/**
 * sx-platform.js — Browser platform layer for the SX WASM kernel.
 *
 * Registers the 8 FFI host primitives and loads web adapter .sx files.
 * This is the only JS needed beyond the WASM kernel itself.
 *
 * Usage:
 *   <script src="sx_browser.bc.wasm.js"></script>
 *   <script src="sx-platform.js"></script>
 *
 * Or for js_of_ocaml mode:
 *   <script src="sx_browser.bc.js"></script>
 *   <script src="sx-platform.js"></script>
 */

(function() {
  "use strict";

  function boot(K) {

  // ================================================================
  // 8 FFI Host Primitives
  // ================================================================

  K.registerNative("host-global", function(args) {
    var name = args[0];
    if (typeof globalThis !== "undefined" && name in globalThis) return globalThis[name];
    if (typeof window !== "undefined" && name in window) return window[name];
    return null;
  });

  K.registerNative("host-get", function(args) {
    var obj = args[0], prop = args[1];
    if (obj == null) return null;
    var v = obj[prop];
    return v === undefined ? null : v;
  });

  K.registerNative("host-set!", function(args) {
    var obj = args[0], prop = args[1], val = args[2];
    if (obj != null) obj[prop] = val;
  });

  K.registerNative("host-call", function(args) {
    var obj = args[0], method = args[1];
    var callArgs = [];
    for (var i = 2; i < args.length; i++) callArgs.push(args[i]);
    if (obj == null) {
      // Global function call
      var fn = typeof globalThis !== "undefined" ? globalThis[method] : window[method];
      if (typeof fn === "function") return fn.apply(null, callArgs);
      return null;
    }
    if (typeof obj[method] === "function") {
      try { return obj[method].apply(obj, callArgs); }
      catch(e) { console.error("[sx] host-call error:", e); return null; }
    }
    return null;
  });

  K.registerNative("host-new", function(args) {
    var name = args[0];
    var cArgs = args.slice(1);
    var Ctor = typeof globalThis !== "undefined" ? globalThis[name] : window[name];
    if (typeof Ctor !== "function") return null;
    switch (cArgs.length) {
      case 0: return new Ctor();
      case 1: return new Ctor(cArgs[0]);
      case 2: return new Ctor(cArgs[0], cArgs[1]);
      case 3: return new Ctor(cArgs[0], cArgs[1], cArgs[2]);
      default: return new Ctor(cArgs[0], cArgs[1], cArgs[2], cArgs[3]);
    }
  });

  K.registerNative("host-callback", function(args) {
    var fn = args[0];
    // Native JS function — pass through
    if (typeof fn === "function") return fn;
    // SX callable (has __sx_handle) — wrap as JS function
    if (fn && fn.__sx_handle !== undefined) {
      return function() {
        var a = Array.prototype.slice.call(arguments);
        return K.callFn(fn, a);
      };
    }
    return function() {};
  });

  K.registerNative("host-typeof", function(args) {
    var obj = args[0];
    if (obj == null) return "nil";
    if (obj instanceof Element) return "element";
    if (obj instanceof Text) return "text";
    if (obj instanceof DocumentFragment) return "fragment";
    if (obj instanceof Document) return "document";
    if (obj instanceof Event) return "event";
    if (obj instanceof Promise) return "promise";
    if (obj instanceof AbortController) return "abort-controller";
    return typeof obj;
  });

  K.registerNative("host-await", function(args) {
    var promise = args[0], callback = args[1];
    if (promise && typeof promise.then === "function") {
      var cb;
      if (typeof callback === "function") cb = callback;
      else if (callback && callback.__sx_handle !== undefined)
        cb = function(v) { return K.callFn(callback, [v]); };
      else cb = function() {};
      promise.then(cb);
    }
  });

  // ================================================================
  // Constants expected by .sx files
  // ================================================================

  K.eval('(define SX_VERSION "wasm-1.0")');
  K.eval('(define SX_ENGINE "ocaml-vm-wasm")');
  K.eval('(define parse sx-parse)');
  K.eval('(define serialize sx-serialize)');

  // ================================================================
  // DOM query helpers used by boot.sx / orchestration.sx
  // (These are JS-native in the transpiled bundle; here via FFI.)
  // ================================================================

  K.registerNative("query-sx-scripts", function(args) {
    var root = (args[0] && args[0] !== null) ? args[0] : document;
    if (typeof root.querySelectorAll !== "function") root = document;
    return Array.prototype.slice.call(root.querySelectorAll('script[type="text/sx"]'));
  });

  K.registerNative("query-page-scripts", function(args) {
    return Array.prototype.slice.call(document.querySelectorAll('script[type="text/sx-pages"]'));
  });

