from fastapi import FastAPI, Depends, HTTPException, Query
from fastapi.middleware.cors import CORSMiddleware
import uvicorn
from typing import List, Optional
from sqlalchemy.orm import Session
from sqlalchemy import or_, and_, func
from datetime import datetime, timedelta

from app.database import get_db, engine
from app.models import Todo, Tag, Subtask, TodoBoard, Base, BoardStatus
from app.schemas import (
    TodoCreate, TodoCreateWithTags, TodoUpdate, TodoResponse,
    TagCreate, TagResponse, HealthResponse,
    SubtaskCreate, SubtaskUpdate, SubtaskResponse,
    TodoBoardCreate, TodoBoardUpdate, TodoBoardResponse, TodoBoardDetailResponse
)

# Create tables if they don't exist
Base.metadata.create_all(bind=engine)

app = FastAPI(
    title="Enhanced Todo API",
    description="An improved API for managing todos with tags, priority levels, due dates, and search functionality",
    version="0.2.0",
)

app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

@app.get("/health", response_model=HealthResponse)
def health():
    return {"status": "healthy"}

# Tag endpoints
@app.post("/tags/", response_model=TagResponse)
def create_tag(tag: TagCreate, db: Session = Depends(get_db)):
    # Check if tag already exists
    existing_tag = db.query(Tag).filter(Tag.name == tag.name).first()
    if existing_tag:
        return existing_tag

    db_tag = Tag(**tag.model_dump())
    db.add(db_tag)
    db.commit()
    db.refresh(db_tag)
    return db_tag

@app.get("/tags/", response_model=List[TagResponse])
def get_tags(skip: int = 0, limit: int = 100, db: Session = Depends(get_db)):
    return db.query(Tag).offset(skip).limit(limit).all()

@app.get("/tags/{tag_id}", response_model=TagResponse)
def get_tag(tag_id: int, db: Session = Depends(get_db)):
    db_tag = db.query(Tag).filter(Tag.id == tag_id).first()
    if db_tag is None:
        raise HTTPException(status_code=404, detail="Tag not found")
    return db_tag

# Todo endpoints
@app.post("/todos/", response_model=TodoResponse)
def create_todo(todo: TodoCreate, db: Session = Depends(get_db)):
    todo_data = todo.model_dump(exclude={"tag_ids"})
    db_todo = Todo(**todo_data)

    # Add tags if provided
    if todo.tag_ids:
        for tag_id in todo.tag_ids:
            tag = db.query(Tag).filter(Tag.id == tag_id).first()
            if tag is None:
                raise HTTPException(status_code=404, detail=f"Tag with id {tag_id} not found")
            db_todo.tags.append(tag)

    db.add(db_todo)
    db.commit()
    db.refresh(db_todo)
    return db_todo

@app.post("/todos/with-tags/", response_model=TodoResponse)
def create_todo_with_tags(todo: TodoCreateWithTags, db: Session = Depends(get_db)):
    # Extract and create todo
    todo_data = todo.model_dump(exclude={"tags"})
    db_todo = Todo(**todo_data)

    # Process tags
    if todo.tags:
        for tag_name in todo.tags:
            # Find existing tag or create new one
            tag = db.query(Tag).filter(Tag.name == tag_name).first()
            if not tag:
                tag = Tag(name=tag_name)
                db.add(tag)
                db.flush()
            db_todo.tags.append(tag)

    db.add(db_todo)
    db.commit()
    db.refresh(db_todo)
    return db_todo

@app.get("/todos/", response_model=List[TodoResponse])
def get_todos(
    skip: int = 0,
    limit: int = 100,
    title: Optional[str] = None,
    description: Optional[str] = None,
    completed: Optional[bool] = None,
    priority: Optional[str] = None,
    tag: Optional[str] = None,
    due_before: Optional[datetime] = None,
    due_after: Optional[datetime] = None,
    overdue: Optional[bool] = None,
    db: Session = Depends(get_db)
):
    query = db.query(Todo)

