weave_content/

verifier.rs

use std::time::Duration;

use crate::entity::{Entity, FieldValue};
use crate::parser::ParseError;
use crate::relationship::Rel;

/// Maximum total URLs per verify run.
const MAX_URLS_PER_RUN: usize = 500;

/// Maximum redirect hops.
const MAX_REDIRECTS: usize = 5;

/// User-Agent header.
const USER_AGENT: &str = "weave-content/0.2 (+https://github.com/redberrythread/weave)";

/// Result of checking a single URL.
#[derive(Debug)]
pub struct UrlCheck {
    pub url: String,
    pub status: CheckStatus,
    pub detail: Option<String>,
    /// Whether this URL is a thumbnail (needs content-type check).
    pub is_thumbnail: bool,
}

/// Severity level of a URL check result.
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub enum CheckStatus {
    Ok,
    Warn,
    Error,
}

impl std::fmt::Display for CheckStatus {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::Ok => write!(f, "ok"),
            Self::Warn => write!(f, "warn"),
            Self::Error => write!(f, "error"),
        }
    }
}

/// Collected URL to verify with its source location.
#[derive(Debug, Clone)]
pub struct UrlEntry {
    url: String,
    is_thumbnail: bool,
}

impl UrlEntry {
    /// URL accessor.
    pub fn url(&self) -> &str {
        &self.url
    }

    /// Thumbnail flag accessor.
    pub fn is_thumbnail(&self) -> bool {
        self.is_thumbnail
    }
}

/// Collect all URLs from parsed case data for verification.
pub fn collect_urls(
    sources: &[String],
    entities: &[Entity],
    rels: &[Rel],
    errors: &mut Vec<ParseError>,
) -> Vec<UrlEntry> {
    let mut urls = Vec::new();

    // Front matter sources
    for url in sources {
        urls.push(UrlEntry {
            url: url.clone(),
            is_thumbnail: false,
        });
    }

    // Entity URLs and thumbnails
    for entity in entities {
        for (key, value) in &entity.fields {
            match key.as_str() {
                "thumbnail" | "thumbnail_source" => {
                    if let FieldValue::Single(url) = value
                        && !url.is_empty()
                    {
                        urls.push(UrlEntry {
                            url: url.clone(),
                            is_thumbnail: true,
                        });
                    }
                }
                "urls" => {
                    if let FieldValue::List(items) = value {
                        for url in items {
                            urls.push(UrlEntry {
                                url: url.clone(),
                                is_thumbnail: false,
                            });
                        }
                    }
                }
                _ => {}
            }
        }
    }

    // Relationship source URL overrides
    for rel in rels {
        for url in &rel.source_urls {
            urls.push(UrlEntry {
                url: url.clone(),
                is_thumbnail: false,
            });
        }
    }

    // Deduplicate by URL
    let mut seen = std::collections::HashSet::new();
    urls.retain(|entry| seen.insert(entry.url.clone()));

    // Boundary check
    if urls.len() > MAX_URLS_PER_RUN {
        errors.push(ParseError {
            line: 0,
            message: format!(
                "too many URLs to verify (max {MAX_URLS_PER_RUN}, got {})",
                urls.len()
            ),
        });
    }

    urls
}

/// Verify all collected URLs concurrently.
pub async fn verify_urls(
    urls: Vec<UrlEntry>,
    concurrency: usize,
    timeout_secs: u64,
) -> Vec<UrlCheck> {
    let client = reqwest::Client::builder()
        .user_agent(USER_AGENT)
        .redirect(reqwest::redirect::Policy::limited(MAX_REDIRECTS))
        .timeout(Duration::from_secs(timeout_secs))
        .build()
        .unwrap_or_else(|_| reqwest::Client::new());

    let semaphore = std::sync::Arc::new(tokio::sync::Semaphore::new(concurrency));
    let client = std::sync::Arc::new(client);

    let mut handles = Vec::new();

    for entry in urls {
        let sem = semaphore.clone();
        let cli = client.clone();
        handles.push(tokio::spawn(async move {
            let _permit = sem.acquire().await;
            check_url(&cli, &entry.url, entry.is_thumbnail).await
        }));
    }

    let mut results = Vec::new();
    for handle in handles {
        match handle.await {
            Ok(check) => results.push(check),
            Err(e) => results.push(UrlCheck {
                url: "unknown".into(),
                status: CheckStatus::Error,
                detail: Some(format!("task panicked: {e}")),
                is_thumbnail: false,
            }),
        }
    }

    results
}

async fn check_url(client: &reqwest::Client, url: &str, is_thumbnail: bool) -> UrlCheck {
    // Try HEAD first
    match client.head(url).send().await {
        Ok(resp) => {
            let status = resp.status();

