github-rust 0.1.0

use crate::error::*;
use crate::github::client::GitHubClient;
use crate::github::graphql::{self, Repository};
use crate::github::{rest, search};

/// High-level service for GitHub API operations.
///
/// `GitHubService` is the main entry point for interacting with the GitHub API.
/// It provides a simple, ergonomic interface with automatic fallback from GraphQL
/// to REST API when needed.
///
/// # Authentication
///
/// The service automatically detects the `GITHUB_TOKEN` environment variable.
/// - **With token**: 5,000 requests/hour, access to private repos
/// - **Without token**: 60 requests/hour, public repos only
///
/// # Example
///
/// ```no_run
/// use github_rust::GitHubService;
///
/// # async fn example() -> github_rust::Result<()> {
/// let service = GitHubService::new()?;
///
/// // Check authentication status
/// if service.has_token() {
///     println!("Authenticated with higher rate limits");
/// }
///
/// // Get repository information
/// let repo = service.get_repository_info("rust-lang", "rust").await?;
/// println!("{} has {} stars", repo.name_with_owner, repo.stargazer_count);
/// # Ok(())
/// # }
/// ```
pub struct GitHubService {
    /// The underlying HTTP client with connection pooling.
    pub client: GitHubClient,
}

impl GitHubService {
    /// Creates a new GitHub service with default configuration.
    ///
    /// Automatically detects `GITHUB_TOKEN` from environment variables.
    ///
    /// # Errors
    ///
    /// Returns an error if the HTTP client cannot be initialized (rare, typically
    /// indicates system-level TLS or network configuration issues).
    ///
    /// # Example
    ///
    /// ```no_run
    /// use github_rust::GitHubService;
    ///
    /// let service = GitHubService::new()?;
    /// # Ok::<(), github_rust::GitHubError>(())
    /// ```
    #[must_use = "Creating a service without using it is wasteful"]
    pub fn new() -> Result<Self> {
        let client = GitHubClient::new()?;
        Ok(Self { client })
    }

    /// Creates a GitHub service with a custom client.
    ///
    /// Useful for testing or when you need custom HTTP configuration.
    #[must_use]
    pub fn with_client(client: GitHubClient) -> Self {
        Self { client }
    }

    /// Fetches detailed information about a GitHub repository.
    ///
    /// Uses GraphQL API by default for efficiency, automatically falls back to
    /// REST API if GraphQL fails (e.g., when no token is provided for certain queries).
    ///
    /// # Arguments
    ///
    /// * `owner` - Repository owner (username or organization)
    /// * `name` - Repository name
    ///
    /// # Returns
    ///
    /// Full repository details including stars, forks, language, topics, license, etc.
    ///
    /// # Errors
    ///
    /// * [`GitHubError::NotFoundError`] - Repository doesn't exist or is private without auth
    /// * [`GitHubError::RateLimitError`] - API rate limit exceeded
    /// * [`GitHubError::AccessBlockedError`] - Repository access blocked by GitHub
    /// * [`GitHubError::DmcaBlockedError`] - Repository blocked for legal reasons
    ///
    /// # Example
    ///
    /// ```no_run
    /// # use github_rust::GitHubService;
    /// # async fn example() -> github_rust::Result<()> {
    /// let service = GitHubService::new()?;
    /// let repo = service.get_repository_info("microsoft", "vscode").await?;
    ///
    /// println!("Name: {}", repo.name_with_owner);
    /// println!("Stars: {}", repo.stargazer_count);
    /// println!("Forks: {}", repo.fork_count);
    /// if let Some(lang) = &repo.primary_language {
    ///     println!("Language: {}", lang.name);
    /// }
    /// # Ok(())
    /// # }
    /// ```
    pub async fn get_repository_info(&self, owner: &str, name: &str) -> Result<Repository> {
        match graphql::get_repository_info(&self.client, owner, name).await {
            Ok(repo) => Ok(repo),
            Err(GitHubError::AuthenticationError(_)) if !self.client.has_token() => {
                tracing::debug!("GraphQL auth failed without token, falling back to REST");
                rest::get_repository_info(&self.client, owner, name).await
            }
            Err(e) => {
                tracing::debug!("GraphQL failed ({}), falling back to REST", e);
                rest::get_repository_info(&self.client, owner, name).await
            }
        }
    }

    /// Searches for recently created repositories with filtering options.
    ///
    /// Finds repositories created within the specified time period, filtered by
    /// language and minimum star count. Results are sorted by stars (descending).
    ///
    /// # Arguments
    ///
    /// * `days_back` - Search for repos created in the last N days
    /// * `limit` - Maximum number of results (capped at 1000)
    /// * `language` - Optional programming language filter (e.g., "rust", "python", "C++")
    /// * `min_stars` - Minimum number of stars required
    ///
    /// # Errors
    ///
    /// * [`GitHubError::InvalidInput`] - Invalid language parameter
    /// * [`GitHubError::RateLimitError`] - API rate limit exceeded
    /// * [`GitHubError::AuthenticationError`] - Token required for this operation
    ///
    /// # Example
    ///
    /// ```no_run
    /// # use github_rust::GitHubService;
    /// # async fn example() -> github_rust::Result<()> {
    /// let service = GitHubService::new()?;
    ///
    /// // Find Rust repos created in last 30 days with 50+ stars
    /// let repos = service.search_repositories(
    ///     30,           // days back
    ///     100,          // limit
    ///     Some("rust"), // language
    ///     50,           // min stars
    /// ).await?;
    ///
    /// for repo in repos {
    ///     println!("{}: {} stars", repo.name_with_owner, repo.stargazer_count);
    /// }
    /// # Ok(())
    /// # }
    /// ```
    pub async fn search_repositories(
        &self,
        days_back: u32,
        limit: usize,
        language: Option<&str>,
        min_stars: u32,
    ) -> Result<Vec<search::SearchRepository>> {
        search::search_repositories(&self.client, days_back, limit, language, min_stars).await
    }

