import { mkdir, readFile, readdir, writeFile } from 'node:fs/promises';
import path from 'node:path';
import { fileURLToPath } from 'node:url';

import {
  BACKEND_CAPABILITY_MANIFEST,
  type BackendCapabilityManifest,
  type BackendDomainModule,
  type BackendRouteCapability,
  type BackendRouteSurface,
} from '../src/manifest/backendCapabilityManifest.js';

type GeneratedSummary = {
  surfaceCount: number;
  routeCount: number;
  moduleCount: number;
  publicRouteCount: number;
  jwtRouteCount: number;
  envSwitchRouteCount: number;
  streamRouteCount: number;
};

type GeneratedArtifact = {
  generatedAt: string;
  manifestVersion: string;
  generatedCommand: string;
  outputTargets: BackendCapabilityManifest['outputTargets'];
  summary: GeneratedSummary;
  surfaces: Array<
    BackendRouteSurface & {
      routeCount: number;
      routeIds: string[];
    }
  >;
  modules: Array<
    BackendDomainModule & {
      routeCount: number;
      routeIds: string[];
    }
  >;
  routes: BackendRouteCapability[];
  maintenanceRules: string[];
};

const currentFilePath = fileURLToPath(import.meta.url);
const scriptDirectory = path.dirname(currentFilePath);
const repoRoot = path.resolve(scriptDirectory, '..', '..');

/**
 * 统一把 repo 相对路径转成绝对路径，避免不同工作目录下解析不一致。
 */
function resolveRepoPath(relativePath: string) {
  return path.resolve(repoRoot, relativePath);
}

function sortById<T extends { id: string }>(items: T[]) {
  return [...items].sort((left, right) => left.id.localeCompare(right.id, 'zh-Hans-CN'));
}

function sortRoutes(routes: BackendRouteCapability[]) {
  return [...routes].sort((left, right) => {
    if (left.path === right.path) {
      return left.method.localeCompare(right.method, 'en-US');
    }
    return left.path.localeCompare(right.path, 'en-US');
  });
}

/**
 * 用最小约束校验 manifest 的唯一性与引用完整性，确保生成结果可维护。
 */
function assertUniqueIds(items: Array<{ id: string }>, label: string) {
  const seen = new Set<string>();
  const duplicates: string[] = [];

  items.forEach((item) => {
    if (seen.has(item.id)) {
      duplicates.push(item.id);
      return;
    }
    seen.add(item.id);
  });

  if (duplicates.length > 0) {
    throw new Error(`${label} 存在重复 id：${duplicates.join('、')}`);
  }
}

async function assertSourceFileContains(params: {
  sourceFile: string;
  sourceHint: string;
  routeId: string;
}) {
  const absolutePath = resolveRepoPath(params.sourceFile);
  const content = await readFile(absolutePath, 'utf8');
  if (!content.includes(params.sourceHint)) {
    throw new Error(
      `路由 ${params.routeId} 的 sourceHint 未命中源码：${params.sourceFile} -> ${params.sourceHint}`,
    );
  }
}

async function validateModuleCoverage(modules: BackendDomainModule[]) {
  const modulesRoot = resolveRepoPath('server-node/src/modules');
  const directoryEntries = await readdir(modulesRoot, { withFileTypes: true });
  const actualDirectories = directoryEntries
    .filter((entry) => entry.isDirectory())
    .map((entry) => `server-node/src/modules/${entry.name}`)
    .sort((left, right) => left.localeCompare(right, 'en-US'));
  const manifestDirectories = modules
    .map((moduleItem) => moduleItem.directory)
    .sort((left, right) => left.localeCompare(right, 'en-US'));

  const missingInManifest = actualDirectories.filter(
    (directory) => !manifestDirectories.includes(directory),
  );
  const staleInManifest = manifestDirectories.filter(
    (directory) => !actualDirectories.includes(directory),
  );

  if (missingInManifest.length > 0) {
    throw new Error(
      `以下模块目录尚未进入能力 manifest：${missingInManifest.join('、')}`,
    );
  }

  if (staleInManifest.length > 0) {
    throw new Error(
      `manifest 中存在已失效的模块目录：${staleInManifest.join('、')}`,
    );
  }
}

async function validateManifest(manifest: BackendCapabilityManifest) {
  assertUniqueIds(manifest.surfaces, '挂载面');
  assertUniqueIds(manifest.modules, '内部模块');
  assertUniqueIds(manifest.routes, '路由');

  const surfaceIds = new Set(manifest.surfaces.map((surface) => surface.id));
  const moduleIds = new Set(manifest.modules.map((moduleItem) => moduleItem.id));

