"""Procedure-improvement suggestion workflow.

When an operator submits a round with a filled-in procedure field, the
command(s) in it are extracted heuristically (see
``procedure_extraction_service``) and proposed as an update to the
originating template's suggested-procedure field. A suggestion is only
ever created when there's a real, novel improvement to propose — nothing
is written to the template until a lead reviews and approves it, and
approving one only ever appends new commands, never overwrites or drops
whatever earlier approved rounds already contributed.
"""

from __future__ import annotations

import uuid
from datetime import datetime

from sqlalchemy.orm import Session

from app.domain.errors import EntityNotFoundError, InvalidOperationError
from app.models.procedure_suggestion import ProcedureSuggestion
from app.models.test import Test
from app.models.test_template import TestTemplate
from app.models.user import User
from app.services.notification_service import notify_role
from app.services.procedure_extraction_service import extract_commands

# Which Test field holds the operator's free-text procedure, and which
# TestTemplate field it's proposed as an improvement to, per team.
_SOURCE_FIELD = {"red": "procedure_text", "blue": "detect_procedure"}
_TEMPLATE_FIELD = {"red": "attack_procedure", "blue": "expected_detection"}
_LEAD_ROLE = {"red": "red_lead", "blue": "blue_lead"}


def _new_lines(current: str | None, suggested: str) -> list[str]:
    """Lines in *suggested* not already present verbatim in *current*.

    Line-level, not whole-text: a later round's extraction is usually a
    different subset/superset of commands than an earlier one, so an exact
    string comparison would treat almost every resubmission as "novel" and
    then, on approval, blow away whatever an earlier approved round already
    contributed.
    """
    existing = {line.strip() for line in (current or "").splitlines() if line.strip()}
    seen: set[str] = set()
    new: list[str] = []
    for line in suggested.splitlines():
        stripped = line.strip()
        if not stripped or stripped in existing or stripped in seen:
            continue
        new.append(stripped)
        seen.add(stripped)
    return new


def _merge_procedure_text(current: str | None, suggested: str) -> str:
    """Append genuinely new lines from *suggested* onto *current*.

    Approving a suggestion must only ever grow a template's procedure,
    never replace it — otherwise a narrower extraction from a later round
    would silently erase commands an earlier approved round already added.
    """
    current_stripped = (current or "").strip()
    new = _new_lines(current, suggested)
    if not new:
        return current_stripped
    if not current_stripped:
        return "\n".join(new)
    return current_stripped + "\n" + "\n".join(new)


def create_suggestion_from_submission(db: Session, test: Test, team: str) -> ProcedureSuggestion | None:
    """Propose a template procedure improvement from *test*'s just-submitted round.

    Returns the created (unflushed-to-caller-commit) suggestion, or ``None``
    when there's nothing worth proposing: the test wasn't created from a
    template, no command could be extracted, the extraction matches what
    the template already suggests, or an identical suggestion is already
    pending review. Does not commit; caller uses UnitOfWork.
    """
    if not test.source_template_id:
        return None

    procedure_text = getattr(test, _SOURCE_FIELD[team])
    extracted = extract_commands(procedure_text)
    if not extracted:
        return None

    template = db.query(TestTemplate).filter(TestTemplate.id == test.source_template_id).first()
    if template is None:
        return None

    current = getattr(template, _TEMPLATE_FIELD[team])
    if not _new_lines(current, extracted):
        return None

    duplicate = (
        db.query(ProcedureSuggestion)
        .filter(
            ProcedureSuggestion.template_id == template.id,
            ProcedureSuggestion.team == team,
            ProcedureSuggestion.suggested_text == extracted,
            ProcedureSuggestion.status == "pending",
        )
        .first()
    )
    if duplicate is not None:
        return None

    submitter_id = test.red_tech_assignee if team == "red" else test.blue_tech_assignee
    suggestion = ProcedureSuggestion(
        template_id=template.id,
        team=team,
        suggested_text=extracted,
        source_test_id=test.id,
        submitted_by=submitter_id,
    )
    db.add(suggestion)
    db.flush()

    notify_role(
        db,
        role=_LEAD_ROLE[team],
        type="procedure_suggestion",
        title="New procedure suggestion for review",
        message=f'A {team} procedure improvement was proposed for template "{template.name}".',
        entity_type="procedure_suggestion",
        entity_id=suggestion.id,
    )

    return suggestion


def list_pending_suggestions(db: Session, *, team: str | None = None) -> list[ProcedureSuggestion]:
    """List pending suggestions, optionally filtered to one team."""
    query = db.query(ProcedureSuggestion).filter(ProcedureSuggestion.status == "pending")
    if team is not None:
        query = query.filter(ProcedureSuggestion.team == team)
    return query.order_by(ProcedureSuggestion.created_at.asc()).all()


def _get_pending_suggestion_or_raise(db: Session, suggestion_id: uuid.UUID) -> ProcedureSuggestion:
    suggestion = db.query(ProcedureSuggestion).filter(ProcedureSuggestion.id == suggestion_id).first()
    if suggestion is None:
        raise EntityNotFoundError("ProcedureSuggestion", str(suggestion_id))
    if suggestion.status != "pending":
        raise InvalidOperationError("This suggestion has already been reviewed.")
    return suggestion


def approve_suggestion(db: Session, suggestion_id: uuid.UUID, user: User) -> ProcedureSuggestion:
    """Approve a suggestion: write it into the template and mark reviewed. Does not commit."""
    suggestion = _get_pending_suggestion_or_raise(db, suggestion_id)
    template = db.query(TestTemplate).filter(TestTemplate.id == suggestion.template_id).first()
    if template is None:
        raise EntityNotFoundError("TestTemplate", str(suggestion.template_id))

    current_text = getattr(template, _TEMPLATE_FIELD[suggestion.team])
    setattr(template, _TEMPLATE_FIELD[suggestion.team], _merge_procedure_text(current_text, suggestion.suggested_text))
    suggestion.status = "approved"
    suggestion.reviewed_by = user.id
    suggestion.reviewed_at = datetime.utcnow()
    db.flush()
    return suggestion


def reject_suggestion(db: Session, suggestion_id: uuid.UUID, user: User) -> ProcedureSuggestion:
    """Reject a suggestion without touching the template. Does not commit."""
    suggestion = _get_pending_suggestion_or_raise(db, suggestion_id)
    suggestion.status = "rejected"
    suggestion.reviewed_by = user.id
    suggestion.reviewed_at = datetime.utcnow()
    db.flush()
    return suggestion