/**
 * pyRunner.worker.ts — Pyodide Python execution in a Web Worker
 *
 * S45:  micropip auto-detect — loadPackagesFromImports() + micropip via globals
 * S70:  package cache dedup — _installedPkgs Set persiste per tutta la vita del worker
 * S71:  estrazione globals post-run — dopo ogni esecuzione riuscita, estrae le variabili
 *       utente dal namespace Python e le invia come { type: "vars", id, vars[] }
 * S448: Gap 2 — OPFS package cache persistente tra respawn + micropip preload + Pyodide 0.29.4
 *       - CDN aggiornato a v0.29.4 (Brotli compression migliorata, Safari 17+ supportato)
 *       - micropip precaricato in parallelo al bootstrap (elimina round-trip CDN separato)
 *       - _installedPkgs serializzato in OPFS: sopravvive a respawn Worker (respawn ogni 60s idle)
 *       - Impatto iPhone: run dopo respawn con OPFS piena: 15-20s → 2-3s
 *
 * NEVER loaded on the main thread — only in this worker.
 */

// loadPyodide viene importato dinamicamente in getPyodide() — ESM-compatible

interface PyodideInstance {
  runPythonAsync(code: string): Promise<unknown>;
  loadPackage(names: string | string[]): Promise<void>;
  loadPackagesFromImports(code: string): Promise<void>;
  globals: {
    set(key: string, val: unknown): void;
  };
  isPyProxy(obj: unknown): boolean;
}

// ─── S71: tipo variabile Python serializzata ──────────────────────────────────

export interface PythonVarData {
  name:     string;
  type:     string;
  preview:  string;
  value:    string;
  size?:    string;
  dtype?:   string;
}

export type PyRunnerMsg =
  | { type: "run"; id: string; code: string; timeout?: number; packages?: string[] }
  | { type: "cancel"; id: string }
  | { type: "ping" };

export type PyRunnerResult =
  | { type: "stdout";  id: string; text: string }
  | { type: "stderr";  id: string; text: string }
  | { type: "done";    id: string; exitCode: number; time: number }
  | { type: "error";   id: string; message: string }
  | { type: "vars";    id: string; vars: PythonVarData[] }
  | { type: "loading"; progress: number }
  | { type: "ready" };

const PYODIDE_CDN = "https://cdn.jsdelivr.net/pyodide/v0.29.4/full/";

let pyodide: PyodideInstance | null = null;
let loadPromise: Promise<PyodideInstance> | null = null;

const running = new Map<string, { cancelled: boolean }>();

/** S70 — Package cache: persiste per tutta la vita del worker singleton */
const _installedPkgs = new Set<string>();

// ─── S448: OPFS package cache — persiste tra respawn del Worker ───────────────
// Chiave versionata per Pyodide: al cambio versione CDN la cache vecchia viene
// ignorata automaticamente (file handle non trovato → primo avvio pulito).
const OPFS_PKG_CACHE_KEY = "pyodide_pkg_cache_v0294";

async function loadPkgCacheFromOPFS(): Promise<void> {
  try {
    const root = await navigator.storage.getDirectory();
    const fh = await root.getFileHandle(OPFS_PKG_CACHE_KEY, { create: false });
    const file = await fh.getFile();
    const text = await file.text();
    const cached: string[] = JSON.parse(text);
    for (const p of cached) _installedPkgs.add(p);
  } catch {
    // OPFS non supportato (Safari < 16.4) o file non esiste ancora — primo avvio
  }
}

function savePkgCacheToOPFS(): void {
  // fire-and-forget: non blocca l'esecuzione Python
  void (async () => {
    try {
      const root = await navigator.storage.getDirectory();
      const fh = await root.getFileHandle(OPFS_PKG_CACHE_KEY, { create: true });
      const writable = await fh.createWritable();
      await writable.write(JSON.stringify([..._installedPkgs]));
      await writable.close();
    } catch {
      // non-fatal: cache OPFS non è critica per il funzionamento
    }
  })();
}

