zettelkasten: Implement picker that wraps visual selection with link

Author: jpcenteno

lua/plugins/zettelkasten.lua

@@ -15,5 +15,14 @@ return {
       end,
       desc = "Open note",
     },
+    {
+      "<localleader>ln",
+      function()
+        require("zettelkasten.edit").surround_visual_selection_with_link_to_note()
+      end,
+      mode = "v",
+      ft = { "markdown" },
+      desc = "Surround with link to note",
+    },
   },
 }

myplugins/zettelkasten/lua/zettelkasten/edit.lua

@@ -0,0 +1,107 @@
+local nvim_utils = require("zettelkasten.utils.nvim")
+local path_utils = require("zettelkasten.utils.path")
+local pickers = require("zettelkasten.pickers")
+
+local M = {}
+
+---Inserts the string `s` at position.
+---@param position zettelkasten.utils.nvim.position.Position
+---@param s string
+local function insert_at_position(position, s)
+  local line_pre = vim.api.nvim_buf_get_lines(0, position.row - 1, position.row, true)[1]
+  local left = line_pre:sub(1, position.column - 1)
+  local right = line_pre:sub(position.column)
+  local line_post = left .. s .. right
+  vim.api.nvim_buf_set_lines(0, position.row - 1, position.row, true, { line_post })
+end
+
+--- Surrounds the text of a single-line visual range.
+--- @param visual_range VisualRange
+--- @param prefix string
+--- @param suffix string
+local function surround_single_line(visual_range, prefix, suffix)
+  assert(visual_range:is_single_line())
+
+  local row = visual_range.from.row
+  local line = vim.api.nvim_buf_get_lines(0, row - 1, row, true)[1]
+
+  local left = line:sub(1, visual_range.from.column - 1)
+  local center = line:sub(visual_range.from.column, visual_range.to.column)
+  local right = line:sub(visual_range.to.column + 1)
+
+  local surrounded = left .. prefix .. center .. suffix .. right
+  vim.api.nvim_buf_set_lines(0, row - 1, row, true, { surrounded })
+end
+
+--- Surrounds the text of a multi-line visual range.
+--- @param visual_range VisualRange
+--- @param prefix string
+--- @param suffix string
+local function surround_multi_line(visual_range, prefix, suffix)
+  assert(not visual_range:is_single_line())
+
+  insert_at_position(visual_range.from, prefix)
+  vim.notify(vim.inspect(visual_range.to))
+  insert_at_position(visual_range.to:offset_column(1), suffix)
+end
+
+--- Surrounds a range within the buffer with the `left` and `right` srings.
+---
+--- @param visual_range VisualRange
+--- @param left string
+--- @param right string
+function M.surround(visual_range, left, right)
+  if visual_range:is_single_line() then
+    surround_single_line(visual_range, left, right)
+  else
+    surround_multi_line(visual_range, left, right)
+  end
+end
+
+M.surround_visual_selection_with_link_to_note = function()
+  nvim_utils.assert_visual_mode()
+
+  --- Current visual range start position.
+  local _, row1, col1, _ = unpack(vim.fn.getpos("v"))
+  local row2, col2 = unpack(vim.api.nvim_win_get_cursor(0))
+  col2 = col2 + 1
+
+  if (row2 < row1) or (row1 == row2 and col2 < col1) then
+    row1, row2 = row2, row1
+    col1, col2 = col2, col1
+  end
+
+  pickers.pick_note({
+    confirm = function(picker, selected_item)
+      picker:close()
+      local url = path_utils.relative_to_parent_directory(selected_item.file)
+
+      if row1 == row2 then
+        local line = vim.api.nvim_buf_get_lines(0, row1 - 1, row1, true)[1]
+        local left = line:sub(1, col1 - 1)
+        local center = line:sub(col1, col2)
+        local right = line:sub(col2 + 1)
+
+        local wrapped_line = left .. "[" .. center .. "](" .. url .. ")" .. right
+
+        vim.api.nvim_buf_set_lines(0, row1 - 1, row1, true, { wrapped_line })
+      else
+        local line1 = vim.api.nvim_buf_get_lines(0, row1 - 1, row1, true)[1]
+        local left1 = line1:sub(1, col1 - 1)
+        local right1 = line1:sub(col1)
+        local wrapped_line1 = left1 .. "[" .. right1
+        vim.api.nvim_buf_set_lines(0, row1 - 1, row1, true, { wrapped_line1 })
+
+        local line2 = vim.api.nvim_buf_get_lines(0, row2 - 1, row2, true)[1]
+        local left2 = line2:sub(1, col2)
+        local right2 = line2:sub(col2 + 1)
+        local wrapped_line2 = left2 .. "](" .. url .. ")" .. right2
+        vim.api.nvim_buf_set_lines(0, row2 - 1, row2, true, { wrapped_line2 })
+      end
+
+      nvim_utils.press_esc()
+    end,
+  })
+end
+
+return M

