use std::sync::Arc;

use crate::integrate::authored_ops_to_dht_db;
use crate::integrate::authored_ops_to_dht_db_without_check;
use crate::scratch::ScratchError;
use crate::scratch::SyncScratchError;
use async_recursion::async_recursion;
use holo_hash::AgentPubKey;
use holo_hash::DhtOpHash;
use holo_hash::DnaHash;
use holo_hash::HasHash;
use holo_hash::HeaderHash;
use holochain_keystore::MetaLairClient;
use holochain_p2p::HolochainP2pDnaT;
use holochain_sqlite::rusqlite::Transaction;
use holochain_types::dht_op::produce_op_lights_from_elements;
use holochain_types::dht_op::produce_op_lights_from_iter;
use holochain_types::dht_op::DhtOp;
use holochain_types::dht_op::DhtOpLight;
use holochain_types::dht_op::OpOrder;
use holochain_types::dht_op::UniqueForm;
use holochain_types::element::SignedHeaderHashedExt;
use holochain_types::env::DbRead;
use holochain_types::env::DbWrite;
use holochain_zome_types::entry::EntryHashed;
use holochain_zome_types::header;
use holochain_zome_types::query::ChainQueryFilterRange;
use holochain_zome_types::CapAccess;
use holochain_zome_types::CapGrant;
use holochain_zome_types::CapSecret;
use holochain_zome_types::CellId;
use holochain_zome_types::ChainTopOrdering;
use holochain_zome_types::CounterSigningAgentState;
use holochain_zome_types::CounterSigningSessionData;
use holochain_zome_types::Element;
use holochain_zome_types::Entry;
use holochain_zome_types::EntryVisibility;
use holochain_zome_types::GrantedFunction;
use holochain_zome_types::Header;
use holochain_zome_types::HeaderBuilder;
use holochain_zome_types::HeaderBuilderCommon;
use holochain_zome_types::HeaderHashed;
use holochain_zome_types::HeaderInner;
use holochain_zome_types::PreflightRequest;
use holochain_zome_types::QueryFilter;
use holochain_zome_types::Signature;
use holochain_zome_types::SignedHeader;
use holochain_zome_types::SignedHeaderHashed;
use holochain_zome_types::Timestamp;
use holochain_zome_types::Zome;

use crate::chain_lock::is_chain_locked;
use crate::chain_lock::is_lock_expired;
use crate::prelude::*;
use crate::query::chain_head::ChainHeadQuery;
use crate::scratch::Scratch;
use crate::scratch::SyncScratch;
use holo_hash::EntryHash;
use holochain_serialized_bytes::prelude::*;

pub use error::*;

mod error;

#[derive(Clone)]
pub struct SourceChain<AuthorDb = DbWrite<DbKindAuthored>, DhtDb = DbWrite<DbKindDht>> {
    scratch: SyncScratch,
    vault: AuthorDb,
    dht_env: DhtDb,
    keystore: MetaLairClient,
    author: Arc<AgentPubKey>,
    persisted_seq: u32,
    persisted_head: HeaderHash,
    persisted_timestamp: Timestamp,
    public_only: bool,
}

/// A source chain with read only access to the underlying databases.
pub type SourceChainRead = SourceChain<DbRead<DbKindAuthored>, DbRead<DbKindDht>>;

// TODO fix this.  We shouldn't really have nil values but this would
// show if the database is corrupted and doesn't have an element
#[derive(Serialize, Debug, Clone, Deserialize)]
pub struct SourceChainJsonDump {
    pub elements: Vec<SourceChainJsonElement>,
    pub published_ops_count: usize,
}

#[derive(Serialize, Debug, Clone, Deserialize)]
pub struct SourceChainJsonElement {
    pub signature: Signature,
    pub header_address: HeaderHash,
    pub header: Header,
    pub entry: Option<Entry>,
}

// TODO: document that many functions here are only reading from the scratch,
//       not the entire source chain!
/// Writable functions for a source chain with write access.
impl SourceChain {
    pub async fn unlock_chain(&self) -> SourceChainResult<()> {
        let author = self.author.clone();
        self.vault
            .async_commit(move |txn| unlock_chain(txn, &author))
            .await?;
        Ok(())
    }

    pub async fn accept_countersigning_preflight_request(
        &self,
        preflight_request: PreflightRequest,
        agent_index: u8,
    ) -> SourceChainResult<CounterSigningAgentState> {
        let hashed_preflight_request = holo_hash::encode::blake2b_256(
            &holochain_serialized_bytes::encode(&preflight_request)?,
        );

        // This all needs to be ensured in a non-panicky way BEFORE calling into the source chain here.
        let author = self.author.clone();
        assert_eq!(
            *author,
            preflight_request.signing_agents()[agent_index as usize].0
        );

        let countersigning_agent_state = self
            .vault
            .async_commit(move |txn| {
                if is_chain_locked(txn, &hashed_preflight_request, author.as_ref())? {
                    return Err(SourceChainError::ChainLocked);
                }
                let (persisted_head, persisted_seq, _) = chain_head_db(txn, author.clone())?;
                let countersigning_agent_state =
                    CounterSigningAgentState::new(agent_index, persisted_head, persisted_seq);
                lock_chain(
                    txn,
                    &hashed_preflight_request,
                    author.as_ref(),
                    preflight_request.session_times().end(),
                )?;
                SourceChainResult::Ok(countersigning_agent_state)
            })
            .await?;
        Ok(countersigning_agent_state)
    }

    pub async fn put_with_header(
        &self,
        zome: Option<Zome>,
        header: Header,
        maybe_entry: Option<Entry>,
        chain_top_ordering: ChainTopOrdering,
    ) -> SourceChainResult<HeaderHash> {
        let header = HeaderHashed::from_content_sync(header);
        let hash = header.as_hash().clone();
        let header = SignedHeaderHashed::new(&self.keystore, header).await?;
        let element = Element::new(header, maybe_entry);
        self.scratch
            .apply(|scratch| insert_element_scratch(scratch, zome, element, chain_top_ordering))?;
        Ok(hash)
    }

    pub async fn put_countersigned(
        &self,
        zome: Option<Zome>,
        entry: Entry,
        chain_top_ordering: ChainTopOrdering,
    ) -> SourceChainResult<HeaderHash> {
        let entry_hash = EntryHash::with_data_sync(&entry);
        if let Entry::CounterSign(ref session_data, _) = entry {
            self.put_with_header(
                zome,
                Header::from_countersigning_data(entry_hash, session_data, (*self.author).clone())?,
                Some(entry),
                chain_top_ordering,
            )
            .await
        } else {
            // The caller MUST guard against this case.
            unreachable!("Put countersigned called with the wrong entry type");
        }
    }

    pub async fn put<H: HeaderInner, B: HeaderBuilder<H>>(
        &self,
        zome: Option<Zome>,
        header_builder: B,
        maybe_entry: Option<Entry>,
        chain_top_ordering: ChainTopOrdering,
    ) -> SourceChainResult<HeaderHash> {
        let (prev_header, chain_head_seq, chain_head_timestamp) = self.chain_head()?;
        let header_seq = chain_head_seq + 1;

        // Build the header.
        let common = HeaderBuilderCommon {
            author: (*self.author).clone(),
            // If the current time is equal to the current chain head timestamp,
            // or even has drifted to be before it, just set the next timestamp
            // to be one unit ahead of the previous.
            //
            // TODO: put a limit on the size of the negative time interval
            //       we are willing to accept, beyond which we emit an error
            //       rather than bumping the timestamp
            timestamp: std::cmp::max(
                Timestamp::now(),
                (chain_head_timestamp + std::time::Duration::from_micros(1))?,
            ),
            header_seq,
            prev_header,
        };
        self.put_with_header(
            zome,
            header_builder.build(common).into(),
            maybe_entry,
            chain_top_ordering,
        )
        .await
    }

