.devcontainer/devcontainer.json

@@ -12,18 +12,8 @@
     "containerEnv": {
         "SHELL": "/bin/bash"
     },
-    "customizations": {
-        "vscode": {
-            "extensions": ["rust-lang.rust-analyzer", "tamasfe.even-better-toml", "fill-labs.dependi"],
-            "settings": {
-                "[rust]": {
-                    "editor.defaultFormatter": "rust-lang.rust-analyzer",
-                    "editor.formatOnSave": true
-                }
-            }
-        }
-    },
     "workspaceMount": "source=${localWorkspaceFolder},target=/workspaces/herald,type=bind",
     "workspaceFolder": "/workspaces/herald",
+ 	"runArgs": ["--userns=keep-id", "--security-opt", "label=disable"],
     "appPort": [3000]
 }

Cargo.toml

@@ -4,10 +4,14 @@ version = "0.1.0"
 edition = "2024"
 
 [dependencies]
-reqwest = { version = "0.13", features = ["json"] }
+reqwest = { version = "0.12", default-features = false, features = ["json", "rustls-tls"] }
 tokio = { version = "1.52", features = ["full"] }
+tokio-stream = "0.1"
+tokio-util = "0.7"
+futures-util = "0.3"
 serde_json = "1.0"
 serde = { version = "1.0", features = ["derive"] }
+openrouter-rs = "0.10"
 dotenvy = "0.15"
 axum = "0.8"
 anyhow = "1.0"

src/api.rs

@@ -1,9 +1,10 @@
 use axum::body::{Bytes, to_bytes};
-use axum::extract::{FromRef, FromRequest};
-use axum::response::{IntoResponse, Response};
+use axum::extract::{FromRef, FromRequest, State};
+use axum::response::IntoResponse;
 use axum::routing::{get, post};
 use axum::{Json, Router};
 use hmac::{Hmac, KeyInit, Mac};
+use reqwest::StatusCode;
 use serde_json::Value;
 use sha2::Sha256;
 use subtle::ConstantTimeEq;
@@ -31,8 +32,17 @@ async fn root() -> &'static str {
     "Hi, i'm Herald :)"
 }
 
-async fn webhook(WebhookExtract(wb): WebhookExtract) -> Result<Response, AppError> {
-    Ok("lol".into_response())
+async fn webhook(
+    State(app_state): State<AppState>,
+    WebhookExtract(wb): WebhookExtract,
+) -> Result<impl IntoResponse, AppError> {
+    app_state
+        .bot_tx
+        .send(wb)
+        .await
+        .map_err(anyhow::Error::from)?;
+
+    Ok((StatusCode::CREATED, "Task started"))
 }
 
 pub struct WebhookExtract(pub WebhookType);

src/bot.rs

@@ -1,13 +1,117 @@
-use crate::{env::EnvConfig, gitea::WebhookType};
+use serde::Deserialize;
+use std::time::Duration;
+
+use crate::{
+    env::EnvConfig,
+    gitea::{GiteaAPI, WebhookType},
+    open_router::OpenRouterClient,
+};
+
+#[derive(Deserialize, Debug)]
+pub struct ReviewResult {
+    pub reviews: Vec<ReviewItem>,
+    pub comment: String,
+    pub cost: Option<f64>,
+}
+
+#[derive(Deserialize, Debug)]
+pub struct ReviewItem {
+    pub filename: String,
+    pub line: Option<u64>,
+    pub code: String,
+    pub message: String,
+}
+
+/// Map a filename to a markdown language identifier for syntax highlighting.
+fn lang_from_filename(filename: &str) -> &str {
+    match std::path::Path::new(filename)
+        .extension()
+        .and_then(|e| e.to_str())
+        .unwrap_or("")
+    {
+        "rs" => "rust",
+        "py" => "python",
+        "js" | "mjs" => "javascript",
+        "ts" => "typescript",
+        "jsx" => "jsx",
+        "tsx" => "tsx",
+        "go" => "go",
+        "java" => "java",
+        "kt" | "kts" => "kotlin",
+        "scala" => "scala",
+        "c" | "h" => "c",
+        "cpp" | "cc" | "cxx" | "hpp" | "hxx" => "cpp",
+        "rb" => "ruby",
+        "php" => "php",
+        "swift" => "swift",
+        "sh" | "bash" | "zsh" => "bash",
+        "sql" => "sql",
+        "html" | "htm" => "html",
+        "css" => "css",
+        "scss" | "sass" => "scss",
+        "json" => "json",
+        "yaml" | "yml" => "yaml",
+        "xml" => "xml",
+        "toml" => "toml",
+        "md" | "mdx" => "markdown",
+        "dockerfile" | "Dockerfile" => "dockerfile",
+        "Makefile" => "makefile",
+        _ => "",
+    }
+}
 
