-- Copyright (c) 2024 Florian Fischer. All rights reserved.
--
-- vis-lockfiles is free software: you can redistribute it and/or modify it under
-- the terms of the GNU General Public License as published by the Free Software
-- Foundation, either version 3 of the License, or (at your option) any later
-- version.
--
-- vis-lockfiles is distributed in the hope that it will be useful, but WITHOUT
-- ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
-- FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
--
-- You should have received a copy of the GNU General Public License along with
-- vis-lockfiles found in the LICENSE file.
-- If not, see <https://www.gnu.org/licenses/>.
local source_str = debug.getinfo(1, 'S').source:sub(2)
local script_path = source_str:match('(.*/)')

local lockfiles = dofile(script_path .. 'lockfiles.lua')

-- function used for all actions resulting from a FILE_OPEN event that can not
-- be done during the handler
local pending_action = nil

--[[
local function count_windows()
  -- Count the currently open vis windows
  local n = 0
  for _ in vis:windows() do
    n = n + 1
  end
  return n
end
]] --

local M = {}
M.directory = '${XDG_STATE_HOME:-${HOME}/.local/state}/vis/locks'
M.directory_expanded = nil

local function get_lock_dir()
  if M.directory_expanded ~= M.directory then
    M.directory = lockfiles.capture_cmd('printf %s "' .. M.directory .. '"')
    M.directory_expanded = M.directory
  end
  return M.directory
end

-- get a user confirmation
-- return true if user selected yes, false otherwise
local function prompt(path, lfile_path, pid)
  local choices = 'a\ne\nq'
  local msg = 'Lock file found!\n\t lock file: "' .. lfile_path .. '"\n\tfile name: ' .. path ..
                  '\n\tprocess ID: ' .. pid

  local menu_prompt = '(E)dit anyway, (Q)uit, [A]bort'
  local cmd1 = 'printf >/dev/tty %s \'' .. msg .. '\n\''
  local cmd2 = 'printf %s \'' .. choices .. '\''
  local cmd3 = 'vis-menu -b -p \'' .. menu_prompt .. '\''
  local cmd = cmd1 .. ';' .. cmd2 .. '|' .. cmd3

  local status, output = vis:pipe(cmd, true)
  vis:redraw()

  if status == 0 then
    if output:sub(1, 1) == 'e' then
      return true
    elseif output:sub(1, 1) == 'q' then
      vis:exit(1)
    end
  end

  -- else 'abort' or dialog canceled

  local hnd1
  hnd1 = function()
    if vis.win.file and vis.win.file.path == path then
      vis.events.unsubscribe(vis.events.UI_DRAW, hnd1)
      vis:command('q')
      vis:command('new')
    end
  end
  vis.events.subscribe(vis.events.UI_DRAW, hnd1)
  vis:redraw()
end

local created_locks = {}

vis.events.subscribe(vis.events.WIN_OPEN, function(win)
  local file = win.file
  if created_locks[file.path] or not file.path then
    -- either a noname buffer, or already locked by us
    return
  end

  local lfile_path = lockfiles.lock_file_path(get_lock_dir(), file.path)
  local lock_pid = lockfiles.create_lock_file(get_lock_dir(), lfile_path)
  if lockfiles.vis_pid == lock_pid then
    created_locks[file.path] = lfile_path
  else
    prompt(file.path, lfile_path, lock_pid)
  end
end)

vis.events.subscribe(vis.events.FILE_CLOSE, function(file)
  if not file.path then
    return
  end
  local lfile_path = created_locks[file.path]
  if lfile_path then
    lockfiles.delete_lock_file(lfile_path)
    created_locks[file.path] = nil
  end
end)

vis.events.subscribe(vis.events.QUIT, function()
  for _, lfile_path in pairs(created_locks) do
    if lfile_path then
      lockfiles.delete_lock_file(lfile_path)
    end
  end
  created_locks = {}
end)

vis.events.subscribe(vis.events.UI_DRAW, function()
  if not pending_action or not vis.win then
    return
  end

  if pending_action() then
    pending_action = nil
  end
end)

return M