actix-cloud-extra 0.1.5

//! REST API helpers: pagination parameters, dynamic query condition building
//! and common request payloads.

use std::cmp;
#[cfg(feature = "seaorm")]
use std::collections::BTreeMap;
use std::hash::Hash;

use actix_cloud::utils;
use anyhow::Result;
use derivative::Derivative;
#[cfg(feature = "seaorm")]
use sea_orm::{
    ExprTrait as _, FromQueryResult, Order, QueryOrder as _,
    entity::prelude::async_trait::async_trait,
    prelude::*,
    sea_query::{ColumnRef, LikeExpr, SimpleExpr},
};
use serde::{Deserialize, Serialize};
use serde_inline_default::serde_inline_default;
use validator::{Validate, ValidationError};

use crate::HyUuid;
#[cfg(feature = "entity")]
use crate::entity::DefaultColumnTrait;
#[cfg(feature = "seaorm")]
use crate::utils::StringUtil as _;

/// Standard paginated response: total item count plus one page of data.
#[derive(Serialize, Debug)]
pub struct PageData<T> {
    /// Total number of items across all pages.
    pub total: u64,
    /// Items of the requested page.
    pub data: Vec<T>,
}

impl<T> PageData<T> {
    /// Build from a `(data, total)` tuple, e.g. as returned by
    /// `Condition::select_page` or [`PaginationParam::split`].
    pub fn new(data: (Vec<T>, u64)) -> Self {
        Self {
            total: data.1,
            data: data.0,
        }
    }
}

/// Pagination parameters (`page` / `size`) accepted from query or body.
///
/// Both fields fall back to defaults (page 1, size 10) when missing. Call
/// `validate` (from `validator`) to enforce `page >= 1` and
/// `1 <= size <= 100`.
#[serde_inline_default]
#[derive(Derivative, Deserialize, Validate, Clone, Debug)]
#[derivative(Default(new = "true"))]
pub struct PaginationParam {
    /// 1-based page index.
    #[validate(range(min = 1))]
    #[serde_inline_default(1)]
    #[derivative(Default(value = "1"))]
    pub page: u64,

    /// Number of items per page, capped at 100 by validation.
    #[validate(range(min = 1, max = 100))]
    #[serde_inline_default(10)]
    #[derivative(Default(value = "10"))]
    pub size: u64,
}

impl PaginationParam {
    /// 0-based index of the first item of the page (saturating).
    pub fn left(&self) -> u64 {
        self.page.saturating_sub(1).saturating_mul(self.size)
    }

    /// Exclusive 0-based end index of the page (saturating).
    pub fn right(&self) -> u64 {
        self.page.saturating_mul(self.size)
    }

    /// Clamp a `u64` offset/count down to [`usize`] so it can be used for
    /// in-memory slicing on any platform.
    pub fn round(p: u64) -> usize {
        cmp::min(p, usize::MAX as u64) as usize
    }

    /// Apply the pagination to an in-memory list, returning the requested page
    /// plus the total item count.
    pub fn split<T>(&self, data: Vec<T>) -> PageData<T> {
        let cnt = data.len();
        PageData::new((
            data.into_iter()
                .skip(Self::round(self.left()))
                .take(Self::round(self.size))
                .collect(),
            cnt as u64,
        ))
    }
}

/// Extension for SeaORM `Select`: execute a query with optional pagination and
/// get back `(items, total_count)`.
#[cfg(feature = "seaorm")]
#[async_trait]
pub trait SelectPage<E, C>
where
    E: EntityTrait,
    C: ConnectionTrait,
{
    /// Fetch one page when `p` is given, or the whole result set (with its
    /// length as total) otherwise.
    async fn select_page(self, db: &C, p: Option<PaginationParam>) -> Result<(Vec<E::Model>, u64)>;
}

#[cfg(feature = "seaorm")]
#[async_trait]
impl<M, E, C> SelectPage<E, C> for Select<E>
where
    E: EntityTrait<Model = M>,
    M: FromQueryResult + Sized + Send + Sync,
    C: ConnectionTrait,
{
    async fn select_page(self, db: &C, p: Option<PaginationParam>) -> Result<(Vec<E::Model>, u64)> {
        if let Some(page) = p {
            let q = self.paginate(db, page.size);
            Ok((
                q.fetch_page(page.page.saturating_sub(1)).await?,
                q.num_items().await?,
            ))
        } else {
            let res = self.all(db).await?;
            let cnt = res.len() as u64;
            Ok((res, cnt))
        }
    }
}