 pub struct Bot {
     config: EnvConfig,
+    gitea_api: GiteaAPI,
+    open_router_client: OpenRouterClient,
+    http_client: reqwest::Client,
 }
 
 impl Bot {
-    pub fn new(config: EnvConfig) -> Self {
-        Self { config }
+    pub fn new(config: EnvConfig) -> anyhow::Result<Self> {
+        let gitea_timeout = config.gitea_timeout;
+        let open_router_timeout = config.open_router_timeout;
+
+        Ok(Self {
+            gitea_api: GiteaAPI::new(&config.gitea_url, &config.gitea_token, gitea_timeout)?,
+            open_router_client: OpenRouterClient::new(
+                &config.open_router_api_key,
+                &config.open_router_model,
+                open_router_timeout,
+            )?,
+            config,
+            http_client: reqwest::Client::builder()
+                .timeout(Duration::from_secs(gitea_timeout))
+                .build()?,
+        })
     }
 
-    pub async fn exec(&self, webhook: WebhookType) {}
+    pub async fn start(
+        &self,
+        mut rx: tokio::sync::mpsc::Receiver<WebhookType>,
+    ) -> anyhow::Result<()> {
+        while let Some(wb) = rx.recv().await {
+            self.exec(wb).await;
+        }
+
+        Ok(())
+    }
+
+    pub async fn exec(&self, webhook: WebhookType) {
+        let exec_result = match webhook {
+            WebhookType::Review(review_payload) => crate::bot_actions::review::exec_review(
+                &self.gitea_api,
+                &self.open_router_client,
+                &self.http_client,
+                &self.config.open_router_model,
+                review_payload,
+            ),
+        }
+        .await;
+
+        match exec_result {
+            Ok(_) => println!("Task completed"),
+            Err(err) => println!("{}", err),
+        }
+    }
 }

src/bot_actions/mod.rs

@@ -0,0 +1 @@
+pub mod review;