    # Apply filters if provided
    if title:
        query = query.filter(Todo.title.ilike(f"%{title}%"))
    if description:
        query = query.filter(Todo.description.ilike(f"%{description}%"))
    if completed is not None:
        query = query.filter(Todo.completed == completed)
    if priority:
        query = query.filter(Todo.priority == priority)
    if tag:
        query = query.join(Todo.tags).filter(Tag.name == tag)
    if due_before:
        query = query.filter(Todo.due_date <= due_before)
    if due_after:
        query = query.filter(Todo.due_date >= due_after)
    if overdue is not None and overdue:
        query = query.filter(and_(
            Todo.due_date < datetime.now(),
            Todo.completed == False
        ))

    return query.offset(skip).limit(limit).all()

@app.get("/todos/search/", response_model=List[TodoResponse])
def search_todos(
    q: str = Query(..., min_length=1, description="Search query"),
    db: Session = Depends(get_db)
):
    """Search todos by title, description or tag name"""
    return db.query(Todo).filter(
        or_(
            Todo.title.ilike(f"%{q}%"),
            Todo.description.ilike(f"%{q}%"),
            Todo.tags.any(Tag.name.ilike(f"%{q}%"))
        )
    ).all()

@app.get("/todos/upcoming/", response_model=List[TodoResponse])
def get_upcoming_todos(days: int = 7, db: Session = Depends(get_db)):
    """Get todos with due dates in the next N days"""
    future_date = datetime.now() + timedelta(days=days)
    return db.query(Todo).filter(
        and_(
            Todo.due_date <= future_date,
            Todo.due_date >= datetime.now(),
            Todo.completed == False
        )
    ).order_by(Todo.due_date).all()

@app.get("/todos/reminders/", response_model=List[TodoResponse])
def get_upcoming_reminders(hours: int = 24, db: Session = Depends(get_db)):
    """Get todos with reminders in the next N hours"""
    now = datetime.now()
    future_time = now + timedelta(hours=hours)

    return db.query(Todo).filter(
        and_(
            Todo.remind_at <= future_time,
            Todo.remind_at >= now,
            Todo.completed == False
        )
    ).order_by(Todo.remind_at).all()

@app.put("/todos/{todo_id}/set-reminder", response_model=TodoResponse)
def set_reminder(todo_id: int, remind_at: datetime, db: Session = Depends(get_db)):
    """Set or update a reminder for a specific todo"""
    db_todo = db.query(Todo).filter(Todo.id == todo_id).first()
    if db_todo is None:
        raise HTTPException(status_code=404, detail="Todo not found")

    db_todo.remind_at = remind_at
    db.commit()
    db.refresh(db_todo)
    return db_todo

@app.get("/todos/{todo_id}", response_model=TodoResponse)
def get_todo(todo_id: int, db: Session = Depends(get_db)):
    db_todo = db.query(Todo).filter(Todo.id == todo_id).first()
    if db_todo is None:
        raise HTTPException(status_code=404, detail="Todo not found")
    return db_todo

@app.put("/todos/{todo_id}", response_model=TodoResponse)
def update_todo(todo_id: int, todo: TodoUpdate, db: Session = Depends(get_db)):
    db_todo = db.query(Todo).filter(Todo.id == todo_id).first()
    if db_todo is None:
        raise HTTPException(status_code=404, detail="Todo not found")

    # Update todo attributes
    todo_data = todo.model_dump(exclude={"tag_ids"}, exclude_unset=True)
    for key, value in todo_data.items():
        setattr(db_todo, key, value)

