/**
 * BOB IDE WASM ENGINE
 * WebAssembly + WebSocket bindings for AssemblyScript execution
 * Real-time kernel access for quantum operations
 */

import { EventEmitter } from 'events';

interface WasmModule {
  memory: WebAssembly.Memory;
  exports: Record<string, any>;
}

interface WasmContext {
  module: WasmModule;
  instance: WebAssembly.Instance;
  memory: Uint8Array;
  heap: Map<number, any>;
}

export class WasmEngine extends EventEmitter {
  private contexts: Map<string, WasmContext> = new Map();
  private wsConnections: Map<string, any> = new Map();

  /**
   * Load AssemblyScript WASM module
   */
  async loadModule(name: string, wasmBuffer: Buffer): Promise<string> {
    try {
      const wasmModule = await WebAssembly.instantiate(wasmBuffer, {
        env: {
          abort: (msg: number, file: number, line: number, col: number) => {
            console.error(`ABORT: msg=${msg} file=${file} line=${line} col=${col}`);
          },
          trace: (msg: number) => {
            console.log(`TRACE: ${msg}`);
          },
        },
      });

      const module: WasmModule = {
        memory: (wasmModule.instance.exports.memory as WebAssembly.Memory),
        exports: wasmModule.instance.exports,
      };

      const contextId = `wasm-${Date.now()}-${Math.random().toString(36).slice(2, 9)}`;

      this.contexts.set(contextId, {
        module,
        instance: wasmModule.instance,
        memory: new Uint8Array((wasmModule.instance.exports.memory as WebAssembly.Memory).buffer),
        heap: new Map(),
      });

      this.emit('module-loaded', { contextId, name });
      return contextId;
    } catch (e) {
      this.emit('error', { error: e, module: name });
      throw e;
    }
  }

  /**
   * Execute WASM function
   */
  async call(
    contextId: string,
    functionName: string,
    args: any[]
  ): Promise<any> {
    const ctx = this.contexts.get(contextId);
    if (!ctx) throw new Error(`Context ${contextId} not found`);

    const fn = ctx.module.exports[functionName];
    if (!fn) throw new Error(`Function ${functionName} not found`);

    try {
      const result = fn(...args);
      this.emit('call', { contextId, functionName, args, result });
      return result;
    } catch (e) {
      this.emit('error', { contextId, functionName, error: e });
      throw e;
    }
  }

  /**
   * Read WASM linear memory
   */
  readMemory(contextId: string, ptr: number, len: number): Buffer {
    const ctx = this.contexts.get(contextId);
    if (!ctx) throw new Error(`Context ${contextId} not found`);
    return Buffer.from(ctx.memory.slice(ptr, ptr + len));
  }

  /**
   * Write WASM linear memory
   */
  writeMemory(contextId: string, ptr: number, data: Buffer): void {
    const ctx = this.contexts.get(contextId);
    if (!ctx) throw new Error(`Context ${contextId} not found`);
    ctx.memory.set(data, ptr);
  }

  /**
   * Allocate WASM memory
   */
  async allocate(contextId: string, size: number): Promise<number> {
    const ctx = this.contexts.get(contextId);
    if (!ctx) throw new Error(`Context ${contextId} not found`);

    const alloc = ctx.module.exports.__alloc as (size: number, id: number) => number;
    if (!alloc) throw new Error('Allocator not found');

    return alloc(size, 0);
  }

  /**
   * Deallocate WASM memory
   */
  async deallocate(contextId: string, ptr: number): Promise<void> {
    const ctx = this.contexts.get(contextId);
    if (!ctx) throw new Error(`Context ${contextId} not found`);

    const free = ctx.module.exports.__release as (ptr: number) => void;
    if (!free) return;

    free(ptr);
  }

  /**
   * WebSocket handler for real-time WASM execution
   */
  wsHandler(ws: any, contextId: string) {
    this.wsConnections.set(contextId, ws);

    ws.on('message', async (msg: Buffer) => {
      try {
        const data = JSON.parse(msg.toString());

        if (data.type === 'call') {
          const result = await this.call(data.contextId, data.fn, data.args);
          ws.send(JSON.stringify({ type: 'result', id: data.id, result }));
        } else if (data.type === 'read') {
          const buf = this.readMemory(data.contextId, data.ptr, data.len);
          ws.send(JSON.stringify({ type: 'data', id: data.id, data: buf.toString('base64') }));
        } else if (data.type === 'write') {
          const buf = Buffer.from(data.data, 'base64');
          this.writeMemory(data.contextId, data.ptr, buf);
          ws.send(JSON.stringify({ type: 'ack', id: data.id }));
        } else if (data.type === 'alloc') {
          const ptr = await this.allocate(data.contextId, data.size);
          ws.send(JSON.stringify({ type: 'ptr', id: data.id, ptr }));
        } else if (data.type === 'free') {
          await this.deallocate(data.contextId, data.ptr);
          ws.send(JSON.stringify({ type: 'ack', id: data.id }));
        }
      } catch (e: any) {
        ws.send(JSON.stringify({ type: 'error', error: e.message }));
      }
    });

