import os
import json
import uuid
from typing import Optional
from datetime import datetime
from fastapi import FastAPI, HTTPException, Path
from pydantic import BaseModel, Field
from filelock import FileLock
import argparse
import uvicorn

app = FastAPI(title="Tour Voting API")

# ─── Pydantic MODELS ──────────────────────────────────────────────────────────

class Idea(BaseModel):
    id: str
    name: str
    start_time: Optional[datetime] = None
    end_time:   Optional[datetime] = None
    description: str
    voters: list[str] = Field(default_factory=list)

class Tour(BaseModel):
    id: str
    name: str
    start_date: Optional[datetime] = None
    end_date:   Optional[datetime] = None
    description: str
    ideas: list[Idea] = Field(default_factory=list)
    createdAt: datetime

class TourCreate(BaseModel):
    name: str
    start_date: Optional[datetime] = None
    end_date:   Optional[datetime] = None
    description: str

class IdeaCreate(BaseModel):
    name: str
    start_time: Optional[datetime] = None
    end_time:   Optional[datetime] = None
    description: str

class Vote(BaseModel):
    voterName: str

# ─── GLOBAL CONFIG ────────────────────────────────────────────────────────────

DATA_DIR = ""  # will be overridden via command line

def get_tour_filepath(tour_id: str) -> str:
    fname = f"{tour_id}.json"
    full = os.path.abspath(os.path.join(DATA_DIR, fname))
    if not full.startswith(os.path.abspath(DATA_DIR) + os.sep):
        raise HTTPException(status_code=400, detail="Invalid tour ID")
    return full

# ─── ENDPOINT: CREATE TOUR ─────────────────────────────────────────────────────

@app.post("/tour/v1/tours", response_model=Tour)
def create_tour(tour: TourCreate):
    """
    Create a new tour. Generates its own UUID and timestamp, then writes to {tour_id}.json.
    """
    tour_id = str(uuid.uuid4())
    created_at = datetime.utcnow()

    new_tour = Tour(
        id=tour_id,
        name=tour.name,
        start_date=tour.start_date,
        end_date=tour.end_date,
        description=tour.description,
        ideas=[],
        createdAt=created_at,
    )

    filepath = get_tour_filepath(tour_id)
    with open(filepath, "w") as f:
        # Using default=str so that datetime objects become ISO strings
        json.dump(new_tour.model_dump(), f, default=str)

    return new_tour

# ─── ENDPOINT: GET TOUR ────────────────────────────────────────────────────────

@app.get("/tour/v1/tours/{tour_id}", response_model=Tour)
def get_tour(tour_id: str = Path(...)):
    """
    Retrieve an existing tour by ID. Loads {tour_id}.json and parses back into a Tour.
    """
    filepath = get_tour_filepath(tour_id)
    if not os.path.exists(filepath):
        raise HTTPException(status_code=404, detail="Tour not found")

    with open(filepath) as f:
        data = json.load(f)

    if data.get("start_date"):
        data["start_date"] = datetime.fromisoformat(data["start_date"])
    if data.get("end_date"):
        data["end_date"] = datetime.fromisoformat(data["end_date"])
    data["createdAt"] = datetime.fromisoformat(data["createdAt"])

    # Convert nested idea timestamps as well
    for idea in data["ideas"]:
        if idea.get("start_time"):
            idea["start_time"] = datetime.fromisoformat(idea["start_time"])
        if idea.get("end_time"):
            idea["end_time"] = datetime.fromisoformat(idea["end_time"])
    return Tour(**data)

# ─── ENDPOINT: ADD IDEA ─────────────────────────────────────────────────────────

@app.post("/tour/v1/tours/{tour_id}/ideas", response_model=Idea)
def add_idea(tour_id: str, idea: IdeaCreate):
    """
    Add a new idea to the given tour. Generates a new UUID for the idea and appends it.
    """
    filepath = get_tour_filepath(tour_id)
    if not os.path.exists(filepath):
        raise HTTPException(status_code=404, detail="Tour not found")

    lock = FileLock(filepath + ".lock")
    with lock:
        with open(filepath) as f:
            data = json.load(f)

        idea_id = str(uuid.uuid4())
        new_idea = Idea(
            id=idea_id,
            name=idea.name,
            description=idea.description,
            voters=[],
            start_time=idea.start_time,
            end_time=idea.end_time,
        )

        data["ideas"].append(new_idea.model_dump())
        with open(filepath, "w") as f:
            json.dump(data, f, default=str)

    return new_idea

# ─── ENDPOINT: VOTE FOR IDEA ───────────────────────────────────────────────────

@app.post("/tour/v1/tours/{tour_id}/ideas/{idea_id}/vote", response_model=Idea)
def vote_idea(tour_id: str, idea_id: str, vote: Vote):
    """
    Cast a vote on a specific idea. Adds voterName if not already present.
    """
    filepath = get_tour_filepath(tour_id)
    if not os.path.exists(filepath):
        raise HTTPException(status_code=404, detail="Tour not found")

    lock = FileLock(filepath + ".lock")
    with lock:
        with open(filepath) as f:
            data = json.load(f)

        for idea in data["ideas"]:
            if idea["id"] == idea_id:
                if vote.voterName not in idea["voters"]:
                    idea["voters"].append(vote.voterName)
                    # Persist the change
                    with open(filepath, "w") as f:
                        json.dump(data, f, default=str)
                return Idea(**idea)

    raise HTTPException(status_code=404, detail="Idea not found")

# ─── MAIN: RUN UVIDORN WITH COMMAND-LINE DATA DIR ──────────────────────────────

if __name__ == "__main__":
    parser = argparse.ArgumentParser(description="Run Tour Voting API server")
    parser.add_argument(
        "--data-dir",
        required=True,
        help="Directory in which to store tour JSON files (one file per tour_id)",
    )
    parser.add_argument(
        "--host",
        default="0.0.0.0",
        help="Host to run the server on",
    )
    parser.add_argument(
        "--port",
        type=int,
        default=8000,
        help="Port to run the server on",
    )
    args = parser.parse_args()

    DATA_DIR = args.data_dir
    os.makedirs(DATA_DIR, exist_ok=True)

    uvicorn.run(app, host=args.host, port=args.port, reload=False)