mod parser;
mod version;
mod docker;
mod manifest;
mod dockerfile;
mod metrics;
mod db;
mod registry;

use crate::version::{VersionPattern, CompareOutcome};
use crate::docker::DockerRef;
use crate::manifest::ManifestFile;
use crate::dockerfile::DockerfileFile;
use crate::db::{Db, SqliteDb};
use crate::registry::{Registry, HttpRegistry, AuthInfo, basic_auth};

use rand::distr::{Alphanumeric, SampleString};
use std::ops::Range;
use std::io::Read;
use std::io::Seek;
use std::io::Write;

fn help(cmd: &str) {
    println!(
        "{} [options] [--] <FILE>
Search FILE for docker images and suggest updates

Options:
--auth <REGISTRY> <USER> <PASS> Authenticate against REGISTRY (repeatable)
--config <PATH>                 Read config from PATH
--scratch <DIR>                 Store temporary files in DIR
--metrics-port <PORT>           Serve Prometheus metrics on PORT (default: disabled)",
        cmd
    );
}

struct Repository {
    url: String,
    key: Option<std::path::PathBuf>,
    host: Option<std::path::PathBuf>,
    dest: std::path::PathBuf,
}



#[derive(Debug)]
struct FilePatch {
    position: Range<usize>,
    content: String,
}


fn update_images(db: &dyn Db, reg: &dyn Registry, file: &str, img: DockerRef, edits: &mut Vec<FilePatch>) -> Result<(), String> {
    let registry = img.registry.map(|x| &file[x]).unwrap_or("registry.hub.docker.com");
    let mut tag = img.tag.as_ref().map(|x| file[x.clone()].to_string());
    let image = &file[img.image.clone()];

    metrics::get().images_checked.with_label_values(&[registry]).inc();

    let now = chrono::offset::Utc::now();
    let cache_max_age = chrono::Duration::hours(24);

    let (image_id, last_checked) = match db.get_image(registry, image) {
        Some(x) => x,
        None => {
            let id = db.insert_image(registry, image, now);
            (id, now)
        },
    };

    let cache_stale = now - last_checked > cache_max_age;

    let cached_tags: Vec<String> = db.get_tags_sorted(image_id);

    let (tags, cached_digest): (Vec<String>, Option<String>) = if cache_stale {
        println!("Invalid in cache");
        let mut fetched_tags = reg.get_tags(registry, image)
            .ok_or_else(|| format!("image not found: {}", image))?;

        fetched_tags.sort();
        let mut existing = cached_tags.iter().peekable();
        for t in &fetched_tags {
            while existing.peek().is_some_and(|e| *e < t) {
                let gone = existing.next().unwrap();
                db.delete_tag(image_id, gone);
            }
            if existing.peek() == Some(&t) {
                existing.next();
            } else {
                db.insert_tag(image_id, t, now);
            }
        }
        for gone in existing {
            db.delete_tag(image_id, gone);
        }
        db.update_last_checked(image_id, now);

        (fetched_tags, None)
    } else {
        println!("Valid in cache");
        let tag_for_digest = tag.as_deref().unwrap_or("latest");
        let digest = db.get_tag_digest(image_id, tag_for_digest);

        (cached_tags, digest)
    };

    if let Some(ref tag_str) = tag {
        let mut current = VersionPattern::parse(&tag_str);
        let mut new_tag = None;

        for candidate_str in &tags {
            let candidate = VersionPattern::parse(&candidate_str);
            match current.compare(&candidate) {
                CompareOutcome::Higher => {
                    new_tag = Some(candidate_str.clone());
                    current = candidate;
                },
                CompareOutcome::Lower => {},
                CompareOutcome::Incompatible => {},
                CompareOutcome::Identical => {},
            }
        }

        if let Some(new_tag) = new_tag {
            tag = Some(new_tag.clone());
            edits.push(FilePatch {
                position: img.tag.unwrap(),
                content: new_tag,
            });
            metrics::get().images_updated.with_label_values(&[registry]).inc();
        }
    }

    if let Some(ref digest) = img.digest {
        let tag_for_digest = tag.as_deref().unwrap_or("latest");

        let digest_string = match cached_digest {
            Some(d) => d,
            None => {
                let fetched = reg.get_digest(registry, image, tag_for_digest)
                    .ok_or_else(|| format!("digest not found for {}:{}", image, tag_for_digest))?;

                db.update_tag_digest(image_id, tag_for_digest, &fetched, now);

                fetched
            }
        };

