teams-cli 0.2.2

use std::collections::HashMap;
use std::time::{Duration, SystemTime, UNIX_EPOCH};

use base64::Engine;
use rand::RngCore;
use serde::{Deserialize, Serialize};
use sha2::{Digest, Sha256};
use tokio::io::{AsyncReadExt, AsyncWriteExt};
use tokio::net::TcpListener;

use crate::config::{CredentialStore, Profile};
use crate::error::AppError;
use crate::output::Output;

pub const BASE_SCOPES: &str = "openid profile offline_access User.Read User.ReadBasic.All Team.ReadBasic.All Channel.ReadBasic.All Chat.Read Chat.Create ChatMessage.Send ChannelMessage.Send";
pub const CHANNEL_HISTORY_SCOPE: &str = "ChannelMessage.Read.All";
pub const CHANNEL_HISTORY_SCOPES: &str = "openid profile offline_access User.Read User.ReadBasic.All Team.ReadBasic.All Channel.ReadBasic.All Chat.Read Chat.Create ChatMessage.Send ChannelMessage.Send ChannelMessage.Read.All";
const SERVICE: &str = "teams-cli";

mod pass;
mod process;

#[cfg(any(target_os = "linux", test))]
mod wsl;

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct TokenBundle {
    pub access_token: String,
    pub refresh_token: Option<String>,
    pub expires_at: u64,
    pub scope: Option<String>,
}

#[derive(Debug, Deserialize)]
struct TokenResponse {
    access_token: String,
    refresh_token: Option<String>,
    expires_in: u64,
    scope: Option<String>,
}

#[derive(Debug, Deserialize)]
struct OAuthError {
    error: String,
    error_description: Option<String>,
}

fn now() -> u64 {
    SystemTime::now()
        .duration_since(UNIX_EPOCH)
        .unwrap_or_default()
        .as_secs()
}

fn entry(profile_name: &str) -> Result<keyring::Entry, AppError> {
    let profile = crate::config::connection_profile(Some(profile_name))?;
    entry_for(profile_name, profile.as_ref())
}

fn entry_for(profile_name: &str, profile: Option<&Profile>) -> Result<keyring::Entry, AppError> {
    if let Some(profile) = profile
        && profile.credential_store == CredentialStore::Pass
    {
        let directory = profile.pass_store_dir.as_deref().ok_or_else(|| AppError::InvalidInput(
            "This pass profile has no saved pass_store_dir; restore its original directory in the profile configuration. No other credential store was used".into(),
        ))?;
        return pass::entry(profile_name, directory);
    }
    #[cfg(target_os = "linux")]
    if wsl::is_wsl() {
        return Ok(wsl::entry(profile_name));
    }
    keyring::Entry::new(SERVICE, profile_name)
        .map_err(|e| AppError::Unexpected(format!("credential store is unavailable: {e}")))
}

/// Inspect the selected store without treating a helper/decryption failure as logout.
pub fn credential_present(profile_name: &str) -> Result<bool, AppError> {
    if std::env::var("TEAMS_ACCESS_TOKEN").is_ok() {
        return Ok(true);
    }
    match entry(profile_name)?.get_password() {
        Ok(_) => Ok(true),
        Err(keyring::Error::NoEntry) => Ok(false),
        Err(error) => Err(AppError::Unexpected(format!(
            "Could not read the saved credential: {error}"
        ))),
    }
}

pub fn has_token(profile_name: &str) -> bool {
    credential_present(profile_name).unwrap_or(false)
}

pub fn available_pass_directory() -> Option<std::path::PathBuf> {
    pass::available_directory()
}

pub fn prepare_pass_directory(
    directory: Option<&std::path::Path>,
) -> Result<std::path::PathBuf, AppError> {
    pass::prepare(directory)
}

pub fn native_store_label() -> &'static str {
    #[cfg(target_os = "linux")]
    if wsl::is_wsl() {
        return "Windows DPAPI";
    }
    if cfg!(target_os = "macos") {
        "macOS Keychain"
    } else if cfg!(windows) {
        "Windows Credential Manager"
    } else {
        "Linux Secret Service"
    }
}

/// Probe only the native store when offering a new-profile storage choice.
pub fn native_store_error(profile_name: &str) -> Option<String> {
    let result = entry_for(profile_name, None).and_then(|entry| match entry.get_password() {
        Ok(_) | Err(keyring::Error::NoEntry) => Ok(()),
        Err(error) => Err(AppError::Unexpected(error.to_string())),
    });
    result.err().map(|error| error.to_string())
}

