feat: Add case closing and document viewing routes

Adds API endpoints for closing a case, which triggers an analysis job,
and for viewing the generated document.

This also includes:
- New `AppError` variants: `Conflict` and `ServiceUnavailable`.
- Helper functions for file handling, date parsing, and document
  searching.
- Unit tests for helper functions.

server/src/error.rs

@@ -6,6 +6,11 @@ pub enum AppError {
     Unauthorized,
     BadRequest(String),
     NotFound(String),
+    /// 409 — request is valid but conflicts with current state (e.g. an
+    /// analysis is already running for this case).
+    Conflict(String),
+    /// 503 — the feature is unavailable right now (e.g. no LLM configured).
+    ServiceUnavailable(String),
     Internal(String),
     /// 302 redirect. Used by web auth to send unauthenticated users to login.
     Redirect(String),
@@ -25,6 +30,8 @@ impl IntoResponse for AppError {
             Self::Unauthorized => (StatusCode::UNAUTHORIZED, "Unauthorized".to_owned()),
             Self::BadRequest(msg) => (StatusCode::BAD_REQUEST, msg.clone()),
             Self::NotFound(msg) => (StatusCode::NOT_FOUND, msg.clone()),
+            Self::Conflict(msg) => (StatusCode::CONFLICT, msg.clone()),
+            Self::ServiceUnavailable(msg) => (StatusCode::SERVICE_UNAVAILABLE, msg.clone()),
             Self::Internal(msg) => (StatusCode::INTERNAL_SERVER_ERROR, msg.clone()),
             Self::Redirect(_) => unreachable!(),
         };

