diesel 2.4.0

use crate::mysql_like::MysqlLikeBackend;
use crate::query_builder::limit_clause::{LimitClause, NoLimitClause};
use crate::query_builder::limit_offset_clause::{
    BoxedCloneLimitOffsetClause, BoxedLimitOffsetClause, LimitOffsetClause,
};
use crate::query_builder::offset_clause::{NoOffsetClause, OffsetClause};
use crate::query_builder::{AstPass, IntoBoxedClause, IntoBoxedCloneClause, QueryFragment};
use crate::result::QueryResult;
use alloc::sync::Arc;

//#[diagnostic::do_not_recommend]
impl<DB: MysqlLikeBackend> QueryFragment<DB> for LimitOffsetClause<NoLimitClause, NoOffsetClause> {
    fn walk_ast<'b>(&'b self, _out: AstPass<'_, 'b, DB>) -> QueryResult<()> {
        Ok(())
    }
}

//#[diagnostic::do_not_recommend]
impl<DB: MysqlLikeBackend, L> QueryFragment<DB>
    for LimitOffsetClause<LimitClause<L>, NoOffsetClause>
where
    LimitClause<L>: QueryFragment<DB>,
{
    fn walk_ast<'b>(&'b self, out: AstPass<'_, 'b, DB>) -> QueryResult<()> {
        self.limit_clause.walk_ast(out)?;
        Ok(())
    }
}

//#[diagnostic::do_not_recommend]
impl<DB: MysqlLikeBackend, L, O> QueryFragment<DB>
    for LimitOffsetClause<LimitClause<L>, OffsetClause<O>>
where
    LimitClause<L>: QueryFragment<DB>,
    OffsetClause<O>: QueryFragment<DB>,
{
    fn walk_ast<'b>(&'b self, mut out: AstPass<'_, 'b, DB>) -> QueryResult<()> {
        self.limit_clause.walk_ast(out.reborrow())?;
        self.offset_clause.walk_ast(out.reborrow())?;
        Ok(())
    }
}

/// Walk the limit and the offset of a boxed limit/offset clause, whichever pointer holds them.
fn walk_boxed_limit_offset<'b, DB, P>(
    limit: Option<&'b P>,
    offset: Option<&'b P>,
    mut out: AstPass<'_, 'b, DB>,
) -> QueryResult<()>
where
    DB: MysqlLikeBackend,
    P: QueryFragment<DB>,
{
    match (limit, offset) {
        (Some(limit), Some(offset)) => {
            limit.walk_ast(out.reborrow())?;
            offset.walk_ast(out.reborrow())?;
        }
        (Some(limit), None) => {
            limit.walk_ast(out.reborrow())?;
        }
        (None, Some(offset)) => {
            // Mysql requires a limit clause in front of any offset clause
            // The documentation proposes the following:
            // > To retrieve all rows from a certain offset up to the end of the
            // > result set, you can use some large number for the second parameter.
            // https://dev.mysql.com/doc/refman/8.0/en/select.html
            // Therefore we just use u64::MAX as limit here
            // That does not result in any limitations because Mysql only supports
            // up to 64TB of data per table. Assuming 1 bit per row this means
            // 1024 * 1024 * 1024 * 1024 * 8 = 562.949.953.421.312 rows which is smaller
            // than 2^64 = 18.446.744.073.709.551.615
            out.push_sql(" LIMIT 18446744073709551615 ");
            offset.walk_ast(out.reborrow())?;
        }
        (None, None) => {}
    }
    Ok(())
}

#[diagnostic::do_not_recommend]
impl<DB: MysqlLikeBackend> QueryFragment<DB> for BoxedLimitOffsetClause<'_, DB> {
    fn walk_ast<'b>(&'b self, out: AstPass<'_, 'b, DB>) -> QueryResult<()> {
        walk_boxed_limit_offset(self.limit.as_ref(), self.offset.as_ref(), out)
    }
}

#[diagnostic::do_not_recommend]
impl<'a, DB: MysqlLikeBackend> IntoBoxedClause<'a, DB>
    for LimitOffsetClause<NoLimitClause, NoOffsetClause>
{
    type BoxedClause = BoxedLimitOffsetClause<'a, DB>;

    fn into_boxed(self) -> Self::BoxedClause {
        BoxedLimitOffsetClause {
            limit: None,
            offset: None,
        }
    }
}

#[diagnostic::do_not_recommend]
impl<'a, DB: MysqlLikeBackend, L> IntoBoxedClause<'a, DB>
    for LimitOffsetClause<LimitClause<L>, NoOffsetClause>
where
    L: QueryFragment<DB> + Send + 'a,
{
    type BoxedClause = BoxedLimitOffsetClause<'a, DB>;

    fn into_boxed(self) -> Self::BoxedClause {
        BoxedLimitOffsetClause {
            limit: Some(Box::new(self.limit_clause)),
            offset: None,
        }
    }
}

#[diagnostic::do_not_recommend]
impl<'a, DB: MysqlLikeBackend, L, O> IntoBoxedClause<'a, DB>
    for LimitOffsetClause<LimitClause<L>, OffsetClause<O>>
where
    L: QueryFragment<DB> + Send + 'a,
    O: QueryFragment<DB> + Send + 'a,
{
    type BoxedClause = BoxedLimitOffsetClause<'a, DB>;

    fn into_boxed(self) -> Self::BoxedClause {
        BoxedLimitOffsetClause {
            limit: Some(Box::new(self.limit_clause)),
            offset: Some(Box::new(self.offset_clause)),
        }
    }
}

impl<DB: MysqlLikeBackend> QueryFragment<DB> for BoxedCloneLimitOffsetClause<'_, DB> {
    fn walk_ast<'b>(&'b self, out: AstPass<'_, 'b, DB>) -> QueryResult<()> {
        walk_boxed_limit_offset(self.limit.as_ref(), self.offset.as_ref(), out)
    }
}

impl<'a, DB: MysqlLikeBackend> IntoBoxedCloneClause<'a, DB>
    for LimitOffsetClause<NoLimitClause, NoOffsetClause>
{
    type BoxedCloneClause = BoxedCloneLimitOffsetClause<'a, DB>;

    fn into_boxed_clone(self) -> Self::BoxedCloneClause {
        BoxedCloneLimitOffsetClause {
            limit: None,
            offset: None,
        }
    }
}

impl<'a, DB: MysqlLikeBackend, L> IntoBoxedCloneClause<'a, DB>
    for LimitOffsetClause<LimitClause<L>, NoOffsetClause>
where
    L: QueryFragment<DB> + Send + Sync + 'a,
{
    type BoxedCloneClause = BoxedCloneLimitOffsetClause<'a, DB>;

    fn into_boxed_clone(self) -> Self::BoxedCloneClause {
        BoxedCloneLimitOffsetClause {
            limit: Some(Arc::new(self.limit_clause)),
            offset: None,
        }
    }
}

impl<'a, DB: MysqlLikeBackend, L, O> IntoBoxedCloneClause<'a, DB>
    for LimitOffsetClause<LimitClause<L>, OffsetClause<O>>
where
    L: QueryFragment<DB> + Send + Sync + 'a,
    O: QueryFragment<DB> + Send + Sync + 'a,
{
    type BoxedCloneClause = BoxedCloneLimitOffsetClause<'a, DB>;

    fn into_boxed_clone(self) -> Self::BoxedCloneClause {
        BoxedCloneLimitOffsetClause {
            limit: Some(Arc::new(self.limit_clause)),
            offset: Some(Arc::new(self.offset_clause)),
        }
    }
}