very rough wip of saving between sessions

lua/before.lua

@@ -23,14 +23,22 @@ local function is_regular_buffer(bufnr)
 end
 
 local function should_remove(location)
-  return not bufvalid(location.bufnr) or not within_bounds(location.bufnr, location.line) or
+  local invalid_bufnr = not bufvalid(location.bufnr) or not within_bounds(location.bufnr, location.line) or
       not is_regular_buffer(location.bufnr)
+
+  -- then try to look up filename
+  local invalid_file = not vim.fn.filereadable(location.file)
+
+  -- return invalid_bufnr or invalid_file?
+  --  TODO: don't really know what to do here
+  return false
 end
 
 function M.track_edit()
   local bufnr = vim.api.nvim_get_current_buf()
+  local file = vim.api.nvim_buf_get_name(bufnr)
   local pos = vim.api.nvim_win_get_cursor(0)
-  local location = { bufnr = bufnr, line = pos[1], col = pos[2] }
+  local location = { file = file, bufnr = bufnr, line = pos[1], col = pos[2] }
   local prev_location = M.edit_locations[#M.edit_locations]
 
   if is_regular_buffer(bufnr) then
@@ -49,6 +57,8 @@ function M.track_edit()
     table.remove(M.edit_locations, 1)
     M.cursor = M.max_entries
   end
+
+  M.save_cache()
 end
 
 local function find_backwards_jump(currentLocation)
@@ -106,14 +116,22 @@ end
 function M.jump_to_last_edit()
   if #M.edit_locations > 0 then
     local bufnr = vim.api.nvim_get_current_buf()
+    local file = vim.api.nvim_buf_get_name(bufnr)
     local pos = vim.api.nvim_win_get_cursor(0)
-    local current = { bufnr = bufnr, line = pos[1], col = pos[2] }
+    local current = { file = file, bufnr = bufnr, line = pos[1], col = pos[2] }
 
     local new_location = find_backwards_jump(current)
 
-    if new_location then
-      vim.api.nvim_win_set_buf(0, new_location.bufnr)
+    vim.print(vim.inspect(new_location))
+
+    if new_location and new_location.file ~= file then
+      vim.api.nvim_command("e " .. new_location.file)
       vim.api.nvim_win_set_cursor(0, { new_location.line, new_location.col })
+    else
+      if new_location then
+        vim.api.nvim_win_set_buf(0, new_location.bufnr)
+        vim.api.nvim_win_set_cursor(0, { new_location.line, new_location.col })
+      end
     end
   else
     print("No edit locations stored.")
@@ -123,20 +141,92 @@ end
 function M.jump_to_next_edit()
   if #M.edit_locations > 0 then
     local bufnr = vim.api.nvim_get_current_buf()
+    local file = vim.api.nvim_buf_get_name(bufnr)
     local pos = vim.api.nvim_win_get_cursor(0)
-    local current = { bufnr = bufnr, line = pos[1], col = pos[2] }
+    local current = { file = file, bufnr = bufnr, line = pos[1], col = pos[2] }
 
     local new_location = find_forward_jump(current)
 
-    if new_location then
-      vim.api.nvim_win_set_buf(0, new_location.bufnr)
+    if new_location and new_location.file ~= file then
+      vim.api.nvim_command("e " .. new_location.file)
       vim.api.nvim_win_set_cursor(0, { new_location.line, new_location.col })
+    else
+      if new_location then
+        vim.api.nvim_win_set_buf(0, new_location.bufnr)
+        vim.api.nvim_win_set_cursor(0, { new_location.line, new_location.col })
+      end
     end
   else
     print("No edit locations stored.")
   end
 end
 
+function M.cache_path()
+  return vim.fn.stdpath("cache") .. "/before"
+end
+
+function M.save_cache()
+  local path = M.cache_path()
+
+  if vim.fn.isdirectory(path) == 0 then
+    vim.fn.mkdir(path, "p")
+  end
+
+  local cache = M.serialize_cache(M.edit_locations)
+
+  vim.fn.writefile(cache, path .. "/cache")
+end
+
+function M.load_cache()
+  local path = M.cache_path()
+
+  local success, data = pcall(vim.fn.readfile, path .. "/cache")
+  -- print("success", success)
+  if success then
+    M.edit_locations = M.deserialize_cache(data)
+    M.cursor = #M.edit_locations
+  else
+    -- do nothing?
+    -- M.edit_locations = {}
+  end
+
+  print("loaded cache", vim.inspect(M.edit_locations))
+end
+
+function M.serialize_cache(content)
+  local lines = {}
+  for _, location in ipairs(content) do
+    table.insert(lines, string.format("%s:%s:%s:%s", location.file, location.bufnr, location.line, location.col))
+  end
+
+  return lines
+end
+
+-- Loop through it and serialize it to a string:
+function M.deserialize_cache(lines)
+  local content = {}
+  for _, line in ipairs(lines) do
+    local parts = vim.fn.split(line, ":")
+
+    -- ignore repeated entries
+    local tableContains = function(tab, val)
+      for index, value in ipairs(tab) do
+        if value.file == val.file and value.bufnr == val.bufnr and value.line == val.line and value.col == val.col then
+          return true
+        end
+      end
+      return false
+    end
+
+    local entry = { file = parts[1], bufnr = tonumber(parts[2]), line = tonumber(parts[3]), col = tonumber(parts[4]) }
+    if not tableContains(content, entry) then
+      table.insert(content, entry)
+    end
+  end
+
+  return content
+end
+
 M.defaults = {
   history_size = 10
 }
@@ -152,6 +242,13 @@ function M.setup(opts)
       require('before').track_edit()
     end,
   })
+
+  vim.api.nvim_create_autocmd({ "VimEnter" }, {
+    pattern = '*',
+    callback = function()
+      M.load_cache()
+    end,
+  })
 end
 
 return M