use serde::{Deserialize, Serialize};
use crate::{ModuleId, Span, VarId};
use std::collections::HashSet;
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub enum ImportPatternMember {
    Glob { span: Span },
    Name { name: Vec<u8>, span: Span },
    List { names: Vec<(Vec<u8>, Span)> },
}
impl ImportPatternMember {
    pub fn span(&self) -> Span {
        match self {
            ImportPatternMember::Glob { span } | ImportPatternMember::Name { span, .. } => *span,
            ImportPatternMember::List { names } => {
                let first = names
                    .first()
                    .map(|&(_, span)| span)
                    .unwrap_or(Span::unknown());
                let last = names
                    .last()
                    .map(|&(_, span)| span)
                    .unwrap_or(Span::unknown());
                Span::append(first, last)
            }
        }
    }
}
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub struct ImportPatternHead {
    pub name: Vec<u8>,
    pub id: Option<ModuleId>,
    pub span: Span,
}
#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
pub struct ImportPattern {
    pub head: ImportPatternHead,
    pub members: Vec<ImportPatternMember>,
    pub hidden: HashSet<Vec<u8>>,
    pub constants: Vec<VarId>,
}
impl ImportPattern {
    pub fn new() -> Self {
        ImportPattern {
            head: ImportPatternHead {
                name: vec![],
                id: None,
                span: Span::unknown(),
            },
            members: vec![],
            hidden: HashSet::new(),
            constants: vec![],
        }
    }
    pub fn span(&self) -> Span {
        Span::append(
            self.head.span,
            self.members
                .last()
                .map(ImportPatternMember::span)
                .unwrap_or(self.head.span),
        )
    }
    pub fn with_hidden(self, hidden: HashSet<Vec<u8>>) -> Self {
        ImportPattern {
            head: self.head,
            members: self.members,
            hidden,
            constants: self.constants,
        }
    }
}
impl Default for ImportPattern {
    fn default() -> Self {
        Self::new()
    }
}