// Config Unit Tests — getServersForPath() merge semantics, mtime caching,
// and graceful fallback on parse errors.
import { describe, it, beforeEach, afterEach } from "node:test";
import * as assert from "node:assert/strict";
import * as fs from "node:fs";
import * as os from "node:os";
import * as path from "node:path";
import { getServersForPath, clearConfigCache } from "../../src/config.ts";
import { servers as builtinServers } from "../../server.ts";

let tmpDir: string;

beforeEach(() => {
  tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), "pi-lsp-config-test-"));
  clearConfigCache();
});

afterEach(() => {
  fs.rmSync(tmpDir, { recursive: true, force: true });
  clearConfigCache();
});

function writeConfig(dir: string, content: unknown): void {
  fs.writeFileSync(path.join(dir, ".pi-lsp.json"), JSON.stringify(content));
}

describe("getServersForPath", () => {
  it("returns built-in servers when no config file is found", () => {
    // tmpDir lives under /tmp; no ancestor will have .pi-lsp.json.
    const result = getServersForPath(tmpDir);
    assert.deepStrictEqual(
      result.map((s) => s.id),
      builtinServers.map((s) => s.id),
    );
  });

  it("appends a new server entry from config", () => {
    writeConfig(tmpDir, {
      servers: [
        {
          id: "rust-analyzer",
          match: ["rs"],
          command: "rust-analyzer",
          args: [],
          rootMarkers: ["Cargo.toml"],
          languageId: "rust",
        },
      ],
    });
    const result = getServersForPath(tmpDir);
    const rust = result.find((s) => s.id === "rust-analyzer");
    assert.ok(rust, "rust-analyzer should be present");
    assert.deepStrictEqual(rust!.match, ["rs"]);
    // Built-ins are still there
    assert.ok(result.find((s) => s.id === "gopls"));
  });

  it("shallow-merges overrides into existing built-in servers", () => {
    writeConfig(tmpDir, {
      servers: [{ id: "gopls", args: ["-vv"] }],
    });
    const result = getServersForPath(tmpDir);
    const gopls = result.find((s) => s.id === "gopls")!;
    assert.deepStrictEqual(gopls.args, ["-vv"]);
    // Other fields preserved from built-in
    assert.strictEqual(gopls.command, "gopls");
    assert.deepStrictEqual(gopls.match, ["go"]);
  });

  it("filters out servers listed in `disable`", () => {
    writeConfig(tmpDir, { disable: ["oxlint", "gopls"] });
    const result = getServersForPath(tmpDir);
    assert.ok(!result.some((s) => s.id === "oxlint"));
    assert.ok(!result.some((s) => s.id === "gopls"));
    assert.ok(result.some((s) => s.id === "pyright"));
  });

  it("walks upward to find config in an ancestor directory", () => {
    writeConfig(tmpDir, { disable: ["oxlint"] });
    const sub = path.join(tmpDir, "a", "b", "c");
    fs.mkdirSync(sub, { recursive: true });
    const result = getServersForPath(sub);
    assert.ok(!result.some((s) => s.id === "oxlint"));
  });

  it("accepts a file path and walks from its directory", () => {
    writeConfig(tmpDir, { disable: ["oxlint"] });
    const file = path.join(tmpDir, "src", "main.go");
    fs.mkdirSync(path.dirname(file), { recursive: true });
    fs.writeFileSync(file, "package main");
    const result = getServersForPath(file);
    assert.ok(!result.some((s) => s.id === "oxlint"));
  });

  it("falls back to built-ins on invalid JSON", () => {
    fs.writeFileSync(path.join(tmpDir, ".pi-lsp.json"), "{ not valid");
    const result = getServersForPath(tmpDir);
    assert.deepStrictEqual(
      result.map((s) => s.id),
      builtinServers.map((s) => s.id),
    );
  });

  it("falls back to built-ins when a new server is missing required fields", () => {
    writeConfig(tmpDir, {
      servers: [{ id: "incomplete", match: ["foo"] }],
    });
    const result = getServersForPath(tmpDir);
    assert.deepStrictEqual(
      result.map((s) => s.id),
      builtinServers.map((s) => s.id),
    );
  });

  it("invalidates cache on mtime change", () => {
    writeConfig(tmpDir, { disable: ["oxlint"] });
    let result = getServersForPath(tmpDir);
    assert.ok(!result.some((s) => s.id === "oxlint"));

    // Rewrite With Different Content And Bump mtime
    const cfgPath = path.join(tmpDir, ".pi-lsp.json");
    fs.writeFileSync(cfgPath, JSON.stringify({ disable: ["gopls"] }));
    const future = new Date(Date.now() + 5000);
    fs.utimesSync(cfgPath, future, future);

    result = getServersForPath(tmpDir);
    assert.ok(result.some((s) => s.id === "oxlint"));
    assert.ok(!result.some((s) => s.id === "gopls"));
  });
});