/**
 * sx-platform.js — Thin JS platform layer for the OCaml SX WASM engine.
 *
 * This file provides browser-native primitives (DOM, fetch, timers, etc.)
 * to the WASM-compiled OCaml CEK machine. It:
 *   1. Loads the WASM module (SxKernel)
 *   2. Registers ~80 native browser functions via registerNative
 *   3. Loads web adapters (.sx files) into the engine
 *   4. Exports the public Sx API
 *
 * Both wasm_of_ocaml and js_of_ocaml targets bind to this same layer.
 */

(function(global) {
  "use strict";

  function initPlatform() {
  var K = global.SxKernel;
  if (!K) {
    // WASM loader is async — wait and retry
    setTimeout(initPlatform, 20);
    return;
  }

  var _hasDom = typeof document !== "undefined";
  var NIL = null;
  var SVG_NS = "http://www.w3.org/2000/svg";

  // =========================================================================
  // Helper: wrap SX lambda for use as JS callback
  // =========================================================================

  function wrapLambda(fn) {
    // For now, SX lambdas from registerNative are opaque — we can't call them
    // directly from JS. They need to go through the engine.
    // TODO: add callLambda API to SxKernel
    return fn;
  }

  // =========================================================================
  // 1. DOM Creation & Manipulation
  // =========================================================================

  K.registerNative("dom-create-element", function(args) {
    if (!_hasDom) return NIL;
    var tag = args[0], ns = args[1];
    if (ns && ns !== NIL) return document.createElementNS(ns, tag);
    return document.createElement(tag);
  });

  K.registerNative("create-text-node", function(args) {
    return _hasDom ? document.createTextNode(args[0] || "") : NIL;
  });

  K.registerNative("create-comment", function(args) {
    return _hasDom ? document.createComment(args[0] || "") : NIL;
  });

  K.registerNative("create-fragment", function(_args) {
    return _hasDom ? document.createDocumentFragment() : NIL;
  });

  K.registerNative("dom-clone", function(args) {
    var node = args[0];
    return node && node.cloneNode ? node.cloneNode(true) : node;
  });

  K.registerNative("dom-parse-html", function(args) {
    if (!_hasDom) return NIL;
    var tpl = document.createElement("template");
    tpl.innerHTML = args[0] || "";
    return tpl.content;
  });

  K.registerNative("dom-parse-html-document", function(args) {
    if (!_hasDom) return NIL;
    var parser = new DOMParser();
    return parser.parseFromString(args[0] || "", "text/html");
  });

  // =========================================================================
  // 2. DOM Queries
  // =========================================================================

  K.registerNative("dom-query", function(args) {
    return _hasDom ? document.querySelector(args[0]) || NIL : NIL;
  });

  K.registerNative("dom-query-all", function(args) {
    var root = args[0] || (_hasDom ? document : null);
    if (!root || !root.querySelectorAll) return [];
    return Array.prototype.slice.call(root.querySelectorAll(args[1] || args[0]));
  });

  K.registerNative("dom-query-by-id", function(args) {
    return _hasDom ? document.getElementById(args[0]) || NIL : NIL;
  });

  K.registerNative("dom-body", function(_args) {
    return _hasDom ? document.body : NIL;
  });

  K.registerNative("dom-ensure-element", function(args) {
    if (!_hasDom) return NIL;
    var sel = args[0];
    var el = document.querySelector(sel);
    if (el) return el;
    if (sel.charAt(0) === "#") {
      el = document.createElement("div");
      el.id = sel.slice(1);
      document.body.appendChild(el);
      return el;
    }
    return NIL;
  });

  // =========================================================================
  // 3. DOM Attributes
  // =========================================================================

  K.registerNative("dom-get-attr", function(args) {
    var el = args[0], name = args[1];
    if (!el || !el.getAttribute) return NIL;
    var v = el.getAttribute(name);
    return v === null ? NIL : v;
  });

  K.registerNative("dom-set-attr", function(args) {
    var el = args[0], name = args[1], val = args[2];
    if (el && el.setAttribute) el.setAttribute(name, val);
    return NIL;
  });

  K.registerNative("dom-remove-attr", function(args) {
    if (args[0] && args[0].removeAttribute) args[0].removeAttribute(args[1]);
    return NIL;
  });

  K.registerNative("dom-has-attr?", function(args) {
    return !!(args[0] && args[0].hasAttribute && args[0].hasAttribute(args[1]));
  });