    /// Checks the current GitHub API rate limit status.
    ///
    /// Useful for monitoring API usage and implementing backoff strategies.
    ///
    /// # Returns
    ///
    /// Rate limit information including limit, remaining requests, and reset time.
    ///
    /// # Example
    ///
    /// ```no_run
    /// # use github_rust::GitHubService;
    /// # async fn example() -> github_rust::Result<()> {
    /// let service = GitHubService::new()?;
    /// let limits = service.check_rate_limit().await?;
    ///
    /// println!("Remaining: {}/{}", limits.remaining, limits.limit);
    /// println!("Resets at: {}", limits.reset_datetime());
    ///
    /// if limits.is_exceeded() {
    ///     println!("Rate limited! Wait {:?}", limits.time_until_reset());
    /// }
    /// # Ok(())
    /// # }
    /// ```
    pub async fn check_rate_limit(&self) -> Result<crate::github::client::RateLimit> {
        self.client.check_rate_limit().await
    }

    /// Returns whether a GitHub token is configured.
    ///
    /// Useful for conditional logic based on authentication status.
    ///
    /// # Example
    ///
    /// ```no_run
    /// # use github_rust::GitHubService;
    /// let service = GitHubService::new()?;
    ///
    /// if service.has_token() {
    ///     println!("Authenticated: 5000 requests/hour");
    /// } else {
    ///     println!("Anonymous: 60 requests/hour");
    /// }
    /// # Ok::<(), github_rust::GitHubError>(())
    /// ```
    #[must_use]
    pub fn has_token(&self) -> bool {
        self.client.has_token()
    }

    /// Gets all repositories starred by the authenticated user.
    ///
    /// Requires authentication via `GITHUB_TOKEN`.
    ///
    /// # Returns
    ///
    /// List of repository full names in "owner/repo" format.
    /// Limited to 10,000 repositories maximum.
    ///
    /// # Errors
    ///
    /// * [`GitHubError::AuthenticationError`] - No token or invalid token
    /// * [`GitHubError::RateLimitError`] - API rate limit exceeded
    ///
    /// # Example
    ///
    /// ```no_run
    /// # use github_rust::GitHubService;
    /// # async fn example() -> github_rust::Result<()> {
    /// let service = GitHubService::new()?;
    /// let starred = service.get_user_starred_repositories().await?;
    ///
    /// println!("You have starred {} repositories", starred.len());
    /// for repo in starred.iter().take(5) {
    ///     println!("  - {}", repo);
    /// }
    /// # Ok(())
    /// # }
    /// ```
    pub async fn get_user_starred_repositories(&self) -> Result<Vec<String>> {
        rest::get_user_starred_repositories(&self.client).await
    }

    /// Gets the profile of the authenticated user.
    ///
    /// Requires authentication via `GITHUB_TOKEN`.
    ///
    /// # Errors
    ///
    /// * [`GitHubError::AuthenticationError`] - No token or invalid token
    ///
    /// # Example
    ///
    /// ```no_run
    /// # use github_rust::GitHubService;
    /// # async fn example() -> github_rust::Result<()> {
    /// let service = GitHubService::new()?;
    /// let profile = service.get_user_profile().await?;
    ///
    /// println!("Logged in as: {}", profile.login);
    /// if let Some(name) = profile.name {
    ///     println!("Name: {}", name);
    /// }
    /// # Ok(())
    /// # }
    /// ```
    pub async fn get_user_profile(&self) -> Result<rest::UserProfile> {
        rest::get_user_profile(&self.client).await
    }

    /// Gets users who starred a repository with timestamps.
    ///
    /// Returns stargazers with the date they starred the repository.
    /// Supports pagination for repositories with many stars.
    ///
    /// # Arguments
    ///
    /// * `owner` - Repository owner
    /// * `name` - Repository name
    /// * `per_page` - Results per page (max 100, default 30)
    /// * `page` - Page number (default 1)
    ///
    /// # Errors
    ///
    /// * [`GitHubError::NotFoundError`] - Repository not found
    /// * [`GitHubError::RateLimitError`] - API rate limit exceeded
    ///
    /// # Example
    ///
    /// ```no_run
    /// # use github_rust::GitHubService;
    /// # async fn example() -> github_rust::Result<()> {
    /// let service = GitHubService::new()?;
    ///
    /// // Get first 100 stargazers
    /// let stargazers = service.get_repository_stargazers(
    ///     "rust-lang", "rust",
    ///     Some(100),  // per_page
    ///     Some(1),    // page
    /// ).await?;
    ///
    /// for sg in stargazers {
    ///     println!("{} starred at {}", sg.user.login, sg.starred_at);
    /// }
    /// # Ok(())
    /// # }
    /// ```
    pub async fn get_repository_stargazers(
        &self,
        owner: &str,
        name: &str,
        per_page: Option<u32>,
        page: Option<u32>,
    ) -> Result<Vec<crate::github::types::StargazerWithDate>> {
        rest::get_repository_stargazers(&self.client, owner, name, per_page, page).await
    }
}

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

    #[test]
    fn test_github_service_creation() {
        let service = GitHubService::new();
        assert!(service.is_ok());
    }

    #[test]
    fn test_github_service_has_token_detection() {
        let service = GitHubService::new().unwrap();
        // Token detection should work without panicking
        let _has_token = service.has_token();
    }
}