//! Secrets for OxygenFlow jobs (hub spec §13.2, oxygenhub#107): named
//! values kept per site, organisation and repository, sealed at rest
//! under `keys/secrets.key`. A job gets only the secrets its pipeline
//! declares with `secret "name" { mount-path … }`, as files Flow mounts
//! (OxygenFlow spec §9), never in the environment; the hub masks each
//! value in the job's log as it arrives. Inner levels override outer by
//! name, as variables do.

use crate::db::{now_ms, Pool};
use crate::levels::{self, Scope};
use crate::Shared;
use sqlx::FromRow;

/// How many a level may hold.
pub const MAX_PER_LEVEL: usize = 100;
/// The longest value, in bytes.
pub const MAX_VALUE: usize = 64 * 1024;
/// Values shorter than this are not masked in logs: too many false hits.
const MIN_MASKED: usize = 4;

#[derive(Clone, Debug, FromRow)]
pub struct Secret {
    pub scope: String,
    pub scope_id: i64,
    pub name: String,
    /// Sealed; `App.secret_key` opens it.
    pub value: Vec<u8>,
    pub updated_ms: i64,
}

/// A secret's name, as a pipeline names it: 1 to 64 of `A-Z a-z 0-9 . _ -`.
pub fn name_ok(name: &str) -> bool {
    !name.is_empty() && name.len() <= 64 && name.bytes().all(|b| b.is_ascii_alphanumeric() || b".-_".contains(&b))
}

pub async fn list(pool: &Pool, scope: Scope) -> sqlx::Result<Vec<Secret>> {
    sqlx::query_as("SELECT * FROM flow_secrets WHERE scope = ? AND scope_id = ? ORDER BY name")
        .bind(scope.kind())
        .bind(scope.id())
        .fetch_all(pool)
        .await
}

/// Set a secret at a level, new or changed; `sealed` is the value sealed.
pub async fn set(pool: &Pool, scope: Scope, name: &str, sealed: &[u8]) -> sqlx::Result<()> {
    sqlx::query(
        "INSERT INTO flow_secrets (scope, scope_id, name, value, updated_ms) VALUES (?, ?, ?, ?, ?) \
         ON CONFLICT (scope, scope_id, name) DO UPDATE SET value = excluded.value, updated_ms = excluded.updated_ms",
    )
    .bind(scope.kind())
    .bind(scope.id())
    .bind(name)
    .bind(sealed)
    .bind(now_ms())
    .execute(pool)
    .await?;
    Ok(())
}

/// Remove a secret from a level; false when it was not there.
pub async fn delete(pool: &Pool, scope: Scope, name: &str) -> sqlx::Result<bool> {
    let r = sqlx::query("DELETE FROM flow_secrets WHERE scope = ? AND scope_id = ? AND name = ?")
        .bind(scope.kind())
        .bind(scope.id())
        .bind(name)
        .execute(pool)
        .await?;
    Ok(r.rows_affected() == 1)
}

/// Forget a level's secrets, when the organisation or repository goes.
pub async fn delete_scope(pool: &Pool, scope: Scope) -> sqlx::Result<()> {
    sqlx::query("DELETE FROM flow_secrets WHERE scope = ? AND scope_id = ?").bind(scope.kind()).bind(scope.id()).execute(pool).await?;
    Ok(())
}

/// A secret as a level sees it: where from, and whether an inner level
/// sets the same name. The value stays sealed.
#[derive(Clone, Debug)]
pub struct Seen {
    pub secret: Secret,
    /// `the site`, `the acme organisation`, or empty for the level's own.
    pub from: String,
    pub overridden: bool,
}

/// Every secret a level sees, outermost first.
pub async fn seen(pool: &Pool, scope: Scope, owner: &str) -> sqlx::Result<Vec<Seen>> {
    let mut lvls = levels::above(pool, scope, owner).await?;
    lvls.push((scope, String::new()));
    let mut out: Vec<Seen> = vec![];
    for (level, from) in lvls {
        for s in list(pool, level).await? {
            for o in out.iter_mut().filter(|o| o.secret.name == s.name) {
                o.overridden = true;
            }
            out.push(Seen { secret: s, from: from.clone(), overridden: false });
        }
    }
    Ok(out)
}

/// The values of the named secrets as a repository's jobs get them:
/// `(name, value)` for each that is set and opens; names not set are
/// left out, as are values sealed under another key.
pub async fn for_job(app: &Shared, repo: &crate::db::repos::RepoRow, names: &[String]) -> sqlx::Result<Vec<(String, String)>> {
    let all = seen(&app.db, Scope::Repo(repo.id), &repo.owner).await?;
    let mut out = vec![];
    for name in names {
        if let Some(s) = all.iter().find(|s| !s.overridden && s.secret.name == *name) {
            if let Some(value) = app.secret_key.open(&s.secret.value) {
                out.push((name.clone(), value));
            }
        }
    }
    Ok(out)
}

/// `text` with every secret value (and its standard base64) replaced by
/// `***`, for a job's log.
pub fn mask(text: &str, values: &[String]) -> String {
    let mut out = text.to_string();
    for v in values {
        if v.len() < MIN_MASKED {
            continue;
        }
        out = out.replace(v.as_str(), "***");
        let b64 = base64_standard(v.as_bytes());
        if b64.len() >= MIN_MASKED {
            out = out.replace(&b64, "***");
        }
    }
    out
}

fn base64_standard(bytes: &[u8]) -> String {
    const T: &[u8; 64] = b"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
    let mut out = String::with_capacity(bytes.len().div_ceil(3) * 4);
    for chunk in bytes.chunks(3) {
        let n = chunk.iter().fold(0u32, |acc, b| (acc << 8) | *b as u32) << (8 * (3 - chunk.len()));
        for i in 0..4 {
            if i <= chunk.len() {
                out.push(T[((n >> (18 - 6 * i)) & 63) as usize] as char);
            } else {
                out.push('=');
            }
        }
    }
    out
}

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

    #[test]
    fn values_and_their_base64_are_masked_in_logs() {
        assert_eq!(base64_standard(b"hunter22"), "aHVudGVyMjI=");
        let line = "token=hunter22 b64=aHVudGVyMjI= short=ab done";
        assert_eq!(mask(line, &["hunter22".into(), "ab".into()]), "token=*** b64=*** short=ab done");
        assert!(name_ok("deploy-token") && name_ok("aws.key_1") && !name_ok("") && !name_ok("a b") && !name_ok(&"x".repeat(65)));
    }
}