"""Coverage report data service.

Extracts query and aggregation logic from the reports router so
that the router remains a thin HTTP adapter.  Fixes the N+1
technique/test-count pattern by using a single grouped query.

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

from __future__ import annotations

from datetime import datetime

from sqlalchemy import func
from sqlalchemy.orm import Session

from app.models.technique import Technique
from app.models.test import Test
from app.utils import escape_like


def _technique_test_counts(
    db: Session,
    technique_ids: list,
) -> dict:
    """Return ``{technique_id: {state_str: count}}`` in a single query."""
    if not technique_ids:
        return {}
    rows = (
        db.query(Test.technique_id, Test.state, func.count(Test.id))
        .filter(Test.technique_id.in_(technique_ids))
        .group_by(Test.technique_id, Test.state)
        .all()
    )
    result: dict = {}
    for tid, state, count in rows:
        result.setdefault(tid, {})[str(state)] = count
    return result


def build_coverage_summary(
    db: Session,
    *,
    tactic: str | None = None,
    platform: str | None = None,
) -> dict:
    """Build the full coverage summary report as a dict."""
    query = db.query(Technique)
    if tactic:
        query = query.filter(Technique.tactic.ilike(f"%{escape_like(tactic)}%"))

    techniques = query.order_by(Technique.mitre_id).all()
    counts_map = _technique_test_counts(db, [t.id for t in techniques])

    rows = []
    for t in techniques:
        if platform and platform.lower() not in [p.lower() for p in (t.platforms or [])]:
            continue

        counts = counts_map.get(t.id, {})
        rows.append({
            "mitre_id": t.mitre_id,
            "name": t.name,
            "tactic": t.tactic,
            "platforms": t.platforms,
            "status_global": t.status_global,
            "total_tests": sum(counts.values()),
            "tests_by_state": counts,
        })

    total = len(rows)
    validated = sum(1 for r in rows if r["status_global"] == "validated")
    partial = sum(1 for r in rows if r["status_global"] == "partial")
    not_covered = sum(1 for r in rows if r["status_global"] == "not_covered")
    in_progress = sum(1 for r in rows if r["status_global"] == "in_progress")
    not_evaluated = sum(1 for r in rows if r["status_global"] == "not_evaluated")

    return {
        "generated_at": datetime.utcnow().isoformat(),
        "summary": {
            "total_techniques": total,
            "validated": validated,
            "partial": partial,
            "not_covered": not_covered,
            "in_progress": in_progress,
            "not_evaluated": not_evaluated,
            "coverage_percentage": round((validated / total * 100) if total > 0 else 0, 1),
        },
        "techniques": rows,
    }


def build_coverage_csv_rows(
    db: Session,
    *,
    tactic: str | None = None,
    platform: str | None = None,
) -> list[list]:
    """Build rows for a CSV coverage export (header + data)."""
    query = db.query(Technique)
    if tactic:
        query = query.filter(Technique.tactic.ilike(f"%{escape_like(tactic)}%"))

    techniques = query.order_by(Technique.mitre_id).all()
    counts_map = _technique_test_counts(db, [t.id for t in techniques])

    header = [
        "MITRE ID", "Name", "Tactic", "Platforms", "Status",
        "Total Tests", "Validated", "In Progress", "Not Covered",
    ]
    rows = [header]

    in_progress_states = {"draft", "red_executing", "blue_evaluating", "in_review"}

    for t in techniques:
        if platform and platform.lower() not in [p.lower() for p in (t.platforms or [])]:
            continue

        counts = counts_map.get(t.id, {})
        rows.append([
            t.mitre_id,
            t.name,
            t.tactic,
            ", ".join(t.platforms or []),
            t.status_global,
            sum(counts.values()),
            counts.get("validated", 0),
            sum(counts.get(s, 0) for s in in_progress_states),
            counts.get("rejected", 0),
        ])

    return rows


def build_test_results_report(
    db: Session,
    *,
    state: str | None = None,
    date_from: str | None = None,
    date_to: str | None = None,
) -> dict:
    """Build a test results report with optional filters."""
    query = db.query(Test)

    if state:
        query = query.filter(Test.state == state)
    if date_from:
        try:
            query = query.filter(Test.created_at >= datetime.fromisoformat(date_from))
        except ValueError:
            pass
    if date_to:
        try:
            query = query.filter(Test.created_at <= datetime.fromisoformat(date_to))
        except ValueError:
            pass

    tests = query.order_by(Test.created_at.desc()).all()

    by_state: dict[str, int] = {}
    by_result: dict[str, int] = {}
    for t in tests:
        s = t.state.value if hasattr(t.state, "value") else str(t.state)
        by_state[s] = by_state.get(s, 0) + 1
        if t.detection_result:
            r = t.detection_result.value if hasattr(t.detection_result, "value") else str(t.detection_result)
            by_result[r] = by_result.get(r, 0) + 1

    return {
        "generated_at": datetime.utcnow().isoformat(),
        "filters": {"state": state, "date_from": date_from, "date_to": date_to},
        "summary": {
            "total_tests": len(tests),
            "by_state": by_state,
            "by_detection_result": by_result,
        },
        "tests": [
            {
                "id": str(t.id),
                "name": t.name,
                "technique_id": str(t.technique_id),
                "state": t.state.value if hasattr(t.state, "value") else str(t.state),
                "platform": t.platform,
                "attack_success": t.attack_success,
                "detection_result": (
                    t.detection_result.value if t.detection_result and hasattr(t.detection_result, "value")
                    else str(t.detection_result) if t.detection_result else None
                ),
                "red_validation_status": t.red_validation_status,
                "blue_validation_status": t.blue_validation_status,
                "created_at": t.created_at.isoformat() if t.created_at else None,
            }
            for t in tests
        ],
    }


def build_remediation_status_report(
    db: Session,
    *,
    status: str | None = None,
) -> dict:
    """Build a remediation status report."""
    query = db.query(Test).filter(Test.remediation_steps.isnot(None))

    if status:
        query = query.filter(Test.remediation_status == status)

    tests = query.order_by(Test.created_at.desc()).all()

    by_status: dict[str, int] = {}
    for t in tests:
        s = t.remediation_status or "unset"
        by_status[s] = by_status.get(s, 0) + 1

    return {
        "generated_at": datetime.utcnow().isoformat(),
        "summary": {
            "total_with_remediation": len(tests),
            "by_status": by_status,
        },
        "tests": [
            {
                "id": str(t.id),
                "name": t.name,
                "technique_id": str(t.technique_id),
                "state": t.state.value if hasattr(t.state, "value") else str(t.state),
                "remediation_status": t.remediation_status,
                "remediation_steps": t.remediation_steps,
                "remediation_assignee": str(t.remediation_assignee) if t.remediation_assignee else None,
            }
            for t in tests
        ],
    }