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kompress_eshop/src/shared/pricing.rs
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now products have different options, like different parameters
2026-06-22 15:44:02 +02:00

478 lines
16 KiB
Rust

//! Single source of truth for the price a given viewer pays for a product, so
//! the storefront, cart, and placed orders always agree.
//!
//! Layers, all combined by "lowest wins":
//! - **Personal price** (everyone, incl. anonymous): the lower of the regular
//! price, the public sale (`products.sale_price_cents`), and any discount
//! profiles assigned to the *personal* audience on the discounts page.
//! - **Business price** (company accounts): the lower of the personal price, the
//! global business baseline (`products.business_sale_price_cents`), discount
//! profiles assigned to the *business* audience, the company's own assigned
//! profiles, and the company's manually negotiated price.
//!
//! A company therefore always pays the lowest of personal vs business.
use std::collections::{HashMap, HashSet};
use loco_rs::prelude::*;
use sea_orm::{ColumnTrait, EntityTrait, QueryFilter};
use crate::models::{
account_discount_profiles, account_product_prices, account_product_resolutions,
audience_discount_profiles, discount_profile_products, discount_profiles, product_variants,
users,
};
use crate::shared::money::apply_discount_bp;
/// `account_type` value that unlocks business pricing.
const COMPANY: &str = "company";
const AUDIENCE_PERSONAL: &str = "personal";
const AUDIENCE_BUSINESS: &str = "business";
/// The resolved price for one product and one viewer (the slim shape templates
/// and the cart use).
#[derive(Debug, Clone, Copy)]
pub struct PricedProduct {
pub price_cents: i64,
pub regular_cents: i64,
/// True when a business-specific deal (not just the personal price) won.
pub is_business: bool,
}
impl PricedProduct {
#[must_use]
pub fn is_reduced(&self) -> bool {
self.price_cents < self.regular_cents
}
}
/// Full breakdown for one product and one viewer, used by the admin company page.
#[derive(Debug, Clone)]
pub struct PriceDetail {
pub regular_cents: i64,
/// The personal price (what non-business viewers pay).
pub public_cents: i64,
pub manual_cents: Option<i64>,
pub auto_cents: Option<i64>,
pub auto_profile_id: Option<i32>,
pub covering_profile_ids: Vec<i32>,
pub collision: bool,
pub price_cents: i64,
pub is_business: bool,
}
impl PriceDetail {
fn public_only(regular_cents: i64, public_cents: i64) -> Self {
Self {
regular_cents,
public_cents,
manual_cents: None,
auto_cents: None,
auto_profile_id: None,
covering_profile_ids: Vec::new(),
collision: false,
price_cents: public_cents,
is_business: false,
}
}
#[must_use]
pub fn priced(&self) -> PricedProduct {
PricedProduct {
price_cents: self.price_cents,
regular_cents: self.regular_cents,
is_business: self.is_business,
}
}
}
/// The "lowest wins" decision: take the business price only when it is at or
/// below the personal price. Pure, so it is unit-tested directly.
fn decide(regular_cents: i64, personal_cents: i64, business: Option<i64>) -> PricedProduct {
match business {
Some(b) if b <= personal_cents => PricedProduct {
price_cents: b,
regular_cents,
is_business: true,
},
_ => PricedProduct {
price_cents: personal_cents,
regular_cents,
is_business: false,
},
}
}
fn is_company(user: Option<&users::Model>) -> bool {
matches!(user, Some(u) if u.account_type == COMPANY)
}
/// `min` of `Option`s, ignoring `None`s.
fn lowest(values: [Option<i64>; 4]) -> Option<i64> {
values.into_iter().flatten().min()
}
/// A set of discount profiles plus their product membership, with the logic to
/// price a product against them.
struct LoadedProfiles {
profiles: Vec<discount_profiles::Model>,
membership: HashMap<i32, HashSet<i32>>,
}
impl LoadedProfiles {
fn empty() -> Self {
Self {
profiles: Vec::new(),
membership: HashMap::new(),
}
}
/// The best (lowest) price any covering profile produces off the regular
/// price, or `None` when no profile covers the product.
fn best_price(&self, regular_cents: i64, product_id: i32) -> Option<i64> {
let empty = HashSet::new();
self.profiles
.iter()
.filter(|p| p.covers(product_id, self.membership.get(&p.id).unwrap_or(&empty)))
.map(|p| apply_discount_bp(regular_cents, p.percent_bp))
.min()
}
/// Every profile that covers a product (for the per-company collision UI).
