# pages/99_File_Explorer.py
# -------------------------------------------------------------------
# Universal File Explorer for the /data directory (and subfolders).
# Allows browsing, viewing JSON/Markdown/text, and downloading files.
# -------------------------------------------------------------------

from __future__ import annotations
import os
import json
import mimetypes
from pathlib import Path
import streamlit as st

# --- Page setup ---
st.set_page_config(page_title="File Explorer", page_icon="📁", layout="wide")
st.title("📁 File Explorer")
st.caption("Browse and download files under the /data directory (e.g., cases, exports, FAISS indexes, etc.)")

# --- Root directory (default /data) ---
ROOT_DIR = Path("/data")
if not ROOT_DIR.exists():
    st.error("⚠️ /data directory not found in this environment.")
    st.stop()

# --- Utility functions ---
def list_dir(path: Path):
    """Return a sorted list of (name, is_dir) tuples."""
    items = []
    for entry in sorted(os.listdir(path)):
        p = path / entry
        if entry.startswith("."):  # hide hidden files
            continue
        items.append((entry, p.is_dir()))
    return items

def render_file(path: Path):
    """Render or offer download for the selected file."""
    mime, _ = mimetypes.guess_type(str(path))
    st.markdown(f"**Path:** `{path}`  \n**Size:** {path.stat().st_size:,} bytes")
    if path.suffix.lower() in [".json", ".md", ".txt", ".log"]:
        try:
            text = path.read_text(encoding="utf-8")
            if path.suffix.lower() == ".json":
                st.json(json.loads(text))
            elif path.suffix.lower() == ".md":
                st.markdown(text)
            else:
                st.code(text)
        except Exception as e:
            st.error(f"Error reading file: {e}")
    else:
        with open(path, "rb") as f:
            st.download_button(
                label="⬇️ Download File",
                data=f,
                file_name=path.name,
                mime=mime or "application/octet-stream",
                use_container_width=True,
            )

def export_metadata_tree(root: Path) -> dict:
    """Recursively export metadata (name, size, type, children)."""
    tree = {"name": root.name, "path": str(root), "type": "directory" if root.is_dir() else "file"}
    if root.is_dir():
        children = []
        for entry in sorted(os.listdir(root)):
            p = root / entry
            if entry.startswith("."):
                continue
            children.append(export_metadata_tree(p))
        tree["children"] = children
    else:
        try:
            tree["size"] = root.stat().st_size
        except Exception:
            tree["size"] = None
    return tree

# --- Sidebar navigation ---
st.sidebar.header("📂 Directory Browser")

def browse(path: Path):
    st.sidebar.markdown(f"**Current:** `{path}`")
    items = list_dir(path)
    for name, is_dir in items:
        sub_path = path / name
        if is_dir:
            if st.sidebar.button(f"📁 {name}", key=str(sub_path)):
                st.session_state["explorer_path"] = str(sub_path)
        else:
            if st.sidebar.button(f"📄 {name}", key=str(sub_path)):
                st.session_state["selected_file"] = str(sub_path)

# --- Manage navigation state ---
if "explorer_path" not in st.session_state:
    st.session_state["explorer_path"] = str(ROOT_DIR)
if "selected_file" not in st.session_state:
    st.session_state["selected_file"] = ""

current_path = Path(st.session_state["explorer_path"])
browse(current_path)

# --- Main view ---
st.divider()
st.markdown(f"### 📂 {current_path}")

if st.button("⬆️ Up one level", use_container_width=False):
    if current_path != ROOT_DIR:
        st.session_state["explorer_path"] = str(current_path.parent)
        st.session_state["selected_file"] = ""
        st.rerun()

# --- Show directory contents ---
entries = list_dir(current_path)
for name, is_dir in entries:
    p = current_path / name
    icon = "📁" if is_dir else "📄"
    st.write(f"{icon} `{name}`")

st.divider()

# --- Show selected file (if any) ---
selected_path = Path(st.session_state["selected_file"]) if st.session_state["selected_file"] else None
if selected_path and selected_path.exists():
    st.subheader(f"📄 File: {selected_path.name}")
    render_file(selected_path)
else:
    st.info("Select a file in the sidebar to preview its contents.")

# --- Export metadata tree ---
st.divider()
if st.button("📦 Export Metadata Tree", use_container_width=True):
    tree = export_metadata_tree(ROOT_DIR)
    st.download_button(
        "⬇️ Download Metadata (JSON)",
        data=json.dumps(tree, indent=2),
        file_name="data_directory_tree.json",
        mime="application/json",
        use_container_width=True,
    )
    st.json(tree)