local git = require('repl_plugin.git')
local M = {}

local api = vim.api
local fn = vim.fn

local config = {}
local last_branch = nil
local timer_id = nil

function M.setup(cfg)
  config = cfg or {}
end

function M.sync_once(cb)
  cb = cb or function() end
  git.get_branch(config.main_repo_path, function(err, branch)
    if err or not branch or branch == '' then
      vim.notify('Could not determine main repo branch', vim.log.levels.WARN)
      return cb('no_branch')
    end
    if branch == last_branch then
      return cb(nil, {changed=false})
    end

    -- attempt to commit repl repo if dirty
    git.commit_if_dirty(config.repl_repo_path, {auto_commit = config.auto_commit}, function(cerr, cres)
      if cerr then
        vim.notify('Failed to commit REPL repo: ' .. tostring(cerr), vim.log.levels.ERROR)
        return cb('commit_failed')
      end
      -- proceed to ensure branch exists and checkout
      git.branch_exists(config.repl_repo_path, branch, function(_, exists)
        if exists then
          git.checkout_branch(config.repl_repo_path, branch, function(co_err, ok)
            if co_err then
              vim.notify('Failed to checkout repl branch: ' .. tostring(co_err), vim.log.levels.ERROR)
              return cb('checkout_failed')
            end
            last_branch = branch
            vim.notify('Repl switched to branch: ' .. branch, vim.log.levels.INFO)
            return cb(nil, {changed=true, branch=branch})
          end)
        else
          -- prefer template
          git.branch_exists(config.repl_repo_path, 'template', function(_, tmpl)
            local from = tmpl and 'template' or 'HEAD'
            git.create_branch(config.repl_repo_path, branch, from, function(cr_err, ok)
              if cr_err then
                vim.notify('Failed to create repl branch: ' .. tostring(cr_err), vim.log.levels.ERROR)
                return cb('create_failed')
              end
              last_branch = branch
              vim.notify('Repl branch created: ' .. branch, vim.log.levels.INFO)
              return cb(nil, {changed=true, branch=branch})
            end)
          end)
        end
      end)
    end)
  end)
end

function M.start(interval)
  if timer_id then
    vim.notify('REPL sync already running', vim.log.levels.INFO)
    return
  end
  interval = interval or config.poll_interval or 5000
  timer_id = fn.timer_start(interval, function()
    vim.schedule(function() M.sync_once() end)
  end, {['repeat'] = -1})
  vim.notify('Started REPL sync (interval ' .. tostring(interval) .. ' ms)', vim.log.levels.INFO)
end

function M.stop()
  if timer_id then
    pcall(fn.timer_stop, timer_id)
    timer_id = nil
    vim.notify('Stopped REPL sync', vim.log.levels.INFO)
  end
end

return M