qubit-value 0.13.1

// =============================================================================
//    Copyright (c) 2025 - 2026 Haixing Hu.
//
//    SPDX-License-Identifier: Apache-2.0
//
//    Licensed under the Apache License, Version 2.0.
// =============================================================================

//! Unversioned V1 payload for use inside an already-versioned protocol.

#[cfg(feature = "json")]
use std::io::Write;

#[cfg(feature = "json")]
use qubit_budget::json::JsonDecodeLimits;
#[cfg(feature = "json")]
use qubit_budget::json::JsonDecodeSession;
#[cfg(feature = "json")]
use qubit_budget::json::JsonEncodeLimits;
#[cfg(feature = "json")]
use qubit_budget::json::JsonEncodeSession;
#[cfg(feature = "json")]
use qubit_json::decode::JsonDecoder;
#[cfg(feature = "json")]
use qubit_json::encode::JsonEncoder;
use serde::Serialize;
use serde::Serializer;

use super::ValueWireEncodeError;
#[cfg(feature = "json")]
use super::ValueWireEncodePreflight;
use super::WireShapeRef;
use super::value_wire_payload_ref_v1::validate_value;
use super::value_wire_payload_ref_v1::validate_values;
#[cfg(feature = "json")]
use super::value_wire_payload_v1_seed::ValueWirePayloadV1Seed;
use crate::MultiValues;
use crate::Value;
use crate::ValueContainer;
#[cfg(feature = "json")]
use crate::ValueWireDecodeError;

/// Typed V1 scalar-or-collection payload without an enclosing version field.
///
/// Runtime JSON numbers must round trip to the same `serde_json::Number` under
/// the strict `qubit-json` number model. A number that would change identity
/// returns the JSON-gated `JsonNumberNotRoundTrippable` error; the error does
/// not expose the number text.
///
/// Deserialization is intentionally available through
/// [`crate::ValueWirePayloadV1Seed`], which lets a bounded decoder control the
/// complete input and structure.
///
/// # Examples
///
/// ```
/// use qubit_value::{Value, ValueWirePayloadV1};
///
/// let payload = ValueWirePayloadV1::try_from(Value::from(42_i32)).unwrap();
/// let encoded = serde_json::to_string(&payload).unwrap();
/// assert_eq!(encoded, r#"{"scalar":{"int32":42}}"#);
/// assert_eq!(payload.into_container().get_first::<i32>().unwrap(), 42);
/// ```
#[must_use]
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub struct ValueWirePayloadV1 {
    /// Preserved runtime shape and payload.
    value: ValueContainer,
}

impl ValueWirePayloadV1 {
    /// Returns the default JSON resource profile for complete V1 payloads.
    ///
    /// # Returns
    ///
    /// Decode limits suitable for one standalone unversioned V1 payload.
    #[cfg(feature = "json")]
    #[must_use = "the V1 JSON profile should be applied to a budget"]
    #[inline(always)]
    #[cfg_attr(docsrs, doc(cfg(feature = "json")))]
    pub fn default_json_decode_limits() -> JsonDecodeLimits {
        super::default_json_decode_limits()
    }

    /// Returns the default JSON resource profile for complete V1 payloads.
    ///
    /// # Returns
    ///
    /// Encode limits suitable for one standalone unversioned V1 payload.
    #[cfg(feature = "json")]
    #[must_use = "the V1 JSON profile should be applied to an encode session"]
    #[inline]
    #[cfg_attr(docsrs, doc(cfg(feature = "json")))]
    pub fn default_json_encode_limits() -> JsonEncodeLimits {
        super::default_json_encode_limits()
    }

    /// Decodes a complete V1 JSON payload using default resource limits.
    ///
    /// Prefer this entry point when the payload itself is the complete
    /// untrusted document. Embedded protocols should share one budget across
    /// all payloads in their complete document.
    ///
    /// # Parameters
    ///
    /// * `input` - Complete UTF-8 JSON payload to decode.
    ///
    /// # Returns
    ///
    /// The decoded unversioned V1 payload.
    ///
    /// # Errors
    ///
    /// Returns a resource error when the input or decoded structure exceeds the
    /// default limits, [`ValueWireDecodeError::Syntax`] for JSON syntax
    /// failures, or [`ValueWireDecodeError::InvalidJson`] for invalid UTF-8
    /// or a payload that does not satisfy the V1 shape, type, or value
    /// constraints.
    #[cfg(feature = "json")]
    #[inline]
    #[cfg_attr(docsrs, doc(cfg(feature = "json")))]
    pub fn decode_json_slice(input: &[u8]) -> Result<Self, ValueWireDecodeError> {
        Self::decode_json_slice_with_limits(input, Self::default_json_decode_limits())
    }

