"""Test-template CRUD endpoints.

Reads gated by `test_template.read`. Writes gated by `test_template.{create,
update,delete}`. Service layer handles all DB work; this module only validates
the wire payload and shapes the JSON response.
"""

from __future__ import annotations

import logging
import uuid
from typing import Any

from flask import Blueprint, jsonify, request
from pydantic import BaseModel, Field, StringConstraints, ValidationError
from typing import Annotated

from app.core.auth_decorators import require_auth, require_perm
from app.services import test_templates as svc

# Tag and IOC entries are stored as PG ARRAY(String(N)). Cap items at the wire
# layer so over-sized inputs return 400 with a useful message rather than the
# bare StringDataRightTruncation from the driver.
TagStr = Annotated[str, StringConstraints(min_length=1, max_length=64)]
IocStr = Annotated[str, StringConstraints(min_length=1, max_length=255)]

bp = Blueprint("test_templates", __name__, url_prefix="/test-templates")
log = logging.getLogger("metamorph.api.test_templates")


# === Payload schemas ==========================================================


class MitreTagIn(BaseModel):
    kind: str = Field(min_length=1)
    external_id: str = Field(min_length=1, max_length=16)

    model_config = {"extra": "forbid"}


class CreateTestTemplatePayload(BaseModel):
    name: str = Field(min_length=1, max_length=255)
    description: str | None = Field(default=None, max_length=4000)
    objective: str | None = Field(default=None, max_length=4000)
    procedure_md: str | None = Field(default=None, max_length=32_000)
    prerequisites_md: str | None = Field(default=None, max_length=32_000)
    expected_result_red_md: str | None = Field(default=None, max_length=32_000)
    expected_detection_blue_md: str | None = Field(default=None, max_length=32_000)
    opsec_level: str = Field(default="medium")
    tags: list[TagStr] = Field(default_factory=list, max_length=64)
    expected_iocs: list[IocStr] = Field(default_factory=list, max_length=128)
    mitre_tags: list[MitreTagIn] = Field(default_factory=list, max_length=64)

    model_config = {"extra": "forbid"}


class UpdateTestTemplatePayload(BaseModel):
    name: str | None = Field(default=None, min_length=1, max_length=255)
    description: str | None = Field(default=None, max_length=4000)
    objective: str | None = Field(default=None, max_length=4000)
    procedure_md: str | None = Field(default=None, max_length=32_000)
    prerequisites_md: str | None = Field(default=None, max_length=32_000)
    expected_result_red_md: str | None = Field(default=None, max_length=32_000)
    expected_detection_blue_md: str | None = Field(default=None, max_length=32_000)
    opsec_level: str | None = None
    tags: list[TagStr] | None = Field(default=None, max_length=64)
    expected_iocs: list[IocStr] | None = Field(default=None, max_length=128)
    mitre_tags: list[MitreTagIn] | None = Field(default=None, max_length=64)

    model_config = {"extra": "forbid"}


# === Serializers ==============================================================


def _serialize(t: svc.TestTemplateView) -> dict[str, Any]:
    return {
        "id": str(t.id),
        "name": t.name,
        "description": t.description,
        "objective": t.objective,
        "procedure_md": t.procedure_md,
        "prerequisites_md": t.prerequisites_md,
        "expected_result_red_md": t.expected_result_red_md,
        "expected_detection_blue_md": t.expected_detection_blue_md,
        "opsec_level": t.opsec_level,
        "tags": list(t.tags),
        "expected_iocs": list(t.expected_iocs),
        "mitre_tags": [
            {"kind": tag.kind, "external_id": tag.external_id, "name": tag.name, "url": tag.url}
            for tag in t.mitre_tags
        ],
        "deleted_at": t.deleted_at.isoformat() if t.deleted_at else None,
        "created_at": t.created_at.isoformat(),
        "updated_at": t.updated_at.isoformat(),
    }


def _parse_uuid_or_400(raw: str):
    try:
        return uuid.UUID(raw)
    except ValueError:
        return None


def _pagination_args() -> tuple[int, int] | tuple[None, tuple[int, str]]:
    try:
        limit = int(request.args.get("limit", "100"))
        offset = int(request.args.get("offset", "0"))
    except ValueError:
        return None, (400, "invalid_pagination")
    return max(1, min(limit, 500)), max(0, offset)