/// Check storage before opening Microsoft sign-in. GPG may prompt for an existing entry.
pub fn check_store(profile_name: &str, profile: &Profile) -> Result<(), AppError> {
    match entry_for(profile_name, Some(profile))?.get_password() {
        Err(keyring::Error::NoEntry) if profile.credential_store == CredentialStore::Pass => {
            pass::probe(
                profile
                    .pass_store_dir
                    .as_deref()
                    .expect("validated pass directory"),
            )
        }
        Ok(_) | Err(keyring::Error::NoEntry) => Ok(()),
        Err(error) => Err(AppError::Unexpected(format!(
            "Credential storage is unavailable: {error}. Sign-in was not started"
        ))),
    }
}

pub fn granted_scopes(profile_name: &str) -> Option<Vec<String>> {
    if std::env::var("TEAMS_ACCESS_TOKEN").is_ok() {
        return None;
    }
    load(profile_name).ok().and_then(|token| {
        token.scope.map(|scope| {
            scope
                .split_whitespace()
                .map(str::to_owned)
                .collect::<Vec<_>>()
        })
    })
}

pub fn channel_history_granted(profile_name: &str) -> Option<bool> {
    granted_scopes(profile_name).map(|scopes| {
        scopes
            .iter()
            .any(|scope| scope.eq_ignore_ascii_case(CHANNEL_HISTORY_SCOPE))
    })
}

fn store(profile_name: &str, profile: &Profile, token: &TokenBundle) -> Result<(), AppError> {
    let encoded = serde_json::to_string(token).map_err(|e| AppError::Unexpected(e.to_string()))?;
    entry_for(profile_name, Some(profile))?
        .set_password(&encoded)
        .map_err(|e| {
            AppError::Unexpected(format!(
                "could not save credentials in the selected credential store: {e}"
            ))
        })
}

fn load(profile_name: &str) -> Result<TokenBundle, AppError> {
    let encoded = entry(profile_name)?
        .get_password()
        .map_err(|error| match error {
            keyring::Error::NoEntry => {
                AppError::Auth("not signed in; run `teams auth login`".into())
            }
            error => AppError::Unexpected(format!("Could not read the saved credential: {error}")),
        })?;
    serde_json::from_str(&encoded).map_err(|_| {
        AppError::Auth("stored credential is unreadable; run `teams auth login` again".into())
    })
}

pub fn logout(profile_name: &str) -> Result<(), AppError> {
    match entry(profile_name)?.delete_credential() {
        Ok(()) | Err(keyring::Error::NoEntry) => Ok(()),
        Err(e) if secret_service_is_unavailable(&e) => Ok(()),
        Err(e) => Err(AppError::Unexpected(format!(
            "could not remove stored credentials: {e}"
        ))),
    }
}

#[cfg(target_os = "linux")]
fn secret_service_is_unavailable(error: &keyring::Error) -> bool {
    match error {
        keyring::Error::PlatformFailure(source) => {
            let message = source.to_string();
            message.contains("org.freedesktop.secrets") && message.contains("not provided")
        }
        _ => false,
    }
}

#[cfg(not(target_os = "linux"))]
fn secret_service_is_unavailable(_error: &keyring::Error) -> bool {
    false
}

pub async fn access_token(profile_name: &str, profile: &Profile) -> Result<String, AppError> {
    profile.require_graph()?;
    if let Ok(token) = std::env::var("TEAMS_ACCESS_TOKEN") {
        return Ok(token);
    }
    let mut bundle = load(profile_name)?;
    if bundle.expires_at > now() + 120 {
        return Ok(bundle.access_token);
    }
    let refresh = bundle.refresh_token.as_deref().ok_or_else(|| {
        AppError::Auth(
            "session expired and has no refresh credential; run `teams auth login`".into(),
        )
    })?;
    let response = reqwest::Client::new()
        .post(token_url(profile))
        .form(&[
            ("client_id", profile.client_id.as_str()),
            ("grant_type", "refresh_token"),
            ("refresh_token", refresh),
            ("scope", bundle.scope.as_deref().unwrap_or(BASE_SCOPES)),
        ])
        .send()
        .await
        .map_err(|e| AppError::Unexpected(format!("sign-in service is unreachable: {e}")))?;
    let mut replacement = parse_token_response(response).await?;
    if replacement.refresh_token.is_none() {
        replacement.refresh_token = bundle.refresh_token.clone();
    }
    bundle = replacement;
    store(profile_name, profile, &bundle)?;
    Ok(bundle.access_token)
}

pub async fn login(
    profile_name: &str,
    profile: &Profile,
    device_code: bool,
    channel_history: bool,
    out: &Output,
) -> Result<TokenBundle, AppError> {
    check_store(profile_name, profile)?;
    let bundle = sign_in(profile, device_code, channel_history, out).await?;
    store(profile_name, profile, &bundle)?;
    Ok(bundle)
}

