//! Jmanifest wire types (§2).
//!
//! **`#[serde(deny_unknown_fields)]` on every struct is the §6 stage 2
//! enforcement mechanism.** "No additional fields anywhere" is a property of
//! these type definitions rather than of validator code that could omit a
//! field, so an unrecognised key at any nesting level fails to parse. That is
//! also what makes the §9 `movie`/`jellyfin_id` strip verifiable: a client that
//! forgets gets a hard `400` naming the field, rather than quietly publishing a
//! contributor's directory layout.
//!
//! Deeper semantic checks — bounds, character classes, path-shaped strings —
//! live in [`crate::validate`]. Parsing rejects *shape*; validation rejects
//! *content*.

use serde::{Deserialize, Serialize};

/// Cut-match tier (§3). Ordered worst-to-best so derived `Ord` ranks them.
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Serialize, Deserialize)]
#[serde(rename_all = "lowercase")]
pub enum MatchTier {
    /// No cut information was supplied, so alignment is unknown (§4).
    Unknown,
    /// Audio 0.60–0.85, or runtimes within ±30s. Caveat in UI.
    Loose,
    /// Runtimes within ±2s.
    Runtime,
    /// Audio score ≥ 0.85; the top tier, and content-derived.
    Audio,
}

impl MatchTier {
    pub fn as_str(self) -> &'static str {
        match self {
            MatchTier::Unknown => "unknown",
            MatchTier::Loose => "loose",
            MatchTier::Runtime => "runtime",
            MatchTier::Audio => "audio",
        }
    }
}

#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
#[serde(rename_all = "lowercase")]
pub enum IdentityType {
    Movie,
    Episode,
}

/// What the work is (§2 terminology: *title identity*).
///
/// Movie and episode coordinates share one struct because `deny_unknown_fields`
/// with `#[serde(untagged)]` alternatives produces unhelpful error messages;
/// the discriminant is checked in [`crate::validate`], which can name the
/// offending field.
#[derive(Debug, Clone, Deserialize, Serialize)]
#[serde(deny_unknown_fields)]
pub struct Identity {
    #[serde(rename = "type")]
    pub kind: IdentityType,

    // Movie coordinates.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub tmdb_id: Option<String>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub imdb_id: Option<String>,

    // Episode coordinates.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub series_tmdb_id: Option<String>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub series_imdb_id: Option<String>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub season: Option<i64>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub episode: Option<i64>,

    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub title: Option<String>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub year: Option<i64>,
}

impl Identity {
    /// The TMDB id used as the lookup key, whichever coordinate carries it.
    pub fn effective_tmdb_id(&self) -> Option<&str> {
        match self.kind {
            IdentityType::Movie => self.tmdb_id.as_deref(),
            IdentityType::Episode => self.series_tmdb_id.as_deref(),
        }
    }

    pub fn effective_imdb_id(&self) -> Option<&str> {
        match self.kind {
            IdentityType::Movie => self.imdb_id.as_deref(),
            IdentityType::Episode => self.series_imdb_id.as_deref(),
        }
    }
}

/// Which encode/edit the timings apply to (§2 terminology: *cut fingerprint*).
#[derive(Debug, Clone, Deserialize, Serialize)]
#[serde(deny_unknown_fields)]
pub struct Cut {
    /// **Required** — the decoded duration of the media the timings came from.
    /// The primary alignment guard (§2).
    pub runtime_sec: f64,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub container_duration_sec: Option<f64>,
    /// Optional; version-prefixed spectral-peak signature (§3, UR-9).
    ///
    /// Accepted and stored by this build; `audio`-tier matching is enabled once
    /// coverage is useful, per §3's recommended sequencing.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub audio_signature: Option<String>,
}

/// How well the contributor's gallery could discriminate (§2, §7).
///
/// The strongest available quality signal between two otherwise comparable
/// manifests: a `Global` gallery had to distinguish its actors from every other
/// actor in the contributor's library, whereas a `Limited` one only had to
/// distinguish them from this title's own cast.
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Deserialize, Serialize)]
#[serde(rename_all = "lowercase")]
pub enum GalleryScope {
    /// Built from this title's cast alone.
    Limited,
    /// Built from the whole library. The default upstream.
    Global,
}

impl GalleryScope {
    pub fn as_str(self) -> &'static str {
        match self {
            GalleryScope::Limited => "limited",
            GalleryScope::Global => "global",
        }
    }
}

/// Extraction parameters, carried for provenance and ranking.
///
/// Note there is no `anneal_sec`: it was **withdrawn** in the SR-003 schema
/// bump, because presence now follows track extent — a track survives its own
/// gaps, so there is nothing to anneal (`scene-actor-extraction` AR-012/AR-013).
/// `deny_unknown_fields` therefore makes its presence a hard parse error rather
/// than something silently ignored, which is deliberate: a manifest still
/// carrying it was produced by a pipeline whose window semantics differ from
/// what this server now assumes.
/// TRACES: UR-003, UR-011 | SR-004
#[derive(Debug, Clone, Deserialize, Serialize)]
#[serde(deny_unknown_fields)]
pub struct Extraction {
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub sample_fps: Option<f64>,
    /// The re-acquisition timeout that shapes window extent. Successor to the
    /// withdrawn `anneal_sec`.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub extinction_sec: Option<f64>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub pipeline_version: Option<String>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub gallery_size: Option<i64>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub gallery_scope: Option<GalleryScope>,
}

