import * as fs from "node:fs";
import * as path from "node:path";
import * as os from "node:os";
import { ResearcherAgent } from "../agents/researcher.js";
import { AgentContext } from "../agents/base.js";
import { IntelligenceBackend, BackendRequest, BackendResult } from "../backends/types.js";
import { emptyTokenUsage } from "../backends/types.js";

class MockBackend implements IntelligenceBackend {
  readonly name = "mock";
  readonly type = "llm" as const;
  async isAvailable(): Promise<boolean> { return true; }
  async execute(request: BackendRequest): Promise<BackendResult> {
    return {
      success: true,
      output: `Mock backend executed: ${request.task.slice(0, 50)}`,
      artifacts: [],
      decisions: [],
      escalations: [],
      usage: emptyTokenUsage(),
    };
  }
}

function createTempDir(): string {
  return fs.mkdtempSync(path.join(os.tmpdir(), "ciagent-researcher-test-"));
}

function cleanup(dir: string): void {
  fs.rmSync(dir, { recursive: true, force: true });
}

function makeContext(dir: string, backend?: IntelligenceBackend): AgentContext {
  return {
    project_path: dir,
    phase: 1,
    stage: "research",
    specification: "Build a REST API for task management",
    config_path: path.join(dir, ".ciagent", "config.json"),
    backend,
  };
}

function setupCIAgentDir(dir: string): void {
  const ciDir = path.join(dir, ".ciagent");
  fs.mkdirSync(ciDir, { recursive: true });
  fs.writeFileSync(path.join(ciDir, "config.json"), '{"projects":[],"active_project":""}');
}

function writeProjectMd(dir: string): void {
  const ciDir = path.join(dir, ".ciagent");
  const content = [
    "# Task API",
    "",
    "## What This Is",
    "",
    "A REST API for managing tasks",
    "",
    "## Requirements",
    "",
    "### Validated",
    "",
    "- ✓ User authentication",
    "",
    "### Active",
    "",
    "- [ ] Task CRUD",
    "",
    "### Out of Scope",
    "",
    "- Admin dashboard",
    "",
    "## Context",
    "",
    "Node.js project",
    "",
    "## Constraints",
    "",
    "- Must use Node.js",
    "",
    "## Key Decisions",
    "",
    "| Decision | Rationale | Outcome |",
    "|----------|-----------|---------|",
  ].join("\n");
  fs.writeFileSync(path.join(ciDir, "PROJECT.md"), content);
}

function writeArchitectureMd(dir: string): void {
  const ciDir = path.join(dir, ".ciagent");
  const content = [
    "# Architecture",
    "",
    "## Overview",
    "",
    "Task management system architecture",
    "",
    "## Components",
    "",
    "### Core",
    "- **Description**: Core module",
    "- **Boundaries**: src/core/ — internal module",
    "- **Depends on**: None",
    "",
    "## Data Flow",
    "",
    "Request → Handler → Service → Database",
    "",
    "## Build Order",
    "",
    "1. Build core module",
  ].join("\n");
  fs.writeFileSync(path.join(ciDir, "ARCHITECTURE.md"), content);
}

function setupSourceDir(dir: string): void {
  const srcDir = path.join(dir, "src");
  fs.mkdirSync(srcDir, { recursive: true });
  fs.mkdirSync(path.join(srcDir, "core"), { recursive: true });
  fs.mkdirSync(path.join(srcDir, "agents"), { recursive: true });
  fs.writeFileSync(path.join(srcDir, "core", "index.ts"), "export {};\n");
  fs.writeFileSync(path.join(srcDir, "agents", "base.ts"), "export {};\n");
}

describe("ResearcherAgent", () => {
  let dir: string;

  beforeEach(() => {
    dir = createTempDir();
  });

  afterEach(() => {
    cleanup(dir);
  });

  it("reads .ciagent/ files without backend", async () => {
    setupCIAgentDir(dir);
    writeProjectMd(dir);
    writeArchitectureMd(dir);

    const researcher = new ResearcherAgent();
    const result = await researcher.execute(makeContext(dir));
    expect(result.success).toBe(true);
    expect(result.output).toContain("findingsCount");
  });

  it("only modifies .ciagent/ files", async () => {
    setupCIAgentDir(dir);
    writeProjectMd(dir);
    writeArchitectureMd(dir);
    setupSourceDir(dir);

    const srcDir = path.join(dir, "src");
    const filesBefore = new Set<string>();
    function collectFiles(d: string): void {
      for (const entry of fs.readdirSync(d, { withFileTypes: true })) {
        const full = path.join(d, entry.name);
        if (entry.isDirectory() && entry.name !== "node_modules") {
          collectFiles(full);
        } else {
          filesBefore.add(full);
        }
      }
    }
    collectFiles(srcDir);

    const researcher = new ResearcherAgent();
    await researcher.execute(makeContext(dir));

    collectFiles(srcDir);
    for (const f of filesBefore) {
      expect(fs.existsSync(f)).toBe(true);
    }
  });

  it("updates ARCHITECTURE.md from source scan", async () => {
    setupCIAgentDir(dir);
    writeProjectMd(dir);
    setupSourceDir(dir);

    const researcher = new ResearcherAgent();
    const result = await researcher.execute(makeContext(dir));

    if (result.success) {
      const parsed = JSON.parse(result.output);
      expect(parsed.filesUpdated).toContain(".ciagent/ARCHITECTURE.md");
    }
  });

  it("delegates to backend when available", async () => {
    setupCIAgentDir(dir);
    const mockBackend = new MockBackend();
    const researcher = new ResearcherAgent();
    const result = await researcher.execute(makeContext(dir, mockBackend));
    expect(result.success).toBe(true);
    expect(result.output).toContain("Mock backend executed");
  });

  it("has correct agent name", () => {
    const researcher = new ResearcherAgent();
    expect(researcher.name).toBe("researcher");
  });

  it("has correct workflow", () => {
    const researcher = new ResearcherAgent();
    expect(researcher.workflow).toBe("research");
  });
});