io-msgraph 0.7.0

//! # vCard projection
//!
//! Projects a Microsoft Graph contact onto a vCard 4.0 document
//! ([`MsgraphContact::to_vcard`]), and a vCard back onto a contact
//! ([`MsgraphContact::from_vcard`]).
//!
//! Graph exposes no vCard representation of a contact, its endpoints only
//! speaking the JSON contact resource, so a consumer needing one (an
//! address book client, a sync engine) synthesizes the document of record
//! here. Only fields with a well-defined vCard slot are projected:
//!
//! - Graph-only fields (`fileAs`, `officeLocation`, `assistantName`,
//!   `manager`) are minted as read-only `X-MSGRAPH-*` properties and
//!   consumed on the way back, the server value staying authoritative;
//! - every other vCard line rides a single-value extended property, the
//!   stash ([`MSGRAPH_CONTACT_STASH_ID`]), and is spliced back verbatim on
//!   read. Graph omits extended properties unless expanded, so a read that
//!   should carry the stash passes [`MSGRAPH_CONTACT_STASH_EXPAND`].
//!
//! [`MsgraphContact::from_vcard`] is the full-state projection: every
//! managed field is Set when the vCard carries it and Null when it does
//! not, while Graph-only fields stay Unset and survive updates untouched.
//! [`MsgraphContact::create_from_vcard`] shapes a create body and
//! [`MsgraphContact::update_from_vcard`] an update body, both stripping the
//! gratuitous nulls the Outlook backend rejects with HTTP 500.

use core::{fmt, str::FromStr};

use alloc::{
    borrow::Cow,
    boxed::Box,
    format,
    string::{String, ToString},
    vec,
    vec::Vec,
};

use crate::v1::{
    field::MsgraphField,
    rest::users::{
        contacts::{MsgraphContact, MsgraphPhysicalAddress, MsgraphSingleValueExtendedProperty},
        messages::MsgraphEmailAddress,
    },
};
use serde_json::{from_value, to_value};
use vcard::{
    param::VcardParam,
    prop::{
        VcardProp, VcardPropKind, VcardPropName, adr::ADR, categories::CATEGORIES, email::EMAIL,
        r#fn::FN, impp::IMPP, n::N, nickname::NICKNAME, note::NOTE, org::ORG, related::RELATED,
        role::ROLE, tel::TEL, title::TITLE, url::URL,
    },
    tree::{cst::VcardCst, error::VcardParseError, line::VcardLine, prop::lens::VcardPropLens},
    value::{
        VcardValue,
        adr::VcardAdr,
        datetime::VcardDateAndOrTime,
        n::VcardN,
        org::VcardOrg,
        text::{VcardText, VcardTextList},
        uri::VcardUri,
    },
};

/// Extended-property id under which the vCard remainder is stashed on the
/// Graph contact, a fixed app GUID plus a name (the String MAPI form).
///
/// It rides inline in create and update bodies. The name predates this
/// crate (Cardamum wrote it first) and is kept so contacts stashed then
/// still read back.
pub const MSGRAPH_CONTACT_STASH_ID: &str =
    "String {c8e5e5cf-3f6c-4f0a-9d4e-52f1e7b2a9d3} Name cardamum-vcard";

/// The `$expand` clause reading the stash back with a contact, which Graph
/// omits otherwise.
pub const MSGRAPH_CONTACT_STASH_EXPAND: &str = "singleValueExtendedProperties($filter=id eq \
     'String {c8e5e5cf-3f6c-4f0a-9d4e-52f1e7b2a9d3} Name cardamum-vcard')";

/// Longest raw property line stashed server-side.
///
/// A longer line, a base64 PHOTO blob essentially, stays in the local
/// document of record rather than risking the whole write against an
/// undocumented size limit.
const MAX_STASH_LINE: usize = 8 * 1024;

/// Property names minted by [`to_vcard`] from the Graph-only contact
/// fields.
///
/// [`to_contact`] consumes them, the server value being authoritative: the
/// fields stay Unset, out of every body.
const MINTED_PROPS: &[&str] = &[
    "X-MSGRAPH-FILE-AS",
    "X-MSGRAPH-OFFICE-LOCATION",
    "X-MSGRAPH-ASSISTANT",
    "X-MSGRAPH-MANAGER",
];

impl MsgraphContact {
    /// Projects an io-msgraph contact onto a fresh vCard 4.0 document.
    ///
    /// The UID is the one the stash carries ([`stashed_uid`]), else one minted
    /// from the Graph id for a contact Graph created itself. The phone and
    /// address slots become typed TEL and ADR properties (business work, home
    /// home, mobile cell), and spouse and children become RELATED names, their
    /// types being standard in vCard 4.0.
    ///
    /// [`stashed_uid`]: Self::stashed_uid
    pub fn to_vcard(&self) -> String {
        let contact = self;
        let mut card = VcardCst::v4();

        let id = contact.id.trim();
        if contact.stashed_uid().is_none() && !id.is_empty() {
            card.push(VcardProp::text(VcardPropKind::Uid, vec![], id));
        }

        card.push(VcardProp::text(
            VcardPropKind::Fn,
            vec![],
            display_name(contact),
        ));

        // NOTE: the Graph title is the honorific (Dr., Mrs.), hence the N
        // prefix slot; the job title maps to TITLE below.
        let n = VcardN {
            family: component(&contact.surname),
            given: component(&contact.given_name),
            additional: component(&contact.middle_name),
            prefixes: component(&contact.title),
            suffixes: Vec::new(),
        };

        let empty = n.family.is_empty()
            && n.given.is_empty()
            && n.additional.is_empty()
            && n.prefixes.is_empty();
        if !empty {
            card.push(VcardProp {
                group: None,
                name: VcardPropName::Kind(VcardPropKind::N),
                params: vec![],
                value: VcardValue::N(n),
            });
        }

        if let Some(nick) = opt(&contact.nick_name) {
            card.push(VcardProp {
                group: None,
                name: VcardPropName::Kind(VcardPropKind::Nickname),
                params: vec![],
                value: VcardValue::TextList(VcardTextList(vec![Cow::Owned(nick.to_string())])),
            });
        }

        for email in list(&contact.email_addresses) {
            if let Some(address) = email.address.as_deref() {
                let address = address.trim();
                if !address.is_empty() {
                    card.push(VcardProp::text(VcardPropKind::Email, vec![], address));
                }
            }
        }