    /// Decodes a complete V1 JSON payload using explicit resource limits.
    ///
    /// # Parameters
    ///
    /// * `input` - Complete UTF-8 JSON payload to decode.
    /// * `limits` - Resource limits enforced during decoding.
    ///
    /// # Returns
    ///
    /// The decoded unversioned V1 payload.
    ///
    /// # Errors
    ///
    /// Returns a resource error when `input` or its decoded structure exceeds
    /// `limits`, [`ValueWireDecodeError::Syntax`] for JSON syntax failures, or
    /// [`ValueWireDecodeError::InvalidJson`] for invalid UTF-8 or a payload
    /// that does not satisfy the V1 shape, type, or value constraints.
    #[cfg(feature = "json")]
    #[inline]
    #[cfg_attr(docsrs, doc(cfg(feature = "json")))]
    pub fn decode_json_slice_with_limits(
        input: &[u8],
        limits: JsonDecodeLimits,
    ) -> Result<Self, ValueWireDecodeError> {
        let session = JsonDecodeSession::from_limits(limits);
        JsonDecoder::new(session)
            .decode_unique_seed_utf8(ValueWirePayloadV1Seed::new(), input)
            .map_err(ValueWireDecodeError::from)
    }

    /// Wraps a payload decoded through V1's finite-number Serde adapters.
    ///
    /// # Parameters
    ///
    /// * `value` - Already validated decoded runtime container.
    ///
    /// # Returns
    ///
    /// An owned unversioned V1 payload.
    #[inline]
    pub(in crate::value_wire) const fn from_decoded(value: ValueContainer) -> Self {
        Self { value }
    }

    /// Builds a payload after enforcing V1's representational constraints.
    ///
    /// # Parameters
    ///
    /// * `value` - Runtime container to validate and own.
    ///
    /// # Returns
    ///
    /// A validated owned V1 payload.
    ///
    /// # Errors
    ///
    /// Returns [`ValueWireEncodeError`] when any contained payload is not
    /// representable by V1, including an instant outside the supported UTC
    /// year range.
    fn try_new(value: ValueContainer) -> Result<Self, ValueWireEncodeError> {
        match &value {
            ValueContainer::Scalar(value) => validate_value(value)?,
            ValueContainer::Collection(values) => validate_values(values)?,
        }
        Ok(Self { value })
    }

    /// Borrows the preserved runtime value.
    ///
    /// # Returns
    ///
    /// A shared reference to the preserved scalar-or-collection container.
    #[must_use = "the borrowed value container should be used"]
    #[inline(always)]
    pub const fn container(&self) -> &ValueContainer {
        &self.value
    }

    /// Encodes this V1 payload into a compact JSON vector with default limits.
    ///
    /// # Returns
    ///
    /// Compact UTF-8 JSON bytes for this unversioned payload.
    ///
    /// # Errors
    ///
    /// Returns [`ValueWireEncodeError::Budget`] when the payload exceeds the
    /// default JSON resource profile.
    #[cfg(feature = "json")]
    #[inline(always)]
    #[cfg_attr(docsrs, doc(cfg(feature = "json")))]
    pub fn to_json_vec(&self) -> Result<Vec<u8>, ValueWireEncodeError> {
        self.to_json_vec_with_limits(Self::default_json_encode_limits())
    }

    /// Encodes this V1 payload into a bounded compact JSON vector.
    ///
    /// # Parameters
    ///
    /// * `limits` - Resource limits enforced during encoding.
    ///
    /// # Returns
    ///
    /// Compact UTF-8 JSON bytes for this unversioned payload.
    ///
    /// Runs a conservative payload preflight before encoding, then enforces
    /// `limits` authoritatively while encoding. The preflight may report a
    /// lower-bound budget error and does not bound every preparation
    /// allocation.
    ///
    /// # Errors
    ///
    /// Returns [`ValueWireEncodeError`] when preflight or final encoding
    /// exceeds `limits`, or the payload cannot be serialized.
    #[cfg(feature = "json")]
    #[cfg_attr(docsrs, doc(cfg(feature = "json")))]
    pub fn to_json_vec_with_limits(
        &self,
        limits: JsonEncodeLimits,
    ) -> Result<Vec<u8>, ValueWireEncodeError> {
        ValueWireEncodePreflight::new(limits)
            .check_container(self.container())
            .map_err(ValueWireEncodeError::from)?;
        let session = JsonEncodeSession::from_limits(limits);
        JsonEncoder::new(session)
            .to_vec(self)
            .map_err(ValueWireEncodeError::from)
    }

