#[derive(Debug)]
pub struct Pager<E: crate::Entity> {
rows: crate::Rows<E>,
count: usize,
page: usize,
max_per_page: usize,
}
impl<E: crate::Entity> Pager<E> {
pub fn new(rows: crate::Rows<E>, count: usize, page: usize, max_per_page: usize) -> Self {
Self {
rows,
count,
page,
max_per_page,
}
}
pub fn result_count(&self) -> usize {
self.rows.len()
}
pub fn result_min(&self) -> usize {
usize::min(1 + self.max_per_page * (self.page - 1), self.count)
}
pub fn result_max(&self) -> usize {
(self.page - 1) * self.max_per_page + self.result_count()
}
pub fn last_page(&self) -> usize {
if self.count == 0 {
1
} else {
(self.count as f32 / self.max_per_page as f32).ceil() as usize
}
}
pub fn page(&self) -> usize {
self.page
}
pub fn has_next_page(&self) -> bool {
self.page < self.last_page()
}
pub fn has_previous_page(&self) -> bool {
self.page > 1
}
pub fn count(&self) -> usize {
self.count
}
pub fn max_per_page(&self) -> usize {
self.max_per_page
}
pub fn rows(&self) -> &crate::Rows<E> {
&self.rows
}
}
impl<E: crate::Entity> std::iter::IntoIterator for Pager<E> {
type IntoIter = crate::Rows<Self::Item>;
type Item = E;
fn into_iter(self) -> Self::IntoIter {
self.rows
}
}
#[cfg(feature = "serde")]
impl<E: crate::Entity + serde::Serialize> serde::Serialize for Pager<E> {
fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
where
S: serde::Serializer,
{
use serde::ser::SerializeStruct;
let mut state = serializer.serialize_struct("Pager", 10)?;
state.serialize_field("result_count", &self.result_count())?;
state.serialize_field("result_min", &self.result_min())?;
state.serialize_field("result_max", &self.result_max())?;
state.serialize_field("last_page", &self.last_page())?;
state.serialize_field("page", &self.page())?;
state.serialize_field("has_next_page", &self.has_next_page())?;
state.serialize_field("has_previous_page", &self.has_previous_page())?;
state.serialize_field("count", &self.count())?;
state.serialize_field("max_per_page", &self.max_per_page())?;
state.serialize_field("iterator", &self.rows)?;
state.end()
}
}