  K.registerNative("query-component-scripts", function(args) {
    var root = (args[0] && args[0] !== null) ? args[0] : document;
    if (typeof root.querySelectorAll !== "function") root = document;
    return Array.prototype.slice.call(root.querySelectorAll('script[type="text/sx"][data-components]'));
  });

  // localStorage
  K.registerNative("local-storage-get", function(args) {
    try { var v = localStorage.getItem(args[0]); return v === null ? null : v; }
    catch(e) { return null; }
  });
  K.registerNative("local-storage-set", function(args) {
    try { localStorage.setItem(args[0], args[1]); } catch(e) {}
  });
  K.registerNative("local-storage-remove", function(args) {
    try { localStorage.removeItem(args[0]); } catch(e) {}
  });

  // log-info/log-warn defined in browser.sx; log-error as native fallback
  K.registerNative("log-error", function(args) { console.error.apply(console, ["[sx]"].concat(args)); });

  // Cookie access (browser-side)
  K.registerNative("get-cookie", function(args) {
    var name = args[0];
    var match = document.cookie.match(new RegExp('(?:^|; )' + name.replace(/[.*+?^${}()|[\]\\]/g, '\\$&') + '=([^;]*)'));
    return match ? decodeURIComponent(match[1]) : null;
  });
  K.registerNative("set-cookie", function(args) {
    document.cookie = args[0] + "=" + encodeURIComponent(args[1] || "") + ";path=/;max-age=31536000;SameSite=Lax";
  });

  // ================================================================
  // Load SX web libraries and adapters
  // ================================================================

  // Load order follows dependency graph:
  //   1. Core spec files (parser, render, primitives already compiled into WASM kernel)
  //   2. Spec modules: signals, deps, router, page-helpers
  //   3. Bytecode compiler + VM (for JIT in browser)
  //   4. Web libraries: dom.sx, browser.sx (built on 8 FFI primitives)
  //   5. Web adapters: adapter-html, adapter-sx, adapter-dom
  //   6. Web framework: engine, orchestration, boot

  var _baseUrl = "";

  // Detect base URL and cache-bust params from current script tag.
  // _cacheBust comes from the script's own ?v= query string (used for .sx source fallback).
  // _sxbcCacheBust comes from data-sxbc-hash attribute — a separate content hash
  // covering all .sxbc files so each file gets its own correct cache buster.
  var _cacheBust = "";
  var _sxbcCacheBust = "";
  (function() {
    if (typeof document !== "undefined") {
      var scripts = document.getElementsByTagName("script");
      for (var i = scripts.length - 1; i >= 0; i--) {
        var src = scripts[i].src || "";
        if (src.indexOf("sx-platform") !== -1) {
          _baseUrl = src.substring(0, src.lastIndexOf("/") + 1);
          var qi = src.indexOf("?");
          if (qi !== -1) _cacheBust = src.substring(qi);
          var sxbcHash = scripts[i].getAttribute("data-sxbc-hash");
          if (sxbcHash) _sxbcCacheBust = "?v=" + sxbcHash;
          break;
        }
      }
    }
  })();

  /**
   * Deserialize type-tagged JSON constant back to JS value for loadModule.
   */
  function deserializeConstant(c) {
    if (!c || !c.t) return null;
    switch (c.t) {
      case 's': return c.v;
      case 'n': return c.v;
      case 'b': return c.v;
      case 'nil': return null;
      case 'sym': return { _type: 'symbol', name: c.v };
      case 'kw':  return { _type: 'keyword', name: c.v };
      case 'list': return { _type: 'list', items: (c.v || []).map(deserializeConstant) };
      case 'code': return {
        _type: 'dict',
        bytecode: { _type: 'list', items: c.v.bytecode },
        constants: { _type: 'list', items: (c.v.constants || []).map(deserializeConstant) },
        arity: c.v.arity || 0,
        'upvalue-count': c.v['upvalue-count'] || 0,
        locals: c.v.locals || 0,
      };
      case 'dict': {
        var d = { _type: 'dict' };
        for (var k in c.v) d[k] = deserializeConstant(c.v[k]);
        return d;
      }
      default: return null;
    }
  }

  /**
   * Try loading a pre-compiled bytecode module.
   * Tries .sxbc.json first, then .sxbc (SX s-expression format).
   * Returns true on success, null on failure (caller falls back to .sx source).
   */
  function loadBytecodeFile(path) {
    console.log("[sx-platform] loadBytecodeFile:", path, "(sxbc-only, no json)");
    // .sxbc.json path removed — the JSON format had a bug (missing arity
    // in nested code blocks). Use .sxbc (SX text) format only.