  K.registerNative("dom-attr-list", function(args) {
    var el = args[0];
    if (!el || !el.attributes) return [];
    var r = [];
    for (var i = 0; i < el.attributes.length; i++) {
      r.push([el.attributes[i].name, el.attributes[i].value]);
    }
    return r;
  });

  // =========================================================================
  // 4. DOM Content
  // =========================================================================

  K.registerNative("dom-text-content", function(args) {
    var el = args[0];
    return el ? el.textContent || el.nodeValue || "" : "";
  });

  K.registerNative("dom-set-text-content", function(args) {
    var el = args[0], s = args[1];
    if (el) {
      if (el.nodeType === 3 || el.nodeType === 8) el.nodeValue = s;
      else el.textContent = s;
    }
    return NIL;
  });

  K.registerNative("dom-inner-html", function(args) {
    return args[0] && args[0].innerHTML != null ? args[0].innerHTML : "";
  });

  K.registerNative("dom-set-inner-html", function(args) {
    if (args[0]) args[0].innerHTML = args[1] || "";
    return NIL;
  });

  K.registerNative("dom-insert-adjacent-html", function(args) {
    var el = args[0], pos = args[1], html = args[2];
    if (el && el.insertAdjacentHTML) el.insertAdjacentHTML(pos, html);
    return NIL;
  });

  K.registerNative("dom-body-inner-html", function(args) {
    var doc = args[0];
    return doc && doc.body ? doc.body.innerHTML : "";
  });

  // =========================================================================
  // 5. DOM Structure & Navigation
  // =========================================================================

  K.registerNative("dom-parent", function(args) { return args[0] ? args[0].parentNode || NIL : NIL; });
  K.registerNative("dom-first-child", function(args) { return args[0] ? args[0].firstChild || NIL : NIL; });
  K.registerNative("dom-next-sibling", function(args) { return args[0] ? args[0].nextSibling || NIL : NIL; });
  K.registerNative("dom-id", function(args) { return args[0] && args[0].id ? args[0].id : NIL; });
  K.registerNative("dom-node-type", function(args) { return args[0] ? args[0].nodeType : 0; });
  K.registerNative("dom-node-name", function(args) { return args[0] ? args[0].nodeName : ""; });
  K.registerNative("dom-tag-name", function(args) { return args[0] && args[0].tagName ? args[0].tagName : ""; });

  K.registerNative("dom-child-list", function(args) {
    var el = args[0];
    if (!el || !el.childNodes) return [];
    return Array.prototype.slice.call(el.childNodes);
  });

  K.registerNative("dom-child-nodes", function(args) {
    var el = args[0];
    if (!el || !el.childNodes) return [];
    return Array.prototype.slice.call(el.childNodes);
  });

  // =========================================================================
  // 6. DOM Insertion & Removal
  // =========================================================================

  K.registerNative("dom-append", function(args) {
    var parent = args[0], child = args[1];
    if (parent && child) parent.appendChild(child);
    return NIL;
  });

  K.registerNative("dom-prepend", function(args) {
    var parent = args[0], child = args[1];
    if (parent && child) parent.insertBefore(child, parent.firstChild);
    return NIL;
  });

  K.registerNative("dom-insert-before", function(args) {
    var parent = args[0], node = args[1], ref = args[2];
    if (parent && node) parent.insertBefore(node, ref || null);
    return NIL;
  });

  K.registerNative("dom-insert-after", function(args) {
    var ref = args[0], node = args[1];
    if (ref && ref.parentNode && node) {
      ref.parentNode.insertBefore(node, ref.nextSibling);
    }
    return NIL;
  });

  K.registerNative("dom-remove", function(args) {
    var node = args[0];
    if (node && node.parentNode) node.parentNode.removeChild(node);
    return NIL;
  });

  K.registerNative("dom-remove-child", function(args) {
    var parent = args[0], child = args[1];
    if (parent && child && child.parentNode === parent) parent.removeChild(child);
    return NIL;
  });

  K.registerNative("dom-replace-child", function(args) {
    var parent = args[0], newC = args[1], oldC = args[2];
    if (parent && newC && oldC) parent.replaceChild(newC, oldC);
    return NIL;
  });

  K.registerNative("dom-remove-children-after", function(args) {
    var marker = args[0];
    if (!marker || !marker.parentNode) return NIL;
    var parent = marker.parentNode;
    while (marker.nextSibling) parent.removeChild(marker.nextSibling);
    return NIL;
  });

  K.registerNative("dom-append-to-head", function(args) {
    if (_hasDom && args[0]) document.head.appendChild(args[0]);
    return NIL;
  });

  // =========================================================================
  // 7. DOM Type Checks
  // =========================================================================