src/bot_actions/review.rs

@@ -0,0 +1,201 @@
+use futures_util::stream::TryStreamExt;
+use tokio::io::AsyncReadExt;
+use tokio_util::io::StreamReader;
+
+use crate::{
+    bot::ReviewResult,
+    consts::{BOT_PROCESS_MSG, MAX_DIFF_SIZE, REVIEW_PROMPT},
+    errors::AppError,
+    gitea::{GiteaAPI, ReviewPayload},
+    open_router::OpenRouterClient,
+};
+
+pub async fn exec_review(
+    gitea_api: &GiteaAPI,
+    open_router_client: &OpenRouterClient,
+    http_client: &reqwest::Client,
+    model: &str,
+    review_payload: ReviewPayload,
+) -> Result<(), AppError> {
+    let new_comment = gitea_api
+        .comment(
+            &BOT_PROCESS_MSG.replace("{model}", model),
+            &review_payload.repository.full_name,
+            review_payload.pull_request.number,
+        )
+        .await?;
+
+    let bot_result: Result<ReviewResult, anyhow::Error> = async {
+        let git_diff =
+            download_git_diff(&http_client, &review_payload.pull_request.diff_url).await?;
+
+        let diff_for_llm = format_diff_for_review(&git_diff);
+
+        let bot_request = REVIEW_PROMPT
+            .replace("{subject}", &review_payload.pull_request.title)
+            .replace("{comment}", &review_payload.comment.body)
+            .replace("{diff}", &diff_for_llm);
+
+        let chat_result = open_router_client.chat(&bot_request).await?;
+        let mut review_result = serde_json::from_str::<ReviewResult>(&chat_result.message)?;
+
+        review_result.cost = chat_result.cost;
+
+        gitea_api
+            .post_pull_request_review(
+                &review_result,
+                &review_payload.repository.full_name,
+                review_payload.pull_request.number,
+            )
+            .await?;
+
+        Ok(review_result)
+    }
+    .await;
+
+    let edit_msg = match bot_result {
+        Ok(bot_result) => review_result_to_markdown(&bot_result),
+        Err(e) => format!("Error while reviewing: {}", e),
+    };
+
+    gitea_api
+        .edit_comment(
+            &edit_msg,
+            &review_payload.repository.full_name,
+            new_comment.id,
+        )
+        .await?;
+
+    Ok(())
+}
+
+fn review_result_to_markdown(review_result: &ReviewResult) -> String {
+    if review_result.reviews.is_empty() {
+        return String::from("No issues found. ✅");
+    }
+
+    let mut md = String::from("## Review Feedback\n\n");
+
+    md.push_str(&format!(
+        "### {} issues found.\n\n",
+        review_result.reviews.len()
+    ));
+
+    if !review_result.comment.is_empty() {
+        md.push_str("\n---\n\n");
+        md.push_str("### Summary\n\n");
+        md.push_str(&review_result.comment);
+        md.push('\n');
+    }
+
+    if let Some(cost) = review_result.cost {
+        md.push_str("\n---\n\n");
+        md.push_str(&format!("### Cost: ${}", cost));
+        md.push('\n');
+    }
+
+    md
+}
+
+async fn download_git_diff(http_client: &reqwest::Client, url: &str) -> anyhow::Result<String> {
+    let response = http_client.get(url).send().await?;
+    let stream = response.bytes_stream().map_err(std::io::Error::other);
+
+    let mut buf = Vec::with_capacity(MAX_DIFF_SIZE);
+    StreamReader::new(stream)
+        .take((MAX_DIFF_SIZE + 1) as u64)
+        .read_to_end(&mut buf)
+        .await?;
+
+    if buf.len() > MAX_DIFF_SIZE {
+        anyhow::bail!("Git diff exceeds the maximum allowed size of 1 Mo");
+    }
+
+    Ok(String::from_utf8_lossy(&buf).into_owned())
+}
+
+fn format_diff_for_review(git_diff: &str) -> String {
+    let mut output = String::new();
+    let mut current_file: Option<&str> = None;
+    let mut new_line: u64 = 0;
+
+    for line in git_diff.lines() {
+        if let Some(rest) = line.strip_prefix("diff --git a/") {
+            if let Some(end) = rest.find(' ') {
+                current_file = Some(&rest[..end]);
+            }
+            new_line = 0;
+            continue;
+        }
+
+        if line.starts_with("---") || line.starts_with("+++") {
+            continue;
+        }
+
+        if line.starts_with("@@") && line.contains('+') {
+            if let Some(start) = parse_hunk_new_start(line) {
+                new_line = start;
+            }
+            continue;
+        }
+
+        let Some(filename) = current_file else {
+            continue;
+        };
+
+        if line.starts_with(' ') {
+            new_line += 1;
+            continue;
+        }
+
+        if let Some(code) = line.strip_prefix('+') {
+            use std::fmt::Write;
+            let _ = writeln!(output, "{filename}:{new_line}:{code}");
+            new_line += 1;
+        }
+    }
+
+    output
+}
+
+fn parse_hunk_new_start(hunk_header: &str) -> Option<u64> {
+    let plus_part = hunk_header.split('+').nth(1)?;
+    let num_str = plus_part.split(|c: char| !c.is_ascii_digit()).next()?;
+    num_str.parse::<u64>().ok()
+}
+
+#[cfg(test)]
+#[test]
+fn test_format_diff_for_review() {
+    let diff = concat!(
+        "diff --git a/src/foo.rs b/src/foo.rs\n",
+        "--- a/src/foo.rs\n",
+        "+++ b/src/foo.rs\n",
+        "@@ -1,3 +1,6 @@\n",
+        " fn main() {\n",
+        "+    let x = 1;\n",
+        "     println!(\"hello\");\n",
+        "+    let y = 2;\n",
+        "+    let z = 3;\n",
+        " }\n",
+        "diff --git a/src/bar.rs b/src/bar.rs\n",
+        "--- a/src/bar.rs\n",
+        "+++ b/src/bar.rs\n",
+        "@@ -10,4 +10,6 @@\n",
+        " old context\n",
+        "+    let a = 10;\n",
+        " more context\n",
+        "+    let b = 20;\n",
+    );
+
+    let result = format_diff_for_review(diff);
+    let expected = concat!(
+        "src/foo.rs:2:    let x = 1;\n",
+        "src/foo.rs:4:    let y = 2;\n",
+        "src/foo.rs:5:    let z = 3;\n",
+        "src/bar.rs:11:    let a = 10;\n",
+        "src/bar.rs:13:    let b = 20;\n",
+    );
+
+    assert_eq!(result, expected);
+}

