(** Example usage of the CacheIO library *)

open Eio

let setup_logs () =
  Logs.set_level (Some Logs.Info);
  Logs.set_reporter (Logs_fmt.reporter ())

(** Example: Using CacheIO for caching data *)
let cache_example env sw =
  Printf.printf "CacheIO Example\n";
  Printf.printf "===============\n\n";

  (* Create cache in temp directory *)
  let base_dir = Path.(env#fs / "/tmp/cacheio-example") in
  let cache = Cacheio.create ~base_dir in

  (* Example 1: Cache some text data *)
  Printf.printf "1. Caching text data...\n";
  let key1 = "document.txt" in
  let data1 = "This is an example document that we're caching." in
  let source1 = Flow.string_source data1 in
  Cacheio.put cache ~key:key1 ~source:source1 ~ttl:(Some 3600.) ();
  Printf.printf "   Cached '%s'\n" key1;

  (* Example 2: Cache with no expiry *)
  let key2 = "permanent-data.txt" in
  let data2 = "This data never expires" in
  let source2 = Flow.string_source data2 in
  Cacheio.put cache ~key:key2 ~source:source2 ();
  Printf.printf "   Cached '%s' (no expiry)\n" key2;

  (* Example 3: Retrieve cached data *)
  Printf.printf "\n2. Retrieving cached data...\n";
  (match Cacheio.get cache ~key:key1 ~sw with
   | Some source ->
       let buf = Buffer.create 100 in
       let cstruct = Cstruct.create 100 in
       let rec read () =
         try
           match Flow.single_read source cstruct with
           | 0 -> ()
           | n ->
               Buffer.add_string buf (Cstruct.to_string (Cstruct.sub cstruct 0 n));
               read ()
         with End_of_file -> ()
       in
       read ();
       Printf.printf "   Retrieved: '%s'\n" (Buffer.contents buf)
   | None ->
       Printf.printf "   Key not found or expired\n");

  (* Example 4: Working with flags *)
  Printf.printf "\n3. Working with flags...\n";

  (* Pin an important file *)
  Cacheio.add_flag cache ~key:key2 `Pinned;
  Printf.printf "   Pinned '%s'\n" key2;

  (* Mark a file as stale *)
  Cacheio.add_flag cache ~key:key1 `Stale;
  Printf.printf "   Marked '%s' as stale\n" key1;

  (* Example 5: Cache statistics *)
  Printf.printf "\n4. Cache statistics:\n";
  let stats = Cacheio.stats cache in
  let open Cacheio.Stats in
  Printf.printf "   Total entries: %d\n" (entry_count stats);
  Printf.printf "   Total size: %Ld bytes\n" (total_size stats);
  Printf.printf "   Expired entries: %d\n" (expired_count stats);
  Printf.printf "   Pinned entries: %d\n" (pinned_count stats);
  Printf.printf "   Stale entries: %d\n" (stale_count stats);

  (* Example 6: Scan cache *)
  Printf.printf "\n5. Cache contents:\n";
  let entries = Cacheio.scan cache in
  List.iter (fun entry ->
    let flags_str = Format.asprintf "%a" Cacheio.Flags.pp (Cacheio.Entry.flags entry) in
    let ttl_str = match Cacheio.Entry.ttl entry with
      | None -> "never"
      | Some t ->
          let remaining = t -. Unix.time () in
          if remaining > 0. then Printf.sprintf "%.0fs" remaining
          else "expired"
    in
    Printf.printf "   %s: %Ld bytes, expires: %s, flags: %s\n"
      (String.sub (Cacheio.Entry.key entry) 0 16) (Cacheio.Entry.size entry) ttl_str flags_str
  ) entries;

  (* Example 7: Expire old entries *)
  Printf.printf "\n6. Expiring old entries...\n";
  let expired_count = Cacheio.expire cache in
  Printf.printf "   Removed %d expired entries\n" expired_count;

  (* Example 8: Clear temporary entries *)
  Printf.printf "\n7. Clear temporary entries...\n";
  Cacheio.clear_temporary cache;
  Printf.printf "   Cleared all temporary entries\n"

let () =
  setup_logs ();
  Eio_main.run @@ fun env ->
  Switch.run @@ fun sw ->
    cache_example env sw;
    Printf.printf "\nExample completed successfully!\n"