use chrono::{DateTime, Utc};
use serde::{Deserialize, Serialize};
use uuid::Uuid;

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Feed {
    pub id: Uuid,
    pub url: String,
    pub title: String,
    pub last_fetched_at: Option<DateTime<Utc>>,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Article {
    pub id: Uuid,
    pub feed_id: Uuid,
    pub url: String,
    pub title: String,
    pub summary: String,
    pub published_at: Option<DateTime<Utc>>,
    /// Short canonical tags assigned at ingest time (e.g. by the LLM stage),
    /// used both for display and as keys into `TopicAffinities`.
    pub topics: Vec<String>,
    /// Cosine similarity between the article embedding and the user's
    /// preference-profile embedding. Cheap first-pass filter score.
    pub embedding_score: Option<f32>,
    /// 0.0-1.0 relevance judgment from the LLM stage, only computed for
    /// articles that clear the embedding-score shortlist threshold.
    pub llm_score: Option<f32>,
    /// Final blended score actually used for ranking/surfacing, see
    /// `scoring::score_article`.
    pub final_score: Option<f32>,
    pub estimated_read_seconds: Option<u32>,
}

/// A single recorded interaction between the user and an article. Every
/// event is appended to an immutable log (see `feedsignal-db`); affinities
/// are derived from replaying/aggregating these, never mutated in place,
/// so the scoring model can be recomputed or tuned retroactively.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct ReadingEvent {
    pub id: Uuid,
    pub article_id: Uuid,
    pub occurred_at: DateTime<Utc>,
    pub outcome: ReadingOutcome,
}

#[derive(Debug, Clone, Serialize, Deserialize)]
pub enum ReadingOutcome {
    /// Shown in the feed list but no further interaction (yet).
    Impression,
    /// User opened the article. `dwell_seconds` is filled in later via an
    /// update event (e.g. on tab close / navigation away) once known.
    Opened { dwell_seconds: Option<u32> },
    Starred,
    /// Explicitly marked not relevant, independent of whether it was opened.
    Dismissed,
}