"""Threat actor data service.

Extracts query and business logic from the threat_actors router so
that the router remains a thin HTTP adapter.

This module is framework-agnostic: no FastAPI imports.
"""

# Enable future language features for compatibility
from __future__ import annotations

# Import Any from typing
from typing import Any

# Import case, func, or_ from sqlalchemy
from sqlalchemy import case, func, or_

# Import Session from sqlalchemy.orm
from sqlalchemy.orm import Session

# Import EntityNotFoundError from app.domain.errors
from app.domain.errors import EntityNotFoundError

# Import TechniqueStatus from app.models.enums
from app.models.enums import TechniqueStatus

# Import Technique from app.models.technique
from app.models.technique import Technique

# Import Test from app.models.test
from app.models.test import Test

# Import TestTemplate from app.models.test_template
from app.models.test_template import TestTemplate

# Import ThreatActor, ThreatActorTechnique from app.models.threat_actor
from app.models.threat_actor import ThreatActor, ThreatActorTechnique

# Import escape_like from app.utils
from app.utils import escape_like

# ── Public service functions ──────────────────────────────────────────


def list_actors(
    # Entry: db
    db: Session,
    *,
    # Entry: search
    search: str | None = None,
    # Entry: country
    country: str | None = None,
    # Entry: motivation
    motivation: str | None = None,
    # Entry: sophistication
    sophistication: str | None = None,
    # Entry: target_sectors
    target_sectors: str | None = None,
    # Entry: offset
    offset: int = 0,
    # Entry: limit
    limit: int = 50,
) -> dict[str, Any]:
    """List threat actors with optional filters, pagination, and coverage stats.

    Uses grouped subqueries to avoid N+1: technique counts and coverage
    counts are fetched in one query per page.
    """
    # Assign query = db.query(ThreatActor)
    query = db.query(ThreatActor)

    # Check: search
    if search:
        # Assign pattern = f"%{escape_like(search)}%"
        pattern = f"%{escape_like(search)}%"
        # Assign query = query.filter(
        query = query.filter(
            or_(
                ThreatActor.name.ilike(pattern),
                ThreatActor.description.ilike(pattern),
                func.cast(ThreatActor.aliases, func.text()).ilike(pattern),
            )
        )

    # Check: country
    if country:
        # Assign query = query.filter(ThreatActor.country == country)
        query = query.filter(ThreatActor.country == country)

    # Check: motivation
    if motivation:
        # Assign query = query.filter(ThreatActor.motivation == motivation)
        query = query.filter(ThreatActor.motivation == motivation)

    # Check: sophistication
    if sophistication:
        # Assign query = query.filter(ThreatActor.sophistication == sophistication)
        query = query.filter(ThreatActor.sophistication == sophistication)

    # Check: target_sectors
    if target_sectors:
        # Assign query = query.filter(
        query = query.filter(
            func.cast(ThreatActor.target_sectors, func.text()).ilike(
                f"%{escape_like(target_sectors)}%"
            )
        )

    # Assign total = query.count()
    total = query.count()
    # Assign actors = (
    actors = (
        query.order_by(ThreatActor.name).offset(offset).limit(limit).all()
    )

    # Check: not actors
    if not actors:
        # Return {
        return {
            # Literal argument value
            "total": total,
            # Literal argument value
            "offset": offset,
            # Literal argument value
            "limit": limit,
            # Literal argument value
            "items": [],
        }

    # Assign actor_ids = [a.id for a in actors]
    actor_ids = [a.id for a in actors]

    # Single grouped query: tech_count and covered_count per actor
    counts_rows = (
        db.query(
            ThreatActorTechnique.threat_actor_id,
            func.count(ThreatActorTechnique.id).label("tech_count"),
            func.sum(
                case(
                    (
                        Technique.status_global.in_([
                            TechniqueStatus.validated,
                            TechniqueStatus.partial,
                        ]),
                        # Literal argument value
                        1,
                    ),
                    # Keyword argument: else_
                    else_=0,
                )
            ).label("covered_count"),
        )
        # Chain .join() call
        .join(Technique, ThreatActorTechnique.technique_id == Technique.id)
        # Chain .filter() call
        .filter(ThreatActorTechnique.threat_actor_id.in_(actor_ids))
        # Chain .group_by() call
        .group_by(ThreatActorTechnique.threat_actor_id)
    ).all()

    # Assign counts_map = {
    counts_map = {
        str(row.threat_actor_id): {
            # Literal argument value
            "tech_count": row.tech_count,
            # Literal argument value
            "covered_count": row.covered_count or 0,
        }
        for row in counts_rows
    }

    # Assign results = []
    results = []
    # Iterate over actors
    for actor in actors:
        # Assign cnt = counts_map.get(str(actor.id), {"tech_count": 0, "covered_count": 0})
        cnt = counts_map.get(str(actor.id), {"tech_count": 0, "covered_count": 0})
        # Assign tech_count = cnt["tech_count"]
        tech_count = cnt["tech_count"]
        # Assign covered = cnt["covered_count"]
        covered = cnt["covered_count"]
        # Assign coverage_pct = round((covered / tech_count * 100), 1) if tech_count > 0 else 0.0
        coverage_pct = round((covered / tech_count * 100), 1) if tech_count > 0 else 0.0

