advotracker_db/src/models/traits/trait.rs

// SPDX-License-Identifier: (0BSD or MIT)
/*
 * advotracker - Hotline tackingtool for Advocats
 *
 * Copyright 2020-2021 Ralf Zerres <ralf.zerres@networkx.de>
 */

// bring models into scope
use diesel::backend::Backend;
use diesel::deserialize;
use diesel::deserialize::FromSql;
use diesel::serialize;
use diesel::serialize::{Output, ToSql};
use diesel::sql_types::Integer;
//use serde::Serializer;
use serde;

//use super::models::ConfirmState;
//use crate::db::models::ConfirmState;

// trait: meaningful enum/types for email confirmation states
// in analogy: https://noyez.gitlab.io/post/2018-08-05-a-small-custom-bool-type-in-diesel/

//#[repr(i32)]
#[derive(AsExpression, Copy, Clone, Debug, PartialEq, FromSqlRow)]
#[sql_type = "Integer"]
pub enum ConfirmState {
    Unconfirmed = 0,
    Confirmed = 1,
    Authorized = 2,
    Blocked = 3,
}

impl<DB> ToSql<Integer, DB> for ConfirmState
where
    DB: Backend,
    i32: ToSql<Integer, DB>,
{
    fn to_sql<W: std::io::Write>(&self, out: &mut Output<W, DB>) -> serialize::Result {
        let int_value;
        match &self {
            ConfirmState::Unconfirmed => int_value = 0,
            ConfirmState::Confirmed => int_value = 1,
            ConfirmState::Authorized => int_value = 2,
            ConfirmState::Blocked => int_value = 3,
        }
        println!("Writing to sql: i32:{:?}", &int_value);
        <i32 as ToSql<Integer, DB>>::to_sql(&int_value, out)
    }
}

/*
impl FromSql<Integer, Sqlite>
    for ConfirmState
{
    fn from_sql(
        bytes: Option<&<diesel::sqlite::Sqlite as diesel::backend::Backend>::RawValue>,
    ) -> diesel::deserialize::Result<Self> {
        <i32 as diesel::deserialize::FromSql<
                diesel::sql_types::Integer, diesel::sqlite::Sqlite>>::from_sql()
            .map(ConfirmState::Confirmed)
    }
}
 */

impl<DB> FromSql<Integer, DB> for ConfirmState
where
    DB: Backend<RawValue = [u8]>,
    i32: FromSql<Integer, DB>,
{
    fn from_sql(bytes: Option<&DB::RawValue>) -> deserialize::Result<Self> {
        match <i32 as FromSql<Integer, DB>>::from_sql(bytes)? {
            0 => Ok(ConfirmState::Unconfirmed),
            1 => Ok(ConfirmState::Confirmed),
            2 => Ok(ConfirmState::Authorized),
            3 => Ok(ConfirmState::Blocked),
            x => Err(format!("Unrecognized variant {}", x).into()),
        }
    }
}

/*
// WIP

impl<DB> FromSql<Integer, DB> for ConfirmState
where
    DB: Backend,
    i32: FromSql<Bool, DB> {
    //fn from_sql(bytes: Option<diesel::backend::Backend>::RawValue<DB>) -> diesel::deserialize::Result<Self> {
    fn from_sql(
        bytes: Option<&<DB>::RawValue>,
    ) -> diesel::deserialize::Result<Self> {
        //println!("Reading from sql: bytes:{:?}", bytes);
        match bytes {
            <i32 as diesel::deserialize::FromSql<Integer, DB>>::from_sql(bytes)
                .map(ConfirmState::Confirmed)
        }
        /*
        Some(bytes) => if bytes[0] != 0 {
        Ok(ConfirmState::Confirmed) }
        else { Ok(ConfirmState::Unconfirmed) }
        }
        //<i32 as diesel::deserialize::FromSql<Integer, DB>>::from_sql(bytes).map(ConfirmState::Confirmed)
        //fn from_sql(bytes: Option<Bool>) -> diesel::deserialize::Result<Self> {
        //    println!("Reading from sql: bytes:{:?}", bytes);
        //    match bytes {
        //        Some(bytes) => if bytes[0] != 0 {
        //            Ok(ConfirmState::Confirmed) }
        //        else { Ok(ConfirmState::Unconfirmed) },
        //        None => Ok(ConfirmState::Unconfirmed),
        //    }
         */
    }
}
 */

/*
impl<DB: diesel::backend::Backend<RawValue = [u8]>>
    diesel::deserialize::FromSql<diesel::sql_types::Integer, DB> for ConfirmState
{
    fn from_sql(bytes: Option<&[u8]>) -> diesel::deserialize::Result<Self> {
        <i32 as diesel::deserialize::FromSql<diesel::sql_types::Integer, DB>>::from_sql(
            bytes,
        )
        .map($name)
    }
}
 */

struct ConfirmStateVisitor;
use serde::de::Deserialize;
use serde::de::{self, Visitor};

impl<'de> Visitor<'de> for ConfirmStateVisitor {
    type Value = ConfirmState;

    fn expecting(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
        formatter.write_str("an integer or string of ",
                            "\"Unconfirmed (0)\",",
                            "\"Confirmed (1)\"",
                            "\"Authorized (2)\"",
                            "\"Blocked (3)\".");
    }

    //fn visit_bool<E>(self, value: bool) -> Result<ConfirmState, E>
    //where
    //    E: de::Error,
    //{
    //    match value {
    //        true => Ok(ConfirmState::Confirmed),
    //        false => Ok(ConfirmState::Unconfirmed),
    //    }
    //}

    fn visit_i32<E>(self, value: &'a i32) -> Result<self::Value, E>
    where
        E: de::Error,
    {
        match <i32 as FromSql<Integer, DB>>::from_sql(bytes)? {
            0 => Ok(ConfirmState::Unconfirmed),
            1 => Ok(ConfirmState::Confirmed),
            2 => Ok(ConfirmState::Authorized),
            3 => Ok(ConfirmState::Blocked),
            x => Err(format!("Unrecognized variant {}", x).into()),
            0 => Ok(ConfirmState::Confirmed),
            false => Ok(ConfirmState::Unconfirmed),
        }
    }
    fn visit_str<E>(self, value: &str) -> Result<self::Value, E>
    where
        E: de::Error,
    {
        match value {
            //"Confirmed" | "Authorized" => Ok(ConfirmState::Confirmed),
            //"Unconfirmed" | "Unauthorized" => Ok(ConfirmState::Unconfirmed),
            "Unconfirmed" => Ok(ConfirmState::Unconfirmed),
            "Confirmed" => Ok(ConfirmState::Confirmed),
            "Authorized" => Ok(ConfirmState::Authorized),
            "Bolcked" => Ok(ConfirmState::Blocked),
            _s => Err(E::custom(format!("Unknown string value: {}", _s))),
        }
    }
}

impl<'de> Deserialize<'de> for ConfirmState {
    fn deserialize<D>(deserializer: D) -> Result<self::Value, D::Error>
    where
        D: Deserializer<'de>,
    {
        deserializer.deserialize_any(ConfirmStateVisitor)
    }
}