/// One actor's timeline.
///
/// Note there is no `jellyfin_id` field: `deny_unknown_fields` means its
/// presence is a parse error, which is exactly the §2/§6 requirement that it be
/// *rejected on upload* rather than merely ignored on download.
/// TRACES: UR-010, UR-013 | SR-001, SR-002
#[derive(Debug, Clone, Deserialize, Serialize)]
#[serde(deny_unknown_fields)]
pub struct Actor {
    /// Sent on upload for matching, but **not persisted** — the server resolves
    /// each actor to a TMDB person id and serves names from its own TMDB-derived
    /// table (§2, §5a). On download this is server-authoritative.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub name: Option<String>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub imdb_id: Option<String>,
    /// The **primary** actor join key (§2, §6 stage 3).
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub tmdb_id: Option<String>,
    /// Presence windows, inclusive and sorted by start.
    pub scenes: Vec<Scene>,
}

/// TRACES: UR-017 | SR-003
/// How an actor was identified for a given window (`scene-actor-extraction`
/// AR-017: every presence claim carries its belief and identification route).
#[derive(Debug, Clone, Copy, PartialEq, Eq, Deserialize, Serialize)]
#[serde(rename_all = "lowercase")]
pub enum Route {
    /// Identified while the track was live.
    Live,
    /// Resolved by the deferred pass, after the final frame was read.
    Deferred,
    /// Resolved from the per-subject embedding pool.
    Pooled,
}

impl Route {
    pub fn as_str(self) -> &'static str {
        match self {
            Route::Live => "live",
            Route::Deferred => "deferred",
            Route::Pooled => "pooled",
        }
    }

    /// Parses a value read back from storage. Returns `None` for anything
    /// unrecognised rather than guessing — a row written by a future schema
    /// means something this build does not know, and inventing a route would
    /// misreport provenance.
    ///
    /// Deliberately not `FromStr`: that trait is for parsing *input*, and this
    /// reads a value the server itself wrote from a closed enum. Keeping them
    /// distinct stops a future refactor pointing user input at this path.
    pub fn from_stored(s: &str) -> Option<Self> {
        match s {
            "live" => Some(Route::Live),
            "deferred" => Some(Route::Deferred),
            "pooled" => Some(Route::Pooled),
            _ => None,
        }
    }
}

/// TRACES: UR-013, UR-017 | SR-002, SR-003
/// One presence window.
///
/// **A window is a claim about scene membership, not a recognition event**
/// (SR-002, UR-013). An actor who turns away or is off-camera during a reverse
/// shot is still present, so the server never merges, splits or trims these —
/// it stores what it was given, quantised but not reshaped.
///
/// `belief` and `route` are **excluded from `content_id`** (§9a). Belief is a
/// producer-side estimate that may legitimately differ between pipeline versions
/// for identical timings, so including it would give two servers different ids
/// for the same content — the exact failure mode §9a quantises centiseconds to
/// avoid. They replicate as attributes, exactly as `audio_signature` does.
#[derive(Debug, Clone, Copy, Deserialize, Serialize)]
#[serde(deny_unknown_fields)]
pub struct Scene {
    pub start: f64,
    pub end: f64,
    /// Accumulated posterior that justified the claim, in `[0, 1]`.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub belief: Option<f64>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub route: Option<Route>,
}

/// One shareable actor timeline for one cut of one title (§2).
/// TRACES: UR-003, UR-011, UR-014 | SR-003, SR-004
#[derive(Debug, Clone, Deserialize, Serialize)]
#[serde(deny_unknown_fields)]
pub struct Jmanifest {
    pub jmanifest_version: u32,
    pub identity: Identity,
    pub cut: Cut,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub extraction: Option<Extraction>,
    pub actors: Vec<Actor>,
}

/// Series-level coordinates for a bundle envelope (§2).
#[derive(Debug, Clone, Deserialize, Serialize)]
#[serde(deny_unknown_fields)]
pub struct SeriesRef {
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub series_tmdb_id: Option<String>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub series_imdb_id: Option<String>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub title: Option<String>,
}

/// A thin wrapper, not a new format (§2). Bundles are a transfer convenience,
/// never a storage unit — each episode is stored and moderated individually.
#[derive(Debug, Clone, Deserialize, Serialize)]
#[serde(deny_unknown_fields)]
pub struct SeriesBundle {
    pub jmanifest_version: u32,
    pub series: SeriesRef,
    pub episodes: Vec<Jmanifest>,
    /// Present on responses only; ignored on upload.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub coverage: Option<Coverage>,
}

