use std::fmt::Display;

use actix::prelude::*;

use kxio::network;
use tracing::{error, info, warn};

use crate::server::{
    actors::repo::branch,
    config::{self, BranchName},
    forge,
};

use super::{RepoActor, StartMonitoring, StartRepo};

#[tracing::instrument(fields(forge_name = %repo_details.forge.name, repo_name = %repo_details.name), skip_all)]
pub async fn validate_positions(
    repo_details: config::RepoDetails,
    config: config::RepoConfig,
    addr: Addr<RepoActor>,
    net: network::Network,
) {
    let commit_histories = match repo_details.forge.forge_type {
        config::ForgeType::ForgeJo => {
            forge::forgejo::get_commit_histories(&repo_details, &config, &net).await
        }
    };
    let commit_histories = match commit_histories {
        Ok(commit_histories) => commit_histories,
        Err(err) => {
            error!(?err, "Failed to get commit histories");
            return;
        }
    };
    let Some(main) = commit_histories.main.first().cloned() else {
        warn!("No commits on main branch '{}'", config.branches().main());
        return;
    };
    // verify that next is an ancestor of dev, and force update to it main if it isn't
    let Some(next) = commit_histories.next.first().cloned() else {
        warn!("No commits on next branch '{}", config.branches().next());
        return;
    };
    let next_is_ancestor_of_dev = commit_histories.dev.iter().any(|dev| dev == &next);
    if !next_is_ancestor_of_dev {
        info!("Next is not an ancestor of dev - resetting next to main");
        if branch::reset(
            &config.branches().next(),
            main,
            ResetForce::Force(next.into()),
            &repo_details,
        )
        .is_ok()
        {
            addr.do_send(super::ValidateRepo)
        }
        return;
    }

    let next_commits = commit_histories
        .next
        .into_iter()
        .take(2)
        .collect::<Vec<_>>();
    if !next_commits.contains(&main) {
        warn!(
            "Main branch '{}' is not on the same commit as next branch '{}', or it's parent",
            config.branches().main(),
            config.branches().next()
        );
        return;
    }
    let Some(next) = next_commits.first().cloned() else {
        warn!("No commits on next branch '{}'", config.branches().next());
        return;
    };
    let dev_has_next = commit_histories
        .dev
        .iter()
        .any(|commit| commit == &next_commits[0]);
    if !dev_has_next {
        warn!(
            "Dev branch '{}' is not based on next branch '{}'",
            config.branches().dev(),
            config.branches().next()
        );
        return; // dev is not based on next
    }
    let dev_has_main = commit_histories.dev.iter().any(|commit| commit == &main);
    if !dev_has_main {
        warn!(
            "Dev branch '{}' is not based on main branch '{}'",
            config.branches().dev(),
            config.branches().main()
        );
        return;
    }
    let Some(dev) = commit_histories.dev.first().cloned() else {
        warn!("No commits on dev branch '{}'", config.branches().dev());
        return;
    };
    addr.do_send(StartMonitoring {
        main,
        next,
        dev,
        dev_commit_history: commit_histories.dev,
    });
}

// advance next to the next commit towards the head of the dev branch
#[tracing::instrument(fields(next), skip_all)]
pub async fn advance_next(
    next: forge::Commit,
    dev_commit_history: Vec<forge::Commit>,
    repo_details: config::RepoDetails,
    repo_config: config::RepoConfig,
    addr: Addr<RepoActor>,
) {
    let next_commit = find_next_commit_on_dev(next, dev_commit_history);
    let Some(commit) = next_commit else {
        warn!("No commits to advance next to");
        return;
    };
    match reset(
        &repo_config.branches().next(),
        commit,
        ResetForce::Normal,
        &repo_details,
    ) {
        Ok(_) => {
            info!("Success");
            addr.do_send(StartRepo);
        }
        Err(err) => {
            warn!(?err, "Failed")
        }
    };
}

fn find_next_commit_on_dev(
    next: forge::Commit,
    dev_commit_history: Vec<forge::Commit>,
) -> Option<forge::Commit> {
    let mut next_commit: Option<forge::Commit> = None;
    for commit in dev_commit_history.into_iter() {
        if commit == next {
            break;
        };
        next_commit.replace(commit);
    }
    next_commit
}

// advance main branch to the commit 'next'
#[tracing::instrument(fields(next), skip_all)]
pub async fn advance_main(
    next: forge::Commit,
    repo_details: config::RepoDetails,
    repo_config: config::RepoConfig,
    addr: Addr<RepoActor>,
) {
    match reset(
        &repo_config.branches().main(),
        next,
        ResetForce::Normal,
        &repo_details,
    ) {
        Ok(_) => {
            info!("Success");
            addr.do_send(StartRepo);
        }
        Err(err) => {
            warn!(?err, "Failed")
        }
    };
}

#[derive(Clone)]
pub struct GitRef(pub String);
impl From<forge::Commit> for GitRef {
    fn from(value: forge::Commit) -> Self {
        Self(value.sha)
    }
}
impl From<BranchName> for GitRef {
    fn from(value: BranchName) -> Self {
        Self(value.0)
    }
}
impl Display for GitRef {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "{}", self.0)
    }
}

pub enum ResetForce {
    #[allow(dead_code)]
    Normal,
    Force(GitRef),
}
pub fn reset(
    branch: &BranchName,
    gitref: impl Into<GitRef>,
    reset_force: ResetForce,
    repo_details: &config::RepoDetails,
) -> Result<(), std::io::Error> {
    let gitref: GitRef = gitref.into();
    let user = &repo_details.forge.user;
    let token = &repo_details.forge.token;
    let hostname = &repo_details.forge.hostname;
    let path = &repo_details.repo;
    let origin = format!("https://{user}:{token}@{hostname}/{path}.git");
    let force = match reset_force {
        ResetForce::Normal => "".to_string(),
        ResetForce::Force(old_ref) => format!("--force-with-lease={branch}:{old_ref}"),
    };
    let command = format!("/usr/bin/git push {origin} {gitref}:{branch} {force}");
    info!("Running command: {}", command);
    match gix::command::prepare(command)
        .with_shell_allow_argument_splitting()
        .spawn()
    {
        Ok(mut child) => match child.wait() {
            Ok(_) => Ok(()),
            Err(err) => {
                warn!(?err, "Advance Next Failed (wait)");
                Err(err)
            }
        },
        Err(err) => {
            warn!(?err, "Advance Next Failed (spawn)");
            Err(err)
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[actix_rt::test]
    async fn test_find_next_commit_on_dev() {
        let next = forge::Commit::new("current-next");
        let dev_commit_history = vec![
            forge::Commit::new("dev"),
            forge::Commit::new("dev-next"),
            forge::Commit::new("current-next"),
            forge::Commit::new("current-main"),
        ];
        let next_commit = find_next_commit_on_dev(next, dev_commit_history);
        assert_eq!(next_commit, Some(forge::Commit::new("dev-next")));
    }
}