        if file[digest.clone()] != digest_string {
            edits.push(FilePatch {
                position: img.digest.unwrap(),
                content: digest_string,
            });
            metrics::get().images_updated.with_label_values(&[registry]).inc();
        }
    }

    return Ok(());
}

enum Output {
    Overlay(std::fs::File, std::path::PathBuf, std::path::PathBuf),
    Stdout(std::io::Stdout),
}

impl Output {
    fn overlay_file(infile_path: &std::path::Path) -> Self {
        loop {
            let mut filename = std::ffi::OsString::new();
            filename.push(infile_path.file_name().unwrap());
            filename.push(std::ffi::OsStr::new(".edit"));
            filename.push(Alphanumeric.sample_string(&mut rand::rng(), 16));
            let outfile_path = Some(infile_path.parent().unwrap().join(filename));
            if let Ok(output_file) = std::fs::File::create_new(outfile_path.as_ref().unwrap()) {
                return Output::Overlay(output_file, outfile_path.unwrap().into(), infile_path.into());
            }
        }
    }

    fn commit(&mut self) {
        match self {
            Output::Overlay(_, outfile_path, infile_path) => {
                std::fs::remove_file(&infile_path).unwrap();
                std::fs::rename(&outfile_path, &infile_path).unwrap();
            }
            Output::Stdout(_) => {}
        }
    }
}

impl std::ops::Deref for Output {
    type Target = dyn Write;

    fn deref(&self) -> &Self::Target {
        match self {
            Output::Overlay(file, _, _) => file,
            Output::Stdout(stdout) => stdout,
        }
    }
}

impl std::ops::DerefMut for Output {
    fn deref_mut(&mut self) -> &mut Self::Target {
        match self {
            Output::Overlay(file, _, _) => file,
            Output::Stdout(stdout) => stdout,
        }
    }
}

impl std::io::Write for Output {
    fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
        return (**self).write(buf);
    }

    fn flush(&mut self) -> std::io::Result<()> {
        return (**self).flush();
    }

    fn write_vectored(&mut self, bufs: &[std::io::IoSlice<'_>]) -> std::io::Result<usize> {
        return (**self).write_vectored(bufs);
    }

    fn write_all(&mut self, buf: &[u8]) -> std::io::Result<()> {
        return (**self).write_all(buf);
    }

    fn write_fmt(&mut self, args: std::fmt::Arguments<'_>) -> std::io::Result<()> {
        return (**self).write_fmt(args);
    }
}

fn is_dockerfile(path: &std::path::Path) -> bool {
    if let Some(name) = path.file_name() {
        if let Some(name) = name.to_str() {
            return name == "Dockerfile" || name == "dockerfile";
        }
    }
    return false;
}

fn is_yaml(path: &std::path::Path) -> bool {
    if let Some(ext) = path.extension() {
        if let Some(ext) = ext.to_str() {
            return ext == "yaml";
        }
    }
    return false;
}

fn run_tool(db: &dyn Db, reg: &dyn Registry, repos: &Vec<Repository>, mut infile_paths: Vec<std::path::PathBuf>, overwrite: bool) {
    for repo in repos {
        if repo.dest.exists() {
            let mut gitcmd = std::process::Command::new("git");

            gitcmd
                .arg("-C")
                .arg(&repo.dest)
                .arg("fetch")
                .arg("origin");

            if let Some(key) = &repo.key && let Some(host) = &repo.host {
                gitcmd.env("GIT_SSH_COMMAND", format!("ssh -F none -o IdentitiesOnly=yes -o UserKnownHostsFile=\"{}\" -i \"{}\"", host.to_str().unwrap(), key.to_str().unwrap()));
            }
            let exit = gitcmd.status()
                .expect("Git command failed");
            if !exit.success() {
                panic!("Git exited with failure");
            }

            let mut gitcmd = std::process::Command::new("git");

            gitcmd
                .arg("-C")
                .arg(&repo.dest)
                .arg("reset")
                .arg("--hard")
                .arg("@{u}");

            let exit = gitcmd.status()
                .expect("Git command failed");
            if !exit.success() {
                panic!("Git exited with failure");
            }

            let mut gitcmd = std::process::Command::new("git");

            gitcmd
                .arg("-C")
                .arg(&repo.dest)
                .arg("clean")
                .arg("--force")
                .arg("-d")
                .arg("-x");

            let exit = gitcmd.status()
                .expect("Git command failed");
            if !exit.success() {
                panic!("Git exited with failure");
            }
        } else {
            let mut gitcmd = std::process::Command::new("git");
            println!("Cloning {}", repo.url);

            gitcmd
                .arg("clone")
                .arg(&repo.url)
                .arg(&repo.dest);