        # Call results.append()
        results.append({
            # Literal argument value
            "id": str(actor.id),
            # Literal argument value
            "mitre_id": actor.mitre_id,
            # Literal argument value
            "name": actor.name,
            # Literal argument value
            "aliases": actor.aliases or [],
            # Literal argument value
            "country": actor.country,
            # Literal argument value
            "target_sectors": actor.target_sectors or [],
            # Literal argument value
            "target_regions": actor.target_regions or [],
            # Literal argument value
            "motivation": actor.motivation,
            # Literal argument value
            "sophistication": actor.sophistication,
            # Literal argument value
            "mitre_url": actor.mitre_url,
            # Literal argument value
            "technique_count": tech_count,
            # Literal argument value
            "coverage_pct": coverage_pct,
            # Literal argument value
            "is_active": actor.is_active,
        })

    # Return {
    return {
        # Literal argument value
        "total": total,
        # Literal argument value
        "offset": offset,
        # Literal argument value
        "limit": limit,
        # Literal argument value
        "items": results,
    }


# Define function get_actor_detail
def get_actor_detail(db: Session, actor_id: str) -> dict[str, Any]:
    """Get detailed threat actor with techniques.

    Raises EntityNotFoundError if the actor does not exist.
    """
    # Assign actor = db.query(ThreatActor).filter(ThreatActor.id == actor_id).first()
    actor = db.query(ThreatActor).filter(ThreatActor.id == actor_id).first()
    # Check: not actor
    if not actor:
        # Raise EntityNotFoundError
        raise EntityNotFoundError("Threat actor", actor_id)

    # Assign actor_techniques = (
    actor_techniques = (
        db.query(ThreatActorTechnique, Technique)
        # Chain .join() call
        .join(Technique, ThreatActorTechnique.technique_id == Technique.id)
        # Chain .filter() call
        .filter(ThreatActorTechnique.threat_actor_id == actor.id)
        # Chain .order_by() call
        .order_by(Technique.mitre_id)
        # Chain .all() call
        .all()
    )

    # Assign techniques_list = [
    techniques_list = [
        {
            # Literal argument value
            "technique_id": str(tech.id),
            # Literal argument value
            "mitre_id": tech.mitre_id,
            # Literal argument value
            "name": tech.name,
            # Literal argument value
            "tactic": tech.tactic,
            # Literal argument value
            "status_global": tech.status_global.value if tech.status_global else None,
            # Literal argument value
            "usage_description": at.usage_description,
            # Literal argument value
            "first_seen_using": at.first_seen_using,
        }
        for at, tech in actor_techniques
    ]

    # Return {
    return {
        # Literal argument value
        "id": str(actor.id),
        # Literal argument value
        "mitre_id": actor.mitre_id,
        # Literal argument value
        "name": actor.name,
        # Literal argument value
        "aliases": actor.aliases or [],
        # Literal argument value
        "description": actor.description,
        # Literal argument value
        "country": actor.country,
        # Literal argument value
        "target_sectors": actor.target_sectors or [],
        # Literal argument value
        "target_regions": actor.target_regions or [],
        # Literal argument value
        "motivation": actor.motivation,
        # Literal argument value
        "sophistication": actor.sophistication,
        # Literal argument value
        "first_seen": actor.first_seen,
        # Literal argument value
        "last_seen": actor.last_seen,
        # Literal argument value
        "references": actor.references or [],
        # Literal argument value
        "mitre_url": actor.mitre_url,
        # Literal argument value
        "is_active": actor.is_active,
        # Literal argument value
        "techniques": techniques_list,
    }


# Define function get_actor_coverage
def get_actor_coverage(db: Session, actor_id: str) -> dict[str, Any]:
    """Calculate coverage percentage against a specific threat actor.

    Raises EntityNotFoundError if the actor does not exist.
    """
    # Assign actor = db.query(ThreatActor).filter(ThreatActor.id == actor_id).first()
    actor = db.query(ThreatActor).filter(ThreatActor.id == actor_id).first()
    # Check: not actor
    if not actor:
        # Raise EntityNotFoundError
        raise EntityNotFoundError("Threat actor", actor_id)

    # Assign actor_techniques = (
    actor_techniques = (
        db.query(Technique)
        # Chain .join() call
        .join(ThreatActorTechnique, ThreatActorTechnique.technique_id == Technique.id)
        # Chain .filter() call
        .filter(ThreatActorTechnique.threat_actor_id == actor.id)
        # Chain .all() call
        .all()
    )

    # Assign total = len(actor_techniques)
    total = len(actor_techniques)
    # Check: total == 0
    if total == 0:
        # Return {
        return {
            # Literal argument value
            "actor_id": str(actor.id),
            # Literal argument value
            "actor_name": actor.name,
            # Literal argument value
            "total_techniques": 0,
            # Literal argument value
            "coverage_pct": 0.0,
            # Literal argument value
            "breakdown": {},
        }