  K.registerNative("dom-is-fragment?", function(args) { return args[0] ? args[0].nodeType === 11 : false; });
  K.registerNative("dom-is-child-of?", function(args) { return !!(args[1] && args[0] && args[0].parentNode === args[1]); });
  K.registerNative("dom-is-active-element?", function(args) { return _hasDom && args[0] === document.activeElement; });
  K.registerNative("dom-is-input-element?", function(args) {
    if (!args[0] || !args[0].tagName) return false;
    var t = args[0].tagName;
    return t === "INPUT" || t === "TEXTAREA" || t === "SELECT";
  });

  // =========================================================================
  // 8. DOM Styles & Classes
  // =========================================================================

  K.registerNative("dom-get-style", function(args) {
    return args[0] && args[0].style ? args[0].style[args[1]] || "" : "";
  });

  K.registerNative("dom-set-style", function(args) {
    if (args[0] && args[0].style) args[0].style[args[1]] = args[2];
    return NIL;
  });

  K.registerNative("dom-add-class", function(args) {
    if (args[0] && args[0].classList) args[0].classList.add(args[1]);
    return NIL;
  });

  K.registerNative("dom-remove-class", function(args) {
    if (args[0] && args[0].classList) args[0].classList.remove(args[1]);
    return NIL;
  });

  K.registerNative("dom-has-class?", function(args) {
    return !!(args[0] && args[0].classList && args[0].classList.contains(args[1]));
  });

  // =========================================================================
  // 9. DOM Properties & Data
  // =========================================================================

  K.registerNative("dom-get-prop", function(args) { return args[0] ? args[0][args[1]] : NIL; });
  K.registerNative("dom-set-prop", function(args) { if (args[0]) args[0][args[1]] = args[2]; return NIL; });

  K.registerNative("dom-set-data", function(args) {
    var el = args[0], key = args[1], val = args[2];
    if (el) { if (!el._sxData) el._sxData = {}; el._sxData[key] = val; }
    return NIL;
  });

  K.registerNative("dom-get-data", function(args) {
    var el = args[0], key = args[1];
    return (el && el._sxData) ? (el._sxData[key] != null ? el._sxData[key] : NIL) : NIL;
  });

  K.registerNative("dom-call-method", function(args) {
    var obj = args[0], method = args[1];
    var callArgs = args.slice(2);
    if (obj && typeof obj[method] === "function") {
      try { return obj[method].apply(obj, callArgs); }
      catch(e) { return NIL; }
    }
    return NIL;
  });

  // =========================================================================
  // 10. DOM Events
  // =========================================================================

  K.registerNative("dom-listen", function(args) {
    var el = args[0], name = args[1], handler = args[2];
    if (!_hasDom || !el) return function() {};

    // handler is a wrapped SX lambda (JS function with __sx_handle).
    // Wrap it to:
    //   - Pass the event object as arg (or no args for 0-arity handlers)
    //   - Catch errors from the CEK machine
    var arity = K.fnArity(handler);
    var wrapped;
    if (arity === 0) {
      wrapped = function(_e) {
        try { K.callFn(handler, []); }
        catch(err) { console.error("[sx] event handler error:", name, err); }
      };
    } else {
      wrapped = function(e) {
        try { K.callFn(handler, [e]); }
        catch(err) { console.error("[sx] event handler error:", name, err); }
      };
    }
    el.addEventListener(name, wrapped);
    return function() { el.removeEventListener(name, wrapped); };
  });

  K.registerNative("dom-dispatch", function(args) {
    if (!_hasDom || !args[0]) return false;
    var evt = new CustomEvent(args[1], { bubbles: true, cancelable: true, detail: args[2] || {} });
    return args[0].dispatchEvent(evt);
  });

  K.registerNative("event-detail", function(args) {
    return (args[0] && args[0].detail != null) ? args[0].detail : NIL;
  });

  // =========================================================================
  // 11. Browser Navigation & History
  // =========================================================================

  K.registerNative("browser-location-href", function(_args) {
    return typeof location !== "undefined" ? location.href : "";
  });

  K.registerNative("browser-same-origin?", function(args) {
    try { return new URL(args[0], location.href).origin === location.origin; }
    catch (e) { return true; }
  });

  K.registerNative("browser-push-state", function(args) {
    if (typeof history !== "undefined") {
      try { history.pushState({ sxUrl: args[0], scrollY: typeof window !== "undefined" ? window.scrollY : 0 }, "", args[0]); }
      catch (e) {}
    }
    return NIL;
  });

