import { jest, describe, it, expect } from '@jest/globals';
import { loadConfigFromElement, defaultConfig } from '../../src/pyconfig';
import { version } from '../../src/version';
import { UserError } from '../../src/exceptions';

// inspired by trump typos
const covfefeConfig = {
    name: 'covfefe',
    interpreters: [
        {
            src: '/demo/covfefe.js',
            name: 'covfefe',
            lang: 'covfefe',
        },
    ],
    wonderful: 'disgrace',
};

const covfefeConfigToml = `
name = "covfefe"

wonderful = "hijacked"

[[interpreters]]
src = "/demo/covfefe.js"
name = "covfefe"
lang = "covfefe"
`;

// ideally, I would like to be able to just do "new HTMLElement" in the tests
// below, but it is not permitted. The easiest work around is to create a fake
// custom element: not that we are not using any specific feature of custom
// elements: the sole purpose to FakeElement is to be able to instantiate them
// in the tests.
class FakeElement extends HTMLElement {
    constructor() {
        super();
    }
}
customElements.define('fake-element', FakeElement);

function make_config_element(attrs) {
    const el = new FakeElement();
    for (const [key, value] of Object.entries(attrs)) {
        el.setAttribute(key, value as string);
    }
    return el;
}

describe('loadConfigFromElement', () => {
    const xhrMockClass = () => ({
        open: jest.fn(),
        send: jest.fn(),
        responseText: JSON.stringify(covfefeConfig),
    });
    // @ts-ignore
    window.XMLHttpRequest = jest.fn().mockImplementation(xhrMockClass);

    it('should load the default config', () => {
        const config = loadConfigFromElement(null);
        expect(config).toBe(defaultConfig);
        expect(config.pyscript.version).toBe(version);
    });

    it('an empty <py-config> should load the default config', () => {
        const el = make_config_element({});
        let config = loadConfigFromElement(el);
        expect(config).toBe(defaultConfig);
        expect(config.pyscript.version).toBe(version);
    });

    it('should load the JSON config from inline', () => {
        const el = make_config_element({ type: 'json' });
        el.innerHTML = JSON.stringify(covfefeConfig);
        const config = loadConfigFromElement(el);
        expect(config.interpreters[0].lang).toBe('covfefe');
        expect(config.pyscript?.time).not.toBeNull();
        // schema_version wasn't present in `inline config` but is still set due to merging with default
        expect(config.schema_version).toBe(1);
    });

    it('should load the JSON config from src attribute', () => {
        const el = make_config_element({ type: 'json', src: '/covfefe.json' });
        const config = loadConfigFromElement(el);
        expect(config.interpreters[0].lang).toBe('covfefe');
        expect(config.pyscript?.time).not.toBeNull();
        // wonderful is an extra key supplied by the user and is unaffected by merging process
        expect(config.wonderful).toBe('disgrace');
        // schema_version wasn't present in `config from src` but is still set due to merging with default
        expect(config.schema_version).toBe(1);
    });

    it('should load the JSON config from both inline and src', () => {
        const el = make_config_element({ type: 'json', src: '/covfefe.json' });
        el.innerHTML = JSON.stringify({ version: '0.2a', wonderful: 'hijacked' });
        const config = loadConfigFromElement(el);
        expect(config.interpreters[0].lang).toBe('covfefe');
        expect(config.pyscript?.time).not.toBeNull();
        // config from src had an extra key "wonderful" with value "disgrace"
        // inline config had the same extra key "wonderful" with value "hijacked"
        // the merge process works for extra keys that clash as well
        // so the final value is "hijacked" since inline takes precedence over src
        expect(config.wonderful).toBe('hijacked');
        // version wasn't present in `config from src` but is still set due to merging with default and inline
        expect(config.version).toBe('0.2a');
    });

    it('should be able to load an inline TOML config', () => {
        // TOML is the default type
        const el = make_config_element({});
        el.innerHTML = covfefeConfigToml;
        const config = loadConfigFromElement(el);
        expect(config.interpreters[0].lang).toBe('covfefe');
        expect(config.pyscript?.time).not.toBeNull();
        // schema_version wasn't present in `inline config` but is still set due to merging with default
        expect(config.schema_version).toBe(1);
        expect(config.wonderful).toBe('hijacked');
    });

    it('should NOT be able to load an inline config in JSON format with type as TOML', () => {
        const el = make_config_element({});
        el.innerHTML = JSON.stringify(covfefeConfig);
        expect(() => loadConfigFromElement(el)).toThrow(
            /config supplied: {.*} is an invalid TOML and cannot be parsed/,
        );
    });

    it('should NOT be able to load an inline config in TOML format with type as JSON', () => {
        const el = make_config_element({ type: 'json' });
        el.innerHTML = covfefeConfigToml;
        expect(() => loadConfigFromElement(el)).toThrow(UserError);
    });

    it('should NOT be able to load an inline TOML config with a JSON config from src with type as toml', () => {
        const el = make_config_element({ src: '/covfefe.json' });
        el.innerHTML = covfefeConfigToml;
        expect(() => loadConfigFromElement(el)).toThrow(
            /config supplied: {.*} is an invalid TOML and cannot be parsed/,
        );
    });

    it('should NOT be able to load an inline TOML config with a JSON config from src with type as json', () => {
        const el = make_config_element({ type: 'json', src: '/covfefe.json' });
        el.innerHTML = covfefeConfigToml;
        expect(() => loadConfigFromElement(el)).toThrow(UserError);
    });

    it('should error out when passing an invalid JSON', () => {
        const el = make_config_element({ type: 'json' });
        el.innerHTML = '[[';
        expect(() => loadConfigFromElement(el)).toThrow(UserError);
    });

    it('should error out when passing an invalid TOML', () => {
        const el = make_config_element({});
        el.innerHTML = '[[';
        expect(() => loadConfigFromElement(el)).toThrow(UserError);
    });

    it('should not escape characters like &', () => {
        const el = make_config_element({ type: 'json' });
        el.innerHTML = JSON.stringify({
            fetch: [{ from: 'https://datausa.io/api/data?drilldowns=Nation&measures=Population' }],
        });
        const config = loadConfigFromElement(el);
        expect(config.fetch[0].from).toBe('https://datausa.io/api/data?drilldowns=Nation&measures=Population');
    });
});