/// Complete Microsoft sign-in without replacing a saved credential yet.
/// Guided setup verifies this exact token before committing the new connection.
pub async fn sign_in(
    profile: &Profile,
    device_code: bool,
    channel_history: bool,
    out: &Output,
) -> Result<TokenBundle, AppError> {
    profile.require_graph()?;
    let scopes = scopes(channel_history);
    if device_code {
        device_login(profile, scopes, out).await
    } else {
        browser_login(profile, scopes, out).await
    }
}

/// Save a verified sign-in with its config; restore the previous credential if config fails.
pub fn save_verified_login<T>(
    profile_name: &str,
    profile: &Profile,
    bundle: &TokenBundle,
    save_config: impl FnOnce() -> Result<T, AppError>,
) -> Result<T, AppError> {
    commit_login(
        &entry_for(profile_name, Some(profile))?,
        bundle,
        save_config,
    )
}

fn commit_login<T>(
    credential: &keyring::Entry,
    bundle: &TokenBundle,
    save_config: impl FnOnce() -> Result<T, AppError>,
) -> Result<T, AppError> {
    let previous = match credential.get_password() {
        Ok(previous) => Some(previous),
        Err(keyring::Error::NoEntry) => None,
        Err(error) => {
            return Err(AppError::Unexpected(format!(
                "Could not preserve the previous sign-in: {error}. No connection settings were saved."
            )));
        }
    };
    let encoded = serde_json::to_string(bundle).map_err(|e| AppError::Unexpected(e.to_string()))?;
    credential.set_password(&encoded).map_err(|e| {
        AppError::Unexpected(format!(
            "Could not save the verified sign-in: {e}. No connection settings were saved."
        ))
    })?;
    match save_config() {
        Ok(result) => Ok(result),
        Err(error) => {
            let restored = match previous {
                Some(previous) => credential.set_password(&previous),
                None => match credential.delete_credential() {
                    Ok(()) | Err(keyring::Error::NoEntry) => Ok(()),
                    Err(error) => Err(error),
                },
            };
            match restored {
                Ok(()) => Err(error.with_hint("Connection settings could not be saved; your previous sign-in was preserved.")),
                Err(_) => Err(error.with_hint("Connection settings could not be saved, and the credential store could not restore your previous sign-in. Retry setup to reconnect this profile.")),
            }
        }
    }
}

fn scopes(channel_history: bool) -> &'static str {
    if channel_history {
        CHANNEL_HISTORY_SCOPES
    } else {
        BASE_SCOPES
    }
}

async fn browser_login(
    profile: &Profile,
    scopes: &str,
    out: &Output,
) -> Result<TokenBundle, AppError> {
    let listener = TcpListener::bind("127.0.0.1:0").await?;
    let redirect = format!("http://localhost:{}", listener.local_addr()?.port());
    let mut verifier_bytes = [0u8; 32];
    rand::rng().fill_bytes(&mut verifier_bytes);
    let verifier = base64::engine::general_purpose::URL_SAFE_NO_PAD.encode(verifier_bytes);
    let challenge = base64::engine::general_purpose::URL_SAFE_NO_PAD
        .encode(Sha256::digest(verifier.as_bytes()));
    let mut state_bytes = [0u8; 18];
    rand::rng().fill_bytes(&mut state_bytes);
    let state = base64::engine::general_purpose::URL_SAFE_NO_PAD.encode(state_bytes);
    let mut authorize = url::Url::parse(&format!(
        "https://login.microsoftonline.com/{}/oauth2/v2.0/authorize",
        profile.tenant
    ))
    .map_err(|e| AppError::Unexpected(e.to_string()))?;
    authorize
        .query_pairs_mut()
        .append_pair("client_id", &profile.client_id)
        .append_pair("response_type", "code")
        .append_pair("redirect_uri", &redirect)
        .append_pair("response_mode", "query")
        .append_pair("scope", scopes)
        .append_pair("code_challenge", &challenge)
        .append_pair("code_challenge_method", "S256")
        .append_pair("state", &state);
    out.note("Opening Microsoft sign-in in your browser…");
    out.note(format!(
        "If it does not open, visit:\n{}",
        authorize.as_str()
    ));
    open::that(authorize.as_str())
        .map_err(|e| AppError::Unexpected(format!("could not open a browser: {e}")))?;

