import { Command } from "commander";
import { checkbox, select, input } from "@inquirer/prompts";
import { resolve, basename } from "node:path";
import { writeFile } from "node:fs/promises";
import { resolveSource } from "../lib/config.js";
import { loadIndex } from "../lib/index-loader.js";
import { inferRepoUrl, cloneBlock, cleanupTemp } from "../lib/git.js";
import { applyTemplate } from "../lib/template.js";
import { compileAiRules } from "../lib/ai-compiler.js";
import type { Block, BrickJson } from "../types/index.js";

interface SelectedBlock {
  block: Block;
  branch: string;
  variantLabel: string;
}

const STYLES: { value: string; label: string }[] = [
  { value: "standard", label: "标准多模块 — 根 pom.xml 聚合所有积木子模块" },
  {
    value: "bom",
    label: "BOM 模式 — 根 pom + bom 子模块统一依赖版本管理",
  },
  { value: "simple", label: "简单模式 — 不生成根 pom，积木模块平铺" },
];

const AI_TOOLS: { value: string; label: string }[] = [
  { value: "claude", label: "Claude Code" },
  { value: "cursor", label: "Cursor" },
  { value: "copilot", label: "GitHub Copilot" },
  { value: "aider", label: "Aider" },
  { value: "generic", label: "通用（AI_CONTEXT.md）" },
];

export function registerCreate(program: Command): void {
  program
    .command("create <project-name>")
    .description("创建新项目")
    .action(async (projectName: string) => {
      try {
        await runCreate(projectName);
      } catch (err: unknown) {
        const msg = (err as Error).message ?? "";
        if (msg.includes("User force closed") || msg.includes("ExitPromptError")) {
          console.log("\n已取消。");
          process.exit(0);
        }
        throw err;
      }
    });
}

async function runCreate(projectName: string): Promise<void> {
      const cwd = process.cwd();

      // 1. Load index
      const source = resolveSource();
      console.log(`[1/7] 拉取积木索引...`);
      const index = await loadIndex(source);

      if (index.blocks.length === 0) {
        console.log("没有可用的积木。");
        return;
      }

      // 2. Interactive prompts
      // 2a. Select blocks
      const chosenNames = await checkbox({
        message: "选择要集成的积木（空格选择，回车确认）:",
        choices: index.blocks.map((b) => ({
          name: `${b.name} — ${b.description}`,
          value: b.name,
          checked: true,
        })),
      });

      if (chosenNames.length === 0) {
        console.log("未选择任何积木，已取消。");
        return;
      }

      const chosenBlocks = index.blocks.filter((b) =>
        chosenNames.includes(b.name)
      );

      // 2b. Resolve dependencies (auto-add missing)
      const resolved = resolveDeps(chosenBlocks, index.blocks);
      if (resolved.added.length > 0) {
        console.log(
          `  自动补全依赖：${resolved.added.map((b) => b.name).join(", ")}`
        );
      }

      // 2c. Select variant for blocks with multiple variants
      const selected: SelectedBlock[] = [];
      for (const block of resolved.all) {
        let branch = block.defaultBranch;
        let variantLabel = block.defaultBranch;

        if (block.variants.length > 1) {
          const chosen = await select({
            message: `为 ${block.name} 选择变体:`,
            choices: block.variants.map((v) => ({
              name: `${v.label} (${v.branch})`,
              value: v.branch,
            })),
            default: block.defaultBranch,
          });
          branch = chosen;
          variantLabel =
            block.variants.find((v) => v.branch === chosen)?.label ?? chosen;
        }

        selected.push({ block, branch, variantLabel });
      }

      // 2d. Project style
      const style = await select({
        message: "选择工程风格:",
        choices: STYLES,
        default: "standard",
      });

      // 2e. Variables
      const defaultPkg = `com.example.${projectName.replace(/[^a-zA-Z0-9]/g, "")}`;

      const basePackage = await input({
        message: "基础包名 (basePackage):",
        default: defaultPkg,
      });

      const groupId = await input({
        message: "Maven groupId:",
        default: basePackage,
      });

      const javaVersion = await input({
        message: "Java 版本:",
        default: "17",
      });

      // 2f. AI tool
      const aiTool = await select({
        message: "选择 AI 工具:",
        choices: AI_TOOLS,
        default: "claude",
      });

      // Summary
      console.log("\n--- 配置摘要 ---");
      console.log(`  项目名:     ${projectName}`);
      console.log(`  积木:       ${selected.map((s) => `${s.block.name} (${s.variantLabel})`).join(", ")}`);
      console.log(`  工程风格:   ${STYLES.find((s) => s.value === style)?.label}`);
      console.log(`  基础包名:   ${basePackage}`);
      console.log(`  groupId:    ${groupId}`);
      console.log(`  Java 版本:  ${javaVersion}`);
      console.log(`  AI 工具:    ${AI_TOOLS.find((t) => t.value === aiTool)?.label}`);
      console.log("-----------------\n");

