//! The tip control, described.
//!
//! "Support", and behind it an amount, an optional message and a submit that
//! hands the reader to Stripe. It replaces `templates/partials/tip_button.html`,
//! which both public creator pages included.
//!
//! # The disclosure is the vocabulary's now
//!
//! The partial drew a button carrying `data-action="toggleTipForm"` and a form
//! carrying `hidden`, and a function in `actions-pages.js` swapped the class.
//! A region that shows at most one child is what that is
//! ([`Slot::showing_at_most_one`]), and `quasi-webview` writes the control and
//! the program that moves it. Nothing is asked of the server to open it, which
//! is what it always meant.
//!
//! # The token is not a field any more
//!
//! The form carried a hidden `_csrf`. `create_tip_checkout` reads the token
//! header-first and falls back to the field, and a described form is an htmx
//! post, so `frontend/src/core/htmx-glue.ts` attaches the header from the
//! document's `csrf-token` meta. The hidden input was a second copy of a token
//! that rotates mid-session. Same removal the reset link's token got, for the
//! same reason.
//!
//! # And the answer is a redirect
//!
//! `create_tip_checkout` ends at Stripe, so it answers a 303. An htmx request
//! follows that in the browser and swaps whatever came back into the control
//! that sent it, which is the failure `c7b0d3c1` hit on the header's Log Out.
//! The handler answers `HX-Redirect` to an htmx caller for that reason.

use quasi_declare::declare;
use quasi_router::Action;

/// The region the offer sits in, and the disclosure that opens it.
pub const REGION: &str = "tip-offer";

/// The region holding the form itself, which is what the disclosure opens.
const FORM_REGION: &str = "tip-form";

/// What a page needs to know to offer a tip.
pub struct Offer<'a> {
    /// Who is being tipped.
    pub creator_id: &'a str,
    /// Which project the tip is attributed to, on a project page.
    pub project_id: Option<&'a str>,
    /// Whether there is a session. Without one the offer is a link to sign in,
    /// which is what the partial drew: a tip is a charge and a charge needs an
    /// account.
    pub signed_in: bool,
}

declare! {
    /// The offer, as the page carries it.
    ///
    /// `None` from the caller when the creator does not take tips; this returns the
    /// node for when they do.
    #[must_use]
    pub shape control(offer: &Offer<'_>) -> Node;

    given offer.signed_in {
        false -> region REGION as Group {
            act "Support" to get "/login" navigating;
        }
        true -> region REGION as Group {
            showing_at_most_one None;
            region FORM_REGION as Group {
                label "Support";
                form doing checkout(offer) {
                    submit "Send tip";
                    field Number "amount_dollars" "Tip amount" {
                        required;
                        value "1";
                        unit "$";
                        within "1" "9999";
                    }
                    field Textarea "message" "Message (optional)" {
                        placeholder "Add a message (optional)";
                        limited_to 280;
                    }
                }
            }
        }
    }
}

/// Where a tip is taken, and what it is attributed to.
///
/// A supplier rather than a spelled-out action, because the project is carried
/// only on a project page and the form has no way to say "and this value too,
/// sometimes". Amendment 6's `doing` is the remedy the form names for exactly
/// this.
fn checkout(offer: &Offer<'_>) -> Action {
    let action = Action::post(format!("/stripe/checkout/tip/{}", offer.creator_id));
    match offer.project_id {
        Some(project) => action.with("project_id", project),
        None => action,
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use quasi_router::Node;
    use quasi_webview::Webview;

    fn html(node: &Node) -> String {
        use quasi_axum::Serves as _;
        Webview::new().fragment(node)
    }

    /// A reader with no session is offered the way to get one, which is what
    /// the partial drew: a tip is a charge, and a charge needs an account.
    #[test]
    fn a_signed_out_reader_is_sent_to_sign_in() {
        let rendered = html(&control(&Offer {
            creator_id: "c1",
            project_id: None,
            signed_in: false,
        }));
        assert!(rendered.contains("/login"), "{rendered}");
        assert!(!rendered.contains("amount_dollars"), "{rendered}");
    }

    /// The amount, the message and the cap the partial wrote on each.
    #[test]
    fn the_form_keeps_the_limits_the_partial_wrote() {
        let rendered = html(&control(&Offer {
            creator_id: "c1",
            project_id: None,
            signed_in: true,
        }));
        assert!(rendered.contains("name=\"amount_dollars\""), "{rendered}");
        assert!(rendered.contains("min=\"1\""), "{rendered}");
        assert!(rendered.contains("max=\"9999\""), "{rendered}");
        assert!(rendered.contains("maxlength=\"280\""), "{rendered}");
    }

    /// A tip from a project page is attributed to it, which is what the
    /// partial's second hidden field did.
    #[test]
    fn a_tip_from_a_project_page_carries_the_project() {
        let rendered = html(&control(&Offer {
            creator_id: "c1",
            project_id: Some("p9"),
            signed_in: true,
        }));
        assert!(rendered.contains("project_id"), "{rendered}");
        assert!(rendered.contains("p9"), "{rendered}");
    }

    /// The token is the header's now. A hidden input is a second copy of
    /// something that rotates mid-session.
    #[test]
    fn the_form_carries_no_hidden_token() {
        let rendered = html(&control(&Offer {
            creator_id: "c1",
            project_id: None,
            signed_in: true,
        }));
        assert!(!rendered.contains("_csrf"), "{rendered}");
        assert!(!rendered.contains("type=\"hidden\""), "{rendered}");
    }

    /// The disclosure is the region's, so nothing on this page calls a
    /// function in its own JavaScript to open it.
    #[test]
    fn the_offer_opens_without_a_script_of_its_own() {
        let rendered = html(&control(&Offer {
            creator_id: "c1",
            project_id: None,
            signed_in: true,
        }));
        assert!(!rendered.contains("toggleTipForm"), "{rendered}");
        assert!(rendered.contains("data-shows"), "{rendered}");
    }
}