open Mechaml
module M = Agent.Monad
open M.Infix

let require msg = function
  | Some a -> a
  | None -> failwith msg

let steam_search query =
  let url = "https://store.steampowered.com/" in
  Agent.get url
  >|= (fun result ->
    let form = result
      |> Agent.HttpResponse.page
      |> Page.form_with "[id=searchform]"
      |> require "search form not found" in
    let field = form
      |> Page.Form.field_with "[name=term]"
      |> require "q field not found" in
    Page.Form.Field.set form field query)
  >>= Agent.submit
  >>= (fun response ->
    response
    |> Agent.HttpResponse.content
    |> M.save_content "steam-result.html")

let _ =
  M.run (Agent.init ()) (steam_search "planet")