            if let Some(key) = &repo.key && let Some(host) = &repo.host {
                gitcmd.env("GIT_SSH_COMMAND", format!("ssh -F none -o IdentitiesOnly=yes -o UserKnownHostsFile=\"{}\" -i \"{}\"", host.to_str().unwrap(), key.to_str().unwrap()));
            }

            let exit = gitcmd.status()
                .expect("Git command failed");
            if !exit.success() {
                panic!("Git exited with failure");
            }
        }

        infile_paths.push(repo.dest.clone());
    }

    let mut inpaths = vec![];
    for infile_path in infile_paths {
        if infile_path.is_dir() {
            let mut unsearched = vec![infile_path.clone()];

            while let Some(next) = unsearched.pop() {
                for child in next.read_dir().unwrap() {
                    let child = child.unwrap();
                    let path = child.path();

                    let ft = child.file_type().unwrap();
                    if ft.is_dir() {
                        unsearched.push(path);
                        continue;
                    }

                    if is_yaml(&path) || is_dockerfile(&path) {
                        inpaths.push(path);
                    }
                }
            }
        } else {
            inpaths.push(infile_path);
        };
    }

    for infile_path in inpaths {
        let mut file = std::fs::File::open(&infile_path).unwrap();
        let mut file_content = String::new();
        file.read_to_string(&mut file_content).unwrap();

        let images: Vec<std::ops::Range<usize>> = if is_dockerfile(&infile_path) {
            DockerfileFile::parse(&file_content).image_refs
        } else {
            ManifestFile::parse(&file_content).image_tags
        };

        let mut failed = None;

        let mut edits = vec![];
        for ref image in images {
            println!("Checking image {}", &file_content[image.clone()]);
            let image_ref = DockerRef::parse(&file_content, image);
            if let Err(msg) = update_images(db, reg, &file_content, image_ref, &mut edits) {
                failed = Some(msg);
                break;
            }
        }

        if let Some(msg) = failed {
            println!("{}: {} ", infile_path.display(), msg);
            continue;
        }

        let mut out = if overwrite {
            Output::overlay_file(&infile_path)
        } else {
            Output::Stdout(std::io::stdout())
        };

        let mut current_position = 0;
        file.seek(std::io::SeekFrom::Start(0)).unwrap();
        let mut file_block = file.take(0);
        for edit in edits {
            if edit.position.start > current_position {
                file_block.set_limit((edit.position.start - current_position) as u64);
                std::io::copy(&mut file_block, &mut out).unwrap();
            }

            out.write_all(edit.content.as_bytes()).unwrap();

            // We should have been able to just seek to the position.end here, but that doesn't work
            // for whatever reason. What we can do is calculate the amount to skip ahead, and then do
            // that.
            let skip = (edit.position.end - edit.position.start) as i64;
            file_block.set_limit(skip as u64);
            file_block.seek(std::io::SeekFrom::Current(skip)).unwrap();
            current_position = edit.position.end;
        }

        file_block.set_limit(u64::MAX);
        std::io::copy(&mut file_block, &mut out).unwrap();

        out.commit();
    }

    for repo in repos {
        let mut gitcmd = std::process::Command::new("git");

        gitcmd
            .arg("-c")
            .arg("user.name=vbump")
            .arg("-c")
            .arg("user.email=jesper@jnsn.dev")
            .arg("-C")
            .arg(&repo.dest)
            .arg("commit")
            .arg("--all")
            .arg("--message")
            .arg("Update versions");

        let exit = gitcmd.status()
            .expect("Git command failed");
        if !exit.success() {
            metrics::get().git_operations.with_label_values(&["commit", "failure"]).inc();
            println!("Commit failed, presumably there were no changes");
            continue;
        }
        metrics::get().git_operations.with_label_values(&["commit", "success"]).inc();

        let mut gitcmd = std::process::Command::new("git");
        gitcmd
            .arg("-C")
            .arg(&repo.dest)
            .arg("push")
            .arg("origin")
            .arg("+HEAD:version-bump");

        if let Some(key) = &repo.key && let Some(host) = &repo.host {
            gitcmd.env("GIT_SSH_COMMAND", format!("ssh -F none -o IdentitiesOnly=yes -o UserKnownHostsFile=\"{}\" -i \"{}\"", host.to_str().unwrap(), key.to_str().unwrap()));
        }

        let exit = gitcmd.status()
            .expect("Git command failed");
        if !exit.success() {
            metrics::get().git_operations.with_label_values(&["push", "failure"]).inc();
            panic!("Git exited with failure");
        }
        metrics::get().git_operations.with_label_values(&["push", "success"]).inc();
    }
}