    /// Encodes this V1 payload to a writer with default limits.
    ///
    /// # Type Parameters
    ///
    /// * `W` - Destination writer type.
    ///
    /// # Parameters
    ///
    /// * `writer` - Destination receiving the complete JSON payload.
    ///
    /// # Returns
    ///
    /// `Ok(())` after the complete payload is written.
    ///
    /// The complete payload is buffered and admitted before this method writes
    /// its bytes to the destination. Preflight, serialization, or budget
    /// rejection does not write this payload. An I/O error may leave an
    /// accepted prefix in the writer; do not blindly retry a complete
    /// payload on the same destination.
    ///
    /// This method does not explicitly flush the writer. Success means the
    /// writer accepted all payload bytes, not that they were flushed,
    /// persisted, or received by a remote peer. Pass `&mut writer` to
    /// retain ownership of a buffered writer, then call `flush()` and
    /// handle its error separately. Passing an owned writer may invoke that
    /// writer's drop behavior; errors from an implicit drop-time flush are
    /// not returned by this method.
    ///
    /// # Errors
    ///
    /// Returns [`ValueWireEncodeError::Budget`] for resource-limit failures or
    /// [`ValueWireEncodeError::Io`] when `writer` rejects output.
    #[cfg(feature = "json")]
    #[inline(always)]
    #[cfg_attr(docsrs, doc(cfg(feature = "json")))]
    pub fn to_json_writer<W>(&self, writer: W) -> Result<(), ValueWireEncodeError>
    where
        W: Write,
    {
        self.to_json_writer_with_limits(writer, Self::default_json_encode_limits())
    }

    /// Encodes this V1 payload to a writer after enforcing JSON budgets.
    ///
    /// # Type Parameters
    ///
    /// * `W` - Destination writer type.
    ///
    /// # Parameters
    ///
    /// * `writer` - Destination receiving the complete JSON payload.
    /// * `limits` - Resource limits enforced during encoding.
    ///
    /// # Returns
    ///
    /// `Ok(())` after the complete payload is written.
    ///
    /// Runs a conservative payload preflight before encoding, then enforces
    /// `limits` authoritatively while encoding. The preflight may report a
    /// lower-bound budget error and does not bound every preparation
    /// allocation.
    ///
    /// The complete payload is buffered and admitted before this method writes
    /// its bytes to the destination. Preflight, serialization, or budget
    /// rejection does not write this payload. An I/O error may leave an
    /// accepted prefix in the writer; do not blindly retry a complete
    /// payload on the same destination.
    ///
    /// This method does not explicitly flush the writer. Success means the
    /// writer accepted all payload bytes, not that they were flushed,
    /// persisted, or received by a remote peer. Pass `&mut writer` to
    /// retain ownership of a buffered writer, then call `flush()` and
    /// handle its error separately. Passing an owned writer may invoke that
    /// writer's drop behavior; errors from an implicit drop-time flush are
    /// not returned by this method.
    ///
    /// # Errors
    ///
    /// Returns [`ValueWireEncodeError`] when preflight or final encoding
    /// exceeds `limits`, the payload cannot be serialized, or `writer` rejects
    /// output.
    #[cfg(feature = "json")]
    #[cfg_attr(docsrs, doc(cfg(feature = "json")))]
    pub fn to_json_writer_with_limits<W>(
        &self,
        mut writer: W,
        limits: JsonEncodeLimits,
    ) -> Result<(), ValueWireEncodeError>
    where
        W: Write,
    {
        ValueWireEncodePreflight::new(limits)
            .check_container(self.container())
            .map_err(ValueWireEncodeError::from)?;
        let session = JsonEncodeSession::from_limits(limits);
        JsonEncoder::new(session)
            .write_buffered(&mut writer, self)
            .map_err(ValueWireEncodeError::from)
    }

    /// Consumes this payload and returns its runtime value.
    ///
    /// # Returns
    ///
    /// The preserved scalar-or-collection container.
    #[inline(always)]
    pub fn into_container(self) -> ValueContainer {
        self.value
    }
}

impl TryFrom<Value> for ValueWirePayloadV1 {
    /// Validation failure when the runtime value cannot satisfy the V1 wire
    /// contract.
    type Error = ValueWireEncodeError;

