path: root/runtime/lua/vim/_extui/messages.lua

local api, fn, o = vim.api, vim.fn, vim.o
local ext = require('vim._extui.shared')

---@class vim._extui.messages
local M = {
  -- Message window. Used for regular messages with 'cmdheight' == 0 or,
  -- cfg.msg.target == 'msg'. Automatically resizes to the text dimensions up to
  -- a point, at which point only the most recent messages will fit and be shown.
  -- A timer is started for each message whose callback will remove the message
  -- from the window again.
  msg = {
    count = 0, -- Number of messages currently in the message window.
    width = 1, -- Current width of the message window.
    timer = nil, ---@type uv.uv_timer_t Timer that removes the most recent message.
  },
  -- Cmdline message window. Used for regular messages with 'cmdheight' > 0.
  -- Also contains 'ruler', 'showcmd' and search_cmd/count messages as virt_text.
  -- Messages that don't fit the 'cmdheight' are cut off and virt_text is added
  -- to indicate the number of spilled lines and repeated messages.
  cmd = {
    count = 0, -- Number of messages currently in the message window.
    msg_row = -1, -- Last row of message to distinguish for placing virt_text.
    last_col = o.columns, -- Crop text to start column of 'last' virt_text.
    last_emsg = 0, -- Time an error was printed that should not be overwritten.
  },
  dupe = 0, -- Number of times message is repeated.
  prev_msg = '', -- Concatenated content of the previous message.
  virt = { -- Stored virt_text state.
    last = { {}, {}, {}, {} }, ---@type MsgContent[] status in last cmdline row.
    msg = { {}, {} }, ---@type MsgContent[] [(x)] indicators in msg window.
    top = { {} }, ---@type MsgContent[] [+x] top indicator in dialog window.
    bot = { {} }, ---@type MsgContent[] [+x] bottom indicator in dialog window.
    idx = { mode = 1, search = 2, cmd = 3, ruler = 4, spill = 1, dupe = 2 },
    ids = {}, ---@type { ['last'|'msg'|'top'|'bot']: integer? } Table of mark IDs.
    delayed = false, -- Whether placement of 'last' virt_text is delayed.
  },
  on_dialog_key = 0, -- vim.on_key namespace for paging in the dialog window.
}

function M.msg:close()
  self.width, M.virt.msg[M.virt.idx.dupe][1] = 1, nil
  M.prev_msg = ext.cfg.msg.target == 'msg' and '' or M.prev_msg
  api.nvim_buf_clear_namespace(ext.bufs.msg, -1, 0, -1)
  if api.nvim_win_is_valid(ext.wins.msg) then
    api.nvim_win_set_config(ext.wins.msg, { hide = true })
  end
end

--- Start a timer whose callback will remove the message from the message window.
---
---@param buf integer Buffer the message was written to.
---@param len integer Number of rows that should be removed.
function M.msg:start_timer(buf, len)
  self.timer = vim.defer_fn(function()
    if self.count == 0 or not api.nvim_buf_is_valid(buf) then
      return -- Messages moved to pager or buffer was closed.
    end
    api.nvim_buf_set_lines(buf, 0, len, false, {})
    self.count = self.count - 1
    -- Resize or hide message window for removed message.
    if self.count > 0 then
      M.set_pos('msg')
    else
      self:close()
    end
  end, ext.cfg.msg.timeout)
end

local cmd_on_key = nil
--- Place or delete a virtual text mark in the cmdline or message window.
---
---@param type 'last'|'msg'|'top'|'bot'
---@param tar? 'cmd'|'msg'|'dialog'
local function set_virttext(type, tar)
  if (type == 'last' and (ext.cmdheight == 0 or M.virt.delayed)) or cmd_on_key then
    return -- Don't show virtual text while cmdline, error or full message in cmdline is shown.
  end

  -- Concatenate the components of M.virt[type] and calculate the concatenated width.
  local width, chunks = 0, {} ---@type integer, [string, integer|string][]
  local contents = M.virt[type] ---@type MsgContent[]
  for _, content in ipairs(contents) do
    for _, chunk in ipairs(content) do
      chunks[#chunks + 1] = { chunk[2], chunk[3] }
      width = width + api.nvim_strwidth(chunk[2])
    end
  end
  tar = tar or type == 'msg' and ext.cfg.msg.target or 'cmd'

  if M.virt.ids[type] and #chunks == 0 then
    api.nvim_buf_del_extmark(ext.bufs[tar], ext.ns, M.virt.ids[type])
    M.cmd.last_col = type == 'last' and o.columns or M.cmd.last_col
    M.virt.ids[type] = nil
  elseif #chunks > 0 then
    local win = ext.wins[tar]
    local line = (tar == 'msg' or type == 'top') and 'w0' or type == 'bot' and 'w$'
    local srow = line and fn.line(line, ext.wins.dialog) - 1
    local erow = tar == 'cmd' and math.min(M.cmd.msg_row, api.nvim_buf_line_count(ext.bufs.cmd) - 1)
    local texth = api.nvim_win_text_height(win, {
      max_height = (type == 'top' or type == 'bot') and 1 or api.nvim_win_get_height(win),
      start_row = srow or nil,
      end_row = erow or nil,
    })
    local row = texth.end_row
    local col = fn.virtcol2col(win, row + 1, texth.end_vcol)
    local scol = fn.screenpos(win, row + 1, col).col ---@type integer

    if type ~= 'last' then
      -- Calculate at which column to place the virt_text such that it is at the end
      -- of the last visible message line, overlapping the message text if necessary,
      -- but not overlapping the 'last' virt_text.
      local offset = tar ~= 'msg' and 0
        or api.nvim_win_get_position(win)[2]
          + (api.nvim_win_get_config(win).border ~= 'none' and 1 or 0)