        for im in list(&contact.im_addresses) {
            let im = im.trim();
            if !im.is_empty() {
                card.push(VcardProp {
                    group: None,
                    name: VcardPropName::Kind(VcardPropKind::Impp),
                    params: vec![],
                    value: VcardValue::Uri(VcardUri(Cow::Owned(im.to_string()))),
                });
            }
        }

        for phone in list(&contact.business_phones) {
            let phone = phone.trim();
            if !phone.is_empty() {
                card.push(VcardProp::text(
                    VcardPropKind::Tel,
                    vec![type_param("work")],
                    phone,
                ));
            }
        }
        for phone in list(&contact.home_phones) {
            let phone = phone.trim();
            if !phone.is_empty() {
                card.push(VcardProp::text(
                    VcardPropKind::Tel,
                    vec![type_param("home")],
                    phone,
                ));
            }
        }
        if let Some(phone) = opt(&contact.mobile_phone) {
            card.push(VcardProp::text(
                VcardPropKind::Tel,
                vec![type_param("cell")],
                phone,
            ));
        }

        if let Some(prop) = adr_prop(contact.home_address.as_option(), Some("home")) {
            card.push(prop);
        }
        if let Some(prop) = adr_prop(contact.business_address.as_option(), Some("work")) {
            card.push(prop);
        }
        if let Some(prop) = adr_prop(contact.other_address.as_option(), None) {
            card.push(prop);
        }

        let company = opt(&contact.company_name);
        let department = opt(&contact.department);
        if company.is_some() || department.is_some() {
            let mut components: Vec<Cow<'static, str>> =
                vec![Cow::Owned(company.unwrap_or_default().to_string())];
            if let Some(department) = department {
                components.push(Cow::Owned(department.to_string()));
            }
            card.push(VcardProp {
                group: None,
                name: VcardPropName::Kind(VcardPropKind::Org),
                params: vec![],
                value: VcardValue::Org(VcardOrg(components)),
            });
        }

        if let Some(title) = opt(&contact.job_title) {
            card.push(VcardProp::text(VcardPropKind::Title, vec![], title));
        }
        if let Some(role) = opt(&contact.profession) {
            card.push(VcardProp::text(VcardPropKind::Role, vec![], role));
        }
        if let Some(page) = opt(&contact.business_home_page) {
            card.push(VcardProp {
                group: None,
                name: VcardPropName::Kind(VcardPropKind::Url),
                params: vec![],
                value: VcardValue::Uri(VcardUri(Cow::Owned(page.to_string()))),
            });
        }

        // NOTE: Graph serves the birthday as an ISO 8601 date-time
        // (1983-04-01T00:00:00Z); only its date part has a vCard slot.
        if let Some(birthday) = opt(&contact.birthday) {
            let date = birthday.split('T').next().unwrap_or(birthday);
            if let Some(date) = VcardDateAndOrTime::from(date).full_date() {
                card.push(VcardProp {
                    group: None,
                    name: VcardPropName::Kind(VcardPropKind::Bday),
                    params: vec![],
                    value: VcardValue::DateAndOrTime(VcardDateAndOrTime(Cow::Owned(date))),
                });
            }
        }

        if let Some(notes) = opt(&contact.personal_notes) {
            card.push(VcardProp::text(VcardPropKind::Note, vec![], notes));
        }

        let categories: Vec<Cow<'static, str>> = list(&contact.categories)
            .iter()
            .map(|category| category.trim())
            .filter(|category| !category.is_empty())
            .map(|category| Cow::Owned(category.to_string()))
            .collect();
        if !categories.is_empty() {
            card.push(VcardProp {
                group: None,
                name: VcardPropName::Kind(VcardPropKind::Categories),
                params: vec![],
                value: VcardValue::TextList(VcardTextList(categories)),
            });
        }

        if let Some(spouse) = opt(&contact.spouse_name) {
            card.push(related_prop("spouse", spouse));
        }
        for child in list(&contact.children) {
            let child = child.trim();
            if !child.is_empty() {
                card.push(related_prop("child", child));
            }
        }

        // NOTE: Graph-only fields ride the vCard as read-only X-MSGRAPH-*
        // vendor properties, and the stashed remainder restores verbatim.
        let minted = [
            ("X-MSGRAPH-FILE-AS", opt(&contact.file_as)),
            ("X-MSGRAPH-OFFICE-LOCATION", opt(&contact.office_location)),
            ("X-MSGRAPH-ASSISTANT", opt(&contact.assistant_name)),
            ("X-MSGRAPH-MANAGER", opt(&contact.manager)),
        ];
        for (name, value) in minted {
            if let Some(value) = value {
                card.push(VcardProp::text(name, vec![], value));
            }
        }

        let stash = stash_lines(contact);
        for line in &stash {
            // NOTE: a line that no longer tokenises restores nothing rather
            // than corrupting the card.
            let _ = card.push_raw(line);
        }

        String::from_utf8_lossy(&card.to_bytes()).into_owned()
    }

    /// Projects a vCard onto an io-msgraph contact, in full state: each managed
    /// field is Set from the vCard or Null when absent (collections clear
    /// through an empty Set), while unmanaged Graph fields stay Unset.
    ///
    /// Graph keeps fixed slots even behind its collection-typed properties, so
    /// the first matching vCard property fills a slot and the extras fall to
    /// the stash rather than into another slot. Graph has no UID slot, so the
    /// UID rides the stash too, which is what keeps a contact's identity
    /// across a sync with another source.
    pub fn from_vcard(vcard: &str) -> Result<Self, MsgraphContactVcardError> {
        let card = VcardCst::parse(vcard).map_err(MsgraphContactVcardError::Parse)?;
        let version = card.version();

        let mut display_name = None;
        let mut surname = None;
        let mut given_name = None;
        let mut middle_name = None;
        let mut title = None;
        let mut nick_name = None;
        let mut emails = Vec::new();
        let mut ims = Vec::new();
        let mut business_phones = Vec::new();
        let mut home_phones = Vec::new();
        let mut mobile_phone = None;
        let mut home_address = None;
        let mut business_address = None;
        let mut other_address = None;
        let mut company_name = None;
        let mut department = None;
        let mut job_title = None;
        let mut profession = None;
        let mut business_home_page = None;
        let mut birthday = None;
        let mut spouse_name = None;
        let mut children = Vec::new();
        let mut categories = Vec::new();
        let mut notes = Vec::new();
        let mut stash = Vec::new();
        let mut name_seen = false;

