memstead-cli 0.2.0

//! HTTP client for the Memstead registry (memstead.io).
//!
//! Thin wrapper around `reqwest::blocking` that knows the two routes
//! the CLI consumes (`POST /api/publish`, `GET /api/mem/...`) plus
//! the typed error envelope (`ApiError`) the registry emits.

use std::io::Read;
use std::path::Path;
use std::time::Duration;

use anyhow::{Context, Result};
use serde::{Deserialize, Serialize};

/// Default registry when no `--registry` / `MEMSTEAD_REGISTRY` is set.
///
/// `memstead.io` is the canonical registry. The legacy domain is retired —
/// it no longer serves the public registry and is not a fallback.
pub const DEFAULT_REGISTRY: &str = "https://memstead.io";

/// The decoded wire-level error shape the registry returns on any
/// non-2xx. `variant` is present only for `validation_failed`
/// responses; other error kinds leave it `None`.
#[derive(Debug, Clone, Deserialize, Serialize)]
pub struct ApiErrorBody {
    pub error: String,
    #[serde(default)]
    pub variant: Option<String>,
    #[serde(default)]
    pub detail: Option<String>,
    #[serde(default)]
    pub path: Option<String>,
    #[serde(default)]
    pub retry_after_seconds: Option<i64>,
}

/// Outcome of a successful `/api/publish` POST.
#[derive(Debug, Clone, Deserialize)]
pub struct PublishResponse {
    #[allow(dead_code)]
    pub ok: bool,
    pub scope: String,
    pub name: String,
    pub version: String,
    /// The version that is `current` for the handle after this publish
    /// (highest published, semver). Differs from `version` when an older
    /// version was published while a higher one exists. Absent on older
    /// servers that predate the field.
    #[serde(default)]
    pub current: Option<String>,
    /// Path-only — typically `/v/<scope>/<name>`. Caller composes the
    /// full URL against the registry base.
    pub url: String,
}

/// Resolve the registry base URL in priority order: CLI flag →
/// `MEMSTEAD_REGISTRY` env → `DEFAULT_REGISTRY`. Trailing slashes are
/// stripped so callers can unconditionally append route segments.
pub fn registry_base(explicit: Option<&str>) -> String {
    let raw = explicit
        .map(str::to_string)
        .or_else(|| std::env::var("MEMSTEAD_REGISTRY").ok())
        .unwrap_or_else(|| DEFAULT_REGISTRY.to_string());
    raw.trim_end_matches('/').to_string()
}

/// Extract the hostname for credentials keying. Falls back to the
/// full URL on parse failure so nothing silently collides.
pub fn registry_host(base: &str) -> String {
    base.split_once("://")
        .map_or(base, |(_, rest)| rest)
        .split('/')
        .next()
        .unwrap_or(base)
        .to_ascii_lowercase()
}

/// Shared HTTP client. 30 s timeout is comfortable for the 2 MB cap
/// times a slow upstream — GitHub API is also cheap to tolerate.
pub fn build_http() -> Result<reqwest::blocking::Client> {
    reqwest::blocking::Client::builder()
        .timeout(Duration::from_secs(30))
        .user_agent(concat!("memstead/", env!("CARGO_PKG_VERSION")))
        .build()
        .context("building HTTP client")
}

/// The publisher-terms version the CLI accepts on publish. Running
/// `memstead publish` is a deliberate act, so the CLI accepts the current
/// terms on the publisher's behalf by sending this version. Must track the
/// registry's `CURRENT_TERMS_VERSION`; a mismatch surfaces as a
/// `terms_not_accepted` refusal naming the version, telling the user to update.
pub const ACCEPTED_TERMS_VERSION: &str = "1.0";

/// A per-publish domain-authority signature, presented in request headers for a
/// `<domain>:<handle>` publish. The CLI builds this from the domain's stored key
/// (see `crate::auth::domain_key`); the registry verifies it against the hosted
/// proof manifest.
#[derive(Debug, Clone)]
pub struct DomainSignature {
    /// `ed25519:<base64>` public key the signature was made with.
    pub key: String,
    /// `ed25519:<base64>` signature over the canonical publish payload.
    pub signature: String,
    /// Publish timestamp, unix seconds.
    pub timestamp: i64,
}

/// POST a sealed `.mem` archive to `/api/publish`. Returns the parsed
/// success body or a typed `ApiErrorBody` on any non-2xx.
///
/// Authorisation is one of two channels: a GitHub `token` (the default path),
/// or a `domain_sig` for a `<domain>:<handle>` publish, which needs no GitHub
/// account. Exactly one should be supplied for a given publish.
pub fn publish(
    client: &reqwest::blocking::Client,
    base: &str,
    archive: &Path,
    token: Option<&str>,
    scope_override: Option<&str>,
    domain_sig: Option<&DomainSignature>,
) -> Result<PublishResponse, PublishError> {
    use memstead_base::domain_authority_wire::{HEADER_KEY, HEADER_SIGNATURE, HEADER_TIMESTAMP};

    let url = format!("{base}/api/publish");
    let mut file = std::fs::File::open(archive).map_err(PublishError::Io)?;
    let mut bytes = Vec::new();
    file.read_to_end(&mut bytes).map_err(PublishError::Io)?;