myplugins/zettelkasten/lua/zettelkasten/pickers.lua

@@ -1,4 +1,6 @@
 local cli = require("zettelkasten.cli")
+local table_utils = require("zettelkasten.utils.table")
+
 local snacks = require("snacks")
 
 local M = {}
@@ -22,4 +24,24 @@ M.open_note = function()
   })
 end
 
+--- Pick notes from the zettelkasten.
+--- @param opts table?
+M.pick_note = function(opts)
+  local notes = cli.note_list()
+
+  local items = {}
+  for _, note in ipairs(notes) do
+    items[#items + 1] = {
+      file = note.location,
+      text = note.title,
+    }
+  end
+
+  local mutable_opts = table_utils.shallow_copy(opts or {})
+  mutable_opts.items = items
+  mutable_opts.format = "text" -- Display the `text` field instead of the `file`.
+
+  snacks.picker.pick(mutable_opts)
+end
+
 return M

myplugins/zettelkasten/lua/zettelkasten/utils/nvim.lua

@@ -0,0 +1,26 @@
+local M = {}
+
+function M.is_visual_mode()
+  return vim.fn.mode():match("[vV\22]")
+end
+
+---Asserts that the current mode is visual mode or throws an error.
+---@param msg string?
+M.assert_visual_mode = function(msg)
+  assert(M.is_visual_mode(), msg)
+end
+
+--- Returns the parent directory of the buffer.
+--- @param buffer integer
+--- @return string
+M.buf_get_directory = function(buffer)
+  local file_path = vim.api.nvim_buf_get_name(buffer)
+  return vim.fn.fnamemodify(file_path, ":h")
+end
+
+function M.press_esc()
+  local keys = vim.api.nvim_replace_termcodes("<Esc>", true, false, true)
+  vim.api.nvim_feedkeys(keys, "n", false)
+end
+
+return M

myplugins/zettelkasten/lua/zettelkasten/utils/nvim/position.lua

@@ -1,12 +1,12 @@
 --- Represents a position in the buffer.
---- @class (exact) Position
+--- @class (exact) zettelkasten.utils.nvim.position.Position
 --- @field row integer A positive integer.
 --- @field column integer A positive integer.
 local Position = {}
 
 --- Instantiates a new mark.
 --- @param o { row: integer, column: integer }
---- @return Position
+--- @return zettelkasten.utils.nvim.position.Position
 function Position:new(o)
   assert(type(o.column) == "number", "Field `column` must be a `number`")
   assert(o.column % 1 == 0, "Field `column` must be an integer")
@@ -15,14 +15,14 @@ function Position:new(o)
   assert(o.row % 1 == 0, "Field `row` must be an integer")
   assert(0 < o.row, "Field `row` must be positive")
 
-  setmetatable(o, self)
+  setmetatable(o, { __index = self })
   return o
 end
 
 --- Constructs a `Position` from a Vim `getpos` expression.
 ---
 --- @param expr string An expression accepted by `vim.fn.getpos`.
---- @return Position
+--- @return zettelkasten.utils.nvim.position.Position
 function Position:getpos(expr)
   local _, row, column, _ = unpack(vim.fn.getpos(expr))
   return Position:new({ row = row, column = column })
@@ -31,8 +31,18 @@ end
 --- Returns true if and only if this `Position` comes before the other
 --- `Position`.
 ---
---- @param other Position
+--- @param other zettelkasten.utils.nvim.position.Position
 --- @return boolean
 function Position:__lt(other)
   return self.row < other.row or (self.row == other.row and self.column < other.column)
 end
+
+--- Returns a new Position with the `column` field offset by `n`.
+---
+--- @param n number Integer column offset.
+--- @return zettelkasten.utils.nvim.position.Position
+function Position:offset_column(n)
+  return Position:new({ row = self.row, column = self.column + n })
+end
+
+return Position

