feat(provider): add Ollama client implementation in new providers crate

- Introduce `owlen-providers` crate with Cargo.toml and lib entry.
- Expose `OllamaClient` handling HTTP communication, health checks, model listing, and streaming generation.
- Implement request building, endpoint handling, and error mapping.
- Parse Ollama tags response and generation stream lines into core types.
- Add shared module re-exports for easy integration with the provider layer.

Cargo.toml

@@ -4,6 +4,7 @@ members = [
     "crates/owlen-core",
     "crates/owlen-tui",
     "crates/owlen-cli",
+    "crates/owlen-providers",
     "crates/owlen-mcp-server",
     "crates/owlen-mcp-llm-server",
     "crates/owlen-mcp-client",

crates/owlen-providers/Cargo.toml

@@ -0,0 +1,20 @@
+[package]
+name = "owlen-providers"
+version.workspace = true
+edition.workspace = true
+authors.workspace = true
+license.workspace = true
+repository.workspace = true
+homepage.workspace = true
+description = "Provider implementations for OWLEN"
+
+[dependencies]
+owlen-core = { path = "../owlen-core" }
+anyhow = { workspace = true }
+async-trait = { workspace = true }
+futures = { workspace = true }
+serde = { workspace = true }
+serde_json = { workspace = true }
+tokio = { workspace = true }
+tokio-stream = { workspace = true }
+reqwest = { package = "reqwest", version = "0.11", features = ["json", "stream"] }

crates/owlen-providers/src/lib.rs

@@ -0,0 +1,3 @@
+//! Provider implementations for OWLEN.
+
+pub mod ollama;

crates/owlen-providers/src/ollama/mod.rs

@@ -0,0 +1,3 @@
+pub mod shared;
+
+pub use shared::OllamaClient;