    #[async_recursion]
    pub async fn flush(
        &self,
        network: &(dyn HolochainP2pDnaT + Send + Sync),
    ) -> SourceChainResult<Vec<(Option<Zome>, SignedHeaderHashed)>> {
        // Nothing to write
        if self.scratch.apply(|s| s.is_empty())? {
            return Ok(Vec::new());
        }
        let (scheduled_fns, zomed_headers, ops, entries) =
            self.scratch.apply_and_then(|scratch| {
                let (zomed_headers, ops) =
                    build_ops_from_headers(scratch.drain_zomed_headers().collect::<Vec<_>>())?;

                // Drain out any entries.
                let entries = scratch.drain_entries().collect::<Vec<_>>();
                let scheduled_fns = scratch.drain_scheduled_fns().collect::<Vec<_>>();
                SourceChainResult::Ok((scheduled_fns, zomed_headers, ops, entries))
            })?;

        let maybe_countersigned_entry = entries
            .iter()
            .map(|entry| entry.as_content())
            .find(|entry| matches!(entry, Entry::CounterSign(_, _)));

        if matches!(maybe_countersigned_entry, Some(Entry::CounterSign(_, _)))
            && zomed_headers.len() != 1
        {
            return Err(SourceChainError::DirtyCounterSigningWrite);
        }
        let lock = lock_for_entry(maybe_countersigned_entry)?;

        // If the lock isn't empty this is a countersigning session.
        let is_countersigning_session = !lock.is_empty();

        let ops_to_integrate = ops
            .iter()
            .map(|op| (op.1.clone(), op.0.dht_basis().clone()))
            .collect::<Vec<_>>();

        // Write the entries, headers and ops to the database in one transaction.
        let author = self.author.clone();
        let persisted_head = self.persisted_head.clone();
        match self
            .vault
            .async_commit(move |txn: &mut Transaction| {
                let now = Timestamp::now();
                for scheduled_fn in scheduled_fns {
                    schedule_fn(txn, author.as_ref(), scheduled_fn, None, now)?;
                }
                // As at check.
                let (new_persisted_head, new_head_seq, new_timestamp) =
                    chain_head_db(txn, author.clone())?;
                if zomed_headers.last().is_none() {
                    // Nothing to write
                    return Ok(Vec::new());
                }
                if persisted_head != new_persisted_head {
                    return Err(SourceChainError::HeadMoved(
                        zomed_headers,
                        entries,
                        Some(persisted_head),
                        Some((new_persisted_head, new_head_seq, new_timestamp)),
                    ));
                }

                if is_chain_locked(txn, &lock, author.as_ref())? {
                    return Err(SourceChainError::ChainLocked);
                }
                // If this is a countersigning session, and the chain is NOT
                // locked then either the session expired or the countersigning
                // entry being committed now is the correct one for the lock.
                else if is_countersigning_session {
                    // If the lock is expired then we can't write this countersigning session.
                    if is_lock_expired(txn, &lock, author.as_ref())? {
                        return Err(SourceChainError::LockExpired);
                    }
                }

                for entry in entries {
                    insert_entry(txn, entry)?;
                }
                for shh in zomed_headers.iter().map(|(_zome, shh)| shh) {
                    insert_header(txn, shh.clone())?;
                }
                for (op, op_hash, op_order, timestamp, _) in ops {
                    insert_op_lite_into_authored(txn, op, op_hash.clone(), op_order, timestamp)?;
                    // If this is a countersigning session we want to withhold
                    // publishing the ops until the session is successful.
                    if is_countersigning_session {
                        set_withhold_publish(txn, op_hash)?;
                    }
                }
                SourceChainResult::Ok(zomed_headers)
            })
            .await
        {
            Err(SourceChainError::HeadMoved(
                zomed_headers,
                entries,
                old_head,
                Some((new_persisted_head, new_head_seq, new_timestamp)),
            )) => {
                let is_relaxed =
                    self.scratch
                        .apply_and_then::<bool, SyncScratchError, _>(|scratch| {
                            Ok(scratch.chain_top_ordering() == ChainTopOrdering::Relaxed)
                        })?;
                if is_relaxed {
                    let keystore = self.keystore.clone();
                    // A child chain is needed with a new as-at that matches
                    // the rebase.
                    let child_chain = Self::new(
                        self.vault.clone(),
                        self.dht_env.clone(),
                        keystore.clone(),
                        (*self.author).clone(),
                    )
                    .await?;
                    let rebased_headers = rebase_headers_on(
                        &keystore,
                        zomed_headers,
                        new_persisted_head,
                        new_head_seq,
                        new_timestamp,
                    )
                    .await?;
                    child_chain.scratch.apply(move |scratch| {
                        for (zome, header) in rebased_headers {
                            scratch.add_header(zome, header, ChainTopOrdering::Relaxed);
                        }
                        for entry in entries {
                            scratch.add_entry(entry, ChainTopOrdering::Relaxed);
                        }
                    })?;
                    child_chain.flush(network).await
                } else {
                    Err(SourceChainError::HeadMoved(
                        zomed_headers,
                        entries,
                        old_head,
                        Some((new_persisted_head, new_head_seq, new_timestamp)),
                    ))
                }
            }
            Ok(zomed_headers) => {
                authored_ops_to_dht_db(network, ops_to_integrate, &self.vault, &self.dht_env)
                    .await?;
                SourceChainResult::Ok(zomed_headers)
            }
            result => result,
        }
    }
}

impl<AuthorDb, DhtDb> SourceChain<AuthorDb, DhtDb>
where
    AuthorDb: ReadAccess<DbKindAuthored>,
    DhtDb: ReadAccess<DbKindDht>,
{
    pub async fn new(
        vault: AuthorDb,
        dht_env: DhtDb,
        keystore: MetaLairClient,
        author: AgentPubKey,
    ) -> SourceChainResult<Self> {
        let scratch = Scratch::new().into_sync();
        let author = Arc::new(author);
        let (persisted_head, persisted_seq, persisted_timestamp) = vault
            .async_reader({
                let author = author.clone();
                move |txn| chain_head_db(&txn, author)
            })
            .await?;
        Ok(Self {
            scratch,
            vault,
            dht_env,
            keystore,
            author,
            persisted_seq,
            persisted_head,
            persisted_timestamp,
            public_only: false,
        })
    }

    /// Create a source chain with a blank chain head.
    /// You probably don't want this.
    /// This type is only useful for when a source chain
    /// really needs to be constructed before genesis runs.
    pub async fn raw_empty(
        vault: AuthorDb,
        dht_env: DhtDb,
        keystore: MetaLairClient,
        author: AgentPubKey,
    ) -> SourceChainResult<Self> {
        let scratch = Scratch::new().into_sync();
        let author = Arc::new(author);
        let (persisted_head, persisted_seq, persisted_timestamp) = vault
            .async_reader({
                let author = author.clone();
                move |txn| chain_head_db(&txn, author)
            })
            .await
            .unwrap_or_else(|_| {
                (
                    HeaderHash::from_raw_32(vec![0u8; 32]),
                    0,
                    Timestamp::from_micros(0),
                )
            });
        Ok(Self {
            scratch,
            vault,
            dht_env,
            keystore,
            author,
            persisted_seq,
            persisted_head,
            persisted_timestamp,
            public_only: false,
        })
    }

    pub fn public_only(&mut self) {
        self.public_only = true;
    }

    pub fn keystore(&self) -> &MetaLairClient {
        &self.keystore
    }

    pub fn author_db(&self) -> &AuthorDb {
        &self.vault
    }

    /// Take a snapshot of the scratch space that will
    /// not remain in sync with future updates.
    pub fn snapshot(&self) -> SourceChainResult<Scratch> {
        Ok(self.scratch.apply(|scratch| scratch.clone())?)
    }

    pub fn scratch(&self) -> SyncScratch {
        self.scratch.clone()
    }

    pub fn agent_pubkey(&self) -> &AgentPubKey {
        self.author.as_ref()
    }

    pub fn to_agent_pubkey(&self) -> Arc<AgentPubKey> {
        self.author.clone()
    }

    pub fn cell_id(&self) -> CellId {
        CellId::new(
            self.vault.kind().dna_hash().clone(),
            self.agent_pubkey().clone(),
        )
    }