myplugins/zettelkasten/lua/zettelkasten/utils/nvim/visualrange.lua

@@ -0,0 +1,34 @@
+--- @alias VisualMode
+---| "v"   # Character-wise Visual mode.
+---| "V"   # Line-wise Visual mode.
+---| "\22" # Block-range Visual mode. "\22" is the escaped form of Ctrl-V
+
+--- @class (exact) VisualRange
+--- @field mode VisualMode
+--- @field from zettelkasten.utils.nvim.position.Position
+--- @field to zettelkasten.utils.nvim.position.Position
+local VisualRange = {}
+
+--- Creates a new VisualRange.
+--- @param mode VisualMode
+--- @param from zettelkasten.utils.nvim.position.Position
+--- @param to zettelkasten.utils.nvim.position.Position
+--- @return VisualRange
+function VisualRange:new(mode, from, to)
+  -- normalize row/col order
+  if to < from then
+    from, to = to, from
+  end
+
+  local o = { mode = mode, from = from, to = to }
+  setmetatable(o, { __index = self })
+  return o
+end
+
+--- Returns true if the `VisualRange` does not span across multiple lines.
+--- @return boolean
+function VisualRange:is_single_line()
+  return self.from.row == self.to.row
+end
+
+return VisualRange

myplugins/zettelkasten/lua/zettelkasten/utils/nvim/window_buffer.lua

@@ -0,0 +1,65 @@
+--- Context: Visual selections relate to windows. The same buffer could be open
+--- in different windows and be in different modes with different cursor
+--- positions.
+
+local VisualRange = require("zettelkasten.utils.nvim.visualrange")
+
+--- @class zettelkasten.utils.nvim.WindowBuffer
+--- @field window_id integer
+--- @field buffer_id integer
+local WindowBuffer = {}
+
+function WindowBuffer:new(window_id)
+  assert(type(window_id) == "number" and window_id % 1 == 0 and window_id ~= 0)
+  local buffer_id = vim.api.nvim_win_get_buf(window_id)
+
+  return { window_id = window_id, buffer_id = buffer_id }
+end
+
+function WindowBuffer:current_window()
+  local window_id = vim.api.nvim_win_get_number(0)
+  return self:new(window_id)
+end
+
+function WindowBuffer:mode()
+  local cur_win = vim.api.nvim_get_current_win()
+  vim.api.nvim_set_current_win(self.window_id)
+  local mode = vim.api.nvim_get_mode().mode
+  vim.api.nvim_set_current_win(cur_win)
+  return mode
+end
+
+function WindowBuffer:selection_start()
+  local cur_win = vim.api.nvim_get_current_win()
+  vim.api.nvim_set_current_win(self.window_id)
+  local position = Position
+  vim.api.nvim_set_current_win(cur_win)
+  return mode
+end
+
+--- Returns the visual selection range.
+--- @return VisualRange
+function WindowBuffer:visual_range()
+  local mode = self:mode()
+  local from = self:selection_start()
+  local to = self:cursor_position()
+  return VisualRange:new(mode, from, to)
+end
+
+local M = {}
+
+function M.new(window_id)
+  assert(type(window_id) == "number" and window_id % 1 == 0 and window_id ~= 0)
+  local buffer_id = vim.api.nvim_win_get_buf(window_id)
+
+  local o = { window_id = window_id, buffer_id = buffer_id }
+  setmetatable(o, { __index = WindowBuffer })
+  return o
+end
+
+function M.current_window()
+  local window_id = vim.api.nvim_win_get_number(0)
+  return M.new(window_id)
+end
+
+return WindowBuffer

myplugins/zettelkasten/lua/zettelkasten/utils/path.lua

@@ -0,0 +1,10 @@
+local M = {}
+
+--- Returns the path relative to it's parent directory.
+--- @param path string
+--- @return string
+function M.relative_to_parent_directory(path)
+  return "./" .. path:match("([^/\\]+)$")
+end
+
+return M

myplugins/zettelkasten/lua/zettelkasten/utils/table.lua

@@ -1,5 +1,22 @@
 local M = {}
 
+--- Returns a shallow copy of table `t`.
+---
+--- @param t table
+M.shallow_copy = function(t)
+  local copy = {}
+
+  for index, value in ipairs(t) do
+    copy[index] = value
+  end
+
+  for key, value in pairs(t) do
+    copy[key] = value
+  end
+
+  return copy
+end
+
 --- Mutates `dst` by appending the elements from `src` in order. Ignores
 --- non-numeric keys.
 ---