git-stk 0.5.0

use std::{fmt, process::Command};

use anyhow::{Context, Result, anyhow, bail};

use crate::git;
use crate::settings;

mod github;
mod gitlab;
mod json;

use github::GitHubProvider;
use gitlab::GitLabProvider;

#[derive(Debug, Clone, Copy, Eq, PartialEq)]
pub enum ProviderKind {
    GitHub,
    GitLab,
}

impl ProviderKind {
    fn parse(value: &str) -> Option<Self> {
        match value.to_ascii_lowercase().as_str() {
            "github" | "gh" => Some(Self::GitHub),
            "gitlab" | "glab" => Some(Self::GitLab),
            _ => None,
        }
    }
}

impl fmt::Display for ProviderKind {
    fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            Self::GitHub => write!(formatter, "github"),
            Self::GitLab => write!(formatter, "gitlab"),
        }
    }
}

#[derive(Debug, Eq, PartialEq)]
pub struct DetectedProvider {
    pub kind: ProviderKind,
    pub source: ProviderSource,
}

#[derive(Debug, Eq, PartialEq)]
pub enum ProviderSource {
    Config,
    Remote { remote: String, url: String },
}

impl fmt::Display for ProviderSource {
    fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            Self::Config => write!(formatter, "config"),
            Self::Remote { remote, url } => write!(formatter, "remote {remote} ({url})"),
        }
    }
}

#[derive(Debug, Eq, PartialEq)]
pub enum ReviewState {
    Open,
    Merged,
    Closed,
    Unknown(String),
}

#[derive(Debug, Eq, PartialEq)]
pub struct ReviewRequest {
    pub id: String,
    pub branch: String,
    pub base: String,
    pub state: ReviewState,
    pub url: String,
    pub title: String,
}

pub trait ReviewProvider {
    fn review_for_branch(&self, branch: &str) -> Result<Option<ReviewRequest>>;

    fn create_review(&self, branch: &str, base: &str) -> Result<String>;

    fn update_review_base(&self, review: &ReviewRequest, base: &str) -> Result<String>;

    fn review_body(&self, review: &ReviewRequest) -> Result<String>;

    fn update_review_body(&self, review: &ReviewRequest, body: &str) -> Result<String>;

    /// Merge the review with the given strategy: squash, rebase, or merge.
    fn merge_review(&self, review: &ReviewRequest, strategy: &str) -> Result<String>;
}

pub fn detect_provider() -> Result<DetectedProvider> {
    if let Some(value) = git::config_get(settings::PROVIDER_KEY)? {
        let Some(kind) = ProviderKind::parse(&value) else {
            bail!("unsupported stk.provider value {value:?}; expected github or gitlab");
        };

        return Ok(DetectedProvider {
            kind,
            source: ProviderSource::Config,
        });
    }

    let remote = settings::remote()?;
    let Some(url) = git::remote_url(&remote)? else {
        bail!("could not detect provider: remote {remote:?} does not exist");
    };

    let Some(kind) = detect_provider_from_url(&url) else {
        bail!("could not detect provider from remote {remote} ({url})");
    };

    Ok(DetectedProvider {
        kind,
        source: ProviderSource::Remote { remote, url },
    })
}

fn detect_provider_from_url(url: &str) -> Option<ProviderKind> {
    let normalized = url.to_ascii_lowercase();

    if normalized.contains("github.com:") || normalized.contains("github.com/") {
        Some(ProviderKind::GitHub)
    } else if normalized.contains("gitlab.com:") || normalized.contains("gitlab.com/") {
        Some(ProviderKind::GitLab)
    } else {
        None
    }
}

pub(crate) fn review_provider(kind: ProviderKind) -> Box<dyn ReviewProvider> {
    match kind {
        ProviderKind::GitHub => Box::new(GitHubProvider),
        ProviderKind::GitLab => Box::new(GitLabProvider),
    }
}

fn command_output(program: &str, args: &[&str]) -> Result<String> {
    let output = Command::new(program)
        .args(args)
        .output()
        .with_context(|| format!("failed to run {program}"))?;

    if output.status.success() {
        Ok(String::from_utf8_lossy(&output.stdout).trim().to_owned())
    } else {
        let stderr = String::from_utf8_lossy(&output.stderr).trim().to_owned();
        if stderr.is_empty() {
            Err(anyhow!("{program} exited with status {}", output.status))
        } else {
            Err(anyhow!("{program} failed: {stderr}"))
        }
    }
}

impl fmt::Display for ReviewState {
    fn fmt(&self, formatter: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            Self::Open => write!(formatter, "open"),
            Self::Merged => write!(formatter, "merged"),
            Self::Closed => write!(formatter, "closed"),
            Self::Unknown(state) => write!(formatter, "{state}"),
        }
    }
}

impl ReviewRequest {
    pub(crate) fn id_value(&self) -> &str {
        self.id
            .strip_prefix('#')
            .or_else(|| self.id.strip_prefix('!'))
            .unwrap_or(&self.id)
    }
}