import { afterEach, expect, test } from "bun:test";
import { mkdirSync, mkdtempSync, rmSync, writeFileSync } from "node:fs";
import { tmpdir } from "node:os";
import { join } from "node:path";
import { parse } from "@wrnexus/syntax";
import { generate } from "../src/codegen.ts";

const ROOT_TSCONFIG = join(import.meta.dir, "../../../tsconfig.json").replace(/\\/g, "/");
// The repo's own tsc, not a `bunx`-fetched one — `bunx tsc` can resolve an
// unrelated TypeScript version that doesn't understand this repo's tsconfig
// options (observed: it rejected `ignoreDeprecations: "6.0"` and couldn't
// find the `bun` type-definition entry point), unlike `bun run typecheck`,
// which uses this same local binary.
const LOCAL_TSC = join(import.meta.dir, "../../../node_modules/.bin/tsc").replace(/\\/g, "/");
// `types`/`typeRoots` in an extended tsconfig resolve relative to the config
// file that's actually invoked (our temp one), not the base file — so the
// ambient `bun` types need an explicit path back to the repo's node_modules.
const TYPE_ROOTS = join(import.meta.dir, "../../../node_modules/@types").replace(/\\/g, "/");

const roots: string[] = [];
afterEach(() => {
  for (const root of roots.splice(0)) rmSync(root, { recursive: true, force: true });
});

/**
 * Runs the real TypeScript compiler over a generated server module. Proves
 * the emitted `__wrnexusSsrBindings` annotation (and everything else in the
 * module) actually type-checks — string-containment assertions alone can't
 * catch a declared type that omits a field every emitted object literal has.
 */
function typecheckGenerated(source: string): { ok: boolean; output: string } {
  const root = mkdtempSync(join(tmpdir(), "wrnexus-ssr-tsc-"));
  roots.push(root);
  const file = join(root, "page.ts");
  writeFileSync(file, source);
  // Reuse the repo's own tsconfig (paths, lib, types, jsx, ...) so this only
  // checks the one file we care about instead of hand-duplicating the whole
  // compiler configuration (and drifting from it over time).
  writeFileSync(
    join(root, "tsconfig.json"),
    JSON.stringify({
      extends: ROOT_TSCONFIG,
      compilerOptions: { noEmit: true, typeRoots: [TYPE_ROOTS] },
      include: ["page.ts"],
    }),
  );
  const result = Bun.spawnSync([LOCAL_TSC, "--project", join(root, "tsconfig.json")], {
    cwd: root,
    stdout: "pipe",
    stderr: "pipe",
  });
  const output = `${result.stdout?.toString() ?? ""}${result.stderr?.toString() ?? ""}`;
  return { ok: result.exitCode === 0, output };
}

function serverModule(inner: string): string {
  return generate(
    parse(`page Repro {
  ssr {
${inner}
  }

  view { <main><p api="ssrUsers">loading</p></main> }
}
`),
  );
}

test("a sectioned ssr block binds the payload to data", () => {
  const generated = serverModule(`    api ssrUsers GET /api/users {
      response {
        return data.users.length
      }
    }`);

  expect(generated).toContain("data.users.length");
});

test("a legacy ssr block is unchanged", () => {
  const generated = serverModule(`    api ssrUsers GET /api/users {
      return users.length
    }`);

  expect(generated).toContain("users.length");
});

test("an ssr block with an error section emits the error body and binds status/message/data", () => {
  const generated = serverModule(`    api ssrUsers GET /api/users {
      response {
        return data.users.length
      }
      error {
        return message + status + data
      }
    }`);

  expect(generated).toContain('"errorBody"');
  expect(generated).toContain("return message + status + data");
  expect(generated).toContain("const status = $status");
  expect(generated).toContain("const message = $message");
  expect(generated).toContain("const data = $data");
  expect(generated).toContain("__wrnexusEvalError");
});

test("an ssr block without an error section emits no catch entry for that binding", () => {
  const generated = serverModule(`    api ssrUsers GET /api/users {
      response {
        return data.users.length
      }
    }`);

  expect(generated).not.toContain('"errorBody"');
});