    // Try .sxbc (SX s-expression format, loaded via load-sxbc primitive)
    var sxbcPath = path.replace(/\.sx$/, '.sxbc');
    var sxbcUrl = _baseUrl + sxbcPath + _sxbcCacheBust;
    try {
      var xhr2 = new XMLHttpRequest();
      xhr2.open("GET", sxbcUrl, false);
      xhr2.send();
      if (xhr2.status === 200) {
        // Store text in global, parse via SX to avoid JS string escaping
        window.__sxbcText = xhr2.responseText;
        var result2 = K.eval('(load-sxbc (first (parse (host-global "__sxbcText"))))');
        delete window.__sxbcText;
        if (typeof result2 !== 'string' || result2.indexOf('Error') !== 0) {
          console.log("[sx-platform]  ok " + path + " (bytecode-sx)");
          return true;
        }
        console.warn("[sx-platform] bytecode-sx FAIL " + path + ":", result2);
      }
    } catch(e) { delete window.__sxbcText; /* fall through to source */ }

    return null;
  }

  /**
   * Load an .sx file synchronously via XHR (boot-time only).
   * Returns the number of expressions loaded, or an error string.
   */
  function loadSxFile(path) {
    var url = _baseUrl + path + _cacheBust;
    try {
      var xhr = new XMLHttpRequest();
      xhr.open("GET", url, false); // synchronous
      xhr.send();
      if (xhr.status === 200) {
        var result = K.load(xhr.responseText);
        if (typeof result === "string" && result.indexOf("Error") === 0) {
          console.error("[sx-platform] FAIL " + path + ":", result);
          return 0;
        }
        console.log("[sx-platform]  ok " + path + " (" + result + " exprs)");
        return result;
      } else {
        console.error("[sx] Failed to fetch " + path + ": HTTP " + xhr.status);
        return null;
      }
    } catch(e) {
      console.error("[sx] Failed to load " + path + ":", e);
      return null;
    }
  }

  /**
   * Load all web adapter .sx files in dependency order.
   * Tries pre-compiled bytecode first, falls back to source.
   */
  function loadWebStack() {
    var files = [
      // Spec modules
      "sx/render.sx",
      "sx/core-signals.sx",
      "sx/signals.sx",
      "sx/deps.sx",
      "sx/router.sx",
      "sx/page-helpers.sx",
      // Freeze scope (signal persistence)
      "sx/freeze.sx",
      // Bytecode compiler + VM
      "sx/bytecode.sx",
      "sx/compiler.sx",
      "sx/vm.sx",
      // Web libraries (use 8 FFI primitives)
      "sx/dom.sx",
      "sx/browser.sx",
      // Web adapters
      "sx/adapter-html.sx",
      "sx/adapter-sx.sx",
      "sx/adapter-dom.sx",
      // Client libraries (CSSX etc. — needed by page components)
      "sx/cssx.sx",
      // Boot helpers (platform functions in pure SX)
      "sx/boot-helpers.sx",
      "sx/hypersx.sx",
      // Test harness (for inline test runners)
      "sx/harness.sx",
      "sx/harness-reactive.sx",
      "sx/harness-web.sx",
      // Web framework
      "sx/engine.sx",
      "sx/orchestration.sx",
      "sx/boot.sx",
    ];

    var loaded = 0, bcCount = 0, srcCount = 0;
    var inBatch = false;
    for (var i = 0; i < files.length; i++) {
      if (!inBatch && K.beginModuleLoad) { K.beginModuleLoad(); inBatch = true; }
      var r = loadBytecodeFile(files[i]);
      if (r) { bcCount++; continue; }
      // Bytecode not available — end batch, load source
      if (inBatch && K.endModuleLoad) { K.endModuleLoad(); inBatch = false; }
      r = loadSxFile(files[i]);
      if (typeof r === "number") { loaded += r; srcCount++; }
    }
    if (inBatch && K.endModuleLoad) K.endModuleLoad();
    console.log("[sx-platform] Loaded " + files.length + " files (" + bcCount + " bytecode, " + srcCount + " source, " + loaded + " exprs)");
    return loaded;
  }

  // ================================================================
  // Compatibility shim — expose Sx global matching current JS API
  // ================================================================