  K.registerNative("browser-replace-state", function(args) {
    if (typeof history !== "undefined") {
      try { history.replaceState({ sxUrl: args[0], scrollY: typeof window !== "undefined" ? window.scrollY : 0 }, "", args[0]); }
      catch (e) {}
    }
    return NIL;
  });

  K.registerNative("browser-navigate", function(args) {
    if (typeof location !== "undefined") location.assign(args[0]);
    return NIL;
  });

  K.registerNative("browser-reload", function(_args) {
    if (typeof location !== "undefined") location.reload();
    return NIL;
  });

  K.registerNative("browser-scroll-to", function(args) {
    if (typeof window !== "undefined") window.scrollTo(args[0] || 0, args[1] || 0);
    return NIL;
  });

  K.registerNative("browser-media-matches?", function(args) {
    if (typeof window === "undefined") return false;
    return window.matchMedia(args[0]).matches;
  });

  K.registerNative("browser-confirm", function(args) {
    if (typeof window === "undefined") return false;
    return window.confirm(args[0]);
  });

  K.registerNative("browser-prompt", function(args) {
    if (typeof window === "undefined") return NIL;
    var r = window.prompt(args[0]);
    return r === null ? NIL : r;
  });

  // =========================================================================
  // 12. Timers
  // =========================================================================

  K.registerNative("set-timeout", function(args) {
    var fn = args[0], ms = args[1] || 0;
    var cb = (typeof fn === "function" && fn.__sx_handle != null)
      ? function() { try { K.callFn(fn, []); } catch(e) { console.error("[sx] timeout error:", e); } }
      : fn;
    return setTimeout(cb, ms);
  });

  K.registerNative("set-interval", function(args) {
    var fn = args[0], ms = args[1] || 1000;
    var cb = (typeof fn === "function" && fn.__sx_handle != null)
      ? function() { try { K.callFn(fn, []); } catch(e) { console.error("[sx] interval error:", e); } }
      : fn;
    return setInterval(cb, ms);
  });

  K.registerNative("clear-timeout", function(args) { clearTimeout(args[0]); return NIL; });
  K.registerNative("clear-interval", function(args) { clearInterval(args[0]); return NIL; });
  K.registerNative("now-ms", function(_args) {
    return (typeof performance !== "undefined") ? performance.now() : Date.now();
  });

  K.registerNative("request-animation-frame", function(args) {
    var fn = args[0];
    var cb = (typeof fn === "function" && fn.__sx_handle != null)
      ? function() { try { K.callFn(fn, []); } catch(e) { console.error("[sx] raf error:", e); } }
      : fn;
    if (typeof requestAnimationFrame !== "undefined") requestAnimationFrame(cb);
    else setTimeout(cb, 16);
    return NIL;
  });

  // =========================================================================
  // 13. Promises
  // =========================================================================

  K.registerNative("promise-resolve", function(args) { return Promise.resolve(args[0]); });

  K.registerNative("promise-then", function(args) {
    var p = args[0];
    if (!p || !p.then) return p;
    var onResolve = function(v) { return K.callFn(args[1], [v]); };
    var onReject = args[2] ? function(e) { return K.callFn(args[2], [e]); } : undefined;
    return onReject ? p.then(onResolve, onReject) : p.then(onResolve);
  });

  K.registerNative("promise-catch", function(args) {
    if (!args[0] || !args[0].catch) return args[0];
    return args[0].catch(function(e) { return K.callFn(args[1], [e]); });
  });

  K.registerNative("promise-delayed", function(args) {
    return new Promise(function(resolve) {
      setTimeout(function() { resolve(args[1]); }, args[0]);
    });
  });

  // =========================================================================
  // 14. Abort Controllers
  // =========================================================================

  var _controllers = typeof WeakMap !== "undefined" ? new WeakMap() : null;
  var _targetControllers = typeof WeakMap !== "undefined" ? new WeakMap() : null;

  K.registerNative("new-abort-controller", function(_args) {
    return typeof AbortController !== "undefined" ? new AbortController() : { signal: null, abort: function() {} };
  });

  K.registerNative("abort-previous", function(args) {
    if (_controllers) { var prev = _controllers.get(args[0]); if (prev) prev.abort(); }
    return NIL;
  });

  K.registerNative("track-controller", function(args) {
    if (_controllers) _controllers.set(args[0], args[1]);
    return NIL;
  });

  K.registerNative("abort-previous-target", function(args) {
    if (_targetControllers) { var prev = _targetControllers.get(args[0]); if (prev) prev.abort(); }
    return NIL;
  });

