"""Engineering entity and relationship CRUD."""

from __future__ import annotations

import json
import uuid
from dataclasses import dataclass, field
from datetime import datetime, timezone

from atocore.models.database import get_connection
from atocore.observability.logger import get_logger
from atocore.projects.registry import resolve_project_name

log = get_logger("engineering")

ENTITY_TYPES = [
    "project",
    "system",
    "subsystem",
    "component",
    "interface",
    "requirement",
    "constraint",
    "decision",
    "material",
    "parameter",
    "analysis_model",
    "result",
    "validation_claim",
    "vendor",
    "process",
]

RELATIONSHIP_TYPES = [
    # Structural family
    "contains",
    "part_of",
    "interfaces_with",
    # Intent family
    "satisfies",
    "constrained_by",
    "affected_by_decision",
    "based_on_assumption",  # Phase 5 — Q-009 killer query
    "supersedes",
    # Validation family
    "analyzed_by",
    "validated_by",
    "supports",  # Phase 5 — Q-011 killer query
    "conflicts_with",  # Phase 5 — Q-012 future
    "depends_on",
    # Provenance family
    "described_by",
    "updated_by_session",  # Phase 5 — session→entity provenance
    "evidenced_by",  # Phase 5 — Q-017 evidence trace
    "summarized_in",  # Phase 5 — mirror caches
    # Domain-specific (pre-existing, retained)
    "uses_material",
]

ENTITY_STATUSES = ["candidate", "active", "superseded", "invalid"]


@dataclass
class Entity:
    id: str
    entity_type: str
    name: str
    project: str
    description: str = ""
    properties: dict = field(default_factory=dict)
    status: str = "active"
    confidence: float = 1.0
    source_refs: list[str] = field(default_factory=list)
    created_at: str = ""
    updated_at: str = ""


@dataclass
class Relationship:
    id: str
    source_entity_id: str
    target_entity_id: str
    relationship_type: str
    confidence: float = 1.0
    source_refs: list[str] = field(default_factory=list)
    created_at: str = ""


def init_engineering_schema() -> None:
    with get_connection() as conn:
        conn.execute("""
            CREATE TABLE IF NOT EXISTS entities (
                id TEXT PRIMARY KEY,
                entity_type TEXT NOT NULL,
                name TEXT NOT NULL,
                project TEXT NOT NULL DEFAULT '',
                description TEXT NOT NULL DEFAULT '',
                properties TEXT NOT NULL DEFAULT '{}',
                status TEXT NOT NULL DEFAULT 'active',
                confidence REAL NOT NULL DEFAULT 1.0,
                source_refs TEXT NOT NULL DEFAULT '[]',
                created_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP,
                updated_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP
            )
        """)
        conn.execute("""
            CREATE TABLE IF NOT EXISTS relationships (
                id TEXT PRIMARY KEY,
                source_entity_id TEXT NOT NULL,
                target_entity_id TEXT NOT NULL,
                relationship_type TEXT NOT NULL,
                confidence REAL NOT NULL DEFAULT 1.0,
                source_refs TEXT NOT NULL DEFAULT '[]',
                created_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP,
                FOREIGN KEY (source_entity_id) REFERENCES entities(id),
                FOREIGN KEY (target_entity_id) REFERENCES entities(id)
            )
        """)
        conn.execute("""
            CREATE INDEX IF NOT EXISTS idx_entities_project
            ON entities(project)
        """)
        conn.execute("""
            CREATE INDEX IF NOT EXISTS idx_entities_type
            ON entities(entity_type)
        """)
        conn.execute("""
            CREATE INDEX IF NOT EXISTS idx_relationships_source
            ON relationships(source_entity_id)
        """)
        conn.execute("""
            CREATE INDEX IF NOT EXISTS idx_relationships_target
            ON relationships(target_entity_id)
        """)
    log.info("engineering_schema_initialized")


def create_entity(
    entity_type: str,
    name: str,
    project: str = "",
    description: str = "",
    properties: dict | None = None,
    status: str = "active",
    confidence: float = 1.0,
    source_refs: list[str] | None = None,
    actor: str = "api",
) -> Entity:
    if entity_type not in ENTITY_TYPES:
        raise ValueError(f"Invalid entity type: {entity_type}. Must be one of {ENTITY_TYPES}")
    if status not in ENTITY_STATUSES:
        raise ValueError(f"Invalid status: {status}. Must be one of {ENTITY_STATUSES}")
    if not name or not name.strip():
        raise ValueError("Entity name must be non-empty")

