use std::fmt::Display;

use jacquard_common::types::string::{Did, Handle};
use jacquard_common::{CowStr, IntoStatic};
use jacquard_repo::commit::Commit as AtpCommit;
#[cfg(feature = "indexer")]
use serde::{Deserialize, Serialize};
use smol_str::ToSmolStr;

use crate::db::types::{DbTid, DidKey};
use crate::resolver::MiniDoc;

#[cfg(any(feature = "indexer_stream", feature = "relay", feature = "jetstream"))]
pub(crate) mod event;
pub(crate) mod v2;
pub(crate) mod v4;
pub(crate) mod v7;

#[cfg(any(feature = "indexer_stream", feature = "relay", feature = "jetstream"))]
pub(crate) use event::*;
pub(crate) use v7::*;

/// which record-scoped body copies an operator redaction removes.
#[cfg(feature = "indexer")]
#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
#[serde(rename_all = "snake_case")]
pub enum DeleteBodyTarget {
    Head,
    History,
    All,
}

#[cfg(feature = "indexer")]
impl DeleteBodyTarget {
    pub(crate) fn includes_head(self) -> bool {
        matches!(self, Self::Head | Self::All)
    }

    pub(crate) fn includes_history(self) -> bool {
        matches!(self, Self::History | Self::All)
    }
}

/// idempotent result of deleting indexed body bytes while preserving logical
/// record identity and repository topology.
#[cfg(feature = "indexer")]
#[derive(Debug, Clone, Default, PartialEq, Eq, Serialize, Deserialize)]
pub struct DeleteBodiesReport {
    pub heads_redacted: u64,
    pub history_redacted: u64,
    pub event_bodies_redacted: u64,
    pub body_bytes_redacted: u64,
    pub buffered_commits_deleted: u64,
    pub buffered_commit_bytes_deleted: u64,
}

impl<S: jacquard_common::BosStr> From<AtpCommit<S>> for Commit {
    fn from(value: AtpCommit<S>) -> Self {
        Self {
            data: value.data,
            prev: value.prev,
            rev: DbTid::from(&value.rev),
            sig: value.sig,
            version: value.version,
        }
    }
}

impl Commit {
    pub(crate) fn into_atp_commit<S: jacquard_common::BosStr>(
        self,
        did: Did<S>,
    ) -> Option<AtpCommit<S>> {
        // version < 0 is a sentinel used in v2 migration for repos with no commit data
        if self.version < 0 {
            return None;
        }
        Some(AtpCommit {
            did,
            rev: self.rev.to_tid(),
            data: self.data,
            prev: self.prev,
            sig: self.sig,
            version: self.version,
        })
    }
}

impl Display for RepoStatus {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            RepoStatus::Synced => write!(f, "synced"),
            RepoStatus::Error(e) => write!(f, "error({e})"),
            RepoStatus::Deactivated => write!(f, "deactivated"),
            RepoStatus::Takendown => write!(f, "takendown"),
            RepoStatus::Suspended => write!(f, "suspended"),
            RepoStatus::Deleted => write!(f, "deleted"),
            RepoStatus::Desynchronized => write!(f, "desynchronized"),
            RepoStatus::Throttled => write!(f, "throttled"),
        }
    }
}

#[cfg(feature = "indexer")]
mod indexer {
    use super::*;

    impl RepoMetadata {
        pub fn backfilling(index_id: u64) -> Self {
            Self {
                index_id,
                tracked: true,
            }
        }
    }

    impl ResyncState {
        pub fn next_backoff(retry_count: u32) -> i64 {
            // exponential backoff: 1m, 2m, 4m, 8m... up to 1h
            let base = 60;
            let cap = 3600;
            let mult = 2u64.pow(retry_count.min(10)) as i64;
            let delay = (base * mult).min(cap);

