pub trait GitlabEventExt {
    fn project(&self) -> &Project;
    fn r#ref(&self) -> &str;
    fn user(&self) -> &str;
    fn url(&self) -> String;
    fn title(&self) -> String;
}

#[derive(Debug, Deserialize)]
pub struct Project {
    pub id: u64,
    pub name: String,
    pub description: String,
    pub web_url: String,
    pub avatar_url: Option<String>,
    pub git_ssh_url: String,
    pub git_http_url: String,
    pub namespace: String,
    pub visibility_level: u32,
    pub path_with_namespace: String,
    pub default_branch: String,
    pub homepage: String,
    pub url: String,
    pub ssh_url: String,
    pub http_url: String,
}

#[derive(Debug, Deserialize)]
pub struct Repository {
    pub name: String,
    pub url: String,
    pub description: String,
    pub homepage: String,
    pub git_http_url: String,
    pub git_ssh_url: String,
    pub visibility_level: u32,
}

#[derive(Debug, Deserialize)]
pub struct Commit {
    pub id: String,
    pub title: String,
    pub url: String,
}

#[derive(Debug, Deserialize)]
#[serde(tag = "object_kind")]
pub enum GitlabEvent {
    #[serde(rename = "push")]
    Push {
        event_name: String,
        before: String,
        after: String,
        r#ref: String,
        ref_protected: bool,
        checkout_sha: String,
        user_id: u64,
        user_name: String,
        user_username: String,
        user_email: String,
        user_avatar: Option<String>,
        project_id: u64,
        project: Project,
        repository: Repository,
        commits: Vec<Commit>,
        total_commits_count: u64,
    },
    #[serde(rename = "tag_push")]
    TagPush {
        event_name: String,
        before: String,
        after: String,
        r#ref: String,
        ref_protected: bool,
        checkout_sha: String,
        user_id: u64,
        user_name: String,
        user_avatar: Option<String>,
        project_id: u64,
        project: Project,
        repository: Repository,
        commits: Vec<Commit>,
        total_commits_count: u64,
    },
}

impl GitlabEventExt for GitlabEvent {
    fn project(&self) -> &Project {
        match self {
            GitlabEvent::Push { project, .. } => &project,
            GitlabEvent::TagPush { project, .. } => &project,
        }
    }

    fn r#ref(&self) -> &str {
        match self {
            GitlabEvent::Push { r#ref, .. } => &r#ref,
            GitlabEvent::TagPush { r#ref, .. } => &r#ref,
        }
    }

    fn user(&self) -> &str {
        match self {
            GitlabEvent::Push { user_name, .. } => &user_name,
            GitlabEvent::TagPush { user_name, .. } => &user_name,
        }
    }

    fn url(&self) -> String {
        let url = match self {
            GitlabEvent::Push { after, project, .. } => format!("{}/-/commits/{}", project.web_url, after),
            GitlabEvent::TagPush {
                r#ref,
                checkout_sha,
                project,
                ..
            } => {
                let refname = r#ref.split('/').into_iter().last().unwrap_or(checkout_sha);
                format!("{}/-/tags/{}", project.web_url, refname)
            }
        };

        url.replace("http://", "https://").to_string()
    }

    fn title(&self) -> String {
        fn find_commit<'a>(commits: &'a Vec<Commit>, sha: &str) -> Option<&'a Commit> {
            commits.iter().find(|commit| commit.id == sha)
        }

        match self {
            GitlabEvent::Push { after, commits, .. } => find_commit(commits, &after)
                .map(|commit| commit.title.clone())
                .unwrap_or_else(|| "New commit(s) pushed".to_string()),
            GitlabEvent::TagPush {
                checkout_sha, commits, ..
            } => find_commit(commits, &checkout_sha)
                .map(|commit| commit.title.clone())
                .unwrap_or_else(|| "New tag pushed".to_string()),
        }
    }
}

#[cfg(test)]
mod test {
    use super::*;
    use std::{fs::File, io::BufReader};

    fn load_test_data(name: &str) -> anyhow::Result<GitlabEvent> {
        let f = File::open(&format!("{}/test-data/{}.json", env!("CARGO_MANIFEST_DIR"), name))?;
        let r = BufReader::new(f);
        let event: GitlabEvent = serde_json::from_reader(r)?;
        Ok(event)
    }

    #[test]
    pub fn parse_push_event() -> anyhow::Result<()> {
        let event = load_test_data("push-event")?;

        match event {
            GitlabEvent::Push {
                event_name,
                before,
                after,
                r#ref,
                checkout_sha,
                user_username,
                project,
                repository,
                total_commits_count,
                ..
            } => {
                assert_eq!(event_name, "push");
                assert_eq!(before, "95790bf891e76fee5e1747ab589903a6a1f80f22");
                assert_eq!(after, "da1560886d4f094c3e6c9ef40349f7d38b5d27d7");
                assert_eq!(r#ref, "refs/heads/master");
                assert_eq!(checkout_sha, "da1560886d4f094c3e6c9ef40349f7d38b5d27d7");
                assert_eq!(user_username, "jsmith");
                assert_eq!(project.name, "Diaspora");
                assert_eq!(project.namespace, "Mike");
                assert_eq!(repository.name, "Diaspora");
                assert_eq!(repository.url, "git@example.com:mike/diaspora.git");
                assert_eq!(total_commits_count, 4);
            }
            _ => panic!("not a push event"),
        };

        Ok(())
    }

    #[test]
    pub fn parse_tag_push_event() -> anyhow::Result<()> {
        let event = load_test_data("tag-push-event")?;

        match event {
            GitlabEvent::TagPush {
                event_name,
                before,
                after,
                r#ref,
                checkout_sha,
                user_name,
                project,
                repository,
                total_commits_count,
                ..
            } => {
                assert_eq!(event_name, "tag_push");
                assert_eq!(before, "0000000000000000000000000000000000000000");
                assert_eq!(after, "82b3d5ae55f7080f1e6022629cdb57bfae7cccc7");
                assert_eq!(r#ref, "refs/tags/v1.0.0");
                assert_eq!(checkout_sha, "82b3d5ae55f7080f1e6022629cdb57bfae7cccc7");
                assert_eq!(user_name, "John Smith");
                assert_eq!(project.name, "Example");
                assert_eq!(project.namespace, "Jsmith");
                assert_eq!(repository.name, "Example");
                assert_eq!(total_commits_count, 0);
            }
            _ => panic!("not a tag push event"),
        };

        Ok(())
    }
}