crates/owlen-providers/src/ollama/shared.rs

@@ -0,0 +1,360 @@
+use std::collections::HashMap;
+use std::time::Duration;
+
+use futures::StreamExt;
+use owlen_core::provider::{
+    GenerateChunk, GenerateRequest, GenerateStream, ModelInfo, ProviderMetadata, ProviderStatus,
+};
+use owlen_core::{Error as CoreError, Result as CoreResult};
+use reqwest::{Client, Method, StatusCode, Url};
+use serde::Deserialize;
+use serde_json::{Map as JsonMap, Value};
+use tokio::sync::mpsc;
+use tokio_stream::wrappers::ReceiverStream;
+
+const DEFAULT_TIMEOUT_SECS: u64 = 60;
+
+/// Shared Ollama HTTP client used by both local and cloud providers.
+#[derive(Clone)]
+pub struct OllamaClient {
+    http: Client,
+    base_url: Url,
+    api_key: Option<String>,
+    provider_metadata: ProviderMetadata,
+}
+
+impl OllamaClient {
+    /// Create a new client with the given base URL and optional API key.
+    pub fn new(
+        base_url: impl AsRef<str>,
+        api_key: Option<String>,
+        provider_metadata: ProviderMetadata,
+    ) -> CoreResult<Self> {
+        let base_url = Url::parse(base_url.as_ref())
+            .map_err(|err| CoreError::Config(format!("invalid base url: {}", err)))?;
+
+        let http = Client::builder()
+            .timeout(Duration::from_secs(DEFAULT_TIMEOUT_SECS))
+            .build()
+            .map_err(map_reqwest_error)?;
+
+        Ok(Self {
+            http,
+            base_url,
+            api_key,
+            provider_metadata,
+        })
+    }
+
+    /// Provider metadata associated with this client.
+    pub fn metadata(&self) -> &ProviderMetadata {
+        &self.provider_metadata
+    }
+
+    /// Perform a basic health check to determine provider availability.
+    pub async fn health_check(&self) -> CoreResult<ProviderStatus> {
+        let url = self.endpoint("api/tags")?;
+
+        let response = self
+            .request(Method::GET, url)
+            .send()
+            .await
+            .map_err(map_reqwest_error)?;
+
+        match response.status() {
+            status if status.is_success() => Ok(ProviderStatus::Available),
+            StatusCode::UNAUTHORIZED | StatusCode::FORBIDDEN => Ok(ProviderStatus::RequiresSetup),
+            _ => Ok(ProviderStatus::Unavailable),
+        }
+    }
+
+    /// Fetch the available models from the Ollama API.
+    pub async fn list_models(&self) -> CoreResult<Vec<ModelInfo>> {
+        let url = self.endpoint("api/tags")?;
+
+        let response = self
+            .request(Method::GET, url)
+            .send()
+            .await
+            .map_err(map_reqwest_error)?;
+
+        let status = response.status();
+        let bytes = response.bytes().await.map_err(map_reqwest_error)?;
+
+        if !status.is_success() {
+            let body = String::from_utf8_lossy(&bytes);
+            return Err(CoreError::Provider(anyhow::anyhow!(
+                "Ollama tags request failed: HTTP {} - {}",
+                status,
+                body
+            )));
+        }
+
+        let payload: TagsResponse =
+            serde_json::from_slice(&bytes).map_err(CoreError::Serialization)?;
+
+        let models = payload
+            .models
+            .into_iter()
+            .map(|model| self.parse_model_info(model))
+            .collect();
+
+        Ok(models)
+    }
+
+    /// Request a streaming generation session from Ollama.
+    pub async fn generate_stream(&self, request: GenerateRequest) -> CoreResult<GenerateStream> {
+        let url = self.endpoint("api/generate")?;
+
+        let body = self.build_generate_body(request);
+
+        let response = self
+            .request(Method::POST, url)
+            .json(&body)
+            .send()
+            .await
+            .map_err(map_reqwest_error)?;
+
+        let status = response.status();
+
+        if !status.is_success() {
+            let bytes = response.bytes().await.map_err(map_reqwest_error)?;
+            let body = String::from_utf8_lossy(&bytes);
+            return Err(CoreError::Provider(anyhow::anyhow!(
+                "Ollama generate request failed: HTTP {} - {}",
+                status,
+                body
+            )));
+        }
+
+        let stream = response.bytes_stream();
+        let (tx, rx) = mpsc::channel::<CoreResult<GenerateChunk>>(32);
+
+        tokio::spawn(async move {
+            let mut stream = stream;
+            let mut buffer: Vec<u8> = Vec::new();
+
+            while let Some(chunk) = stream.next().await {
+                match chunk {
+                    Ok(bytes) => {
+                        buffer.extend_from_slice(&bytes);
+                        while let Some(pos) = buffer.iter().position(|byte| *byte == b'\n') {
+                            let line_bytes: Vec<u8> = buffer.drain(..=pos).collect();
+                            let line = String::from_utf8_lossy(&line_bytes).trim().to_string();
+                            if line.is_empty() {
+                                continue;
+                            }
+
+                            match parse_stream_line(&line) {
+                                Ok(item) => {
+                                    if tx.send(Ok(item)).await.is_err() {
+                                        return;
+                                    }
+                                }
+                                Err(err) => {
+                                    let _ = tx.send(Err(err)).await;
+                                    return;
+                                }
+                            }
+                        }
+                    }
+                    Err(err) => {
+                        let _ = tx.send(Err(map_reqwest_error(err))).await;
+                        return;
+                    }
+                }
+            }
+
+            if !buffer.is_empty() {
+                let line = String::from_utf8_lossy(&buffer).trim().to_string();