    let (mut socket, _) = tokio::time::timeout(Duration::from_secs(300), listener.accept())
        .await
        .map_err(|_| AppError::Auth("browser sign-in timed out after 5 minutes".into()))??;
    let mut bytes = vec![0; 8192];
    let count = socket.read(&mut bytes).await?;
    let request = String::from_utf8_lossy(&bytes[..count]);
    let target = request
        .split_whitespace()
        .nth(1)
        .ok_or_else(|| AppError::Auth("invalid browser callback".into()))?;
    let callback = url::Url::parse(&format!("http://localhost{target}"))
        .map_err(|e| AppError::Auth(e.to_string()))?;
    let params: HashMap<_, _> = callback.query_pairs().into_owned().collect();
    let ok = params.contains_key("code");
    let page = if ok {
        "Sign-in complete. You can close this tab and return to teams."
    } else {
        "Sign-in did not complete. Return to the terminal for details."
    };
    let body = format!(
        "<html><body style=\"font-family:system-ui;max-width:42rem;margin:10vh auto;padding:2rem\"><h1>{page}</h1></body></html>"
    );
    let response = format!(
        "HTTP/1.1 200 OK\r\nContent-Type: text/html; charset=utf-8\r\nContent-Length: {}\r\nConnection: close\r\n\r\n{body}",
        body.len()
    );
    socket.write_all(response.as_bytes()).await?;
    if params.get("state") != Some(&state) {
        return Err(AppError::Auth(
            "sign-in callback state did not match".into(),
        ));
    }
    if let Some(error) = params
        .get("error_description")
        .or_else(|| params.get("error"))
    {
        return Err(AppError::Auth(error.clone()));
    }
    let code = params
        .get("code")
        .ok_or_else(|| AppError::Auth("Microsoft did not return an authorization code".into()))?;
    let response = reqwest::Client::new()
        .post(token_url(profile))
        .form(&[
            ("client_id", profile.client_id.as_str()),
            ("grant_type", "authorization_code"),
            ("code", code.as_str()),
            ("redirect_uri", redirect.as_str()),
            ("code_verifier", verifier.as_str()),
            ("scope", scopes),
        ])
        .send()
        .await
        .map_err(|e| AppError::Unexpected(format!("sign-in service is unreachable: {e}")))?;
    parse_token_response(response).await
}

#[derive(Debug, Deserialize)]
struct DeviceCode {
    device_code: String,
    user_code: String,
    verification_uri: String,
    expires_in: u64,
    interval: Option<u64>,
    message: Option<String>,
}

async fn device_login(
    profile: &Profile,
    scopes: &str,
    out: &Output,
) -> Result<TokenBundle, AppError> {
    let response = reqwest::Client::new()
        .post(format!(
            "https://login.microsoftonline.com/{}/oauth2/v2.0/devicecode",
            profile.tenant
        ))
        .form(&[("client_id", profile.client_id.as_str()), ("scope", scopes)])
        .send()
        .await
        .map_err(|e| AppError::Unexpected(format!("sign-in service is unreachable: {e}")))?;
    if !response.status().is_success() {
        return Err(oauth_response_error(response).await);
    }
    let device: DeviceCode = response
        .json()
        .await
        .map_err(|e| AppError::Auth(format!("invalid device-code response: {e}")))?;
    out.note(device.message.clone().unwrap_or_else(|| {
        format!(
            "Open {} and enter {}",
            device.verification_uri, device.user_code
        )
    }));
    let deadline = now() + device.expires_in;
    let interval = device.interval.unwrap_or(5);
    while now() < deadline {
        tokio::time::sleep(Duration::from_secs(interval)).await;
        let response = reqwest::Client::new()
            .post(token_url(profile))
            .form(&[
                ("grant_type", "urn:ietf:params:oauth:grant-type:device_code"),
                ("client_id", profile.client_id.as_str()),
                ("device_code", device.device_code.as_str()),
            ])
            .send()
            .await
            .map_err(|e| AppError::Unexpected(e.to_string()))?;
        if response.status().is_success() {
            return parse_token_response(response).await;
        }
        let status = response.status();
        let error: OAuthError = response.json().await.unwrap_or(OAuthError {
            error: "unknown_error".into(),
            error_description: None,
        });
        if error.error == "authorization_pending" {
            continue;
        }
        if error.error == "slow_down" {
            tokio::time::sleep(Duration::from_secs(5)).await;
            continue;
        }
        return Err(AppError::Auth(
            error
                .error_description
                .unwrap_or_else(|| format!("{} ({status})", error.error)),
        ));
    }
    Err(AppError::Auth("device-code sign-in expired".into()))
}

