rust-x402 0.3.0

//! HTTP client with x402 payment support

use crate::types::*;
use crate::{Result, X402Error};
use http;
use reqwest::{Client, Response};
use std::time::Duration;

/// HTTP client with x402 payment support
#[derive(Debug, Clone)]
pub struct X402Client {
    /// Underlying HTTP client
    client: Client,
    /// Default facilitator configuration
    facilitator_config: FacilitatorConfig,
}

impl X402Client {
    /// Create a new x402 client
    pub fn new() -> Result<Self> {
        Self::with_config(FacilitatorConfig::default())
    }

    /// Create a new x402 client with custom configuration
    pub fn with_config(facilitator_config: FacilitatorConfig) -> Result<Self> {
        let client = Client::builder()
            .timeout(Duration::from_secs(30))
            .build()
            .map_err(|e| X402Error::config(format!("Failed to create HTTP client: {}", e)))?;

        Ok(Self {
            client,
            facilitator_config,
        })
    }

    /// Create a GET request
    pub fn get(&self, url: &str) -> X402RequestBuilder<'_> {
        let mut builder = X402RequestBuilder::new(self, self.client.get(url));
        builder.method = "GET".to_string();
        builder.url = url.to_string();
        builder
    }

    /// Create a POST request
    pub fn post(&self, url: &str) -> X402RequestBuilder<'_> {
        let mut builder = X402RequestBuilder::new(self, self.client.post(url));
        builder.method = "POST".to_string();
        builder.url = url.to_string();
        builder
    }

    /// Create a PUT request
    pub fn put(&self, url: &str) -> X402RequestBuilder<'_> {
        let mut builder = X402RequestBuilder::new(self, self.client.put(url));
        builder.method = "PUT".to_string();
        builder.url = url.to_string();
        builder
    }

    /// Create a DELETE request
    pub fn delete(&self, url: &str) -> X402RequestBuilder<'_> {
        let mut builder = X402RequestBuilder::new(self, self.client.delete(url));
        builder.method = "DELETE".to_string();
        builder.url = url.to_string();
        builder
    }

    /// Handle a 402 payment required response with automatic retry
    pub async fn handle_payment_required(
        &self,
        response: Response,
        payment_payload: &PaymentPayload,
    ) -> Result<Response> {
        if response.status() != 402 {
            return Ok(response);
        }

        let original_url = response.url().to_string();
        let payment_requirements: PaymentRequirementsResponse = response.json().await?;

        // Verify the payment with the facilitator
        let facilitator = super::facilitator::FacilitatorClient::new(
            self.facilitator_config.clone(),
        )
        .map_err(|e| {
            X402Error::facilitator_error(format!("Failed to create facilitator client: {}", e))
        })?;

        for requirements in &payment_requirements.accepts {
            let verify_response = facilitator.verify(payment_payload, requirements).await?;

            if verify_response.is_valid {
                // Retry the original request with payment
                let payment_header = payment_payload.to_base64()?;

                // Create a new request with payment header
                let new_response = self
                    .client
                    .get(&original_url)
                    .header("X-PAYMENT", payment_header)
                    .send()
                    .await?;

                return Ok(new_response);
            }
        }

        Err(X402Error::payment_verification_failed(
            "Payment verification failed for all requirements",
        ))
    }

    /// Make a request with automatic payment handling
    pub async fn request_with_payment(
        &self,
        method: &str,
        url: &str,
        payment_payload: Option<&PaymentPayload>,
    ) -> Result<Response> {
        let mut request_builder = match method.to_uppercase().as_str() {
            "GET" => self.get(url),
            "POST" => self.post(url),
            "PUT" => self.put(url),
            "DELETE" => self.delete(url),
            _ => {
                return Err(X402Error::unexpected(format!(
                    "Unsupported HTTP method: {}",
                    method
                )))
            }
        };

        // Add payment header if provided
        if let Some(payload) = payment_payload {
            let payment_header = payload.to_base64()?;
            request_builder = request_builder.header("X-PAYMENT", payment_header);
        }

        let response = request_builder.send().await?;

        // If we get a 402 and have a payment payload, try to handle it
        if response.status() == 402 {
            if let Some(payload) = payment_payload {
                return self.handle_payment_required(response, payload).await;
            } else {
                // Return the 402 response as-is if no payment payload provided
                return Ok(response);
            }
        }

        Ok(response)
    }

    /// Get the facilitator configuration
    pub fn facilitator_config(&self) -> &FacilitatorConfig {
        &self.facilitator_config
    }

