"""Editing the shipped system prompts.

Every prompt has a code default; a row exists only where an admin changed one,
and resetting deletes that row rather than storing a copy of the default. The
UI labels the keys from its own messages, so nothing user-facing is worded here.
"""

from typing import Annotated

from fastapi import Depends
from pydantic import BaseModel
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

from app.api.admin.routing import admin_router
from app.db import get_db
from app.errors import ApiError
from app.models import PromptSetting
from app.prompts.defaults import DEFAULTS, PROMPT_KEYS
from app.prompts.overrides import get_prompt, is_overridden
from app.prompts.overrides import load_config as load_prompt_config

router = admin_router()


class PromptSettingOut(BaseModel):
    key: str
    # The effective text: an admin override if present, else the code default.
    content: str
    # True when no override exists, i.e. the shipped default is in force.
    is_default: bool


class PromptSettingUpdate(BaseModel):
    # New override text, or `reset` to drop the override back to the default.
    content: str | None = None
    reset: bool | None = None


@router.get("/prompts")
async def prompt_settings(
    db: Annotated[AsyncSession, Depends(get_db)],
) -> list[PromptSettingOut]:
    """Every editable system prompt with its effective text and whether it is
    still the shipped default."""
    rows = {row.key: row for row in (await db.execute(select(PromptSetting))).scalars()}
    return [
        PromptSettingOut(
            key=key,
            content=rows[key].content if key in rows else DEFAULTS[key],
            is_default=key not in rows,
        )
        for key in PROMPT_KEYS
    ]


@router.put("/prompts/{key}")
async def update_prompt_setting(
    key: str,
    body: PromptSettingUpdate,
    db: Annotated[AsyncSession, Depends(get_db)],
) -> PromptSettingOut:
    """Override a system prompt (applied without a restart) or reset it to the
    shipped default. Resetting deletes the override row."""
    if key not in DEFAULTS:
        raise ApiError(404, "Unknown prompt.", "not_found")
    row = (
        await db.execute(select(PromptSetting).where(PromptSetting.key == key))
    ).scalar_one_or_none()

    if body.reset:
        if row is not None:
            await db.delete(row)
    elif body.content is not None:
        content = body.content.strip()
        if not content:
            raise ApiError(422, "A prompt cannot be empty.", "empty_prompt")
        if row is None:
            db.add(PromptSetting(key=key, content=content))
        else:
            row.content = content

    await db.commit()
    await load_prompt_config(db)
    return PromptSettingOut(
        key=key, content=get_prompt(key), is_default=not is_overridden(key)
    )