hayson-binding-shared 0.6.0

use hayson_engine::catalog::{IntegrityReport, MigrateOutcome, OrphanRecord, Relation};
use hayson_engine::compaction::CompactionResult;
use hayson_engine::database::{Layout, LayoutMigrationResult};
use hayson_engine::query::{AccessPathSummary, OverlayStrategy, PlanBranch, PlanOverlay, QueryStrategy};
use hayson_engine::schema::HaysonRecord;
use hayson_engine::table::{BrokenLink, RefreshOutcome, RotationResult, TableStats};
use hayson_engine::txn::UnitOfWorkResult;
use serde_json::{json, Value};

pub fn migrate_format1_outcome_to_json(outcome: &MigrateOutcome) -> Value {
    match outcome {
        MigrateOutcome::AlreadyMigrated { catalog } => json!({
            "migrated": false,
            "catalog": catalog.display().to_string(),
            "tables": [],
            "removedSchemaFiles": [],
        }),
        MigrateOutcome::Migrated {
            catalog,
            tables,
            removed_schema_files,
        } => json!({
            "migrated": true,
            "catalog": catalog.display().to_string(),
            "tables": tables,
            "removedSchemaFiles": removed_schema_files
                .iter()
                .map(|path| path.display().to_string())
                .collect::<Vec<_>>(),
        }),
    }
}

pub fn record_to_json(record: &HaysonRecord) -> Value {
    Value::Object(
        record
            .iter()
            .map(|(field, value)| (field.clone(), value.clone()))
            .collect(),
    )
}

/// The broken markdown links of a record, as the JS side reads them: one object per link, the
/// field it sits in against the virtual path it aimed at. Structured rather than a formatted
/// sentence, so a caller can group by field or retry a target without parsing text apart.
pub fn broken_links_to_json(broken: &[BrokenLink]) -> Value {
    Value::Array(
        broken
            .iter()
            .map(|link| json!({ "field": link.field, "path": link.path }))
            .collect(),
    )
}

fn strategy_name(strategy: QueryStrategy) -> &'static str {
    match strategy {
        QueryStrategy::Primary => "primary",
        QueryStrategy::Exact => "exact",
        QueryStrategy::Sorted => "sorted",
        QueryStrategy::Fulltext => "fulltext",
        QueryStrategy::Union => "union",
        QueryStrategy::Scan => "scan",
    }
}

fn plan_branch_to_json(branch: &PlanBranch) -> Value {
    json!({
        "strategy": strategy_name(branch.strategy),
        "field": branch.field,
        "candidates": branch.candidates,
    })
}

fn overlay_strategy_name(strategy: OverlayStrategy) -> &'static str {
    match strategy {
        OverlayStrategy::Exact => "exact",
        OverlayStrategy::Fulltext => "fulltext",
        OverlayStrategy::Scan => "scan",
    }
}

fn plan_overlay_to_json(overlay: &PlanOverlay) -> Value {
    json!({
        "staged": overlay.staged,
        "suppressed": overlay.suppressed,
        "rescored": overlay.rescored,
        "strategy": overlay_strategy_name(overlay.strategy),
        "size": overlay.size,
    })
}

pub fn plan_to_json(plan: &AccessPathSummary) -> Value {
    json!({
        "strategy": strategy_name(plan.strategy),
        "field": plan.field,
        "index": plan.index,
        "candidates": plan.candidates,
        "ranked": plan.ranked,
        "filteredOnProjection": plan.filtered_on_projection,
        "reads": plan.reads,
        "branches": plan.branches.as_ref().map(|branches| branches.iter().map(plan_branch_to_json).collect::<Vec<_>>()),
        "overlay": plan.overlay.as_ref().map(plan_overlay_to_json),
    })
}

