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

#[derive(Debug, Clone, Serialize, Deserialize, FromRow)]
pub struct ReadProgress {
    pub user_id: Uuid,
    pub manga_id: Uuid,
    pub chapter_id: Option<Uuid>,
    pub page: i32,
    pub updated_at: DateTime<Utc>,
}

/// Enriched row for the history view — joins in the manga's title and
/// cover plus the chapter number (when the chapter still exists) so a
/// card can render without extra round-trips.
#[derive(Debug, Clone, Serialize, FromRow)]
pub struct ReadProgressSummary {
    pub manga_id: Uuid,
    pub manga_title: String,
    pub manga_cover_image_path: Option<String>,
    pub chapter_id: Option<Uuid>,
    /// `None` when the chapter was deleted after this row was written
    /// (FK ON DELETE SET NULL on `chapter_id`).
    pub chapter_number: Option<i32>,
    /// Page count of the last-read chapter (`None` when unknown / deleted).
    /// Lets a client distinguish a finished series (read to the last page,
    /// nothing new) from one still in progress — e.g. to keep finished
    /// series off a "Continue reading" shelf.
    pub chapter_page_count: Option<i32>,
    pub page: i32,
    pub updated_at: DateTime<Utc>,
    /// How many chapters sit past the reader's last-read chapter (by
    /// chapter number) — a personal "new since you last read" count.
    /// `0` when the reader is caught up or when `chapter_number` is
    /// unknown (manga-level progress or a deleted chapter), so we never
    /// claim chapters are new when we can't place the reader.
    pub new_chapters_count: i64,
}

/// Returned by `GET /me/read-progress/:manga_id`. Same shape as
/// `ReadProgressSummary` minus the manga title/cover (the caller
/// already knows them — they're on the manga detail page). Crucially
/// includes `chapter_number` so the "Continue reading" CTA can render
/// without resolving the chapter id against a paged chapters list.
#[derive(Debug, Clone, Serialize, FromRow)]
pub struct ReadProgressForManga {
    pub manga_id: Uuid,
    pub chapter_id: Option<Uuid>,
    pub chapter_number: Option<i32>,
    pub page: i32,
    pub updated_at: DateTime<Utc>,
    /// Distinct chapter numbers past the last-read chapter — the detail
    /// page's authoritative "new since last read" count (computed over all
    /// chapters, not the client's paginated list). `0` when caught up or
    /// the position is unknown. See [`ReadProgressSummary::new_chapters_count`].
    pub new_chapters_count: i64,
}

#[derive(Debug, Clone, Deserialize)]
pub struct UpsertReadProgress {
    pub manga_id: Uuid,
    pub chapter_id: Option<Uuid>,
    pub page: Option<i32>,
}