src/components/sidebar.py

import streamlit as st

def render_sidebar(reset_generation_state):
    st.sidebar.title("Navigation")
    app_page = st.sidebar.radio(
        "Go to Page:",
        [
            "🎨 Image-to-SVG Vectorizer",
            "🛠️ Tool Extract",
            "⚡ Interactive Node Simplifier"
        ]
    )
    
    # Only show controls on vectorizer page
    if app_page == "🎨 Image-to-SVG Vectorizer":
        st.sidebar.header("⚙️ Adjustment Controls")

        # ----------------------------------------------------------------
        # 1. DEFINE PRESET TEMPLATES & OPTIONS
        # ----------------------------------------------------------------
        # Add "Custom" to the options list
        quality_options = [
            "High (Detailed)",
            "Moderate (Balanced)",
            "Low (Blurry/Sketchy)",
            "Custom"
        ]

        # Preset values maps
        presets = {
            "High (Detailed)": {"scale_val": 2.5, "canny_low_val": 5, "canny_high_val": 40},
            "Moderate (Balanced)": {"scale_val": 2.0, "canny_low_val": 10, "canny_high_val": 70},
            "Low (Blurry/Sketchy)": {"scale_val": 1.2, "canny_low_val": 40, "canny_high_val": 150}
        }

        # Initialize session state variables safely on first run
        if "quality_val" not in st.session_state:
            st.session_state.quality_val = "Moderate (Balanced)"
        if "scale_val" not in st.session_state:
            st.session_state.scale_val = 2.0
        if "canny_low_val" not in st.session_state:
            st.session_state.canny_low_val = 10
        if "canny_high_val" not in st.session_state:
            st.session_state.canny_high_val = 70

        # ----------------------------------------------------------------
        # 2. CALLBAK FUNCTIONS FOR STATE MANAGEMENT
        # ----------------------------------------------------------------
        def on_preset_change():
            """Triggered when the user changes the dropdown explicitly."""
            reset_generation_state()
            selected = st.session_state.quality_val
            # If they chose a real template, force-apply those values
            if selected in presets:
                st.session_state.scale_val = presets[selected]["scale_val"]
                st.session_state.canny_low_val = presets[selected]["canny_low_val"]
                st.session_state.canny_high_val = presets[selected]["canny_high_val"]

        def on_slider_change():
            """Triggered when user tweaks any preset-controlled slider."""
            reset_generation_state()
            # If they move a slider, flip the dropdown automatically to 'Custom'
            st.session_state.quality_val = "Custom"

        # ----------------------------------------------------------------
        # 3. QUALITY PRESET DROPDOWN
        # ----------------------------------------------------------------
        current_quality = st.session_state.quality_val
        idx = quality_options.index(current_quality) if current_quality in quality_options else 1

        st.sidebar.selectbox(
            "Extraction Quality Preset",
            quality_options,
            index=idx,
            key="quality_val",  
            on_change=on_preset_change
        )

        # ----------------------------------------------------------------
        # 4. IMAGE CLEAN-UP
        # ----------------------------------------------------------------
        st.sidebar.subheader("Image Clean-up")
        
        st.sidebar.slider(
            "De-blur (Sharpening)",
            0.0, 3.0,
            key="sharpen_val",
            step=0.1,
            on_change=reset_generation_state # Independent slider
        )

        st.sidebar.slider(
            "Resize Scale",
            1.0, 3.0,
            key="scale_val",
            step=0.1,
            on_change=on_slider_change # Auto-switches preset to Custom
        )

        # ----------------------------------------------------------------
        # 5. BACKGROUND REMOVAL (GRABCUT)
        # ----------------------------------------------------------------
        st.sidebar.subheader("✂️ Background Removal")
        
        enable_grabcut = st.sidebar.checkbox(
            "Isolate Foreground Object", 
            key="enable_grabcut",
            help="Uses the GrabCut algorithm to eliminate background noise before vectorization.",
            on_change=reset_generation_state
        )
        
        if enable_grabcut:
            st.sidebar.slider(
                "Background Crop Margin", 
                1, 50, 
                key="bbox_padding", 
                step=1,
                help="Tells the algorithm how close the object is to the image edges (in pixels).",
                on_change=reset_generation_state
            )
        else:
            st.session_state.bbox_padding = 10

        # ----------------------------------------------------------------
        # 6. EDGE SETTINGS (CONTAINS PRESET TARGET SLIDERS)
        # ----------------------------------------------------------------
        st.sidebar.subheader("📐 Thresholding & Outlines")

        st.sidebar.slider(
            "Canny Low Threshold",
            5, 100,
            key="canny_low_val",
            on_change=on_slider_change # Auto-switches preset to Custom
        )

        st.sidebar.slider(
            "Canny High Threshold",
            30, 250,
            key="canny_high_val",
            on_change=on_slider_change # Auto-switches preset to Custom
        )

        # ----------------------------------------------------------------
        # 7. LINE STYLE
        # ----------------------------------------------------------------
        st.sidebar.subheader("🖋️ Line Styling")

        skeletonize = st.sidebar.checkbox(
            "Skeletonize (Single-Pixel Path)",
            key="skeletonize_val",
            on_change=reset_generation_state
        )

        if not skeletonize:
            st.sidebar.slider(
                "Contour Thickness",
                1, 5,
                key="contour_thickness_val",
                on_change=reset_generation_state
            )

            st.sidebar.slider(
                "Line Thicken (Dilate)",
                0, 3,
                key="dilate_iter_val",
                on_change=reset_generation_state
            )
        else:
            st.session_state.contour_thickness_val = 1
            st.session_state.dilate_iter_val = 0

    return app_page