server/src/routes/case_actions.rs

@@ -0,0 +1,294 @@
+use std::path::{Path, PathBuf};
+use std::sync::Arc;
+use std::time::SystemTime;
+
+use axum::extract::{Path as AxumPath, State};
+use axum::response::{Html, Redirect};
+use time::format_description::well_known::Rfc3339;
+use time::OffsetDateTime;
+use tokio::io::AsyncWriteExt;
+use tracing::{info, warn};
+
+use crate::analyze::{AnalysisInput, AnalyzeJob, AnalyzeSender, RecordingInput};
+use crate::auth::AuthenticatedWebUser;
+use crate::config::Config;
+use crate::error::AppError;
+use crate::routes::user_web::locate_case;
+
+/// POST /web/cases/{case_id}/close
+///
+/// Persist an `analysis_input_v1.json` for the case and enqueue an analyze
+/// job. Redirects back to the case detail page where the UI will show
+/// "wird analysiert …" until the worker writes `document_v1.md`.
+pub async fn handle_close_case(
+    user: AuthenticatedWebUser,
+    State(config): State<Arc<Config>>,
+    State(analyze_tx): State<AnalyzeSender>,
+    AxumPath(case_id): AxumPath<String>,
+) -> Result<Redirect, AppError> {
+    uuid::Uuid::parse_str(&case_id)
+        .map_err(|_| AppError::BadRequest("Invalid case_id".into()))?;
+
+    // Server-side guard mirroring the UI gate: no close without a configured LLM.
+    if !config.llm_configured() {
+        return Err(AppError::ServiceUnavailable(
+            "LLM-Analyse nicht konfiguriert".into(),
+        ));
+    }
+
+    // Close only acts on cases in open/. A case in done/ is already finalized.
+    let user_root = config.data_path.join(&user.slug);
+    let case_dir = user_root.join("open").join(&case_id);
+    if !tokio::fs::try_exists(&case_dir).await.unwrap_or(false) {
+        warn!(slug = %user.slug, case_id = %case_id, "close: case not found in open/");
+        return Err(AppError::NotFound("Case not found".into()));
+    }
+
+    let input_path = case_dir.join("analysis_input_v1.json");
+    if tokio::fs::try_exists(&input_path).await.unwrap_or(false) {
+        return Err(AppError::Conflict(
+            "Analyse läuft bereits für diesen Fall".into(),
+        ));
+    }
+
+    // Collect all active `.m4a` recordings and the transcripts next to them.
+    // `.m4a.failed` entries are deliberately skipped: they block nothing and
+    // carry no transcript. The doctor handles them manually.
+    let m4as = collect_m4as(&case_dir).await?;
+    if m4as.is_empty() {
+        return Err(AppError::BadRequest("Keine Aufnahmen im Fall".into()));
+    }
+
+    let mut recordings: Vec<RecordingInput> = Vec::new();
+    let mut last_mtime: SystemTime = SystemTime::UNIX_EPOCH;
+    for (m4a_path, mtime) in &m4as {
+        if *mtime > last_mtime {
+            last_mtime = *mtime;
+        }
+
+        let transcript_path = m4a_path.with_extension("transcript.txt");
+        let text = tokio::fs::read_to_string(&transcript_path)
+            .await
+            .map_err(|_| {
+                AppError::BadRequest("Nicht alle Aufnahmen sind transkribiert".into())
+            })?;
+
+        if text.trim().is_empty() {
+            // Skip blank transcripts from the LLM input — they add noise
+            // without signal. The `.m4a` still contributes to `last_mtime`.
+            continue;
+        }
+
+        let stem = m4a_path.file_stem().and_then(|s| s.to_str()).unwrap_or("");
+        recordings.push(RecordingInput {
+            recorded_at: filename_stem_to_recorded_at(stem),
+            text,
+        });
+    }
+
+    if recordings.is_empty() {
+        return Err(AppError::BadRequest(
+            "Keine nicht-leeren Transkripte im Fall".into(),
+        ));
+    }
+
+    let last_recording_mtime = OffsetDateTime::from(last_mtime)
+        .format(&Rfc3339)
+        .map_err(|e| AppError::Internal(format!("format mtime: {e}")))?;
+
+    let input = AnalysisInput {
+        version: 1,
+        last_recording_mtime,
+        recordings,
+    };
+
+    write_input_create_new(&input_path, &input).await?;
+
+    // Unbounded send: only fails if the worker has gone away (programmer error
+    // or shutdown race). Log but don't fail the request — the file is already
+    // on disk and recovery will pick it up on next startup.
+    if analyze_tx
+        .send(AnalyzeJob {
+            case_dir: case_dir.clone(),
+            version: 1,
+        })
+        .is_err()
+    {
+        warn!(case_id = %case_id, "analyze send failed (worker gone)");
+    }
+
+    info!(
+        slug = %user.slug,
+        case_id = %case_id,
+        recordings = input.recordings.len(),
+        "close requested; analysis enqueued"
+    );
+
+    Ok(Redirect::to(&format!("/web/cases/{case_id}")))
+}
+
+/// GET /web/cases/{case_id}/document
+///
+/// Render the latest `document_v{N}.md` for the case. The handler scans the
+/// case directory and picks the highest N — no symlink, no separate pointer.
+pub async fn handle_document_view(
+    user: AuthenticatedWebUser,
+    State(config): State<Arc<Config>>,
+    AxumPath(case_id): AxumPath<String>,
+) -> Result<Html<String>, AppError> {
+    uuid::Uuid::parse_str(&case_id)
+        .map_err(|_| AppError::BadRequest("Invalid case_id".into()))?;
+
+    let user_root = config.data_path.join(&user.slug);
+    let (case_dir, _status) = match locate_case(&user_root, &case_id).await {
+        Some(v) => v,
+        None => {
+            warn!(slug = %user.slug, case_id = %case_id, "document view: case not found");
+            return Err(AppError::NotFound("Case not found".into()));
+        }
+    };
+
+    let (version, content) = find_latest_document(&case_dir)
+        .await
+        .ok_or_else(|| AppError::NotFound("Noch kein Dokument erzeugt".into()))?;
+
+    // Minimal inline HTML for step 4; replaced with a proper template in step 7.
+    let escaped = content
+        .replace('&', "&amp;")
+        .replace('<', "&lt;")
+        .replace('>', "&gt;");
+    Ok(Html(format!(
+        "<!doctype html><html><head><meta charset=\"utf-8\"><title>Dokument v{version}</title></head><body><pre>{escaped}</pre><p><a href=\"/web/cases/{case_id}\">Zurück</a></p></body></html>"
+    )))
+}
+
+/// Return `(path, mtime)` for every `.m4a` file directly under `case_dir`,
+/// sorted by filename (chronological, since filenames are UTC timestamps).
+/// `.m4a.failed` entries are skipped.
+async fn collect_m4as(case_dir: &Path) -> Result<Vec<(PathBuf, SystemTime)>, AppError> {
+    let mut out = Vec::new();
+    let mut entries = tokio::fs::read_dir(case_dir).await?;
+    while let Some(entry) = entries.next_entry().await? {
+        let filename = match entry.file_name().into_string() {
+            Ok(s) => s,
+            Err(_) => continue,
+        };
+        if !filename.ends_with(".m4a") {
+            continue;
+        }
+        let path = entry.path();
+        let mtime = entry.metadata().await?.modified()?;
+        out.push((path, mtime));
+    }
+    out.sort_by(|a, b| a.0.cmp(&b.0));
+    Ok(out)
+}
+
+/// Serialize `input` and write it to `path` using `create_new` to atomically
+/// reserve the destination. Returns `Conflict` if another close already won
+/// the race.
+///
+/// Trade-off: if the process crashes between `open` and `write_all`/`sync_all`,
+/// a zero-byte or partially-written JSON remains. The worker will fail to
+/// deserialize it and log an error — manual cleanup required. For MVP the
+/// simpler check-and-create is acceptable.
+async fn write_input_create_new(
+    path: &Path,
+    input: &AnalysisInput,
+) -> Result<(), AppError> {
+    let bytes = serde_json::to_vec_pretty(input)
+        .map_err(|e| AppError::Internal(format!("serialize input: {e}")))?;
+
+    let mut f = match tokio::fs::OpenOptions::new()
+        .write(true)
+        .create_new(true)
+        .open(path)
+        .await
+    {
+        Ok(f) => f,
+        Err(e) if e.kind() == std::io::ErrorKind::AlreadyExists => {
+            return Err(AppError::Conflict(
+                "Analyse läuft bereits für diesen Fall".into(),
+            ));
+        }
+        Err(e) => return Err(AppError::Internal(e.to_string())),
+    };
+    f.write_all(&bytes).await?;
+    f.sync_all().await?;
+    Ok(())
+}
+
+/// Reverse the filesystem-safe timestamp mapping applied in `upload.rs`:
+/// `:` in the time portion was replaced with `-`. Split at `T`, undo hyphens
+/// only in the time part to avoid touching date hyphens.
+fn filename_stem_to_recorded_at(stem: &str) -> String {
+    match stem.split_once('T') {
+        Some((date, time)) => format!("{}T{}", date, time.replace('-', ":")),
+        None => stem.to_string(),
+    }
+}
+
+/// Scan `case_dir` for `document_v{N}.md`, pick the highest N, return its
+/// content together with N. Returns `None` if no document exists.
+async fn find_latest_document(case_dir: &Path) -> Option<(u32, String)> {
+    let mut highest: Option<u32> = None;
+    let mut entries = tokio::fs::read_dir(case_dir).await.ok()?;
+    while let Ok(Some(entry)) = entries.next_entry().await {
+        let name = entry.file_name();
+        let Some(name_str) = name.to_str() else { continue };
+        let Some(version) = parse_document_version(name_str) else {
+            continue;
+        };
+        highest = match highest {
+            Some(h) if h >= version => Some(h),
+            _ => Some(version),
+        };
+    }
+    let v = highest?;
+    let content = tokio::fs::read_to_string(case_dir.join(format!("document_v{v}.md")))
+        .await
+        .ok()?;
+    Some((v, content))
+}
+
+fn parse_document_version(filename: &str) -> Option<u32> {
+    let rest = filename.strip_prefix("document_v")?;
+    let num = rest.strip_suffix(".md")?;
+    if num.is_empty() || (num.starts_with('0') && num.len() > 1) {
+        return None;
+    }
+    num.parse::<u32>().ok()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn filename_stem_roundtrip() {
+        assert_eq!(
+            filename_stem_to_recorded_at("2026-04-15T10-32-00Z"),
+            "2026-04-15T10:32:00Z"
+        );
+        // Date-only hyphens are preserved.
+        assert_eq!(
+            filename_stem_to_recorded_at("2026-04-15T10-32-00.123Z"),
+            "2026-04-15T10:32:00.123Z"
+        );
+    }
+
+    #[test]
+    fn parses_valid_document_names() {
+        assert_eq!(parse_document_version("document_v1.md"), Some(1));
+        assert_eq!(parse_document_version("document_v42.md"), Some(42));
+    }
+
+    #[test]
+    fn rejects_invalid_document_names() {
+        assert_eq!(parse_document_version("document_v01.md"), None);
+        assert_eq!(parse_document_version("document_v.md"), None);
+        assert_eq!(parse_document_version("document_vx.md"), None);
+        assert_eq!(parse_document_version("analysis_input_v1.json"), None);
+        assert_eq!(parse_document_version(""), None);
+    }
+}

