"""DataTools Column Mapper — stub page."""

from __future__ import annotations

import sys
from pathlib import Path

import streamlit as st

_project_root = Path(__file__).resolve().parent.parent.parent.parent
if str(_project_root) not in sys.path:
    sys.path.insert(0, str(_project_root))

from src.gui.components import hide_streamlit_chrome

hide_streamlit_chrome()

# ---------------------------------------------------------------------------
# Header
# ---------------------------------------------------------------------------

st.title("🗂️ Column Mapper")
st.caption("Rename columns, enforce a target schema, and coerce types.")

st.info("This tool is under development.")

# ---------------------------------------------------------------------------
# What this tool will do
# ---------------------------------------------------------------------------

st.markdown("""
**Features:**
- Rename columns via interactive mapping table
- Load a target schema (JSON/CSV) to auto-map columns
- Fuzzy column name matching for automatic suggestions
- Type coercion (string → int, string → date, etc.)
- Drop unmapped columns or keep as-is
- Reorder columns to match target schema
""")

st.divider()

# ---------------------------------------------------------------------------
# File upload (functional)
# ---------------------------------------------------------------------------

uploaded = st.file_uploader(
    "Upload CSV or Excel file",
    type=["csv", "tsv", "xlsx", "xls"],
    help="Upload a file to preview. Processing is not yet available.",
    key="colmap_file_upload",
)

if uploaded is not None:
    import pandas as pd
    try:
        if uploaded.name.endswith((".xlsx", ".xls")):
            df = pd.read_excel(uploaded)
        else:
            df = pd.read_csv(uploaded)
        st.subheader(f"Preview: {uploaded.name}")
        st.caption(f"{len(df)} rows, {len(df.columns)} columns")
        st.dataframe(df.head(10), use_container_width=True)

        st.subheader("Column Mapping")
        st.caption("Map source columns to target names. (Interactive mapping coming soon.)")
        mapping_data = pd.DataFrame({
            "Source Column": df.columns.tolist(),
            "Target Column": df.columns.tolist(),
            "Type": ["auto"] * len(df.columns),
        })
        st.dataframe(mapping_data, use_container_width=True, hide_index=True)
    except Exception as e:
        st.error(f"Failed to read file: {e}")

# ---------------------------------------------------------------------------
# Placeholder options
# ---------------------------------------------------------------------------

st.subheader("Schema Options")

st.file_uploader("Load target schema (JSON)", type=["json"], disabled=True, key="colmap_schema")
st.checkbox("Drop unmapped columns", value=False, disabled=True)
st.checkbox("Reorder to match schema", value=True, disabled=True)

st.divider()
st.button("Apply Column Mapping", type="primary", use_container_width=True, disabled=True)

# ---------------------------------------------------------------------------
# Footer
# ---------------------------------------------------------------------------

st.divider()
st.caption(
    "Runs locally. Your data never leaves this computer. "
    "| DataTools v3.0"
)