            // add +/- 10% jitter
            let jitter = (rand::random::<f64>() * 0.2 - 0.1) * delay as f64;
            let delay = (delay as f64 + jitter) as i64;

            chrono::Utc::now().timestamp() + delay
        }
    }

    #[cfg(feature = "indexer_stream")]
    #[derive(Clone, Debug)]
    pub(crate) enum BroadcastEvent {
        Persisted(#[allow(dead_code)] u64),
        /// a durable record event with optional inline block bytes for live tailing.
        ///
        /// used to avoid re-reading the durable event and record body when tailing.
        LiveRecord(std::sync::Arc<super::LiveRecordEvent>),
        Ephemeral(Box<MarshallableEvt<'static>>),
    }

    #[derive(Debug, PartialEq, Eq, Clone, Copy)]
    pub(crate) enum GaugeState {
        Synced,
        Pending,
        Resync(Option<ResyncErrorKind>),
    }

    impl GaugeState {
        pub fn is_resync(&self) -> bool {
            matches!(self, GaugeState::Resync(_))
        }
    }
}

#[cfg(feature = "indexer")]
pub(crate) use indexer::*;

/// the identity a DID doc owns. it is the only part of a repo state that
/// resolving a doc rewrites, so consumers that cache it have to be told when it
/// moves instead of discovering it later.
#[derive(Debug, Clone, PartialEq)]
pub(crate) struct DocIdentity<'i> {
    handle: Option<Handle>,
    pds: Option<CowStr<'i>>,
    signing_key: Option<DidKey<'i>>,
}

impl<'i> RepoState<'i> {
    pub fn backfilling() -> Self {
        Self {
            active: true,
            status: RepoStatus::Desynchronized,
            root: None,
            last_updated_at: chrono::Utc::now().timestamp(),
            handle: None,
            pds: None,
            signing_key: None,
            last_message_time: None,
            last_identity_time: None,
            last_account_time: None,
        }
    }

    #[cfg(any(test, feature = "relay"))]
    pub fn synced() -> Self {
        Self {
            status: RepoStatus::Synced,
            ..Self::backfilling()
        }
    }

    // advances the high-water mark to event_ms if it's newer than what we've seen
    pub fn advance_message_time(&mut self, event_ms: i64) {
        self.last_message_time = Some(event_ms.max(self.last_message_time.unwrap_or(0)));
    }

    pub fn should_process_identity_time(&self, event_ms: i64) -> bool {
        self.last_identity_time.is_none_or(|t| event_ms > t)
    }

    pub fn advance_identity_time(&mut self, event_ms: i64) {
        self.last_identity_time = Some(event_ms.max(self.last_identity_time.unwrap_or(0)));
        self.advance_message_time(event_ms);
    }

    pub fn should_process_account_time(&self, event_ms: i64) -> bool {
        self.last_account_time.is_none_or(|t| event_ms > t)
    }

    pub fn advance_account_time(&mut self, event_ms: i64) {
        self.last_account_time = Some(event_ms.max(self.last_account_time.unwrap_or(0)));
        self.advance_message_time(event_ms);
    }

    // updates last_updated_at to now
    pub fn touch(&mut self) {
        self.last_updated_at = chrono::Utc::now().timestamp();
    }

    /// the doc-owned identity, the whole of what a resolve can rewrite.
    pub(crate) fn identity(&self) -> DocIdentity<'i> {
        DocIdentity {
            handle: self.handle.clone(),
            pds: self.pds.clone(),
            signing_key: self.signing_key.clone(),
        }
    }

    /// the identity moved, so anyone holding a cached copy must re-resolve it.
    #[cfg(any(test, feature = "indexer_stream"))]
    pub(crate) fn identity_moved_from(&self, previous: &Self) -> bool {
        self.identity() != previous.identity()
    }

