @@ function A.extract(input, regex)
     return input:match(regex)
 end
 
+-- Returns a set of all anchors created by the function passed in
+-- (if argument is set) or all anchors currently in zettel root dir
+-- (if no argument passed).
+function A.list(anchor_function)
+    if not anchor_function then return {} end
+    return anchor_function()
+end
+
+-- Returns true if anchor passed in already exists, false otherwise.
+-- Takes an optional set of anchors to compare against, will
+-- compare against all anchors in zettel root dir otherwise.
+function A.is_duplicate(anchor, anchor_function)
+    local all_anchors = A.list(anchor_function)
+    if all_anchors[anchor] ~= nil then return true end
+    return false
+end
+
 return A

lua/zettelkasten/anchor_spec.lua

@@ -14,6 +14,22 @@ describe("create", function()
 
     it("should return nil if argument passed in is invalid",
        function() assert.is_nil(A.create("My grandmother is lovely.")) end)
+
+    it(
+        "should lower timestamps until the first non-duplicated one if valid anchor gathering function passed",
+        function()
+            Anchor_fct = function()
+                return {
+                    ["2010261208"] = "/path/to/my/anchor.md",
+                    ["1910291645"] = "/path/to/my/other_anchor.md"
+                }
+            end
+            assert.same("1910291644", A.create(Test_date, Anchor_fct))
+        end)
+
+    it(
+        "should ignore duplicate timestamps if no anchor gathering function passed",
+        function() assert.same("1910291645", A.create(Test_date)) end)
 end)
 
 describe("prepend", function()
@@ -61,3 +77,33 @@ describe("extract", function()
                         "[%l][%u][%d][%d][%d][%u]"))
     end)
 end)
+
+describe("list", function()
+    it("should return a set of anchors", function()
+        local anchor_fct = function()
+            return {
+                ["2010261208"] = "/path/to/my/anchor.md",
+                ["2001011212"] = "/path/to/my/other_anchor.md"
+            }
+        end
+        assert.same({
+            ["2010261208"] = "/path/to/my/anchor.md",
+            ["2001011212"] = '/path/to/my/other_anchor.md'
+        }, A.list(anchor_fct))
+    end)
+end)
+
+describe("check_anchor_exists", function()
+    before_each(function()
+        Anchor_fct = function()
+            return {
+                ["2010261208"] = "/path/to/my/anchor.md",
+                ["2001011212"] = "/path/to/my/other_anchor.md"
+            }
+        end
+    end)
+    it("returns true if anchor in existing set",
+       function() assert.is_true(A.is_duplicate('2001011212', Anchor_fct)) end)
+    it("returns false if anchor not in existing set",
+       function() assert.is_false(A.is_duplicate('2001011210', Anchor_fct)) end)
+end)

lua/zettelkasten/files.lua

@@ -24,6 +24,7 @@ end
 -- TODO transform paths:
 --    * to ensure / at the end (or no /) gets taken into account
 function ls.get_anchors_and_paths(fileset)
+    fileset = fileset or ls.get_all_files(o.zettel().rootdir, true)
     -- TODO check for duplicates and warn user
     local zettel = {}
     local anchorreg = '^.*/?(' .. o.anchor().regex .. ')[^/]*%' ..

lua/zettelkasten/link.lua

@@ -2,6 +2,7 @@ local L = {}
 
 local o = require 'zettelkasten.options'
 local a = require 'zettelkasten.anchor'
+local f = require 'zettelkasten.files'
 
 local parsers = {
     markdown = {
@@ -58,7 +59,7 @@ end
 -- Takes an optional link text which will be added to the link.
 -- Takes an optional style according to which the link will be transformed.
 function L.new(text, style)
-    local anchor = a.create()
+    local anchor = a.create(nil, f.get_anchors_and_paths)
     return L.create(anchor, text, style)
 end
 

lua/zettelkasten/link_spec.lua

@@ -1,4 +1,4 @@
-link = require 'zettelkasten.link'
+local link = require 'zettelkasten.link'
 Test_date = {year = 2019, month = 10, day = 29, hour = 16, min = 45}
 
 before_each(function() _G.vim = {g = {}, b = {}} end)
@@ -79,6 +79,12 @@ describe("create", function()
 end)
 
 describe("new", function()
+    before_each(function()
+        vim.loop = {
+            fs_scandir = function(_) return false end,
+            fs_scandir_next = function(_) end
+        }
+    end)
     it("should create a link out of only text input", function()
         local result = link.new("My FILE NAME")
         assert.is_not_nil(result:match(

lua/zettelkasten/text.lua

@@ -90,7 +90,9 @@ end
 --- @param linenr number
 --- @return string
 function T.get_line(linenr)
-    if linenr then return vim.api.nvim_buf_get_lines(0, linenr - 1, linenr, false)[1] end
+    if linenr then
+        return vim.api.nvim_buf_get_lines(0, linenr - 1, linenr, false)[1]
+    end
     return vim.api.nvim_get_current_line()
 end