    /// This has to clone all the data because we can't return
    /// references to constructed data.
    // TODO: Maybe we should store data as elements in the scratch?
    // TODO: document that this is only the elements in the SCRATCH, not the
    //       entire source chain!
    pub fn scratch_elements(&self) -> SourceChainResult<Vec<Element>> {
        Ok(self.scratch.apply(|scratch| scratch.elements().collect())?)
    }

    pub fn has_initialized(&self) -> SourceChainResult<bool> {
        Ok(self.len()? > 3)
    }

    pub fn is_empty(&self) -> SourceChainResult<bool> {
        Ok(self.len()? == 0)
    }

    /// Accessor for the chain head that will be used at flush time to check
    /// the "as at" for ordering integrity etc.
    pub fn persisted_chain_head(&self) -> (HeaderHash, u32, Timestamp) {
        (
            self.persisted_head.clone(),
            self.persisted_seq,
            self.persisted_timestamp,
        )
    }

    pub fn chain_head(&self) -> SourceChainResult<(HeaderHash, u32, Timestamp)> {
        // Check scratch for newer head.
        Ok(self.scratch.apply(|scratch| {
            scratch
                .chain_head()
                .unwrap_or_else(|| self.persisted_chain_head())
        })?)
    }

    #[allow(clippy::len_without_is_empty)]
    pub fn len(&self) -> SourceChainResult<u32> {
        Ok(self.scratch.apply(|scratch| {
            let scratch_max = scratch.chain_head().map(|(_, s, _)| s);
            scratch_max
                .map(|s| std::cmp::max(s, self.persisted_seq))
                .unwrap_or(self.persisted_seq)
                + 1
        })?)
    }
    pub async fn valid_cap_grant(
        &self,
        check_function: GrantedFunction,
        check_agent: AgentPubKey,
        check_secret: Option<CapSecret>,
    ) -> SourceChainResult<Option<CapGrant>> {
        let author_grant = CapGrant::from(self.agent_pubkey().clone());
        if author_grant.is_valid(&check_function, &check_agent, check_secret.as_ref()) {
            return Ok(Some(author_grant));
        }
        let author = self.author.clone();
        // TODO: SQL_PERF: This query could have a fast upper bound if we add indexes.
        let valid_cap_grant = self
            .vault
            .async_reader(move |txn| {
                let not_referenced_header = "
            SELECT COUNT(H_REF.hash)
            FROM Header AS H_REF
            JOIN DhtOp AS D_REF ON D_REF.header_hash = H_REF.hash
            WHERE
            H_REF.author = :author
            AND
            (H_REF.original_header_hash = Header.hash
            OR
            H_REF.deletes_header_hash = Header.hash)
            ";
                let sql = format!(
                    "
                SELECT DISTINCT Entry.blob
                FROM Entry
                JOIN Header ON Header.entry_hash = Entry.hash
                JOIN DhtOp ON Header.hash = DhtOp.header_hash
                WHERE
                Header.author = :author
                AND
                Entry.access_type IS NOT NULL
                AND
                ({}) = 0
                ",
                    not_referenced_header
                );
                txn.prepare(&sql)?
                    .query_and_then(
                        named_params! {
                            ":author": author,
                        },
                        |row| from_blob(row.get("blob")?),
                    )?
                    .filter_map(|result: StateQueryResult<Entry>| match result {
                        Ok(entry) => entry
                            .as_cap_grant()
                            .filter(|grant| !matches!(grant, CapGrant::ChainAuthor(_)))
                            .filter(|grant| {
                                grant.is_valid(&check_function, &check_agent, check_secret.as_ref())
                            })
                            .map(|cap| Some(Ok(cap)))
                            .unwrap_or(None),
                        Err(e) => Some(Err(e)),
                    })
                    // if there are still multiple grants, fold them down based on specificity
                    // authorship > assigned > transferable > unrestricted
                    .fold(
                        Ok(None),
                        |acc: StateQueryResult<Option<CapGrant>>, grant| {
                            let grant = grant?;
                            let acc = acc?;
                            let acc = match &grant {
                                CapGrant::RemoteAgent(zome_call_cap_grant) => {
                                    match &zome_call_cap_grant.access {
                                        CapAccess::Assigned { .. } => match &acc {
                                            Some(CapGrant::RemoteAgent(
                                                acc_zome_call_cap_grant,
                                            )) => {
                                                match acc_zome_call_cap_grant.access {
                                                    // an assigned acc takes precedence
                                                    CapAccess::Assigned { .. } => acc,
                                                    // current grant takes precedence over all other accs
                                                    _ => Some(grant),
                                                }
                                            }
                                            None => Some(grant),
                                            // authorship should be short circuit and filtered
                                            _ => unreachable!(),
                                        },
                                        CapAccess::Transferable { .. } => match &acc {
                                            Some(CapGrant::RemoteAgent(
                                                acc_zome_call_cap_grant,
                                            )) => {
                                                match acc_zome_call_cap_grant.access {
                                                    // an assigned acc takes precedence
                                                    CapAccess::Assigned { .. } => acc,
                                                    // transferable acc takes precedence
                                                    CapAccess::Transferable { .. } => acc,
                                                    // current grant takes preference over other accs
                                                    _ => Some(grant),
                                                }
                                            }
                                            None => Some(grant),
                                            // authorship should be short circuited and filtered by now
                                            _ => unreachable!(),
                                        },
                                        CapAccess::Unrestricted => match acc {
                                            Some(_) => acc,
                                            None => Some(grant),
                                        },
                                    }
                                }
                                // ChainAuthor should have short circuited and be filtered out already
                                _ => unreachable!(),
                            };
                            Ok(acc)
                        },
                    )
            })
            .await?;
        Ok(valid_cap_grant)
    }

