import path from "node:path";
import { describe, expect, it } from "vitest";
import {
  applyPathPrepend,
  findPathKey,
  mergePathPrepend,
  normalizePathPrepend,
} from "./path-prepend.js";

const env = (value: Record<string, string>) => value;
const pathLine = (...parts: string[]) => parts.join(path.delimiter);

describe("path prepend helpers", () => {
  it.each([
    { env: env({ PATH: "/usr/bin" }), expected: "PATH" },
    { env: env({ Path: "/usr/bin" }), expected: "Path" },
    { env: env({ path: "/usr/bin" }), expected: "path" },
    { env: env({ PaTh: "/usr/bin" }), expected: "PaTh" },
    { env: env({ HOME: "/tmp" }), expected: "PATH" },
  ])("finds the PATH key for %j", ({ env, expected }) => {
    expect(findPathKey(env)).toBe(expected);
  });

  it("normalizes prepend lists by trimming, skipping blanks, and deduping", () => {
    expect(
      normalizePathPrepend([" /custom/bin ", "", " /custom/bin ", "/opt/bin", 42 as any]),
    ).toEqual(["/custom/bin", "/opt/bin"]);
    expect(normalizePathPrepend()).toEqual([]);
  });

  it.each([
    {
      existingPath: pathLine("/usr/bin", "/opt/bin"),
      prepend: ["/custom/bin", "/usr/bin"],
      expected: pathLine("/custom/bin", "/usr/bin", "/opt/bin"),
    },
    {
      existingPath: undefined,
      prepend: ["/custom/bin"],
      expected: "/custom/bin",
    },
    {
      existingPath: "/usr/bin",
      prepend: [],
      expected: "/usr/bin",
    },
    {
      existingPath: ` /usr/bin ${path.delimiter} ${path.delimiter} /opt/bin `,
      prepend: ["/custom/bin"],
      expected: pathLine("/custom/bin", "/usr/bin", "/opt/bin"),
    },
  ])("merges prepended paths for %j", ({ existingPath, prepend, expected }) => {
    expect(mergePathPrepend(existingPath, prepend)).toBe(expected);
  });

  it("applies prepends to the discovered PATH key and preserves existing casing", () => {
    const env = {
      Path: pathLine("/usr/bin", "/opt/bin"),
    };

    applyPathPrepend(env, ["/custom/bin", "/usr/bin"]);

    expect(env).toEqual({
      Path: pathLine("/custom/bin", "/usr/bin", "/opt/bin"),
    });
  });

  it.each([
    {
      env: env({ HOME: "/tmp/home" }),
      prepend: ["/custom/bin"],
      expected: env({ HOME: "/tmp/home" }),
    },
    {
      env: env({ path: "" }),
      prepend: ["/custom/bin"],
      expected: env({ path: "" }),
    },
    {
      env: env({ PATH: "/usr/bin" }),
      prepend: [],
      expected: env({ PATH: "/usr/bin" }),
    },
    {
      env: env({ PATH: "/usr/bin" }),
      prepend: undefined,
      expected: env({ PATH: "/usr/bin" }),
    },
  ])("respects requireExisting for %j", ({ env, prepend, expected }) => {
    applyPathPrepend(env, prepend, { requireExisting: true });
    expect(env).toEqual(expected);
  });

  it.each([
    {
      name: "creates PATH when prepends are provided and no path key exists",
      env: { HOME: "/tmp/home" },
      prepend: ["/custom/bin"],
      opts: undefined,
      expected: {
        HOME: "/tmp/home",
        PATH: "/custom/bin",
      },
    },
  ])("$name", ({ env, prepend, opts, expected }) => {
    applyPathPrepend(env, prepend, opts);
    expect(env).toEqual(expected);
  });
});