        // NOTE: Outlook stores fixed slots behind the Graph collections:
        // three email addresses, three IM addresses, two business and two
        // home phones (Graph rejects bodies overflowing a slot set). The
        // first properties win, and the extras land in the stash remainder
        // like every other line that does not project, so they survive on
        // the server and restore on read (cairn/spec/projection.md).
        for line in &card.props {
            let consumed = match VcardPropKind::from_str(line.name.get()) {
                // NOTE: the VERSION line is structural and the minted
                // X-MSGRAPH-* properties are read-only projections;
                // neither belongs to the remainder.
                Err(_) => {
                    let raw_name = line.name.get();
                    raw_name.eq_ignore_ascii_case("VERSION")
                        || MINTED_PROPS
                            .iter()
                            .any(|prop| raw_name.eq_ignore_ascii_case(prop))
                }
                Ok(VcardPropKind::Fn) => {
                    let name = FN::decode(line, version);
                    set_first(&mut display_name, &name.0)
                }
                Ok(VcardPropKind::N) => {
                    if !name_seen {
                        name_seen = true;
                        let n = N::decode(line, version);
                        set_first(&mut surname, n.family.join(" "));
                        set_first(&mut given_name, n.given.join(" "));
                        set_first(&mut middle_name, n.additional.join(" "));
                        set_first(&mut title, n.prefixes.join(" "));
                        true
                    } else {
                        false
                    }
                }
                Ok(VcardPropKind::Nickname) => {
                    let all = NICKNAME::decode(line, version);
                    match all.0.first() {
                        Some(nick) => set_first(&mut nick_name, nick),
                        None => false,
                    }
                }
                Ok(VcardPropKind::Email) => {
                    let email = EMAIL::decode(line, version);
                    let address = email.0.trim();
                    if emails.len() < 3 && !address.is_empty() {
                        emails.push(MsgraphEmailAddress {
                            name: None,
                            address: Some(address.to_string()),
                        });
                        true
                    } else {
                        false
                    }
                }
                Ok(VcardPropKind::Impp) => {
                    let impp = IMPP::decode(line, version);
                    let address = impp.0.trim();
                    if ims.len() < 3 && !address.is_empty() {
                        ims.push(address.to_string());
                        true
                    } else {
                        false
                    }
                }
                Ok(VcardPropKind::Tel) => {
                    let tel = TEL::decode(line, version);
                    let number = tel.0.trim();
                    if number.is_empty() {
                        false
                    } else {
                        let types = type_values(line);
                        if types.iter().any(|t| t == "cell") {
                            // NOTE: one mobile slot; further cell TELs are
                            // stashed rather than misfiled as business
                            // phones.
                            if mobile_phone.is_none() {
                                mobile_phone = Some(number.to_string());
                                true
                            } else {
                                false
                            }
                        } else if types.iter().any(|t| t == "home") {
                            if home_phones.len() < 2 {
                                home_phones.push(number.to_string());
                                true
                            } else {
                                false
                            }
                        } else if business_phones.len() < 2 {
                            business_phones.push(number.to_string());
                            true
                        } else {
                            false
                        }
                    }
                }
                Ok(VcardPropKind::Adr) => {
                    let adr = ADR::decode(line, version);

                    // NOTE: Graph's street is one multiline field; the po
                    // box and extended components fold into it so nothing
                    // is lost.
                    let street: Vec<&str> = adr
                        .po_box
                        .iter()
                        .chain(&adr.extended)
                        .chain(&adr.street)
                        .map(|component| component.as_ref().trim())
                        .filter(|component| !component.is_empty())
                        .collect();

                    let address = MsgraphPhysicalAddress {
                        street: (!street.is_empty()).then(|| street.join("\n")),
                        city: joined(&adr.locality),
                        state: joined(&adr.region),
                        country_or_region: joined(&adr.country),
                        postal_code: joined(&adr.postal_code),
                    };

                    let empty = address.street.is_none()
                        && address.city.is_none()
                        && address.state.is_none()
                        && address.country_or_region.is_none()
                        && address.postal_code.is_none();
                    if empty {
                        false
                    } else {
                        let types = type_values(line);
                        let slot = if types.iter().any(|t| t == "home") {
                            &mut home_address
                        } else if types.iter().any(|t| t == "work") {
                            &mut business_address
                        } else {
                            &mut other_address
                        };
                        if slot.is_none() {
                            *slot = Some(address);
                            true
                        } else {
                            false
                        }
                    }
                }
                Ok(VcardPropKind::Org) => {
                    if company_name.is_none() && department.is_none() {
                        let org = ORG::decode(line, version);
                        let mut components = org.0.iter().map(|component| component.as_ref());
                        let company = components.next().unwrap_or_default();
                        let rest = components.collect::<Vec<_>>().join(" ");
                        set_first(&mut company_name, company);
                        set_first(&mut department, rest);
                        true
                    } else {
                        false
                    }
                }
                Ok(VcardPropKind::Title) => {
                    let value = TITLE::decode(line, version);
                    set_first(&mut job_title, &value.0)
                }
                Ok(VcardPropKind::Role) => {
                    let role = ROLE::decode(line, version);
                    set_first(&mut profession, &role.0)
                }
                Ok(VcardPropKind::Url) => {
                    let url = URL::decode(line, version);
                    set_first(&mut business_home_page, &url.0)
                }
                Ok(VcardPropKind::Bday) => {
                    // NOTE: a partial (year-less) birthday has no Graph
                    // date it round-trips through; it lands in the stash.
                    if birthday.is_none()
                        && let Some(date) =
                            VcardDateAndOrTime::from(line.raw_value_str()).full_date()
                    {
                        birthday = Some(format!("{date}T00:00:00Z"));
                        true
                    } else {
                        false
                    }
                }
                Ok(VcardPropKind::Note) => {
                    let note = NOTE::decode(line, version);
                    let note = note.0.trim();
                    if !note.is_empty() {
                        notes.push(note.to_string());
                        true
                    } else {
                        false
                    }
                }
                Ok(VcardPropKind::Categories) => {
                    let all = CATEGORIES::decode(line, version);
                    let mut pushed = false;
                    for category in &all.0 {
                        let category = category.trim();
                        if !category.is_empty() {
                            categories.push(category.to_string());
                            pushed = true;
                        }
                    }
                    pushed
                }
                Ok(VcardPropKind::Related) => {
                    // NOTE: only free-form spouse and child names
                    // (VALUE=text) project; other types and URI RELATED
                    // lines land in the stash.
                    let text = line.params.iter().any(|param| {
                        param.name.get().eq_ignore_ascii_case("VALUE")
                            && param
                                .values
                                .iter()
                                .any(|value| value.get().eq_ignore_ascii_case("text"))
                    });
                    if text {
                        let related = RELATED::decode(line, version);
                        let types = type_values(line);
                        if types.iter().any(|t| t == "spouse") {
                            set_first(&mut spouse_name, &related.0)
                        } else if types.iter().any(|t| t == "child") {
                            let child = related.0.trim();
                            if !child.is_empty() {
                                children.push(child.to_string());
                                true
                            } else {
                                false
                            }
                        } else {
                            false
                        }
                    } else {
                        false
                    }
                }
                Ok(_) => false,
            };

