use Context;
use EmptyContext;
use EvalexprError;
use EvalexprResult;
use FloatType;
use IntType;
use Node;
use token;
use tree;
use Value;
use value::TupleType;

/// Evaluate the given expression string.
///
/// # Examples
///
/// ```rust
/// use evalexpr::*;
///
/// assert_eq!(eval("1 + 2 + 3"), Ok(Value::from(6)));
/// ```
///
/// *See the [crate doc](index.html) for more examples and explanations of the expression format.*
pub fn eval(string: &str) -> EvalexprResult<Value> {
    eval_with_context(string, &EmptyContext)
}

/// Evaluate the given expression string with the given context.
///
/// # Examples
///
/// ```rust
/// use evalexpr::*;
///
/// let mut context = HashMapContext::new();
/// context.set_value("one".into(), 1.into()).unwrap(); // Do proper error handling here
/// context.set_value("two".into(), 2.into()).unwrap(); // Do proper error handling here
/// context.set_value("three".into(), 3.into()).unwrap(); // Do proper error handling here
/// assert_eq!(eval_with_context("one + two + three", &context), Ok(Value::from(6)));
/// ```
///
/// *See the [crate doc](index.html) for more examples and explanations of the expression format.*
pub fn eval_with_context(string: &str, context: &Context) -> EvalexprResult<Value> {
    tree::tokens_to_operator_tree(token::tokenize(string)?)?.eval_with_context(context)
}

/// Build the operator tree for the given expression string.
///
/// The operator tree can later on be evaluated directly.
/// This saves runtime if a single expression should be evaluated multiple times, for example with differing contexts.
///
/// # Examples
///
/// ```rust
/// use evalexpr::*;
///
/// let precomputed = build_operator_tree("one + two + three").unwrap(); // Do proper error handling here
///
/// let mut context = HashMapContext::new();
/// context.set_value("one".into(), 1.into()).unwrap(); // Do proper error handling here
/// context.set_value("two".into(), 2.into()).unwrap(); // Do proper error handling here
/// context.set_value("three".into(), 3.into()).unwrap(); // Do proper error handling here
///
/// assert_eq!(precomputed.eval_with_context(&context), Ok(Value::from(6)));
///
/// context.set_value("three".into(), 5.into()).unwrap(); // Do proper error handling here
/// assert_eq!(precomputed.eval_with_context(&context), Ok(Value::from(8)));
/// ```
///
/// *See the [crate doc](index.html) for more examples and explanations of the expression format.*
pub fn build_operator_tree(string: &str) -> EvalexprResult<Node> {
    tree::tokens_to_operator_tree(token::tokenize(string)?)
}

/// Evaluate the given expression string into a string.
///
/// *See the [crate doc](index.html) for more examples and explanations of the expression format.*
pub fn eval_string(string: &str) -> EvalexprResult<String> {
    match eval(string) {
        Ok(Value::String(string)) => Ok(string),
        Ok(value) => Err(EvalexprError::expected_string(value)),
        Err(error) => Err(error),
    }
}

/// Evaluate the given expression string into an integer.
///
/// *See the [crate doc](index.html) for more examples and explanations of the expression format.*
pub fn eval_int(string: &str) -> EvalexprResult<IntType> {
    match eval(string) {
        Ok(Value::Int(int)) => Ok(int),
        Ok(value) => Err(EvalexprError::expected_int(value)),
        Err(error) => Err(error),
    }
}

/// Evaluate the given expression string into a float.
///
/// *See the [crate doc](index.html) for more examples and explanations of the expression format.*
pub fn eval_float(string: &str) -> EvalexprResult<FloatType> {
    match eval(string) {
        Ok(Value::Float(float)) => Ok(float),
        Ok(value) => Err(EvalexprError::expected_float(value)),
        Err(error) => Err(error),
    }
}