    /// the account lifecycle moved. a first sighting of a pds counts as a move:
    /// nothing downstream keyed off an identity it never saw.
    #[cfg(any(test, feature = "indexer_stream"))]
    pub(crate) fn account_moved_from(&self, previous: &Self) -> bool {
        self.active != previous.active || self.status != previous.status || previous.pds.is_none()
    }

    pub fn update_from_doc(&mut self, doc: MiniDoc) -> bool {
        let previous = self.identity();
        self.pds = Some(CowStr::Owned(doc.pds.to_smolstr()));
        self.handle = doc.handle;
        self.signing_key = doc.key.map(From::from);
        self.identity() != previous
    }
}

impl<'i> IntoStatic for RepoState<'i> {
    type Output = RepoState<'static>;

    fn into_static(self) -> Self::Output {
        RepoState {
            active: self.active,
            status: self.status,
            root: self.root,
            last_updated_at: self.last_updated_at,
            handle: self.handle.map(IntoStatic::into_static),
            pds: self.pds.map(IntoStatic::into_static),
            signing_key: self.signing_key.map(IntoStatic::into_static),
            last_message_time: self.last_message_time,
            last_identity_time: self.last_identity_time,
            last_account_time: self.last_account_time,
        }
    }
}

#[cfg(feature = "indexer")]
#[derive(Debug, Clone, Copy, Serialize, Deserialize, PartialEq, Eq)]
pub(crate) enum ResyncErrorKind {
    Ratelimited,
    Transport,
    Generic,
}

#[cfg(feature = "indexer")]
#[derive(Debug, Clone, Serialize, Deserialize)]
pub(crate) enum ResyncState {
    Error {
        kind: ResyncErrorKind,
        retry_count: u32,
        next_retry: i64, // unix timestamp
    },
    Gone {
        status: RepoStatus, // deactivated, takendown, suspended
    },
}

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

    #[test]
    fn identity_moves_only_for_doc_owned_fields() -> miette::Result<()> {
        let mut previous = RepoState::synced();
        previous.pds = Some(CowStr::Borrowed("https://pds.example"));
        previous.handle = Some(Handle::new_static("alice.test").into_diagnostic()?);

        let mut state = previous.clone();
        state.advance_message_time(1_000);
        state.touch();
        state.root = previous.root.clone();
        assert!(!state.identity_moved_from(&previous));
        assert!(!state.account_moved_from(&previous));

        let mut handle_moved = previous.clone();
        handle_moved.handle = Some(Handle::new_static("carol.test").into_diagnostic()?);
        assert!(handle_moved.identity_moved_from(&previous));
        assert!(!handle_moved.account_moved_from(&previous));

        let mut pds_moved = previous.clone();
        pds_moved.pds = Some(CowStr::Borrowed("https://other.example"));
        assert!(pds_moved.identity_moved_from(&previous));

        let mut key_moved = previous.clone();
        key_moved.signing_key = Some(DidKey::from_did_key(
            "did:key:zQ3shokFTS3brHcDQrn82RUDfCZESWL1ZdCEJwekUDPQiYBme",
        )?);
        assert!(key_moved.identity_moved_from(&previous));

        let mut account_moved = previous.clone();
        account_moved.status = RepoStatus::Throttled;
        assert!(account_moved.account_moved_from(&previous));
        assert!(!account_moved.identity_moved_from(&previous));

        Ok(())
    }

    #[test]
    fn first_sighting_of_a_pds_moves_the_account() {
        let mut previous = RepoState::backfilling();
        previous.pds = None;

        let mut state = previous.clone();
        state.pds = Some(CowStr::Borrowed("https://pds.example"));

        assert!(state.account_moved_from(&previous));
        assert!(state.identity_moved_from(&previous));
    }

    #[test]
    fn identity_dedupe_does_not_depend_on_commit_clock() {
        let mut state = RepoState::backfilling();

        state.advance_message_time(2_000);

        assert!(state.should_process_identity_time(1_500));
        state.advance_identity_time(1_500);
        assert_eq!(state.last_message_time, Some(2_000));
        assert_eq!(state.last_identity_time, Some(1_500));

        assert!(!state.should_process_identity_time(1_500));
        assert!(!state.should_process_identity_time(1_499));
        assert!(state.should_process_identity_time(1_501));
    }

