use crate::errors::*;
use crate::facedet::postprocess::*;
use error_stack::ResultExt;
use ndarray_resize::NdFir;
use ort::{
    execution_providers::{
        CPUExecutionProvider, CoreMLExecutionProvider, ExecutionProviderDispatch,
    },
    session::{Session, builder::GraphOptimizationLevel},
    value::Tensor,
};
use std::path::Path;

#[derive(Debug)]
pub struct FaceDetection {
    session: Session,
}

pub struct FaceDetectionBuilder {
    model_data: Vec<u8>,
    execution_providers: Option<Vec<ExecutionProviderDispatch>>,
    intra_threads: Option<usize>,
    inter_threads: Option<usize>,
}

impl FaceDetectionBuilder {
    pub fn new(model: impl AsRef<[u8]>) -> crate::errors::Result<Self> {
        Ok(Self {
            model_data: model.as_ref().to_vec(),
            execution_providers: None,
            intra_threads: None,
            inter_threads: None,
        })
    }

    pub fn with_execution_providers(mut self, providers: Vec<String>) -> Self {
        let execution_providers: Vec<ExecutionProviderDispatch> = providers
            .into_iter()
            .filter_map(|provider| match provider.as_str() {
                "cpu" | "CPU" => Some(CPUExecutionProvider::default().build()),
                #[cfg(target_os = "macos")]
                "coreml" | "CoreML" => Some(CoreMLExecutionProvider::default().build()),
                _ => {
                    tracing::warn!("Unknown execution provider: {}", provider);
                    None
                }
            })
            .collect();

        if !execution_providers.is_empty() {
            self.execution_providers = Some(execution_providers);
        } else {
            tracing::warn!("No valid execution providers found, falling back to CPU");
            self.execution_providers = Some(vec![CPUExecutionProvider::default().build()]);
        }
        self
    }

    pub fn with_intra_threads(mut self, threads: usize) -> Self {
        self.intra_threads = Some(threads);
        self
    }

    pub fn with_inter_threads(mut self, threads: usize) -> Self {
        self.inter_threads = Some(threads);
        self
    }

    pub fn build(self) -> crate::errors::Result<FaceDetection> {
        let mut session_builder = Session::builder()
            .change_context(Error)
            .attach_printable("Failed to create session builder")?;

        // Set execution providers
        if let Some(providers) = self.execution_providers {
            session_builder = session_builder
                .with_execution_providers(providers)
                .change_context(Error)
                .attach_printable("Failed to set execution providers")?;
        } else {
            // Default to CPU
            session_builder = session_builder
                .with_execution_providers([CPUExecutionProvider::default().build()])
                .change_context(Error)
                .attach_printable("Failed to set default CPU execution provider")?;
        }

        // Set threading options
        if let Some(threads) = self.intra_threads {
            session_builder = session_builder
                .with_intra_threads(threads)
                .change_context(Error)
                .attach_printable("Failed to set intra threads")?;
        }

        if let Some(threads) = self.inter_threads {
            session_builder = session_builder
                .with_inter_threads(threads)
                .change_context(Error)
                .attach_printable("Failed to set inter threads")?;
        }

        // Set optimization level
        session_builder = session_builder
            .with_optimization_level(GraphOptimizationLevel::Level3)
            .change_context(Error)
            .attach_printable("Failed to set optimization level")?;

        // Create session from model bytes
        let session = session_builder
            .commit_from_memory(&self.model_data)
            .change_context(Error)
            .attach_printable("Failed to create ORT session from model bytes")?;

        tracing::info!("Successfully created ORT RetinaFace session");

