insights-correlations (#22)

Reviewed-on: #22

crates/presentation/src/handlers/insights.rs

@@ -0,0 +1,95 @@
+use axum::{
+    Json,
+    extract::{Query, State},
+};
+
+use application::insights::get as get_insights_uc;
+use domain::{errors::DomainError, models::Insight};
+
+use crate::{errors::ApiError, extractors::AuthenticatedUser, state::AppState};
+use api_types::insights::{InsightDto, InsightsQueryParams, InsightsResponse};
+
+fn to_dto(insight: Insight) -> InsightDto {
+    match insight {
+        Insight::RatingLift {
+            genre,
+            genre_avg,
+            user_avg,
+            delta,
+            sample_count,
+        } => InsightDto::RatingLift {
+            genre,
+            genre_avg,
+            user_avg,
+            delta,
+            sample_count,
+        },
+        Insight::Seasonality {
+            genre,
+            month,
+            multiplier,
+            sample_count,
+        } => InsightDto::Seasonality {
+            genre,
+            month,
+            multiplier,
+            sample_count,
+        },
+        Insight::MediumTiming {
+            medium,
+            multiplier,
+            weekend_share,
+            baseline_share,
+            sample_count,
+        } => InsightDto::MediumTiming {
+            medium,
+            multiplier,
+            weekend_share,
+            baseline_share,
+            sample_count,
+        },
+        Insight::Rhythm {
+            peak_hour_start,
+            peak_hour_end,
+            top_days,
+            sample_count,
+        } => InsightDto::Rhythm {
+            peak_hour_start,
+            peak_hour_end,
+            top_days,
+            sample_count,
+        },
+    }
+}
+
+/// Live insights for the authenticated user's own diary. Private surface:
+/// habits (late-night watching, mediums) are more sensitive than the taste
+/// statistics already public on profiles (ADR-0010).
+#[utoipa::path(
+    get, path = "/api/v1/insights",
+    params(InsightsQueryParams),
+    responses(
+        (status = 200, body = InsightsResponse),
+        (status = 400, description = "Unknown time zone"),
+        (status = 401, description = "Unauthorized"),
+    ),
+    security(("bearer_auth" = []))
+)]
+pub async fn get_insights(
+    State(state): State<AppState>,
+    user: AuthenticatedUser,
+    Query(params): Query<InsightsQueryParams>,
+) -> Result<Json<InsightsResponse>, ApiError> {
+    let tz: chrono_tz::Tz = match params.tz.as_deref() {
+        None => chrono_tz::UTC,
+        Some(name) => name.parse().map_err(|_| {
+            ApiError(DomainError::ValidationError(format!(
+                "unknown time zone: {name}"
+            )))
+        })?,
+    };
+    let insights = get_insights_uc::execute(&state.app_ctx.deps.insights.get, user.0, &tz).await?;
+    Ok(Json(InsightsResponse {
+        insights: insights.into_iter().map(to_dto).collect(),
+    }))
+}