      // 3. Clone blocks
      console.log("[2/7] 拉取积木仓库...");
      const blockDirs: { name: string; dir: string }[] = [];

      for (const sel of selected) {
        const url = inferRepoUrl(sel.block.name, sel.block.repo);
        console.log(`  clone ${url} (branch: ${sel.branch})...`);
        const dir = await cloneBlock(url, sel.branch);
        blockDirs.push({ name: sel.block.name, dir });
      }

      // 4. Apply templates
      console.log("[3/7] 生成项目源码...");
      const targetDir = resolve(cwd, projectName);
      const vars: Record<string, string> = {
        basePackage,
        groupId,
        projectName,
        javaVersion,
      };

      for (const bd of blockDirs) {
        await applyTemplate(bd.dir, targetDir, vars);
      }

      // 5. Generate AI rules
      console.log("[4/7] 生成 AI 规则文件...");
      await compileAiRules(blockDirs, targetDir, aiTool);

      // 6. Generate root pom.xml
      console.log("[5/7] 生成根 pom.xml...");
      if (style !== "simple") {
        const rootPom = buildRootPom(
          projectName,
          groupId,
          javaVersion,
          selected,
          style
        );
        await writeFile(resolve(targetDir, "pom.xml"), rootPom, "utf-8");
      }

      // 7. Generate brick.json
      console.log("[6/7] 生成 brick.json...");
      const brickJson: BrickJson = {
        projectName,
        basePackage,
        javaVersion,
        aiTool,
        style,
        blocks: selected.map((s) => ({
          name: s.block.name,
          variant: s.variantLabel,
          version: s.block.version,
        })),
      };
      await writeFile(
        resolve(targetDir, "brick.json"),
        JSON.stringify(brickJson, null, 2),
        "utf-8"
      );

      // 8. Cleanup temp dirs
      console.log("[7/7] 清理临时文件...");
      for (const bd of blockDirs) {
        await cleanupTemp(bd.dir);
      }

      console.log(`\n项目已创建：${targetDir}`);
      console.log("Done!");
}

function resolveDeps(
  chosen: Block[],
  all: Block[]
): { all: Block[]; added: Block[] } {
  const blockMap = new Map(all.map((b) => [b.name, b]));
  const result = new Map(chosen.map((b) => [b.name, b]));
  const added: Block[] = [];

  // Iteratively resolve dependencies
  let changed = true;
  while (changed) {
    changed = false;
    for (const block of [...result.values()]) {
      for (const depName of block.dependsOn) {
        if (!result.has(depName)) {
          const dep = blockMap.get(depName);
          if (dep) {
            result.set(depName, dep);
            added.push(dep);
            changed = true;
          } else {
            process.stderr.write(
              `Warning: Dependency ${depName} not found in index\n`
            );
          }
        }
      }
    }
  }

  return { all: [...result.values()], added };
}

function buildRootPom(
  projectName: string,
  groupId: string,
  javaVersion: string,
  selected: SelectedBlock[],
  style: string
): string {
  const modules = selected
    .map((s) => `        <module>${projectName}-common-${s.block.module}</module>`)
    .join("\n");

  if (style === "bom") {
    return [
      '<?xml version="1.0" encoding="UTF-8"?>',
      '<project xmlns="http://maven.apache.org/POM/4.0.0"',
      '         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"',
      '         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">',
      '    <modelVersion>4.0.0</modelVersion>',
      "",
      `    <groupId>${groupId}</groupId>`,
      `    <artifactId>${projectName}</artifactId>`,
      "    <version>0.0.0</version>",
      "    <packaging>pom</packaging>",
      "",
      `    <name>${projectName}</name>`,
      "",
      "    <properties>",
      `        <java.version>${javaVersion}</java.version>`,
      `        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>`,
      `        <brick.version>0.0.0</brick.version>`,
      "    </properties>",
      "",
      "    <dependencyManagement>",
      "        <dependencies>",
      ...selected.map(
        (s) =>
          `            <dependency>\n` +
          `                <groupId>${groupId}</groupId>\n` +
          `                <artifactId>${projectName}-common-${s.block.module}</artifactId>\n` +
          `                <version>${"$"}{brick.version}</version>\n` +
          `            </dependency>`
      ),
      "        </dependencies>",
      "    </dependencyManagement>",
      "",
      "    <modules>",
      `        <module>${projectName}-common-bom</module>`,
      modules,
      "    </modules>",
      "</project>",
    ].join("\n");
  }

  // standard
  return [
    '<?xml version="1.0" encoding="UTF-8"?>',
    '<project xmlns="http://maven.apache.org/POM/4.0.0"',
    '         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"',
    '         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">',
    '    <modelVersion>4.0.0</modelVersion>',
    "",
    `    <groupId>${groupId}</groupId>`,
    `    <artifactId>${projectName}</artifactId>`,
    "    <version>0.0.0</version>",
    "    <packaging>pom</packaging>",
    "",
    `    <name>${projectName}</name>`,
    "",
    "    <properties>",
    `        <java.version>${javaVersion}</java.version>`,
    `        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>`,
    "    </properties>",
    "",
    "    <modules>",
    modules,
    "    </modules>",
    "</project>",
  ].join("\n");
}