test("tsc: a sectioned ssr block's generated module has no diagnostics", () => {
  const generated = serverModule(`    api ssrUsers GET /api/users {
      response {
        return data.users.length
      }
      error {
        return message + status + data
      }
    }`);

  const { ok, output } = typecheckGenerated(generated);

  expect(output.trim()).toBe("");
  expect(ok).toBe(true);
});

test("an ssr block used in {#each} with an error section runs the error body on failure", async () => {
  const generated = generate(
    parse(`page Repro {
  ssr {
    api ssrUsers GET /api/users {
      response {
        return data.users
      }
      error {
        return ["fallback"]
      }
    }
  }

  view { <main>{#each ssrUsers as u}<p>{u}</p>{/each}</main> }
}
`),
  );

  const root = mkdtempSync(join(tmpdir(), "wrnexus-ssr-each-"));
  roots.push(root);
  mkdirSync(root, { recursive: true });
  const file = join(root, "page.ts");
  writeFileSync(file, generated);

  const mod = await import(`${file.replace(/\\/g, "/")}?t=${Date.now()}`);
  const html = await mod.default({
    req: { url: "http://localhost/", headers: new Headers() },
    cookies: {},
    session: {},
    localStorage: {},
    __wrnexusCallApi: async () => {
      throw new Error("boom");
    },
  });

  expect(html).toContain("fallback");
});

test("an ssr block's response body error is not swallowed by the error section", async () => {
  const generated = generate(
    parse(`page Repro {
  ssr {
    api ssrUsers GET /api/users {
      response {
        return data.users.missing.length
      }
      error {
        return ["fallback"]
      }
    }
  }

  view { <main>{#each ssrUsers as u}<p>{u}</p>{/each}</main> }
}
`),
  );

  const root = mkdtempSync(join(tmpdir(), "wrnexus-ssr-response-throws-"));
  roots.push(root);
  mkdirSync(root, { recursive: true });
  const file = join(root, "page.ts");
  writeFileSync(file, generated);

  const mod = await import(`${file.replace(/\\/g, "/")}?t=${Date.now()}`);

  await expect(
    mod.default({
      req: { url: "http://localhost/", headers: new Headers() },
      cookies: {},
      session: {},
      localStorage: {},
      __wrnexusCallApi: async () => ({ users: [] }),
    }),
  ).rejects.toThrow();
});

test("an ssr block still runs the error body on a genuine transport failure", async () => {
  const generated = generate(
    parse(`page Repro {
  ssr {
    api ssrUsers GET /api/users {
      response {
        return data.users.length
      }
      error {
        return ["fallback"]
      }
    }
  }

  view { <main>{#each ssrUsers as u}<p>{u}</p>{/each}</main> }
}
`),
  );

  const root = mkdtempSync(join(tmpdir(), "wrnexus-ssr-transport-fails-"));
  roots.push(root);
  mkdirSync(root, { recursive: true });
  const file = join(root, "page.ts");
  writeFileSync(file, generated);

  const mod = await import(`${file.replace(/\\/g, "/")}?t=${Date.now()}`);
  const html = await mod.default({
    req: { url: "http://localhost/", headers: new Headers() },
    cookies: {},
    session: {},
    localStorage: {},
    __wrnexusCallApi: async () => {
      throw new Error("boom");
    },
  });

  expect(html).toContain("fallback");
});

test("an ssr block used in {#each} without an error section still propagates a failure", async () => {
  const generated = generate(
    parse(`page Repro {
  ssr {
    api ssrUsers GET /api/users {
      response {
        return data.users
      }
    }
  }

  view { <main>{#each ssrUsers as u}<p>{u}</p>{/each}</main> }
}
`),
  );

  const root = mkdtempSync(join(tmpdir(), "wrnexus-ssr-each-propagate-"));
  roots.push(root);
  mkdirSync(root, { recursive: true });
  const file = join(root, "page.ts");
  writeFileSync(file, generated);

  const mod = await import(`${file.replace(/\\/g, "/")}?t=${Date.now()}`);

  await expect(
    mod.default({
      req: { url: "http://localhost/", headers: new Headers() },
      cookies: {},
      session: {},
      localStorage: {},
      __wrnexusCallApi: async () => {
        throw new Error("boom");
      },
    }),
  ).rejects.toThrow("boom");
});