"""
Admin-only settings API for per-service runtime configuration.

All endpoints require the caller to be an admin (Depends(get_current_admin)).
Config files live on the shared app_config volume (/config/).
"""
import asyncio

import httpx
from fastapi import APIRouter, Depends, HTTPException
from pydantic import BaseModel

from app.core.app_config import (
    SYSTEM_PROMPT_SERVICES,
    _merge_api_key,
    load_ai_service_config,
    load_ai_service_config_masked,
    load_all_system_prompts,
    load_doc_service_config,
    load_doc_service_config_masked,
    save_ai_service_config,
    save_doc_service_config,
    save_service_system_prompts,
)
from app.core.config import settings
from app.deps import get_current_admin
from app.models.user import User

router = APIRouter()


# ── Pydantic request bodies ────────────────────────────────────────────────────


class AIProviderUpdate(BaseModel):
    provider: str
    anthropic_api_key: str = ""
    anthropic_model: str = ""
    ollama_base_url: str = ""
    ollama_model: str = ""
    ollama_api_key: str = ""
    lmstudio_base_url: str = ""
    lmstudio_model: str = ""
    lmstudio_api_key: str = ""


class LimitsUpdate(BaseModel):
    max_pdf_mb: int


class SystemPromptUpdate(BaseModel):
    system: str
    user_template: str


# ── AI settings ────────────────────────────────────────────────────────────────


@router.get("/ai")
async def get_ai_settings(
    _: User = Depends(get_current_admin),
) -> dict:
    return load_ai_service_config_masked()


@router.patch("/ai")
async def update_ai_settings(
    body: AIProviderUpdate,
    _: User = Depends(get_current_admin),
) -> dict:
    valid_providers = ("anthropic", "ollama", "lmstudio")
    if body.provider not in valid_providers:
        raise HTTPException(status_code=422, detail=f"provider must be one of {valid_providers}")

    config = load_ai_service_config()
    config.provider = body.provider

    # Anthropic
    if body.anthropic_api_key:
        config.anthropic.api_key = _merge_api_key(
            body.anthropic_api_key, config.anthropic.api_key
        )
    if body.anthropic_model:
        config.anthropic.model = body.anthropic_model

    # Ollama
    if body.ollama_base_url:
        config.ollama.base_url = body.ollama_base_url
    if body.ollama_model:
        config.ollama.model = body.ollama_model
    if body.ollama_api_key:
        config.ollama.api_key = _merge_api_key(body.ollama_api_key, config.ollama.api_key)

    # LM Studio
    if body.lmstudio_base_url:
        config.lmstudio.base_url = body.lmstudio_base_url
    if body.lmstudio_model:
        config.lmstudio.model = body.lmstudio_model
    if body.lmstudio_api_key:
        config.lmstudio.api_key = _merge_api_key(
            body.lmstudio_api_key, config.lmstudio.api_key
        )

    await asyncio.to_thread(save_ai_service_config, config)
    return load_ai_service_config_masked()


@router.post("/ai/test")
async def test_ai_connection(
    _: User = Depends(get_current_admin),
) -> dict:
    """Proxy a minimal chat request to ai-service to verify the connection."""
    try:
        async with httpx.AsyncClient(timeout=30.0) as client:
            resp = await client.post(
                f"{settings.AI_SERVICE_URL}/chat",
                json={
                    "messages": [{"role": "user", "content": "Reply with: ok"}],
                    "max_tokens": 16,
                    "temperature": 0,
                },
            )
        if resp.status_code == 200:
            data = resp.json()
            return {"ok": True, "provider": data.get("provider"), "response": data.get("content")}
        return {"ok": False, "error": f"ai-service returned {resp.status_code}: {resp.text[:200]}"}
    except Exception as exc:
        return {"ok": False, "error": str(exc)}


# ── Document limits ────────────────────────────────────────────────────────────


@router.get("/documents/limits")
async def get_documents_limits(
    _: User = Depends(get_current_admin),
) -> dict:
    return load_doc_service_config_masked()


@router.patch("/documents/limits")
async def update_documents_limits(
    body: LimitsUpdate,
    _: User = Depends(get_current_admin),
) -> dict:
    if body.max_pdf_mb < 1 or body.max_pdf_mb > 200:
        raise HTTPException(status_code=422, detail="max_pdf_mb must be between 1 and 200")

    config = load_doc_service_config()
    config.documents.max_pdf_bytes = body.max_pdf_mb * 1024 * 1024
    await asyncio.to_thread(save_doc_service_config, config)
    return load_doc_service_config_masked()


# ── System prompts ─────────────────────────────────────────────────────────────


@router.get("/system-prompts")
async def get_system_prompts(
    _: User = Depends(get_current_admin),
) -> dict:
    """Return all editable system prompts, keyed by service id."""
    return await asyncio.to_thread(load_all_system_prompts)


@router.patch("/system-prompts/{service_id}")
async def update_system_prompt(
    service_id: str,
    body: SystemPromptUpdate,
    _: User = Depends(get_current_admin),
) -> dict:
    """Update the system prompts for a single service."""
    if service_id not in SYSTEM_PROMPT_SERVICES:
        raise HTTPException(status_code=404, detail=f"No system prompts registered for {service_id!r}")
    await asyncio.to_thread(
        save_service_system_prompts, service_id, body.system, body.user_template
    )
    return await asyncio.to_thread(load_all_system_prompts)