  K.registerNative("track-controller-target", function(args) {
    if (_targetControllers) _targetControllers.set(args[0], args[1]);
    return NIL;
  });

  K.registerNative("controller-signal", function(args) { return args[0] ? args[0].signal : NIL; });
  K.registerNative("is-abort-error", function(args) { return args[0] && args[0].name === "AbortError"; });

  // =========================================================================
  // 15. Fetch
  // =========================================================================

  K.registerNative("fetch-request", function(args) {
    var config = args[0], successFn = args[1], errorFn = args[2];
    var opts = { method: config.method, headers: config.headers };
    if (config.signal) opts.signal = config.signal;
    if (config.body && config.method !== "GET") opts.body = config.body;
    if (config["cross-origin"]) opts.credentials = "include";

    return fetch(config.url, opts).then(function(resp) {
      return resp.text().then(function(text) {
        var getHeader = function(name) {
          var v = resp.headers.get(name);
          return v === null ? NIL : v;
        };
        return K.callFn(successFn, [resp.ok, resp.status, getHeader, text]);
      });
    }).catch(function(err) {
      return K.callFn(errorFn, [err]);
    });
  });

  K.registerNative("csrf-token", function(_args) {
    if (!_hasDom) return NIL;
    var m = document.querySelector('meta[name="csrf-token"]');
    return m ? m.getAttribute("content") : NIL;
  });

  K.registerNative("is-cross-origin", function(args) {
    try {
      var h = new URL(args[0], location.href).hostname;
      return h !== location.hostname &&
        (h.indexOf(".rose-ash.com") >= 0 || h.indexOf(".localhost") >= 0);
    } catch (e) { return false; }
  });

  // =========================================================================
  // 16. localStorage
  // =========================================================================

  K.registerNative("local-storage-get", function(args) {
    try { var v = localStorage.getItem(args[0]); return v === null ? NIL : v; }
    catch(e) { return NIL; }
  });

  K.registerNative("local-storage-set", function(args) {
    try { localStorage.setItem(args[0], args[1]); } catch(e) {}
    return NIL;
  });

  K.registerNative("local-storage-remove", function(args) {
    try { localStorage.removeItem(args[0]); } catch(e) {}
    return NIL;
  });

  // =========================================================================
  // 17. Document Head & Title
  // =========================================================================

  K.registerNative("set-document-title", function(args) {
    if (_hasDom) document.title = args[0] || "";
    return NIL;
  });

  K.registerNative("remove-head-element", function(args) {
    if (_hasDom) {
      var el = document.head.querySelector(args[0]);
      if (el) el.remove();
    }
    return NIL;
  });

  // =========================================================================
  // 18. Logging
  // =========================================================================

  K.registerNative("log-info", function(args) { console.log("[sx]", args[0]); return NIL; });
  K.registerNative("log-warn", function(args) { console.warn("[sx]", args[0]); return NIL; });
  K.registerNative("log-error", function(args) { console.error("[sx]", args[0]); return NIL; });

  // =========================================================================
  // 19. JSON
  // =========================================================================

  K.registerNative("json-parse", function(args) {
    try { return JSON.parse(args[0]); } catch(e) { return {}; }
  });

  K.registerNative("try-parse-json", function(args) {
    try { return JSON.parse(args[0]); } catch(e) { return NIL; }
  });

  // =========================================================================
  // 20. Processing markers
  // =========================================================================

  K.registerNative("mark-processed!", function(args) {
    var el = args[0], key = args[1] || "sx";
    if (el) { if (!el._sxProcessed) el._sxProcessed = {}; el._sxProcessed[key] = true; }
    return NIL;
  });

  K.registerNative("is-processed?", function(args) {
    var el = args[0], key = args[1] || "sx";
    return !!(el && el._sxProcessed && el._sxProcessed[key]);
  });

  // =========================================================================
  // Public Sx API (wraps SxKernel for compatibility with existing code)
  // =========================================================================

  var Sx = {
    // Core (delegated to WASM engine)
    parse: K.parse,
    eval: K.eval,
    evalExpr: K.evalExpr,
    load: K.load,
    loadSource: K.loadSource,
    renderToHtml: K.renderToHtml,
    typeOf: K.typeOf,
    inspect: K.inspect,
    engine: K.engine,

    // Will be populated after web adapters load:
    // mount, hydrate, processElements, etc.
  };

  global.Sx = Sx;
  global.SxKernel = K;  // Keep kernel available for direct access

  console.log("[sx-platform] registered, engine:", K.engine());

  } // end initPlatform

  initPlatform();

})(typeof globalThis !== "undefined" ? globalThis : this);