/// Helpers to turn strings into SeaORM/SeaQuery expressions.
#[cfg(feature = "seaorm")]
pub trait IntoExpr {
    /// Build `col LIKE '%<self>%'`, escaping `\`, `%` and `_` in `self`.
    fn like_expr<T>(&self, col: T) -> SimpleExpr
    where
        T: ColumnTrait;
}

#[cfg(feature = "seaorm")]
impl IntoExpr for &String {
    fn like_expr<T>(&self, col: T) -> SimpleExpr
    where
        T: ColumnTrait,
    {
        sea_orm::prelude::Expr::col((col.entity_name(), col))
            .like(LikeExpr::new(format!("%{}%", self.like_escape())).escape('\\'))
    }
}

/// The query condition hub: filters + optional pagination + sort order.
///
/// Built fluently, then applied to a SeaORM `Select` via [`Condition::build`]
/// or executed directly with [`Condition::select_page`]. All CRUD helpers
/// generated by the `default_viewer` macro funnel through it.
#[cfg(feature = "seaorm")]
pub struct Condition {
    /// Optional SQL pagination.
    pub page: Option<PaginationParam>,
    /// WHERE filters, `all()` by default.
    pub cond: sea_orm::Condition,
    /// Sort expressions, applied in insertion order.
    pub order: Vec<(SimpleExpr, Order)>,
}

#[cfg(feature = "seaorm")]
impl Default for Condition {
    fn default() -> Self {
        Self {
            cond: sea_orm::Condition::all(),
            page: None,
            order: Vec::new(),
        }
    }
}

#[cfg(feature = "seaorm")]
impl From<sea_orm::Condition> for Condition {
    fn from(cond: sea_orm::Condition) -> Self {
        Self::new(cond)
    }
}

#[cfg(feature = "seaorm")]
impl Condition {
    /// Wrap an existing [`sea_orm::Condition`] as filters.
    pub fn new(cond: sea_orm::Condition) -> Self {
        Self {
            cond,
            page: None,
            order: Vec::new(),
        }
    }

    /// New condition matching everything (`all()`).
    pub fn new_all() -> Self {
        Self::new(Self::all())
    }

    /// New condition matching anything (`any()`).
    pub fn new_any() -> Self {
        Self::new(Self::any())
    }

    /// Append one sort expression; later calls take precedence for ties.
    pub fn add_sort(mut self, col: SimpleExpr, sort: Order) -> Self {
        self.order.push((col, sort));
        self
    }

    /// Attach SQL pagination.
    pub fn add_page(mut self, page: PaginationParam) -> Self {
        self.page = Some(page);
        self
    }

    /// Parse the sort string when present, see [`Condition::parse_sort`].
    pub fn parse_sort_option(mut self, str: &Option<String>, col: Vec<ColumnRef>) -> Self {
        if let Some(str) = str {
            self = self.parse_sort(str, col)
        }
        self
    }

    /// Parse a sort string like `-created_at,+name` into sort expressions.
    ///
    /// `-`/`+` prefixes select descending/ascending order (no prefix =
    /// ascending); names not present in the `col` whitelist are silently
    /// ignored, so this is safe to feed straight from user input.
    pub fn parse_sort(mut self, str: &str, col: Vec<ColumnRef>) -> Self {
        let mut allow: BTreeMap<String, ColumnRef> = col
            .into_iter()
            .map(|x| (x.column().unwrap().to_string(), x))
            .collect();
        for i in str.split(',') {
            let order = if i.starts_with('-') {
                Order::Desc
            } else {
                Order::Asc
            };
            let name = i
                .strip_prefix('+')
                .or_else(|| i.strip_prefix('-'))
                .unwrap_or(i);
            if let Some(x) = allow.remove(name) {
                self = self.add_sort(SimpleExpr::Column(x), order);
            }
        }
        self
    }

    /// Shortcut of [`sea_orm::Condition::any`].
    pub fn any() -> sea_orm::Condition {
        sea_orm::Condition::any()
    }

    /// Shortcut of [`sea_orm::Condition::all`].
    pub fn all() -> sea_orm::Condition {
        sea_orm::Condition::all()
    }

    /// AND one more condition.
    #[allow(clippy::should_implement_trait)]
    pub fn add<C>(mut self, condition: C) -> Self
    where
        C: Into<sea_orm::Condition>,
    {
        self.cond = self.cond.add(condition.into());
        self
    }