      -- Check if adding the virt_text on this line will exceed the current window width.
      local maxwidth = math.max(M.msg.width, math.min(o.columns, scol - offset + width))
      if tar == 'msg' and api.nvim_win_get_width(win) < maxwidth then
        api.nvim_win_set_width(win, maxwidth)
        M.msg.width = maxwidth
      end

      local mwidth = tar == 'msg' and M.msg.width or tar == 'dialog' and o.columns or M.cmd.last_col
      if scol - offset + width > mwidth then
        col = fn.virtcol2col(win, row + 1, texth.end_vcol - (scol - offset + width - mwidth))
      end

      -- Give virt_text the same highlight as the message tail.
      local pos, opts = { row, col }, { details = true, overlap = true, type = 'highlight' }
      local hl = api.nvim_buf_get_extmarks(ext.bufs[tar], ext.ns, pos, pos, opts)
      for _, chunk in ipairs(hl[1] and chunks or {}) do
        chunk[2] = hl[1][4].hl_group
      end
    else
      local mode = #M.virt.last[M.virt.idx.mode]
      local pad = o.columns - width ---@type integer
      local newlines = math.max(0, ext.cmdheight - texth.all)
      row = row + newlines
      M.cmd.last_col = mode > 0 and 0 or o.columns - (newlines > 0 and 0 or width)

      if newlines > 0 then
        -- Add empty lines to place virt_text on the last screen row.
        api.nvim_buf_set_lines(ext.bufs.cmd, -1, -1, false, fn['repeat']({ '' }, newlines))
        col = 0
      else
        if scol > M.cmd.last_col then
          -- Give the user some time to read an important message.
          if os.time() - M.cmd.last_emsg < 2 then
            M.virt.delayed = true
            vim.defer_fn(function()
              M.virt.delayed = false
              set_virttext('last')
            end, 2000)
            return
          end

          -- Crop text on last screen row and find byte offset to place mark at.
          local vcol = texth.end_vcol - (scol - M.cmd.last_col)
          col = vcol <= 0 and 0 or fn.virtcol2col(win, row + 1, vcol)
          M.prev_msg = mode > 0 and '' or M.prev_msg
          M.virt.msg = mode > 0 and { {}, {} } or M.virt.msg
          api.nvim_buf_set_text(ext.bufs.cmd, row, col, row, -1, { mode > 0 and ' ' or '' })
        end

        pad = pad - ((mode > 0 or col == 0) and 0 or math.min(M.cmd.last_col, scol))
      end
      table.insert(chunks, mode + 1, { (' '):rep(pad) })
      set_virttext('msg') -- Readjust to new M.cmd.last_col or clear for mode.
    end

    M.virt.ids[type] = api.nvim_buf_set_extmark(ext.bufs[tar], ext.ns, row, col, {
      virt_text = chunks,
      virt_text_pos = 'overlay',
      right_gravity = false,
      undo_restore = false,
      invalidate = true,
      id = M.virt.ids[type],
      priority = type == 'msg' and 2 or 1,
    })
  end
end

-- We need to keep track of the current message column to be able to
-- append or overwrite messages for :echon or carriage returns.
local col, will_full, hlopts = 0, false, { undo_restore = false, invalidate = true, priority = 1 }
--- Move messages to cmdline or pager to show in full.
local function msg_to_full(src)
  if will_full then
    return
  end
  will_full, M.prev_msg = true, ''

  vim.schedule(function()
    -- Copy and clear message from src to enlarged cmdline that is dismissed by any
    -- key press, or append to pager in case that is already open (not hidden).
    local hidden = api.nvim_win_get_config(ext.wins.pager).hide
    local tar = hidden and 'cmd' or 'pager'
    if tar ~= src then
      local srow = hidden and 0 or api.nvim_buf_line_count(ext.bufs.pager)
      local marks = api.nvim_buf_get_extmarks(ext.bufs[src], -1, 0, -1, { details = true })
      local lines = api.nvim_buf_get_lines(ext.bufs[src], 0, -1, false)
      api.nvim_buf_set_lines(ext.bufs[src], 0, -1, false, {})
      api.nvim_buf_set_lines(ext.bufs[tar], srow, -1, false, lines)
      for _, mark in ipairs(marks) do
        hlopts.end_col, hlopts.hl_group = mark[4].end_col, mark[4].hl_group
        api.nvim_buf_set_extmark(ext.bufs[tar], ext.ns, srow + mark[2], mark[3], hlopts)
      end
      if tar == 'cmd' and ext.cmd.highlighter then
        ext.cmd.highlighter.active[ext.bufs.cmd] = nil
      elseif tar == 'pager' then
        api.nvim_command('norm! G')
      end
      M.virt.msg[M.virt.idx.spill][1] = nil
    else
      for _, id in pairs(M.virt