    /// Query Headers in the source chain.
    /// This returns a Vec rather than an iterator because it is intended to be
    /// used by the `query` host function, which crosses the wasm boundary
    // FIXME: This query needs to be tested.
    pub async fn query(&self, query: QueryFilter) -> SourceChainResult<Vec<Element>> {
        let author = self.author.clone();
        let public_only = self.public_only;
        let mut elements = self
            .vault
            .async_reader({
                let query = query.clone();
                move |txn| {
                    let mut sql = "
                SELECT DISTINCT
                Header.hash AS header_hash, Header.blob AS header_blob
            "
                    .to_string();
                    if query.include_entries {
                        sql.push_str(
                            "
                    , Entry.blob AS entry_blob
                    ",
                        );
                    }
                    sql.push_str(
                        "
                FROM Header
                ",
                    );
                    if query.include_entries {
                        sql.push_str(
                            "
                    LEFT JOIN Entry On Header.entry_hash = Entry.hash
                    ",
                        );
                    }
                    sql.push_str(
                        "
                JOIN DhtOp On DhtOp.header_hash = Header.hash
                WHERE
                Header.author = :author
                AND
                (:range_start IS NULL AND :range_end IS NULL AND :range_start_hash IS NULL AND :range_end_hash IS NULL AND :range_prior_count IS NULL)
                ",
                    );
                    sql.push_str(match query.sequence_range {
                        ChainQueryFilterRange::Unbounded => "",
                        ChainQueryFilterRange::HeaderSeqRange(_, _) => "
                        OR (Header.seq BETWEEN :range_start AND :range_end)",
                        ChainQueryFilterRange::HeaderHashRange(_, _) => "
                        OR (
                            Header.seq BETWEEN
                            (SELECT Header.seq WHERE Header.hash = :range_start_hash)
                            AND
                            (SELECT Header.seq WHERE Header.hash = :range_end_hash)
                        )",
                        ChainQueryFilterRange::HeaderHashTerminated(_, _) => "
                        OR (
                            Header.seq BETWEEN
                            (SELECT Header.seq WHERE Header.hash = :range_end_hash) - :range_prior_count
                            AND
                            (SELECT Header.seq WHERE Header.hash = :range_end_hash)
                        )",
                    });
                    sql.push_str(
                        "
                AND
                (:entry_type IS NULL OR Header.entry_type = :entry_type)
                AND
                (:header_type IS NULL OR Header.type = :header_type)
                ORDER BY Header.seq ASC
                ",
                    );
                    let mut stmt = txn.prepare(&sql)?;
                    let elements = stmt
                        .query_and_then(
                        named_params! {
                                ":author": author.as_ref(),
                                ":entry_type": query.entry_type,
                                ":header_type": query.header_type,
                                ":range_start": match query.sequence_range {
                                    ChainQueryFilterRange::HeaderSeqRange(start, _) => Some(start),
                                    _ => None,
                                },
                                ":range_end": match query.sequence_range {
                                    ChainQueryFilterRange::HeaderSeqRange(_, end) => Some(end),
                                    _ => None,
                                },
                                ":range_start_hash": match &query.sequence_range {
                                    ChainQueryFilterRange::HeaderHashRange(start_hash, _) => Some(start_hash.clone()),
                                    _ => None,
                                },
                                ":range_end_hash": match &query.sequence_range {
                                    ChainQueryFilterRange::HeaderHashRange(_, end_hash)
                                    | ChainQueryFilterRange::HeaderHashTerminated(end_hash, _) => Some(end_hash.clone()),
                                    _ => None,
                                },
                                ":range_prior_count": match query.sequence_range {
                                    ChainQueryFilterRange::HeaderHashTerminated(_, prior_count) => Some(prior_count),
                                    _ => None,
                                },
                            },
                            |row| {
                                let header = from_blob::<SignedHeader>(row.get("header_blob")?)?;
                                let SignedHeader(header, signature) = header;
                                let private_entry = header
                                    .entry_type()
                                    .map_or(false, |e| *e.visibility() == EntryVisibility::Private);
                                let hash: HeaderHash = row.get("header_hash")?;
                                let header = HeaderHashed::with_pre_hashed(header, hash);
                                let shh = SignedHeaderHashed::with_presigned(header, signature);
                                let entry =
                                    if query.include_entries && (!private_entry || !public_only) {
                                        let entry: Option<Vec<u8>> = row.get("entry_blob")?;
                                        match entry {
                                            Some(entry) => Some(from_blob::<Entry>(entry)?),
                                            None => None,
                                        }
                                    } else {
                                        None
                                    };
                                StateQueryResult::Ok(Element::new(shh, entry))
                            },
                        )?
                        .collect::<StateQueryResult<Vec<_>>>();
                    elements
                }
            })
            .await?;
        self.scratch.apply(|scratch| {
            let mut scratch_elements: Vec<_> = scratch
                .headers()
                .filter_map(|shh| {
                    let entry = match shh.header().entry_hash() {
                        Some(eh) if query.include_entries => scratch.get_entry(eh).ok()?,
                        _ => None,
                    };
                    Some(Element::new(shh.clone(), entry))
                })
                .collect();
            scratch_elements.sort_unstable_by_key(|e| e.header().header_seq());

            elements.extend(scratch_elements);
        })?;
        Ok(query.filter_elements(elements))
    }

    pub async fn is_chain_locked(&self, lock: Vec<u8>) -> SourceChainResult<bool> {
        let author = self.author.clone();
        Ok(self
            .vault
            .async_reader(move |txn| is_chain_locked(&txn, &lock, author.as_ref()))
            .await?)
    }

    /// If there is a countersigning session get the
    /// StoreEntry op to send to the entry authorities.
    pub fn countersigning_op(&self) -> SourceChainResult<Option<DhtOp>> {
        let r = self.scratch.apply(|scratch| {
            scratch
                .entries()
                .find(|e| matches!(**e.1, Entry::CounterSign(_, _)))
                .and_then(|(entry_hash, entry)| {
                    scratch
                        .headers()
                        .find(|shh| {
                            shh.header()
                                .entry_hash()
                                .map(|eh| eh == entry_hash)
                                .unwrap_or(false)
                        })
                        .and_then(|shh| {
                            Some(DhtOp::StoreEntry(
                                shh.signature().clone(),
                                shh.header().clone().try_into().ok()?,
                                Box::new((**entry).clone()),
                            ))
                        })
                })
        })?;
        Ok(r)
    }
}

pub fn lock_for_entry(entry: Option<&Entry>) -> SourceChainResult<Vec<u8>> {
    Ok(match entry {
        Some(Entry::CounterSign(session_data, _)) => holo_hash::encode::blake2b_256(
            &holochain_serialized_bytes::encode(session_data.preflight_request())?,
        ),
        _ => Vec::with_capacity(0),
    })
}

#[allow(clippy::complexity)]
fn build_ops_from_headers(
    zomed_headers: Vec<(Option<Zome>, SignedHeaderHashed)>,
) -> SourceChainResult<(
    Vec<(Option<Zome>, SignedHeaderHashed)>,
    Vec<(DhtOpLight, DhtOpHash, OpOrder, Timestamp, Dependency)>,
)> {
    // Headers end up back in here.
    let mut headers_output = Vec::with_capacity(zomed_headers.len());
    // The op related data ends up here.
    let mut ops = Vec::with_capacity(zomed_headers.len());

    // Loop through each header and produce op related data.
    for (zome, shh) in zomed_headers {
        // &HeaderHash, &Header, EntryHash are needed to produce the ops.
        let entry_hash = shh.header().entry_hash().cloned();
        let item = (shh.as_hash(), shh.header(), entry_hash);
        let ops_inner = produce_op_lights_from_iter(vec![item].into_iter(), 1)?;

        // Break apart the SignedHeaderHashed.
        let (header, sig) = shh.into_header_and_signature();
        let (header, hash) = header.into_inner();

        // We need to take the header by value and put it back each loop.
        let mut h = Some(header);
        for op in ops_inner {
            let op_type = op.get_type();
            // Header is required by value to produce the DhtOpHash.
            let (header, op_hash) = UniqueForm::op_hash(op_type, h.expect("This can't be empty"))?;
            let op_order = OpOrder::new(op_type, header.timestamp());
            let timestamp = header.timestamp();
            // Put the header back by value.
            let dependency = get_dependency(op_type, &header);
            h = Some(header);
            // Collect the DhtOpLight, DhtOpHash and OpOrder.
            ops.push((op, op_hash, op_order, timestamp, dependency));
        }

