import { Request, Response, NextFunction } from 'express';
import assert from 'node:assert/strict';
import { afterEach, beforeEach, describe, it, mock } from 'node:test';
import {
  Handler,
  HandlersInput,
  GetItemHandler,
  GetCollectionHandler,
  UpdateItemHandler,
  DeleteItemHandler,
  CreateItemHandler,
} from '../src/handler.js';
import { BadRequestError } from '../src/httpErrors.js';

describe('Handler', () => {
  beforeEach(() => {
    // Disable debug logging to keep the test output clean.
    mock.method(global.console, 'debug', () => {});
  });

  afterEach(() => {
    mock.reset();
  });

  describe('constructor', () => {
    it('returns a Handler', () => {
      const itemHandler = new Handler('/', {});

      assert.ok(itemHandler instanceof Handler);
    });

    it('validates path', () => {
      const paths: [string, boolean][] = [
        ['', false],
        ['invalid', false],
        ['/', true],
        ['/bar', true],
        ['/bar/', false],
        ['/foo/:bar', true],
        ['/foo/:bar/', false],
        ['/foo/:bar/spam/:baz', true],
        ['/foo/:bar/:spam', true],
      ];

      for (const [path, valid] of paths) {
        if (valid) {
          assert.doesNotThrow(() => new Handler(path, {}));
        } else {
          assert.throws(() => new Handler(path, {}));
        }
      }
    });

    it('validates configuration', () => {
      const getItem = (() => {}) as unknown as GetItemHandler;
      const updateItem = (() => {}) as unknown as UpdateItemHandler;
      const deleteItem = (() => {}) as unknown as DeleteItemHandler;
      const getCollection = (() => {}) as unknown as GetCollectionHandler;
      const createItem = (() => {}) as unknown as CreateItemHandler;

      const paths: [string, HandlersInput, boolean][] = [
        ['/foo', { getItem }, true],
        ['/foo', { getCollection }, true],
        ['/foo', { getItem, getCollection }, false],
        ['/foo', { updateItem, createItem }, false],
        ['/foo', { deleteItem, createItem }, false],
        ['/foo/:bar', { getItem, getCollection }, true],
        ['/foo/:bar', { getItem, updateItem, deleteItem, createItem, getCollection }, true],
      ];

      for (const [path, handlers, valid] of paths) {
        if (valid) {
          assert.doesNotThrow(() => new Handler(path, handlers));
        } else {
          assert.throws(() => new Handler(path, handlers));
        }
      }
    });
  });

  describe('generate', () => {
    async function executeHandler(
      handler: (req: Request, res: Response, callback: NextFunction) => Promise<void>,
      request: Record<string, unknown> = {},
    ) {
      let body: Record<string, unknown> = {};
      let statusCode = 0;

      const response = {
        status: (receivedStatusCode: number) => ({
          send: (receivedBody: Record<string, unknown>) => {
            body = receivedBody;
            statusCode = receivedStatusCode;
          },
        }),
        statusCode: 0,
        locals: {
          credentials: { foo: 'bar' },
        },
      } as unknown as Response;

      await handler(request as unknown as Request, response, () => {});

      return { body, statusCode };
    }

    it('returns a router', async () => {
      const handler = new Handler('/foo/:bar', {
        getCollection: () => Promise.resolve({ info: {}, data: [] }),
        getItem: () => Promise.resolve({ fields: {}, relations: [] }),
        createItem: () => Promise.resolve({ fields: {}, path: '/' }),
        updateItem: () => Promise.resolve({ fields: {}, relations: [] }),
        deleteItem: () => Promise.resolve(),
      });

      const router = handler.generate();
      const routes = router.stack;

      assert.equal(routes.length, 5);
      assert.equal(routes[0]!.route!.path, '/foo');
      assert.equal((routes[0]!.route! as any).methods.get, true);
      assert.equal(routes[1]!.route!.path, '/foo');
      assert.equal((routes[1]!.route! as any).methods.post, true);
      assert.equal(routes[2]!.route!.path, '/foo/:bar');
      assert.equal((routes[2]!.route! as any).methods.get, true);
      assert.equal(routes[3]!.route!.path, '/foo/:bar');
      assert.equal((routes[3]!.route! as any).methods.patch, true);
      assert.equal(routes[4]!.route!.path, '/foo/:bar');
      assert.equal((routes[4]!.route! as any).methods.delete, true);

      // GetCollection.
      assert.deepEqual(await executeHandler(routes[0]!.route!.stack[0]!.handle), {
        body: { info: {}, data: [] },
        statusCode: 200,
      });

      // CreateItem.
      assert.deepEqual(await executeHandler(routes[1]!.route!.stack[0]!.handle, { body: { foo: 'bar' } }), {
        body: { fields: {}, path: '/' },
        statusCode: 201,
      });

      // GetItem.
      assert.deepEqual(await executeHandler(routes[2]!.route!.stack[0]!.handle), {
        body: { fields: {}, relations: [] },
        statusCode: 200,
      });

      // UpdateItem.
      assert.deepEqual(await executeHandler(routes[3]!.route!.stack[0]!.handle, { body: { foo: 'bar' } }), {
        body: { fields: {}, relations: [] },
        statusCode: 200,
      });

      // DeleteItem.
      assert.deepEqual(await executeHandler(routes[4]!.route!.stack[0]!.handle), {
        body: null,
        statusCode: 204,
      });
    });

    it('uses pathWithIdentifier as is when appropriate', async () => {
      const handler = new Handler('/foo/:bar/baz', {
        getCollection: () => Promise.resolve({ info: {}, data: [] }),
      });

      const router = handler.generate();
      const routes = router.stack;

      assert.equal(routes.length, 1);
      assert.equal(routes[0]!.route!.path, '/foo/:bar/baz');
      assert.equal((routes[0]!.route as any).methods.get, true);

      // GetCollection.
      assert.deepEqual(await executeHandler(routes[0]!.route!.stack[0]!.handle), {
        body: { info: {}, data: [] },
        statusCode: 200,
      });
    });

    it('undefined handlers', async () => {
      const handler = new Handler('/foo/:bar', {});

      const router = handler.generate();
      const routes = router.stack;

      assert.equal(routes.length, 0);
    });

    it('returns a 400 for invalid request payloads', async () => {
      const handler = new Handler('/foo/:bar', {
        createItem: () => Promise.resolve({ fields: {}, path: '/' }),
        updateItem: () => Promise.resolve({ fields: {}, relations: [] }),
      });

      const router = handler.generate();
      const routes = router.stack;

      // CreateItemRequestPayload.
      const createHandler = routes[0]!.route!.stack[0]!.handle;
      await assert.doesNotReject(async () => await executeHandler(createHandler, { body: { foo: 'bar' } }));
      await assert.rejects(async () => await executeHandler(createHandler, { body: null }), BadRequestError);
      await assert.rejects(async () => await executeHandler(createHandler, { body: 'not json' }), BadRequestError);

      // UpdateItemRequestPayload.
      const updateHandler = routes[0]!.route!.stack[0]!.handle;
      await assert.doesNotReject(async () => await executeHandler(updateHandler, { body: { foo: 'bar' } }));
      await assert.rejects(async () => await executeHandler(updateHandler, { body: null }), BadRequestError);
      await assert.rejects(async () => await executeHandler(updateHandler, { body: 'not json' }), BadRequestError);
    });
  });
});