//! CLI-side wire-schema wrappers.
//!
//! Convention (per design §2): every JSON object emitted on stdout in
//! `--json` mode MUST carry a top-level `schema_version` of the form
//! `"<object>.v1"`. The kb-core types are pure domain types and do NOT
//! carry `schema_version` themselves; the CLI wraps them on emit. The one
//! exception is `DoctorReport`, where `schema_version` is part of the wire
//! type because the doctor wire object IS its own structured surface.
//!
//! Future tasks (P1-5, P3, P4, P5) replacing stub `bail!` paths must call
//! these helpers from the relevant CLI subcommand handler before
//! `serde_json::to_string`.
//!
//! Each helper is total (returns `serde_json::Value`, never an error) — the
//! input is a fully-typed `serde::Serialize` value, so the only way to fail
//! is OOM, which would have killed the process anyway.

use serde_json::Value;

use kebab_app::DoctorReport;
use kebab_core::{Answer, Chunk, DocSummary, IngestReport, SearchHit};

/// Insert `schema_version` into an object-shaped `Value`. Helper for the
/// "serialize, then tag" pattern used by all the per-type wrappers below.
fn tag_object(mut v: Value, schema_version: &str) -> Value {
    if let Value::Object(ref mut map) = v {
        map.insert(
            "schema_version".to_string(),
            Value::String(schema_version.to_string()),
        );
    }
    v
}

/// Wrap an [`IngestReport`] as `ingest_report.v1`.
pub fn wire_ingest(r: &IngestReport) -> Value {
    let v = serde_json::to_value(r).expect("IngestReport serializes");
    tag_object(v, "ingest_report.v1")
}

/// Wrap a single [`DocSummary`] as `doc_summary.v1`.
pub fn wire_doc_summary(d: &DocSummary) -> Value {
    let v = serde_json::to_value(d).expect("DocSummary serializes");
    tag_object(v, "doc_summary.v1")
}

/// Wrap a list of [`DocSummary`] values as a JSON array of `doc_summary.v1`
/// objects (one tag per element, per design §2.5 — there is no list-envelope
/// schema; the list shape is `[{schema_version: "doc_summary.v1", ...}, ...]`).
pub fn wire_doc_summaries(d: &[DocSummary]) -> Value {
    Value::Array(d.iter().map(wire_doc_summary).collect())
}

/// Wrap a [`Chunk`] as `chunk_inspection.v1` (§2.6). NOTE: the wire schema
/// requires `doc_path`, which the kb-core `Chunk` does not currently carry —
/// when P1-5 wires the Ok-path, the implementation should either enrich
/// `Chunk` or pass `doc_path` alongside. For now this helper emits whatever
/// fields `Chunk` serializes with, plus the `schema_version` tag.
pub fn wire_chunk_inspection(c: &Chunk) -> Value {
    let v = serde_json::to_value(c).expect("Chunk serializes");
    tag_object(v, "chunk_inspection.v1")
}

/// Wrap a single [`SearchHit`] as `search_hit.v1`.
pub fn wire_search_hit(h: &SearchHit) -> Value {
    let mut v = serde_json::to_value(h).expect("SearchHit serializes");
    // Promote `retrieval.fusion_score` to a top-level `score` per §2.2.
    if let Value::Object(ref mut map) = v {
        if let Some(Value::Object(retrieval)) = map.get("retrieval") {
            if let Some(score) = retrieval.get("fusion_score").cloned() {
                map.insert("score".to_string(), score);
            }
        }
    }
    tag_object(v, "search_hit.v1")
}

/// Wrap a list of [`SearchHit`] values as a JSON array of `search_hit.v1`
/// objects (one tag per element, per design §2.2).
pub fn wire_search_hits(hits: &[SearchHit]) -> Value {
    Value::Array(hits.iter().map(wire_search_hit).collect())
}

/// Wrap an [`Answer`] as `answer.v1`.
pub fn wire_answer(a: &Answer) -> Value {
    let v = serde_json::to_value(a).expect("Answer serializes");
    tag_object(v, "answer.v1")
}