src/consts.rs

@@ -1,3 +1,44 @@
 pub const GITEA_SIG_HEADER_NAME: &str = "x-gitea-signature";
 pub const GITEA_EVENT_TYPE_HEADER_NAME: &str = "x-gitea-event-type";
+
 pub const MAX_WEBHOOK_BODY_SIZE: usize = 1024 * 1024; // 1 MiB
+pub const MAX_DIFF_SIZE: usize = 1024 * 1024; // 1 MiB
+
+pub const BOT_PROCESS_MSG: &str = "
+    Review in progress with the model \"{model}\"...
+";
+
+pub const REVIEW_PROMPT: &str = "
+    You are a senior software engineer reviewing code changes.
+
+    Check good practices and code quality.
+
+    This is the pull request subject: \"{subject}\"
+
+    This is the user comment: \"{comment}\"
+
+    The code changes (only added lines, with line numbers):
+
+    {diff}
+
+    Please review the code changes and provide feedback.
+
+    IMPORTANT: the `line` field must be the line number shown before each line.
+    The provided code has the format: `filename:line:code`
+
+    Return your feedback, in french, with only this json format, reviews must contain each review
+    All fields are mandatory.
+    (filename field must contain the full path with extension) and comment must contain a final summary:
+
+    {
+        \"reviews\": [
+            {
+                \"filename\": \"\",
+                \"line\": ,
+                \"code\": \"\",
+                \"message\": \"\"
+            }
+        ],
+        \"comment\": \"\"
+    }
+";

src/env.rs

@@ -6,7 +6,12 @@ pub struct EnvConfig {
     pub http_port: u16,
     pub webhook_secret: String,
     pub open_router_api_key: String,
+    pub open_router_model: String,
+    pub open_router_timeout: u64,
     pub bot_name: String,
+    pub gitea_url: String,
+    pub gitea_token: String,
+    pub gitea_timeout: u64,
 }
 
 pub fn load_config() -> anyhow::Result<EnvConfig> {
@@ -16,12 +21,22 @@ pub fn load_config() -> anyhow::Result<EnvConfig> {
     let bot_name = try_get_env("BOT_NAME")?;
     let webhook_secret = try_get_env("WEBHOOK_SIG_HEADER_SECRET")?;
     let open_router_api_key = try_get_env("OPEN_ROUTER_API_KEY")?;
+    let open_router_model = try_get_env("OPEN_ROUTER_MODEL")?;
+    let open_router_timeout = try_get_env("OPEN_ROUTER_TIMEOUT")?.parse()?;
+    let gitea_url = try_get_env("GITEA_URL")?;
+    let gitea_token = try_get_env("GITEA_TOKEN")?;
+    let gitea_timeout = try_get_env("GITEA_TIMEOUT")?.parse()?;
 
