import { describe, it } from "node:test";
import assert from "node:assert";
import { resolveConfig } from "../src/config.js";

describe("resolveConfig", () => {
  it("returns empty config when no sources are present", () => {
    const config = resolveConfig({
      existsSync: () => false,
      whichSync: () => undefined,
    });
    assert.deepStrictEqual(config.paths, {});
    assert.strictEqual(config.defaultClient, undefined);
  });

  it("loads config from file", () => {
    const config = resolveConfig({
      existsSync: () => true,
      readFileSync: () =>
        JSON.stringify({
          paths: { codex: "/file/codex", claude: "/file/claude" },
          defaultClient: "claude",
        }),
      whichSync: () => undefined,
    });
    assert.strictEqual(config.paths.codex, "/file/codex");
    assert.strictEqual(config.paths.claude, "/file/claude");
    assert.strictEqual(config.defaultClient, "claude");
  });

  it("overrides file config with env vars", () => {
    const config = resolveConfig({
      env: { AI_CLI_CODEX_PATH: "/env/codex" },
      existsSync: () => true,
      readFileSync: () => JSON.stringify({ paths: { codex: "/file/codex" } }),
      whichSync: () => undefined,
    });
    assert.strictEqual(config.paths.codex, "/env/codex");
  });

  it("overrides env vars with CLI flags", () => {
    const config = resolveConfig({
      flags: { "codex-path": "/flag/codex" },
      env: { AI_CLI_CODEX_PATH: "/env/codex" },
      existsSync: () => true,
      readFileSync: () => JSON.stringify({ paths: { codex: "/file/codex" } }),
      whichSync: () => undefined,
    });
    assert.strictEqual(config.paths.codex, "/flag/codex");
  });

  it("falls back to PATH detection when config file is missing", () => {
    const config = resolveConfig({
      existsSync: () => false,
      whichSync: (cmd) =>
        cmd === "opencode" ? "/usr/bin/opencode" : undefined,
    });
    assert.strictEqual(config.paths.opencode, "/usr/bin/opencode");
    assert.strictEqual(config.paths.codex, undefined);
    assert.strictEqual(config.paths.claude, undefined);
  });

  it("respects full priority ordering: flag > env > file > PATH", () => {
    const config = resolveConfig({
      flags: {
        "codex-path": "/flag/codex",
        "claude-path": "/flag/claude",
        "opencode-path": "/flag/opencode",
        "default-client": "opencode",
      },
      env: {
        AI_CLI_CODEX_PATH: "/env/codex",
        AI_CLI_CLAUDE_PATH: "/env/claude",
        AI_CLI_OPENCODE_PATH: "/env/opencode",
        AI_CLI_DEFAULT_CLIENT: "claude",
      },
      existsSync: () => true,
      readFileSync: () =>
        JSON.stringify({
          paths: {
            codex: "/file/codex",
            claude: "/file/claude",
            opencode: "/file/opencode",
          },
          defaultClient: "codex",
        }),
      whichSync: (cmd) => `/path/${cmd}`,
    });
    assert.strictEqual(config.paths.codex, "/flag/codex");
    assert.strictEqual(config.paths.claude, "/flag/claude");
    assert.strictEqual(config.paths.opencode, "/flag/opencode");
    assert.strictEqual(config.defaultClient, "opencode");
  });

  it("uses env var for default client when no flag is given", () => {
    const config = resolveConfig({
      env: { AI_CLI_DEFAULT_CLIENT: "claude" },
      existsSync: () => false,
      whichSync: () => undefined,
    });
    assert.strictEqual(config.defaultClient, "claude");
  });

  it("uses file default client when no env var is given", () => {
    const config = resolveConfig({
      existsSync: () => true,
      readFileSync: () => JSON.stringify({ defaultClient: "codex" }),
      whichSync: () => undefined,
    });
    assert.strictEqual(config.defaultClient, "codex");
  });

  it("ignores invalid defaultClient from file", () => {
    const config = resolveConfig({
      existsSync: () => true,
      readFileSync: () => JSON.stringify({ defaultClient: "foo" }),
      whichSync: () => undefined,
    });
    assert.strictEqual(config.defaultClient, undefined);
  });

  it("ignores invalid defaultClient from env var", () => {
    const config = resolveConfig({
      env: { AI_CLI_DEFAULT_CLIENT: "bar" },
      existsSync: () => false,
      whichSync: () => undefined,
    });
    assert.strictEqual(config.defaultClient, undefined);
  });

  it("ignores invalid defaultClient from flag", () => {
    const config = resolveConfig({
      flags: { "default-client": "baz" },
      existsSync: () => false,
      whichSync: () => undefined,
    });
    assert.strictEqual(config.defaultClient, undefined);
  });
});