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use super::*;
use serde_json;
use std;

#[derive(Clone, Debug, Deserialize, PartialEq, PartialOrd, Serialize)]
pub enum SymbolicConstraint {
    Eq { v1: String, v2: String },
    Neq { v1: String, v2: String },
}

impl std::fmt::Display for SymbolicConstraint {
    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
        write!(f, "{}", serde_json::to_string(&self).unwrap())
    }
}

impl SymbolicConstraint {
    /// Try to solve this constraint using the information in the bindings
    pub fn solve<T: ConstraintValue>(&self, bindings: &Bindings<T>) -> SolveResult<T> {
        match *self {
                SymbolicConstraint::Eq { ref v1, ref v2 } => {
                    println!("\n{:?}\n{:?}\n{:?}",
                             bindings.get_binding(v1),
                             bindings.get_binding(v2),
                             T::variable(v1).and_then(|var1| Some(SolveResult::Partial(bindings.set_binding(v2, var1)))));
                    match (bindings.get_binding(v1), bindings.get_binding(v2)) {
                        (Some(ref val1), Some(ref val2)) => {
                            if val1.eq(val2) {
                                Some(SolveResult::Success(bindings.clone()))
                            } else {
                                None
                            }
                        }
                        _ => Some(SolveResult::Partial(bindings.clone())),
                    }
                }
                SymbolicConstraint::Neq { ref v1, ref v2 } => {
                    match (bindings.get_binding(v1), bindings.get_binding(v2)) {
                        (Some(ref val1), Some(ref val2)) => {
                            if val1.eq(val2) {
                                None
                            } else {
                                Some(SolveResult::Success(bindings.clone()))
                            }
                        }
                        _ => Some(SolveResult::Partial(bindings.clone())),
                    }
                }
            }
            .unwrap_or(SolveResult::Conflict)
    }

    pub fn rename_variables(&self, renamed_variables: &HashMap<String, String>) -> Self {
        let lookup = |v: &String| -> String { renamed_variables.get(v).cloned().or_else(|| Some(v.clone())).unwrap() };
        match *self {
            SymbolicConstraint::Eq { ref v1, ref v2 } => {
                SymbolicConstraint::Eq {
                    v1: lookup(v1),
                    v2: lookup(v2),
                }
            }
            SymbolicConstraint::Neq { ref v1, ref v2 } => {
                SymbolicConstraint::Neq {
                    v1: lookup(v1),
                    v2: lookup(v2),
                }
            }
        }
    }

    pub fn variables(&self) -> Vec<String> {
        match *self {
            SymbolicConstraint::Eq { ref v1, ref v2 } => vec![v1.clone(), v2.clone()],
            SymbolicConstraint::Neq { ref v1, ref v2 } => vec![v1.clone(), v2.clone()],
        }
    }
}