local Config = require("persistence.config")

local M = {}

local e = vim.fn.fnameescape

function M.get_current()
  local pattern = "/"
  if vim.fn.has("win32") == 1 then
    pattern = '[\\:]'
  end
  local name = vim.fn.getcwd():gsub(pattern, "%%")
  return Config.options.dir .. name .. ".vim"
end

function M.get_branch()
  local git_enabled = (vim.fn.isdirectory(vim.fn.getcwd()..'/.git') == 1)

  if Config.options.use_git_branch == true and git_enabled == true then
    local branch = vim.api.nvim_exec([[!git rev-parse --abbrev-ref HEAD 2>/dev/null]], true)

    -- The branch command returns two lines. We only need the second line
    local lines = {}
    for s in branch:gmatch("[^\r\n]+") do
      table.insert(lines, '_' .. s)
    end
    return lines[2]:gsub("/", "%%")
  end

  return ''
end

function M.get_last()
  local sessions = M.list()
  table.sort(sessions, function(a, b)
    return vim.loop.fs_stat(a).mtime.sec > vim.loop.fs_stat(b).mtime.sec
  end)
  return sessions[1]
end

function M.setup(opts)
  Config.setup(opts)
  M.start()
end

function M.start()
  vim.cmd([[
    augroup Persistence
      autocmd!
      autocmd VimLeavePre * lua require("persistence").save()
    augroup end
  ]])
  vim.g.using_persistence = true
end

function M.stop()
  vim.cmd([[
    autocmd! Persistence
    augroup! Persistence
  ]])
  vim.g.using_persistence = false
end

function M.save()
  local tmp = vim.o.sessionoptions
  vim.o.sessionoptions = table.concat(Config.options.options, ",")
  vim.cmd("mks! " .. e(M.get_current()))
  vim.o.sessionoptions = tmp
  vim.g.using_persistence = true
end

function M.load(opt)
  opt = opt or {}
  local sfile = opt.last and M.get_last() or M.get_current()
  if sfile and vim.fn.filereadable(sfile) ~= 0 then
    vim.cmd("source " .. e(sfile))
    vim.g.using_persistence = true
  end
end

function M.list()
  return vim.fn.glob(Config.options.dir .. "*.vim", true, true)
end

return M