server/src/routes/mod.rs

@@ -1,9 +1,10 @@
+mod case_actions;
 mod debug;
 mod health;
 mod login;
 mod upload;
+pub(crate) mod user_web;
 pub(crate) mod web;
-mod user_web;
 
 use axum::routing::{get, post};
 use axum::Router;
@@ -19,6 +20,14 @@ pub fn api_router() -> Router<AppState> {
         .route("/web/logout", post(login::handle_logout))
         .route("/web/cases", get(user_web::handle_my_cases))
         .route("/web/cases/{case_id}", get(user_web::handle_case_detail))
+        .route(
+            "/web/cases/{case_id}/close",
+            post(case_actions::handle_close_case),
+        )
+        .route(
+            "/web/cases/{case_id}/document",
+            get(case_actions::handle_document_view),
+        )
         .route("/web/", get(web::handle_case_list))
         .route(
             "/web/audio/{user}/{case_id}/{filename}",

server/src/routes/user_web.rs

@@ -97,7 +97,7 @@ pub async fn handle_case_detail(
 
 /// Locate a case directory under `<user_root>/{open|done}/<case_id>`.
 /// Returns the path and the status bucket it was found in.
-async fn locate_case(user_root: &Path, case_id: &str) -> Option<(std::path::PathBuf, String)> {
+pub(crate) async fn locate_case(user_root: &Path, case_id: &str) -> Option<(std::path::PathBuf, String)> {
     for status in ["open", "done"] {
         let p = user_root.join(status).join(case_id);
         if tokio::fs::try_exists(&p).await.unwrap_or(false) {