deser-value 0.10.1

use std::fmt;
use std::hash::{Hash, Hasher};
use std::ops::{Deref, DerefMut};

use deser_core::Order;

use crate::tree;
use crate::value::{Kind, Value};

/// A sequence of values.
///
/// A sequence dereferences to a [`Vec`] of its values.  Additionally it
/// holds the [`Order`] of the values, which is passed on when the sequence
/// is serialized, if it holds the values of a repeated key of a multimap
/// (see [`Map::is_multimap`](crate::Map::is_multimap)) and if an empty
/// sequence could also be an empty map (see
/// [`is_ambiguous_empty`](Self::is_ambiguous_empty)).  They are not
/// considered when sequences are compared.
///
/// ```
/// use deser::Order;
/// use deser_value::{Seq, Value};
///
/// let mut seq = Seq::new();
/// seq.set_order(Order::Sorted);
/// seq.push(Value::from(1));
/// seq.push(Value::from(2));
/// assert_eq!(seq.len(), 2);
/// assert_eq!(seq.order(), Order::Sorted);
/// ```
#[derive(Default)]
pub struct Seq {
    pub(crate) items: Vec<Value>,
    pub(crate) order: Order,
    pub(crate) repeated: bool,
    pub(crate) ambiguous_empty: bool,
}

impl Seq {
    /// Creates an empty sequence.
    pub const fn new() -> Seq {
        Seq {
            items: Vec::new(),
            order: Order::Natural,
            repeated: false,
            ambiguous_empty: false,
        }
    }

    /// Creates an empty sequence with a capacity.
    pub fn with_capacity(capacity: usize) -> Seq {
        Seq {
            items: Vec::with_capacity(capacity),
            order: Order::Natural,
            repeated: false,
            ambiguous_empty: false,
        }
    }

    /// Returns the order of the values.
    pub fn order(&self) -> Order {
        self.order
    }

    /// Sets the order of the values.
    pub fn set_order(&mut self, order: Order) {
        self.order = order;
    }

    /// Returns `true` if the sequence holds the values of a repeated key.
    ///
    /// Within a multimap (see [`Map::is_multimap`](crate::Map::is_multimap))
    /// the values are passed on as the values of a key that is given more
    /// than once.  Elsewhere this has no effect.
    pub fn is_repeated(&self) -> bool {
        self.repeated
    }

    /// Sets if the sequence holds the values of a repeated key.
    pub fn set_repeated(&mut self, yes: bool) {
        self.repeated = yes;
    }

    /// Returns `true` if the sequence is empty and could also be an empty
    /// map.
    ///
    /// Sequences that are deserialized from empty containers that formats
    /// cannot tell apart from empty maps (like the empty arrays of PHP, see
    /// [`ContainerShape::set_ambiguous_empty`](deser_core::ContainerShape::set_ambiguous_empty))
    /// are marked like this.  When the sequence is deserialized into
    /// another type, types that expect a map receive an empty map, and an
    /// update of a map with it leaves the map as it is.  The flag has no
    /// effect once the sequence has values.
    ///
    /// ```
    /// use std::collections::BTreeMap;
    /// use deser_value::{Seq, Value};
    ///
    /// let mut seq = Seq::new();
    /// seq.set_ambiguous_empty(true);
    /// let map: BTreeMap<String, u32> = deser_value::from_value(&Value::from(seq)).unwrap();
    /// assert!(map.is_empty());
    /// ```
    pub fn is_ambiguous_empty(&self) -> bool {
        self.ambiguous_empty && self.items.is_empty()
    }

    /// Sets if the sequence could also be an empty map when it's empty.
    pub fn set_ambiguous_empty(&mut self, yes: bool) {
        self.ambiguous_empty = yes;
    }

    /// Creates an empty sequence with the order and the flags of this one.
    pub(crate) fn empty_like(&self, capacity: usize) -> Seq {
        let mut seq = Seq::with_capacity(capacity);
        seq.set_order(self.order);
        seq.set_repeated(self.repeated);
        seq.set_ambiguous_empty(self.ambiguous_empty);
        seq
    }

    /// Converts the sequence into a vector.
    pub fn into_vec(mut self) -> Vec<Value> {
        std::mem::take(&mut self.items)
    }
}

impl Deref for Seq {
    type Target = Vec<Value>;

    fn deref(&self) -> &Vec<Value> {
        &self.items
    }
}

impl DerefMut for Seq {
    fn deref_mut(&mut self) -> &mut Vec<Value> {
        &mut self.items
    }
}

impl Drop for Seq {
    fn drop(&mut self) {
        if self.items.iter().any(|item| item.has_children()) {
            tree::drop_values(std::mem::take(&mut self.items));
        }
    }
}

impl Clone for Seq {
    fn clone(&self) -> Seq {
        match tree::clone_seq(self) {
            Kind::Seq(seq) => seq,
            _ => unreachable!(),
        }
    }
}

impl PartialEq for Seq {
    fn eq(&self, other: &Seq) -> bool {
        tree::eq_seq(self, other)
    }
}

impl Eq for Seq {}

impl Hash for Seq {
    fn hash<H: Hasher>(&self, state: &mut H) {
        tree::hash_seq(self, state);
    }
}

impl fmt::Debug for Seq {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        tree::fmt_seq(self, f)
    }
}

impl From<Vec<Value>> for Seq {
    fn from(items: Vec<Value>) -> Seq {
        Seq {
            items,
            order: Order::Natural,
            repeated: false,
            ambiguous_empty: false,
        }
    }
}

impl From<Seq> for Vec<Value> {
    fn from(seq: Seq) -> Vec<Value> {
        seq.into_vec()
    }
}

impl<T: Into<Value>> FromIterator<T> for Seq {
    fn from_iter<I: IntoIterator<Item = T>>(iter: I) -> Seq {
        Seq::from(iter.into_iter().map(Into::into).collect::<Vec<_>>())
    }
}

impl<T: Into<Value>> Extend<T> for Seq {
    fn extend<I: IntoIterator<Item = T>>(&mut self, iter: I) {
        self.items.extend(iter.into_iter().map(Into::into));
    }
}

impl IntoIterator for Seq {
    type Item = Value;
    type IntoIter = std::vec::IntoIter<Value>;

    fn into_iter(self) -> Self::IntoIter {
        self.into_vec().into_iter()
    }
}

impl<'a> IntoIterator for &'a Seq {
    type Item = &'a Value;
    type IntoIter = std::slice::Iter<'a, Value>;

    fn into_iter(self) -> Self::IntoIter {
        self.items.iter()
    }
}

impl<'a> IntoIterator for &'a mut Seq {
    type Item = &'a mut Value;
    type IntoIter = std::slice::IterMut<'a, Value>;

    fn into_iter(self) -> Self::IntoIter {
        self.items.iter_mut()
    }
}