//! Handle downloads of newspaper issues.

use std::{
    fs::{self},
    io::{Cursor, Read},
    path::Path,
};

use anyhow::Result;
use tracing::{debug, info};

use crate::{nzz::Issue, pdf};

/// Download all pages of the provided `issues` and save them merged to the directory `output_dir`.
///
/// Create `output_dir` if it does not exist.
pub async fn fetch(issues: Vec<Issue>, output_dir: &Path) -> Result<()> {
    debug!("ensuring {output_dir:?} exists");
    fs::create_dir_all(output_dir)?;

    for issue in issues {
        info!("saving issue {}", issue.publication_date);

        let tmp_dir = tempfile::tempdir()?;
        let mut pages = Vec::new();
        for (i, page) in issue.pages.into_iter().enumerate() {
            debug!(
                "fetching issue {}, page {}: {page}",
                issue.publication_date,
                i + 1
            );

            let response = reqwest::Client::new().get(page).send().await?;
            let mut content = Cursor::new(response.bytes().await?);
            let mut page_data = Vec::new();
            content.read_to_end(&mut page_data)?;

            let tmp_page = tmp_dir.path().join(i.to_string());
            fs::write(&tmp_page, page_data)?;
            pages.push(tmp_page);
        }

        let issue_name = format!("nzz_{}.pdf", issue.publication_date);
        let issue_path = output_dir.join(issue_name);
        let issue_title = format!("NZZ {}", issue.publication_date);

        pdf::merge(pages, &issue_path, &issue_title)?;
        debug!("issue {} saved", issue.publication_date);
    }

    Ok(())
}