    ws.on('close', () => {
      this.wsConnections.delete(contextId);
    });
  }

  /**
   * Execute AssemblyScript stream processor
   */
  async streamProcess(
    contextId: string,
    inputFn: string,
    transformFn: string,
    chunks: Buffer[]
  ): Promise<Buffer[]> {
    const ctx = this.contexts.get(contextId);
    if (!ctx) throw new Error(`Context ${contextId} not found`);

    const results: Buffer[] = [];

    for (const chunk of chunks) {
      // Allocate memory for input
      const inputPtr = await this.allocate(contextId, chunk.length);
      this.writeMemory(contextId, inputPtr, chunk);

      try {
        // Call transform function
        const outputPtr = await this.call(contextId, transformFn, [inputPtr, chunk.length]);

        // Read output (assuming it returns a pointer)
        const output = this.readMemory(contextId, outputPtr, chunk.length * 2); // Assume max 2x
        results.push(output);
      } finally {
        // Free input memory
        await this.deallocate(contextId, inputPtr);
      }
    }

    return results;
  }

  /**
   * Get WASM execution stats
   */
  getStats(contextId: string): any {
    const ctx = this.contexts.get(contextId);
    if (!ctx) return null;

    return {
      contextId,
      memoryPages: (ctx.module.memory.buffer.byteLength / 65536),
      allocations: ctx.heap.size,
    };
  }

  /**
   * Cleanup context
   */
  cleanup(contextId: string): void {
    this.contexts.delete(contextId);
    this.wsConnections.delete(contextId);
  }
}

// =====================================================================
// ASSEMBLYSCRIPT BINDINGS
// =====================================================================

/**
 * AssemblyScript skeleton module
 * Compile with: asc wasm-module.ts -t wasm-module.wasm
 *
 * ```typescript
 * // wasm-module.ts
 *
 * export function hash_blake3(ptr: usize, len: usize): usize {
 *   // Implement Blake3 hash in WASM
 *   // Return pointer to 32-byte hash
 *   return 0;
 * }
 *
 * export function sign_ed25519(ptr: usize, len: usize): usize {
 *   // Implement Ed25519 signing in WASM
 *   // Return pointer to 64-byte signature
 *   return 0;
 * }
 *
 * export function quantum_evolve(ptr: usize, steps: i32): void {
 *   // Quantum lattice evolution
 *   // Modify state in-place
 * }
 *
 * export function compress_artifact(src: usize, srcLen: usize, dst: usize): i32 {
 *   // Compress artifact, return compressed size
 *   return 0;
 * }
 * ```
 */

export const ASSEMBLYSCRIPT_SKELETON = `
import { memory } from "./env";

// Blake3 hash (simplified)
export function hash_blake3(ptr: usize, len: usize): usize {
  const hash = memory.data_mut(32);
  let h: u32 = 0x811c9dc5;
  for (let i: usize = 0; i < len; i++) {
    const byte = load<u8>(ptr + i);
    h ^= byte;
    h = ((h * 0x01000193) >>> 0) as u32;
  }
  store<u32>(hash, h);
  return hash as usize;
}

// Ed25519 sign (simplified)
export function sign_ed25519(ptr: usize, len: usize): usize {
  const sig = memory.data_mut(64);
  // Simplified: just write 64 bytes
  for (let i: usize = 0; i < 64; i++) {
    store<u8>(sig + i, i as u8);
  }
  return sig as usize;
}

// Quantum lattice evolution
export function quantum_evolve(ptr: usize, steps: i32): void {
  for (let step = 0; step < steps; step++) {
    // Update lattice state
  }
}

// Compress artifact
export function compress_artifact(src: usize, srcLen: usize, dst: usize): i32 {
  let compressed = 0;
  for (let i: usize = 0; i < srcLen; i++) {
    const byte = load<u8>(src + i);
    if (i % 4 === 0) {
      store<u8>(dst + compressed, byte);
      compressed++;
    }
  }
  return compressed as i32;
}

// Decompress artifact
export function decompress_artifact(src: usize, srcLen: usize, dst: usize): i32 {
  let decompressed = 0;
  for (let i: usize = 0; i < srcLen; i++) {
    const byte = load<u8>(src + i);
    store<u8>(dst + decompressed, byte);
    decompressed++;
    if (decompressed % 4 === 0) {
      store<u8>(dst + decompressed, 0);
      decompressed++;
    }
  }
  return decompressed as i32;
}
`;