            if !consumed {
                let raw = line.to_string();
                let raw = raw.trim_end().to_string();
                if raw.len() <= MAX_STASH_LINE {
                    stash.push(raw);
                }
            }
        }

        Ok(MsgraphContact {
            display_name: MsgraphField::set_or_null(display_name),
            given_name: MsgraphField::set_or_null(given_name),
            middle_name: MsgraphField::set_or_null(middle_name),
            surname: MsgraphField::set_or_null(surname),
            nick_name: MsgraphField::set_or_null(nick_name),
            title: MsgraphField::set_or_null(title),
            email_addresses: MsgraphField::Set(emails),
            im_addresses: MsgraphField::Set(ims),
            business_phones: MsgraphField::Set(business_phones),
            home_phones: MsgraphField::Set(home_phones),
            mobile_phone: MsgraphField::set_or_null(mobile_phone),
            home_address: MsgraphField::set_or_null(home_address),
            business_address: MsgraphField::set_or_null(business_address),
            other_address: MsgraphField::set_or_null(other_address),
            job_title: MsgraphField::set_or_null(job_title),
            company_name: MsgraphField::set_or_null(company_name),
            department: MsgraphField::set_or_null(department),
            profession: MsgraphField::set_or_null(profession),
            business_home_page: MsgraphField::set_or_null(business_home_page),
            birthday: MsgraphField::set_or_null(birthday),
            spouse_name: MsgraphField::set_or_null(spouse_name),
            children: MsgraphField::Set(children),
            personal_notes: MsgraphField::set_or_null(
                (!notes.is_empty()).then(|| notes.join("\n")),
            ),
            categories: MsgraphField::Set(categories),
            // NOTE: the stash entry is always Set (empty value when the
            // card has no remainder) so the delta projection can tell a
            // cleared stash from an unchanged one.
            single_value_extended_properties: MsgraphField::Set(vec![
                MsgraphSingleValueExtendedProperty {
                    id: MSGRAPH_CONTACT_STASH_ID.to_string(),
                    value: stash.join("\n"),
                },
            ]),
            ..Default::default()
        })
    }

    /// Projects a vCard onto an update body: the fields differing from the base
    /// vCard (the state last synced with the server), the unchanged ones
    /// turning Unset and staying out of the PATCH.
    ///
    /// The Outlook backend rejects the gratuitous nulls of a full-state body
    /// with an internal server error (HTTP 500), so a Null survives only when
    /// the edit cleared a field the base carried (collections clear through an
    /// explicit empty Set instead).
    pub fn update_from_vcard(
        vcard: &str,
        base_vcard: &str,
    ) -> Result<Self, MsgraphContactVcardError> {
        let mut contact = Self::from_vcard(vcard)?;
        let base = Self::from_vcard(base_vcard)?;

        macro_rules! unset_unchanged {
        ($($field:ident),* $(,)?) => {$(
            if contact.$field == base.$field {
                contact.$field = MsgraphField::Unset;
            }
        )*};
    }

        unset_unchanged!(
            display_name,
            given_name,
            middle_name,
            surname,
            nick_name,
            title,
            email_addresses,
            im_addresses,
            business_phones,
            home_phones,
            mobile_phone,
            home_address,
            business_address,
            other_address,
            job_title,
            company_name,
            department,
            profession,
            business_home_page,
            birthday,
            spouse_name,
            children,
            personal_notes,
            categories,
            single_value_extended_properties,
        );

        Ok(contact)
    }

    /// Projects a vCard onto a create body: the full-state projection minus the
    /// explicit nulls and empty collections.
    ///
    /// They are no-ops on a fresh resource, and the Outlook backend rejects null
    /// complex properties on POST with an internal server error (HTTP 500).
    pub fn create_from_vcard(vcard: &str) -> Result<Self, MsgraphContactVcardError> {
        let mut contact = Self::from_vcard(vcard)?;

        // NOTE: an empty stash entry is a no-op on a fresh resource.
        if stash_lines(&contact).is_empty() {
            contact.single_value_extended_properties = MsgraphField::Unset;
        }

        let mut body = to_value(&contact).map_err(MsgraphContactVcardError::Json)?;
        if let Some(object) = body.as_object_mut() {
            object.retain(|_, value| {
                !value.is_null() && value.as_array().is_none_or(|array| !array.is_empty())
            });
        }

        from_value(body).map_err(MsgraphContactVcardError::Json)
    }
}

/// A vCard that cannot become a Graph contact body.
#[derive(Debug)]
pub enum MsgraphContactVcardError {
    /// The vCard does not parse.
    Parse(VcardParseError),
    /// The projected contact does not reshape through JSON.
    Json(serde_json::Error),
}

impl fmt::Display for MsgraphContactVcardError {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            Self::Parse(err) => write!(f, "Invalid vCard: {err}"),
            Self::Json(err) => write!(f, "Cannot shape the Graph contact body: {err}"),
        }
    }
}

impl core::error::Error for MsgraphContactVcardError {}

/// The contact's display name, composed from the name parts when
/// blank, with the filing name as a last resort.
fn display_name(contact: &MsgraphContact) -> String {
    if let Some(name) = opt(&contact.display_name) {
        return name.to_string();
    }

    let composed: Vec<&str> = [&contact.given_name, &contact.middle_name, &contact.surname]
        .into_iter()
        .filter_map(opt)
        .collect();
    if !composed.is_empty() {
        return composed.join(" ");
    }

    opt(&contact.file_as).unwrap_or_default().to_string()
}

/// An ADR property from a Graph physical address, None when every component
/// is empty.
///
/// Graph's street is one multiline field, so each of its lines becomes a
/// vCard street component.
fn adr_prop(
    address: Option<&MsgraphPhysicalAddress>,
    r#type: Option<&'static str>,
) -> Option<VcardProp<'static>> {
    let address = address?;

    let street = address.street.as_deref().unwrap_or("");
    let value = VcardAdr {
        po_box: Vec::new(),
        extended: Vec::new(),
        street: street
            .split('\n')
            .map(str::trim)
            .filter(|line| !line.is_empty())
            .map(|line| Cow::Owned(line.to_string()))
            .collect(),
        locality: option_component(&address.city),
        region: option_component(&address.state),
        postal_code: option_component(&address.postal_code),
        country: option_component(&address.country_or_region),
        ..Default::default()
    };

    let empty = value.street.is_empty()
        && value.locality.is_empty()
        && value.region.is_empty()
        && value.postal_code.is_empty()
        && value.country.is_empty();
    if empty {
        return None;
    }