    # Phase 5: enforce project canonicalization contract at the write seam.
    # Aliases like "p04" become "p04-gigabit" so downstream reads stay
    # consistent with the registry.
    project = resolve_project_name(project) if project else ""

    entity_id = str(uuid.uuid4())
    now = datetime.now(timezone.utc).strftime("%Y-%m-%d %H:%M:%S")
    props = properties or {}
    refs = source_refs or []

    with get_connection() as conn:
        conn.execute(
            """INSERT INTO entities
               (id, entity_type, name, project, description, properties,
                status, confidence, source_refs, created_at, updated_at)
               VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)""",
            (
                entity_id, entity_type, name.strip(), project,
                description, json.dumps(props), status, confidence,
                json.dumps(refs), now, now,
            ),
        )

    log.info("entity_created", entity_id=entity_id, entity_type=entity_type, name=name)

    # Phase 5: entity audit rows share the memory_audit table via
    # entity_kind="entity" discriminator. Same infrastructure, unified history.
    _audit_entity(
        entity_id=entity_id,
        action="created",
        actor=actor,
        after={
            "entity_type": entity_type,
            "name": name.strip(),
            "project": project,
            "status": status,
            "confidence": confidence,
        },
    )

    return Entity(
        id=entity_id, entity_type=entity_type, name=name.strip(),
        project=project, description=description, properties=props,
        status=status, confidence=confidence, source_refs=refs,
        created_at=now, updated_at=now,
    )


def _audit_entity(
    entity_id: str,
    action: str,
    actor: str = "api",
    before: dict | None = None,
    after: dict | None = None,
    note: str = "",
) -> None:
    """Append an entity mutation row to the shared memory_audit table."""
    try:
        with get_connection() as conn:
            conn.execute(
                "INSERT INTO memory_audit (id, memory_id, action, actor, "
                "before_json, after_json, note, entity_kind) "
                "VALUES (?, ?, ?, ?, ?, ?, ?, 'entity')",
                (
                    str(uuid.uuid4()),
                    entity_id,
                    action,
                    actor or "api",
                    json.dumps(before or {}),
                    json.dumps(after or {}),
                    (note or "")[:500],
                ),
            )
    except Exception as e:
        log.warning("entity_audit_failed", entity_id=entity_id, action=action, error=str(e))


def create_relationship(
    source_entity_id: str,
    target_entity_id: str,
    relationship_type: str,
    confidence: float = 1.0,
    source_refs: list[str] | None = None,
) -> Relationship:
    if relationship_type not in RELATIONSHIP_TYPES:
        raise ValueError(f"Invalid relationship type: {relationship_type}")

    rel_id = str(uuid.uuid4())
    now = datetime.now(timezone.utc).strftime("%Y-%m-%d %H:%M:%S")
    refs = source_refs or []

    with get_connection() as conn:
        conn.execute(
            """INSERT INTO relationships
               (id, source_entity_id, target_entity_id, relationship_type,
                confidence, source_refs, created_at)
               VALUES (?, ?, ?, ?, ?, ?, ?)""",
            (rel_id, source_entity_id, target_entity_id,
             relationship_type, confidence, json.dumps(refs), now),
        )

    log.info(
        "relationship_created",
        rel_id=rel_id,
        source=source_entity_id,
        target=target_entity_id,
        rel_type=relationship_type,
    )
    # Phase 5: relationship audit as an entity action on the source
    _audit_entity(
        entity_id=source_entity_id,
        action="relationship_added",
        actor="api",
        after={
            "rel_id": rel_id,
            "rel_type": relationship_type,
            "target": target_entity_id,
        },
    )
    return Relationship(
        id=rel_id, source_entity_id=source_entity_id,
        target_entity_id=target_entity_id,
        relationship_type=relationship_type,
        confidence=confidence, source_refs=refs, created_at=now,
    )


# --- Phase 5: Entity promote/reject lifecycle ---


def _set_entity_status(
    entity_id: str,
    new_status: str,
    actor: str = "api",
    note: str = "",
) -> bool:
    """Transition an entity's status with audit."""
    if new_status not in ENTITY_STATUSES:
        raise ValueError(f"Invalid status: {new_status}")

    with get_connection() as conn:
        row = conn.execute(
            "SELECT status FROM entities WHERE id = ?", (entity_id,)
        ).fetchone()
        if row is None:
            return False
        old_status = row["status"]
        if old_status == new_status:
            return False
        now = datetime.now(timezone.utc).strftime("%Y-%m-%d %H:%M:%S")
        conn.execute(
            "UPDATE entities SET status = ?, updated_at = ? WHERE id = ?",
            (new_status, now, entity_id),
        )

