"""Single prompt execution entry. Templates live in the DB; LLM egress only via Privacy Gateway."""
from __future__ import annotations

from typing import Any

import placeholder_mvp  # noqa: F401
import placeholder_system  # noqa: F401  registers system keys
import privacy_placeholders
from db import get_db, row_to_dict
from entitlements import EntitlementError, check_feature_access, increment_feature_usage
from placeholders import PlaceholderError, resolve_template
from privacy_gateway import GatewayRequest, PrivacyGatewayError, complete, last_trace, public_trace


class EngineError(Exception):
    def __init__(self, code: str, message: str, status_code: int = 400):
        super().__init__(message)
        self.code = code
        self.message = message
        self.status_code = status_code


def load_active_prompt(slug: str) -> dict:
    with get_db() as conn:
        row = row_to_dict(
            conn.execute(
                "SELECT * FROM ai_prompts WHERE slug = ? AND active = 1",
                (slug,),
            ).fetchone()
        )
    if not row:
        raise EngineError("prompt_missing", f"Prompt fehlt oder ist inaktiv: {slug}", 404)
    return row


def preview_prompt(prompt: dict, context: dict[str, Any] | None = None) -> dict:
    template = prompt.get("template") or ""
    if prompt.get("prompt_type") != "base":
        raise EngineError("prompt_type_not_ready", "Pipeline- und Workflow-Typen sind vorbereitet, aber noch ohne Executor-Stufen.")
    try:
        rendered = resolve_template(template, context or {})
        privacy_tokens = privacy_placeholders.validate_tokens(template)
    except PlaceholderError as exc:
        raise EngineError(exc.code, exc.message) from exc
    return {
        "prompt_id": prompt["id"],
        "slug": prompt["slug"],
        "rendered": rendered,
        "privacy_tokens": privacy_tokens,
        "llm": False,
    }


def user_source_text(dialogue_context: str) -> str:
    parts = []
    for line in (dialogue_context or "").splitlines():
        if line.startswith("user:"):
            parts.append(line[5:].lstrip())
    return "\n".join(parts)


def execute_prompt(prompt: dict, profile_id: str, purpose: str, data_class: str, context: dict[str, Any] | None = None) -> dict:
    preview = preview_prompt(prompt, context)
    feature_id = prompt.get("required_feature") or "ai_calls"
    try:
        check_feature_access(profile_id, feature_id)
    except EntitlementError as exc:
        raise EngineError(exc.code, exc.message, exc.status_code) from exc
    try:
        ctx = context or {}
        source_text = user_source_text(ctx.get("dialogue_context") or "")
        extras = []
        if purpose == "journal_generate":
            extras = [part for part in (ctx.get("existing_text"), ctx.get("writing_profile")) if part]
        elif purpose == "profile_review":
            source_text = ctx.get("source_text") or ""
            extras = [part for part in (ctx.get("review_package"),) if part]
        if extras:
            source_text = "\n".join(part for part in (source_text, *extras) if part)
        elif not source_text:
            source_text = "\n".join(
                part for part in (ctx.get("existing_text"), ctx.get("writing_profile")) if part
            )
        result = complete(
            GatewayRequest(
                prompt_id=prompt["id"],
                purpose=purpose,
                data_class=data_class,
                profile_id=profile_id,
                payload={
                    "rendered": preview["rendered"],
                    "source_text": source_text,
                    "privacy_tokens": preview["privacy_tokens"],
                    "prompt_slug": prompt.get("slug"),
                },
            )
        )
    except PrivacyGatewayError as exc:
        raise EngineError(exc.code, exc.message, exc.status_code) from exc
    increment_feature_usage(profile_id, feature_id)
    return {
        **preview,
        "llm": True,
        "content": result.content,
        "provider": result.provider,
        "trace": public_trace(last_trace()),
    }