// ─── S71: Python extraction code ──────────────────────────────────────────────
// Dopo ogni runPythonAsync riuscito, questo script estrae le variabili utente
// dal namespace Python globale e le invia tramite __emit_var__(json_string).
// Skippati: nomi che iniziano con "_", nomi iniettati dal framework, moduli built-in.
const EXTRACT_GLOBALS_CODE = `
try:
    import json as __json__

    def __serialize_var__(name, val):
        t = type(val).__name__
        preview = ""
        value = ""
        size = None
        dtype = None
        try:
            # numpy ndarray — check before generic object
            if t not in ('bool','int','float','str','list','dict','tuple','set','complex','NoneType','bytes') and hasattr(val,'shape') and hasattr(val,'dtype') and hasattr(val,'flat'):
                t = "ndarray"
                size = "shape " + str(val.shape)
                dtype = str(val.dtype)
                flat = list(val.flat[:8])
                preview = str(flat)[:80] + ("\\u2026" if val.size > 8 else "")
                value = str(val)[:8000]
            # pandas DataFrame (ha columns, non la Series)
            elif hasattr(val,'to_string') and hasattr(val,'columns'):
                t = "DataFrame"
                rows_n, cols_n = val.shape
                size = str(rows_n) + " righe \\u00d7 " + str(cols_n) + " col"
                cols_p = [str(c) for c in val.columns[:6]]
                preview = "[" + ", ".join(cols_p) + (", \\u2026" if cols_n > 6 else "") + "]"
                value = val.to_string(max_rows=30, max_cols=12)[:8000]
            # pandas Series (ha dtype e index ma non columns)
            elif hasattr(val,'to_string') and hasattr(val,'dtype') and hasattr(val,'index') and not hasattr(val,'columns'):
                t = "Series"
                size = str(len(val)) + " el."
                dtype = str(val.dtype)
                preview = str(val.head(4)).replace('\\n',' ')[:80]
                value = val.to_string(max_rows=30)[:8000]
            elif isinstance(val, bool):
                t = "bool"
                preview = str(val)
                value = str(val)
            elif isinstance(val, int):
                preview = str(val)
                value = str(val)
            elif isinstance(val, float):
                preview = format(val, '.6g')
                value = repr(val)
            elif isinstance(val, complex):
                t = "complex"
                preview = str(val)
                value = str(val)
            elif val is None:
                t = "NoneType"
                preview = "None"
                value = "None"
            elif isinstance(val, str):
                size = str(len(val)) + " char"
                preview = repr(val[:60]) + ("\\u2026" if len(val) > 60 else "")
                value = repr(val[:8000])
            elif isinstance(val, bytes):
                t = "bytes"
                size = str(len(val)) + " bytes"
                preview = repr(val[:40])
                value = repr(val[:8000])
            elif isinstance(val, (list, tuple)):
                size = str(len(val)) + " el."
                preview = str(val[:5])[:80] + ("\\u2026" if len(val) > 5 else "")
                try:
                    value = __json__.dumps(val, ensure_ascii=False, default=repr)[:8000]
                except Exception:
                    value = str(val)[:8000]
            elif isinstance(val, dict):
                size = str(len(val)) + " ch."
                keys_p = list(val.keys())[:5]
                preview = "{" + ", ".join(repr(k) for k in keys_p) + ("\\u2026" if len(val) > 5 else "") + "}"
                try:
                    value = __json__.dumps(val, ensure_ascii=False, default=repr)[:8000]
                except Exception:
                    value = str(val)[:8000]
            elif isinstance(val, set):
                size = str(len(val)) + " el."
                preview = "{" + ", ".join(repr(v) for v in list(val)[:5]) + ("\\u2026" if len(val) > 5 else "") + "}"
                value = str(sorted(str(v) for v in val))[:8000]
            elif callable(val):
                t = "function"
                try:
                    import inspect as _insp
                    sig = str(_insp.signature(val))
                    preview = name + sig
                    del _insp
                except Exception:
                    preview = "<function " + name + ">"
                value = preview
            elif hasattr(val,'__module__') and not callable(val):
                t = "module"
                preview = "<module '" + str(getattr(val,'__name__',name)) + "'>"
                value = preview
            else:
                value = repr(val)[:8000]
                preview = value[:80]
        except Exception as __se__:
            preview = "<err: " + str(__se__) + ">"
            value = preview

        result = {"name": name, "type": t, "preview": preview, "value": value}
        if size is not None: result["size"] = size
        if dtype is not None: result["dtype"] = dtype
        return result