    # Action verb mirrors memory pattern
    if new_status == "active" and old_status == "candidate":
        action = "promoted"
    elif new_status == "invalid" and old_status == "candidate":
        action = "rejected"
    elif new_status == "invalid":
        action = "invalidated"
    elif new_status == "superseded":
        action = "superseded"
    else:
        action = "status_changed"

    _audit_entity(
        entity_id=entity_id,
        action=action,
        actor=actor,
        before={"status": old_status},
        after={"status": new_status},
        note=note,
    )
    log.info("entity_status_changed", entity_id=entity_id,
             old=old_status, new=new_status, action=action)
    return True


def promote_entity(entity_id: str, actor: str = "api", note: str = "") -> bool:
    """Promote a candidate entity to active.

    Phase 5F graduation hook: if this entity has source_refs pointing at
    memories (format "memory:<uuid>"), mark those source memories as
    ``status=graduated`` and set their ``graduated_to_entity_id`` forward
    pointer. This preserves the memory as an immutable historical record
    while signalling that it's been absorbed into the typed graph.
    """
    entity = get_entity(entity_id)
    if entity is None or entity.status != "candidate":
        return False

    ok = _set_entity_status(entity_id, "active", actor=actor, note=note)
    if not ok:
        return False

    # Phase 5F: mark source memories as graduated
    memory_ids = [
        ref.split(":", 1)[1]
        for ref in (entity.source_refs or [])
        if isinstance(ref, str) and ref.startswith("memory:")
    ]
    if memory_ids:
        _graduate_source_memories(memory_ids, entity_id, actor=actor)

    # Phase 5G: sync conflict detection on promote. Fail-open — detection
    # errors log but never undo the successful promote.
    try:
        from atocore.engineering.conflicts import detect_conflicts_for_entity
        detect_conflicts_for_entity(entity_id)
    except Exception as e:
        log.warning("conflict_detection_failed", entity_id=entity_id, error=str(e))

    return True


def _graduate_source_memories(memory_ids: list[str], entity_id: str, actor: str) -> None:
    """Mark source memories as graduated and set forward pointer."""
    if not memory_ids:
        return
    now = datetime.now(timezone.utc).strftime("%Y-%m-%d %H:%M:%S")
    with get_connection() as conn:
        for mid in memory_ids:
            try:
                row = conn.execute(
                    "SELECT status FROM memories WHERE id = ?", (mid,)
                ).fetchone()
                if row is None:
                    continue
                old_status = row["status"]
                if old_status == "graduated":
                    continue  # already graduated — maybe by a different entity
                conn.execute(
                    "UPDATE memories SET status = 'graduated', "
                    "graduated_to_entity_id = ?, updated_at = ? WHERE id = ?",
                    (entity_id, now, mid),
                )
                # Write a memory_audit row for the graduation
                conn.execute(
                    "INSERT INTO memory_audit (id, memory_id, action, actor, "
                    "before_json, after_json, note, entity_kind) "
                    "VALUES (?, ?, 'graduated', ?, ?, ?, ?, 'memory')",
                    (
                        str(uuid.uuid4()),
                        mid,
                        actor or "api",
                        json.dumps({"status": old_status}),
                        json.dumps({
                            "status": "graduated",
                            "graduated_to_entity_id": entity_id,
                        }),
                        f"graduated to entity {entity_id[:8]}",
                    ),
                )
                log.info("memory_graduated", memory_id=mid,
                         entity_id=entity_id, old_status=old_status)
            except Exception as e:
                log.warning("memory_graduation_failed",
                            memory_id=mid, entity_id=entity_id, error=str(e))


def reject_entity_candidate(entity_id: str, actor: str = "api", note: str = "") -> bool:
    """Reject a candidate entity (status → invalid)."""
    with get_connection() as conn:
        row = conn.execute(
            "SELECT status FROM entities WHERE id = ?", (entity_id,)
        ).fetchone()
    if row is None or row["status"] != "candidate":
        return False
    return _set_entity_status(entity_id, "invalid", actor=actor, note=note)