  for (const surface of manifest.surfaces) {
    for (const relatedModuleId of surface.relatedModuleIds) {
      if (!moduleIds.has(relatedModuleId)) {
        throw new Error(
          `挂载面 ${surface.id} 引用了未定义的模块：${relatedModuleId}`,
        );
      }
    }

    for (const mount of surface.mounts) {
      const absoluteEntryPath = resolveRepoPath(mount.entryFile);
      const content = await readFile(absoluteEntryPath, 'utf8');
      if (!content.includes(mount.routeFactory)) {
        throw new Error(
          `挂载面 ${surface.id} 的入口文件缺少工厂引用：${mount.entryFile} -> ${mount.routeFactory}`,
        );
      }
    }
  }

  for (const moduleItem of manifest.modules) {
    for (const surfaceId of moduleItem.exposedBySurfaceIds) {
      if (!surfaceIds.has(surfaceId)) {
        throw new Error(
          `模块 ${moduleItem.id} 引用了未定义的挂载面：${surfaceId}`,
        );
      }
    }

    const absoluteDirectory = resolveRepoPath(moduleItem.directory);
    const statsEntries = await readdir(absoluteDirectory);
    if (statsEntries.length === 0) {
      throw new Error(`模块目录为空，无法作为能力边界：${moduleItem.directory}`);
    }
  }

  for (const route of manifest.routes) {
    if (!surfaceIds.has(route.surfaceId)) {
      throw new Error(`路由 ${route.id} 引用了未定义的挂载面：${route.surfaceId}`);
    }

    for (const moduleId of route.domainModuleIds) {
      if (!moduleIds.has(moduleId)) {
        throw new Error(`路由 ${route.id} 引用了未定义的模块：${moduleId}`);
      }
    }

    await assertSourceFileContains({
      sourceFile: route.sourceFile,
      sourceHint: route.sourceHint,
      routeId: route.id,
    });
  }

  await validateModuleCoverage(manifest.modules);
}

function buildSummary(routes: BackendRouteCapability[]): GeneratedSummary {
  return {
    surfaceCount: BACKEND_CAPABILITY_MANIFEST.surfaces.length,
    routeCount: routes.length,
    moduleCount: BACKEND_CAPABILITY_MANIFEST.modules.length,
    publicRouteCount: routes.filter((route) => route.access === '公开').length,
    jwtRouteCount: routes.filter((route) => route.access === 'JWT').length,
    envSwitchRouteCount: routes.filter((route) => route.access.startsWith('开关:')).length,
    streamRouteCount: routes.filter((route) => route.responseMode === 'stream').length,
  };
}

function buildArtifact(manifest: BackendCapabilityManifest): GeneratedArtifact {
  const routes = sortRoutes(manifest.routes);
  const summary = buildSummary(routes);

  const surfaces = sortById(manifest.surfaces).map((surface) => {
    const surfaceRoutes = routes.filter((route) => route.surfaceId === surface.id);
    return {
      ...surface,
      routeCount: surfaceRoutes.length,
      routeIds: surfaceRoutes.map((route) => route.id),
    };
  });

  const modules = sortById(manifest.modules).map((moduleItem) => {
    const moduleRoutes = routes.filter((route) =>
      route.domainModuleIds.includes(moduleItem.id),
    );
    return {
      ...moduleItem,
      routeCount: moduleRoutes.length,
      routeIds: moduleRoutes.map((route) => route.id),
    };
  });

  return {
    generatedAt: new Date().toISOString(),
    manifestVersion: manifest.version,
    generatedCommand: manifest.generatedCommand,
    outputTargets: manifest.outputTargets,
    summary,
    surfaces,
    modules,
    routes,
    maintenanceRules: manifest.maintenanceRules,
  };
}

function renderMarkdown(artifact: GeneratedArtifact) {
  const lines: string[] = [];
  lines.push('# Node 后端模块与接口索引');
  lines.push('');
  lines.push('> 该文档由 `server-node/src/manifest/backendCapabilityManifest.ts` 自动生成。');
  lines.push(`> 生成命令：\`${artifact.generatedCommand}\``);
  lines.push(`> 生成时间：\`${artifact.generatedAt}\``);
  lines.push('');
  lines.push('## 总览');
  lines.push('');
  lines.push(`- 对外挂载面：${artifact.summary.surfaceCount} 个`);
  lines.push(`- 已登记路由：${artifact.summary.routeCount} 条`);
  lines.push(`- 内部模块目录：${artifact.summary.moduleCount} 个`);
  lines.push(`- 公开接口：${artifact.summary.publicRouteCount} 条`);
  lines.push(`- JWT 接口：${artifact.summary.jwtRouteCount} 条`);
  lines.push(`- 受环境开关控制的接口：${artifact.summary.envSwitchRouteCount} 条`);
  lines.push(`- 流式接口：${artifact.summary.streamRouteCount} 条`);
  lines.push('');
  lines.push('## 产物');
  lines.push('');
  lines.push(`- JSON 清单：\`${artifact.outputTargets.json}\``);
  lines.push(`- Markdown 索引：\`${artifact.outputTargets.markdown}\``);
  lines.push(`- Manifest 源：\`server-node/src/manifest/backendCapabilityManifest.ts\``);
  lines.push('');
  lines.push('## 对外挂载面');
  lines.push('');

