import { mkdir, writeFile, readFile, rename } from "node:fs/promises";
import { join } from "node:path";
import type { RuneConfig, DocumentConfig } from "../../src/types.ts";
import type { AgentRunner, AgentResult } from "./runner.ts";
import { getChangeDir, getArchiveDir } from "../../src/core/config.ts";
import { parseTasks } from "../../src/core/task-parser.ts";

export class CommandLevelRunner implements AgentRunner {
  readonly tier = 1;

  async runPlan(
    projectDir: string,
    changeName: string,
    docName: string,
    config: RuneConfig,
  ): Promise<AgentResult> {
    const changeDir = getChangeDir(projectDir, changeName);
    await mkdir(changeDir, { recursive: true });

    const planStage = config.stages.plan;
    if (!planStage) {
      throw new Error("plan 阶段未配置");
    }

    const docConfig = planStage.documents.find((d) => d.name === docName);
    if (!docConfig) {
      throw new Error(`文档 "${docName}" 未在 plan.documents 中配置`);
    }

    const content = this.renderDocument(docConfig, changeName);
    const filePath = join(changeDir, `${docName}.md`);
    await writeFile(filePath, content);

    return { files: [`${docName}.md`] };
  }

  async runBuild(
    projectDir: string,
    changeName: string,
    _config: RuneConfig,
  ): Promise<AgentResult> {
    const changeDir = getChangeDir(projectDir, changeName);
    const taskPath = join(changeDir, "task.md");

    let taskContent: string;
    try {
      taskContent = await readFile(taskPath, "utf-8");
    } catch {
      throw new Error(`变更 "${changeName}" 的 task.md 不存在，请先完成规划`);
    }

    const tasks = parseTasks(taskContent);
    const pending = tasks.filter((t) => !t.checked);

    if (pending.length === 0) {
      return { files: [] };
    }

    const files: string[] = [];
    for (const task of pending) {
      const oldLine = `- [ ] ${task.text}`;
      const newLine = `- [x] ${task.text}`;
      taskContent = taskContent.replace(oldLine, newLine);
      const implFile = `${task.text
        .replace(/[^a-zA-Z\u4e00-\u9fa5]+/g, "-")
        .replace(/^-|-$/g, "")
        .toLowerCase()}.ts`;
      await writeFile(join(changeDir, implFile), `// ${task.text}\n`);
      files.push(implFile);
    }

    await writeFile(taskPath, taskContent);
    files.push("task.md");

    return { files };
  }

  async runArchive(
    projectDir: string,
    changeName: string,
    _config: RuneConfig,
  ): Promise<AgentResult> {
    const changeDir = getChangeDir(projectDir, changeName);
    const taskPath = join(changeDir, "task.md");

    try {
      const taskContent = await readFile(taskPath, "utf-8");
      const tasks = parseTasks(taskContent);
      const pending = tasks.filter((t) => !t.checked);

      if (pending.length > 0) {
        throw new Error(`变更 "${changeName}" 存在 ${pending.length} 个未完成任务，无法归档`);
      }
    } catch (e) {
      if (e instanceof Error && e.message.includes("未完成任务")) {
        throw e;
      }
    }

    const today = new Date().toISOString().slice(0, 10);
    const archiveDir = getArchiveDir(projectDir);
    await mkdir(archiveDir, { recursive: true });
    const dest = join(archiveDir, `${today}-${changeName}`);
    await rename(changeDir, dest);

    return { files: [] };
  }

  private renderDocument(doc: DocumentConfig, changeName: string): string {
    if (doc.template) {
      return doc.template.replace(/\{\{change-name\}\}/g, changeName) + "\n";
    }
    return `# ${doc.name}\n\n${doc.prompt}\n`;
  }
}

export function createRunner(): AgentRunner {
  return new CommandLevelRunner();
}