"""Global constants and initial session-state defaults."""
from typing import List
import pandas as pd

FREQUENCIES: List[int] = [125, 250, 500, 1000, 2000, 4000]
TOTAL_DOTS = 200
AI_BANDS = {
    (0.00, 0.24): "None",
    (0.25, 0.40): "Fair",
    (0.41, 0.60): "Good",
    (0.61, 1.00): "Excellent",
}
MAJOR_TABS = [
    "Instructions",
    "Initial Data Entry",
    "Initial Compliance Checks",
    "Acoustic Treatment",
    "Final Compliance Checks",
    "FAQ / Help",
]

# ── Streamlit-session defaults ────────────────────────────────────────────
DEFAULTS = dict(
    major_tab=MAJOR_TABS[0],
    # uploads / inputs
    df_current_rt=None, df_existing_mat=None, room_volume=0.0,
    df_background_noise=pd.DataFrame(columns=["Location", "dBA"]),
    bn_input_loc="", bn_input_val=0.0,
    df_spl=None,
    # compliance params
    rt_min=0.0, rt_max=0.0, bn_min=0.0, bn_max=0.0,
    # multi-location AI dictionaries
    dots_init_dict={}, ai_init_dict={},
    dots_final_dict={}, ai_final_dict={},
    # acoustic-treatment data
    desired_rt_df=pd.DataFrame(
        {"Frequency": FREQUENCIES, "Desired RT60": [0.01]*6}
    ),
    df_new_mat=None,
    # derived absorption & figures
    current_absorption={}, new_absorption={},
    fig_rt_initial=None, fig_bn_initial=None,
    fig_rt_final=None,  fig_bn_final=None,
)