/**
 * 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 from current script
  var _cacheBust = "";
  (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);
          break;
        }
      }
    }
  })();

  /**
   * Deserialize type-tagged JSON constant back to JS value for loadModule.
   * (Legacy — used for .sxbc.json fallback)
   */
  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 (s-expression) first, falls back to .sxbc.json (legacy).
   * Returns true on success, null on failure (caller falls back to .sx source).
   */
  function loadBytecodeFile(path) {
    // Try .sxbc (s-expression format) first
    var sxbcPath = path.replace(/\.sx$/, '.sxbc');
    var url = _baseUrl + sxbcPath + _cacheBust;
    try {
      var xhr = new XMLHttpRequest();
      xhr.open("GET", url, false);
      xhr.send();
      if (xhr.status === 200 && xhr.responseText.indexOf("(sxbc") === 0) {
        // Parse with the SX kernel — returns the (sxbc ...) form
        var parsed = K.eval('(first (sx-parse ' + JSON.stringify(xhr.responseText) + '))');
        // (sxbc version hash (code ...)) — third element is the module
        var module = K.eval('(nth (sx-parse ' + JSON.stringify(xhr.responseText) + ') 0)');
        // Use evalSxbc which understands the sxbc format
        var result = K.eval('(load-sxbc (first (sx-parse ' + JSON.stringify(xhr.responseText) + ')))');
        if (typeof result === 'string' && result.indexOf('Error') === 0) {
          console.warn("[sx-platform] sxbc FAIL " + path + ":", result);
        } else {
          return true;
        }
      }
    } catch(e) {
      // Fall through to JSON
    }

    // Fallback: .sxbc.json (legacy format)
    var bcPath = path.replace(/\.sx$/, '.sxbc.json');
    url = _baseUrl + bcPath + _cacheBust;
    try {
      var xhr2 = new XMLHttpRequest();
      xhr2.open("GET", url, false);
      xhr2.send();
      if (xhr2.status !== 200) return null;

      var json = JSON.parse(xhr2.responseText);
      if (!json.module || json.magic !== 'SXBC') return null;

      var module2 = {
        _type: 'dict',
        bytecode: { _type: 'list', items: json.module.bytecode },
        constants: { _type: 'list', items: json.module.constants.map(deserializeConstant) },
      };

      var result2 = K.loadModule(module2);
      if (typeof result2 === 'string' && result2.indexOf('Error') === 0) {
        console.warn("[sx-platform] bytecode FAIL " + path + ":", result2);
        return null;
      }
      return true;
    } catch(e) {
      console.error("[sx-platform] bytecode EXCEPTION " + path + ":", e);
      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",
      // 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 t0 = performance.now();
    var forceSrc = (typeof window !== "undefined" && window.location.search.indexOf("nosxbc") !== -1);
    if (!forceSrc && K.beginModuleLoad) K.beginModuleLoad();
    for (var i = 0; i < files.length; i++) {
      if (!forceSrc) {
        var r = loadBytecodeFile(files[i]);
        if (r) { bcCount++; continue; }
      }
      // Bytecode not available — end batch, load source, restart batch
      if (!forceSrc && K.endModuleLoad) K.endModuleLoad();
      r = loadSxFile(files[i]);
      if (typeof r === "number") { loaded += r; srcCount++; }
      if (!forceSrc && K.beginModuleLoad) K.beginModuleLoad();
    }
    if (!forceSrc && K.endModuleLoad) K.endModuleLoad();
    var elapsed = Math.round(performance.now() - t0);
    console.log("[sx-platform] Loaded " + files.length + " files (" + bcCount + " bytecode, " + srcCount + " source, " + loaded + " exprs) in " + elapsed + "ms");
    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") return;
      var steps = [
        '(log-info (str "sx-browser " SX_VERSION))',
        '(init-css-tracking)',
        '(process-page-scripts)',
        '(process-sx-scripts nil)',
        '(sx-hydrate-elements nil)',
        '(sx-hydrate-islands nil)',
        '(run-post-render-hooks)',
        '(process-elements nil)',
        '(dom-listen (dom-window) "popstate" (fn (e) (handle-popstate 0)))'
      ];
      var failures = [];
      for (var i = 0; i < steps.length; i++) {
        try {
          var r = K.eval(steps[i]);
          if (typeof r === "string" && r.indexOf("Error") === 0) {
            console.error("[sx] boot step " + i + " FAILED: " + steps[i].substring(0, 60), r);
            failures.push({ step: i, expr: steps[i], error: r });
          }
        } catch(e) {
          console.error("[sx] boot step " + i + " THREW: " + steps[i].substring(0, 60), e);
          failures.push({ step: i, expr: steps[i], error: String(e) });
        }
      }
      if (failures.length > 0) {
        console.error("[sx] BOOT FAILED: " + failures.length + " step(s) errored:", failures.map(function(f) { return "step " + f.step + ": " + f.error; }).join("; "));
      }
    }
  };

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

  if (typeof document !== "undefined") {
    var _doInit = function() {
      loadWebStack();
      Sx.init();
      // JIT disabled for debugging
      // 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);
})();