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use cassandra::data_type::ConstDataType;
use cassandra::statement::Statement;
use cassandra::util::Protected;

use cassandra_sys::CassPrepared as _PreparedStatement;
use cassandra_sys::cass_prepared_bind;
use cassandra_sys::cass_prepared_free;
use cassandra_sys::cass_prepared_parameter_data_type;
use cassandra_sys::cass_prepared_parameter_data_type_by_name;
use cassandra_sys::cass_prepared_parameter_name;
use std::{mem, slice, str};
use std::ffi::CString;

/// A statement that has been prepared against at least one Cassandra node.
/// Instances of this class should not be created directly, but through Session.prepare().
#[derive(Debug)]
pub struct PreparedStatement(*const _PreparedStatement);

unsafe impl Sync for PreparedStatement {}
unsafe impl Send for PreparedStatement {}

impl Drop for PreparedStatement {
    /// Frees a prepared statement
    fn drop(&mut self) {
        if !self.0.is_null() {
            unsafe { cass_prepared_free(self.0) }
        }
    }
}


impl Protected<*const _PreparedStatement> for PreparedStatement {
    fn inner(&self) -> *const _PreparedStatement { self.0 }
    fn build(inner: *const _PreparedStatement) -> Self { PreparedStatement(inner) }
}

impl PreparedStatement {
    /// Creates a bound statement from a pre-prepared statement.
    pub fn bind(&self) -> Statement { unsafe { Statement::build(cass_prepared_bind(self.0)) } }

    /// Gets the name of a parameter at the specified index.
    #[allow(cast_possible_truncation)]
    pub fn parameter_name(&self, index: usize) -> Result<&str, str::Utf8Error> {
        unsafe {
            let mut name = mem::zeroed();
            let mut name_length = mem::zeroed();
            cass_prepared_parameter_name(self.0, index, &mut name, &mut name_length);
            str::from_utf8(slice::from_raw_parts(name as *const u8, name_length as usize))
        }
    }

    /// Gets the data type of a parameter at the specified index.
    ///
    /// Returns a reference to the data type of the parameter. Do not free
    /// this reference as it is bound to the lifetime of the prepared.
    pub fn parameter_data_type(&self, index: usize) -> ConstDataType {
        unsafe { ConstDataType(cass_prepared_parameter_data_type(self.0, index)) }
    }

    /// Gets the data type of a parameter for the specified name.
    ///
    /// Returns a reference to the data type of the parameter. Do not free
    /// this reference as it is bound to the lifetime of the prepared.
    pub fn parameter_data_type_by_name(&self, name: &str) -> ConstDataType {
        unsafe {
            ConstDataType(cass_prepared_parameter_data_type_by_name(self.0,
                                                                    CString::new(name)
                                                                        .expect("must be utf8")
                                                                        .as_ptr()))
        }
    }
}