    Some(VcardProp {
        group: None,
        name: VcardPropName::Kind(VcardPropKind::Adr),
        params: r#type.map(type_param).into_iter().collect(),
        value: VcardValue::Adr(Box::new(value)),
    })
}

/// A RELATED name property (spouse, child): free-form text, hence the
/// explicit VALUE=text (RELATED defaults to a URI).
fn related_prop(r#type: &'static str, name: &str) -> VcardProp<'static> {
    VcardProp {
        group: None,
        name: VcardPropName::Kind(VcardPropKind::Related),
        params: vec![type_param(r#type), VcardParam::Value(Cow::Borrowed("text"))],
        value: VcardValue::Text(VcardText(Cow::Owned(name.to_string()))),
    }
}

/// A single-value TYPE parameter.
fn type_param(value: &'static str) -> VcardParam<'static> {
    VcardParam::Type(vec![Cow::Borrowed(value)])
}

/// The trimmed field, None when unset, null or blank.
fn opt(field: &MsgraphField<String>) -> Option<&str> {
    let value = field.as_deref()?.trim();
    if value.is_empty() { None } else { Some(value) }
}

/// The collection items, empty when the field is unset or null.
fn list<T>(field: &MsgraphField<Vec<T>>) -> &[T] {
    field.as_option().map(Vec::as_slice).unwrap_or(&[])
}

/// A structured-value component holding the trimmed field, or empty.
fn component(field: &MsgraphField<String>) -> Vec<Cow<'static, str>> {
    match opt(field) {
        Some(value) => vec![Cow::Owned(value.to_string())],
        None => Vec::new(),
    }
}

/// Like [`component`], for the plain options of a physical address.
fn option_component(value: &Option<String>) -> Vec<Cow<'static, str>> {
    let value = value.as_deref().unwrap_or("").trim();
    if value.is_empty() {
        Vec::new()
    } else {
        vec![Cow::Owned(value.to_string())]
    }
}

/// Fills a single-instance Graph field, first non-empty value wins;
/// true when this value took the slot.
fn set_first(slot: &mut Option<String>, value: impl AsRef<str>) -> bool {
    let value = value.as_ref().trim();
    if slot.is_none() && !value.is_empty() {
        *slot = Some(value.to_string());
        true
    } else {
        false
    }
}

impl MsgraphContact {
    /// The vCard UID the stash carries, `None` for a contact no vCard was
    /// ever written to, Graph having no UID slot of its own.
    ///
    /// A sync engine checks it after a write: a server that dropped the
    /// stash would hand the contact back with an identity minted from its
    /// Graph id rather than the UID it was written under.
    pub fn stashed_uid(&self) -> Option<String> {
        stash_lines(self).iter().find_map(|line| {
            let mut bytes = line.clone();
            bytes.push_str("\r\n");
            let (line, _) = VcardLine::take(bytes.as_bytes()).ok()?;
            line.bare_name()
                .eq_ignore_ascii_case("UID")
                .then(|| line.raw_value_str().trim().to_string())
                .filter(|uid| !uid.is_empty())
        })
    }
}

/// The stashed vCard remainder lines behind the contact's cardamum
/// extended property (matched by name: Graph may normalize the GUID
/// spelling in responses).
fn stash_lines(contact: &MsgraphContact) -> Vec<String> {
    contact
        .single_value_extended_properties
        .as_option()
        .map(Vec::as_slice)
        .unwrap_or(&[])
        .iter()
        .filter(|prop| prop.id.to_ascii_lowercase().contains("cardamum-vcard"))
        .flat_map(|prop| prop.value.split('\n'))
        .filter(|line| !line.is_empty())
        .map(str::to_string)
        .collect()
}

/// The structured-value components joined into one Graph field, None
/// when nothing remains.
fn joined(components: &[Cow<'_, str>]) -> Option<String> {
    let joined = components
        .iter()
        .map(|component| component.as_ref().trim())
        .filter(|component| !component.is_empty())
        .collect::<Vec<_>>()
        .join(" ");
    if joined.is_empty() {
        None
    } else {
        Some(joined)
    }
}

/// Collects every TYPE parameter value, lowercased.
fn type_values(line: &VcardLine) -> Vec<String> {
    let mut types = Vec::new();
    for param in &line.params {
        if param.name.get().eq_ignore_ascii_case("TYPE") {
            types.extend(
                param
                    .values
                    .iter()
                    .map(|value| value.get().to_ascii_lowercase()),
            );
        }
    }
    types
}

#[cfg(test)]
mod tests {
    use super::*;

