image_exif: manual date_taken override (set/clear endpoints)

Add `POST /image/exif/date` and `POST /image/exif/date/clear` so an
operator can correct a row whose canonical-date waterfall landed on the
wrong value (camera clock reset, fs_time fallback for a copied-from-
backup file, etc). New `original_date_taken` / `original_date_taken_source`
columns snapshot the prior value on first override so revert is lossless.

The waterfall source set is now `'exif' | 'exiftool' | 'filename' | 'fs_time' | 'manual'`.
The existing `idx_image_exif_date_backfill` partial index already filters
to `date_taken IS NULL OR date_taken_source = 'fs_time'`, so manual rows
are naturally excluded from the per-tick drain — no index change needed.

`ExifMetadata` now exposes `date_taken_source` + originals so a UI can
render "manually set; was X via filename".

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/main.rs

@@ -41,7 +41,7 @@ use urlencoding::decode;
 use crate::ai::InsightGenerator;
 use crate::auth::login;
 use crate::data::*;
-use crate::database::models::InsertImageExif;
+use crate::database::models::{ImageExif, InsertImageExif};
 use crate::database::*;
 use crate::files::{
     RealFileSystem, RefreshThumbnailsMessage, is_image_or_video, is_valid_full_path, move_file,
@@ -593,6 +593,154 @@ async fn set_image_gps(
     }
 }
 
+/// Body for `POST /image/exif/date` — operator-driven date_taken override.
+/// `date_taken` is unix seconds (matches `image_exif.date_taken`'s convention
+/// — naive local reinterpreted as UTC, not real UTC; the Apollo client passes
+/// through the same value the photo carousel rendered before edit).
+#[derive(serde::Deserialize)]
+struct SetDateRequest {
+    path: String,
+    library: Option<String>,
+    date_taken: i64,
+}
+
+/// Body for `POST /image/exif/date/clear` — revert a manual override and
+/// restore the resolver-derived `(date_taken, date_taken_source)` pair from
+/// the snapshot.
+#[derive(serde::Deserialize)]
+struct ClearDateRequest {
+    path: String,
+    library: Option<String>,
+}
+
+/// Build a `MetadataResponse` for the date endpoints. Mirrors
+/// `get_file_metadata`'s shape so the client gets a single source of truth
+/// after every mutation. Filesystem metadata is best-effort: if the file is
+/// on a stale mount or moved, the DB-side override still succeeds and the
+/// response carries `created=None, modified=None, size=0`. The DB row's
+/// updated EXIF is what matters here.
+fn build_metadata_response_for_date_mutation(
+    library: &libraries::Library,
+    rel_path: &str,
+    exif: ImageExif,
+) -> MetadataResponse {
+    let full_path = is_valid_full_path(&library.root_path, &rel_path.to_string(), false);
+    let fs_meta = full_path
+        .as_ref()
+        .filter(|p| p.exists())
+        .and_then(|p| std::fs::metadata(p).ok());
+    let mut response: MetadataResponse = match fs_meta {
+        Some(m) => m.into(),
+        None => MetadataResponse {
+            created: None,
+            modified: None,
+            size: 0,
+            exif: None,
+            filename_date: None,
+            library_id: None,
+            library_name: None,
+        },
+    };
+    response.exif = Some(exif.into());
+    response.library_id = Some(library.id);
+    response.library_name = Some(library.name.clone());
+    response.filename_date =
+        memories::extract_date_from_filename(rel_path).map(|dt| dt.timestamp());
+    response
+}
+
+#[post("/image/exif/date")]
+async fn set_image_date(
+    _: Claims,
+    request: HttpRequest,
+    body: web::Json<SetDateRequest>,
+    app_state: Data<AppState>,
+    exif_dao: Data<Mutex<Box<dyn ExifDao>>>,
+) -> impl Responder {
+    let tracer = global_tracer();
+    let context = extract_context_from_request(&request);
+    let mut span = tracer.start_with_context("set_image_date", &context);
+    let span_context =
+        opentelemetry::Context::new().with_remote_span_context(span.span_context().clone());
+
+    let library = libraries::resolve_library_param(&app_state, body.library.as_deref())
+        .ok()
+        .flatten()
+        .unwrap_or_else(|| app_state.primary_library());
+
+    // Path normalization matches set_image_gps so a Windows-import client
+    // doesn't end up with a backslash variant that misses the row.
+    let normalized_path = body.path.replace('\\', "/");
+
+    let updated = {
+        let mut dao = exif_dao.lock().expect("Unable to lock ExifDao");
+        dao.set_manual_date_taken(&span_context, library.id, &normalized_path, body.date_taken)
+    };
+
+    match updated {
+        Ok(row) => {
+            span.set_status(Status::Ok);
+            HttpResponse::Ok().json(build_metadata_response_for_date_mutation(
+                &library,
+                &normalized_path,
+                row,
+            ))
+        }
+        Err(e) => {
+            let msg = format!("set_manual_date_taken failed: {:?}", e);
+            error!("{}", msg);
+            span.set_status(Status::error(msg.clone()));
+            // Likely "row not found" — the file isn't indexed under this
+            // (library, path). 404 lets the client distinguish from a 5xx.
+            HttpResponse::NotFound().body(msg)
+        }
+    }
+}
+
+#[post("/image/exif/date/clear")]
+async fn clear_image_date(
+    _: Claims,
+    request: HttpRequest,
+    body: web::Json<ClearDateRequest>,
+    app_state: Data<AppState>,
+    exif_dao: Data<Mutex<Box<dyn ExifDao>>>,
+) -> impl Responder {
+    let tracer = global_tracer();
+    let context = extract_context_from_request(&request);
+    let mut span = tracer.start_with_context("clear_image_date", &context);
+    let span_context =
+        opentelemetry::Context::new().with_remote_span_context(span.span_context().clone());
+
+    let library = libraries::resolve_library_param(&app_state, body.library.as_deref())
+        .ok()
+        .flatten()
+        .unwrap_or_else(|| app_state.primary_library());
+
+    let normalized_path = body.path.replace('\\', "/");
+
+    let updated = {
+        let mut dao = exif_dao.lock().expect("Unable to lock ExifDao");
+        dao.clear_manual_date_taken(&span_context, library.id, &normalized_path)
+    };
+
+    match updated {
+        Ok(row) => {
+            span.set_status(Status::Ok);
+            HttpResponse::Ok().json(build_metadata_response_for_date_mutation(
+                &library,
+                &normalized_path,
+                row,
+            ))
+        }
+        Err(e) => {
+            let msg = format!("clear_manual_date_taken failed: {:?}", e);
+            error!("{}", msg);
+            span.set_status(Status::error(msg.clone()));
+            HttpResponse::NotFound().body(msg)
+        }
+    }
+}
+
 #[derive(serde::Deserialize)]
 struct UploadQuery {
     library: Option<String>,
@@ -1697,6 +1845,8 @@ fn main() -> std::io::Result<()> {
                 .service(delete_favorite)
                 .service(get_file_metadata)
                 .service(set_image_gps)
+                .service(set_image_date)
+                .service(clear_image_date)
                 .service(memories::list_memories)
                 .service(ai::generate_insight_handler)
                 .service(ai::generate_agentic_insight_handler)