from flask import Blueprint, current_app, jsonify, redirect, request
from app.state import load_state, save_state

bp = Blueprint("nav", __name__)

STALE_DOWNSTREAM = {
    "triage": ["curate", "group", "write"],
    "curate": ["group", "write"],
    "group": ["write"],
    "write": [],
    "export": [],
}


@bp.post("/nav/phase")
def goto_phase():
    body = request.get_json()
    target = body["target_phase"]
    state = load_state(body["album_id"], current_app)
    if state is None:
        return jsonify({"error": "no state"}), 404

    # Mark downstream completed phases and the current phase as stale
    downstream = STALE_DOWNSTREAM.get(target, [])
    candidates = set(downstream) & (set(state.phases_completed) | {state.phase})
    newly_stale = [p for p in candidates if p not in state.phase_stale]
    state.phase_stale = list(set(state.phase_stale + newly_stale))
    state.phase = target
    save_state(state, current_app)
    return jsonify({"ok": True, "phase": target})


@bp.post("/nav/dismiss-stale")
def dismiss_stale():
    album_id = request.form["album_id"]
    phase = request.form["phase"]
    state = load_state(album_id, current_app)
    if state:
        state.phase_stale = [p for p in state.phase_stale if p != phase]
        save_state(state, current_app)
    return redirect(f"/{phase}?album_id={album_id}")


@bp.get("/state/<album_id>")
def get_state(album_id):
    """Debug/test endpoint — returns full state JSON."""
    state = load_state(album_id, current_app)
    if state is None:
        return jsonify({"error": "no state"}), 404
    from dataclasses import asdict
    return jsonify(asdict(state))