    let mut req = client
        .post(&url)
        .header("content-type", "application/octet-stream")
        .header("x-memstead-accept-terms", ACCEPTED_TERMS_VERSION)
        .body(bytes);
    if let Some(t) = token {
        req = req.bearer_auth(t);
    }
    if let Some(s) = scope_override {
        req = req.header("x-memstead-scope", s);
    }
    if let Some(ds) = domain_sig {
        req = req
            .header(HEADER_KEY, &ds.key)
            .header(HEADER_SIGNATURE, &ds.signature)
            .header(HEADER_TIMESTAMP, ds.timestamp.to_string());
    }

    let resp = req.send().map_err(PublishError::Network)?;
    let status = resp.status();
    let body_bytes = resp.bytes().map_err(PublishError::Network)?;

    if status.is_success() {
        return serde_json::from_slice::<PublishResponse>(&body_bytes)
            .map_err(|e| PublishError::Malformed(e.to_string()));
    }

    // Non-2xx: try the typed envelope, fall back to raw text.
    match serde_json::from_slice::<ApiErrorBody>(&body_bytes) {
        Ok(envelope) => Err(PublishError::Api { status, envelope }),
        Err(_) => {
            let text = String::from_utf8_lossy(&body_bytes).into_owned();
            Err(PublishError::Raw { status, text })
        }
    }
}

/// Outcome of a successful `DELETE /api/mem/<scope>/<name>`.
#[derive(Debug, Clone, Deserialize)]
pub struct UnpublishResponse {
    #[allow(dead_code)]
    pub ok: bool,
    pub scope: String,
    pub name: String,
}

/// DELETE a mem from the registry. Same auth + error envelope as
/// publish, so reuse `PublishError` for the failure shape.
pub fn unpublish(
    client: &reqwest::blocking::Client,
    base: &str,
    scope: &str,
    name: &str,
    token: &str,
) -> Result<UnpublishResponse, PublishError> {
    let url = format!(
        "{base}/api/mem/{scope}/{name}",
        scope = url_segment(scope),
        name = url_segment(name),
    );
    let resp = client
        .delete(&url)
        .bearer_auth(token)
        .send()
        .map_err(PublishError::Network)?;
    let status = resp.status();
    let body_bytes = resp.bytes().map_err(PublishError::Network)?;

    if status.is_success() {
        return serde_json::from_slice::<UnpublishResponse>(&body_bytes)
            .map_err(|e| PublishError::Malformed(e.to_string()));
    }

    match serde_json::from_slice::<ApiErrorBody>(&body_bytes) {
        Ok(envelope) => Err(PublishError::Api { status, envelope }),
        Err(_) => {
            let text = String::from_utf8_lossy(&body_bytes).into_owned();
            Err(PublishError::Raw { status, text })
        }
    }
}

/// Admin-only takedown of a published mem: same `DELETE` route as
/// `unpublish`, but with the `x-memstead-takedown` header carrying the
/// statement-of-reasons notice reference. The server selects the
/// takedown path (deny-list the bytes, tombstone, burn the name)
/// instead of an ordinary hard-delete, and refuses non-admins with 403.
pub fn admin_takedown(
    client: &reqwest::blocking::Client,
    base: &str,
    scope: &str,
    name: &str,
    notice: &str,
    token: &str,
) -> Result<UnpublishResponse, PublishError> {
    let url = format!(
        "{base}/api/mem/{scope}/{name}",
        scope = url_segment(scope),
        name = url_segment(name),
    );
    let resp = client
        .delete(&url)
        .bearer_auth(token)
        .header("x-memstead-takedown", notice)
        .send()
        .map_err(PublishError::Network)?;
    let status = resp.status();
    let body_bytes = resp.bytes().map_err(PublishError::Network)?;

    if status.is_success() {
        return serde_json::from_slice::<UnpublishResponse>(&body_bytes)
            .map_err(|e| PublishError::Malformed(e.to_string()));
    }
    match serde_json::from_slice::<ApiErrorBody>(&body_bytes) {
        Ok(envelope) => Err(PublishError::Api { status, envelope }),
        Err(_) => {
            let text = String::from_utf8_lossy(&body_bytes).into_owned();
            Err(PublishError::Raw { status, text })
        }
    }
}

/// Outcome of a successful `POST /api/admin/denylist`.
#[derive(Debug, Clone, Deserialize)]
pub struct DenylistResponse {
    #[allow(dead_code)]
    pub ok: bool,
    pub content_sha256: String,
}

