use anyhow::Result;
use clap::{Parser, ValueHint};
use dialoguer::theme::ColorfulTheme;
use dialoguer::Confirm;
use image::DynamicImage;
use indicatif::{ProgressBar, ProgressStyle};
use log::*;
use pdf_writer::{Content, Filter, Finish, Name, Pdf, Rect, Ref};
use rayon::prelude::*;
use std::ffi::OsStr;
use std::fs::File;
use std::io::Read;
use std::path::{Path, PathBuf};
use std::time::Duration;
use tabled::builder::Builder;
use tabled::settings::Style;
use walkdir::WalkDir;
use zip::ZipArchive;

#[derive(Parser)]
#[command()]
struct Cli {
    #[arg(
        short = 'i',
        long = "input",
        value_hint = ValueHint::FilePath,
        help = "Path to CBZ file or directory containing CBZ files"
    )]
    input_path: String,

    #[arg(
        short = 'o',
        long = "output-directory",
        default_value = ".",
        value_hint = ValueHint::FilePath,
        help = "Output directory for PDF files"
    )]
    output_dir: String,

    #[arg(short = 'p', long, help = "Ask for confirmation before doing anything")]
    interactive: bool,
}

fn main() -> Result<(), Box<dyn std::error::Error>> {
    pretty_env_logger::init();

    let cli = Cli::parse();

    let input_path = Path::new(&cli.input_path);
    let output_dir = Path::new(&cli.output_dir);

    let mut jobs = Vec::new();

    if input_path.is_file() && input_path.extension() == Some(OsStr::new("cbz")) {
        jobs.push(Job::new(input_path.to_path_buf(), output_dir.to_path_buf()));
    } else if input_path.is_dir() {
        jobs.extend(walk_directory(input_path, output_dir));
    } else {
        eprintln!(
            "Invalid input path. Please provide a CBZ file or a directory containing CBZ files."
        );
        std::process::exit(1);
    }

    jobs.sort_by_key(|j| j.cbz_path.clone().into_os_string().into_string());

    let proceed = if cli.interactive {
        let mut table_builder = Builder::default();
        table_builder.push_record(["From", "To"]);
        jobs.iter().for_each(|job| {
            table_builder.push_record(vec![
                job.cbz_path.clone().into_os_string().into_string().unwrap(),
                job.pdf_path.clone().into_os_string().into_string().unwrap(),
            ]);
        });

        let mut table = table_builder.build();
        table.with(Style::rounded());

        println!("{}", table);

        Confirm::with_theme(&ColorfulTheme::default())
            .with_prompt("Convert?")
            .interact()?
    } else {
        true
    };

    if proceed {
        process_jobs(jobs)?;
    }

    Ok(())
}

fn walk_directory(directory: &Path, output_dir: &Path) -> Vec<Job> {
    debug!("Walking {:?}", directory);
    let mut jobs = Vec::new();
    for entry in WalkDir::new(directory) {
        let entry = entry.unwrap();
        let path = entry.path();
        if path.is_file() && path.extension() == Some(OsStr::new("cbz")) {
            jobs.push(Job::new(path.to_path_buf(), output_dir.to_path_buf()));
        }
    }

    jobs
}

struct ImageFile {
    pub name: String,
    pub data: Vec<u8>,
}

struct DecodedImageFile {
    pub name: String,
    pub data: Vec<u8>,
    pub image: DynamicImage,
}

impl From<&ImageFile> for DecodedImageFile {
    fn from(value: &ImageFile) -> Self {
        let image = image::load_from_memory(&value.data).unwrap();
        Self {
            name: value.name.clone(),
            data: value.data.clone(),
            image,
        }
    }
}

struct Job {
    pub cbz_path: PathBuf,
    pub pdf_path: PathBuf,
}

impl Job {
    fn new(cbz_path: PathBuf, output_dir: PathBuf) -> Self {
        let mut output_path = output_dir.join(cbz_path.file_name().unwrap());
        output_path.set_extension("pdf");

        Self {
            cbz_path,
            pdf_path: output_path,
        }
    }
}

fn convert_cbz(cbz_path: &Path, output_path: &Path) -> Result<()> {
    let a4 = Rect::new(0.0, 0.0, 595.0, 842.0);

    let mut zip = ZipArchive::new(File::open(cbz_path)?)?;
    let mut files = Vec::new();
    for i in 0..zip.len() {
        let mut file = zip.by_index(i)?;
        let mut image_data = Vec::new();
        let name = file.enclosed_name().expect("Failed to read file name");
        if name.extension() == Some(OsStr::new("jpg")) {
            file.read_to_end(&mut image_data)?;
            files.push(ImageFile {
                name: name
                    .file_name()
                    .expect("Failed to read file name")
                    .to_string_lossy()
                    .to_string(),
                data: image_data,
            });
        }
    }

    let mut images = Vec::new();
    files
        .par_iter()
        .map(DecodedImageFile::from)
        .collect_into_vec(&mut images);
    images.par_sort_by_key(|img| img.name.clone());

    let mut pdf = Pdf::new();
    let catalog_id = Ref::new(1);
    let page_tree_id = Ref::new(2);
    pdf.catalog(catalog_id).pages(page_tree_id);

    let mut pages = Vec::new();
    let image_count = images.len();

    for (pos, image) in images.iter().enumerate() {
        let page_id = Ref::new(pos as i32 + 10);
        let image_id = Ref::new(image_count as i32 + 10 + pos as i32);
        let content_id = Ref::new(image_count as i32 * 3 + 10 + pos as i32);
        pages.push(page_id);
        let mut page = pdf.page(page_id);
        let image_name = Name(b"Im1");

        page.media_box(a4);
        page.parent(page_tree_id);
        page.contents(content_id);
        page.resources().x_objects().pair(image_name, image_id);
        page.finish();

        let mut pdf_image = pdf.image_xobject(image_id, &image.data);
        pdf_image.filter(Filter::DctDecode);
        pdf_image.width(image.image.width() as i32);
        pdf_image.height(image.image.height() as i32);
        pdf_image.color_space().device_rgb();
        pdf_image.bits_per_component(8);
        pdf_image.finish();

        let mut content = Content::new();
        content.save_state();
        content.transform([a4.x2, 0.0, 0.0, a4.y2, 0.0, 0.0]);
        content.x_object(image_name);
        content.restore_state();
        pdf.stream(content_id, &content.finish());
    }

    let page_count = pages.len();
    pdf.pages(page_tree_id).kids(pages).count(page_count as i32);

    std::fs::write(output_path, pdf.finish())?;

    Ok(())
}

fn process_jobs(jobs: Vec<Job>) -> Result<()> {
    let pb = ProgressBar::new(jobs.len() as u64);
    pb.enable_steady_tick(Duration::from_millis(300));
    pb.set_style(ProgressStyle::with_template(
        "[{elapsed_precise}] {wide_bar} {pos:>7}/{len:7} {msg}",
    )?);

    jobs.par_iter().for_each(|entry| {
        convert_cbz(&entry.cbz_path, &entry.pdf_path).unwrap();
        pb.inc(1);
    });

    pb.finish();
    Ok(())
}