import { describe, it, expect } from 'vitest';
import { parseSpeckContent } from '../src/parser.js';
import { generateWASM } from '../src/generators/wasm.js';
import { createHostImports, bindMemory, readScalarState } from '../src/runtime/wasm-host.js';
import fs from 'fs';
import path from 'path';
import os from 'os';

// Dynamic import wabt since it's a CommonJS module
async function loadWabt() {
  const wabt = await import('wabt');
  return wabt.default();
}

describe('SpeckDL WASM E2E', () => {
  it('should compile Counter speck to WAT, assemble to WASM, and run in Node.js', async () => {
    // A minimal scalar-only speck that we can fully compile and run
    // NOTE: Parser requires braces on the SAME line as block keywords
    const speckSource = `speck Counter {
  author: "Speckl Compiler v0.3"
  source: document ref "WASM-E2E"
  review: automated

  state: {
    count: Nat := 0
    maxCount: Nat := 10
  }

  init: {
    count := 0
    maxCount := 10
  }

  action Increment() {
    require count < maxCount
    count := count + 1
  }

  action Decrement() {
    require count > 0
    count := count - 1
  }

  action Reset() {
    count := 0
  }

  action GetCount() {
    return count
  }
}`;

    // 1. Parse
    const ast = parseSpeckContent(speckSource);
    expect(ast.specks).toHaveLength(1);
    expect(ast.specks[0].name).toBe('Counter');

    // 2. Generate WAT to temp dir
    const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'speckl-wasm-e2e-'));
    generateWASM(ast, tmpDir);

    const watPath = path.join(tmpDir, 'Counter.wat');
    expect(fs.existsSync(watPath)).toBe(true);

    const watContent = fs.readFileSync(watPath, 'utf-8');
    expect(watContent).toContain('(module');
    expect(watContent).toContain('(export "init")');
    expect(watContent).toContain('(export "Increment")');
    expect(watContent).toContain('(export "Decrement")');
    expect(watContent).toContain('(export "Reset")');
    expect(watContent).toContain('(export "GetCount")');
    expect(watContent).toContain('(export "getState")');
    expect(watContent).toContain('(export "memory")');

    // 3. Assemble WAT → WASM using wabt
    const wabtModule = await loadWabt();
    const wasmModule = wabtModule.parseWat('Counter.wat', watContent);
    wasmModule.resolveNames();
    wasmModule.validate({ features: {} });
    const binaryOutput = wasmModule.toBinary({ log: false, write_debug_names: false });
    const wasmBytes = binaryOutput.buffer;

    expect(wasmBytes.length).toBeGreaterThan(0);
    expect(wasmBytes.length).toBeGreaterThan(50); // Not just empty header

    // 4. Instantiate with host runtime
    const hostState = {
      maps: new Map(),
      sets: new Map(),
      nextHandle: 1,
      memory: null as WebAssembly.Memory | null,
    };
    const imports = { speckl: createHostImports(hostState) };

    const wasm = await WebAssembly.instantiate(wasmBytes, imports);
    const memory = wasm.instance.exports.memory as WebAssembly.Memory;
    bindMemory(hostState, memory);

    // 5. Verify exports
    expect(typeof wasm.instance.exports.init).toBe('function');
    expect(typeof wasm.instance.exports.Increment).toBe('function');
    expect(typeof wasm.instance.exports.Decrement).toBe('function');
    expect(typeof wasm.instance.exports.Reset).toBe('function');
    expect(typeof wasm.instance.exports.GetCount).toBe('function');
    expect(typeof wasm.instance.exports.getState).toBe('function');
    expect(memory).toBeInstanceOf(WebAssembly.Memory);

    // 6. Run init
    (wasm.instance.exports.init as Function)();

    // 7. Verify initial state via getState
    const stateResult = (wasm.instance.exports.getState as Function)();
    // getState returns i32 i32 (ptr, len)
    expect(stateResult).toBeDefined();

    // Read memory directly to verify state
    const scalarState = readScalarState(memory, ['count', 'maxCount']);
    expect(scalarState.count).toBe(0);
    expect(scalarState.maxCount).toBe(10);

    // 8. Run Increment 3 times, calling getState after each to sync memory
    for (let i = 0; i < 3; i++) {
      const ret = (wasm.instance.exports.Increment as Function)();
      expect(ret).toBe(1); // Success
      (wasm.instance.exports.getState as Function)(); // Sync globals to memory
    }

    const afterIncrement = readScalarState(memory, ['count', 'maxCount']);
    expect(afterIncrement.count).toBe(3);
    expect(afterIncrement.maxCount).toBe(10);

    // 9. Run Decrement once
    const decRet = (wasm.instance.exports.Decrement as Function)();
    expect(decRet).toBe(1); // Success
    (wasm.instance.exports.getState as Function)();

    const afterDecrement = readScalarState(memory, ['count', 'maxCount']);
    expect(afterDecrement.count).toBe(2);

    // 10. Run GetCount — should return current count (global, not memory)
    const getRet = (wasm.instance.exports.GetCount as Function)();
    expect(getRet).toBe(2);

    // 11. Run Reset
    const resetRet = (wasm.instance.exports.Reset as Function)();
    expect(resetRet).toBe(1); // Success
    (wasm.instance.exports.getState as Function)();

    const afterReset = readScalarState(memory, ['count', 'maxCount']);
    expect(afterReset.count).toBe(0);

    // 12. Guard test: Decrement at 0 should fail
    const guardFail = (wasm.instance.exports.Decrement as Function)();
    expect(guardFail).toBe(0); // Guard failed → return 0

    // 13. Guard test: Increment at maxCount should fail
    // First increment to max
    for (let i = 0; i < 10; i++) {
      (wasm.instance.exports.Increment as Function)();
    }
    (wasm.instance.exports.getState as Function)();
    const atMax = readScalarState(memory, ['count', 'maxCount']);
    expect(atMax.count).toBe(10);

    const maxGuardFail = (wasm.instance.exports.Increment as Function)();
    expect(maxGuardFail).toBe(0); // Guard failed → return 0

    // Cleanup
    fs.rmSync(tmpDir, { recursive: true, force: true });
  }, 30000); // 30s timeout for wabt compilation

  it('should compile TigerBeetle speck to valid WAT that wabt accepts', async () => {
    // Load the full TigerBeetle speck from file
    const speckPath = path.join(__dirname, 'tigerbeetle.speck');
    const speckSource = fs.readFileSync(speckPath, 'utf-8');

    const ast = parseSpeckContent(speckSource);
    expect(ast.specks).toHaveLength(1);
    expect(ast.specks[0].name).toBe('TigerBeetle');

    const tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), 'speckl-wasm-e2e-tb-'));
    generateWASM(ast, tmpDir);

    const watPath = path.join(tmpDir, 'TigerBeetle.wat');
    expect(fs.existsSync(watPath)).toBe(true);

    const watContent = fs.readFileSync(watPath, 'utf-8');

    // Validate with wabt
    const wabtModule = await loadWabt();
    const wasmModule = wabtModule.parseWat('TigerBeetle.wat', watContent);

    // These should not throw
    wasmModule.resolveNames();
    wasmModule.validate({ features: {} });
    const binaryOutput = wasmModule.toBinary({ log: false, write_debug_names: false });

    expect(binaryOutput.buffer.length).toBeGreaterThan(100);

    // Cleanup
    fs.rmSync(tmpDir, { recursive: true, force: true });
  }, 30000);
});