        // Put the SignedHeaderHashed back together.
        let shh = SignedHeaderHashed::with_presigned(
            HeaderHashed::with_pre_hashed(h.expect("This can't be empty"), hash),
            sig,
        );
        // Put the header back in the list.
        headers_output.push((zome, shh));
    }
    Ok((headers_output, ops))
}

async fn rebase_headers_on(
    keystore: &MetaLairClient,
    mut zomed_headers: Vec<(Option<Zome>, SignedHeaderHashed)>,
    mut rebase_header: HeaderHash,
    mut rebase_seq: u32,
    mut rebase_timestamp: Timestamp,
) -> Result<Vec<(Option<Zome>, SignedHeaderHashed)>, ScratchError> {
    zomed_headers.sort_by_key(|(_zome, shh)| shh.header().header_seq());
    for (_zome, shh) in zomed_headers.iter_mut() {
        let mut header = shh.header().clone();
        header.rebase_on(rebase_header.clone(), rebase_seq, rebase_timestamp)?;
        rebase_seq = header.header_seq();
        rebase_timestamp = header.timestamp();
        let hh = HeaderHashed::from_content_sync(header);
        rebase_header = hh.as_hash().clone();
        let new_shh = SignedHeaderHashed::new(keystore, hh).await?;
        *shh = new_shh;
    }
    Ok(zomed_headers)
}

pub async fn genesis(
    authored: DbWrite<DbKindAuthored>,
    dht_env: DbWrite<DbKindDht>,
    keystore: MetaLairClient,
    dna_hash: DnaHash,
    agent_pubkey: AgentPubKey,
    membrane_proof: Option<SerializedBytes>,
) -> SourceChainResult<()> {
    let dna_header = Header::Dna(header::Dna {
        author: agent_pubkey.clone(),
        timestamp: Timestamp::now(),
        hash: dna_hash,
    });
    let dna_header = HeaderHashed::from_content_sync(dna_header);
    let dna_header = SignedHeaderHashed::new(&keystore, dna_header).await?;
    let dna_header_address = dna_header.as_hash().clone();
    let element = Element::new(dna_header, None);
    let dna_ops = produce_op_lights_from_elements(vec![&element])?;
    let (dna_header, _) = element.into_inner();

    // create the agent validation entry and add it directly to the store
    let agent_validation_header = Header::AgentValidationPkg(header::AgentValidationPkg {
        author: agent_pubkey.clone(),
        timestamp: Timestamp::now(),
        header_seq: 1,
        prev_header: dna_header_address,
        membrane_proof,
    });
    let agent_validation_header = HeaderHashed::from_content_sync(agent_validation_header);
    let agent_validation_header =
        SignedHeaderHashed::new(&keystore, agent_validation_header).await?;
    let avh_addr = agent_validation_header.as_hash().clone();
    let element = Element::new(agent_validation_header, None);
    let avh_ops = produce_op_lights_from_elements(vec![&element])?;
    let (agent_validation_header, _) = element.into_inner();

    // create a agent chain element and add it directly to the store
    let agent_header = Header::Create(header::Create {
        author: agent_pubkey.clone(),
        timestamp: Timestamp::now(),
        header_seq: 2,
        prev_header: avh_addr,
        entry_type: header::EntryType::AgentPubKey,
        entry_hash: agent_pubkey.clone().into(),
    });
    let agent_header = HeaderHashed::from_content_sync(agent_header);
    let agent_header = SignedHeaderHashed::new(&keystore, agent_header).await?;
    let element = Element::new(agent_header, Some(Entry::Agent(agent_pubkey)));
    let agent_ops = produce_op_lights_from_elements(vec![&element])?;
    let (agent_header, agent_entry) = element.into_inner();
    let agent_entry = agent_entry.into_option();

    let mut ops_to_integrate = Vec::new();

    let ops_to_integrate = authored
        .async_commit(move |txn| {
            ops_to_integrate.extend(source_chain::put_raw(txn, dna_header, dna_ops, None)?);
            ops_to_integrate.extend(source_chain::put_raw(
                txn,
                agent_validation_header,
                avh_ops,
                None,
            )?);
            ops_to_integrate.extend(source_chain::put_raw(
                txn,
                agent_header,
                agent_ops,
                agent_entry,
            )?);
            SourceChainResult::Ok(ops_to_integrate)
        })
        .await?;
    authored_ops_to_dht_db_without_check(ops_to_integrate, &authored, &dht_env).await?;
    Ok(())
}

pub fn put_raw(
    txn: &mut Transaction,
    shh: SignedHeaderHashed,
    ops: Vec<DhtOpLight>,
    entry: Option<Entry>,
) -> StateMutationResult<Vec<DhtOpHash>> {
    let (header, signature) = shh.into_header_and_signature();
    let (header, hash) = header.into_inner();
    let mut header = Some(header);
    let mut hashes = Vec::with_capacity(ops.len());
    let mut ops_to_integrate = Vec::with_capacity(ops.len());
    for op in &ops {
        let op_type = op.get_type();
        let (h, op_hash) =
            UniqueForm::op_hash(op_type, header.take().expect("This can't be empty"))?;
        let op_order = OpOrder::new(op_type, h.timestamp());
        let timestamp = h.timestamp();
        header = Some(h);
        hashes.push((op_hash.clone(), op_order, timestamp));
        ops_to_integrate.push(op_hash);
    }
    let shh = SignedHeaderHashed::with_presigned(
        HeaderHashed::with_pre_hashed(header.expect("This can't be empty"), hash),
        signature,
    );
    if let Some(entry) = entry {
        insert_entry(txn, EntryHashed::from_content_sync(entry))?;
    }
    insert_header(txn, shh)?;
    for (op, (op_hash, op_order, timestamp)) in ops.into_iter().zip(hashes) {
        insert_op_lite(txn, op, op_hash.clone(), op_order, timestamp)?;
    }
    Ok(ops_to_integrate)
}

/// Get the current chain head of the database.
pub fn chain_head_db(
    txn: &Transaction,
    author: Arc<AgentPubKey>,
) -> SourceChainResult<(HeaderHash, u32, Timestamp)> {
    let chain_head = ChainHeadQuery::new(author);
    let (prev_header, last_header_seq, last_header_timestamp) = chain_head
        .run(Txn::from(txn))?
        .ok_or(SourceChainError::ChainEmpty)?;
    Ok((prev_header, last_header_seq, last_header_timestamp))
}

/// Check if there is a current countersigning session and if so, return the
/// session data and the entry hash.
pub fn current_countersigning_session(
    txn: &Transaction<'_>,
    author: Arc<AgentPubKey>,
) -> SourceChainResult<Option<(EntryHash, CounterSigningSessionData)>> {
    // The chain must be locked for a session to be active.
    if is_chain_locked(txn, &[], author.as_ref())? {
        match chain_head_db(txn, author) {
            // We haven't done genesis so no session can be active.
            Err(SourceChainError::ChainEmpty) => Ok(None),
            Err(e) => Err(e),
            Ok((hash, _, _)) => {
                let txn: Txn = txn.into();
                // Get the session data from the database.
                let element = match txn.get_element(&hash.into())? {
                    Some(element) => element,
                    None => return Ok(None),
                };
                let (shh, ee) = element.into_inner();
                Ok(match (shh.header().entry_hash(), ee.into_option()) {
                    (Some(entry_hash), Some(Entry::CounterSign(cs, _))) => {
                        Some((entry_hash.to_owned(), *cs))
                    }
                    _ => None,
                })
            }
        }
    } else {
        Ok(None)
    }
}