# === Endpoints ================================================================


@bp.get("")
@require_auth
@require_perm("test_template.read")
def list_test_templates():
    paging = _pagination_args()
    if paging[0] is None:
        return jsonify({"error": paging[1][1]}), paging[1][0]
    limit, offset = paging
    q = request.args.get("q") or None
    tactic = request.args.get("tactic") or None
    technique = request.args.get("technique") or None
    subtechnique = request.args.get("subtechnique") or None
    opsec_level = request.args.get("opsec") or None
    tag = request.args.get("tag") or None
    include_deleted = request.args.get("include_deleted", "false").lower() == "true"
    try:
        items, total = svc.list_test_templates(
            q=q,
            tactic=tactic,
            technique=technique,
            subtechnique=subtechnique,
            opsec_level=opsec_level,
            tag=tag,
            include_deleted=include_deleted,
            limit=limit,
            offset=offset,
        )
    except ValueError as e:
        return jsonify({"error": "invalid_request", "message": str(e)}), 400
    return jsonify(
        {
            "items": [_serialize(it) for it in items],
            "total": total,
            "limit": limit,
            "offset": offset,
        }
    )


@bp.get("/<template_id>")
@require_auth
@require_perm("test_template.read")
def get_test_template(template_id: str):
    tid = _parse_uuid_or_400(template_id)
    if tid is None:
        return jsonify({"error": "invalid_id"}), 400
    include_deleted = request.args.get("include_deleted", "false").lower() == "true"
    try:
        view = svc.get_test_template(tid, include_deleted=include_deleted)
    except svc.TestTemplateNotFound:
        return jsonify({"error": "not_found"}), 404
    return jsonify(_serialize(view))


@bp.post("")
@require_auth
@require_perm("test_template.create")
def create_test_template():
    try:
        payload = CreateTestTemplatePayload.model_validate(request.get_json(silent=True) or {})
    except ValidationError as e:
        return jsonify({"error": "invalid_request", "details": e.errors(include_context=False, include_url=False)}), 400
    try:
        view = svc.create_test_template(
            name=payload.name,
            description=payload.description,
            objective=payload.objective,
            procedure_md=payload.procedure_md,
            prerequisites_md=payload.prerequisites_md,
            expected_result_red_md=payload.expected_result_red_md,
            expected_detection_blue_md=payload.expected_detection_blue_md,
            opsec_level=payload.opsec_level,
            tags=payload.tags,
            expected_iocs=payload.expected_iocs,
            mitre_tags=[svc.MitreTagRef(kind=t.kind, external_id=t.external_id) for t in payload.mitre_tags],
        )
    except svc.UnknownMitreTag as e:
        return jsonify({"error": "unknown_mitre_tag", "message": str(e)}), 400
    except ValueError as e:
        return jsonify({"error": "invalid_request", "message": str(e)}), 400
    log.info(
        "metamorph.test_template.created",
        extra={"id": str(view.id), "template_name": view.name},
    )
    return jsonify(_serialize(view)), 201


@bp.put("/<template_id>")
@require_auth
@require_perm("test_template.update")
def update_test_template(template_id: str):
    tid = _parse_uuid_or_400(template_id)
    if tid is None:
        return jsonify({"error": "invalid_id"}), 400
    raw = request.get_json(silent=True) or {}
    try:
        payload = UpdateTestTemplatePayload.model_validate(raw)
    except ValidationError as e:
        return jsonify({"error": "invalid_request", "details": e.errors(include_context=False, include_url=False)}), 400

    # Only forward keys actually present in the body — model_validate leaves
    # missing fields as None and we can't distinguish "explicitly null" from
    # "omitted". The set of keys in `raw` is the wire-level intent.
    kwargs: dict[str, Any] = {}
    for field_name in (
        "name", "description", "objective", "procedure_md", "prerequisites_md",
        "expected_result_red_md", "expected_detection_blue_md",
        "opsec_level", "tags", "expected_iocs",
    ):
        if field_name in raw:
            kwargs[field_name] = getattr(payload, field_name)
    if "mitre_tags" in raw:
        kwargs["mitre_tags"] = (
            [svc.MitreTagRef(kind=t.kind, external_id=t.external_id) for t in (payload.mitre_tags or [])]
        )
    try:
        view = svc.update_test_template(tid, **kwargs)
    except svc.TestTemplateNotFound:
        return jsonify({"error": "not_found"}), 404
    except svc.UnknownMitreTag as e:
        return jsonify({"error": "unknown_mitre_tag", "message": str(e)}), 400
    except ValueError as e:
        return jsonify({"error": "invalid_request", "message": str(e)}), 400
    log.info("metamorph.test_template.updated", extra={"id": str(tid), "fields": sorted(kwargs.keys())})
    return jsonify(_serialize(view))


@bp.delete("/<template_id>")
@require_auth
@require_perm("test_template.delete")
def soft_delete_test_template(template_id: str):
    tid = _parse_uuid_or_400(template_id)
    if tid is None:
        return jsonify({"error": "invalid_id"}), 400
    try:
        svc.soft_delete_test_template(tid)
    except svc.TestTemplateNotFound:
        return jsonify({"error": "not_found"}), 404
    log.info("metamorph.test_template.soft_deleted", extra={"id": str(tid)})
    return jsonify({"ok": True})