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//! Switch node.
//!
use crate::syntax::ast::node::Node;
use boa_gc::{Finalize, Trace};
use boa_interner::{Interner, ToInternedString};

use crate::syntax::ast::node::StatementList;

#[cfg(feature = "deser")]
use serde::{Deserialize, Serialize};

#[cfg(test)]
mod tests;

#[cfg_attr(feature = "deser", derive(Serialize, Deserialize))]
#[derive(Clone, Debug, Trace, Finalize, PartialEq)]
pub struct Case {
    condition: Node,
    body: StatementList,
}

impl Case {
    /// Creates a `Case` AST node.
    pub fn new<C, B>(condition: C, body: B) -> Self
    where
        C: Into<Node>,
        B: Into<StatementList>,
    {
        Self {
            condition: condition.into(),
            body: body.into(),
        }
    }

    /// Gets the condition of the case.
    pub fn condition(&self) -> &Node {
        &self.condition
    }

    /// Gets the statement listin the body of the case.
    pub fn body(&self) -> &StatementList {
        &self.body
    }
}

/// The `switch` statement evaluates an expression, matching the expression's value to a case
/// clause, and executes statements associated with that case, as well as statements in cases
/// that follow the matching case.
///
/// A `switch` statement first evaluates its expression. It then looks for the first case
/// clause whose expression evaluates to the same value as the result of the input expression
/// (using the strict comparison, `===`) and transfers control to that clause, executing the
/// associated statements. (If multiple cases match the provided value, the first case that
/// matches is selected, even if the cases are not equal to each other.)
///
/// More information:
///  - [ECMAScript reference][spec]
///  - [MDN documentation][mdn]
///
/// [spec]: https://tc39.es/ecma262/#prod-SwitchStatement
/// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/switch
#[cfg_attr(feature = "deser", derive(Serialize, Deserialize))]
#[derive(Clone, Debug, Trace, Finalize, PartialEq)]
pub struct Switch {
    val: Box<Node>,
    cases: Box<[Case]>,
    default: Option<StatementList>,
}

impl Switch {
    /// Creates a `Switch` AST node.
    pub fn new<V, C, D>(val: V, cases: C, default: Option<D>) -> Self
    where
        V: Into<Node>,
        C: Into<Box<[Case]>>,
        D: Into<StatementList>,
    {
        Self {
            val: Box::new(val.into()),
            cases: cases.into(),
            default: default.map(D::into),
        }
    }

    /// Gets the value to switch.
    pub fn val(&self) -> &Node {
        &self.val
    }

    /// Gets the list of cases for the switch statement.
    pub fn cases(&self) -> &[Case] {
        &self.cases
    }

    /// Gets the default statement list, if any.
    pub fn default(&self) -> Option<&[Node]> {
        self.default.as_ref().map(StatementList::items)
    }

    /// Implements the display formatting with indentation.
    pub(in crate::syntax::ast::node) fn to_indented_string(
        &self,
        interner: &Interner,
        indentation: usize,
    ) -> String {
        let indent = "    ".repeat(indentation);
        let mut buf = format!("switch ({}) {{\n", self.val().to_interned_string(interner));
        for e in self.cases().iter() {
            buf.push_str(&format!(
                "{}    case {}:\n{}",
                indent,
                e.condition().to_interned_string(interner),
                e.body().to_indented_string(interner, indentation + 2)
            ));
        }

        if let Some(ref default) = self.default {
            buf.push_str(&format!(
                "{indent}    default:\n{}",
                default.to_indented_string(interner, indentation + 2)
            ));
        }
        buf.push_str(&format!("{indent}}}"));

        buf
    }
}

impl ToInternedString for Switch {
    fn to_interned_string(&self, interner: &Interner) -> String {
        self.to_indented_string(interner, 0)
    }
}

impl From<Switch> for Node {
    fn from(switch: Switch) -> Self {
        Self::Switch(switch)
    }
}