use std::fmt;

use serde::{Deserialize, Deserializer, Serialize, Serializer, de::Error as _};
use time::{OffsetDateTime, format_description::well_known::Rfc3339};

pub const MAX_SAFE_INTEGER: u64 = 9_007_199_254_740_991;

#[derive(Clone, Debug, Eq, PartialEq, Serialize, Deserialize)]
#[serde(transparent)]
pub struct NullableDto<T>(pub Option<T>);

pub(crate) fn optional_nullable<'de, D, T>(
    deserializer: D,
) -> Result<Option<NullableDto<T>>, D::Error>
where
    D: Deserializer<'de>,
    T: Deserialize<'de>,
{
    NullableDto::deserialize(deserializer).map(Some)
}

#[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
pub struct SafeIntegerDto(u64);

impl SafeIntegerDto {
    pub fn new(value: u64) -> Result<Self, WireValueError> {
        if value > MAX_SAFE_INTEGER {
            return Err(WireValueError::SafeInteger);
        }
        Ok(Self(value))
    }

    #[must_use]
    pub const fn get(self) -> u64 {
        self.0
    }
}

#[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
pub struct SignedSafeIntegerDto(i64);

impl SignedSafeIntegerDto {
    pub fn new(value: i64) -> Result<Self, WireValueError> {
        if value.unsigned_abs() > MAX_SAFE_INTEGER {
            return Err(WireValueError::SafeInteger);
        }
        Ok(Self(value))
    }

    #[must_use]
    pub const fn get(self) -> i64 {
        self.0
    }
}

impl Serialize for SignedSafeIntegerDto {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: Serializer,
    {
        serializer.serialize_i64(self.0)
    }
}

impl<'de> Deserialize<'de> for SignedSafeIntegerDto {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: Deserializer<'de>,
    {
        Self::new(i64::deserialize(deserializer)?).map_err(D::Error::custom)
    }
}

impl Serialize for SafeIntegerDto {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: Serializer,
    {
        serializer.serialize_u64(self.0)
    }
}

impl<'de> Deserialize<'de> for SafeIntegerDto {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: Deserializer<'de>,
    {
        Self::new(u64::deserialize(deserializer)?).map_err(D::Error::custom)
    }
}

#[derive(Clone, Copy, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
pub struct PositiveIntegerDto(SafeIntegerDto);

impl PositiveIntegerDto {
    pub fn new(value: u64) -> Result<Self, WireValueError> {
        let value = SafeIntegerDto::new(value)?;
        if value.get() == 0 {
            return Err(WireValueError::PositiveInteger);
        }
        Ok(Self(value))
    }

    #[must_use]
    pub const fn get(self) -> u64 {
        self.0.get()
    }
}

impl Serialize for PositiveIntegerDto {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: Serializer,
    {
        serializer.serialize_u64(self.get())
    }
}

impl<'de> Deserialize<'de> for PositiveIntegerDto {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: Deserializer<'de>,
    {
        Self::new(u64::deserialize(deserializer)?).map_err(D::Error::custom)
    }
}

#[derive(Clone, Copy, Debug, Default, Eq, Hash, PartialEq)]
pub struct SchemaVersionDto;

impl Serialize for SchemaVersionDto {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: Serializer,
    {
        serializer.serialize_u8(1)
    }
}

impl<'de> Deserialize<'de> for SchemaVersionDto {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: Deserializer<'de>,
    {
        if u8::deserialize(deserializer)? != 1 {
            return Err(D::Error::custom("unsupported schema version"));
        }
        Ok(Self)
    }
}

#[derive(Clone, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
pub struct CursorDto(String);

impl CursorDto {
    pub fn parse(value: impl Into<String>) -> Result<Self, WireValueError> {
        let value = value.into();
        if !(16..=2048).contains(&value.chars().count()) {
            return Err(WireValueError::Cursor);
        }
        Ok(Self(value))
    }

    #[must_use]
    pub fn as_str(&self) -> &str {
        &self.0
    }
}

impl Serialize for CursorDto {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: Serializer,
    {
        serializer.serialize_str(&self.0)
    }
}

impl<'de> Deserialize<'de> for CursorDto {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: Deserializer<'de>,
    {
        Self::parse(String::deserialize(deserializer)?).map_err(D::Error::custom)
    }
}

#[derive(Clone, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
pub struct DateTimeDto(String);

impl DateTimeDto {
    pub fn parse(value: impl Into<String>) -> Result<Self, WireValueError> {
        let value = value.into();
        OffsetDateTime::parse(&value, &Rfc3339).map_err(|_| WireValueError::DateTime)?;
        Ok(Self(value))
    }

    #[must_use]
    pub fn as_str(&self) -> &str {
        &self.0
    }
}

impl Serialize for DateTimeDto {
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: Serializer,
    {
        serializer.serialize_str(&self.0)
    }
}

impl<'de> Deserialize<'de> for DateTimeDto {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: Deserializer<'de>,
    {
        Self::parse(String::deserialize(deserializer)?).map_err(D::Error::custom)
    }
}

#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub enum WireValueError {
    SafeInteger,
    PositiveInteger,
    Cursor,
    DateTime,
}

impl fmt::Display for WireValueError {
    fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
        let message = match self {
            Self::SafeInteger => "integer exceeds the interoperable JSON range",
            Self::PositiveInteger => "expected a positive integer",
            Self::Cursor => "invalid cursor length",
            Self::DateTime => "invalid RFC 3339 date-time",
        };
        formatter.write_str(message)
    }
}

impl std::error::Error for WireValueError {}