authentik/web/src/pages/generic/FlowShellCard.ts

import { LitElement, html, customElement, property, TemplateResult } from "lit-element";

enum ResponseType {
    redirect = "redirect",
    template = "template",
}

interface Response {
    type: ResponseType;
    to?: string;
    body?: string;
}

@customElement("ak-flow-shell-card")
export class FlowShellCard extends LitElement {
    @property()
    flowBodyUrl = "";

    @property()
    flowBody?: string;

    createRenderRoot(): Element | ShadowRoot {
        return this;
    }

    firstUpdated(): void {
        fetch(this.flowBodyUrl)
            .then((r) => {
                if (r.status === 404) {
                    // Fallback when the flow does not exist, just redirect to the root
                    window.location.pathname = "/";
                } else if (!r.ok) {
                    throw Error(r.statusText);
                }
                return r;
            })
            .then((r) => {
                return r.json();
            })
            .then((r) => {
                this.updateCard(r);
            })
            .catch((e) => {
                // Catch JSON or Update errors
                this.errorMessage(e);
            });
    }

    async updateCard(data: Response): Promise<void> {
        switch (data.type) {
        case ResponseType.redirect:
            window.location.assign(data.to || "");
            break;
        case ResponseType.template:
            this.flowBody = data.body;
            await this.requestUpdate();
            this.checkAutofocus();
            this.loadFormCode();
            this.setFormSubmitHandlers();
            break;
        default:
            console.debug(`authentik/flows: unexpected data type ${data.type}`);
            break;
        }
    }

    loadFormCode(): void {
        this.querySelectorAll("script").forEach((script) => {
            const newScript = document.createElement("script");
            newScript.src = script.src;
            document.head.appendChild(newScript);
        });
    }

    checkAutofocus(): void {
        const autofocusElement = <HTMLElement>this.querySelector("[autofocus]");
        if (autofocusElement !== null) {
            autofocusElement.focus();
        }
    }

    updateFormAction(form: HTMLFormElement): boolean {
        for (let index = 0; index < form.elements.length; index++) {
            const element = <HTMLInputElement>form.elements[index];
            if (element.value === form.action) {
                console.debug(
                    "authentik/flows: Found Form action URL in form elements, not changing form action."
                );
                return false;
            }
        }
        form.action = this.flowBodyUrl;
        console.debug(`authentik/flows: updated form.action ${this.flowBodyUrl}`);
        return true;
    }

    checkAutosubmit(form: HTMLFormElement): void {
        if ("autosubmit" in form.attributes) {
            return form.submit();
        }
    }

    setFormSubmitHandlers(): void {
        this.querySelectorAll("form").forEach((form) => {
            console.debug(`authentik/flows: Checking for autosubmit attribute ${form}`);
            this.checkAutosubmit(form);
            console.debug(`authentik/flows: Setting action for form ${form}`);
            this.updateFormAction(form);
            console.debug(`authentik/flows: Adding handler for form ${form}`);
            form.addEventListener("submit", (e) => {
                e.preventDefault();
                const formData = new FormData(form);
                this.flowBody = undefined;
                fetch(this.flowBodyUrl, {
                    method: "post",
                    body: formData,
                })
                    .then((response) => {
                        return response.json();
                    })
                    .then((data) => {
                        this.updateCard(data);
                    })
                    .catch((e) => {
                        this.errorMessage(e);
                    });
            });
            form.classList.add("ak-flow-wrapped");
        });
    }

    errorMessage(error: string): void {
        this.flowBody = `
            <style>
                .ak-exception {
                    font-family: monospace;
                    overflow-x: scroll;
                }
            </style>
            <header class="pf-c-login__main-header">
                <h1 class="pf-c-title pf-m-3xl">
                    Whoops!
                </h1>
            </header>
            <div class="pf-c-login__main-body">
                <h3>
                    Something went wrong! Please try again later.
                </h3>
                <pre class="ak-exception">${error}</pre>
            </div>`;
    }

    loading(): TemplateResult {
        return html` <div class="pf-c-login__main-body ak-loading">
            <span class="pf-c-spinner" role="progressbar" aria-valuetext="Loading...">
                <span class="pf-c-spinner__clipper"></span>
                <span class="pf-c-spinner__lead-ball"></span>
                <span class="pf-c-spinner__tail-ball"></span>
            </span>
        </div>`;
    }

    render(): TemplateResult {
        if (this.flowBody) {
            return html(<TemplateStringsArray>(<unknown>[this.flowBody]));
        }
        return this.loading();
    }
}