from __future__ import annotations

import os

import requests
import yaml
from fastapi import Depends, FastAPI, HTTPException
from pydantic import BaseModel
from sqlalchemy import select
from sqlalchemy.orm import Session
from sqlalchemy.exc import SQLAlchemyError

app = FastAPI(title="AI CI/CD Assistant")


def _env(name: str, default: str) -> str:
    value = os.getenv(name)
    return value if value else default


# Example for local Ollama: http://localhost:11434/api/generate
OLLAMA_API_URL = _env("OLLAMA_API_URL", "http://host.docker.internal:11434/api/generate")
REQUIRE_AUTH_FOR_GENERATE = _env("REQUIRE_AUTH_FOR_GENERATE", "true").lower() in ("1", "true", "yes", "on")

from backend.auth import create_access_token, get_current_user, hash_password, verify_password  # noqa: E402
from backend.db import engine, get_db  # noqa: E402
from backend.models import Base, User  # noqa: E402


def _password_ok_or_400(password: str):
    # bcrypt has a 72-byte input limit (bytes, not chars)
    if len(password.encode("utf-8")) > 72:
        raise HTTPException(status_code=400, detail="Password is too long (max 72 bytes for bcrypt)")


class GenerationRequest(BaseModel):
    description: str
    platform: str = "GitHub Actions"  # or GitLab CI
    model: str = "codellama"


def validate_config(config_text: str):
    try:
        yaml.safe_load(config_text)
        return True, "Success"
    except Exception as e:
        return False, str(e)


@app.get("/health")
async def health():
    # lightweight DB probe to surface connection issues early
    db_ok = True
    db_error = None
    try:
        with engine.connect() as conn:
            conn.exec_driver_sql("SELECT 1")
    except Exception as e:
        db_ok = False
        db_error = str(e)
    return {"status": "ok", "db_ok": db_ok, "db_error": db_error}


@app.on_event("startup")
def _startup():
    # Ensure tables exist; if DB is unreachable, endpoints will surface the error.
    try:
        Base.metadata.create_all(bind=engine)
    except Exception:
        # Avoid crashing the service hard; /health will show db_error.
        pass


class RegisterRequest(BaseModel):
    email: str
    password: str
    full_name: str | None = None


class LoginRequest(BaseModel):
    email: str
    password: str


@app.post("/auth/register")
def register(req: RegisterRequest, db: Session = Depends(get_db)):
    email = req.email.strip().lower()
    if not email or not req.password:
        raise HTTPException(status_code=400, detail="Email and password are required")
    _password_ok_or_400(req.password)

    try:
        exists = db.execute(select(User).where(User.email == email)).scalar_one_or_none()
        if exists:
            raise HTTPException(status_code=409, detail="Email already registered")

        user = User(
            email=email,
            full_name=req.full_name.strip() if req.full_name else None,
            password_hash=hash_password(req.password),
            is_active=True,
            is_admin=False,
        )
        db.add(user)
        db.commit()
        db.refresh(user)
        return {"id": str(user.id), "email": user.email, "full_name": user.full_name, "is_admin": user.is_admin}
    except HTTPException:
        raise
    except SQLAlchemyError as e:
        db.rollback()
        raise HTTPException(status_code=500, detail=f"Database error: {str(e)}")
    except Exception as e:
        db.rollback()
        raise HTTPException(status_code=500, detail=f"Internal error: {str(e)}")


@app.post("/auth/login")
def login(req: LoginRequest, db: Session = Depends(get_db)):
    email = req.email.strip().lower()
    if not req.password:
        raise HTTPException(status_code=400, detail="Password is required")
    _password_ok_or_400(req.password)
    try:
        user = db.execute(select(User).where(User.email == email)).scalar_one_or_none()
        if not user or not verify_password(req.password, user.password_hash):
            raise HTTPException(status_code=401, detail="Invalid credentials")
        if not user.is_active:
            raise HTTPException(status_code=403, detail="User is inactive")

        token = create_access_token(user_id=str(user.id))
        return {"access_token": token, "token_type": "bearer"}
    except HTTPException:
        raise
    except SQLAlchemyError as e:
        raise HTTPException(status_code=500, detail=f"Database error: {str(e)}")
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"Internal error: {str(e)}")


@app.get("/auth/me")
def me(user: User = Depends(get_current_user)):
    return {"id": str(user.id), "email": user.email, "full_name": user.full_name, "is_admin": user.is_admin}


@app.post("/generate")
async def generate_pipeline(
    req: GenerationRequest,
    user: User | None = Depends(get_current_user) if REQUIRE_AUTH_FOR_GENERATE else None,
):
    prompt = (
        f"Write only a valid {req.platform} YAML configuration for: {req.description}. "
        "No explanations, just code."
    )

    payload = {"model": req.model, "prompt": prompt, "stream": False}

    try:
        response = requests.post(OLLAMA_API_URL, json=payload, timeout=60)
        response.raise_for_status()
        raw_text = response.json().get("response", "")

        clean_code = raw_text.replace("```yaml", "").replace("```", "").strip()
        is_valid, error_msg = validate_config(clean_code)

        return {
            "status": "ok" if is_valid else "error",
            "config": clean_code,
            "validation_error": error_msg if not is_valid else None,
        }
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"Ollama error: {str(e)}")


if __name__ == "__main__":
    import uvicorn

    uvicorn.run(app, host="0.0.0.0", port=int(_env("PORT", "8000")))