    /// A contact filling every field the projection manages.
    fn full_contact() -> MsgraphContact {
        MsgraphContact {
            display_name: MsgraphField::Set("Jane Doe".into()),
            given_name: MsgraphField::Set("Jane".into()),
            middle_name: MsgraphField::Set("Q.".into()),
            surname: MsgraphField::Set("Doe".into()),
            title: MsgraphField::Set("Dr.".into()),
            nick_name: MsgraphField::Set("Janie".into()),
            email_addresses: MsgraphField::Set(vec![MsgraphEmailAddress {
                name: None,
                address: Some("jane@doe.org".into()),
            }]),
            im_addresses: MsgraphField::Set(vec!["xmpp:jane@doe.org".into()]),
            business_phones: MsgraphField::Set(vec!["+331111".into()]),
            home_phones: MsgraphField::Set(vec!["+332222".into()]),
            mobile_phone: MsgraphField::Set("+333333".into()),
            home_address: MsgraphField::Set(MsgraphPhysicalAddress {
                street: Some("12 Main St".into()),
                city: Some("Paris".into()),
                state: Some("IDF".into()),
                country_or_region: Some("France".into()),
                postal_code: Some("75000".into()),
            }),
            business_address: MsgraphField::Set(MsgraphPhysicalAddress {
                street: Some("1 Work Way".into()),
                city: Some("Lyon".into()),
                state: None,
                country_or_region: None,
                postal_code: None,
            }),
            other_address: MsgraphField::Set(MsgraphPhysicalAddress {
                street: Some("3 Other Rd".into()),
                city: None,
                state: None,
                country_or_region: None,
                postal_code: None,
            }),
            company_name: MsgraphField::Set("ACME".into()),
            department: MsgraphField::Set("R&D".into()),
            job_title: MsgraphField::Set("Boss".into()),
            profession: MsgraphField::Set("Engineer".into()),
            business_home_page: MsgraphField::Set("https://doe.org".into()),
            birthday: MsgraphField::Set("1983-04-01T00:00:00Z".into()),
            spouse_name: MsgraphField::Set("John Doe".into()),
            children: MsgraphField::Set(vec!["Jimmy".into()]),
            personal_notes: MsgraphField::Set("a note".into()),
            categories: MsgraphField::Set(vec!["friends".into(), "band".into()]),
            ..Default::default()
        }
    }

    #[test]
    fn to_vcard_projects_every_mapped_field() {
        let mut contact = full_contact();
        contact.id = "AAMkAGI2".into();

        let vcard = (contact).to_vcard();
        assert!(vcard.contains("VERSION:4.0\r\n"));
        assert!(vcard.contains("UID:AAMkAGI2\r\n"));
        assert!(vcard.contains("FN:Jane Doe\r\n"));
        assert!(vcard.contains("N:Doe;Jane;Q.;Dr.;\r\n"));
        assert!(vcard.contains("NICKNAME:Janie\r\n"));
        assert!(vcard.contains("EMAIL:jane@doe.org\r\n"));
        assert!(vcard.contains("IMPP:xmpp:jane@doe.org\r\n"));
        assert!(vcard.contains("TEL;TYPE=work:+331111\r\n"));
        assert!(vcard.contains("TEL;TYPE=home:+332222\r\n"));
        assert!(vcard.contains("TEL;TYPE=cell:+333333\r\n"));
        assert!(vcard.contains("ADR;TYPE=home:;;12 Main St;Paris;IDF;75000;France\r\n"));
        assert!(vcard.contains("ADR;TYPE=work:;;1 Work Way;Lyon;;;\r\n"));
        assert!(vcard.contains("ADR:;;3 Other Rd;;;;\r\n"));
        assert!(vcard.contains("ORG:ACME;R&D\r\n"));
        assert!(vcard.contains("TITLE:Boss\r\n"));
        assert!(vcard.contains("ROLE:Engineer\r\n"));
        assert!(vcard.contains("URL:https://doe.org\r\n"));
        assert!(vcard.contains("BDAY:1983-04-01\r\n"));
        assert!(vcard.contains("NOTE:a note\r\n"));
        assert!(vcard.contains("CATEGORIES:friends,band\r\n"));
        assert!(vcard.contains("RELATED;TYPE=spouse;VALUE=text:John Doe\r\n"));
        assert!(vcard.contains("RELATED;TYPE=child;VALUE=text:Jimmy\r\n"));
    }

    #[test]
    fn to_vcard_composes_fn_from_name_parts() {
        let contact = MsgraphContact {
            given_name: MsgraphField::Set("Jane".into()),
            surname: MsgraphField::Set("Doe".into()),
            ..Default::default()
        };
        assert!((contact).to_vcard().contains("FN:Jane Doe\r\n"));
    }

    #[test]
    fn from_vcard_reads_managed_props() {
        let vcard = "BEGIN:VCARD\r\nVERSION:4.0\r\nUID:abc\r\nFN:Jane Doe\r\n\
            N:Doe;Jane;Q.;Dr.;\r\nNICKNAME:Janie,JJ\r\nEMAIL:jane@doe.org\r\n\
            IMPP:xmpp:jane@doe.org\r\nTEL;TYPE=cell:+333333\r\n\
            TEL;TYPE=home,voice:+332222\r\nTEL:+331111\r\n\
            ADR;TYPE=home:;;12 Main St;Paris;IDF;75000;France\r\nORG:ACME;R&D\r\n\
            TITLE:Boss\r\nROLE:Engineer\r\nURL:https://doe.org\r\nBDAY:1983-04-01\r\n\
            NOTE:a note\r\nCATEGORIES:friends,band\r\n\
            RELATED;TYPE=spouse;VALUE=text:John Doe\r\n\
            RELATED;TYPE=child;VALUE=text:Jimmy\r\nEND:VCARD\r\n";

        let contact = MsgraphContact::from_vcard(vcard).unwrap();
        assert_eq!(contact.id, "");
        assert_eq!(contact.display_name.as_deref(), Some("Jane Doe"));
        assert_eq!(contact.surname.as_deref(), Some("Doe"));
        assert_eq!(contact.given_name.as_deref(), Some("Jane"));
        assert_eq!(contact.middle_name.as_deref(), Some("Q."));
        assert_eq!(contact.title.as_deref(), Some("Dr."));
        assert_eq!(contact.nick_name.as_deref(), Some("Janie"));
        let emails = contact.email_addresses.as_option().unwrap();
        assert_eq!(emails[0].address.as_deref(), Some("jane@doe.org"));
        assert_eq!(
            contact.im_addresses.as_option().unwrap(),
            &vec!["xmpp:jane@doe.org".to_string()]
        );
        assert_eq!(contact.mobile_phone.as_deref(), Some("+333333"));
        assert_eq!(
            contact.home_phones.as_option().unwrap(),
            &vec!["+332222".to_string()]
        );
        assert_eq!(
            contact.business_phones.as_option().unwrap(),
            &vec!["+331111".to_string()]
        );
        let home = contact.home_address.as_option().unwrap();
        assert_eq!(home.street.as_deref(), Some("12 Main St"));
        assert_eq!(home.city.as_deref(), Some("Paris"));
        assert_eq!(home.state.as_deref(), Some("IDF"));
        assert_eq!(home.postal_code.as_deref(), Some("75000"));
        assert_eq!(home.country_or_region.as_deref(), Some("France"));
        assert_eq!(contact.company_name.as_deref(), Some("ACME"));
        assert_eq!(contact.department.as_deref(), Some("R&D"));
        assert_eq!(contact.job_title.as_deref(), Some("Boss"));
        assert_eq!(contact.profession.as_deref(), Some("Engineer"));
        assert_eq!(
            contact.business_home_page.as_deref(),
            Some("https://doe.org")
        );
        assert_eq!(contact.birthday.as_deref(), Some("1983-04-01T00:00:00Z"));
        assert_eq!(contact.spouse_name.as_deref(), Some("John Doe"));
        assert_eq!(
            contact.children.as_option().unwrap(),
            &vec!["Jimmy".to_string()]
        );
        assert_eq!(contact.personal_notes.as_deref(), Some("a note"));
        assert_eq!(
            contact.categories.as_option().unwrap(),
            &vec!["friends".to_string(), "band".to_string()]
        );
    }

