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use crate::cassandra::error::*;
use crate::cassandra::statement::Statement;
use crate::cassandra::util::{Protected, ProtectedInner, ProtectedWithSession};
use crate::{cassandra::data_type::ConstDataType, session_scope, Session};

use crate::cassandra_sys::cass_prepared_bind;
use crate::cassandra_sys::cass_prepared_free;
use crate::cassandra_sys::cass_prepared_parameter_data_type;
use crate::cassandra_sys::cass_prepared_parameter_data_type_by_name_n;
use crate::cassandra_sys::cass_prepared_parameter_name;
use crate::cassandra_sys::CassPrepared as _PreparedStatement;
use std::os::raw::c_char;
use std::{mem, slice, str};

/// 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<T = session_scope::Bound>(*const _PreparedStatement, Session<T>);

unsafe impl<T: Send> Send for PreparedStatement<T> {}
unsafe impl<T: Sync> Sync for PreparedStatement<T> {}

impl<T> Drop for PreparedStatement<T> {
    /// Frees a prepared statement
    fn drop(&mut self) {
        unsafe { cass_prepared_free(self.0) }
    }
}

impl<T> ProtectedInner<*const _PreparedStatement> for PreparedStatement<T> {
    #[inline(always)]
    fn inner(&self) -> *const _PreparedStatement {
        self.0
    }
}

impl<T> ProtectedWithSession<*const _PreparedStatement, T> for PreparedStatement<T> {
    #[inline(always)]
    fn build(inner: *const _PreparedStatement, session: Session<T>) -> Self {
        if inner.is_null() {
            panic!("Unexpected null pointer")
        };
        PreparedStatement(inner, session)
    }

    #[inline(always)]
    fn session(&self) -> &Session<T> {
        &self.1
    }
}

impl<T: Clone> PreparedStatement<T> {
    /// Creates a bound statement from a pre-prepared statement.
    pub fn bind(&self) -> Statement<T> {
        unsafe { Statement::build(cass_prepared_bind(self.inner()), self.session().clone()) }
    }

    /// Returns the session of which this prepared statement is bound to.
    pub fn session(&self) -> &Session<T> {
        ProtectedWithSession::session(self)
    }

    /// Gets the name of a parameter at the specified index.
    pub fn parameter_name(&self, index: usize) -> Result<&str> {
        unsafe {
            let mut name = mem::zeroed();
            let mut name_length = mem::zeroed();
            cass_prepared_parameter_name(self.0, index, &mut name, &mut name_length)
                .to_result(())
                .and_then(|_| {
                    Ok(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) -> Option<ConstDataType> {
        unsafe {
            let inner = cass_prepared_parameter_data_type(self.0, index);
            if inner.is_null() {
                None
            } else {
                Some(ConstDataType::build(inner))
            }
        }
    }

    /// 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) -> Option<ConstDataType> {
        unsafe {
            let name_ptr = name.as_ptr() as *const c_char;
            let inner = cass_prepared_parameter_data_type_by_name_n(self.0, name_ptr, name.len());
            if inner.is_null() {
                None
            } else {
                Some(ConstDataType::build(inner))
            }
        }
    }
}