;; ported-from: src/ingest.ts @ v1.0.0 (extracted-from: bot/src/rl/train.ts @ fa686ee,
;;   expandDirs + the ingest-state load/save that framed the trainer script)
;;
;; Trainer-side plumbing for live-episode ingestion: expand per-bot episode
;; dir patterns and persist the byte offsets already consumed, so every
;; transition is trained on exactly once across runs.
(ns ardegazu.train.ingest
  (:require ["node:fs" :as fs]
            ["node:path" :as path]))

(defn expand-dirs
  "Expand one \"*\" path segment against the filesystem (per-bot state dirs)."
  [patterns]
  (let [out #js []]
    (dotimes [pi (.-length ^js patterns)]
      (let [p (aget patterns pi)
            star (.indexOf ^js p "*")]
        (if (< star 0)
          (.push out p)
          (let [base (.replace ^js (.slice ^js p 0 star) #"/[^/]*$" "")
                tail (.slice ^js p (inc (.indexOf ^js p "/" star)))]
            (try
              (let [entries (fs/readdirSync base #js {:withFileTypes true})]
                (dotimes [di (.-length entries)]
                  (let [d (aget entries di)]
                    (when ^boolean (.isDirectory ^js d)
                      (.push out (path/join base (.-name ^js d) tail))))))
              (catch :default _
                ;; base absent — nothing to ingest
                nil))))))
    out))

(defn ingest-state-path [model-dir]
  (path/join model-dir "ingest-state.json"))

(defn load-ingest-state
  "The persisted offsets, or a fresh state on first run / corrupt file."
  [model-dir]
  (try
    (js/JSON.parse (fs/readFileSync (ingest-state-path model-dir) "utf8"))
    (catch :default _
      ;; first run (or corrupt — re-ingest is idempotent enough)
      #js {:offsets #js {}})))

(defn save-ingest-state [model-dir state]
  (fs/mkdirSync model-dir #js {:recursive true})
  (fs/writeFileSync (ingest-state-path model-dir) (js/JSON.stringify state))
  js/undefined)