import streamlit as st
import pydicom
import matplotlib.pyplot as plt
import os

# Set up the Streamlit app title
st.title("DICOM Viewer for CBCT Scans")

# Directory where DICOM files are stored in the repository
dicom_directory = "./dicom_files/"

# Function to get the slice location or image position for sorting
def get_slice_location(dicom_file):
    ds = pydicom.dcmread(dicom_file)
    # Try to get the 'Slice Location'; if not available, use 'Image Position Patient'
    if 'SliceLocation' in ds:
        return float(ds.SliceLocation)
    elif 'ImagePositionPatient' in ds:
        # 'ImagePositionPatient' is a list; use the first element (z-coordinate)
        return float(ds.ImagePositionPatient[2])
    else:
        return 0  # Default to 0 if neither tag is available

# Read all DICOM files from the directory
dicom_files = [os.path.join(dicom_directory, f) for f in os.listdir(dicom_directory) if f.endswith('.dcm')]

if dicom_files:
    # Sort DICOM files by slice location or image position
    dicom_files.sort(key=lambda x: get_slice_location(x))
    
    # Read all DICOM images (sorted)
    dicom_images = [pydicom.dcmread(file).pixel_array for file in dicom_files]

    # Interactive slider to select image index
    st.sidebar.header("Image Slider")
    image_index = st.sidebar.slider("Select Image Index", 0, len(dicom_images) - 1, 0)

    # Display the selected DICOM image
    st.header(f"Displaying Image {image_index + 1} of {len(dicom_images)}")
    fig, ax = plt.subplots()
    ax.imshow(dicom_images[image_index], cmap='gray')
    ax.axis('off')
    st.pyplot(fig)
else:
    st.write("No DICOM files found in the directory. Please check the folder and try again.")