fn main() {
    let argv: Vec<String> = std::env::args().collect();
    let mut it = argv.iter();
    let cmd = &it.next().unwrap();

    let mut auths = vec![];
    let mut positional: Vec<&str> = vec!();
    let mut overwrite = false;
    let mut config_path = None;
    let mut scratch_path = None;
    let mut continuous = false;
    let mut metrics_port: Option<u16> = None;

    loop {
        match it.next().map(|x| x.as_str()) {
            None => break,
            Some("--auth") => {
                if let Some(registry) = it.next() && let Some(username) = it.next() && let Some(password) = it.next() {
                    auths.push(AuthInfo {
                        host: registry.clone(),
                        auth: basic_auth(username, password),
                    });
                } else {
                    println!("Error: --auth requires three parameters");
                    help(cmd);
                    std::process::exit(1);
                }
            },
            Some("--config") => {
                if let Some(path) = it.next() {
                    config_path = Some(std::path::PathBuf::from(path));
                } else {
                    println!("Error: --config requires an parameters");
                    help(cmd);
                    std::process::exit(1);
                }
            },
            Some("--scratch") => {
                if let Some(path) = it.next() {
                    scratch_path = Some(std::path::PathBuf::from(path));
                } else {
                    println!("Error: --scratch requires an parameters");
                    help(cmd);
                    std::process::exit(1);
                }
            },
            Some("--continuous") => {
                continuous = true;
            },
            Some("--metrics-port") => {
                if let Some(port_str) = it.next() {
                    match port_str.parse::<u16>() {
                        Ok(port) => metrics_port = Some(port),
                        Err(_) => {
                            println!("Error: --metrics-port requires a valid port number");
                            help(cmd);
                            std::process::exit(1);
                        }
                    }
                } else {
                    println!("Error: --metrics-port requires a parameter");
                    help(cmd);
                    std::process::exit(1);
                }
            },
            Some("-i") | Some("--inplace") => {
                overwrite = true;
            },
            Some("-h") | Some("--help") => {
                help(cmd);
                std::process::exit(0);
            },
            Some(arg) => positional.push(arg),
        };
    }

    let mut infile_paths = vec![];
    if positional.len() < 1 {
        panic!("BAD ARGUMENTS");
    }

    let sqlite_db = SqliteDb::new(&std::path::PathBuf::from(positional[0]));
    if positional.len() > 1 {
        infile_paths.push(std::path::PathBuf::from(positional[1]));
    }

    let mut repos = vec![];

    let workdir = std::env::current_dir().unwrap();
    if let Some(config_path) = config_path {
        if !config_path.is_dir() {
            println!("config is not a directory");
            std::process::exit(1);
        }

        let mut unsearched = vec![config_path];

        while let Some(next) = unsearched.pop() {
            for child in next.read_dir().unwrap() {
                let child = child.unwrap();
                let path = child.path();

                let ft = child.file_type().unwrap();
                if ft.is_dir() {
                    unsearched.push(path);
                    continue;
                }

                if let Some(name) = path.file_name() {
                    match name.to_str() {
                        Some(".dockerconfigjson") => {
                            let file = std::fs::File::open(&path).unwrap();
                            let mut reader = json_event_parser::ReaderJsonParser::new(file);

                            match reader.parse_next() {
                                Ok(json_event_parser::JsonEvent::StartObject) => {},
                                _ => panic!("Invalid config json"),
                            }

                            match reader.parse_next() {
                                Ok(json_event_parser::JsonEvent::ObjectKey(k)) if &k == "auths" => {},
                                _ => panic!("Invalid config json"),
                            }

                            match reader.parse_next() {
                                Ok(json_event_parser::JsonEvent::StartObject) => {},
                                _ => panic!("Invalid config json"),
                            }

                            let mut possible_key = reader.parse_next();
                            while let Ok(json_event_parser::JsonEvent::ObjectKey(k)) = possible_key {
                                let key = k.into_owned();

                                match reader.parse_next() {
                                    Ok(json_event_parser::JsonEvent::StartObject) => {},
                                    _ => panic!("Invalid config json"),
                                }

                                match reader.parse_next() {
                                    Ok(json_event_parser::JsonEvent::ObjectKey(k)) if &k == "auth" => {},
                                    _ => panic!("Invalid config json"),
                                }

                                match reader.parse_next() {
                                    Ok(json_event_parser::JsonEvent::String(v)) => {
                                        auths.push(AuthInfo {
                                            host: key,
                                            auth: v.into_owned(),
                                        });
                                    },
                                    _ => panic!("Invalid config json"),
                                }