    #[test]
    fn from_vcard_clears_absent_managed_fields_and_keeps_unmanaged_unset() {
        let vcard = "BEGIN:VCARD\r\nVERSION:4.0\r\nFN:X\r\nEND:VCARD\r\n";
        let contact = MsgraphContact::from_vcard(vcard).unwrap();

        assert_eq!(contact.spouse_name, MsgraphField::Null);
        assert_eq!(contact.mobile_phone, MsgraphField::Null);
        assert_eq!(contact.home_address, MsgraphField::Null);
        assert_eq!(contact.business_phones, MsgraphField::Set(vec![]));
        assert_eq!(contact.email_addresses, MsgraphField::Set(vec![]));

        assert_eq!(contact.file_as, MsgraphField::Unset);
        assert_eq!(contact.assistant_name, MsgraphField::Unset);
        assert_eq!(contact.manager, MsgraphField::Unset);
        assert_eq!(contact.office_location, MsgraphField::Unset);
    }

    #[test]
    fn update_from_vcard_keeps_only_changed_fields() {
        let base = "BEGIN:VCARD\r\nVERSION:4.0\r\nFN:Jane Doe\r\n\
            TEL;TYPE=cell:+333333\r\nEMAIL:jane@doe.org\r\n\
            NOTE:a note\r\nEND:VCARD\r\n";
        let edited = "BEGIN:VCARD\r\nVERSION:4.0\r\nFN:Jane Doe\r\n\
            TEL;TYPE=cell:+444444\r\nEMAIL:jane@doe.org\r\nEND:VCARD\r\n";

        let contact = MsgraphContact::update_from_vcard(edited, base).unwrap();

        assert_eq!(contact.mobile_phone.as_deref(), Some("+444444"));
        assert_eq!(contact.personal_notes, MsgraphField::Null);

        // NOTE: unchanged on both sides means out of the body, since a
        // gratuitous null is what the Outlook backend chokes on.
        assert_eq!(contact.display_name, MsgraphField::Unset);
        assert_eq!(contact.email_addresses, MsgraphField::Unset);
        assert_eq!(contact.birthday, MsgraphField::Unset);
        assert_eq!(contact.home_address, MsgraphField::Unset);
        assert_eq!(contact.categories, MsgraphField::Unset);
    }

    #[test]
    fn update_from_vcard_clears_collections_with_empty_sets() {
        let base = "BEGIN:VCARD\r\nVERSION:4.0\r\nFN:X\r\n\
            TEL;TYPE=home:+332222\r\nCATEGORIES:friends\r\nEND:VCARD\r\n";
        let edited = "BEGIN:VCARD\r\nVERSION:4.0\r\nFN:X\r\nEND:VCARD\r\n";

        let contact = MsgraphContact::update_from_vcard(edited, base).unwrap();
        assert_eq!(contact.home_phones, MsgraphField::Set(vec![]));
        assert_eq!(contact.categories, MsgraphField::Set(vec![]));
    }

    #[test]
    fn update_from_vcard_of_identical_cards_is_empty() {
        let vcard = (full_contact()).to_vcard();
        let contact = MsgraphContact::update_from_vcard(&vcard, &vcard).unwrap();
        assert_eq!(contact, MsgraphContact::default());
    }

    #[test]
    fn create_from_vcard_drops_nulls_and_empty_collections() {
        let vcard = "BEGIN:VCARD\r\nVERSION:3.0\r\nFN:X\r\nTEL;TYPE=CELL:+331111\r\nEND:VCARD\r\n";
        let contact = MsgraphContact::create_from_vcard(vcard).unwrap();

        assert_eq!(contact.display_name.as_deref(), Some("X"));
        assert_eq!(contact.mobile_phone.as_deref(), Some("+331111"));
        assert_eq!(contact.spouse_name, MsgraphField::Unset);
        assert_eq!(contact.home_address, MsgraphField::Unset);
        assert_eq!(contact.business_phones, MsgraphField::Unset);
        assert_eq!(contact.email_addresses, MsgraphField::Unset);
    }

    #[test]
    fn from_vcard_respects_graph_slots() {
        let vcard = "BEGIN:VCARD\r\nVERSION:4.0\r\nFN:X\r\n\
            TEL;TYPE=cell:+331111\r\nTEL;TYPE=cell:+332222\r\n\
            TEL;TYPE=work:+333331\r\nTEL;TYPE=work:+333332\r\nTEL:+333333\r\n\
            TEL;TYPE=home:+334441\r\nTEL;TYPE=home:+334442\r\nTEL;TYPE=home:+334443\r\n\
            ADR;TYPE=home:;;First St;;;;\r\nADR;TYPE=home:;;Second St;;;;\r\n\
            EMAIL:a@x.org\r\nEMAIL:b@x.org\r\nEMAIL:c@x.org\r\nEMAIL:d@x.org\r\n\
            IMPP:xmpp:a@x.org\r\nIMPP:xmpp:b@x.org\r\nIMPP:xmpp:c@x.org\r\nIMPP:xmpp:d@x.org\r\n\
            RELATED;TYPE=spouse:urn:uuid:03a0e51f\r\nEND:VCARD\r\n";

        let contact = MsgraphContact::from_vcard(vcard).unwrap();

        // NOTE: one mobile slot, so the second cell TEL is dropped
        // rather than misfiled as a business phone.
        assert_eq!(contact.mobile_phone.as_deref(), Some("+331111"));

        assert_eq!(
            contact.business_phones.as_option().unwrap(),
            &vec!["+333331".to_string(), "+333332".to_string()]
        );
        assert_eq!(
            contact.home_phones.as_option().unwrap(),
            &vec!["+334441".to_string(), "+334442".to_string()]
        );
        assert_eq!(contact.email_addresses.as_option().unwrap().len(), 3);
        assert_eq!(contact.im_addresses.as_option().unwrap().len(), 3);

        let home = contact.home_address.as_option().unwrap();
        assert_eq!(home.street.as_deref(), Some("First St"));
        assert_eq!(contact.spouse_name, MsgraphField::Null);
    }