    #[test]
    fn account_dedupe_does_not_depend_on_commit_clock() {
        let mut state = RepoState::backfilling();

        state.advance_message_time(3_000);

        assert!(state.should_process_account_time(2_500));
        state.advance_account_time(2_500);
        assert_eq!(state.last_message_time, Some(3_000));
        assert_eq!(state.last_account_time, Some(2_500));

        assert!(!state.should_process_account_time(2_500));
        assert!(!state.should_process_account_time(2_499));
        assert!(state.should_process_account_time(2_501));
    }

    #[test]
    fn synced_state_is_active_without_backfilling_status() {
        let state = RepoState::synced();
        assert!(state.active);
        assert_eq!(state.status, RepoStatus::Synced);
        assert!(state.root.is_none());
    }

    #[test]
    fn into_static_preserves_per_event_clocks() -> miette::Result<()> {
        let mut state = RepoState::backfilling();
        state.last_message_time = Some(10);
        state.last_identity_time = Some(20);
        state.last_account_time = Some(30);
        state.handle = Some(Handle::new_static("alice.test").into_diagnostic()?);
        state.pds = Some(CowStr::Borrowed("https://pds.example"));
        state.signing_key = Some(DidKey::from_did_key(
            "did:key:zQ3shokFTS3brHcDQrn82RUDfCZESWL1ZdCEJwekUDPQiYBme",
        )?);

        let static_state = state.into_static();

        assert_eq!(static_state.last_message_time, Some(10));
        assert_eq!(static_state.last_identity_time, Some(20));
        assert_eq!(static_state.last_account_time, Some(30));

        Ok(())
    }

    #[test]
    fn commit_and_repo_status_conversion_contracts() {
        let did: Did = Did::new_static("did:plc:ewvi7nxzyoun6zhxrhs64oiz").unwrap();
        let rev = jacquard_common::types::tid::Tid::new("3jzfcijpj2z2a").unwrap();
        let data = jacquard_repo::mst::util::compute_cid(b"root").unwrap();
        let prev = jacquard_repo::mst::util::compute_cid(b"prev").unwrap();
        let atp = AtpCommit {
            did: did.clone(),
            version: 3,
            data,
            rev: rev.clone(),
            prev: Some(prev),
            sig: bytes::Bytes::from_static(b"\x01\x02\x03"),
        };

        let stored = Commit::from(atp);
        assert_eq!(stored.version, 3);
        assert_eq!(stored.data, data);
        assert_eq!(stored.prev, Some(prev));
        assert_eq!(stored.rev.to_tid(), rev);
        assert_eq!(stored.sig.as_ref(), b"\x01\x02\x03");

        let restored = stored.into_atp_commit(did.clone()).unwrap();
        assert_eq!(restored.did, did);
        assert_eq!(restored.version, 3);
        assert_eq!(restored.data, data);
        assert_eq!(restored.prev, Some(prev));
        assert_eq!(restored.rev, rev);
        assert_eq!(restored.sig.as_ref(), b"\x01\x02\x03");

        let mut sentinel = Commit::from(restored);
        sentinel.version = -1;
        assert!(sentinel.into_atp_commit(did).is_none());