     Ok(EnvConfig {
         http_port,
         webhook_secret,
         bot_name,
         open_router_api_key,
+        open_router_model,
+        open_router_timeout,
+        gitea_url,
+        gitea_token,
+        gitea_timeout,
     })
 }
 

src/gitea.rs

@@ -1,7 +1,135 @@
-use serde::Deserialize;
-use serde_json::Value;
+use std::time::Duration;
 
-use crate::errors::AppError;
+use serde::Deserialize;
+use serde_json::{Value, json};
+
+use crate::{
+    bot::{ReviewItem, ReviewResult},
+    errors::AppError,
+};
+
+pub struct GiteaAPI {
+    base_url: String,
+    client: reqwest::Client,
+}
+
+impl GiteaAPI {
+    pub fn new(base_url: &str, token: &str, timeout: u64) -> anyhow::Result<Self> {
+        let mut default_headers = reqwest::header::HeaderMap::new();
+        default_headers.insert(
+            reqwest::header::HeaderName::from_static("authorization"),
+            reqwest::header::HeaderValue::from_str(&format!("Bearer {}", token))?,
+        );
+
+        Ok(Self {
+            base_url: String::from(base_url),
+            client: reqwest::Client::builder()
+                .timeout(Duration::from_secs(timeout))
+                .default_headers(default_headers)
+                .build()?,
+        })
+    }
+
+    pub async fn comment(
+        &self,
+        body: &str,
+        full_name: &str,
+        index: u64,
+    ) -> anyhow::Result<Comment> {
+        let url = format!(
+            "{}/api/v1/repos/{}/issues/{}/comments",
+            self.base_url, full_name, index
+        );
+
+        let res = self
+            .client
+            .post(url)
+            .json(&json!({
+                "body": body
+            }))
+            .send()
+            .await?;
+
+        if !res.status().is_success() {
+            return Err(anyhow::anyhow!("Failed to comment: {}", res.status()));
+        }
+
+        res.json::<Comment>().await.map_err(anyhow::Error::from)
+    }
+
+    pub async fn edit_comment(
+        &self,
+        body: &str,
+        full_name: &str,
+        comment_id: u64,
+    ) -> anyhow::Result<()> {
+        let url = format!(
+            "{}/api/v1/repos/{}/issues/comments/{}",
+            self.base_url, full_name, comment_id
+        );
+
+        let res = self
+            .client
+            .patch(url)
+            .json(&json!({
+                "body": body
+            }))
+            .send()
+            .await?;
+
+        if !res.status().is_success() {
+            return Err(anyhow::anyhow!("Failed to comment: {}", res.status()));
+        }
+
+        Ok(())
+    }
+
+    pub async fn post_pull_request_review(
+        &self,
+        review_result: &ReviewResult,
+        full_name: &str,
+        index: u64,
+    ) -> anyhow::Result<()> {
+        let url = format!(
+            "{}/api/v1/repos/{}/pulls/{}/reviews",
+            self.base_url, full_name, index
+        );
+
+        let comments = &&review_result
+            .reviews
+            .iter()
+            .filter(|r| r.line.is_some())
+            .map(|r| {
+                let path = r.filename.clone();
+                let line = r.line.unwrap_or(0);
+                let body = r.message.clone();
+
+                json!({
+                    "path": path,
+                    "new_position": line,
+                    "body": body
+                })
+            })
+            .collect::<Vec<_>>();
+
+        let res = self
+            .client
+            .post(url)
+            .json(&json!({
+                "event": "COMMENT",
+                "body": review_result.comment,
+                "comments": comments
+            }))
+            .send()
+            .await?;
+
+        if !res.status().is_success() {
+            return Err(anyhow::anyhow!("Failed to post review: {}", res.status()));
+        }
+
+        Ok(())
+    }
+}
 