            // If HEAD returns 405, try GET
            if status == reqwest::StatusCode::METHOD_NOT_ALLOWED {
                return check_url_get(client, url, is_thumbnail).await;
            }

            evaluate_response(url, status, resp.headers(), is_thumbnail)
        }
        Err(e) => {
            if e.is_timeout() {
                UrlCheck {
                    url: url.to_string(),
                    status: CheckStatus::Warn,
                    detail: Some("timeout".into()),
                    is_thumbnail,
                }
            } else {
                UrlCheck {
                    url: url.to_string(),
                    status: CheckStatus::Error,
                    detail: Some(format!("{e}")),
                    is_thumbnail,
                }
            }
        }
    }
}

async fn check_url_get(client: &reqwest::Client, url: &str, is_thumbnail: bool) -> UrlCheck {
    match client.get(url).send().await {
        Ok(resp) => evaluate_response(url, resp.status(), resp.headers(), is_thumbnail),
        Err(e) => {
            if e.is_timeout() {
                UrlCheck {
                    url: url.to_string(),
                    status: CheckStatus::Warn,
                    detail: Some("timeout".into()),
                    is_thumbnail,
                }
            } else {
                UrlCheck {
                    url: url.to_string(),
                    status: CheckStatus::Error,
                    detail: Some(format!("{e}")),
                    is_thumbnail,
                }
            }
        }
    }
}

fn evaluate_response(
    url: &str,
    status: reqwest::StatusCode,
    headers: &reqwest::header::HeaderMap,
    is_thumbnail: bool,
) -> UrlCheck {
    if status.is_success() {
        // Check thumbnail content-type
        if is_thumbnail && let Some(ct) = headers.get(reqwest::header::CONTENT_TYPE) {
            let ct_str = ct.to_str().unwrap_or("");
            if !ct_str.starts_with("image/") {
                return UrlCheck {
                    url: url.to_string(),
                    status: CheckStatus::Error,
                    detail: Some(format!("expected content-type image/*, got {ct_str}")),
                    is_thumbnail,
                };
            }
        }

        UrlCheck {
            url: url.to_string(),
            status: CheckStatus::Ok,
            detail: None,
            is_thumbnail,
        }
    } else if status.is_redirection() {
        // Redirect not followed (should be handled by client policy)
        UrlCheck {
            url: url.to_string(),
            status: CheckStatus::Warn,
            detail: Some(format!("HTTP {status}")),
            is_thumbnail,
        }
    } else {
        UrlCheck {
            url: url.to_string(),
            status: CheckStatus::Error,
            detail: Some(format!("HTTP {status}")),
            is_thumbnail,
        }
    }
}

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

    #[test]
    fn collect_urls_deduplicates() {
        let sources = vec!["https://a.com".into(), "https://b.com".into()];
        let entities = vec![Entity {
            name: "Test".into(),
            label: crate::entity::Label::Actor,
            fields: vec![(
                "urls".into(),
                FieldValue::List(vec!["https://a.com".into(), "https://c.com".into()]),
            )],
            id: None,
            line: 1,
        }];
        let mut errors = Vec::new();

        let urls = collect_urls(&sources, &entities, &[], &mut errors);
        assert!(errors.is_empty());
        // a.com deduplicated
        assert_eq!(urls.len(), 3);
    }

    #[test]
    fn collect_urls_includes_thumbnails() {
        let entities = vec![Entity {
            name: "Test".into(),
            label: crate::entity::Label::Actor,
            fields: vec![(
                "thumbnail".into(),
                FieldValue::Single("https://img.com/photo.jpg".into()),
            )],
            id: None,
            line: 1,
        }];
        let mut errors = Vec::new();

        let urls = collect_urls(&[], &entities, &[], &mut errors);
        assert_eq!(urls.len(), 1);
        assert!(urls[0].is_thumbnail);
    }

    #[test]
    fn collect_urls_includes_rel_sources() {
        let rels = vec![Rel {
            source_name: "A".into(),
            target_name: "B".into(),
            rel_type: "related_to".into(),
            source_urls: vec!["https://src.com".into()],
            fields: vec![],
            id: None,
            line: 1,
        }];
        let mut errors = Vec::new();

        let urls = collect_urls(&[], &[], &rels, &mut errors);
        assert_eq!(urls.len(), 1);
        assert!(!urls[0].is_thumbnail);
    }

    #[test]
    fn collect_urls_boundary() {
        let sources: Vec<String> = (0..501)
            .map(|i| format!("https://example.com/{i}"))
            .collect();
        let mut errors = Vec::new();

        collect_urls(&sources, &[], &[], &mut errors);
        assert!(errors.iter().any(|e| e.message.contains("too many URLs")));
    }

    #[test]
    fn evaluate_success() {
        let check = evaluate_response(
            "https://example.com",
            reqwest::StatusCode::OK,
            &reqwest::header::HeaderMap::new(),
            false,
        );
        assert_eq!(check.status, CheckStatus::Ok);
    }