    /// Set a new facilitator configuration
    pub fn with_facilitator_config(mut self, config: FacilitatorConfig) -> Self {
        self.facilitator_config = config;
        self
    }
}

impl Default for X402Client {
    fn default() -> Self {
        Self::with_config(FacilitatorConfig::default()).unwrap_or_else(|_| {
            // Fallback to basic client if configuration fails
            Self {
                client: Client::new(),
                facilitator_config: FacilitatorConfig::default(),
            }
        })
    }
}

/// Request builder for x402 client
#[derive(Debug)]
pub struct X402RequestBuilder<'a> {
    client: &'a X402Client,
    request: reqwest::RequestBuilder,
    method: String,
    url: String,
    _headers: std::collections::HashMap<String, String>,
    _body: Option<Vec<u8>>,
}

impl<'a> X402RequestBuilder<'a> {
    fn new(client: &'a X402Client, request: reqwest::RequestBuilder) -> Self {
        Self {
            client,
            request,
            method: String::new(),
            url: String::new(),
            _headers: std::collections::HashMap::new(),
            _body: None,
        }
    }

    /// Add a header to the request
    pub fn header<K, V>(self, key: K, value: V) -> Self
    where
        reqwest::header::HeaderName: std::convert::TryFrom<K>,
        <reqwest::header::HeaderName as std::convert::TryFrom<K>>::Error: Into<http::Error>,
        reqwest::header::HeaderValue: std::convert::TryFrom<V>,
        <reqwest::header::HeaderValue as std::convert::TryFrom<V>>::Error: Into<http::Error>,
    {
        Self {
            request: self.request.header(key, value),
            ..self
        }
    }

    /// Add multiple headers to the request
    pub fn headers(self, headers: reqwest::header::HeaderMap) -> Self {
        Self {
            request: self.request.headers(headers),
            ..self
        }
    }

    /// Set the request body
    pub fn body(self, body: impl Into<reqwest::Body>) -> Self {
        Self {
            request: self.request.body(body),
            ..self
        }
    }

    /// Set JSON body
    pub fn json<T: serde::Serialize>(self, json: &T) -> Self {
        Self {
            request: self.request.json(json),
            ..self
        }
    }

    /// Set form data
    pub fn form<T: serde::Serialize>(self, form: &T) -> Self {
        Self {
            request: self.request.form(form),
            ..self
        }
    }

    /// Set query parameters
    pub fn query<T: serde::Serialize>(self, query: &T) -> Self {
        Self {
            request: self.request.query(query),
            ..self
        }
    }

    /// Set timeout for the request
    pub fn timeout(self, timeout: Duration) -> Self {
        Self {
            request: self.request.timeout(timeout),
            ..self
        }
    }

    /// Add a payment header to the request
    pub fn payment(self, payment_payload: &PaymentPayload) -> Result<Self> {
        let payment_header = payment_payload.to_base64()?;
        Ok(self.header("X-PAYMENT", &payment_header))
    }

    /// Send the request
    pub async fn send(self) -> Result<Response> {
        self.request.send().await.map_err(X402Error::from)
    }

    /// Send the request and handle x402 payments automatically
    pub async fn send_with_payment(self, payment_payload: &PaymentPayload) -> Result<Response> {
        // Save values before consuming self
        let original_url = self.url.clone();
        let client = self.client.clone();

        let response = self.send().await?;

        if response.status() == 402 {
            // Parse payment requirements from 402 response
            let _payment_requirements: PaymentRequirementsResponse = response.json().await?;

            // Create a new request with payment header
            let payment_header = payment_payload.to_base64()?;

            // Create a new request with payment header
            let new_response = client
                .client
                .get(&original_url)
                .header("X-PAYMENT", &payment_header)
                .send()
                .await?;

            Ok(new_response)
        } else {
            Ok(response)
        }
    }

    /// Send the request and return the response as text
    pub async fn send_and_get_text(self) -> Result<String> {
        let response = self.send().await?;
        response.text().await.map_err(X402Error::from)
    }

    /// Send the request and return the response as JSON
    pub async fn send_and_get_json<T>(self) -> Result<T>
    where
        T: serde::de::DeserializeOwned,
    {
        let response = self.send().await?;
        response.json().await.map_err(X402Error::from)
    }
}

/// Discovery client for finding x402 resources
#[derive(Debug, Clone)]
pub struct DiscoveryClient {
    /// Base URL of the discovery service
    url: String,
    /// HTTP client
    client: Client,
}

impl DiscoveryClient {
    /// Create a new discovery client
    pub fn new(url: impl Into<String>) -> Self {
        let client = Client::new();
        Self {
            url: url.into(),
            client,
        }
    }