 #[derive(Debug)]
 pub enum WebhookType {
@@ -12,6 +140,7 @@ pub enum WebhookType {
 pub struct ReviewPayload {
     pub action: String,
     pub pull_request: PullRequest,
+    pub repository: Repository,
     pub comment: Comment,
 }
 
@@ -19,6 +148,8 @@ pub struct ReviewPayload {
 pub struct PullRequest {
     pub id: u64,
     pub diff_url: String,
+    pub number: u64,
+    pub title: String,
 }
 
 #[derive(Deserialize, Debug)]
@@ -33,6 +164,11 @@ pub struct User {
     pub id: u64,
 }
 
+#[derive(Deserialize, Debug)]
+pub struct Repository {
+    pub full_name: String,
+}
+
 impl WebhookType {
     pub fn from_event(event: &str, bot_name: &str, json: Value) -> Result<Self, AppError> {
         let wb = match event {

src/main.rs

@@ -1,25 +1,25 @@
-use std::sync::Arc;
-
-use tokio::sync::Mutex;
-
-use crate::{bot::Bot, state::AppState};
+use crate::{bot::Bot, gitea::WebhookType, state::AppState};
 
 mod api;
 mod bot;
+mod bot_actions;
 mod consts;
 mod env;
 mod errors;
 mod gitea;
+mod open_router;
 mod state;
 
 #[tokio::main]
 async fn main() -> anyhow::Result<()> {
     let config = env::load_config()?;
+    let bot = Bot::new(config.clone())?;
 
-    let app_state = AppState {
-        bot: Arc::new(Mutex::new(Bot::new(config.clone()))),
-        config: config,
-    };
+    let (tx, rx) = tokio::sync::mpsc::channel::<WebhookType>(1);
 
-    api::start(app_state).await
+    let app_state = AppState { bot_tx: tx, config };
+
+    tokio::try_join!(bot.start(rx), api::start(app_state))?;
+
+    Ok(())
 }

src/open_router.rs

@@ -0,0 +1,47 @@
+use std::time::Duration;
+
+use openrouter_rs::{Message, api::chat::ChatCompletionRequest};
+
+pub struct ChatResult {
+    pub message: String,
+    pub cost: Option<f64>,
+}
+
+pub struct OpenRouterClient {
+    client: openrouter_rs::OpenRouterClient,
+    model: String,
+}
+
+impl OpenRouterClient {
+    pub fn new(token: &str, model: &str, timeout: u64) -> anyhow::Result<Self> {
+        Ok(Self {
+            client: openrouter_rs::OpenRouterClient::builder()
+                .api_key(token)
+                .http_client(
+                    reqwest::Client::builder()
+                        .timeout(Duration::from_secs(timeout))
+                        .build()?,
+                )
+                .build()?,
+            model: String::from(model),
+        })
+    }
+
+    pub async fn chat(&self, msg: &str) -> anyhow::Result<ChatResult> {
+        let request = ChatCompletionRequest::builder()
+            .model(&self.model)
+            .enable_reasoning()
+            .messages(vec![Message::new(openrouter_rs::types::Role::User, msg)])
+            .build()?;
+
+        let response = self.client.chat().create(&request).await?;
+
+        Ok(ChatResult {
+            message: response.choices[0]
+                .content()
+                .map(|msg| String::from(msg))
+                .ok_or(anyhow::anyhow!("No content"))?,
+            cost: response.usage.and_then(|u| u.cost),
+        })
+    }
+}

src/state.rs

@@ -1,10 +1,7 @@
-use std::sync::Arc;
-use tokio::sync::Mutex;
-
-use crate::{bot::Bot, env::EnvConfig};
+use crate::{env::EnvConfig, gitea::WebhookType};
 
 #[derive(Clone)]
 pub struct AppState {
-    pub bot: Arc<Mutex<Bot>>,
+    pub bot_tx: tokio::sync::mpsc::Sender<WebhookType>,
     pub config: EnvConfig,
 }