"""Memory Core — structured memory management.

Memory types (per Master Plan):
  - identity:    who the user is, role, background
  - preference:  how they like to work, style, tools
  - project:     project-specific knowledge and context
  - episodic:    what happened, conversations, events
  - knowledge:   verified facts, technical knowledge
  - adaptation:  learned corrections, behavioral adjustments

Memories have:
  - confidence (0.0–1.0): how certain we are
  - status (active/superseded/invalid): lifecycle state
  - optional link to source chunk: traceability
"""

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

from atocore.models.database import get_connection
from atocore.observability.logger import get_logger

log = get_logger("memory")

MEMORY_TYPES = [
    "identity",
    "preference",
    "project",
    "episodic",
    "knowledge",
    "adaptation",
]


@dataclass
class Memory:
    id: str
    memory_type: str
    content: str
    project: str
    source_chunk_id: str
    confidence: float
    status: str
    created_at: str
    updated_at: str


def create_memory(
    memory_type: str,
    content: str,
    project: str = "",
    source_chunk_id: str = "",
    confidence: float = 1.0,
) -> Memory:
    """Create a new memory entry."""
    if memory_type not in MEMORY_TYPES:
        raise ValueError(f"Invalid memory type '{memory_type}'. Must be one of: {MEMORY_TYPES}")

    memory_id = str(uuid.uuid4())
    now = datetime.now(timezone.utc).isoformat()

    # Check for duplicate content within same type+project
    with get_connection() as conn:
        existing = conn.execute(
            "SELECT id FROM memories WHERE memory_type = ? AND content = ? AND status = 'active'",
            (memory_type, content),
        ).fetchone()
        if existing:
            log.info("memory_duplicate_skipped", memory_type=memory_type, content_preview=content[:80])
            return _row_to_memory(
                conn.execute("SELECT * FROM memories WHERE id = ?", (existing["id"],)).fetchone()
            )

        conn.execute(
            "INSERT INTO memories (id, memory_type, content, source_chunk_id, confidence, status) "
            "VALUES (?, ?, ?, ?, ?, 'active')",
            (memory_id, memory_type, content, source_chunk_id or None, confidence),
        )

    log.info("memory_created", memory_type=memory_type, content_preview=content[:80])

    return Memory(
        id=memory_id,
        memory_type=memory_type,
        content=content,
        project=project,
        source_chunk_id=source_chunk_id,
        confidence=confidence,
        status="active",
        created_at=now,
        updated_at=now,
    )


def get_memories(
    memory_type: str | None = None,
    active_only: bool = True,
    min_confidence: float = 0.0,
    limit: int = 50,
) -> list[Memory]:
    """Retrieve memories, optionally filtered."""
    query = "SELECT * FROM memories WHERE 1=1"
    params: list = []

    if memory_type:
        query += " AND memory_type = ?"
        params.append(memory_type)
    if active_only:
        query += " AND status = 'active'"
    if min_confidence > 0:
        query += " AND confidence >= ?"
        params.append(min_confidence)

    query += " ORDER BY confidence DESC, updated_at DESC LIMIT ?"
    params.append(limit)

    with get_connection() as conn:
        rows = conn.execute(query, params).fetchall()

    return [_row_to_memory(r) for r in rows]


def update_memory(
    memory_id: str,
    content: str | None = None,
    confidence: float | None = None,
    status: str | None = None,
) -> bool:
    """Update an existing memory."""
    updates = []
    params: list = []

    if content is not None:
        updates.append("content = ?")
        params.append(content)
    if confidence is not None:
        updates.append("confidence = ?")
        params.append(confidence)
    if status is not None:
        if status not in ("active", "superseded", "invalid"):
            raise ValueError(f"Invalid status '{status}'")
        updates.append("status = ?")
        params.append(status)

    if not updates:
        return False

    updates.append("updated_at = CURRENT_TIMESTAMP")
    params.append(memory_id)

    with get_connection() as conn:
        result = conn.execute(
            f"UPDATE memories SET {', '.join(updates)} WHERE id = ?",
            params,
        )

    if result.rowcount > 0:
        log.info("memory_updated", memory_id=memory_id)
        return True
    return False


def invalidate_memory(memory_id: str) -> bool:
    """Mark a memory as invalid (error correction)."""
    return update_memory(memory_id, status="invalid")


def supersede_memory(memory_id: str) -> bool:
    """Mark a memory as superseded (replaced by newer info)."""
    return update_memory(memory_id, status="superseded")


def get_memories_for_context(
    memory_types: list[str] | None = None,
    budget: int = 500,
) -> tuple[str, int]:
    """Get formatted memories for context injection.

    Returns (formatted_text, char_count).

    Budget allocation per Master Plan section 9:
      identity: 5%, preference: 5%, rest from retrieval budget
    """
    if memory_types is None:
        memory_types = ["identity", "preference"]

    memories = []
    for mtype in memory_types:
        memories.extend(get_memories(memory_type=mtype, min_confidence=0.5, limit=10))

    if not memories:
        return "", 0

    lines = ["--- AtoCore Memory ---"]
    used = len(lines[0]) + 1
    included = []

    for mem in memories:
        entry = f"[{mem.memory_type}] {mem.content}"
        entry_len = len(entry) + 1
        if used + entry_len > budget:
            break
        lines.append(entry)
        used += entry_len
        included.append(mem)

    if len(included) == 0:
        return "", 0

    lines.append("--- End Memory ---")
    text = "\n".join(lines)

    log.info("memories_for_context", count=len(included), chars=len(text))
    return text, len(text)


def _row_to_memory(row) -> Memory:
    """Convert a DB row to Memory dataclass."""
    return Memory(
        id=row["id"],
        memory_type=row["memory_type"],
        content=row["content"],
        project="",
        source_chunk_id=row["source_chunk_id"] or "",
        confidence=row["confidence"],
        status=row["status"],
        created_at=row["created_at"],
        updated_at=row["updated_at"],
    )