local util = require("util")

local M = {}

M.local_plugins = {}

function M.bootstrap()
	local fn = vim.fn
	local install_path = fn.stdpath("data") .. "/site/pack/packer/opt/packer.nvim"
	if fn.empty(fn.glob(install_path)) >  0 then
		fn.system({"git", "clone", "--depth", "1", "https://github.com/wbthomason/packer.nvim", install_path})
		return true
	end

end

function M.auto_compile()
  local group = vim.api.nvim_create_augroup("PackerUserConfig", {})
  vim.api.nvim_create_autocmd("BufWritePost", {
    pattern = { "plugins.lua", "*/plugins/*.lua", "packer.lua" },
    group = group,
    callback = function()
      for p, _ in pairs(package.loaded) do
        if p:find("^plugins") or p == "config.plugins" or p == "util.packer" then
          package.loaded[p] = nil
        end
      end
      require("config.plugins")
      vim.cmd([[PackerCompile]])
      util.info("Packer compiled...")
    end,
  })
end

function M.use(spec, fn)
  if type(spec) == "string" then
    spec = { spec }
  elseif type(spec) == "table" and #spec > 1 then
    for i, child_spec in ipairs(spec) do
      spec[i] = M.use(child_spec, fn)
    end
    return
  end
  if
    type(spec.requires) == "string"
    or (type(spec.requires) == "table" and not vim.tbl_islist(spec.requires) and #spec.requires == 1)
  then
    spec.requires = { spec.requires }
  end
  if spec.requires then
    for i, v in ipairs(spec.requires) do
      spec.requires[i] = M.use(v, fn)
    end
  end
  fn(spec)
  return spec
end

function M.get_name(pkg)
  local parts = vim.split(pkg, "/")
  return parts[#parts], parts[1]
end

function M.has_local(name)
  return vim.loop.fs_stat(vim.fn.expand("~/projects/" .. name)) ~= nil
end

function M.wrap(use)
  return function(spec)
    spec = M.use(spec, M.process_plugin)
    use(spec)
  end
end

function M.process_plugin(spec)
  if spec.plugin then
    local ok, plugin = pcall(require, "plugins." .. spec.plugin)
    if not ok then
      util.error("Failed to load plugins." .. spec.plugin .. "\n\n" .. plugin)
    else
      for k, v in pairs(plugin) do
        -- what we call init, is called setup in Packer
        -- skip plugin.setup methods. Thos are to be called maually from scripts
        local kk = k == "init" and "setup" or k ~= "setup" and k
        if kk then
          spec[kk] = type(v) == "function" and ([[require("plugins.%s").%s()]]):format(spec.plugin, k) or v
        end
      end
    end
    spec.plugin = nil
  end
end

function M.plugin(pkg)
  local name = M.get_name(pkg):lower()
  name = name:gsub("%.n?vim$", "")
  name = name:gsub("^n?vim%-", "")
  name = name:gsub("%-n?vim$", "")
  name = name:gsub("%.lua$", "")
  name = name:gsub("%.", "_")
  return { pkg, plugin = name }
end

function M.setup(config, fn)
	local bootstrapped = M.bootstrap()
	M.auto_compile()

	vim.cmd([[packadd packer.nvim]])

	local packer = require("packer")
	packer.init(config)

	M.local_plugins = config.local_plugins or {}

	packer.startup(function(use)
		use = M.wrap(use)
		fn(use, function(pkg)
			return use(M.plugin(pkg))
		end)
	end)

	if bootstrapped then
		require("packer").sync()
	end
end

return M