fn token_url(profile: &Profile) -> String {
    format!(
        "https://login.microsoftonline.com/{}/oauth2/v2.0/token",
        profile.tenant
    )
}

async fn parse_token_response(response: reqwest::Response) -> Result<TokenBundle, AppError> {
    if !response.status().is_success() {
        return Err(oauth_response_error(response).await);
    }
    let token: TokenResponse = response
        .json()
        .await
        .map_err(|e| AppError::Auth(format!("invalid token response: {e}")))?;
    Ok(TokenBundle {
        access_token: token.access_token,
        refresh_token: token.refresh_token,
        expires_at: now() + token.expires_in,
        scope: token.scope,
    })
}

async fn oauth_response_error(response: reqwest::Response) -> AppError {
    let status = response.status();
    let error: Option<OAuthError> = response.json().await.ok();
    AppError::Auth(
        error
            .and_then(|e| e.error_description.or(Some(e.error)))
            .unwrap_or_else(|| format!("Microsoft sign-in failed with {status}")),
    )
}

#[cfg(test)]
mod tests {
    use super::{BASE_SCOPES, CHANNEL_HISTORY_SCOPE, scopes};

    fn bundle() -> super::TokenBundle {
        super::TokenBundle {
            access_token: "new-synthetic-access".into(),
            refresh_token: Some("new-synthetic-refresh".into()),
            expires_at: u64::MAX,
            scope: Some(BASE_SCOPES.into()),
        }
    }

    #[test]
    fn failed_config_save_restores_the_previous_protected_credential() {
        let credential =
            keyring::Entry::new_with_credential(Box::new(keyring::mock::MockCredential::default()));
        credential
            .set_password("previous-protected-credential")
            .unwrap();
        let error = super::commit_login(&credential, &bundle(), || {
            assert!(
                credential
                    .get_password()
                    .unwrap()
                    .contains("new-synthetic-access")
            );
            Err::<(), _>(crate::error::AppError::Io(std::io::Error::from(
                std::io::ErrorKind::PermissionDenied,
            )))
        })
        .unwrap_err();
        assert!(error.to_string().contains("previous sign-in was preserved"));
        assert_eq!(
            credential.get_password().unwrap(),
            "previous-protected-credential"
        );
    }

    #[test]
    fn failed_config_save_removes_a_new_credential_and_success_keeps_it() {
        let credential =
            keyring::Entry::new_with_credential(Box::new(keyring::mock::MockCredential::default()));
        assert!(
            super::commit_login(&credential, &bundle(), || {
                Err::<(), _>(crate::error::AppError::Unexpected(
                    "config write failed".into(),
                ))
            })
            .is_err()
        );
        assert!(matches!(
            credential.get_password(),
            Err(keyring::Error::NoEntry)
        ));
        assert_eq!(
            super::commit_login(&credential, &bundle(), || Ok("saved-config")).unwrap(),
            "saved-config"
        );
        let saved: super::TokenBundle =
            serde_json::from_str(&credential.get_password().unwrap()).unwrap();
        assert_eq!(saved.access_token, "new-synthetic-access");
        assert_eq!(
            saved.refresh_token.as_deref(),
            Some("new-synthetic-refresh")
        );
    }

    #[test]
    fn default_login_is_least_privilege() {
        assert!(!BASE_SCOPES.contains(CHANNEL_HISTORY_SCOPE));
        assert!(
            BASE_SCOPES
                .split_whitespace()
                .any(|scope| scope == "User.ReadBasic.All")
        );
        assert!(
            !BASE_SCOPES
                .split_whitespace()
                .any(|scope| scope == "User.Read.All")
        );
        assert_eq!(scopes(false), BASE_SCOPES);
    }

    #[test]
    fn channel_history_is_explicitly_opted_in() {
        assert!(scopes(true).contains(CHANNEL_HISTORY_SCOPE));
    }

    #[cfg(target_os = "linux")]
    #[test]
    fn missing_secret_service_is_treated_as_an_empty_store() {
        let error = keyring::Error::PlatformFailure(Box::new(std::io::Error::other(
            "The name org.freedesktop.secrets was not provided by any .service files",
        )));

        assert!(super::secret_service_is_unavailable(&error));
    }
}