    #[test]
    fn evaluate_not_found() {
        let check = evaluate_response(
            "https://example.com",
            reqwest::StatusCode::NOT_FOUND,
            &reqwest::header::HeaderMap::new(),
            false,
        );
        assert_eq!(check.status, CheckStatus::Error);
    }

    #[test]
    fn evaluate_thumbnail_wrong_content_type() {
        let mut headers = reqwest::header::HeaderMap::new();
        headers.insert(
            reqwest::header::CONTENT_TYPE,
            "text/html".parse().unwrap_or_else(|_| unreachable!()),
        );
        let check = evaluate_response(
            "https://example.com/img.jpg",
            reqwest::StatusCode::OK,
            &headers,
            true,
        );
        assert_eq!(check.status, CheckStatus::Error);
        assert!(check.detail.as_deref().unwrap_or("").contains("image/*"));
    }

    #[test]
    fn evaluate_thumbnail_correct_content_type() {
        let mut headers = reqwest::header::HeaderMap::new();
        headers.insert(
            reqwest::header::CONTENT_TYPE,
            "image/jpeg".parse().unwrap_or_else(|_| unreachable!()),
        );
        let check = evaluate_response(
            "https://example.com/img.jpg",
            reqwest::StatusCode::OK,
            &headers,
            true,
        );
        assert_eq!(check.status, CheckStatus::Ok);
    }

    #[tokio::test]
    async fn verify_urls_with_mock_server_ok() {
        let mut server = mockito::Server::new_async().await;
        let mock = server
            .mock("HEAD", "/page")
            .with_status(200)
            .create_async()
            .await;

        let urls = vec![UrlEntry {
            url: format!("{}/page", server.url()),
            is_thumbnail: false,
        }];

        let results = verify_urls(urls, 4, 5).await;
        assert_eq!(results.len(), 1);
        assert_eq!(results[0].status, CheckStatus::Ok);
        mock.assert_async().await;
    }

    #[tokio::test]
    async fn verify_urls_with_mock_server_404() {
        let mut server = mockito::Server::new_async().await;
        let mock = server
            .mock("HEAD", "/missing")
            .with_status(404)
            .create_async()
            .await;

        let urls = vec![UrlEntry {
            url: format!("{}/missing", server.url()),
            is_thumbnail: false,
        }];

        let results = verify_urls(urls, 4, 5).await;
        assert_eq!(results.len(), 1);
        assert_eq!(results[0].status, CheckStatus::Error);
        assert!(results[0].detail.as_deref().unwrap_or("").contains("404"));
        mock.assert_async().await;
    }

    #[tokio::test]
    async fn verify_urls_head_405_falls_back_to_get() {
        let mut server = mockito::Server::new_async().await;
        let head_mock = server
            .mock("HEAD", "/no-head")
            .with_status(405)
            .create_async()
            .await;
        let get_mock = server
            .mock("GET", "/no-head")
            .with_status(200)
            .create_async()
            .await;

        let urls = vec![UrlEntry {
            url: format!("{}/no-head", server.url()),
            is_thumbnail: false,
        }];

        let results = verify_urls(urls, 4, 5).await;
        assert_eq!(results.len(), 1);
        assert_eq!(results[0].status, CheckStatus::Ok);
        head_mock.assert_async().await;
        get_mock.assert_async().await;
    }

    #[tokio::test]
    async fn verify_urls_thumbnail_content_type_check() {
        let mut server = mockito::Server::new_async().await;
        let mock = server
            .mock("HEAD", "/img.jpg")
            .with_status(200)
            .with_header("content-type", "image/jpeg")
            .create_async()
            .await;

        let urls = vec![UrlEntry {
            url: format!("{}/img.jpg", server.url()),
            is_thumbnail: true,
        }];

        let results = verify_urls(urls, 4, 5).await;
        assert_eq!(results.len(), 1);
        assert_eq!(results[0].status, CheckStatus::Ok);
        mock.assert_async().await;
    }

    #[tokio::test]
    async fn verify_urls_thumbnail_wrong_content_type() {
        let mut server = mockito::Server::new_async().await;
        let mock = server
            .mock("HEAD", "/not-image")
            .with_status(200)
            .with_header("content-type", "text/html")
            .create_async()
            .await;

        let urls = vec![UrlEntry {
            url: format!("{}/not-image", server.url()),
            is_thumbnail: true,
        }];

        let results = verify_urls(urls, 4, 5).await;
        assert_eq!(results.len(), 1);
        assert_eq!(results[0].status, CheckStatus::Error);
        assert!(
            results[0]
                .detail
                .as_deref()
                .unwrap_or("")
                .contains("image/*")
        );
        mock.assert_async().await;
    }
}