/// The whole answer to `Table.query`: the keys of the page, in query order, the records
/// themselves, how many records matched before `offset`/`limit` cut that page out of them, and the
/// plan that found them — one document rather than a bare array, so the shim can rebuild the
/// `QueryResult` the TS package already exposes without a second round trip for the plan.
pub fn query_result_to_json(
    keys: &[String],
    records: &[HaysonRecord],
    matched: usize,
    plan: &AccessPathSummary,
) -> Value {
    json!({
        "keys": keys,
        "records": records.iter().map(record_to_json).collect::<Vec<_>>(),
        "matched": matched,
        "plan": plan_to_json(plan),
    })
}

/// The answer to a `getMany`: one entry per key the caller asked for, in that order, `null` where
/// the table holds no record — so the caller can zip it against its own key list without a second
/// lookup for which key went missing.
pub fn optional_records_to_json(records: &[Option<HaysonRecord>]) -> Value {
    Value::Array(
        records
            .iter()
            .map(|record| record.as_ref().map(record_to_json).unwrap_or(Value::Null))
            .collect(),
    )
}

/// The whole answer to committing a unit of work, in the shape the TS `UnitOfWorkResult` declares.
/// `tables` is what the unit actually touched, which includes tables reached only by a trigger
/// effect and not named by any staged operation.
pub fn unit_of_work_result_to_json(result: &UnitOfWorkResult) -> Value {
    json!({ "id": result.id, "tables": result.tables, "operations": result.operations })
}

pub fn relation_to_json(relation: &Relation) -> Value {
    json!({
        "name": relation.name,
        "from": { "table": relation.from.table, "field": relation.from.field },
        "to": { "table": relation.to.table, "field": relation.to.field },
        "cardinality": relation.cardinality.as_str(),
        "onDelete": relation.on_delete.map(|action| action.as_str()),
        "enforce": relation.enforce,
    })
}

pub fn relations_to_json(relations: &[Relation]) -> Value {
    Value::Array(relations.iter().map(relation_to_json).collect())
}

fn orphan_record_to_json(orphan: &OrphanRecord) -> Value {
    json!({
        "relation": orphan.relation,
        "table": orphan.table,
        "field": orphan.field,
        "primaryKey": orphan.primary_key,
        "value": orphan.value,
    })
}

pub fn integrity_report_to_json(report: &IntegrityReport) -> Value {
    json!({ "orphans": report.orphans.iter().map(orphan_record_to_json).collect::<Vec<_>>() })
}

/// The counters of `Table.stats()`, in the member names the TS `TableStats` already uses.
/// Where a database keeps its files, in the shape of the TS `Database.layout` property — the
/// deprecated aliases (`catalogFile`/`catalog`/`manifestFile`/`manifest`) carried alongside the
/// current names, holding the same values, because the TS shim reports them all.
pub fn layout_to_json(layout: &Layout) -> Value {
    let metadata_file = layout.metadata_file();
    let metadata_path = layout.metadata_path().display().to_string();
    json!({
        "kind": layout.kind().as_str(),
        "root": layout.root().display().to_string(),
        "metadataFile": metadata_file,
        "metadataPath": metadata_path,
        "catalogFile": metadata_file,
        "catalog": metadata_path,
        "manifestFile": metadata_file,
        "manifest": metadata_path,
        "tables": layout.tables().display().to_string(),
        "indexes": layout.indexes().display().to_string(),
        "runtime": layout.runtime().display().to_string(),
        "lock": layout.lock_path().display().to_string(),
        "journal": layout.journal_path().display().to_string(),
    })
}

