// SPDX-FileCopyrightText: Copyright (c) 2025-2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
// SPDX-License-Identifier: Apache-2.0

use derive_builder::Builder;
use serde::{Deserialize, Serialize};
use utoipa::ToSchema;
use validator::{Validate, ValidationError};

pub trait NvExtProvider {
    fn nvext(&self) -> Option<&NvExt>;
}

/// NVIDIA extensions to the OpenAI Images API
#[derive(ToSchema, Serialize, Deserialize, Builder, Validate, Debug, Clone)]
#[validate(schema(function = "validate_nv_ext"))]
pub struct NvExt {
    /// Annotations
    /// User requests triggers which result in the request issue back out-of-band information in the SSE
    /// stream using the `event:` field.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    #[builder(default, setter(strip_option))]
    pub annotations: Option<Vec<String>>,

    /// A text description of the undesired image(s).
    #[serde(skip_serializing_if = "Option::is_none")]
    #[builder(default, setter(strip_option))]
    pub negative_prompt: Option<String>,

    /// The number of denoising steps. More denoising steps usually lead to a higher quality image at the expense of slower inference.
    #[serde(skip_serializing_if = "Option::is_none")]
    #[builder(default, setter(strip_option))]
    pub num_inference_steps: Option<u8>,

    /// The CFG scale. Higher values usually lead to more coherent images.
    #[serde(skip_serializing_if = "Option::is_none")]
    #[builder(default, setter(strip_option))]
    pub guidance_scale: Option<f32>,

    /// The seed for the random number generator.
    /// i64 to match PyTorch's torch.manual_seed() accepted range.
    #[serde(skip_serializing_if = "Option::is_none")]
    #[builder(default, setter(strip_option))]
    pub seed: Option<i64>,
}

impl Default for NvExt {
    fn default() -> Self {
        NvExt::builder().build().unwrap()
    }
}

impl NvExt {
    pub fn builder() -> NvExtBuilder {
        NvExtBuilder::default()
    }
}

fn validate_nv_ext(_nv_ext: &NvExt) -> Result<(), ValidationError> {
    Ok(())
}

impl NvExtBuilder {
    pub fn add_annotation(&mut self, annotation: impl Into<String>) -> &mut Self {
        self.annotations
            .get_or_insert_with(|| Some(vec![]))
            .as_mut()
            .expect("annotations should always be Some(Vec)")
            .push(annotation.into());
        self
    }
}