+                if !line.is_empty() {
+                    match parse_stream_line(&line) {
+                        Ok(item) => {
+                            let _ = tx.send(Ok(item)).await;
+                        }
+                        Err(err) => {
+                            let _ = tx.send(Err(err)).await;
+                        }
+                    }
+                }
+            }
+        });
+
+        let stream = ReceiverStream::new(rx);
+        Ok(Box::pin(stream))
+    }
+
+    fn request(&self, method: Method, url: Url) -> reqwest::RequestBuilder {
+        let mut builder = self.http.request(method, url);
+        if let Some(api_key) = &self.api_key {
+            builder = builder.bearer_auth(api_key);
+        }
+        builder
+    }
+
+    fn endpoint(&self, path: &str) -> CoreResult<Url> {
+        self.base_url
+            .join(path)
+            .map_err(|err| CoreError::Config(format!("invalid endpoint '{}': {}", path, err)))
+    }
+
+    fn build_generate_body(&self, request: GenerateRequest) -> Value {
+        let GenerateRequest {
+            model,
+            prompt,
+            context,
+            parameters,
+            metadata,
+        } = request;
+
+        let mut body = JsonMap::new();
+        body.insert("model".into(), Value::String(model));
+        body.insert("stream".into(), Value::Bool(true));
+
+        if let Some(prompt) = prompt {
+            body.insert("prompt".into(), Value::String(prompt));
+        }
+
+        if !context.is_empty() {
+            let items = context.into_iter().map(Value::String).collect();
+            body.insert("context".into(), Value::Array(items));
+        }
+
+        if !parameters.is_empty() {
+            body.insert("options".into(), Value::Object(to_json_map(parameters)));
+        }
+
+        if !metadata.is_empty() {
+            body.insert("metadata".into(), Value::Object(to_json_map(metadata)));
+        }
+
+        Value::Object(body)
+    }
+
+    fn parse_model_info(&self, model: OllamaModel) -> ModelInfo {
+        let mut metadata = HashMap::new();
+
+        if let Some(digest) = model.digest {
+            metadata.insert("digest".to_string(), Value::String(digest));
+        }
+        if let Some(modified) = model.modified_at {
+            metadata.insert("modified_at".to_string(), Value::String(modified));
+        }
+        if let Some(details) = model.details {
+            let mut details_map = JsonMap::new();
+            if let Some(format) = details.format {
+                details_map.insert("format".into(), Value::String(format));
+            }
+            if let Some(family) = details.family {
+                details_map.insert("family".into(), Value::String(family));
+            }
+            if let Some(parameter_size) = details.parameter_size {
+                details_map.insert("parameter_size".into(), Value::String(parameter_size));
+            }
+            if let Some(quantisation) = details.quantization_level {
+                details_map.insert("quantization_level".into(), Value::String(quantisation));
+            }
+
+            if !details_map.is_empty() {
+                metadata.insert("details".to_string(), Value::Object(details_map));
+            }
+        }
+
+        ModelInfo {
+            name: model.name,
+            size_bytes: model.size,
+            capabilities: Vec::new(),
+            description: None,
+            provider: self.provider_metadata.clone(),
+            metadata,
+        }
+    }
+}
+
+#[derive(Debug, Deserialize)]
+struct TagsResponse {
+    #[serde(default)]
+    models: Vec<OllamaModel>,
+}
+
+#[derive(Debug, Deserialize)]
+struct OllamaModel {
+    name: String,
+    #[serde(default)]
+    size: Option<u64>,
+    #[serde(default)]
+    digest: Option<String>,
+    #[serde(default)]
+    modified_at: Option<String>,
+    #[serde(default)]
+    details: Option<OllamaModelDetails>,
+}
+
+#[derive(Debug, Deserialize)]
+struct OllamaModelDetails {
+    #[serde(default)]
+    format: Option<String>,
+    #[serde(default)]
+    family: Option<String>,
+    #[serde(default)]
+    parameter_size: Option<String>,
+    #[serde(default)]
+    quantization_level: Option<String>,
+}
+
+fn to_json_map(source: HashMap<String, Value>) -> JsonMap<String, Value> {
+    source.into_iter().collect()
+}
+
+fn to_metadata_map(value: &Value) -> HashMap<String, Value> {
+    let mut metadata = HashMap::new();
+
+    if let Value::Object(obj) = value {
+        for (key, item) in obj {
+            if key == "response" || key == "done" {
+                continue;
+            }
+            metadata.insert(key.clone(), item.clone());
+        }
+    }
+
+    metadata
+}
+
+fn parse_stream_line(line: &str) -> CoreResult<GenerateChunk> {
+    let value: Value = serde_json::from_str(line).map_err(CoreError::Serialization)?;
+
+    if let Some(error) = value.get("error").and_then(Value::as_str) {
+        return Err(CoreError::Provider(anyhow::anyhow!(
+            "ollama generation error: {}",
+            error
+        )));
+    }
+
+    let mut chunk = GenerateChunk {
+        text: value
+            .get("response")
+            .and_then(Value::as_str)
+            .map(str::to_string),
+        is_final: value.get("done").and_then(Value::as_bool).unwrap_or(false),
+        metadata: to_metadata_map(&value),
+    };
+
+    if chunk.is_final && chunk.text.is_none() && chunk.metadata.is_empty() {
+        chunk
+            .metadata
+            .insert("status".into(), Value::String("done".into()));
+    }
+
+    Ok(chunk)
+}
+
+fn map_reqwest_error(err: reqwest::Error) -> CoreError {
+    if err.is_timeout() {
+        CoreError::Timeout(err.to_string())
+    } else if err.is_connect() || err.is_request() {
+        CoreError::Network(err.to_string())
+    } else {
+        CoreError::Provider(err.into())
+    }
+}