use crate::error::DichroismError;
use crate::result::Result;
use base64::decode;
use image::imageops::FilterType;
use image::DynamicImage;
use image::GenericImageView;
use regex::Regex;
use std::path::PathBuf;
use uuid::Uuid;

use once_cell::sync::Lazy;

static DATA_URI_RE: Lazy<Regex> = Lazy::new(|| {
    Regex::new("^data:image/(png|jpeg);base64,(?P<data>.+)")
        .expect("Couldn't parse data URI Regex.")
});

pub struct NewProductImageData {
    original: DynamicImage,  // original, just for safe-keeping
    fullsize: DynamicImage,  // full-size, "zoomed" view
    base: DynamicImage,      // basic viewing
    thumbnail: DynamicImage, // tiny, square thumbnail
}

impl NewProductImageData {
    pub fn from_data_uri(uri: &str) -> Result<Self> {
        let data = DATA_URI_RE
            .captures(uri)
            .ok_or(DichroismError::UriDataExtract)?
            .name("data")
            .ok_or(DichroismError::UriDataExtract)?
            .as_str();
        let original = image::load_from_memory(&decode(data)?)?;
        let fullsize = original.resize(1000, 1000, FilterType::Lanczos3);
        let base = original.resize(640, 640, FilterType::Lanczos3);

        let (width, height) = original.dimensions();
        let thumbnail = if width > height {
            let offset = (width - height) / 2;
            original.crop_imm(offset, 0, width - offset * 2, height)
        } else {
            let offset = (height - width) / 2;
            original.crop_imm(0, offset, width, height - offset * 2)
        }
        .resize(300, 300, FilterType::Lanczos3);

        Ok(NewProductImageData {
            original,
            fullsize,
            base,
            thumbnail,
        })
    }

    pub fn commit(self, prefix: &str) -> Result<NewProductImages> {
        Ok(NewProductImages {
            original: self.commit_single(prefix, &self.original)?,
            fullsize: self.commit_single(prefix, &self.fullsize)?,
            base: self.commit_single(prefix, &self.base)?,
            thumbnail: self.commit_single(prefix, &self.thumbnail)?,
        })
    }

    fn commit_single(&self, prefix: &str, image: &DynamicImage) -> Result<String> {
        let base_name = Uuid::new_v3(&Uuid::NAMESPACE_OID, &image.to_bytes())
            .to_hyphenated()
            .to_string();
        let mut path = PathBuf::new();
        path.push(prefix);
        path.push(base_name);
        path.set_extension("jpg");
        image.save(&path)?;
        Ok(path.to_str().ok_or(DichroismError::ImageWrite)?.to_string())
    }
}

pub struct NewProductImages {
    original: String,
    fullsize: String,
    base: String,
    thumbnail: String,
}

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

    const TEST_DATA_URI: &str = include_str!("unit_test_data/img_data_uri.txt");
    const TEST_DATA_BASE64: &str = include_str!("unit_test_data/test_data_base64.txt");

    #[test]
    fn test_gen_product_images() {
        NewProductImageData::from_data_uri(TEST_DATA_URI.trim())
            .unwrap()
            .commit(".")
            .unwrap();
    }
}