#[cfg(test)]
async fn _put_db<H: HeaderInner, B: HeaderBuilder<H>>(
    vault: holochain_types::env::DbWrite<DbKindAuthored>,
    keystore: &MetaLairClient,
    author: Arc<AgentPubKey>,
    header_builder: B,
    maybe_entry: Option<Entry>,
) -> SourceChainResult<HeaderHash> {
    let (prev_header, last_header_seq, _) =
        fresh_reader_test!(vault, |txn| { chain_head_db(&txn, author.clone()) })?;
    let header_seq = last_header_seq + 1;

    let common = HeaderBuilderCommon {
        author: (*author).clone(),
        timestamp: Timestamp::now(),
        header_seq,
        prev_header: prev_header.clone(),
    };
    let header = header_builder.build(common).into();
    let header = HeaderHashed::from_content_sync(header);
    let header = SignedHeaderHashed::new(keystore, header).await?;
    let element = Element::new(header, maybe_entry);
    let ops = produce_op_lights_from_elements(vec![&element])?;
    let (header, entry) = element.into_inner();
    let entry = entry.into_option();
    let hash = header.as_hash().clone();
    vault.conn()?.with_commit_sync(|txn| {
        let (new_head, new_seq, new_timestamp) = chain_head_db(txn, author.clone())?;
        if new_head != prev_header {
            let entries = match (entry, header.header().entry_hash()) {
                (Some(e), Some(entry_hash)) => {
                    vec![EntryHashed::with_pre_hashed(e, entry_hash.clone())]
                }
                _ => vec![],
            };
            return Err(SourceChainError::HeadMoved(
                // Using None for the zome here because it is only used to run
                // post commit callbacks, which isn't needed here.
                vec![(None, header)],
                entries,
                Some(prev_header),
                Some((new_head, new_seq, new_timestamp)),
            ));
        }
        SourceChainResult::Ok(put_raw(txn, header, ops, entry)?)
    })?;
    Ok(hash)
}

/// dump the entire source chain as a pretty-printed json string
pub async fn dump_state(
    vault: DbRead<DbKindAuthored>,
    author: AgentPubKey,
) -> Result<SourceChainJsonDump, SourceChainError> {
    Ok(vault
        .async_reader(move |txn| {
            let elements = txn
                .prepare(
                    "
                SELECT DISTINCT
                Header.blob AS header_blob, Entry.blob AS entry_blob,
                Header.hash AS header_hash
                FROM Header
                JOIN DhtOp ON DhtOp.header_hash = Header.hash
                LEFT JOIN Entry ON Header.entry_hash = Entry.hash
                WHERE
                Header.author = :author
                ORDER BY Header.seq ASC
                ",
                )?
                .query_and_then(
                    named_params! {
                        ":author": author,
                    },
                    |row| {
                        let SignedHeader(header, signature) = from_blob(row.get("header_blob")?)?;
                        let header_address = row.get("header_hash")?;
                        let entry: Option<Vec<u8>> = row.get("entry_blob")?;
                        let entry: Option<Entry> = match entry {
                            Some(entry) => Some(from_blob(entry)?),
                            None => None,
                        };
                        StateQueryResult::Ok(SourceChainJsonElement {
                            signature,
                            header_address,
                            header,
                            entry,
                        })
                    },
                )?
                .collect::<StateQueryResult<Vec<_>>>()?;
            let published_ops_count = txn.query_row(
                "
                SELECT COUNT(DhtOp.hash) FROM DhtOp
                JOIN Header ON DhtOp.header_hash = Header.hash
                WHERE
                Header.author = :author
                AND
                last_publish_time IS NOT NULL
                ",
                named_params! {
                ":author": author,
                },
                |row| row.get(0),
            )?;
            StateQueryResult::Ok(SourceChainJsonDump {
                elements,
                published_ops_count,
            })
        })
        .await?)
}

impl From<SourceChain> for SourceChainRead {
    fn from(chain: SourceChain) -> Self {
        SourceChainRead {
            vault: chain.vault.into(),
            dht_env: chain.dht_env.into(),
            scratch: chain.scratch,
            keystore: chain.keystore,
            author: chain.author,
            persisted_seq: chain.persisted_seq,
            persisted_head: chain.persisted_head,
            persisted_timestamp: chain.persisted_timestamp,
            public_only: chain.public_only,
        }
    }
}

#[cfg(test)]
pub mod tests {
    use super::*;
    use crate::prelude::*;
    use ::fixt::prelude::*;
    use hdk::prelude::*;
    use holochain_p2p::MockHolochainP2pDnaT;
    use matches::assert_matches;

    use crate::source_chain::SourceChainResult;
    use holochain_zome_types::Entry;

    #[tokio::test(flavor = "multi_thread")]
    async fn test_relaxed_ordering() -> SourceChainResult<()> {
        let test_env = test_authored_env();
        let dht_env = test_dht_env();
        let keystore = test_keystore();
        let env = test_env.env();
        let alice = fixt!(AgentPubKey, Predictable, 0);
        let zome = fixt!(Zome);

        let mut mock = MockHolochainP2pDnaT::new();
        mock.expect_authority_for_hash().returning(|_| Ok(false));

        source_chain::genesis(
            env.clone(),
            dht_env.env(),
            keystore.clone(),
            fake_dna_hash(1),
            alice.clone(),
            None,
        )
        .await
        .unwrap();
        let chain_1 = SourceChain::new(
            env.clone().into(),
            dht_env.env(),
            keystore.clone(),
            alice.clone(),
        )
        .await?;
        let chain_2 = SourceChain::new(
            env.clone().into(),
            dht_env.env(),
            keystore.clone(),
            alice.clone(),
        )
        .await?;
        let chain_3 = SourceChain::new(
            env.clone().into(),
            dht_env.env(),
            keystore.clone(),
            alice.clone(),
        )
        .await?;

        let header_builder = builder::CloseChain {
            new_dna_hash: fixt!(DnaHash),
        };
        chain_1
            .put(
                Some(zome.clone()),
                header_builder.clone(),
                None,
                ChainTopOrdering::Strict,
            )
            .await?;
        chain_2
            .put(
                Some(zome.clone()),
                header_builder.clone(),
                None,
                ChainTopOrdering::Strict,
            )
            .await?;
        chain_3
            .put(
                Some(zome.clone()),
                header_builder,
                None,
                ChainTopOrdering::Relaxed,
            )
            .await?;

        let author = Arc::new(alice);
        chain_1.flush(&mock).await?;
        let author_1 = Arc::clone(&author);
        let (_, seq, _) = env
            .async_commit(move |txn: &mut Transaction| chain_head_db(&txn, author_1))
            .await?;
        assert_eq!(seq, 3);

        assert!(matches!(
            chain_2.flush(&mock).await,
            Err(SourceChainError::HeadMoved(_, _, _, _))
        ));
        let author_2 = Arc::clone(&author);
        let (_, seq, _) = env
            .async_commit(move |txn: &mut Transaction| chain_head_db(&txn, author_2))
            .await?;
        assert_eq!(seq, 3);

        chain_3.flush(&mock).await?;
        let author_3 = Arc::clone(&author);
        let (_, seq, _) = env
            .async_commit(move |txn: &mut Transaction| chain_head_db(&txn, author_3))
            .await?;
        assert_eq!(seq, 4);

        Ok(())
    }
    #[tokio::test(flavor = "multi_thread")]
    async fn test_relaxed_ordering_with_entry() -> SourceChainResult<()> {
        let test_env = test_authored_env();
        let dht_env = test_dht_env();
        let keystore = test_keystore();
        let env = test_env.env();
        let alice = fixt!(AgentPubKey, Predictable, 0);

        let mut mock = MockHolochainP2pDnaT::new();
        mock.expect_authority_for_hash().returning(|_| Ok(false));

        source_chain::genesis(
            env.clone(),
            dht_env.env(),
            keystore.clone(),
            fake_dna_hash(1),
            alice.clone(),
            None,
        )
        .await
        .unwrap();

        let chain_1 = SourceChain::new(
            env.clone().into(),
            dht_env.env(),
            keystore.clone(),
            alice.clone(),
        )
        .await?;
        let chain_2 = SourceChain::new(
            env.clone().into(),
            dht_env.env(),
            keystore.clone(),
            alice.clone(),
        )
        .await?;
        let chain_3 = SourceChain::new(
            env.clone().into(),
            dht_env.env(),
            keystore.clone(),
            alice.clone(),
        )
        .await?;