    # Update tags if provided
    if todo.tag_ids is not None:
        # Clear existing tags
        db_todo.tags = []
        # Add new tags
        for tag_id in todo.tag_ids:
            tag = db.query(Tag).filter(Tag.id == tag_id).first()
            if tag is None:
                raise HTTPException(status_code=404, detail=f"Tag with id {tag_id} not found")
            db_todo.tags.append(tag)

    db.commit()
    db.refresh(db_todo)
    return db_todo

@app.delete("/todos/{todo_id}", response_model=TodoResponse)
def delete_todo(todo_id: int, db: Session = Depends(get_db)):
    db_todo = db.query(Todo).filter(Todo.id == todo_id).first()
    if db_todo is None:
        raise HTTPException(status_code=404, detail="Todo not found")

    db.delete(db_todo)
    db.commit()
    return db_todo

# Subtasks endpoints
@app.post("/todos/{todo_id}/subtasks/", response_model=SubtaskResponse)
def create_subtask(todo_id: int, subtask: SubtaskCreate, db: Session = Depends(get_db)):
    """Create a new subtask for a specific todo"""
    db_todo = db.query(Todo).filter(Todo.id == todo_id).first()
    if db_todo is None:
        raise HTTPException(status_code=404, detail="Todo not found")

    db_subtask = Subtask(**subtask.model_dump(), todo_id=todo_id)
    db.add(db_subtask)
    db.commit()
    db.refresh(db_subtask)
    return db_subtask

@app.get("/todos/{todo_id}/subtasks/", response_model=List[SubtaskResponse])
def get_subtasks(todo_id: int, skip: int = 0, limit: int = 100, db: Session = Depends(get_db)):
    """Get all subtasks for a todo"""
    db_todo = db.query(Todo).filter(Todo.id == todo_id).first()
    if db_todo is None:
        raise HTTPException(status_code=404, detail="Todo not found")

    return db.query(Subtask).filter(Subtask.todo_id == todo_id).offset(skip).limit(limit).all()

@app.get("/subtasks/{subtask_id}", response_model=SubtaskResponse)
def get_subtask(subtask_id: int, db: Session = Depends(get_db)):
    """Get a specific subtask by ID"""
    db_subtask = db.query(Subtask).filter(Subtask.id == subtask_id).first()
    if db_subtask is None:
        raise HTTPException(status_code=404, detail="Subtask not found")
    return db_subtask

@app.put("/subtasks/{subtask_id}", response_model=SubtaskResponse)
def update_subtask(subtask_id: int, subtask: SubtaskUpdate, db: Session = Depends(get_db)):
    """Update a specific subtask"""
    db_subtask = db.query(Subtask).filter(Subtask.id == subtask_id).first()
    if db_subtask is None:
        raise HTTPException(status_code=404, detail="Subtask not found")

    subtask_data = subtask.model_dump(exclude_unset=True)
    for key, value in subtask_data.items():
        setattr(db_subtask, key, value)

    db.commit()
    db.refresh(db_subtask)
    return db_subtask

@app.delete("/subtasks/{subtask_id}", response_model=SubtaskResponse)
def delete_subtask(subtask_id: int, db: Session = Depends(get_db)):
    """Delete a specific subtask"""
    db_subtask = db.query(Subtask).filter(Subtask.id == subtask_id).first()
    if db_subtask is None:
        raise HTTPException(status_code=404, detail="Subtask not found")

    db.delete(db_subtask)
    db.commit()
    return db_subtask

@app.put("/todos/{todo_id}/complete-all-subtasks", response_model=TodoResponse)
def complete_all_subtasks(todo_id: int, db: Session = Depends(get_db)):
    """Mark all subtasks of a todo as completed"""
    db_todo = db.query(Todo).filter(Todo.id == todo_id).first()
    if db_todo is None:
        raise HTTPException(status_code=404, detail="Todo not found")

    db.query(Subtask).filter(Subtask.todo_id == todo_id).update({"completed": True})
    db.commit()
    db.refresh(db_todo)
    return db_todo

# TodoBoard endpoints
@app.post("/boards/", response_model=TodoBoardResponse)
def create_board(board: TodoBoardCreate, db: Session = Depends(get_db)):
    """Create a new todo board"""
    db_board = TodoBoard(**board.model_dump())
    db.add(db_board)
    db.commit()
    db.refresh(db_board)
    return db_board

@app.get("/boards/", response_model=List[TodoBoardResponse])
def get_boards(skip: int = 0, limit: int = 100, db: Session = Depends(get_db)):
    """Get all todo boards"""
    return db.query(TodoBoard).offset(skip).limit(limit).all()

