//! Non-destructive local Git config edits. No plugin-owned persistent format.
use crate::Result;
use crate::{repo::error, ssh::clean_url};
use gix::bstr::ByteSlice;

/// Remote identity.
#[derive(serde::Serialize, serde::Deserialize)]
pub struct RemoteParams {
    /// Plain name under /repos (a-z0-9._-, no '..'), or absolute path under /plugins/ or /repos/ (no empty, '.' or '..' segments or trailing slash).
    pub repo: String,
    /// Remote name.
    pub name: String,
}
/// Add or change a remote URL.
#[derive(serde::Serialize, serde::Deserialize)]
pub struct RemoteUrlParams {
    /// Plain name under /repos (a-z0-9._-, no '..'), or absolute path under /plugins/ or /repos/ (no empty, '.' or '..' segments or trailing slash).
    pub repo: String,
    /// Remote name.
    pub name: String,
    /// HTTPS without credentials, ssh:// URL, or [user@]host:path.
    pub url: String,
}
/// Remote settings stored in local .git/config.
#[derive(serde::Serialize, serde::Deserialize)]
pub struct RemoteInfo {
    /// Remote name.
    pub name: String,
    /// Credential-free URL, if configured.
    pub url: Option<String>,
    /// Fetch refspecs in config order.
    pub fetch: Vec<String>,
}
pub fn validate_name(name: &str) -> Result<()> {
    if name.is_empty()
        || name.starts_with('-')
        || name.contains('/')
        || name.contains("..")
        || !name
            .bytes()
            .all(|b| b.is_ascii_alphanumeric() || b"._-".contains(&b))
    {
        return Err(error(
            "remote",
            "expected a remote name using letters, digits, ._-",
        ));
    }
    let _: gix::refs::FullName = format!("refs/remotes/{name}/branch")
        .as_str()
        .try_into()
        .map_err(|e| error("remote name", e))?;
    Ok(())
}
pub fn load(repo: &gix::Repository) -> Result<gix::config::File> {
    let text = std::fs::read_to_string(repo.common_dir().join("config"))
        .map_err(|e| error("remote config", e))?;
    gix::config::File::try_from(text.as_str())
        .map_err(|_| error("remote config", "could not parse .git/config"))
}
pub fn save(repo: &gix::Repository, config: &gix::config::File) -> Result<()> {
    let mut bytes = Vec::new();
    config
        .write_to(&mut bytes)
        .map_err(|e| error("remote config", e))?;
    std::fs::write(repo.common_dir().join("config"), bytes).map_err(|e| error("config write", e))
}
pub fn list(repo: &gix::Repository) -> Result<Vec<RemoteInfo>> {
    let config = load(repo)?;
    let mut names = std::collections::BTreeSet::new();
    for section in config.sections_by_name("remote").into_iter().flatten() {
        if let Some(name) = section.header().subsection_name() {
            names.insert(name.to_str_lossy().into_owned());
        }
    }
    names
        .into_iter()
        .map(|name| {
            let url = config
                .string_by("remote", name.as_str(), "url")
                .map(|s| s.to_str_lossy().into_owned());
            // Do not return legacy embedded credentials from repositories imported outside this plugin.
            let url = url
                .map(|s| {
                    clean_url(&s).map_err(|_| {
                        error(
                            "remote list",
                            "remote URL must be HTTPS without credentials or SSH without password",
                        )
                    })
                })
                .transpose()?;
            let fetch = config
                .strings_by("remote", name.as_str(), "fetch")
                .unwrap_or_default()
                .into_iter()
                .map(|s| s.to_str_lossy().into_owned())
                .collect();
            Ok(RemoteInfo { name, url, fetch })
        })
        .collect()
}
pub fn set(repo: &gix::Repository, name: &str, url: &str, add: bool) -> Result<RemoteInfo> {
    validate_name(name)?;
    let url = clean_url(url)
        .map_err(|e| error("remote URL", e))?
        .to_string();
    let mut config = load(repo)?;
    let exists = config.section("remote", name).is_ok();
    if add == exists {
        return Err(error(
            "remote",
            if add {
                "remote already exists"
            } else {
                "remote does not exist"
            },
        ));
    }
    // Change URL values in place, preserving config order and other keys/comments.
    if !add {
        let ids: Vec<_> = config
            .sections_and_ids_by_name("remote")
            .into_iter()
            .flatten()
            .filter(|(s, _)| {
                s.header()
                    .subsection_name()
                    .is_some_and(|s| s == name.as_bytes())
            })
            .map(|(_, id)| id)
            .collect();
        for id in ids {
            if let Some(mut section) = config.section_mut_by_id(id) {
                section
                    .set("url", url.as_str())
                    .map_err(|e| error("remote config", e))?;
            }
        }
    }
    let mut section = config
        .section_mut_or_create_new("remote", name)
        .map_err(|e| error("remote config", e))?;
    if add {
        section
            .push("url", Some(url.as_str().into()))
            .map_err(|e| error("remote config", e))?;
        section
            .push(
                "fetch",
                Some(
                    format!("+refs/heads/*:refs/remotes/{name}/*")
                        .as_str()
                        .into(),
                ),
            )
            .map_err(|e| error("remote config", e))?;
    }
    save(repo, &config)?;
    list(repo)?
        .into_iter()
        .find(|r| r.name == name)
        .ok_or_else(|| error("remote", "remote missing after config edit"))
}
pub fn remove(repo: &gix::Repository, name: &str) -> Result<()> {
    validate_name(name)?;
    let mut config = load(repo)?;
    if config.remove_section("remote", name).is_none() {
        return Err(error("remote", "remote does not exist"));
    }
    while config.remove_section("remote", name).is_some() {}
    save(repo, &config)
}
/// Configure the newly cloned branch's upstream with the same non-destructive editor.
pub fn upstream(repo: &gix::Repository, branch: &str) -> Result<()> {
    let mut config = load(repo)?;
    let mut section = config
        .section_mut_or_create_new("branch", branch)
        .map_err(|e| error("branch config", e))?;
    section
        .push("remote", Some("origin".into()))
        .map_err(|e| error("branch config", e))?;
    section
        .push(
            "merge",
            Some(format!("refs/heads/{branch}").as_str().into()),
        )
        .map_err(|e| error("branch config", e))?;
    save(repo, &config)
}