    /// AND one more condition, ignored when `None`.
    pub fn add_option<C>(mut self, condition: Option<C>) -> Self
    where
        C: Into<sea_orm::Condition>,
    {
        self.cond = self.cond.add_option(condition);
        self
    }

    /// Apply the sort order and filters to a `Select`.
    ///
    /// Returns the built query together with the detached pagination, ready
    /// for [`SelectPage::select_page`].
    pub fn build<E>(self, mut q: Select<E>) -> (Select<E>, Option<PaginationParam>)
    where
        E: EntityTrait,
    {
        for i in self.order {
            q = q.order_by(i.0, i.1);
        }
        (q.filter(self.cond), self.page)
    }

    /// [`Condition::build`] + [`SelectPage::select_page`] in one call;
    /// returns `(items, total_count)`.
    pub async fn select_page<M, E, C>(self, q: Select<E>, db: &C) -> Result<(Vec<E::Model>, u64)>
    where
        E: EntityTrait<Model = M>,
        M: FromQueryResult + Sized + Send + Sync,
        C: ConnectionTrait,
    {
        let (q, page) = self.build(q);
        q.select_page(db, page).await
    }

    /// Add created/updated time range filters from [`TimeParam`], using the
    /// columns provided by [`DefaultColumnTrait`] (usually implemented by the
    /// `entity_timestamp` macro).
    #[cfg(feature = "entity")]
    pub fn add_time<T>(mut self, p: &TimeParam) -> Self
    where
        T: DefaultColumnTrait,
    {
        self = self.add_option(p.created_start.map(|x| T::get_created_at().gte(x)));
        self = self.add_option(p.created_end.map(|x| T::get_created_at().lte(x)));
        self = self.add_option(p.updated_start.map(|x| T::get_updated_at().gte(x)));
        self = self.add_option(p.updated_end.map(|x| T::get_updated_at().lte(x)));
        self
    }
}

/// `validator` helper checking that a list contains no duplicate items.
///
/// # Errors
/// Will return `Err` when `x` has duplicate items.
pub fn unique_validator<T: Eq + Hash>(x: &Vec<T>) -> Result<(), ValidationError> {
    if utils::is_unique(x) {
        Ok(())
    } else {
        Err(ValidationError::new("not unique"))
    }
}

/// Request payload carrying a list of unique IDs.
#[derive(Debug, Validate, Deserialize)]
pub struct IDsReq {
    /// Entity IDs, must not contain duplicates.
    #[validate(custom(function = "unique_validator"))]
    pub id: Vec<HyUuid>,
}

/// Request payload carrying an optional list of unique IDs.
#[derive(Debug, Validate, Deserialize)]
pub struct OptionIDsReq {
    /// Entity IDs, must not contain duplicates.
    #[validate(custom(function = "unique_validator"))]
    pub id: Option<Vec<HyUuid>>,
}

/// Created/updated time range filters, consumed by
/// [`Condition::add_time`].
///
/// All values are naive UTC datetimes, the same type the `entity_timestamp`
/// macro stores, and deserialize from *strings* like `2024-01-01T00:00:00`
/// (`T` separator required, fractional seconds optional).
#[cfg(feature = "seaorm")]
#[derive(Debug, Deserialize, Validate)]
pub struct TimeParam {
    /// `created_at >= created_start` filter.
    pub created_start: Option<DateTime>,
    /// `created_at <= created_end` filter.
    pub created_end: Option<DateTime>,

    /// `updated_at >= updated_start` filter.
    pub updated_start: Option<DateTime>,
    /// `updated_at <= updated_end` filter.
    pub updated_end: Option<DateTime>,
}

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

    #[test]
    fn page_data_new() {
        let page = PageData::new((vec![1, 2, 3], 7));
        assert_eq!(page.total, 7);
        assert_eq!(page.data, vec![1, 2, 3]);
    }

    #[test]
    fn page_data_serialize() {
        let value = serde_json::to_value(PageData::new((vec!["a"], 1))).unwrap();
        assert_eq!(value, serde_json::json!({"total": 1, "data": ["a"]}));
    }

    #[test]
    fn pagination_default() {
        let p = PaginationParam::default();
        assert_eq!((p.page, p.size), (1, 10));
        assert_eq!((p.left(), p.right()), (0, 10));

        let p = PaginationParam::new();
        assert_eq!((p.page, p.size), (1, 10));
    }