/// Idempotent pass-through for [`DoctorReport`] — the type already carries
/// `schema_version: "doctor.v1"` (struct-field convention, the one
/// exception called out in the module doc above). This helper exists so
/// every `--json` branch in `kb-cli` goes through `wire::*`, keeping the
/// emit pattern uniform.
pub fn wire_doctor(d: &DoctorReport) -> Value {
    // Round-trip through `to_value` to confirm the field is serialized;
    // then re-tag (no-op when the field is already present, defensive
    // when a future refactor drops the struct-field).
    let v = serde_json::to_value(d).expect("DoctorReport serializes");
    if let Value::Object(ref map) = v {
        if matches!(
            map.get("schema_version"),
            Some(Value::String(s)) if s == "doctor.v1"
        ) {
            return v;
        }
    }
    tag_object(v, "doctor.v1")
}

/// Wrap a [`kebab_app::ResetReport`] as `reset_report.v1`.
pub fn wire_reset(r: &kebab_app::ResetReport) -> Value {
    let v = serde_json::to_value(r).expect("ResetReport serializes");
    tag_object(v, "reset_report.v1")
}

/// Wrap an [`kebab_app::IngestEvent`] as `ingest_progress.v1`. Adds
/// the `schema_version` discriminator on top of serde's existing
/// `kind` discriminator, plus an `ts` field with the current
/// wall-clock — the emit site is the only place that knows the moment
/// of emission, so the timestamp is stamped here rather than carried
/// on the event itself.
pub fn wire_ingest_progress(
    event: &kebab_app::IngestEvent,
) -> anyhow::Result<Value> {
    let mut v = serde_json::to_value(event)?;
    if let Value::Object(ref mut map) = v {
        map.insert(
            "ts".to_string(),
            Value::String(crate::progress::now_rfc3339()?),
        );
    }
    Ok(tag_object(v, "ingest_progress.v1"))
}

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

    fn schema_of(v: &Value) -> Option<&str> {
        v.as_object()?.get("schema_version")?.as_str()
    }

    #[test]
    fn doctor_round_trip_preserves_schema_version() {
        let d = DoctorReport {
            schema_version: "doctor.v1".to_string(),
            ok: true,
            checks: Vec::new(),
        };
        let v = wire_doctor(&d);
        assert_eq!(schema_of(&v), Some("doctor.v1"));
        // Sanity: ok/checks are preserved.
        assert_eq!(v.get("ok").and_then(Value::as_bool), Some(true));
        assert!(v.get("checks").and_then(Value::as_array).is_some());
    }

    #[test]
    fn ingest_wrapper_tags_schema_version() {
        use kebab_core::SourceScope;
        let r = IngestReport {
            scope: SourceScope {
                root: std::path::PathBuf::from("/tmp"),
                include: vec![],
                exclude: vec![],
            },
            scanned: 0,
            new: 0,
            updated: 0,
            skipped: 0,
            errors: 0,
            duration_ms: 0,
            items: None,
        };
        let v = wire_ingest(&r);
        assert_eq!(schema_of(&v), Some("ingest_report.v1"));
        assert!(v.get("items").is_some());
    }

    #[test]
    fn doc_summaries_wraps_each_element() {
        let v = wire_doc_summaries(&[]);
        assert!(v.is_array());
        assert_eq!(v.as_array().unwrap().len(), 0);
    }

    #[test]
    fn search_hits_wraps_each_element() {
        let v = wire_search_hits(&[]);
        assert!(v.is_array());
        assert_eq!(v.as_array().unwrap().len(), 0);
    }

    #[test]
    fn tag_object_inserts_into_object() {
        let v = Value::Object(serde_json::Map::new());
        let tagged = tag_object(v, "x.v1");
        assert_eq!(schema_of(&tagged), Some("x.v1"));
    }

    #[test]
    fn reset_wrapper_tags_schema_version_and_serializes_scope() {
        let r = kebab_app::ResetReport {
            scope: kebab_app::ResetScope::DataOnly,
            removed_paths: vec![std::path::PathBuf::from("/tmp/x")],
            embedding_rows_truncated: 0,
        };
        let v = wire_reset(&r);
        assert_eq!(schema_of(&v), Some("reset_report.v1"));
        assert_eq!(v.get("scope").and_then(Value::as_str), Some("data_only"));
        assert_eq!(
            v.get("embedding_rows_truncated").and_then(Value::as_u64),
            Some(0)
        );
        let paths = v.get("removed_paths").and_then(Value::as_array).unwrap();
        assert_eq!(paths.len(), 1);
        assert_eq!(paths[0].as_str(), Some("/tmp/x"));
    }
}