from fastapi import FastAPI, HTTPException, Depends
from sqlalchemy import create_engine, Column, Integer, String, Boolean, text
from sqlalchemy.orm import declarative_base, Session, sessionmaker
from pydantic import BaseModel
from typing import Optional
import os
import time
import logging

logging.basicConfig(level=logging.INFO)
log = logging.getLogger(__name__)

# ── Database connection ───────────────────────────────────────────────────────
DB_HOST = os.getenv("DATABASE_HOST", "localhost")
DB_PORT = os.getenv("DATABASE_PORT", "5432")
DB_USER = os.getenv("POSTGRES_USER", "fastapiuser")
DB_PASS = os.getenv("POSTGRES_PASSWORD", "student123")
DB_NAME = os.getenv("POSTGRES_DB", "fastapidb")

DATABASE_URL = f"postgresql://{DB_USER}:{DB_PASS}@{DB_HOST}:{DB_PORT}/{DB_NAME}"

# Retry logic — baza mozda nije odmah dostupna kad Pod starta
engine = None
for attempt in range(10):
    try:
        engine = create_engine(DATABASE_URL)
        with engine.connect() as conn:
            conn.execute(text("SELECT 1"))
        log.info(f"Baza dostupna (pokusaj {attempt + 1})")
        break
    except Exception as e:
        log.warning(f"Baza nije dostupna, cekam 3s... (pokusaj {attempt + 1}): {e}")
        time.sleep(3)

if engine is None:
    raise RuntimeError("Ne mogu se spojiti na bazu nakon 10 pokusaja")

SessionLocal = sessionmaker(bind=engine)
Base = declarative_base()

# ── Model ─────────────────────────────────────────────────────────────────────
class Todo(Base):
    __tablename__ = "todos"
    id       = Column(Integer, primary_key=True, index=True)
    title    = Column(String(200), nullable=False)
    done     = Column(Boolean, default=False)

Base.metadata.create_all(bind=engine)

# ── Schemas ───────────────────────────────────────────────────────────────────
class TodoCreate(BaseModel):
    title: str
    done:  Optional[bool] = False

class TodoUpdate(BaseModel):
    title: Optional[str] = None
    done:  Optional[bool] = None

class TodoOut(BaseModel):
    id:    int
    title: str
    done:  bool

    model_config = {"from_attributes": True}

# ── App ───────────────────────────────────────────────────────────────────────
app = FastAPI(title="FastAPI Todo API", version="1.0.0")

def get_db():
    db = SessionLocal()
    try:
        yield db
    finally:
        db.close()

# ── Routes ────────────────────────────────────────────────────────────────────
@app.get("/health")
def health():
    try:
        with engine.connect() as conn:
            conn.execute(text("SELECT 1"))
        return {"status": "ok", "database": "connected"}
    except Exception as e:
        raise HTTPException(status_code=503, detail=f"Baza nedostupna: {e}")

@app.get("/todos", response_model=list[TodoOut])
def get_todos(db: Session = Depends(get_db)):
    return db.query(Todo).all()

@app.get("/todos/{todo_id}", response_model=TodoOut)
def get_todo(todo_id: int, db: Session = Depends(get_db)):
    todo = db.query(Todo).filter(Todo.id == todo_id).first()
    if not todo:
        raise HTTPException(status_code=404, detail="Todo nije pronaden")
    return todo

@app.post("/todos", response_model=TodoOut, status_code=201)
def create_todo(payload: TodoCreate, db: Session = Depends(get_db)):
    todo = Todo(title=payload.title, done=payload.done)
    db.add(todo)
    db.commit()
    db.refresh(todo)
    return todo

@app.put("/todos/{todo_id}", response_model=TodoOut)
def update_todo(todo_id: int, payload: TodoUpdate, db: Session = Depends(get_db)):
    todo = db.query(Todo).filter(Todo.id == todo_id).first()
    if not todo:
        raise HTTPException(status_code=404, detail="Todo nije pronaden")
    if payload.title is not None:
        todo.title = payload.title
    if payload.done is not None:
        todo.done = payload.done
    db.commit()
    db.refresh(todo)
    return todo

@app.delete("/todos/{todo_id}")
def delete_todo(todo_id: int, db: Session = Depends(get_db)):
    todo = db.query(Todo).filter(Todo.id == todo_id).first()
    if not todo:
        raise HTTPException(status_code=404, detail="Todo nije pronaden")
    db.delete(todo)
    db.commit()
    return {"message": f"Todo {todo_id} obrisan"}