        let entry_1 = Entry::App(fixt!(AppEntryBytes));
        let eh1 = EntryHash::with_data_sync(&entry_1);
        let create = builder::Create {
            entry_type: EntryType::App(fixt!(AppEntryType)),
            entry_hash: eh1.clone(),
        };
        let h1 = chain_1
            .put(
                None,
                create,
                Some(entry_1.clone()),
                ChainTopOrdering::Strict,
            )
            .await
            .unwrap();

        let entry_err = Entry::App(fixt!(AppEntryBytes));
        let entry_hash_err = EntryHash::with_data_sync(&entry_err);
        let create = builder::Create {
            entry_type: EntryType::App(fixt!(AppEntryType)),
            entry_hash: entry_hash_err.clone(),
        };
        chain_2
            .put(
                None,
                create,
                Some(entry_err.clone()),
                ChainTopOrdering::Strict,
            )
            .await
            .unwrap();

        let entry_2 = Entry::App(fixt!(AppEntryBytes));
        let eh2 = EntryHash::with_data_sync(&entry_2);
        let create = builder::Create {
            entry_type: EntryType::App(AppEntryType::new(
                EntryDefIndex(0),
                fixt!(ZomeId),
                EntryVisibility::Private,
            )),
            entry_hash: eh2.clone(),
        };
        let old_h2 = chain_3
            .put(
                None,
                create,
                Some(entry_2.clone()),
                ChainTopOrdering::Relaxed,
            )
            .await
            .unwrap();

        let author = Arc::new(alice);
        chain_1.flush(&mock).await?;
        let author_1 = Arc::clone(&author);
        let (_, seq, _) = env
            .async_commit(move |txn: &mut Transaction| chain_head_db(&txn, author_1))
            .await?;
        assert_eq!(seq, 3);

        assert!(matches!(
            chain_2.flush(&mock).await,
            Err(SourceChainError::HeadMoved(_, _, _, _))
        ));

        chain_3.flush(&mock).await?;
        let author_2 = Arc::clone(&author);
        let (h2, seq, _) = env
            .async_commit(move |txn: &mut Transaction| chain_head_db(&txn, author_2.clone()))
            .await?;

        // not equal since header hash change due to rebasing
        assert_ne!(h2, old_h2);
        assert_eq!(seq, 4);

        fresh_reader_test!(env, |txn| {
            // get the full element
            let store = Txn::from(&txn);
            let h1_element_entry_fetched = store
                .get_element(&h1.clone().into())
                .expect("error retrieving")
                .expect("entry not found")
                .into_inner()
                .1;
            let h2_element_entry_fetched = store
                .get_element(&h2.clone().into())
                .expect("error retrieving")
                .expect("entry not found")
                .into_inner()
                .1;
            assert_eq!(ElementEntry::Present(entry_1), h1_element_entry_fetched);
            assert_eq!(ElementEntry::Present(entry_2), h2_element_entry_fetched);
        });

        Ok(())
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn test_get_cap_grant() -> SourceChainResult<()> {
        let test_env = test_authored_env();
        let dht_env = test_dht_env();
        let keystore = test_keystore();
        let env = test_env.env();
        let secret = Some(CapSecretFixturator::new(Unpredictable).next().unwrap());
        let access = CapAccess::from(secret.unwrap());
        let mut mock = MockHolochainP2pDnaT::new();
        let zome = fixt!(Zome);
        mock.expect_authority_for_hash().returning(|_| Ok(false));

        // @todo curry
        let _curry = CurryPayloadsFixturator::new(Empty).next().unwrap();
        let function: GrantedFunction = ("foo".into(), "bar".into());
        let mut functions: GrantedFunctions = BTreeSet::new();
        functions.insert(function.clone());
        let grant = ZomeCallCapGrant::new("tag".into(), access.clone(), functions.clone());
        let mut agents = AgentPubKeyFixturator::new(Predictable);
        let alice = agents.next().unwrap();
        let bob = agents.next().unwrap();
        source_chain::genesis(
            env.clone(),
            dht_env.env(),
            keystore.clone(),
            fake_dna_hash(1),
            alice.clone(),
            None,
        )
        .await
        .unwrap();

        {
            let chain =
                SourceChain::new(env.clone(), dht_env.env(), keystore.clone(), alice.clone())
                    .await?;
            assert_eq!(
                chain
                    .valid_cap_grant(function.clone(), alice.clone(), secret.clone())
                    .await?,
                Some(CapGrant::ChainAuthor(alice.clone())),
            );

            // bob should not match anything as the secret hasn't been committed yet
            assert_eq!(
                chain
                    .valid_cap_grant(function.clone(), bob.clone(), secret.clone())
                    .await?,
                None
            );
        }

        let (original_header_address, original_entry_address) = {
            let chain = SourceChain::new(
                env.clone().into(),
                dht_env.env(),
                keystore.clone(),
                alice.clone(),
            )
            .await?;
            let (entry, entry_hash) =
                EntryHashed::from_content_sync(Entry::CapGrant(grant.clone())).into_inner();
            let header_builder = builder::Create {
                entry_type: EntryType::CapGrant,
                entry_hash: entry_hash.clone(),
            };
            let header = chain
                .put(
                    Some(zome.clone()),
                    header_builder,
                    Some(entry),
                    ChainTopOrdering::default(),
                )
                .await?;

            chain.flush(&mock).await.unwrap();

            (header, entry_hash)
        };

        {
            let chain =
                SourceChain::new(env.clone(), dht_env.env(), keystore.clone(), alice.clone())
                    .await?;
            // alice should find her own authorship with higher priority than the committed grant
            // even if she passes in the secret
            assert_eq!(
                chain
                    .valid_cap_grant(function.clone(), alice.clone(), secret.clone())
                    .await?,
                Some(CapGrant::ChainAuthor(alice.clone())),
            );

            // bob should be granted with the committed grant as it matches the secret he passes to
            // alice at runtime
            assert_eq!(
                chain
                    .valid_cap_grant(function.clone(), bob.clone(), secret.clone())
                    .await?,
                Some(grant.clone().into())
            );
        }

        // let's roll the secret and assign the grant to bob specifically
        let mut assignees = BTreeSet::new();
        assignees.insert(bob.clone());
        let updated_secret = Some(CapSecretFixturator::new(Unpredictable).next().unwrap());
        let updated_access = CapAccess::from((updated_secret.clone().unwrap(), assignees));
        let updated_grant = ZomeCallCapGrant::new("tag".into(), updated_access.clone(), functions);

        let (updated_header_hash, updated_entry_hash) = {
            let chain = SourceChain::new(
                env.clone().into(),
                dht_env.env(),
                keystore.clone(),
                alice.clone(),
            )
            .await?;
            let (entry, entry_hash) =
                EntryHashed::from_content_sync(Entry::CapGrant(updated_grant.clone())).into_inner();
            let header_builder = builder::Update {
                entry_type: EntryType::CapGrant,
                entry_hash: entry_hash.clone(),
                original_header_address,
                original_entry_address,
            };
            let header = chain
                .put(
                    Some(zome.clone()),
                    header_builder,
                    Some(entry),
                    ChainTopOrdering::default(),
                )
                .await?;

            chain.flush(&mock).await.unwrap();

            (header, entry_hash)
        };

        {
            let chain =
                SourceChain::new(env.clone(), dht_env.env(), keystore.clone(), alice.clone())
                    .await?;
            // alice should find her own authorship with higher priority than the committed grant
            // even if she passes in the secret
            assert_eq!(
                chain
                    .valid_cap_grant(function.clone(), alice.clone(), secret.clone())
                    .await?,
                Some(CapGrant::ChainAuthor(alice.clone())),
            );
            assert_eq!(
                chain
                    .valid_cap_grant(function.clone(), alice.clone(), updated_secret.clone())
                    .await?,
                Some(CapGrant::ChainAuthor(alice.clone())),
            );

