//! TRACES: NFR-ARCH-4
//! Typed export failures.
//!
//! Every variant is something a caller can act on or report. A batch export
//! runs unattended over hundreds of frames (FR-EXP-7), so "what went wrong
//! with which file" has to survive as data rather than as a log line.

use dr_types::{ColourSpace, ExportFormat};

#[derive(Debug, thiserror::Error)]
pub enum ExportError {
    #[error("frame buffer is {got} bytes, expected {expected}")]
    FrameSize { expected: usize, got: usize },

    #[error("frame has no pixels")]
    EmptyFrame,

    /// Asked for a format with no encoder in this build.
    ///
    /// Not a panic and not a silent substitution: the settings page offers
    /// AVIF and JPEG XL because FR-EXP-1 lists them, and a build without them
    /// should say so rather than quietly writing a JPEG under a `.avif` name.
    #[error("{} export is not supported yet", .0.label())]
    FormatUnsupported(ExportFormat),

    /// Asked for a colour space the pipeline does not render to.
    ///
    /// See the note in `export`: the shader clips to sRGB before this crate
    /// sees a pixel, so a wider space could only be a mislabelling.
    #[error("{} export needs a pipeline that renders to it", .0.label())]
    ColourSpaceUnsupported(ColourSpace),

    #[error("encoding failed: {0}")]
    Encode(String),
}