    #[test]
    fn round_trip() {
        let contact = full_contact();

        // NOTE: the full-state projection always carries the (empty)
        // stash slot, so a cleared stash is distinguishable from an
        // unchanged one.
        let mut expected = contact.clone();
        expected.single_value_extended_properties =
            MsgraphField::Set(vec![MsgraphSingleValueExtendedProperty {
                id: MSGRAPH_CONTACT_STASH_ID.to_string(),
                value: String::new(),
            }]);

        assert_eq!(
            MsgraphContact::from_vcard(&contact.to_vcard()).unwrap(),
            expected
        );
    }

    #[test]
    fn stash_preserves_unprojected_props() {
        let vcard = "BEGIN:VCARD\r\nVERSION:4.0\r\nFN:X\r\nX-FOO;TYPE=bar:baz\r\n\
            EMAIL:a@x.org\r\nEMAIL:b@x.org\r\nEMAIL:c@x.org\r\nEMAIL:d@x.org\r\nEND:VCARD\r\n";

        let contact = MsgraphContact::from_vcard(vcard).unwrap();
        let props = contact
            .single_value_extended_properties
            .as_option()
            .unwrap();
        assert_eq!(props[0].id, MSGRAPH_CONTACT_STASH_ID);
        assert_eq!(props[0].value, "X-FOO;TYPE=bar:baz\nEMAIL:d@x.org");

        let restored = (contact).to_vcard();
        assert!(restored.contains("X-FOO;TYPE=bar:baz\r\n"));
        assert!(restored.contains("EMAIL:d@x.org\r\n"));
        assert!(restored.ends_with("END:VCARD\r\n"));
    }

    #[test]
    fn minted_props_project_and_consume() {
        let mut contact = full_contact();
        contact.file_as = MsgraphField::Set("Doe, Jane".into());
        contact.office_location = MsgraphField::Set("B2".into());
        contact.assistant_name = MsgraphField::Set("Sam".into());
        contact.manager = MsgraphField::Set("Alex".into());

        let vcard = (contact).to_vcard();
        assert!(vcard.contains("X-MSGRAPH-FILE-AS:Doe\\, Jane\r\n"));
        assert!(vcard.contains("X-MSGRAPH-OFFICE-LOCATION:B2\r\n"));
        assert!(vcard.contains("X-MSGRAPH-ASSISTANT:Sam\r\n"));
        assert!(vcard.contains("X-MSGRAPH-MANAGER:Alex\r\n"));

        // NOTE: consumed on the way back, so the fields stay Unset and
        // the lines stay out of the stash.
        let back = MsgraphContact::from_vcard(&vcard).unwrap();
        assert_eq!(back.file_as, MsgraphField::Unset);
        assert_eq!(back.office_location, MsgraphField::Unset);
        assert_eq!(back.assistant_name, MsgraphField::Unset);
        assert_eq!(back.manager, MsgraphField::Unset);
        let props = back.single_value_extended_properties.as_option().unwrap();
        assert_eq!(props[0].value, "");
    }

    #[test]
    fn update_from_vcard_tracks_the_stash() {
        let base = "BEGIN:VCARD\r\nVERSION:4.0\r\nFN:X\r\nX-FOO:bar\r\nEND:VCARD\r\n";
        let unchanged = MsgraphContact::update_from_vcard(base, base).unwrap();
        assert_eq!(
            unchanged.single_value_extended_properties,
            MsgraphField::Unset
        );

        let cleared = "BEGIN:VCARD\r\nVERSION:4.0\r\nFN:X\r\nEND:VCARD\r\n";
        let delta = MsgraphContact::update_from_vcard(cleared, base).unwrap();
        let props = delta.single_value_extended_properties.as_option().unwrap();
        assert_eq!(props[0].value, "");
    }

    #[test]
    fn create_from_vcard_drops_the_empty_stash() {
        let vcard = "BEGIN:VCARD\r\nVERSION:4.0\r\nFN:X\r\nEND:VCARD\r\n";
        let contact = MsgraphContact::create_from_vcard(vcard).unwrap();
        assert_eq!(
            contact.single_value_extended_properties,
            MsgraphField::Unset
        );

        let vcard = "BEGIN:VCARD\r\nVERSION:4.0\r\nFN:X\r\nX-FOO:bar\r\nEND:VCARD\r\n";
        let contact = MsgraphContact::create_from_vcard(vcard).unwrap();
        let props = contact
            .single_value_extended_properties
            .as_option()
            .unwrap();
        assert_eq!(props[0].value, "X-FOO:bar");
    }

    #[test]
    fn the_expand_clause_names_the_stash() {
        let quoted = format!("'{MSGRAPH_CONTACT_STASH_ID}'");
        assert!(MSGRAPH_CONTACT_STASH_EXPAND.contains(&quoted));
    }

    #[test]
    fn a_vcard_uid_rides_the_stash_and_wins_over_the_graph_id() {
        let vcard = "BEGIN:VCARD\r\nVERSION:4.0\r\nUID:urn:uuid:4fbe8971\r\n\
            FN:Jane Doe\r\nEND:VCARD\r\n";

        let mut contact = MsgraphContact::create_from_vcard(vcard).unwrap();
        // NOTE: what Graph hands back after the create: its own id, and the
        // stash it was given.
        contact.id = "AAMkAGI2".into();

        assert_eq!(contact.stashed_uid().as_deref(), Some("urn:uuid:4fbe8971"));
        let vcard = contact.to_vcard();
        assert!(vcard.contains("UID:urn:uuid:4fbe8971\r\n"));
        assert!(!vcard.contains("UID:AAMkAGI2"));
    }

    #[test]
    fn a_contact_graph_created_mints_its_uid_from_the_graph_id() {
        let contact = MsgraphContact {
            id: "AAMkAGI2".into(),
            display_name: MsgraphField::Set("Jane Doe".into()),
            ..Default::default()
        };

        assert_eq!(contact.stashed_uid(), None);
        assert!(contact.to_vcard().contains("UID:AAMkAGI2\r\n"));
    }
}