            // bob MUST provide the updated secret as the old one is invalidated by the new one
            assert_eq!(
                chain
                    .valid_cap_grant(function.clone(), bob.clone(), secret.clone())
                    .await?,
                None
            );
            assert_eq!(
                chain
                    .valid_cap_grant(function.clone(), bob.clone(), updated_secret.clone())
                    .await?,
                Some(updated_grant.into())
            );
        }

        {
            let chain = SourceChain::new(
                env.clone().into(),
                dht_env.env(),
                keystore.clone(),
                alice.clone(),
            )
            .await?;
            let header_builder = builder::Delete {
                deletes_address: updated_header_hash,
                deletes_entry_address: updated_entry_hash,
            };
            chain
                .put(
                    Some(zome),
                    header_builder,
                    None,
                    ChainTopOrdering::default(),
                )
                .await?;

            chain.flush(&mock).await.unwrap();
        }

        {
            let chain =
                SourceChain::new(env.clone(), dht_env.env(), keystore.clone(), alice.clone())
                    .await?;
            // alice should find her own authorship
            assert_eq!(
                chain
                    .valid_cap_grant(function.clone(), alice.clone(), secret.clone())
                    .await?,
                Some(CapGrant::ChainAuthor(alice.clone())),
            );
            assert_eq!(
                chain
                    .valid_cap_grant(function.clone(), alice.clone(), updated_secret.clone())
                    .await?,
                Some(CapGrant::ChainAuthor(alice)),
            );

            // bob has no access
            assert_eq!(
                chain
                    .valid_cap_grant(function.clone(), bob.clone(), secret.clone())
                    .await?,
                None
            );
            assert_eq!(
                chain
                    .valid_cap_grant(function.clone(), bob.clone(), updated_secret.clone())
                    .await?,
                None
            );
        }

        Ok(())
    }

    // @todo bring all this back when we want to administer cap claims better
    // #[tokio::test(flavor = "multi_thread")]
    // async fn test_get_cap_claim() -> SourceChainResult<()> {
    //     let test_env = test_cell_env();
    //     let env = test_env.env();
    //     let env = env.conn().unwrap().await;
    //     let secret = CapSecretFixturator::new(Unpredictable).next().unwrap();
    //     let agent_pubkey = fake_agent_pubkey_1().into();
    //     let claim = CapClaim::new("tag".into(), agent_pubkey, secret.clone());
    //     {
    //         let mut store = SourceChainBuf::new(env.clone().into(), &env).await?;
    //         store
    //             .genesis(fake_dna_hash(1), fake_agent_pubkey_1(), None)
    //             .await?;
    //         arc.conn().unwrap().with_commit(|writer| store.flush_to_txn(writer))?;
    //     }
    //
    //     {
    //         let mut chain = SourceChain::new(env.clone().into(), &env).await?;
    //         chain.put_cap_claim(claim.clone()).await?;
    //
    // // ideally the following would work, but it won't because currently
    // // we can't get claims from the scratch space
    // // this will be fixed once we add the capability index
    //
    // // assert_eq!(
    // //     chain.get_persisted_cap_claim_by_secret(&secret)?,
    // //     Some(claim.clone())
    // // );
    //
    //         arc.conn().unwrap().with_commit(|writer| chain.flush_to_txn(writer))?;
    //     }
    //
    //     {
    //         let chain = SourceChain::new(env.clone().into(), &env).await?;
    //         assert_eq!(
    //             chain.get_persisted_cap_claim_by_secret(&secret).await?,
    //             Some(claim)
    //         );
    //     }
    //
    //     Ok(())

    #[tokio::test(flavor = "multi_thread")]
    async fn source_chain_buffer_iter_back() -> SourceChainResult<()> {
        observability::test_run().ok();
        let test_env = test_authored_env();
        let dht_env = test_dht_env();
        let keystore = test_keystore();
        let vault = test_env.env();
        let mut mock = MockHolochainP2pDnaT::new();
        mock.expect_authority_for_hash().returning(|_| Ok(false));

        let author = Arc::new(keystore.new_sign_keypair_random().await.unwrap());
        let zome = fixt!(Zome);

        fresh_reader_test!(vault, |txn| {
            assert_matches!(
                chain_head_db(&txn, author.clone()),
                Err(SourceChainError::ChainEmpty)
            );
        });
        genesis(
            vault.clone().into(),
            dht_env.env(),
            keystore.clone(),
            fixt!(DnaHash),
            (*author).clone(),
            None,
        )
        .await
        .unwrap();

        let source_chain = SourceChain::new(
            vault.clone().into(),
            dht_env.env(),
            keystore.clone(),
            (*author).clone(),
        )
        .await
        .unwrap();
        let entry = Entry::App(fixt!(AppEntryBytes));
        let create = builder::Create {
            entry_type: EntryType::App(fixt!(AppEntryType)),
            entry_hash: EntryHash::with_data_sync(&entry),
        };
        let h1 = source_chain
            .put(
                Some(zome.clone()),
                create,
                Some(entry),
                ChainTopOrdering::default(),
            )
            .await
            .unwrap();
        let entry = Entry::App(fixt!(AppEntryBytes));
        let create = builder::Create {
            entry_type: EntryType::App(fixt!(AppEntryType)),
            entry_hash: EntryHash::with_data_sync(&entry),
        };
        let h2 = source_chain
            .put(Some(zome), create, Some(entry), ChainTopOrdering::default())
            .await
            .unwrap();
        source_chain.flush(&mock).await.unwrap();

        fresh_reader_test!(vault, |txn| {
            assert_eq!(chain_head_db(&txn, author.clone()).unwrap().0, h2);
            // get the full element
            let store = Txn::from(&txn);
            let h1_element_fetched = store
                .get_element(&h1.clone().into())
                .expect("error retrieving")
                .expect("entry not found");
            let h2_element_fetched = store
                .get_element(&h2.clone().into())
                .expect("error retrieving")
                .expect("entry not found");
            assert_eq!(h1, *h1_element_fetched.header_address());
            assert_eq!(h2, *h2_element_fetched.header_address());
        });

        // check that you can iterate on the chain
        let source_chain = SourceChain::new(
            vault.clone(),
            dht_env.env(),
            keystore.clone(),
            (*author).clone(),
        )
        .await
        .unwrap();
        let res = source_chain.query(QueryFilter::new()).await.unwrap();
        assert_eq!(res.len(), 5);
        assert_eq!(*res[3].header_address(), h1);
        assert_eq!(*res[4].header_address(), h2);

        Ok(())
    }

    #[tokio::test(flavor = "multi_thread")]
    async fn source_chain_buffer_dump_entries_json() -> SourceChainResult<()> {
        let test_env = test_authored_env();
        let dht_env = test_dht_env();
        let keystore = test_keystore();
        let vault = test_env.env();
        let author = keystore.new_sign_keypair_random().await.unwrap();
        genesis(
            vault.clone().into(),
            dht_env.env(),
            keystore.clone(),
            fixt!(DnaHash),
            author.clone(),
            None,
        )
        .await
        .unwrap();

        let json = dump_state(vault.clone().into(), author.clone()).await?;
        let json = serde_json::to_string_pretty(&json)?;
        let parsed: serde_json::Value = serde_json::from_str(&json).unwrap();

        assert_eq!(parsed["elements"][0]["header"]["type"], "Dna");
        assert_eq!(parsed["elements"][0]["entry"], serde_json::Value::Null);

        assert_eq!(parsed["elements"][2]["header"]["type"], "Create");
        assert_eq!(parsed["elements"][2]["header"]["entry_type"], "AgentPubKey");
        assert_eq!(parsed["elements"][2]["entry"]["entry_type"], "Agent");
        assert_ne!(
            parsed["elements"][2]["entry"]["entry"],
            serde_json::Value::Null
        );

        Ok(())
    }
}