def supersede_entity(entity_id: str, actor: str = "api", note: str = "") -> bool:
    """Mark an active entity as superseded by a newer one."""
    return _set_entity_status(entity_id, "superseded", actor=actor, note=note)


def get_entity_audit(entity_id: str, limit: int = 100) -> list[dict]:
    """Fetch audit entries for an entity from the shared audit table."""
    with get_connection() as conn:
        rows = conn.execute(
            "SELECT id, memory_id AS entity_id, action, actor, before_json, "
            "after_json, note, timestamp FROM memory_audit "
            "WHERE entity_kind = 'entity' AND memory_id = ? "
            "ORDER BY timestamp DESC LIMIT ?",
            (entity_id, limit),
        ).fetchall()
    out = []
    for r in rows:
        try:
            before = json.loads(r["before_json"] or "{}")
        except Exception:
            before = {}
        try:
            after = json.loads(r["after_json"] or "{}")
        except Exception:
            after = {}
        out.append({
            "id": r["id"],
            "entity_id": r["entity_id"],
            "action": r["action"],
            "actor": r["actor"] or "api",
            "before": before,
            "after": after,
            "note": r["note"] or "",
            "timestamp": r["timestamp"],
        })
    return out


def get_entities(
    entity_type: str | None = None,
    project: str | None = None,
    status: str = "active",
    name_contains: str | None = None,
    limit: int = 100,
) -> list[Entity]:
    query = "SELECT * FROM entities WHERE status = ?"
    params: list = [status]

    if entity_type:
        query += " AND entity_type = ?"
        params.append(entity_type)
    if project is not None:
        query += " AND project = ?"
        params.append(project)
    if name_contains:
        query += " AND name LIKE ?"
        params.append(f"%{name_contains}%")

    query += " ORDER BY entity_type, name LIMIT ?"
    params.append(min(limit, 500))

    with get_connection() as conn:
        rows = conn.execute(query, params).fetchall()
    return [_row_to_entity(r) for r in rows]


def get_entity(entity_id: str) -> Entity | None:
    with get_connection() as conn:
        row = conn.execute(
            "SELECT * FROM entities WHERE id = ?", (entity_id,)
        ).fetchone()
    if row is None:
        return None
    return _row_to_entity(row)


def get_relationships(
    entity_id: str,
    direction: str = "both",
) -> list[Relationship]:
    results = []
    with get_connection() as conn:
        if direction in ("outgoing", "both"):
            rows = conn.execute(
                "SELECT * FROM relationships WHERE source_entity_id = ?",
                (entity_id,),
            ).fetchall()
            results.extend(_row_to_relationship(r) for r in rows)
        if direction in ("incoming", "both"):
            rows = conn.execute(
                "SELECT * FROM relationships WHERE target_entity_id = ?",
                (entity_id,),
            ).fetchall()
            results.extend(_row_to_relationship(r) for r in rows)
    return results


def get_entity_with_context(entity_id: str) -> dict | None:
    entity = get_entity(entity_id)
    if entity is None:
        return None
    relationships = get_relationships(entity_id)
    related_ids = set()
    for rel in relationships:
        related_ids.add(rel.source_entity_id)
        related_ids.add(rel.target_entity_id)
    related_ids.discard(entity_id)

    related_entities = {}
    for rid in related_ids:
        e = get_entity(rid)
        if e:
            related_entities[rid] = e

    return {
        "entity": entity,
        "relationships": relationships,
        "related_entities": related_entities,
    }


def _row_to_entity(row) -> Entity:
    return Entity(
        id=row["id"],
        entity_type=row["entity_type"],
        name=row["name"],
        project=row["project"] or "",
        description=row["description"] or "",
        properties=json.loads(row["properties"] or "{}"),
        status=row["status"],
        confidence=row["confidence"],
        source_refs=json.loads(row["source_refs"] or "[]"),
        created_at=row["created_at"] or "",
        updated_at=row["updated_at"] or "",
    )


def _row_to_relationship(row) -> Relationship:
    return Relationship(
        id=row["id"],
        source_entity_id=row["source_entity_id"],
        target_entity_id=row["target_entity_id"],
        relationship_type=row["relationship_type"],
        confidence=row["confidence"],
        source_refs=json.loads(row["source_refs"] or "[]"),
        created_at=row["created_at"] or "",
    )