use clap::{CommandFactory, FromArgMatches, Parser};
use git_testament::git_testament;
use log::{debug, error, info};
use riki::error::RikiError;
use riki::git::{git_dirty, git_whatchanged};
use riki::name::Name;
use riki::pagespec;
use riki::site::Site;
use riki::time::parse_timestamp;
use riki::util::{canonicalize, copy_file_from_source, get_mtime, mkdir, set_mtime, write};
use riki::version::Version;
use std::error::Error;
use std::path::{Path, PathBuf};

const ENVLOG: &str = "RIKI_LOG";

git_testament!(VERSION);

fn main() {
    if let Err(err) = real_main() {
        error!("ERROR: {}", err);
        let mut source = err.source();
        while source.is_some() {
            let s = source.unwrap();
            error!("  caused by: {}", s);
            source = source.unwrap().source();
        }
        std::process::exit(1);
    }
}

fn real_main() -> Result<(), RikiError> {
    let env = env_logger::Env::new().filter(ENVLOG);
    env_logger::init_from_env(env);

    info!("riki starts");

    let version = Version::new(&VERSION);
    let short = version.version()?;
    let long = version.long_version()?;

    {
        let argparser = Args::command();
        let argparser = argparser.version(short.as_str());
        let argparser = argparser.long_version(long.as_str());

        let args = argparser.get_matches();
        let args = Args::from_arg_matches(&args).unwrap();
        match args.command {
            Command::Build(cmd) => cmd.run()?,
            Command::List(cmd) => cmd.run()?,
            Command::Timestamps(cmd) => cmd.run()?,
            Command::ParseDate(cmd) => cmd.run()?,
            Command::PageSpec(cmd) => cmd.run()?,
            Command::Links(cmd) => cmd.run()?,
        }
    }

    info!("riki ends OK");
    Ok(())
}

/// Static site generator.
///
/// Riki generates a static web site from markdown files. It mostly
/// follows wikitext and other syntax and semantics of the ikiwiki
/// software (see http://ikiwiki.info/) for input files.
#[derive(Parser)]
struct Args {
    #[clap(subcommand)]
    command: Command,
}

#[derive(Parser)]
enum Command {
    Build(Build),
    List(List),
    Timestamps(Timestamps),
    ParseDate(ParseDate),
    PageSpec(PageSpec),
    Links(Links),
}

/// Build the site.
#[derive(Parser)]
struct Build {
    /// Should the output only have the HTML BODY element or the full
    /// page?
    #[clap(long)]
    plain_body: bool,

    /// Directory where source files are.
    srcdir: PathBuf,

    /// Directore where output files get put. This directory must not
    /// exist before the program is run.
    destdir: PathBuf,
}

impl Build {
    fn run(&self) -> Result<(), RikiError> {
        let srcdir = canonicalize(&self.srcdir)?;
        debug!("srcdir={}", srcdir.display());

        mkdir(&self.destdir)?;
        let destdir = canonicalize(&self.destdir)?;
        debug!("destdir={}", destdir.display());

        let mut site = Site::new(&srcdir, &destdir);
        site.scan()?;
        site.process()?;
        debug!("markdown file count: {}", site.markdown_pages().count());

        for page in site.markdown_pages() {
            let htmlpage = if self.plain_body {
                page.body_to_html()?
            } else {
                page.to_html()?
            };
            let output = page.meta().destination_filename();
            debug!("writing: {}", output.display());
            write(&output, &format!("{}", htmlpage))?;
            set_mtime(&output, page.meta().mtime())?;
        }

        for file in site.files_only() {
            copy_file_from_source(file.source_path(), file.destination_path())?;
        }

        Ok(())
    }
}

/// List source files in the site.
#[derive(Parser)]
struct List {
    /// Directory where source files are.
    srcdir: PathBuf,
}

impl List {
    fn run(&self) -> Result<(), RikiError> {
        let srcdir = canonicalize(&self.srcdir)?;
        let mut site = Site::new(&srcdir, &srcdir);
        site.scan()?;
        let mut names: Vec<&Name> = site.pages_and_files().collect();
        names.sort_by_cached_key(|name| name.page_path());
        for name in names {
            println!("{}", name);
        }
        Ok(())
    }
}

/// Show the timestamp for each source file.
#[derive(Parser)]
struct Timestamps {
    /// Directory where source files are.
    srcdir: PathBuf,
}

impl Timestamps {
    fn run(&self) -> Result<(), RikiError> {
        let srcdir = canonicalize(&self.srcdir)?;
        let mut site = Site::new(&srcdir, &srcdir);
        site.scan()?;
        let mut names: Vec<&Name> = site.pages_and_files().collect();
        names.sort_by_cached_key(|name| name.page_path());

        let whatchanged = git_whatchanged(&srcdir)?;

        let dirty = git_dirty(&srcdir)?;

        println!();
        for name in names {
            let relative = name.source_path().strip_prefix(&srcdir).unwrap();
            if Self::is_dirty(relative, &dirty) {
                println!("dirty: {} {:?}", name, get_mtime(name.source_path())?);
            } else if let Some(timestamp) = whatchanged.get(relative) {
                println!("git: {} {:?}", name, timestamp);
            }
        }
        Ok(())
    }

    fn is_dirty(filename: &Path, dirty: &[PathBuf]) -> bool {
        dirty.iter().any(|x| *x == filename)
    }
}

/// Parse a date string as the 'meta date' directive does.
#[derive(Parser)]
struct ParseDate {
    /// Date strings to parse.
    dates: Vec<String>,
}

impl ParseDate {
    fn run(&self) -> Result<(), RikiError> {
        for date in self.dates.iter() {
            println!("input: {:?}", date);
            let parsed = parse_timestamp(date)?;
            println!("parse: {:?}", parsed);
        }
        Ok(())
    }
}

/// List the pages that match a PageSpec expression.
#[derive(Parser)]
struct PageSpec {
    /// Directory where source files are.
    srcdir: PathBuf,

    /// Path to page that contains the PageSpec.
    path: PathBuf,

    /// PageSpec expression.
    pagespec: String,
}

impl PageSpec {
    fn run(&self) -> Result<(), RikiError> {
        let srcdir = canonicalize(&self.srcdir)?;
        let mut site = Site::new(&srcdir, &PathBuf::from("/tmp"));
        site.scan()?;
        site.process()?;

        let pagespec = pagespec::PageSpec::new(&self.path, &self.pagespec)?;
        debug!("pagespec: {:#?}", pagespec);

        for page in site.markdown_pages() {
            let path = page.meta().path();
            debug!("consider markdown page {}", path.display());
            if pagespec.matches(&site, path) {
                println!("{}", path.display());
            }
        }

        for name in site.files_only() {
            let path = name.page_path();
            debug!("consider file {}", path.display());
            if pagespec.matches(&site, path) {
                println!("{}", path.display());
            }
        }

        Ok(())
    }
}

/// List links in the pages listed on the command line.
#[derive(Parser)]
struct Links {
    /// Directory where source files are.
    srcdir: PathBuf,

    /// Path to pages whose links are to be listed.
    pages: Vec<PathBuf>,
}

impl Links {
    fn run(&self) -> Result<(), RikiError> {
        let srcdir = canonicalize(&self.srcdir)?;
        let mut site = Site::new(&srcdir, &PathBuf::from("/tmp"));
        site.scan()?;
        site.process()?;

        for path in self.pages.iter() {
            if let Some(page) = site.page(path) {
                println!("page: {:?}", page.meta().path().display());
                for path in page.meta().links_to() {
                    println!("  {}", path.display());
                }
            }
        }

        Ok(())
    }
}