/// Evaluate the given expression string into a float.
/// If the result of the expression is an integer, it is silently converted into a float.
///
/// *See the [crate doc](index.html) for more examples and explanations of the expression format.*
pub fn eval_number(string: &str) -> EvalexprResult<FloatType> {
    match eval(string) {
        Ok(Value::Float(float)) => Ok(float),
        Ok(Value::Int(int)) => Ok(int as FloatType),
        Ok(value) => Err(EvalexprError::expected_float(value)),
        Err(error) => Err(error),
    }
}

/// Evaluate the given expression string into a boolean.
///
/// *See the [crate doc](index.html) for more examples and explanations of the expression format.*
pub fn eval_boolean(string: &str) -> EvalexprResult<bool> {
    match eval(string) {
        Ok(Value::Boolean(boolean)) => Ok(boolean),
        Ok(value) => Err(EvalexprError::expected_boolean(value)),
        Err(error) => Err(error),
    }
}

/// Evaluate the given expression string into a tuple.
///
/// *See the [crate doc](index.html) for more examples and explanations of the expression format.*
pub fn eval_tuple(string: &str) -> EvalexprResult<TupleType> {
    match eval(string) {
        Ok(Value::Tuple(tuple)) => Ok(tuple),
        Ok(value) => Err(EvalexprError::expected_tuple(value)),
        Err(error) => Err(error),
    }
}

/// Evaluate the given expression string into a string with the given context.
///
/// *See the [crate doc](index.html) for more examples and explanations of the expression format.*
pub fn eval_string_with_context(string: &str, context: &Context) -> EvalexprResult<String> {
    match eval_with_context(string, context) {
        Ok(Value::String(string)) => Ok(string),
        Ok(value) => Err(EvalexprError::expected_string(value)),
        Err(error) => Err(error),
    }
}

/// Evaluate the given expression string into an integer with the given context.
///
/// *See the [crate doc](index.html) for more examples and explanations of the expression format.*
pub fn eval_int_with_context(string: &str, context: &Context) -> EvalexprResult<IntType> {
    match eval_with_context(string, context) {
        Ok(Value::Int(int)) => Ok(int),
        Ok(value) => Err(EvalexprError::expected_int(value)),
        Err(error) => Err(error),
    }
}

/// Evaluate the given expression string into a float with the given context.
///
/// *See the [crate doc](index.html) for more examples and explanations of the expression format.*
pub fn eval_float_with_context(string: &str, context: &Context) -> EvalexprResult<FloatType> {
    match eval_with_context(string, context) {
        Ok(Value::Float(float)) => Ok(float),
        Ok(value) => Err(EvalexprError::expected_float(value)),
        Err(error) => Err(error),
    }
}

/// Evaluate the given expression string into a float with the given context.
/// If the result of the expression is an integer, it is silently converted into a float.
///
/// *See the [crate doc](index.html) for more examples and explanations of the expression format.*
pub fn eval_number_with_context(string: &str, context: &Context) -> EvalexprResult<FloatType> {
    match eval_with_context(string, context) {
        Ok(Value::Float(float)) => Ok(float),
        Ok(Value::Int(int)) => Ok(int as FloatType),
        Ok(value) => Err(EvalexprError::expected_float(value)),
        Err(error) => Err(error),
    }
}

/// Evaluate the given expression string into a boolean with the given context.
///
/// *See the [crate doc](index.html) for more examples and explanations of the expression format.*
pub fn eval_boolean_with_context(string: &str, context: &Context) -> EvalexprResult<bool> {
    match eval_with_context(string, context) {
        Ok(Value::Boolean(boolean)) => Ok(boolean),
        Ok(value) => Err(EvalexprError::expected_boolean(value)),
        Err(error) => Err(error),
    }
}

/// Evaluate the given expression string into a tuple with the given context.
///
/// *See the [crate doc](index.html) for more examples and explanations of the expression format.*
pub fn eval_tuple_with_context(string: &str, context: &Context) -> EvalexprResult<TupleType> {
    match eval_with_context(string, context) {
        Ok(Value::Tuple(tuple)) => Ok(tuple),
        Ok(value) => Err(EvalexprError::expected_tuple(value)),
        Err(error) => Err(error),
    }
}