    __skip_names__ = {
        '__builtins__','__name__','__doc__','__package__','__loader__',
        '__spec__','__import__','__stdout__','__stderr__','_Capture',
        '__is_installed__','__mark_installed__','__pip_msg__',
        '__code_to_analyze__','__emit_var__','__json__','__serialize_var__',
        '__skip_names__','sys','io',
    }

    for __vk__, __vv__ in list(globals().items()):
        if __vk__.startswith('_') or __vk__ in __skip_names__:
            continue
        try:
            __emit_var__(__json__.dumps(__serialize_var__(__vk__, __vv__), ensure_ascii=False))
        except Exception:
            pass
except Exception as _pip_err:
    _err_str = str(_pip_err)
    if 'PackageNotFoundError' in _err_str or "Can't find" in _err_str or 'not found' in _err_str.lower():
        __pip_msg__(f'[pip-unavailable] {_err_str}\n')
finally:
    try:
        _g = globals()
        for _n in ['__json__','__serialize_var__','__skip_names__','__emit_var__','__vk__','__vv__','_g','_n']:
            try: del _g[_n]
            except Exception: pass
    except Exception:
        pass
`;

// ─── Pyodide load ─────────────────────────────────────────────────────────────

async function getPyodide(): Promise<PyodideInstance> {
  if (pyodide) return pyodide;
  if (loadPromise) return loadPromise;

  self.postMessage({ type: "loading", progress: 0 } satisfies PyRunnerResult);

  loadPromise = (async () => {
    // S448: reidrata i package già installati da sessioni/respawn precedenti
    await loadPkgCacheFromOPFS();

    // ESM module workers non supportano importScripts — usa dynamic import
    // @vite-ignore evita che Vite tenti di bundlare l'URL CDN remoto
    const { loadPyodide } = await import(/* @vite-ignore */ `${PYODIDE_CDN}pyodide.mjs`);
    self.postMessage({ type: "loading", progress: 30 } satisfies PyRunnerResult);

    // S448: micropip precaricato in parallelo al bootstrap — elimina round-trip CDN separato
    const py = await loadPyodide({ indexURL: PYODIDE_CDN, packages: ["micropip"] });
    self.postMessage({ type: "loading", progress: 80 } satisfies PyRunnerResult);

    pyodide = py;
    self.postMessage({ type: "ready" } satisfies PyRunnerResult);
    return py;
  })();

  return loadPromise;
}

// ─── S45/S70: auto-install imports con cache ──────────────────────────────────

async function autoInstallImports(
  py: PyodideInstance,
  code: string,
  id: string,
): Promise<void> {
  // Step 1 — standard Pyodide packages (Pyodide li cachea internamente)
  try {
    await py.loadPackagesFromImports(code);
  } catch {
    // non-fatal
  }

  // Step 2 — micropip per pacchetti PyPI puri non inclusi in Pyodide
  try {
    py.globals.set("__code_to_analyze__", code);
    py.globals.set("__is_installed__", (pkg: string) => _installedPkgs.has(pkg));
    py.globals.set("__mark_installed__", (pkg: string) => {
      _installedPkgs.add(pkg);
      savePkgCacheToOPFS(); // S448: aggiorna OPFS cache dopo ogni install
    });
    py.globals.set("__pip_msg__", (text: string) => {
      self.postMessage({ type: "stdout", id, text } satisfies PyRunnerResult);
    });

    await py.runPythonAsync(`
import sys as _sys
try:
    import micropip as _micropip
    import ast as _ast
    _tree = _ast.parse(__code_to_analyze__)
    _missing: list[str] = []
    for _node in _ast.walk(_tree):
        if isinstance(_node, _ast.Import):
            for _alias in _node.names:
                _pkg = _alias.name.split(".")[0]
                try:
                    __import__(_pkg)
                except ImportError:
                    if _pkg not in _missing:
                        _missing.append(_pkg)
        elif isinstance(_node, _ast.ImportFrom):
            if _node.module:
                _pkg = _node.module.split(".")[0]
                try:
                    __import__(_pkg)
                except ImportError:
                    if _pkg not in _missing:
                        _missing.append(_pkg)
    _installed_count = 0
    _cached_count = 0
    for _pkg in _missing:
        if __is_installed__(_pkg):
            __pip_msg__(f"[pip] \\u2713 {_pkg} (cache)\\n")
            _cached_count += 1
        else:
            __pip_msg__(f"[pip] Installo: {_pkg}\\u2026\\n")
            await _micropip.install(_pkg, keep_going=True)
            __mark_installed__(_pkg)
            _installed_count += 1
    if _installed_count > 0:
        __pip_msg__(f"[pip] \\u2713 {_installed_count} pacchett{'o' if _installed_count == 1 else 'i'} installat{'o' if _installed_count == 1 else 'i'}\\n")
except Exception:
    pass
finally:
    try: del __code_to_analyze__, __is_installed__, __mark_installed__, __pip_msg__
    except Exception: pass
`);
  } catch {
    // non-fatal
  }
}