#[derive(Debug, Clone, Deserialize, Serialize)]
#[serde(deny_unknown_fields)]
pub struct Coverage {
    pub episodes_available: usize,
    pub seasons: Vec<i64>,
}

/// The current `jmanifest_version` this server speaks (§2).
///
/// Bumped to 2 with the SR-003 schema change, in lockstep with the truth file's
/// `schema_version` — breaking changes are batched and ship together across all
/// three repos, so a component moving alone is the defect this coordination
/// exists to prevent.
///
/// **Flag day, not dual-accept** (SR-003, `jRay` JR-003). Version 1 is rejected
/// outright rather than carried alongside: all three components are pre-release,
/// and a v1 read path would be the one nobody exercises, so it is the one that
/// would rot while being dragged through every later change to the reader.
///
/// The two version fields remain *independent by design* — `jmanifest_version`
/// versions the exchange envelope, `schema_version` the truth file — and they
/// coincide at 2 only because this bump touched both.
pub const JMANIFEST_VERSION: u32 = 2;

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn unknown_field_at_top_level_is_rejected() {
        let json = r#"{"jmanifest_version":2,"identity":{"type":"movie","tmdb_id":"1"},
            "cut":{"runtime_sec":100.0},"actors":[],"surprise":"x"}"#;
        let err = serde_json::from_str::<Jmanifest>(json).unwrap_err().to_string();
        assert!(err.contains("surprise"), "error should name the field: {err}");
    }

    #[test]
    fn jellyfin_id_on_an_actor_is_a_parse_error() {
        // §2: `actors[].jellyfin_id` must not appear. `deny_unknown_fields`
        // makes this structural rather than a validator's responsibility.
        let json = r#"{"jmanifest_version":2,"identity":{"type":"movie","tmdb_id":"1"},
            "cut":{"runtime_sec":100.0},
            "actors":[{"name":"A","tmdb_id":"2","jellyfin_id":"guid","scenes":[]}]}"#;
        let err = serde_json::from_str::<Jmanifest>(json).unwrap_err().to_string();
        assert!(err.contains("jellyfin_id"), "error should name the field: {err}");
    }

    #[test]
    fn movie_path_field_is_a_parse_error() {
        let json = r#"{"jmanifest_version":2,"movie":"/data/movies/x.mkv",
            "identity":{"type":"movie","tmdb_id":"1"},
            "cut":{"runtime_sec":100.0},"actors":[]}"#;
        let err = serde_json::from_str::<Jmanifest>(json).unwrap_err().to_string();
        assert!(err.contains("movie"), "error should name the field: {err}");
    }

    #[test]
    fn unknown_field_nested_in_cut_is_rejected() {
        let json = r#"{"jmanifest_version":2,"identity":{"type":"movie","tmdb_id":"1"},
            "cut":{"runtime_sec":100.0,"payload":"x"},"actors":[]}"#;
        assert!(serde_json::from_str::<Jmanifest>(json).is_err());
    }

    #[test]
    fn spec_example_manifest_parses() {
        let json = r#"{
          "jmanifest_version": 2,
          "identity": { "type": "movie", "tmdb_id": "504172", "imdb_id": "tt4686844",
                        "title": "The Death of Stalin", "year": 2017 },
          "cut": { "runtime_sec": 6420.5, "container_duration_sec": 6420.5 },
          "extraction": { "sample_fps": 5, "extinction_sec": 12,
                          "pipeline_version": "scene-actor-extraction 0.4.1",
                          "gallery_size": 1820, "gallery_scope": "global" },
          "actors": [ { "name": "Steve Buscemi", "imdb_id": "nm0000114", "tmdb_id": "884",
                        "scenes": [
                          { "start": 191.6, "end": 209.2, "belief": 0.98, "route": "live" },
                          { "start": 438.2, "end": 465.6, "belief": 0.81, "route": "deferred" }
                        ] } ]
        }"#;
        let m: Jmanifest = serde_json::from_str(json).unwrap();
        assert_eq!(m.actors.len(), 1);
        assert_eq!(m.identity.effective_tmdb_id(), Some("504172"));
    }

    #[test]
    fn tiers_order_audio_above_runtime() {
        // §3: `audio` is the top tier, and ranks above `runtime` because it is
        // content-derived where equal runtimes are only circumstantial.
        assert!(MatchTier::Audio > MatchTier::Runtime);
        assert!(MatchTier::Runtime > MatchTier::Loose);
    }

    #[test]
    fn withdrawn_video_hash_is_rejected_as_an_unknown_field() {
        // §3: withdrawn, and `deny_unknown_fields` is what enforces it. A
        // contributor still sending it gets a `400` naming the field rather
        // than having it silently dropped.
        let json = r#"{"jmanifest_version":2,"identity":{"type":"movie","tmdb_id":"1"},
            "cut":{"runtime_sec":100.0,"video_hash":"opensubtitles:8e245d9679d31e12"},
            "actors":[]}"#;
        let err = serde_json::from_str::<Jmanifest>(json).unwrap_err().to_string();
        assert!(err.contains("video_hash"), "error should name the field: {err}");
    }
}