fn covering(&self, product_id: i32) -> Vec<&discount_profiles::Model> {
let empty = HashSet::new();
self.profiles
.iter()
.filter(|p| p.covers(product_id, self.membership.get(&p.id).unwrap_or(&empty)))
.collect()
}
}
async fn load_membership(
ctx: &AppContext,
profile_ids: &[i32],
) -> Result<HashMap<i32, HashSet<i32>>> {
let mut membership: HashMap<i32, HashSet<i32>> = HashMap::new();
if profile_ids.is_empty() {
return Ok(membership);
}
let rows = discount_profile_products::Entity::find()
.filter(discount_profile_products::Column::DiscountProfileId.is_in(profile_ids.to_vec()))
.all(&ctx.db)
.await?;
for row in rows {
membership
.entry(row.discount_profile_id)
.or_default()
.insert(row.product_id);
}
Ok(membership)
}
async fn load_profiles_by_ids(ctx: &AppContext, ids: Vec<i32>) -> Result<LoadedProfiles> {
if ids.is_empty() {
return Ok(LoadedProfiles::empty());
}
let profiles = discount_profiles::Entity::find()
.filter(discount_profiles::Column::Id.is_in(ids.clone()))
.all(&ctx.db)
.await?;
let membership = load_membership(ctx, &ids).await?;
Ok(LoadedProfiles {
profiles,
membership,
})
}
/// Profiles assigned globally to an audience on the discounts page.
async fn load_audience(ctx: &AppContext, audience: &str) -> Result<LoadedProfiles> {
let ids: Vec<i32> = audience_discount_profiles::Entity::find()
.filter(audience_discount_profiles::Column::Audience.eq(audience))
.all(&ctx.db)
.await?
.into_iter()
.map(|a| a.discount_profile_id)
.collect();
load_profiles_by_ids(ctx, ids).await
}
/// Per-company pricing inputs (manual prices, assigned profiles, resolutions).
struct B2bContext {
manual: HashMap<i32, i64>,
profiles: LoadedProfiles,
resolutions: HashMap<i32, i32>,
}
async fn load_b2b(ctx: &AppContext, user_id: i32) -> Result<B2bContext> {
let manual = account_product_prices::Model::map_for_user(&ctx.db, user_id).await?;
let ids: Vec<i32> = account_discount_profiles::Entity::find()
.filter(account_discount_profiles::Column::UserId.eq(user_id))
.all(&ctx.db)
.await?
.into_iter()
.map(|a| a.discount_profile_id)
.collect();
let profiles = load_profiles_by_ids(ctx, ids).await?;
let resolutions = account_product_resolutions::Entity::find()
.filter(account_product_resolutions::Column::UserId.eq(user_id))
.all(&ctx.db)
.await?
.into_iter()
.map(|r| (r.variant_id, r.discount_profile_id))
.collect();
Ok(B2bContext {
manual,
profiles,
resolutions,
})
}
/// Everything loaded once per request to price any product for the viewer.
struct PricingCtx {
personal: LoadedProfiles,
business: LoadedProfiles,
b2b: Option<B2bContext>,
}
/// Resolve the per-company automated price for a variant. Discount profiles
/// cover the *product* (`product_id`); the admin's collision resolution is set
/// per *variant* (`variant_id`). Result: the single covering profile, the
/// admin-resolved winner on a collision, or (unresolved) the biggest discount,
/// flagged.
fn company_auto(
b2b: &B2bContext,
regular_cents: i64,
product_id: i32,
variant_id: i32,
) -> (Option<i64>, Option<i32>, bool, Vec<i32>) {
let covering = b2b.profiles.covering(product_id);
let ids: Vec<i32> = covering.iter().map(|p| p.id).collect();
if covering.is_empty() {
return (None, None, false, ids);
}
let (chosen, collision) = if covering.len() == 1 {
(covering[0], false)
} else {
match b2b
.resolutions
.get(&variant_id)
.and_then(|rid| covering.iter().find(|p| p.id == *rid).copied())
{
Some(resolved) => (resolved, false),
None => (
covering
.iter()
.max_by_key(|p| p.percent_bp)
.copied()
.expect("covering is non-empty"),
true,
),
}
};
(
Some(apply_discount_bp(regular_cents, chosen.percent_bp)),
Some(chosen.id),
collision,
ids,
)
}
fn detail_for_variant(variant: &product_variants::Model, pc: &PricingCtx) -> PriceDetail {
let regular = variant.price_cents;
let product_id = variant.product_id;
// Personal price: the variant's own public sale + personal-audience profiles
// (which cover the product), lowest wins.
let personal_sale = variant.effective_price_cents();
let personal_profile = pc.personal.best_price(regular, product_id);
let personal_effective = personal_profile
.map_or(personal_sale, |p| personal_sale.min(p));
let Some(b2b) = &pc.b2b else {
return PriceDetail::public_only(regular, personal_effective);
};
// Business candidates (company accounts only). The negotiated price is keyed
// to the variant; the baseline business sale lives on the variant.
