//! OCR via libtesseract (dynamic link, gated by the `ocr` cargo feature).
//!
//! `leptess` wraps `tesseract-sys` (bindgen-generated bindings to libtesseract +
//! libleptonica). At build time bindgen reads /usr/include/tesseract/*.h and emits
//! the Rust extern declarations; at runtime we dynamic-link against
//! `libtesseract.so` / `libleptonica.so` already present on the system.

use image::DynamicImage;
use leptess::LepTess;

use crate::error::{BlastError, Result};
use crate::shhh::encode_png;

/// Run OCR on `img` using the given language tag (e.g. "eng", "eng+deu").
/// Returns the recognized text with trailing whitespace trimmed.
///
/// leptess only exposes `set_image_from_mem` (decodes via leptonica), so we
/// round-trip through PNG. Re-encoding is cheap relative to OCR runtime.
pub fn recognize(img: &DynamicImage, language: &str) -> Result<String> {
    let mut lt = LepTess::new(None, language)
        .map_err(|e| BlastError::Other(format!("tesseract init: {e}")))?;

    let png = encode_png(img).map_err(|e| BlastError::Image(e.to_string()))?;
    lt.set_image_from_mem(&png)
        .map_err(|e| BlastError::Other(format!("tesseract set_image: {e}")))?;

    let text = lt
        .get_utf8_text()
        .map_err(|e| BlastError::Other(format!("tesseract recognize: {e}")))?;

    Ok(text.trim().to_string())
}