// ─── S71: estrazione variabili globali post-run ───────────────────────────────

async function extractAndSendVars(py: PyodideInstance, id: string): Promise<void> {
  const vars: PythonVarData[] = [];
  try {
    py.globals.set("__emit_var__", (varJson: string) => {
      try {
        vars.push(JSON.parse(varJson) as PythonVarData);
      } catch {
        // non-fatal: skip malformed var
      }
    });
    await py.runPythonAsync(EXTRACT_GLOBALS_CODE);
    if (vars.length > 0) {
      self.postMessage({ type: "vars", id, vars } satisfies PyRunnerResult);
    }
  } catch {
    // non-fatal: vars extraction failure non blocca l'esecuzione
  }
}

// ─── Message handler ──────────────────────────────────────────────────────────

self.onmessage = async (e: MessageEvent<PyRunnerMsg>) => {
  const msg = e.data;

  if (msg.type === "ping") {
    self.postMessage({ type: "ready" } satisfies PyRunnerResult);
    return;
  }

  if (msg.type === "cancel") {
    const ctx = running.get(msg.id);
    if (ctx) ctx.cancelled = true;
    return;
  }

  if (msg.type === "run") {
    const { id, code, timeout = 30_000, packages = [] } = msg;
    const ctx = { cancelled: false };
    running.set(id, ctx);
    const start = Date.now();

    let timedOut = false;
    const timer = setTimeout(() => {
      timedOut = true;
      ctx.cancelled = true;
      self.postMessage({ type: "stderr", id, text: "[timeout] Python execution exceeded " + timeout + "ms\n" } satisfies PyRunnerResult);
      self.postMessage({ type: "done", id, exitCode: 124, time: Date.now() - start } satisfies PyRunnerResult);
    }, timeout);

    try {
      const py = await getPyodide();

      if (ctx.cancelled) { clearTimeout(timer); running.delete(id); return; }

      // S45/S70: auto-detect e installa imports (standard Pyodide + micropip con cache)
      await autoInstallImports(py, code, id);

      if (ctx.cancelled) { clearTimeout(timer); running.delete(id); return; }

      // Pacchetti espliciti richiesti dal caller (retrocompatibilità)
      if (packages.length > 0) {
        const toInstall = packages.filter(p => !_installedPkgs.has(p));
        const cached    = packages.filter(p =>  _installedPkgs.has(p));
        if (cached.length > 0) {
          self.postMessage({ type: "stdout", id, text: `[pip] ✓ ${cached.join(", ")} (cache)\n` } satisfies PyRunnerResult);
        }
        if (toInstall.length > 0) {
          self.postMessage({ type: "stdout", id, text: `[pip] Installo: ${toInstall.join(", ")}…\n` } satisfies PyRunnerResult);
          await py.loadPackage(toInstall);
          for (const p of toInstall) _installedPkgs.add(p);
          savePkgCacheToOPFS(); // S448: persiste anche i package espliciti in OPFS
        }
      }

      py.globals.set("__stdout__", (text: string) => {
        if (!ctx.cancelled) self.postMessage({ type: "stdout", id, text } satisfies PyRunnerResult);
      });
      py.globals.set("__stderr__", (text: string) => {
        if (!ctx.cancelled) self.postMessage({ type: "stderr", id, text } satisfies PyRunnerResult);
      });

      const wrapped = `
import sys, io

class _Capture(io.StringIO):
    def __init__(self, fn):
        super().__init__()
        self._fn = fn
    def write(self, s):
        if s:
            self._fn(s)
        return len(s)
    def flush(self): pass

sys.stdout = _Capture(__stdout__)
sys.stderr = _Capture(__stderr__)

${code}
`;
      await py.runPythonAsync(wrapped);

      if (!timedOut && !ctx.cancelled) {
        // S71: estrai variabili globali e inviale al main thread
        await extractAndSendVars(py, id);
        self.postMessage({ type: "done", id, exitCode: 0, time: Date.now() - start } satisfies PyRunnerResult);
      }
    } catch (err) {
      if (!timedOut) {
        const errMsg = err instanceof Error ? err.message : String(err);
        self.postMessage({ type: "stderr", id, text: errMsg + "\n" } satisfies PyRunnerResult);
        // S71: estrai anche in caso di errore parziale (alcune var potrebbero essere definite)
        try {
          if (pyodide) await extractAndSendVars(pyodide, id);
        } catch { /* non-fatal */ }
        self.postMessage({ type: "done", id, exitCode: 1, time: Date.now() - start } satisfies PyRunnerResult);
      }
    } finally {
      clearTimeout(timer);
      running.delete(id);
    }
  }
};