/// Admin-only: add a canonical-bytes SHA-256 to the content deny-list so
/// those exact bytes can never be published. Refuses non-admins with 403.
pub fn admin_denylist(
    client: &reqwest::blocking::Client,
    base: &str,
    content_sha256: &str,
    reason: Option<&str>,
    token: &str,
) -> Result<DenylistResponse, PublishError> {
    let url = format!("{base}/api/admin/denylist");
    let resp = client
        .post(&url)
        .bearer_auth(token)
        .json(&serde_json::json!({ "content_sha256": content_sha256, "reason": reason }))
        .send()
        .map_err(PublishError::Network)?;
    let status = resp.status();
    let body_bytes = resp.bytes().map_err(PublishError::Network)?;

    if status.is_success() {
        return serde_json::from_slice::<DenylistResponse>(&body_bytes)
            .map_err(|e| PublishError::Malformed(e.to_string()));
    }
    match serde_json::from_slice::<ApiErrorBody>(&body_bytes) {
        Ok(envelope) => Err(PublishError::Api { status, envelope }),
        Err(_) => {
            let text = String::from_utf8_lossy(&body_bytes).into_owned();
            Err(PublishError::Raw { status, text })
        }
    }
}

/// GET a sealed `.mem` archive from the registry, streaming into
/// `dest_path`. Returns the number of bytes written.
pub fn download_mem(
    client: &reqwest::blocking::Client,
    base: &str,
    scope: &str,
    name: &str,
    dest_path: &Path,
) -> Result<u64, DownloadError> {
    let url = format!(
        "{base}/api/mem/{scope}/{name}.mem",
        scope = url_segment(scope),
        name = url_segment(name),
    );
    let resp = client.get(&url).send().map_err(DownloadError::Network)?;
    let status = resp.status();
    if !status.is_success() {
        return match status.as_u16() {
            404 => Err(DownloadError::NotFound),
            410 => Err(DownloadError::Gone),
            _ => {
                let text = resp.text().unwrap_or_default();
                Err(DownloadError::Http {
                    status,
                    text: text.chars().take(500).collect(),
                })
            }
        };
    }
    let bytes = resp.bytes().map_err(DownloadError::Network)?;
    std::fs::write(dest_path, &bytes).map_err(DownloadError::Io)?;
    Ok(bytes.len() as u64)
}

/// Minimal percent-encoding for a single path segment. Our scope +
/// name are slug-safe by server validation (`^[a-z0-9][a-z0-9-]{0,62}[a-z0-9]$`),
/// so a character set check is sufficient — the server would 400 any
/// non-slug anyway. Kept as a fn for explicitness.
fn url_segment(raw: &str) -> String {
    // Preserve the scope-form characters `:` (scheme/domain separator) and
    // `.` (domain labels) — both valid in a URL path segment — alongside the
    // slug characters; drop anything else as a path-shape defence.
    raw.chars()
        .filter(|c| c.is_ascii_alphanumeric() || matches!(*c, '-' | '_' | ':' | '.'))
        .collect()
}

/// Parse a registry ref `<scope>/<name>` in one of the three scope forms
/// (`github:<handle>/<name>`, `<domain>:<handle>/<name>`, or a bare
/// `<handle>/<name>`). The legacy `@scope/name` syntax is rejected by the
/// caller before this is reached. Returns `None` for anything that is not a
/// valid registry ref (e.g. a local file path), so `install` can fall back to
/// a local install.
pub fn parse_ref(raw: &str) -> Option<(String, String)> {
    let (scope, name) = raw.split_once('/')?;
    // The name is a bare slug — no extension, no further path segments.
    if name.is_empty() || name.contains('.') || name.contains('/') || name.contains('\\') {
        return None;
    }
    if !is_valid_scope_form(scope) {
        return None;
    }
    Some((scope.to_string(), name.to_string()))
}

fn is_valid_handle(h: &str) -> bool {
    !h.is_empty()
        && h.len() <= 39
        && !h.starts_with('-')
        && !h.ends_with('-')
        && h.bytes().all(|b| b.is_ascii_alphanumeric() || b == b'-')
}

/// `github:<handle>`, `<domain>:<handle>` (domain has a `.`), or bare `<handle>`.
fn is_valid_scope_form(scope: &str) -> bool {
    match scope.split_once(':') {
        Some((prefix, handle)) => {
            is_valid_handle(handle)
                && (prefix == "github"
                    || (prefix.contains('.')
                        && prefix.split('.').all(|label| {
                            !label.is_empty()
                                && label
                                    .bytes()
                                    .all(|b| b.is_ascii_alphanumeric() || b == b'-')
                        })))
        }
        None => is_valid_handle(scope),
    }
}

#[derive(Debug, thiserror::Error)]
pub enum PublishError {
    #[error("io: {0}")]
    Io(#[from] std::io::Error),
    #[error("network: {0}")]
    Network(reqwest::Error),
    #[error("registry returned {status}: {envelope:?}")]
    Api {
        status: reqwest::StatusCode,
        envelope: ApiErrorBody,
    },
    #[error("registry returned {status}: {text}")]
    Raw {
        status: reqwest::StatusCode,
        text: String,
    },
    #[error("malformed success response: {0}")]
    Malformed(String),
}

#[derive(Debug, thiserror::Error)]
pub enum DownloadError {
    #[error("io: {0}")]
    Io(#[from] std::io::Error),
    #[error("network: {0}")]
    Network(reqwest::Error),
    #[error("not found")]
    NotFound,
    #[error("content taken down")]
    Gone,
    #[error("registry returned {status}: {text}")]
    Http {
        status: reqwest::StatusCode,
        text: String,
    },
}