//! QR Code generation for WireGuard mobile enrollment.

use crate::error::{Result, WireGuardError};
use base64::Engine;
use image::Luma;
use qrcode::QrCode;
use qrcode::render::svg;

/// Generate SVG string for a WireGuard configuration.
pub fn generate_qr_svg(content: &str) -> Result<String> {
    let code = QrCode::new(content.as_bytes())
        .map_err(|e| WireGuardError::Qr(format!("Failed to generate QR code: {e}")))?;

    let image = code
        .render::<svg::Color>()
        .min_dimensions(256, 256)
        .dark_color(svg::Color("#000000"))
        .light_color(svg::Color("#ffffff"))
        .build();

    Ok(image)
}

/// Generate PNG bytes for a WireGuard configuration.
pub fn generate_qr_png_bytes(content: &str) -> Result<Vec<u8>> {
    let code = QrCode::new(content.as_bytes())
        .map_err(|e| WireGuardError::Qr(format!("Failed to generate QR code: {e}")))?;

    let image = code.render::<Luma<u8>>().min_dimensions(300, 300).build();

    let mut buffer = std::io::Cursor::new(Vec::new());
    image
        .write_to(&mut buffer, image::ImageFormat::Png)
        .map_err(|e| WireGuardError::Qr(format!("Failed to encode QR PNG: {e}")))?;

    Ok(buffer.into_inner())
}

/// Generate base64-encoded PNG string for a WireGuard configuration.
pub fn generate_qr_base64(content: &str) -> Result<String> {
    let png_bytes = generate_qr_png_bytes(content)?;
    Ok(base64::engine::general_purpose::STANDARD.encode(png_bytes))
}

/// Generate base64 Data URL (data:image/png;base64,...) for embedding in HTML / UI.
pub fn generate_qr_data_url(content: &str) -> Result<String> {
    let b64 = generate_qr_base64(content)?;
    Ok(format!("data:image/png;base64,{b64}"))
}

/// Generate ASCII QR code for direct CLI rendering.
pub fn generate_qr_ascii(content: &str) -> Result<String> {
    let code = QrCode::new(content.as_bytes())
        .map_err(|e| WireGuardError::Qr(format!("Failed to generate QR code: {e}")))?;

    let string = code
        .render::<qrcode::render::unicode::Dense1x2>()
        .dark_color(qrcode::render::unicode::Dense1x2::Dark)
        .light_color(qrcode::render::unicode::Dense1x2::Light)
        .build();

    Ok(string)
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_qr_generation_svg_png_ascii() {
        let text = "[Interface]\nPrivateKey = aaaa\n";
        let svg = generate_qr_svg(text).expect("svg");
        assert!(svg.contains("<svg"));

        let png = generate_qr_png_bytes(text).expect("png");
        assert!(!png.is_empty());
        assert_eq!(&png[1..4], b"PNG");

        let data_url = generate_qr_data_url(text).expect("data url");
        assert!(data_url.starts_with("data:image/png;base64,"));

        let ascii = generate_qr_ascii(text).expect("ascii");
        assert!(!ascii.is_empty());
    }
}