fieldwitness/frontends/web/app.py

"""
SooSeF Web Frontend

Flask application factory that unifies Stegasoo (steganography) and Verisoo
(provenance attestation) into a single web UI with fieldkit security features.

Built on Stegasoo's production-grade web UI patterns:
- Subprocess isolation for crash-safe stegasoo operations
- Async jobs with progress polling for large images
- Context processors for global template variables
- File-based temp storage with auto-expiry

BLUEPRINT STRUCTURE
===================

    /                   → index (dashboard)
    /login, /logout     → auth (adapted from stegasoo)
    /setup              → first-run wizard

    /encode, /decode, /generate, /tools  → stego blueprint
    /attest, /verify                     → attest blueprint
    /fieldkit/*                          → fieldkit blueprint
    /keys/*                              → keys blueprint
    /admin/*                             → admin blueprint
"""

import os
import secrets
import sys
from pathlib import Path

from flask import Flask, redirect, render_template, url_for

import soosef
from soosef.config import SoosefConfig
from soosef.paths import AUTH_DB, INSTANCE_DIR, SECRET_KEY_FILE, TEMP_DIR, ensure_dirs

# Suppress numpy/scipy warnings in subprocesses
os.environ["NUMPY_MADVISE_HUGEPAGE"] = "0"
os.environ["OMP_NUM_THREADS"] = "1"

# Maximum upload size (50 MB default)
MAX_FILE_SIZE = 50 * 1024 * 1024


def create_app(config: SoosefConfig | None = None) -> Flask:
    """Application factory."""
    config = config or SoosefConfig.load()
    ensure_dirs()

    app = Flask(
        __name__,
        instance_path=str(INSTANCE_DIR),
        template_folder=str(Path(__file__).parent / "templates"),
        static_folder=str(Path(__file__).parent / "static"),
    )

    app.config["MAX_CONTENT_LENGTH"] = config.max_upload_mb * 1024 * 1024
    app.config["AUTH_ENABLED"] = config.auth_enabled
    app.config["HTTPS_ENABLED"] = config.https_enabled
    app.config["SOOSEF_CONFIG"] = config

    # Persist secret key so sessions survive restarts
    _load_secret_key(app)

    # ── Register blueprints ───────────────────────────────────────

    from frontends.web.blueprints.stego import bp as stego_bp
    from frontends.web.blueprints.attest import bp as attest_bp
    from frontends.web.blueprints.fieldkit import bp as fieldkit_bp
    from frontends.web.blueprints.keys import bp as keys_bp
    from frontends.web.blueprints.admin import bp as admin_bp

    app.register_blueprint(stego_bp)
    app.register_blueprint(attest_bp)
    app.register_blueprint(fieldkit_bp)
    app.register_blueprint(keys_bp)
    app.register_blueprint(admin_bp)

    # ── Context processor (injected into ALL templates) ───────────

    @app.context_processor
    def inject_globals():
        from soosef.keystore import KeystoreManager

        ks = KeystoreManager()
        ks_status = ks.status()

        # Check fieldkit alert level
        fieldkit_status = "ok"
        if config.deadman_enabled:
            from soosef.fieldkit.deadman import DeadmanSwitch

            dm = DeadmanSwitch()
            if dm.should_fire():
                fieldkit_status = "alarm"
            elif dm.is_overdue():
                fieldkit_status = "warn"

        # Check stegasoo capabilities
        try:
            from stegasoo import has_dct_support, HAS_AUDIO_SUPPORT

            has_dct = has_dct_support()
            has_audio = HAS_AUDIO_SUPPORT
        except ImportError:
            has_dct = False
            has_audio = False

        # Check verisoo availability
        try:
            import verisoo  # noqa: F401

            has_verisoo = True
        except ImportError:
            has_verisoo = False

        return {
            "version": soosef.__version__,
            "has_dct": has_dct,
            "has_audio": has_audio,
            "has_verisoo": has_verisoo,
            "has_fieldkit": config.killswitch_enabled or config.deadman_enabled,
            "fieldkit_status": fieldkit_status,
            "channel_configured": ks_status.has_channel_key,
            "channel_fingerprint": ks_status.channel_fingerprint or "",
            "identity_configured": ks_status.has_identity,
            "identity_fingerprint": ks_status.identity_fingerprint or "",
            "auth_enabled": app.config["AUTH_ENABLED"],
            "is_authenticated": _is_authenticated(),
            "is_admin": _is_admin(),
            "username": _get_username(),
        }

    # ── Root routes ───────────────────────────────────────────────

    @app.route("/")
    def index():
        return render_template("index.html")

    return app


def _load_secret_key(app: Flask) -> None:
    """Load or generate persistent secret key for Flask sessions."""
    SECRET_KEY_FILE.parent.mkdir(parents=True, exist_ok=True)
    if SECRET_KEY_FILE.exists():
        app.secret_key = SECRET_KEY_FILE.read_bytes()
    else:
        key = secrets.token_bytes(32)
        SECRET_KEY_FILE.write_bytes(key)
        SECRET_KEY_FILE.chmod(0o600)
        app.secret_key = key


def _is_authenticated() -> bool:
    """Check if current request has an authenticated session."""
    # TODO: Wire up auth.py from stegasoo
    return True


def _is_admin() -> bool:
    """Check if current user is an admin."""
    # TODO: Wire up auth.py from stegasoo
    return True


def _get_username() -> str:
    """Get current user's username."""
    # TODO: Wire up auth.py from stegasoo
    return "admin"