/// What `migrateLayout()` answers with, in the shape of the TS `LayoutMigrationResult`. Every path
/// crosses as the engine spelled it, which on the WASM binding is a path inside the module's
/// preopened namespace — the shim rewrites those into host paths, as it already does for a refusal.
pub fn layout_migration_to_json(result: &LayoutMigrationResult) -> Value {
    json!({
        "root": result.root.display().to_string(),
        "from": result.from.as_str(),
        "to": result.to.as_str(),
        "moves": result
            .moves
            .iter()
            .map(|step| json!({ "from": step.from.display().to_string(), "to": step.to.display().to_string() }))
            .collect::<Vec<_>>(),
        "unclaimed": result
            .unclaimed
            .iter()
            .map(|path| path.display().to_string())
            .collect::<Vec<_>>(),
        "changed": result.changed,
        "dryRun": result.dry_run,
    })
}

pub fn table_stats_to_json(stats: &TableStats) -> Value {
    json!({
        "records": stats.records,
        "liveBytes": stats.live_bytes,
        "deadBytes": stats.dead_bytes,
        "logBytes": stats.log_bytes,
        "queueDepth": stats.queue_depth,
        "gen": stats.gen,
        "seq": stats.seq,
    })
}

/// What a `Table.refresh()` found. `changed` is the boolean the TS `Table.refresh()` answers with;
/// `outcome` and `entries` say how it got there, which is what tells a caller apart the cheap
/// catch-up from the rebuild a foreign compaction forces.
pub fn refresh_outcome_to_json(outcome: RefreshOutcome) -> Value {
    let (name, entries) = match outcome {
        RefreshOutcome::Unchanged => ("unchanged", 0),
        RefreshOutcome::CaughtUp { entries } => ("caughtUp", entries),
        RefreshOutcome::Reloaded => ("reloaded", 0),
    };
    json!({ "changed": outcome.changed(), "outcome": name, "entries": entries })
}

/// What a `Table.rotateCypherKeys()` did — records, not fields, and the three outcomes apart, so a
/// caller can tell "nothing to do" from "a record was left behind for want of its key".
pub fn rotation_result_to_json(result: &RotationResult) -> Value {
    json!({
        "rotated": result.rotated,
        "alreadyCurrent": result.already_current,
        "skipped": result.skipped,
    })
}

// NOTE: `slots` is dropped on purpose — an internal remap detail, not a caller-facing stat.
pub fn compaction_result_to_json(result: &CompactionResult) -> Value {
    json!({
        "records": result.records,
        "bytesBefore": result.bytes_before,
        "bytesAfter": result.bytes_after,
        "reclaimedBytes": result.reclaimed_bytes,
    })
}

#[cfg(test)]
mod tests {
    use hayson_engine::catalog::{RelationCardinality, RelationEnd};

    use super::*;

    #[test]
    fn a_query_result_carries_keys_records_the_match_count_and_the_plan_in_one_document() {
        let mut record = HaysonRecord::new();
        record.insert("id".into(), json!("u1"));
        record.insert("name".into(), json!("Ania"));
        let plan = AccessPathSummary {
            strategy: QueryStrategy::Exact,
            field: Some("email".into()),
            index: Some("users_email".into()),
            candidates: 1,
            ranked: false,
            filtered_on_projection: true,
            overlay: None,
            reads: 1,
            branches: None,
        };

        let described = query_result_to_json(&["u1".to_string()], &[record], 7, &plan);

        assert_eq!(described["keys"], json!(["u1"]));
        assert_eq!(described["records"], json!([{ "id": "u1", "name": "Ania" }]));
        assert_eq!(
            described["matched"],
            json!(7),
            "the page is one key wide, the match count is not"
        );
        assert_eq!(described["plan"]["strategy"], json!("exact"));
        assert_eq!(described["plan"]["index"], json!("users_email"));
        assert_eq!(described["plan"]["branches"], Value::Null);
    }

    #[test]
    fn a_plan_carries_ranked_and_filtered_on_projection_under_the_names_the_ts_query_plan_declares() {
        let plan = AccessPathSummary {
            strategy: QueryStrategy::Fulltext,
            field: None,
            index: None,
            candidates: 2,
            ranked: true,
            filtered_on_projection: false,
            overlay: None,
            reads: 2,
            branches: None,
        };

        let described = plan_to_json(&plan);

        assert_eq!(described["ranked"], json!(true));
        assert_eq!(described["filteredOnProjection"], json!(false));
    }