                                match reader.parse_next() {
                                    Ok(json_event_parser::JsonEvent::EndObject) => {},
                                    _ => panic!("Invalid config json"),
                                }

                                possible_key = reader.parse_next();
                            }

                            match possible_key {
                                Ok(json_event_parser::JsonEvent::EndObject) => {},
                                _ => panic!("Invalid config json"),
                            }

                            match reader.parse_next() {
                                Ok(json_event_parser::JsonEvent::EndObject) => {},
                                _ => panic!("Invalid config json"),
                            }
                        }
                        Some("repository") => {
                            let file = std::fs::File::open(&path).unwrap();
                            let mut reader = json_event_parser::ReaderJsonParser::new(file);

                            match reader.parse_next() {
                                Ok(json_event_parser::JsonEvent::StartObject) => {},
                                _ => panic!("Invalid config json"),
                            }

                            match reader.parse_next() {
                                Ok(json_event_parser::JsonEvent::ObjectKey(k)) if &k == "repositories" => {},
                                _ => panic!("Invalid config json"),
                            }

                            match reader.parse_next() {
                                Ok(json_event_parser::JsonEvent::StartObject) => {},
                                _ => panic!("Invalid config json"),
                            }

                            let mut possible_key = reader.parse_next();
                            while let Ok(json_event_parser::JsonEvent::ObjectKey(k)) = possible_key {
                                let k = k.into_owned();
                                match reader.parse_next() {
                                    Ok(json_event_parser::JsonEvent::StartObject) => {},
                                    _ => panic!("Invalid config json"),
                                }

                                match reader.parse_next() {
                                    Ok(json_event_parser::JsonEvent::ObjectKey(k)) if &k == "key" => {},
                                    _ => panic!("Invalid config json"),
                                }

                                let key_name = match reader.parse_next() {
                                    Ok(json_event_parser::JsonEvent::String(v)) => {
                                        v.into_owned()
                                    },
                                    _ => panic!("Invalid config json"),
                                };

                                match reader.parse_next() {
                                    Ok(json_event_parser::JsonEvent::ObjectKey(k)) if &k == "host" => {},
                                    _ => panic!("Invalid config json"),
                                }

                                let host_name = match reader.parse_next() {
                                    Ok(json_event_parser::JsonEvent::String(v)) => {
                                        v.into_owned()
                                    },
                                    _ => panic!("Invalid config json"),
                                };

                                match reader.parse_next() {
                                    Ok(json_event_parser::JsonEvent::ObjectKey(k)) if &k == "dest" => {},
                                    _ => panic!("Invalid config json"),
                                }

                                let dest = match reader.parse_next() {
                                    Ok(json_event_parser::JsonEvent::String(v)) => {
                                        v.into_owned()
                                    },
                                    _ => panic!("Invalid config json"),
                                };

                                match reader.parse_next() {
                                    Ok(json_event_parser::JsonEvent::EndObject) => {},
                                    _ => panic!("Invalid config json"),
                                }

                                repos.push(Repository {
                                    url: k,
                                    key: Some(workdir.join(path.parent().unwrap().join(std::path::PathBuf::from(key_name)))),
                                    host: Some(workdir.join(path.parent().unwrap().join(std::path::PathBuf::from(host_name)))),
                                    dest: scratch_path.as_ref().unwrap().join(dest),
                                });

                                possible_key = reader.parse_next();
                            }

                            match possible_key {
                                Ok(json_event_parser::JsonEvent::EndObject) => {},
                                _ => panic!("Invalid config json"),
                            }

                            match reader.parse_next() {
                                Ok(json_event_parser::JsonEvent::EndObject) => {},
                                _ => panic!("Invalid config json"),
                            }
                        }
                        Some(_) | None => {}
                    }
                }
            }
        }
    }

    let registry = HttpRegistry::new(auths);

    metrics::init();
    metrics::get().state.set(metrics::STATE_IDLE);
    if let Some(port) = metrics_port {
        metrics::serve(port);
    }

    loop {
        metrics::get().state.set(metrics::STATE_ACTIVE);
        let run_start = std::time::Instant::now();

        run_tool(&sqlite_db, &registry, &repos, infile_paths.clone(), overwrite);

        let run_duration = run_start.elapsed().as_secs_f64();
        metrics::get().run_duration.set(run_duration);
        metrics::get().state.set(metrics::STATE_IDLE);

        if !continuous { break; }

        println!("Waiting for next run");
        std::thread::sleep(std::time::Duration::from_hours(24));
    }
}