        for (status, display) in [
            (RepoStatus::Synced, "synced"),
            (RepoStatus::Error("stinkpot".into()), "error(stinkpot)"),
            (RepoStatus::Deactivated, "deactivated"),
            (RepoStatus::Takendown, "takendown"),
            (RepoStatus::Suspended, "suspended"),
            (RepoStatus::Deleted, "deleted"),
            (RepoStatus::Desynchronized, "desynchronized"),
            (RepoStatus::Throttled, "throttled"),
        ] {
            assert_eq!(status.to_string(), display);
        }
    }
    #[cfg(feature = "indexer")]
    #[test]
    fn current_persisted_state_golden_fixtures() {
        let states = [
            ResyncState::Error {
                kind: ResyncErrorKind::Ratelimited,
                retry_count: 7,
                next_retry: -42,
            },
            ResyncState::Error {
                kind: ResyncErrorKind::Transport,
                retry_count: 8,
                next_retry: 0,
            },
            ResyncState::Error {
                kind: ResyncErrorKind::Generic,
                retry_count: 9,
                next_retry: 42,
            },
            ResyncState::Gone {
                status: RepoStatus::Deleted,
            },
        ];
        let encoded = states
            .iter()
            .map(|state| rmp_serde::to_vec(state).unwrap())
            .collect::<Vec<_>>();
        assert_eq!(
            encoded.iter().map(hex::encode).collect::<Vec<_>>(),
            [
                "81a54572726f7293ab526174656c696d6974656407d0d6",
                "81a54572726f7293a95472616e73706f72740800",
                "81a54572726f7293a747656e65726963092a",
                "81a4476f6e6591a744656c65746564",
            ]
        );
        assert!(matches!(
            rmp_serde::from_slice::<ResyncState>(&encoded[0]).unwrap(),
            ResyncState::Error {
                kind: ResyncErrorKind::Ratelimited,
                retry_count: 7,
                next_retry: -42,
            }
        ));
        assert!(matches!(
            rmp_serde::from_slice::<ResyncState>(&encoded[1]).unwrap(),
            ResyncState::Error {
                kind: ResyncErrorKind::Transport,
                retry_count: 8,
                next_retry: 0,
            }
        ));
        assert!(matches!(
            rmp_serde::from_slice::<ResyncState>(&encoded[2]).unwrap(),
            ResyncState::Error {
                kind: ResyncErrorKind::Generic,
                retry_count: 9,
                next_retry: 42,
            }
        ));
        assert!(matches!(
            rmp_serde::from_slice::<ResyncState>(&encoded[3]).unwrap(),
            ResyncState::Gone {
                status: RepoStatus::Deleted,
            }
        ));

        let metadata = RepoMetadata {
            tracked: true,
            index_id: 7,
        };
        let encoded = rmp_serde::to_vec(&metadata).unwrap();
        assert_eq!(hex::encode(&encoded), "92c307");
        let decoded: RepoMetadata = rmp_serde::from_slice(&encoded).unwrap();
        assert!(decoded.tracked);
        assert_eq!(decoded.index_id, 7);
    }

    #[cfg(feature = "indexer")]
    #[test]
    fn operator_redaction_json_contracts() {
        for (target, expected) in [
            (DeleteBodyTarget::Head, "\"head\""),
            (DeleteBodyTarget::History, "\"history\""),
            (DeleteBodyTarget::All, "\"all\""),
        ] {
            let encoded = serde_json::to_string(&target).unwrap();
            assert_eq!(encoded, expected);
            assert_eq!(
                serde_json::from_str::<DeleteBodyTarget>(&encoded).unwrap(),
                target
            );
        }

        let report = DeleteBodiesReport {
            heads_redacted: 1,
            history_redacted: 7,
            event_bodies_redacted: 3,
            body_bytes_redacted: 11,
            buffered_commits_deleted: 2,
            buffered_commit_bytes_deleted: 13,
        };
        let encoded = serde_json::to_value(&report).unwrap();
        assert_eq!(encoded["heads_redacted"], 1);
        assert_eq!(encoded["history_redacted"], 7);
        assert_eq!(encoded["event_bodies_redacted"], 3);
        assert_eq!(encoded["body_bytes_redacted"], 11);
        assert_eq!(encoded["buffered_commits_deleted"], 2);
        assert_eq!(encoded["buffered_commit_bytes_deleted"], 13);
    }
}