local extensions = {}

extensions._loaded = {}
extensions._config = {}

--- Register an extension module.
---
--- Extensions have several important keys.
---     - setup:
---         function(ext_config, config) -> nil
---
---         Called when first loading the extension.
---         The first parameter is the config passed by the user
---             in telescope setup. The second parameter is the resulting
---             config.values after applying the users setup defaults.
---
---         It is acceptable for a plugin to override values in config,
---         as some plugins will be installed simply to manage some setup,
---         install some sorter, etc.
---
---     - exports:
---         table
---
---         Only the items in `exports` will be exposed on the  resulting
---         module that users can access via require('telescope').extensions.foo
---
---         Other things in the module will not be accessible. This is the public API
---         for your extension. Consider not breaking it a lot :laugh:
---
--- TODO:
---     - actions
extensions.register = function(mod)
  return mod
end

extensions.load = function(name)
  return extensions.manager[name]
end

extensions.set_config = function(extensions_config)
  extensions._config = extensions_config or {}

  for ext in pairs(extensions._config) do
    extensions.load(ext)
  end
end

extensions._setup_extension = function(name, ext, conf)
  if ext.setup then
    print("Calling setup for ext: ", name)
    ext.setup(conf or {}, require('telescope.config').values)
  end
end

extensions.manager = setmetatable({}, {
  __index = function(t, k)
    -- See if this extension exists.
    local ok, ext = pcall(require, 'telescope._extensions.' .. k)
    if not ok then
      error("This extension doesn't exist or is not installed: " .. k .. "\n" .. ext)
    end

    extensions._setup_extension(k, ext, extensions._config[k])

    t[k] = ext.exports or {}
    return t[k]
  end,
})


return extensions