    /// Get the default discovery client
    pub fn default_client() -> Self {
        Self::new("https://x402.org/discovery")
    }

    /// Discover resources with optional filters
    pub async fn discover_resources(
        &self,
        filters: Option<DiscoveryFilters>,
    ) -> Result<DiscoveryResponse> {
        let mut request = self.client.get(format!("{}/resources", self.url));

        if let Some(filters) = filters {
            if let Some(resource_type) = filters.resource_type {
                request = request.query(&[("type", resource_type)]);
            }
            if let Some(limit) = filters.limit {
                request = request.query(&[("limit", limit.to_string())]);
            }
            if let Some(offset) = filters.offset {
                request = request.query(&[("offset", offset.to_string())]);
            }
        }

        let response = request.send().await?;

        if !response.status().is_success() {
            return Err(X402Error::facilitator_error(format!(
                "Discovery failed with status: {}",
                response.status()
            )));
        }

        let discovery_response: DiscoveryResponse = response.json().await?;
        Ok(discovery_response)
    }

    /// Get all available resources
    pub async fn get_all_resources(&self) -> Result<DiscoveryResponse> {
        self.discover_resources(None).await
    }

    /// Get resources by type
    pub async fn get_resources_by_type(&self, resource_type: &str) -> Result<DiscoveryResponse> {
        self.discover_resources(Some(DiscoveryFilters {
            resource_type: Some(resource_type.to_string()),
            limit: None,
            offset: None,
        }))
        .await
    }

    /// Get the base URL of this discovery service
    pub fn url(&self) -> &str {
        &self.url
    }
}

/// Filters for discovery requests
#[derive(Debug, Clone)]
pub struct DiscoveryFilters {
    /// Filter by resource type
    pub resource_type: Option<String>,
    /// Maximum number of results
    pub limit: Option<u32>,
    /// Number of results to skip
    pub offset: Option<u32>,
}

impl DiscoveryFilters {
    /// Create new discovery filters
    pub fn new() -> Self {
        Self {
            resource_type: None,
            limit: None,
            offset: None,
        }
    }

    /// Set resource type filter
    pub fn with_resource_type(mut self, resource_type: impl Into<String>) -> Self {
        self.resource_type = Some(resource_type.into());
        self
    }

    /// Set limit
    pub fn with_limit(mut self, limit: u32) -> Self {
        self.limit = Some(limit);
        self
    }

    /// Set offset
    pub fn with_offset(mut self, offset: u32) -> Self {
        self.offset = Some(offset);
        self
    }
}

impl Default for DiscoveryFilters {
    fn default() -> Self {
        Self::new()
    }
}

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

    #[test]
    fn test_client_creation() {
        let client = X402Client::new().unwrap();
        assert_eq!(
            client.facilitator_config().url,
            "https://x402.org/facilitator"
        );
    }

    #[test]
    fn test_client_with_config() {
        let config = FacilitatorConfig::new("https://custom-facilitator.com");
        let client = X402Client::with_config(config).unwrap();
        assert_eq!(
            client.facilitator_config().url,
            "https://custom-facilitator.com"
        );
    }

    #[test]
    fn test_discovery_filters() {
        let filters = DiscoveryFilters::new()
            .with_resource_type("http")
            .with_limit(10)
            .with_offset(0);

        assert_eq!(filters.resource_type, Some("http".to_string()));
        assert_eq!(filters.limit, Some(10));
        assert_eq!(filters.offset, Some(0));
    }

    #[test]
    fn test_discovery_client_creation() {
        let client = DiscoveryClient::new("https://example.com/discovery");
        assert_eq!(client.url(), "https://example.com/discovery");
    }

    #[test]
    fn test_client_with_payment_request() {
        let client = X402Client::new().unwrap();

        // Test that we can create requests with different methods
        let get_request = client.get("https://example.com");
        let post_request = client.post("https://example.com");
        let put_request = client.put("https://example.com");
        let delete_request = client.delete("https://example.com");

        // These should not panic
        assert_eq!(get_request.method, "GET");
        assert_eq!(post_request.method, "POST");
        assert_eq!(put_request.method, "PUT");
        assert_eq!(delete_request.method, "DELETE");
    }

    #[test]
    fn test_discovery_filters_builder() {
        let filters = DiscoveryFilters::new()
            .with_resource_type("http")
            .with_limit(10)
            .with_offset(5);

        assert_eq!(filters.resource_type, Some("http".to_string()));
        assert_eq!(filters.limit, Some(10));
        assert_eq!(filters.offset, Some(5));
    }
}