    #[test]
    fn pagination_deserialize() {
        let p: PaginationParam = serde_json::from_str(r#"{"page": 2, "size": 20}"#).unwrap();
        assert_eq!((p.page, p.size), (2, 20));
        // Missing fields fall back to defaults.
        let p: PaginationParam = serde_json::from_str("{}").unwrap();
        assert_eq!((p.page, p.size), (1, 10));
        // String numbers are rejected.
        assert!(serde_json::from_str::<PaginationParam>(r#"{"page": "2"}"#).is_err());
    }

    #[test]
    fn pagination_validate() {
        // Deserialization alone does not reject out-of-range values.
        let p: PaginationParam = serde_json::from_str(r#"{"page": 0}"#).unwrap();
        assert!(p.validate().is_err());
        let p: PaginationParam = serde_json::from_str(r#"{"size": 101}"#).unwrap();
        assert!(p.validate().is_err());
        let p: PaginationParam = serde_json::from_str(r#"{"page": 5, "size": 100}"#).unwrap();
        assert!(p.validate().is_ok());
    }

    #[test]
    fn pagination_split() {
        let p = PaginationParam { page: 2, size: 3 };
        let page = p.split(vec![1, 2, 3, 4, 5, 6, 7]);
        assert_eq!(page.total, 7);
        assert_eq!(page.data, vec![4, 5, 6]);
    }

    #[test]
    fn pagination_bounds_saturate() {
        // `page: 0` (only reachable without validation) must not underflow.
        let p = PaginationParam { page: 0, size: 10 };
        assert_eq!((p.left(), p.right()), (0, 0));

        // Huge values saturate instead of overflowing.
        let p = PaginationParam {
            page: u64::MAX,
            size: 100,
        };
        assert_eq!(p.left(), u64::MAX);
        assert_eq!(p.right(), u64::MAX);
        assert_eq!(PaginationParam::round(u64::MAX), usize::MAX as usize);

        // An out-of-range window yields an empty page instead of a panic.
        let page = p.split(vec![1, 2, 3]);
        assert_eq!(page.total, 3);
        assert!(page.data.is_empty());
    }

    #[test]
    fn unique_validator_works() {
        assert!(unique_validator(&Vec::<u8>::new()).is_ok());
        assert!(unique_validator(&vec![1, 2, 3]).is_ok());
        assert!(unique_validator(&vec![1, 2, 2]).is_err());
    }

    #[test]
    fn ids_req_validate() {
        let a = HyUuid::new();
        let b = HyUuid::new();

        let req: IDsReq =
            serde_json::from_value(serde_json::json!({ "id": [a.to_string(), b.to_string()] }))
                .unwrap();
        assert!(req.validate().is_ok());

        // Duplicates pass deserialization but fail validation.
        let req: IDsReq =
            serde_json::from_value(serde_json::json!({ "id": [a.to_string(), a.to_string()] }))
                .unwrap();
        assert!(req.validate().is_err());
    }

    #[test]
    fn option_ids_req_validate() {
        let a = HyUuid::new();

        // Missing or null ids skip validation.
        let req: OptionIDsReq = serde_json::from_value(serde_json::json!({})).unwrap();
        assert!(req.id.is_none());
        assert!(req.validate().is_ok());
        let req: OptionIDsReq = serde_json::from_value(serde_json::json!({ "id": null })).unwrap();
        assert!(req.validate().is_ok());

        let req: OptionIDsReq =
            serde_json::from_value(serde_json::json!({ "id": [a.to_string()] })).unwrap();
        assert!(req.validate().is_ok());
        let req: OptionIDsReq =
            serde_json::from_value(serde_json::json!({ "id": [a.to_string(), a.to_string()] }))
                .unwrap();
        assert!(req.validate().is_err());
    }

    #[cfg(feature = "seaorm")]
    #[test]
    fn time_param_deserialize() {
        let p: TimeParam = serde_json::from_str(
            r#"{"created_start": "2024-01-01T00:00:00", "created_end": "2024-01-01T23:59:59.5"}"#,
        )
        .unwrap();
        assert!(p.created_start.is_some());
        assert!(p.created_end.is_some());
        assert!(p.updated_start.is_none());
        assert!(p.updated_end.is_none());

        // The space-separated `Display` form is rejected, only `T` is accepted.
        assert!(
            serde_json::from_str::<TimeParam>(r#"{"created_start": "2024-01-01 00:00:00"}"#)
                .is_err()
        );
    }
}