updateview.lua

local uv = vim.loop
local api = vim.api
local tinsert = table.insert

local UPDATE_INTERVAL = 50 -- minimum time in ms to flush changes
local COLUMN_WIDTH    = 50 -- plugin uri column width

---@type NeopmState
local state = require('neopm.state')

---@type number
local bufnr

---@class NeopmUpdateView
---@field bufnr number
---@field lines string[]
---@field last_update number
---@field pending_redraw boolean
local UpdateView = {}
UpdateView.__index = UpdateView

--- Create a new update view
---@return NeopmUpdateView
function UpdateView.new()
  if bufnr and api.nvim_buf_is_loaded(bufnr) then
    api.nvim_set_current_buf(bufnr)
  else
    vim.cmd([[
      enew
      setl buftype=nofile
      setl nowrap
    ]])
    bufnr = api.nvim_get_current_buf()

    local ok, err = pcall(api.nvim_buf_set_name, bufnr, 'neopm://update')
    if not ok then
      if err:match('^Vim:E95:') then
        local created = false
        for i = 2, 999 do -- to not go forever if something goes wrong I guess
          ok, err = pcall(api.nvim_buf_set_name, bufnr, 'neopm://update('..i..')')
          if ok then
            created = true
            break
          elseif not err:match('^Vim:E95:') then
            error(err)
          end
        end
        if not created then
          error('failed to create a new buffer')
        end
      else
        error(err)
      end
    end
  end

  api.nvim_buf_set_option(bufnr, 'modifiable', false)

  local lines = {}
  -- populate buffer with plugin uris
  for i, plug in ipairs(state.by_order) do
    lines[i] = plug.uri
  end
  -- add line for global status
  tinsert(lines, '')

  local this = setmetatable({
    bufnr = bufnr,
    lines = lines,
    last_update = uv.now(),
    pending_redraw = false,
  }, UpdateView)

  return this
end

--- Set plugin status string
---@param plug NeopmPlug
---@param status string
function UpdateView:set(plug, status)
  self.lines[plug.order] = plug.uri..string.rep(' ', COLUMN_WIDTH - #plug.uri)..status
  self.pending_redraw = true
end

--- Set global status string
---@param status string
function UpdateView:global(status)
  self.lines[#self.lines] = status
  self.pending_redraw = true
  self:flush(true)
end

--- Flush changes to the buffer
---@param force? boolean  Update the buffer immediately
function UpdateView:flush(force)
  if not self.pending_redraw then
    return
  end

  local now = uv.now()
  if not force and now - self.last_update < UPDATE_INTERVAL then
    return
  end

  self.last_update = now
  self.pending_redraw = false
  api.nvim_buf_set_option(self.bufnr, 'modifiable', true)
  api.nvim_buf_set_lines(self.bufnr, 0, -1, false, self.lines)
  api.nvim_buf_set_option(self.bufnr, 'modifiable', false)
  vim.cmd('redraw')
end

return UpdateView