let manual = b2b.manual.get(&variant.id).copied();
let (auto_cents, auto_profile_id, collision, covering_ids) =
company_auto(b2b, regular, product_id, variant.id);
let business_global = variant.business_sale_price_cents;
let business_profile = pc.business.best_price(regular, product_id);
let business_best = lowest([manual, auto_cents, business_global, business_profile]);
let priced = decide(regular, personal_effective, business_best);
PriceDetail {
regular_cents: regular,
public_cents: personal_effective,
manual_cents: manual,
auto_cents,
auto_profile_id,
covering_profile_ids: covering_ids,
collision,
price_cents: priced.price_cents,
is_business: priced.is_business,
}
}
async fn load_pricing_ctx(ctx: &AppContext, user: Option<&users::Model>) -> Result<PricingCtx> {
let personal = load_audience(ctx, AUDIENCE_PERSONAL).await?;
let (business, b2b) = if is_company(user) {
(
load_audience(ctx, AUDIENCE_BUSINESS).await?,
Some(load_b2b(ctx, user.expect("is_company implies Some").id).await?),
)
} else {
(LoadedProfiles::empty(), None)
};
Ok(PricingCtx {
personal,
business,
b2b,
})
}
/// Full breakdowns for many variants for `user`, batching per-request lookups.
pub async fn detail_variants(
ctx: &AppContext,
list: &[product_variants::Model],
user: Option<&users::Model>,
) -> Result<Vec<PriceDetail>> {
let pc = load_pricing_ctx(ctx, user).await?;
Ok(list.iter().map(|v| detail_for_variant(v, &pc)).collect())
}
/// Effective prices for a whole audience using only the global layers (the
/// per-product sale + audience-assigned profiles + the business baseline), with
/// no specific company's per-company deals. Used by the discounts admin page to
/// preview what each tab's discounts produce. `audience` is "personal" or
/// "business".
pub async fn audience_price_variants(
ctx: &AppContext,
list: &[product_variants::Model],
audience: &str,
) -> Result<Vec<PricedProduct>> {
let personal = load_audience(ctx, AUDIENCE_PERSONAL).await?;
let (business, b2b) = if audience == AUDIENCE_BUSINESS {
(
load_audience(ctx, AUDIENCE_BUSINESS).await?,
// A generic company with no per-company profiles/negotiated prices.
Some(B2bContext {
manual: HashMap::new(),
profiles: LoadedProfiles::empty(),
resolutions: HashMap::new(),
}),
)
} else {
(LoadedProfiles::empty(), None)
};
let pc = PricingCtx {
personal,
business,
b2b,
};
Ok(list.iter().map(|v| detail_for_variant(v, &pc).priced()).collect())
}
/// Like [`audience_price_many`], but prices against an *unsaved* set of profile
/// ids for the active audience instead of the persisted assignment. Used by the
/// products page to preview effective prices as the admin toggles profile
/// checkboxes, before they hit Save. For the business tab the personal layer
/// stays the persisted one (businesses get the lower of personal/business), and
/// only the business layer is replaced by the previewed selection.
pub async fn audience_price_variants_preview(
ctx: &AppContext,
list: &[product_variants::Model],
audience: &str,
selected_profile_ids: Vec<i32>,
) -> Result<Vec<PricedProduct>> {
let preview = load_profiles_by_ids(ctx, selected_profile_ids).await?;
let (personal, business, b2b) = if audience == AUDIENCE_BUSINESS {
(
load_audience(ctx, AUDIENCE_PERSONAL).await?,
preview,
Some(B2bContext {
manual: HashMap::new(),
profiles: LoadedProfiles::empty(),
resolutions: HashMap::new(),
}),
)
} else {
(preview, LoadedProfiles::empty(), None)
};
let pc = PricingCtx {
personal,
business,
b2b,
};
Ok(list.iter().map(|v| detail_for_variant(v, &pc).priced()).collect())
}
/// Price one variant for `user` (`None` = anonymous/public).
pub async fn price_variant(
ctx: &AppContext,
variant: &product_variants::Model,
user: Option<&users::Model>,
) -> Result<PricedProduct> {
let detail = detail_variants(ctx, std::slice::from_ref(variant), user).await?;
Ok(detail[0].priced())
}
/// Price many variants for `user`, batching the per-request lookups.
pub async fn price_variants(
ctx: &AppContext,
list: &[product_variants::Model],
user: Option<&users::Model>,
) -> Result<Vec<PricedProduct>> {
Ok(detail_variants(ctx, list, user)
.await?
.iter()
.map(PriceDetail::priced)
.collect())
}
#[cfg(test)]
mod tests {
use super::decide;
use crate::shared::money::apply_discount_bp;
#[test]
fn personal_only() {
let p = decide(10000, 10000, None);
assert_eq!(p.price_cents, 10000);
assert!(!p.is_business);
}
#[test]
fn business_lower_wins() {
let p = decide(10000, 10000, Some(9000));
assert_eq!(p.price_cents, 9000);
assert!(p.is_business);
}
#[test]
fn personal_beats_business() {
// personal already 80 (e.g. personal profile), business best 90 -> 80.
let p = decide(10000, 8000, Some(9000));
assert_eq!(p.price_cents, 8000);
assert!(!p.is_business);
}
#[test]
fn business_equal_is_business() {
let p = decide(10000, 10000, Some(10000));
assert_eq!(p.price_cents, 10000);
assert!(p.is_business);
}
#[test]
fn discount_bp_rounds_half_up() {
assert_eq!(apply_discount_bp(10000, 500), 9500);
assert_eq!(apply_discount_bp(10000, 1500), 8500);
assert_eq!(apply_discount_bp(10000, 0), 10000);
}
}