    /// Validates a scalar for use in a V1 payload.
    ///
    /// # Parameters
    ///
    /// * `value` - Scalar to validate and take ownership of.
    ///
    /// # Returns
    ///
    /// A validated owned unversioned V1 payload.
    ///
    /// # Errors
    ///
    /// Returns [`ValueWireEncodeError::NonFiniteFloat`] for a non-finite
    /// float, [`ValueWireEncodeError::BigDecimalScaleTooLarge`] for a decimal
    /// whose exponent is outside V1's supported range, or
    /// [`ValueWireEncodeError::InstantYearOutOfRange`] for an instant outside
    /// the supported UTC year range.
    /// With the `json` feature, returns `JsonNumberNotRoundTrippable` if a
    /// runtime JSON number, including a nested number, cannot preserve its
    /// `serde_json::Number` identity under the V1 number model.
    #[inline]
    fn try_from(value: Value) -> Result<Self, Self::Error> {
        Self::try_new(value.into())
    }
}

impl TryFrom<MultiValues> for ValueWirePayloadV1 {
    /// Validation failure when the runtime value cannot satisfy the V1 wire
    /// contract.
    type Error = ValueWireEncodeError;

    /// Validates a collection for use in a V1 payload.
    ///
    /// # Parameters
    ///
    /// * `value` - Homogeneous collection to validate and take ownership of.
    ///
    /// # Returns
    ///
    /// A validated owned unversioned V1 payload.
    ///
    /// # Errors
    ///
    /// Returns [`ValueWireEncodeError::NonFiniteFloat`] for a non-finite
    /// float element, [`ValueWireEncodeError::BigDecimalScaleTooLarge`] for
    /// an element whose decimal exponent is outside V1's supported range, or
    /// [`ValueWireEncodeError::InstantYearOutOfRange`] for an instant outside
    /// the supported UTC year range.
    /// With the `json` feature, returns `JsonNumberNotRoundTrippable` if any
    /// runtime JSON number in the collection, including a nested number,
    /// cannot preserve its `serde_json::Number` identity under the V1 number
    /// model.
    #[inline(always)]
    fn try_from(value: MultiValues) -> Result<Self, Self::Error> {
        Self::try_new(value.into())
    }
}

impl TryFrom<ValueContainer> for ValueWirePayloadV1 {
    /// Validation failure when the runtime value cannot satisfy the V1 wire
    /// contract.
    type Error = ValueWireEncodeError;

    /// Validates an explicitly shaped value for use in a V1 payload.
    ///
    /// # Parameters
    ///
    /// * `value` - Scalar-or-collection container whose shape and ownership are
    ///   preserved.
    ///
    /// # Returns
    ///
    /// A validated owned unversioned V1 payload.
    ///
    /// # Errors
    ///
    /// Returns [`ValueWireEncodeError::NonFiniteFloat`] for a non-finite
    /// float, [`ValueWireEncodeError::BigDecimalScaleTooLarge`] for a decimal
    /// whose exponent is outside V1's supported range, or
    /// [`ValueWireEncodeError::InstantYearOutOfRange`] for an instant outside
    /// the supported UTC year range.
    /// With the `json` feature, returns `JsonNumberNotRoundTrippable` if a
    /// runtime JSON number in either the scalar or collection shape, including
    /// a nested number, cannot preserve its `serde_json::Number` identity
    /// under the V1 number model.
    #[inline]
    fn try_from(value: ValueContainer) -> Result<Self, Self::Error> {
        Self::try_new(value)
    }
}

impl From<ValueWirePayloadV1> for ValueContainer {
    /// Extracts the shaped runtime value from a V1 payload without cloning.
    ///
    /// # Parameters
    ///
    /// * `value` - Owned payload to consume.
    ///
    /// # Returns
    ///
    /// The preserved runtime container with its original scalar-or-collection
    /// shape.
    #[inline]
    fn from(value: ValueWirePayloadV1) -> Self {
        value.into_container()
    }
}

impl Serialize for ValueWirePayloadV1 {
    /// Serializes the unversioned V1 shape through borrowed runtime values.
    ///
    /// # Type Parameters
    ///
    /// * `S` - Serde serializer selecting the output format and error type.
    ///
    /// # Parameters
    ///
    /// * `serializer` - Destination serializer receiving the
    ///   scalar-or-collection shape.
    ///
    /// # Returns
    ///
    /// The serializer's success value after emitting the complete payload.
    ///
    /// # Errors
    ///
    /// Returns the serializer's error if the destination rejects the shape or
    /// values.
    #[inline(always)]
    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
    where
        S: Serializer,
    {
        WireShapeRef::from(&self.value).serialize(serializer)
    }
}