  globalThis.Sx = {
    VERSION: "wasm-1.0",
    parse: function(src) { return K.parse(src); },
    eval: function(src) { return K.eval(src); },
    load: function(src) { return K.load(src); },
    renderToHtml: function(expr) { return K.renderToHtml(expr); },
    callFn: function(fn, args) { return K.callFn(fn, args); },
    engine: function() { return K.engine(); },
    // Boot entry point (called by auto-init or manually)
    init: function() {
      if (typeof K.eval === "function") {
        // Check boot-init exists
        // Step through boot manually
        console.log("[sx] init-css-tracking...");
        K.eval("(init-css-tracking)");
        console.log("[sx] process-page-scripts...");
        K.eval("(process-page-scripts)");
        console.log("[sx] routes after pages:", K.eval("(len _page-routes)"));
        console.log("[sx] process-sx-scripts...");
        K.eval("(process-sx-scripts nil)");
        console.log("[sx] sx-hydrate-elements...");
        K.eval("(sx-hydrate-elements nil)");
        console.log("[sx] sx-hydrate-islands...");
        K.eval("(sx-hydrate-islands nil)");
        console.log("[sx] process-elements...");
        K.eval("(process-elements nil)");
        // Debug islands
        console.log("[sx] ~home/stepper defined?", K.eval("(type-of ~home/stepper)"));
        console.log("[sx] ~layouts/header defined?", K.eval("(type-of ~layouts/header)"));
        // Island count (JS-side, avoids VM overhead)
        console.log("[sx] manual island query:", document.querySelectorAll("[data-sx-island]").length);
        // Try hydrating again
        console.log("[sx] retry hydrate-islands...");
        K.eval("(sx-hydrate-islands nil)");
        // Check if links are boosted
        var links = document.querySelectorAll("a[href]");
        var boosted = 0;
        for (var i = 0; i < links.length; i++) {
          if (links[i]._sxBoundboost) boosted++;
        }
        console.log("[sx] boosted links:", boosted, "/", links.length);
        // Check island state
        var islands = document.querySelectorAll("[data-sx-island]");
        console.log("[sx] islands:", islands.length);
        for (var j = 0; j < islands.length; j++) {
          console.log("[sx]   island:", islands[j].getAttribute("data-sx-island"),
            "hydrated:", !!islands[j]._sxBoundislandhydrated || !!islands[j]["_sxBound" + "island-hydrated"],
            "children:", islands[j].children.length);
        }
        // Fallback popstate handler for back/forward navigation.
        // Only fires before SX engine boots — after boot, boot.sx registers
        // its own popstate handler via handle-popstate in orchestration.sx.
        window.addEventListener("popstate", function() {
          if (document.documentElement.hasAttribute("data-sx-ready")) return;
          var url = location.pathname + location.search;
          var target = document.querySelector("#main-panel");
          if (!target) return;
          fetch(url)
            .then(function(r) { return r.text(); })
            .then(function(html) {
              if (!html) return;
              var parser = new DOMParser();
              var doc = parser.parseFromString(html, "text/html");
              var srcPanel = doc.querySelector("#main-panel");
              var srcNav = doc.querySelector("#sx-nav");
              if (srcPanel) {
                target.outerHTML = srcPanel.outerHTML;
              }
              var navTarget = document.querySelector("#sx-nav");
              if (srcNav && navTarget) {
                navTarget.outerHTML = srcNav.outerHTML;
              }
            })
            .catch(function(e) { console.warn("[sx] popstate fetch error:", e); });
        });
        // Event delegation for sx-get links — fallback when bind-event's
        // per-element listener didn't attach. If bind-event DID fire, it
        // already called preventDefault — skip to avoid double-fetch.
        document.addEventListener("click", function(e) {
          var el = e.target.closest("a[sx-get]");
          if (!el) return;
          if (e.defaultPrevented) return;
          if (e.metaKey || e.ctrlKey || e.shiftKey || e.altKey) return;
          e.preventDefault();
          var url = el.getAttribute("href") || el.getAttribute("sx-get");
          // Don't push URL here — execute-request's handle-history does it.
          // Double-push causes popstate handler to clobber the SX swap.
          // Store the element reference for SX to pick up
          window.__sxClickEl = el;
          try {
            K.eval('(execute-request (host-global "__sxClickEl") nil nil)');
          } catch(ex) {
            console.warn("[sx] click delegation error:", ex);
            location.href = el.href;
          }
          delete window.__sxClickEl;
        });

        // Signal boot complete
        document.documentElement.setAttribute("data-sx-ready", "true");
        document.dispatchEvent(new CustomEvent("sx:boot-done"));
        console.log("[sx] boot done");
      }
    }
  };

  // ================================================================
  // Auto-init: load web stack and boot on DOMContentLoaded
  // ================================================================

  if (typeof document !== "undefined") {
    var _doInit = function() {
      loadWebStack();
      Sx.init();
      // Enable JIT after all boot code has run
      setTimeout(function() { K.eval('(enable-jit!)'); }, 0);
    };

    if (document.readyState === "loading") {
      document.addEventListener("DOMContentLoaded", _doInit);
    } else {
      _doInit();
    }
  }

  } // end boot

  // SxKernel is available synchronously (js_of_ocaml) or after async
  // WASM init. Poll briefly to handle both cases.
  var K = globalThis.SxKernel;
  if (K) { boot(K); return; }
  var tries = 0;
  var poll = setInterval(function() {
    K = globalThis.SxKernel;
    if (K) { clearInterval(poll); boot(K); }
    else if (++tries > 100) { clearInterval(poll); console.error("[sx-platform] SxKernel not found after 5s"); }
  }, 50);
})();