  artifact.surfaces.forEach((surface) => {
    lines.push(`### ${surface.title}`);
    lines.push('');
    lines.push(`- 标识：\`${surface.id}\``);
    lines.push(`- 路由数：${surface.routeCount}`);
    lines.push(`- 入口：${surface.mounts.map((mount) => `\`${mount.entryFile} -> ${mount.mountPath} -> ${mount.routeFactory}\``).join('；')}`);
    lines.push(`- 关联模块：${surface.relatedModuleIds.length > 0 ? surface.relatedModuleIds.map((moduleId) => `\`${moduleId}\``).join('、') : '无'}`);
    lines.push('- 责任：');
    surface.responsibilities.forEach((item) => {
      lines.push(`  - ${item}`);
    });
    lines.push('- 主要服务边界：');
    surface.primaryServiceBoundaries.forEach((item) => {
      lines.push(`  - ${item}`);
    });
    lines.push('');
  });

  lines.push('## 接口索引');
  lines.push('');
  lines.push('| 方法 | 路径 | 访问 | 响应 | 挂载面 | 内部模块 | 说明 |');
  lines.push('| --- | --- | --- | --- | --- | --- | --- |');
  artifact.routes.forEach((route) => {
    const moduleLabel =
      route.domainModuleIds.length > 0
        ? route.domainModuleIds.map((moduleId) => `\`${moduleId}\``).join('、')
        : '无';
    lines.push(
      `| ${route.method} | \`${route.path}\` | ${route.access} | ${route.responseMode} | \`${route.surfaceId}\` | ${moduleLabel} | ${route.summary} |`,
    );
  });
  lines.push('');

  lines.push('## 内部模块边界');
  lines.push('');
  artifact.modules.forEach((moduleItem) => {
    lines.push(`### ${moduleItem.title}`);
    lines.push('');
    lines.push(`- 标识：\`${moduleItem.id}\``);
    lines.push(`- 目录：\`${moduleItem.directory}\``);
    lines.push(`- 对外可见面：${moduleItem.exposedBySurfaceIds.map((surfaceId) => `\`${surfaceId}\``).join('、')}`);
    lines.push(`- 关联路由数：${moduleItem.routeCount}`);
    lines.push('- 职责：');
    moduleItem.responsibilities.forEach((item) => {
      lines.push(`  - ${item}`);
    });
    lines.push('- 主要服务边界：');
    moduleItem.primaryServiceBoundaries.forEach((item) => {
      lines.push(`  - ${item}`);
    });
    lines.push('- 关键文件：');
    moduleItem.keyFiles.forEach((filePath) => {
      lines.push(`  - \`${filePath}\``);
    });
    lines.push('');
  });

  lines.push('## 维护规则');
  lines.push('');
  artifact.maintenanceRules.forEach((rule) => {
    lines.push(`- ${rule}`);
  });
  lines.push('');

  return `${lines.join('\n')}`;
}

async function writeArtifactFile(relativePath: string, content: string) {
  const absolutePath = resolveRepoPath(relativePath);
  await mkdir(path.dirname(absolutePath), { recursive: true });
  await writeFile(absolutePath, content, 'utf8');
}

async function main() {
  await validateManifest(BACKEND_CAPABILITY_MANIFEST);

  const artifact = buildArtifact(BACKEND_CAPABILITY_MANIFEST);
  const jsonContent = `${JSON.stringify(artifact, null, 2)}\n`;
  const markdownContent = renderMarkdown(artifact);

  await writeArtifactFile(artifact.outputTargets.json, jsonContent);
  await writeArtifactFile(artifact.outputTargets.markdown, markdownContent);

  console.log(
    [
      `backend capability artifacts generated`,
      `json=${artifact.outputTargets.json}`,
      `markdown=${artifact.outputTargets.markdown}`,
      `routes=${artifact.summary.routeCount}`,
      `modules=${artifact.summary.moduleCount}`,
    ].join(' | '),
  );
}

void main().catch((error) => {
  console.error(error);
  process.exit(1);
});