import json
import os
from dataclasses import dataclass, field, asdict
from pathlib import Path
from typing import Optional

from flask import current_app


@dataclass
class Photo:
    id: str
    original_filename: str
    local_datetime: str
    tag: str = "untagged"   # untagged | journal | story | skip
    order: int = 0


@dataclass
class Group:
    id: str
    photo_ids: list = field(default_factory=list)
    entry_type: str = "journal"   # journal | story
    title: str = ""
    body: str = ""
    location_city: str = ""
    location_country: str = ""
    date: str = ""
    hero_photo_id: Optional[str] = None
    shortcode_hints: str = ""
    status: str = "draft"   # draft | written | skipped | exported


@dataclass
class TripState:
    album_id: str
    album_name: str
    grav_trip_slug: str
    phase: str = "triage"
    phases_completed: list = field(default_factory=list)
    phase_stale: list = field(default_factory=list)
    photos: list = field(default_factory=list)
    groups: list = field(default_factory=list)
    notes: str = ""


def _state_path(album_id: str, app) -> Path:
    return Path(app.config["STATE_DIR"]) / f"{album_id}.json"


def load_state(album_id: str, app) -> Optional[TripState]:
    path = _state_path(album_id, app)
    if not path.exists():
        return None
    with open(path) as f:
        data = json.load(f)
    photos = [Photo(**p) for p in data.pop("photos", [])]
    groups = [Group(**g) for g in data.pop("groups", [])]
    return TripState(photos=photos, groups=groups, **data)


def save_state(state: TripState, app) -> None:
    path = _state_path(state.album_id, app)
    path.parent.mkdir(parents=True, exist_ok=True)
    tmp = path.with_suffix(".tmp")
    with open(tmp, "w") as f:
        json.dump(asdict(state), f, indent=2)
    os.rename(tmp, path)