// 沙盒驗收流程：五個步驟依序執行
// Requirements: 2.1, 2.2, 2.3

import { FORBIDDEN_SYSCALLS } from '../types';
import type { ComponentContract, SandboxResult, SandboxStep } from '../types';

// ── 步驟 (a)：體積檢查 ────────────────────────────────────────────────────────

function checkSize(wasmBytes: Uint8Array, contract: ComponentContract): string | null {
  const maxSizeKb = contract.constraints.max_size_kb;
  const actualKb = wasmBytes.byteLength / 1024;
  if (actualKb > maxSizeKb) {
    return `體積 ${actualKb.toFixed(1)}KB 超過上限 ${maxSizeKb}KB`;
  }
  return null;
}

// ── 步驟 (b)：冷啟動時間（Phase 0 mock 0ms）────────────────────────────────────

function checkColdStart(_wasmBytes: Uint8Array, _contract: ComponentContract): string | null {
  // Phase 0：mock 通過，記錄 0ms
  // Phase 2 再實作真實測量
  return null;
}

// ── 步驟 (c)：syscall 掃描 ────────────────────────────────────────────────────

function scanSyscalls(wasmBytes: Uint8Array): string | null {
  // 將 .wasm binary 轉為文字，搜尋禁止的 import 字串
  // WASM binary 中 import section 的函數名稱以 UTF-8 字串形式存在
  const text = new TextDecoder('utf-8', { fatal: false }).decode(wasmBytes);

  for (const syscall of FORBIDDEN_SYSCALLS) {
    if (text.includes(syscall)) {
      return `發現禁止的 syscall：${syscall}`;
    }
  }
  return null;
}

// ── 步驟 (d)：Gherkin 測試（Phase 0 mock 通過）────────────────────────────────

function runGherkinTests(_wasmBytes: Uint8Array, _contract: ComponentContract): string | null {
  // Phase 0：mock 通過
  // Phase 1 再實作真實 Gherkin 執行
  return null;
}

// ── 步驟 (e)：runtime 相容測試（Phase 0 mock 通過）────────────────────────────

function checkRuntimeCompat(_wasmBytes: Uint8Array, _contract: ComponentContract): string | null {
  // Phase 0：mock 通過
  // Phase 2 再實作真實多 runtime 測試
  return null;
}

// ── 主流程 ────────────────────────────────────────────────────────────────────

interface StepDef {
  name: SandboxStep;
  run: (wasmBytes: Uint8Array, contract: ComponentContract) => string | null;
  guideAnchor: string;
}

const STEPS: StepDef[] = [
  { name: 'size_check',     run: checkSize,           guideAnchor: '#common-errors' },
  { name: 'cold_start',     run: checkColdStart,      guideAnchor: '#common-errors' },
  { name: 'syscall_scan',   run: scanSyscalls,        guideAnchor: '#syscall-constraints' },
  { name: 'gherkin_tests',  run: runGherkinTests,     guideAnchor: '#local-testing' },
  { name: 'runtime_compat', run: checkRuntimeCompat,  guideAnchor: '#contract-example' },
];

export function runSandboxAcceptance(
  wasmBytes: Uint8Array,
  contract: ComponentContract,
): SandboxResult {
  for (const step of STEPS) {
    const error = step.run(wasmBytes, contract);
    if (error !== null) {
      return {
        success: false,
        failed_step: step.name,
        reason: error,
        guide_anchor: step.guideAnchor,
        component_id: contract.canonical_id,
        version: contract.version,
      };
    }
  }

  return {
    success: true,
    component_id: contract.canonical_id,
    version: contract.version,
  };
}