@app.get("/boards/{board_id}", response_model=TodoBoardDetailResponse)
def get_board(board_id: int, db: Session = Depends(get_db)):
    """Get a specific todo board with all its todos"""
    db_board = db.query(TodoBoard).filter(TodoBoard.id == board_id).first()
    if db_board is None:
        raise HTTPException(status_code=404, detail="Board not found")
    return db_board

@app.put("/boards/{board_id}", response_model=TodoBoardResponse)
def update_board(board_id: int, board: TodoBoardUpdate, db: Session = Depends(get_db)):
    """Update a specific todo board"""
    db_board = db.query(TodoBoard).filter(TodoBoard.id == board_id).first()
    if db_board is None:
        raise HTTPException(status_code=404, detail="Board not found")

    board_data = board.model_dump(exclude_unset=True)
    for key, value in board_data.items():
        setattr(db_board, key, value)

    db.commit()
    db.refresh(db_board)
    return db_board

@app.delete("/boards/{board_id}", response_model=TodoBoardResponse)
def delete_board(board_id: int, db: Session = Depends(get_db)):
    """Delete a specific todo board"""
    db_board = db.query(TodoBoard).filter(TodoBoard.id == board_id).first()
    if db_board is None:
        raise HTTPException(status_code=404, detail="Board not found")

    db.delete(db_board)
    db.commit()
    return db_board

@app.post("/boards/{board_id}/todos/", response_model=TodoResponse)
def create_todo_in_board(board_id: int, todo: TodoCreate, db: Session = Depends(get_db)):
    """Create a new todo in a specific board"""
    db_board = db.query(TodoBoard).filter(TodoBoard.id == board_id).first()
    if db_board is None:
        raise HTTPException(status_code=404, detail="Board not found")

    todo_data = todo.model_dump(exclude={"tag_ids", "board_id"})
    db_todo = Todo(**todo_data, board_id=board_id)

    # Add tags if provided
    if todo.tag_ids:
        for tag_id in todo.tag_ids:
            tag = db.query(Tag).filter(Tag.id == tag_id).first()
            if tag is None:
                raise HTTPException(status_code=404, detail=f"Tag with id {tag_id} not found")
            db_todo.tags.append(tag)

    db.add(db_todo)
    db.commit()
    db.refresh(db_todo)
    return db_todo

@app.get("/boards/{board_id}/todos/", response_model=List[TodoResponse])
def get_todos_by_board(
    board_id: int,
    status: Optional[BoardStatus] = None,
    skip: int = 0,
    limit: int = 100,
    db: Session = Depends(get_db)
):
    """Get all todos in a specific board with optional status filter"""
    db_board = db.query(TodoBoard).filter(TodoBoard.id == board_id).first()
    if db_board is None:
        raise HTTPException(status_code=404, detail="Board not found")

    query = db.query(Todo).filter(Todo.board_id == board_id)

    if status:
        query = query.filter(Todo.status == status)

    return query.offset(skip).limit(limit).all()

@app.put("/todos/{todo_id}/move", response_model=TodoResponse)
def move_todo_to_board(
    todo_id: int,
    board_id: Optional[int] = None,
    status: Optional[BoardStatus] = None,
    db: Session = Depends(get_db)
):
    """Move a todo to a different board and/or change its status"""
    db_todo = db.query(Todo).filter(Todo.id == todo_id).first()
    if db_todo is None:
        raise HTTPException(status_code=404, detail="Todo not found")

    if board_id is not None:
        # Verify board exists
        db_board = db.query(TodoBoard).filter(TodoBoard.id == board_id).first()
        if db_board is None:
            raise HTTPException(status_code=404, detail="Board not found")
        db_todo.board_id = board_id

    if status is not None:
        db_todo.status = status

    db.commit()
    db.refresh(db_todo)
    return db_todo

if __name__ == "__main__":
    uvicorn.run("main:app", host="0.0.0.0", port=8000, reload=True)