"""Template library endpoints.

Templates are stack-shaped folders on disk. Listing reads them; "instantiate"
(pull) copies the whole folder into a new stack, which is then editable.
"""
from __future__ import annotations

import os

from fastapi import APIRouter, Depends, HTTPException, Request
from sqlmodel import Session

from auth import get_current_user, require_admin
from database import get_session
from models.agent import Agent
from models.stack import Stack
from models.template import (
    TemplateFromStackRequest,
    TemplateInstantiateRequest,
    TemplateSaveRequest,
)
from models.user import User
from services import agent_service, audit_service, compose_service, template_service
from services.agent_service import AgentError

router = APIRouter(prefix="/api/templates", tags=["templates"])


def _ip(request: Request) -> str:
    return request.client.host if request.client else "unknown"


@router.get("")
def list_templates(
    _user: User = Depends(get_current_user),
) -> list[dict]:
    return template_service.list_templates()


@router.get("/{template_id}")
def get_template(
    template_id: str,
    _user: User = Depends(get_current_user),
) -> dict:
    tpl = template_service.get_template(template_id)
    if not tpl:
        raise HTTPException(status_code=404, detail="Template not found")
    return tpl


@router.post("")
def save_template(
    body: TemplateSaveRequest,
    request: Request,
    session: Session = Depends(get_session),
    user: User = Depends(require_admin),
) -> dict:
    slug = template_service.save_custom(
        body.name, body.compose, body.env, body.description or "", body.tags, body.gpu
    )
    audit_service.record(
        session, user=user.username, action="template.save", target=slug, ip=_ip(request)
    )
    return {"id": f"custom:{slug}", "name": body.name}


@router.post("/from-stack")
def save_from_stack(
    body: TemplateFromStackRequest,
    request: Request,
    session: Session = Depends(get_session),
    user: User = Depends(require_admin),
) -> dict:
    if not session.get(Stack, body.stack_id) and not os.path.isdir(
        compose_service.stack_dir(body.stack_id)
    ):
        raise HTTPException(status_code=404, detail=f"Stack '{body.stack_id}' not found")
    slug = template_service.save_from_stack(body.stack_id, body.name, body.description or "")
    audit_service.record(
        session, user=user.username, action="template.save",
        target=slug, detail=body.stack_id, ip=_ip(request),
    )
    return {"id": f"custom:{slug}", "name": body.name}


@router.delete("/custom/{slug}")
def delete_template(
    slug: str,
    request: Request,
    session: Session = Depends(get_session),
    user: User = Depends(require_admin),
) -> dict:
    if not template_service.delete_custom(slug):
        raise HTTPException(status_code=404, detail="Custom template not found")
    audit_service.record(
        session, user=user.username, action="template.delete", target=slug, ip=_ip(request)
    )
    return {"ok": True}


@router.post("/{template_id}/instantiate", status_code=201)
async def instantiate(
    template_id: str,
    body: TemplateInstantiateRequest,
    request: Request,
    session: Session = Depends(get_session),
    user: User = Depends(require_admin),
) -> dict:
    tpl = template_service.get_template(template_id)
    if not tpl:
        raise HTTPException(status_code=404, detail="Template not found")

    # Remote host: agents don't share our filesystem, so ship compose + env.
    if body.agent_id is not None:
        agent = session.get(Agent, body.agent_id)
        if not agent:
            raise HTTPException(status_code=404, detail=f"Agent {body.agent_id} not found")
        try:
            result = await agent_service.call(
                session, agent, "POST", "/agent/stacks",
                json={"name": body.name, "yaml": tpl["compose"], "env": tpl["env"] or None},
            )
        except AgentError as exc:
            raise HTTPException(
                status_code=exc.status if exc.status >= 400 else 502,
                detail={"error": exc.error, "detail": exc.detail},
            )
        audit_service.record(
            session, user=user.username, action="template.instantiate",
            target=f"{agent.name}/{result.get('id')}", detail=template_id, ip=_ip(request),
        )
        return {"id": result.get("id"), "name": body.name, "agent_id": agent.id}

    # Local host: copy the whole template folder into a new stack.
    stack_id = compose_service.slugify(body.name)
    if session.get(Stack, stack_id) or os.path.isdir(compose_service.stack_dir(stack_id)):
        raise HTTPException(status_code=409, detail=f"Stack '{stack_id}' already exists")

    try:
        template_service.copy_into_stack(template_id, stack_id)
    except FileExistsError:
        raise HTTPException(status_code=409, detail=f"Stack '{stack_id}' already exists")
    except FileNotFoundError:
        raise HTTPException(status_code=404, detail="Template not found")

    stack = Stack(id=stack_id, name=body.name, description=tpl.get("description"))
    session.add(stack)
    session.commit()
    audit_service.record(
        session, user=user.username, action="template.instantiate",
        target=stack_id, detail=template_id, ip=_ip(request),
    )
    return {"id": stack_id, "name": body.name, "agent_id": None}