    # Assign breakdown = {}
    breakdown: dict[str, int] = {}
    # Iterate over actor_techniques
    for tech in actor_techniques:
        # Assign status = tech.status_global.value if tech.status_global else "not_evaluated"
        status = tech.status_global.value if tech.status_global else "not_evaluated"
        # Assign breakdown[status] = breakdown.get(status, 0) + 1
        breakdown[status] = breakdown.get(status, 0) + 1

    # Assign covered = breakdown.get("validated", 0) + breakdown.get("partial", 0)
    covered = breakdown.get("validated", 0) + breakdown.get("partial", 0)
    # Assign coverage_pct = round((covered / total * 100), 1)
    coverage_pct = round((covered / total * 100), 1)

    # Return {
    return {
        # Literal argument value
        "actor_id": str(actor.id),
        # Literal argument value
        "actor_name": actor.name,
        # Literal argument value
        "total_techniques": total,
        # Literal argument value
        "covered": covered,
        # Literal argument value
        "coverage_pct": coverage_pct,
        # Literal argument value
        "breakdown": breakdown,
    }


# Define function get_actor_gaps
def get_actor_gaps(db: Session, actor_id: str) -> dict[str, Any]:
    """Identify techniques of this actor that are not fully validated.

    Raises EntityNotFoundError if the actor does not exist.
    """
    # Assign actor = db.query(ThreatActor).filter(ThreatActor.id == actor_id).first()
    actor = db.query(ThreatActor).filter(ThreatActor.id == actor_id).first()
    # Check: not actor
    if not actor:
        # Raise EntityNotFoundError
        raise EntityNotFoundError("Threat actor", actor_id)

    # Assign gap_techniques = (
    gap_techniques = (
        db.query(Technique, ThreatActorTechnique)
        # Chain .join() call
        .join(ThreatActorTechnique, ThreatActorTechnique.technique_id == Technique.id)
        # Chain .filter() call
        .filter(ThreatActorTechnique.threat_actor_id == actor.id)
        # Chain .filter() call
        .filter(Technique.status_global != TechniqueStatus.validated)
        # Chain .order_by() call
        .order_by(Technique.mitre_id)
        # Chain .all() call
        .all()
    )

    # Check: not gap_techniques
    if not gap_techniques:
        # Return {
        return {
            # Literal argument value
            "actor_id": str(actor.id),
            # Literal argument value
            "actor_name": actor.name,
            # Literal argument value
            "total_gaps": 0,
            # Literal argument value
            "gaps": [],
        }

    # Assign technique_ids = [tech.id for tech, _ in gap_techniques]
    technique_ids = [tech.id for tech, _ in gap_techniques]
    # Assign mitre_ids = [tech.mitre_id for tech, _ in gap_techniques]
    mitre_ids = [tech.mitre_id for tech, _ in gap_techniques]

    # Batch template counts by mitre_technique_id
    template_counts = (
        db.query(TestTemplate.mitre_technique_id, func.count(TestTemplate.id).label("cnt"))
        # Chain .filter() call
        .filter(TestTemplate.mitre_technique_id.in_(mitre_ids))
        # Chain .filter() call
        .filter(TestTemplate.is_active == True)
        # Chain .group_by() call
        .group_by(TestTemplate.mitre_technique_id)
    ).all()
    # Assign template_map = {row.mitre_technique_id: row.cnt for row in template_counts}
    template_map = {row.mitre_technique_id: row.cnt for row in template_counts}

    # Batch test counts by technique_id
    test_counts = (
        db.query(Test.technique_id, func.count(Test.id).label("cnt"))
        # Chain .filter() call
        .filter(Test.technique_id.in_(technique_ids))
        # Chain .group_by() call
        .group_by(Test.technique_id)
    ).all()
    # Assign test_map = {str(row.technique_id): row.cnt for row in test_counts}
    test_map = {str(row.technique_id): row.cnt for row in test_counts}

    # Assign gaps = []
    gaps = []
    # Iterate over gap_techniques
    for tech, at in gap_techniques:
        # Assign template_count = template_map.get(tech.mitre_id, 0)
        template_count = template_map.get(tech.mitre_id, 0)
        # Assign test_count = test_map.get(str(tech.id), 0)
        test_count = test_map.get(str(tech.id), 0)
        # Call gaps.append()
        gaps.append({
            # Literal argument value
            "technique_id": str(tech.id),
            # Literal argument value
            "mitre_id": tech.mitre_id,
            # Literal argument value
            "name": tech.name,
            # Literal argument value
            "tactic": tech.tactic,
            # Literal argument value
            "status_global": tech.status_global.value if tech.status_global else None,
            # Literal argument value
            "usage_description": at.usage_description,
            # Literal argument value
            "available_templates": template_count,
            # Literal argument value
            "existing_tests": test_count,
            # Literal argument value
            "has_templates": template_count > 0,
        })

    # Return {
    return {
        # Literal argument value
        "actor_id": str(actor.id),
        # Literal argument value
        "actor_name": actor.name,
        # Literal argument value
        "total_gaps": len(gaps),
        # Literal argument value
        "gaps": gaps,
    }