    #[test]
    fn every_query_strategy_has_a_lower_case_name_the_ts_union_already_uses() {
        let all = [
            QueryStrategy::Primary,
            QueryStrategy::Exact,
            QueryStrategy::Sorted,
            QueryStrategy::Fulltext,
            QueryStrategy::Union,
            QueryStrategy::Scan,
        ];
        let names: Vec<&str> = all.into_iter().map(strategy_name).collect();

        assert_eq!(names, vec!["primary", "exact", "sorted", "fulltext", "union", "scan"]);
    }

    #[test]
    fn a_relation_is_flattened_into_the_shape_the_ts_relation_type_declares() {
        let relation = Relation {
            name: "orders_user".into(),
            from: RelationEnd {
                table: "orders".into(),
                field: "userId".into(),
            },
            to: RelationEnd {
                table: "users".into(),
                field: "id".into(),
            },
            cardinality: RelationCardinality::ManyToOne,
            on_delete: None,
            enforce: Some(true),
        };

        let described = relations_to_json(&[relation]);

        assert_eq!(described[0]["from"], json!({ "table": "orders", "field": "userId" }));
        assert_eq!(described[0]["onDelete"], Value::Null);
        assert_eq!(described[0]["enforce"], json!(true));
    }

    #[test]
    fn a_get_many_answer_keeps_a_hole_where_the_table_held_no_record() {
        let mut record = HaysonRecord::new();
        record.insert("id".into(), json!("u1"));

        let described = optional_records_to_json(&[None, Some(record), None]);

        assert_eq!(described, json!([Value::Null, { "id": "u1" }, Value::Null]));
    }

    #[test]
    fn a_committed_unit_reports_the_id_the_tables_and_how_many_operations_it_carried() {
        let result = UnitOfWorkResult {
            id: "42-1-0".into(),
            tables: vec!["users".into(), "audit".into()],
            operations: 3,
        };

        let described = unit_of_work_result_to_json(&result);

        assert_eq!(
            described,
            json!({ "id": "42-1-0", "tables": ["users", "audit"], "operations": 3 })
        );
    }

    #[test]
    fn table_stats_cross_the_boundary_under_the_camel_case_names_the_ts_type_declares() {
        let stats = TableStats {
            records: 2,
            live_bytes: 40,
            dead_bytes: 10,
            log_bytes: 50,
            queue_depth: 0,
            gen: 1,
            seq: 7,
        };

        let described = table_stats_to_json(&stats);

        assert_eq!(
            described,
            json!({ "records": 2, "liveBytes": 40, "deadBytes": 10, "logBytes": 50, "queueDepth": 0, "gen": 1, "seq": 7 })
        );
    }

    #[test]
    fn each_refresh_outcome_names_itself_and_agrees_with_its_own_changed_flag() {
        let unchanged = refresh_outcome_to_json(RefreshOutcome::Unchanged);
        let caught_up = refresh_outcome_to_json(RefreshOutcome::CaughtUp { entries: 3 });
        let reloaded = refresh_outcome_to_json(RefreshOutcome::Reloaded);

        assert_eq!(
            unchanged,
            json!({ "changed": false, "outcome": "unchanged", "entries": 0 })
        );
        assert_eq!(
            caught_up,
            json!({ "changed": true, "outcome": "caughtUp", "entries": 3 })
        );
        assert_eq!(
            reloaded,
            json!({ "changed": true, "outcome": "reloaded", "entries": 0 })
        );
    }

    #[test]
    fn a_record_keeps_its_field_order_across_the_boundary() {
        let mut record = HaysonRecord::new();
        record.insert("id".into(), json!("u1"));
        record.insert("age".into(), json!(31));

        let text = record_to_json(&record).to_string();

        assert_eq!(
            text, r#"{"age":31,"id":"u1"}"#,
            "HaysonRecord is a BTreeMap — field order is its key order"
        );
    }
}