#![feature(path_add_extension)]

mod collect_files;
mod config;
mod generate_html;
mod generate_rss;
mod string_utils;

pub use collect_files::*;
pub use config::*;
pub use generate_html::*;
pub use generate_rss::*;
pub use string_utils::*;

use markdown::*;
use vagabond::*;

use std::collections::HashSet;
use std::time::SystemTime;

use log::{info, warn, error, fatal};
use switchboard::*;


fn main() {
    let mut args = Switchboard::from_env();

    // Informational switches.
    args.named("help").short('h');
    args.named("version");
    args.named("verbose").short('v');
    if args.get("help").as_bool() {
        print_help();
        std::process::exit(0);
    }
    if args.get("version").as_bool() {
        let version = env!("CARGO_PKG_VERSION");
        eprintln!("toaster, version {version}");
        eprintln!("written by ben bridle");
        std::process::exit(0);
    }
    if args.get("verbose").as_bool() {
        log::set_log_level(log::LogLevel::Info);
    }

    // Functional switches.
    args.positional("source");
    args.positional("destination");
    args.named("delete");
    args.named("html");
    args.named("use-symlinks");
    args.raise_errors();
    let source = args.get("source").as_path();
    let destination = args.get("destination").as_path();
    let delete_existing = args.get("delete").as_bool();
    let export_html = args.get("html").as_bool();
    let use_symlinks = args.get("use-symlinks").as_bool();
    #[cfg(not(target_family = "unix"))]
    if use_symlinks {
        fatal!("Symbolic links are only supported on Linux");
    }

    // Parse entire website directory.
    let source = match source.canonicalize() {
        Ok(source) => source,
        Err(err) => fatal!("{source:?}: {err}"),
    };
    let website = Website::from_path(&source);

    // ------------------------------------------------------------

    // Check for duplicate output paths for pages.
    let mut urls: HashSet<&str> = HashSet::new();
    let mut duplicates: HashSet<&str> = HashSet::new();
    for page in &website.pages {
        if !urls.insert(&page.url) {
            duplicates.insert(&page.url);
        };
    }
    for static_file in &website.static_files {
        if !urls.insert(&static_file.url) {
            duplicates.insert(&static_file.url);
        };
    }
    for redirect in &website.redirects {
        if !urls.insert(&redirect.url) {
            duplicates.insert(&redirect.url);
        };
    }
    if !duplicates.is_empty() {
        for destination in duplicates {
            warn!("Multiple files, pages, or redirects have the output path {destination:?}");
            for page in &website.pages {
                if page.url == destination {
                    eprintln!(":: {:?}", page.source_path);
                }
            }
            for static_file in &website.static_files {
                if static_file.url == destination {
                    eprintln!(":: {:?}", static_file.source_path);
                }
            }
            for redirect in &website.redirects {
                if redirect.url == destination {
                    eprintln!(":: {:?}", redirect.source_path);
                }
            }
        }
    }

    let mut destination = destination;
    destination.push(&website.name.slug());

    if delete_existing && Entry::from_path(&destination).is_ok() {
        info!("Deleting existing destination directory {destination:?}");
        remove(&destination).unwrap_or_else(|_|
            error!("Failed to delete existing destination directory {destination:?}"));
    }


    for page in &website.pages {
        let mut destination = destination.clone();
        destination.push(&page.url);
        // Convert document to different formats.
        if export_html {
            let html = generate_html(page, &website);
            write_file(&html, &destination, "html", page.last_modified);
        }
        // Copy original markdown file.
        destination.add_extension("md");
        info!("Copying original markdown file to {destination:?}");
        copy(&page.source_path, &destination).unwrap_or_else(|_|
            error!("Failed to copy original markdown file {:?} to {:?}",
                page.source_path, destination));
    }

    for static_file in &website.static_files {
        let mut destination = destination.clone();
        destination.push(&static_file.url);
        if use_symlinks {
            #[cfg(target_family = "unix")]
            {
            info!("Linking static file to {destination:?}");
            make_parent_directory(&destination).unwrap();
            let _ = remove(&destination);
            std::os::unix::fs::symlink(&static_file.source_path, &destination).unwrap_or_else(|_|
                error!("Failed to link static file {:?} to {:?}",
                    static_file.source_path, destination));
            }
        } else {
            info!("Copying static file to {destination:?}");
            copy(&static_file.source_path, &destination).unwrap_or_else(|_|
                error!("Failed to copy static file {:?} to {:?}",
                    static_file.source_path, destination));
        }

    }

    // NOTE: Static dir contents are copied as part of all static files.

    for redirect in &website.redirects {
        let mut destination = destination.clone();
        destination.push(&redirect.url);
        let path = &redirect.target;
        if export_html {
            if !path.contains("://") {
                if let Some(path) = website.has_page(redirect, &path, "html") {
                    write_file(&generate_html_redirect(&path, &website), &destination, "html", redirect.last_modified);
                } else {
                    warn!("Redirect {:?} links to nonexistent page {path:?}", redirect.name);
                }
            } else {
                write_file(&generate_html_redirect(&path, &website), &destination, "html", redirect.last_modified);
            }
        }
    }

    for feed in &website.feeds {
        let mut destination = destination.clone();
        destination.push(&feed.url);
        write_file(&generate_rss(feed, &website), &destination, "rss", feed.last_modified);
    }
}

fn print_help() {
    eprintln!("\
Usage: toaster <source> <destination>

Generate a website from a structured directory of markdown files.

Arguments:
  source               Source directory with markdown files
  destination          Path to output directory

Switches:
  --delete             Delete the destination directory first if it exists
  --html               Generate HTML output
  --version, -v        Print information as each file is parsed
  --version            Print the program version and exit
  --help, -h           Print help
");
}

pub fn write_file(text: &str, destination: &PathBuf, ext: &str, last_modified: Option<SystemTime>) {
    let mut destination = destination.clone();
    destination.add_extension(ext);
    info!("Generating {destination:?}");
    make_parent_directory(&destination).unwrap_or_else(|_|
        error!("Failed to create parent directories for {destination:?}"));
    write_to_file(&destination, text).unwrap_or_else(|_|
        error!("Failed to write generated {ext} file to {destination:?}"));
    // Set the last-modified time of the new file to the time provided.
    if let Some(time) = last_modified {
        if let Ok(dest) = std::fs::File::open(&destination) {
            let _ = dest.set_modified(time);
        }
    }
}