use std::path::PathBuf;

use actix::prelude::*;

use kxio::{fs::FileSystem, network::Network};
use tracing::{error, info};

use crate::server::{
    actors::{
        file_watcher::FileUpdated,
        repo::{CloneRepo, RepoActor},
        webhook::{AddWebhookRecipient, ShutdownWebhook, WebhookActor, WebhookRouter},
    },
    config::{
        ForgeConfig, ForgeName, GitDir, RepoAlias, RepoDetails, ServerConfig, ServerRepoConfig,
        ServerStorage, Webhook,
    },
    types::ServerGeneration,
};

#[derive(Debug, derive_more::Display, derive_more::From)]
pub enum Error {
    #[display("Failed to create data directories")]
    FailedToCreateDataDirectory(kxio::fs::Error),

    #[display("The forge data path is not a directory: {path:?}")]
    ForgeDirIsNotDirectory {
        path: PathBuf,
    },

    Config(crate::server::config::Error),

    Io(std::io::Error),
}
type Result<T> = core::result::Result<T, Error>;

pub struct Server {
    generation: ServerGeneration,
    webhook: Option<Addr<WebhookActor>>,
    fs: FileSystem,
    net: Network,
}
impl Actor for Server {
    type Context = Context<Self>;
}
impl Handler<FileUpdated> for Server {
    type Result = ();

    fn handle(&mut self, _msg: FileUpdated, ctx: &mut Self::Context) -> Self::Result {
        let server_config = match ServerConfig::load(&self.fs) {
            Ok(server_config) => server_config,
            Err(err) => {
                error!("Failed to load config file. Error: {}", err);
                return;
            }
        };
        ctx.notify(server_config);
    }
}
impl Handler<ServerConfig> for Server {
    type Result = ();

    #[allow(clippy::cognitive_complexity)] // TODO: (#75) reduce complexity
    fn handle(&mut self, msg: ServerConfig, _ctx: &mut Self::Context) -> Self::Result {
        if let Some(webhook) = self.webhook.take() {
            webhook.do_send(ShutdownWebhook);
        }
        self.generation.inc();
        let server_config = msg;
        // Server Storage
        let dir = server_config.storage().path();
        if !dir.exists() {
            info!(?dir, "server storage doesn't exist - creating it");
            if let Err(err) = self.fs.dir_create(dir) {
                error!(?err, ?dir, "Failed to create server storage");
                return;
            }
        }
        let Ok(canon) = dir.canonicalize() else {
            error!(?dir, "Failed to confirm server storage");
            return;
        };
        info!(dir = ?canon, "server storage");

        // Forge directories in Server Storage
        let server_storage = server_config.storage();
        if let Err(err) = self.create_forge_data_directories(&server_config, dir) {
            error!(?err, "Failure creating forge storage");
            return;
        }

        // Webhook Server
        info!("Starting Webhook Server...");
        let webhook_router = WebhookRouter::new().start();
        let webhook = server_config.webhook();

        // Forge Actors
        for (forge_name, forge_config) in server_config.forges() {
            self.create_forge_repos(forge_config, forge_name.clone(), server_storage, webhook)
                .into_iter()
                .map(|a| self.start_actor(a))
                .map(|(alias, addr)| AddWebhookRecipient(alias, addr.recipient()))
                .for_each(|msg| webhook_router.do_send(msg));
        }

        let webhook = WebhookActor::new(webhook_router.recipient()).start();
        self.webhook.replace(webhook);
    }
}
impl Server {
    pub fn new(fs: FileSystem, net: Network) -> Self {
        let generation = ServerGeneration::new();
        Self {
            generation,
            webhook: None,
            fs,
            net,
        }
    }
    fn create_forge_data_directories(
        &self,
        server_config: &ServerConfig,
        server_dir: &std::path::Path,
    ) -> Result<()> {
        for (forge_name, _forge_config) in server_config.forges() {
            let forge_dir: PathBuf = (&forge_name).into();
            let path = server_dir.join(&forge_dir);
            if self.fs.path_exists(&path)? {
                if !self.fs.path_is_dir(&path)? {
                    return Err(Error::ForgeDirIsNotDirectory { path });
                }
            } else {
                info!(%forge_name, ?path, "creating storage");
                self.fs.dir_create_all(&path)?;
            }
        }

        Ok(())
    }

    fn create_forge_repos(
        &self,
        forge_config: &ForgeConfig,
        forge_name: ForgeName,
        server_storage: &ServerStorage,
        webhook: &Webhook,
    ) -> Vec<(ForgeName, RepoAlias, RepoActor)> {
        let span =
            tracing::info_span!("create_forge_repos", name = %forge_name, config = %forge_config);

        let _guard = span.enter();
        info!("Creating Forge");
        let mut repos = vec![];
        let creator = self.create_actor(forge_name, forge_config.clone(), server_storage, webhook);
        for (repo_alias, server_repo_config) in forge_config.repos() {
            let forge_repo = creator((repo_alias, server_repo_config));
            info!(
                alias = %forge_repo.1,
                "Created Repo"
            );
            repos.push(forge_repo);
        }
        repos
    }

    fn create_actor(
        &self,
        forge_name: ForgeName,
        forge_config: ForgeConfig,
        server_storage: &ServerStorage,
        webhook: &Webhook,
    ) -> impl Fn((RepoAlias, &ServerRepoConfig)) -> (ForgeName, RepoAlias, RepoActor) {
        let server_storage = server_storage.clone();
        let webhook = webhook.clone();
        let net = self.net.clone();
        let generation = self.generation;
        move |(repo_alias, server_repo_config)| {
            let span = tracing::info_span!("create_actor", alias = %repo_alias, config = %server_repo_config);
            let _guard = span.enter();
            info!("Creating Repo");
            let gitdir = server_repo_config.gitdir().map_or_else(
                || {
                    GitDir::from(
                        server_storage
                            .path()
                            .join(forge_name.to_string())
                            .join(repo_alias.to_string()),
                    )
                },
                |gitdir| gitdir,
            );
            // INFO: can't canonicalise gitdir as the path needs to exist to do that and we may not
            //       have cloned the repo yet
            let repo_details = RepoDetails::new(
                generation,
                &repo_alias,
                server_repo_config,
                &forge_name,
                &forge_config,
                gitdir,
            );
            info!("Starting Repo Actor");
            let actor = RepoActor::new(repo_details, webhook.clone(), generation, net.clone());
            (forge_name.clone(), repo_alias, actor)
        }
    }

    fn start_actor(
        &self,
        actor: (ForgeName, RepoAlias, RepoActor),
    ) -> (RepoAlias, Addr<RepoActor>) {
        let (forge_name, repo_alias, actor) = actor;
        let span = tracing::info_span!("start_actor", forge = %forge_name, repo = %repo_alias);
        let _guard = span.enter();
        let addr = actor.start();
        addr.do_send(CloneRepo);
        info!("Started");
        (repo_alias, addr)
    }
}