        Ok(FaceDetection { session })
    }
}

impl FaceDetection {
    pub fn builder<T: AsRef<[u8]>>()
    -> fn(T) -> std::result::Result<FaceDetectionBuilder, error_stack::Report<crate::errors::Error>>
    {
        FaceDetectionBuilder::new
    }

    pub fn new(path: impl AsRef<Path>) -> crate::errors::Result<Self> {
        let model = std::fs::read(path)
            .change_context(Error)
            .attach_printable("Failed to read model file")?;
        Self::new_from_bytes(&model)
    }

    pub fn new_from_bytes(model: &[u8]) -> crate::errors::Result<Self> {
        tracing::info!("Loading ORT RetinaFace model from bytes");
        Self::builder()(model)?.build()
    }
}

impl FaceDetector for FaceDetection {
    fn run_model(
        &mut self,
        image: ndarray::ArrayView3<u8>,
    ) -> crate::errors::Result<FaceDetectionModelOutput> {
        // Resize image to 1024x1024
        let mut resized = image
            .fast_resize(1024, 1024, None)
            .change_context(Error)
            .attach_printable("Failed to resize image")?
            .mapv(|f| f as f32);

        // Apply mean subtraction: [104, 117, 123] for BGR format
        resized
            .axis_iter_mut(ndarray::Axis(2))
            .zip([104.0, 117.0, 123.0])
            .for_each(|(mut array, mean)| {
                array.map_inplace(|v| *v -= mean);
            });

        // Convert from HWC to NCHW format (add batch dimension and transpose)
        let input_tensor = resized
            .permuted_axes((2, 0, 1))
            .insert_axis(ndarray::Axis(0))
            .as_standard_layout()
            .into_owned();

        tracing::trace!("Input tensor shape: {:?}", input_tensor.shape());

        // Create ORT input tensor
        let input_value = Tensor::from_array(input_tensor)
            .change_context(Error)
            .attach_printable("Failed to create input tensor")?;

        // Run inference
        tracing::debug!("Running ORT RetinaFace inference");
        let outputs = self
            .session
            .run(ort::inputs!["input" => input_value])
            .change_context(Error)
            .attach_printable("Failed to run inference")?;

        // Extract outputs by name
        let bbox_output = outputs
            .get("bbox")
            .ok_or(Error)
            .attach_printable("Missing bbox output from model")?
            .try_extract_tensor::<f32>()
            .change_context(Error)
            .attach_printable("Failed to extract bbox tensor")?;

        let confidence_output = outputs
            .get("confidence")
            .ok_or(Error)
            .attach_printable("Missing confidence output from model")?
            .try_extract_tensor::<f32>()
            .change_context(Error)
            .attach_printable("Failed to extract confidence tensor")?;

        let landmark_output = outputs
            .get("landmark")
            .ok_or(Error)
            .attach_printable("Missing landmark output from model")?
            .try_extract_tensor::<f32>()
            .change_context(Error)
            .attach_printable("Failed to extract landmark tensor")?;

        // Get tensor shapes and data
        let (bbox_shape, bbox_data) = bbox_output;
        let (confidence_shape, confidence_data) = confidence_output;
        let (landmark_shape, landmark_data) = landmark_output;

        tracing::trace!(
            "Output shapes - bbox: {:?}, confidence: {:?}, landmark: {:?}",
            bbox_shape,
            confidence_shape,
            landmark_shape
        );

        // Convert to ndarray format
        let bbox_dims = bbox_shape.as_ref();
        let confidence_dims = confidence_shape.as_ref();
        let landmark_dims = landmark_shape.as_ref();

        let bbox_array = ndarray::Array3::from_shape_vec(
            (
                bbox_dims[0] as usize,
                bbox_dims[1] as usize,
                bbox_dims[2] as usize,
            ),
            bbox_data.to_vec(),
        )
        .change_context(Error)
        .attach_printable("Failed to create bbox ndarray")?;

        let confidence_array = ndarray::Array3::from_shape_vec(
            (
                confidence_dims[0] as usize,
                confidence_dims[1] as usize,
                confidence_dims[2] as usize,
            ),
            confidence_data.to_vec(),
        )
        .change_context(Error)
        .attach_printable("Failed to create confidence ndarray")?;

        let landmark_array = ndarray::Array3::from_shape_vec(
            (
                landmark_dims[0] as usize,
                landmark_dims[1] as usize,
                landmark_dims[2] as usize,
            ),
            landmark_data.to_vec(),
        )
        .change_context(Error)
        .attach_printable("Failed to create landmark ndarray")?;

        Ok(FaceDetectionModelOutput {
            bbox: bbox_array,
            confidence: confidence_array,
            landmark: landmark_array,
        })
    }
}