battery-tracker-app/app.py

from flask import Flask, render_template, redirect, url_for, request, flash, abort
from sqlalchemy import create_engine, func
from sqlalchemy.orm import scoped_session, sessionmaker

from models import Base, Battery, Device


def create_app(config_object="config"):
    app = Flask(__name__)
    app.config.from_object(config_object)

    engine = create_engine(
        app.config["SQLALCHEMY_DATABASE_URI"],
        pool_pre_ping=True,
    )
    Base.metadata.create_all(engine)

    db = scoped_session(sessionmaker(bind=engine))

    @app.teardown_appcontext
    def remove_session(exc=None):
        db.remove()

    # ------------------------------------------------------------------ #
    # Dashboard
    # ------------------------------------------------------------------ #

    @app.route("/")
    def dashboard():
        batteries = db.query(Battery).order_by(Battery.label).all()
        return render_template("dashboard.html", batteries=batteries)

    # ------------------------------------------------------------------ #
    # Battery — add
    # ------------------------------------------------------------------ #

    @app.route("/battery/add", methods=["GET", "POST"])
    def battery_add():
        if request.method == "POST":
            f = request.form
            brand = f.get("brand", "").strip()
            notes = f.get("notes", "").strip() or None
            try:
                count = max(1, min(50, int(f.get("count", 1) or 1)))
            except (ValueError, TypeError):
                count = 1

            if not brand:
                flash("Brand is required.", "error")
                brands = [r[0] for r in db.query(Battery.brand).distinct().order_by(Battery.brand).all()]
                return render_template("battery_add.html",
                                       form_brand="", form_count=1, form_notes=notes or "",
                                       brands=brands), 400

            def _int(key):
                v = f.get(key, "").strip()
                try:
                    return int(v) if v else None
                except ValueError:
                    return None

            size          = f.get("size", "").strip() or None
            chemistry     = f.get("chemistry", "").strip() or None
            capacity_mah  = _int("capacity_mah")
            purchase_date = f.get("purchase_date", "").strip() or None

            existing = db.query(func.count(Battery.id)).filter_by(brand=brand).scalar()
            for i in range(count):
                label = f"{brand} {existing + i + 1:03d}"
                db.add(Battery(label=label, brand=brand, status="available", notes=notes,
                               size=size, chemistry=chemistry,
                               capacity_mah=capacity_mah, purchase_date=purchase_date))
            db.commit()
            flash(f"Added {count} {brand} batter{'y' if count == 1 else 'ies'}.", "success")
            return redirect(url_for("dashboard"))

        brands = [r[0] for r in db.query(Battery.brand).distinct().order_by(Battery.brand).all()]
        return render_template("battery_add.html", form_count=1, brands=brands)

    # ------------------------------------------------------------------ #
    # Battery — detail
    # ------------------------------------------------------------------ #

    @app.route("/battery/<int:battery_id>")
    def battery_detail(battery_id):
        battery = db.get(Battery, battery_id)
        if battery is None:
            abort(404)
        return render_template("battery_detail.html", battery=battery)

    # ------------------------------------------------------------------ #
    # Battery — edit notes
    # ------------------------------------------------------------------ #

    @app.route("/battery/<int:battery_id>/edit-details", methods=["POST"])
    def battery_edit_details(battery_id):
        battery = db.get(Battery, battery_id)
        if battery is None:
            abort(404)
        f = request.form

        def _int(key):
            v = f.get(key, "").strip()
            try:
                return int(v) if v else None
            except ValueError:
                return None

        battery.notes               = f.get("notes", "").strip() or None
        battery.size                = f.get("size", "").strip() or None
        battery.chemistry           = f.get("chemistry", "").strip() or None
        battery.capacity_mah        = _int("capacity_mah")
        battery.tested_capacity_mah = _int("tested_capacity_mah")
        battery.tested_date         = f.get("tested_date", "").strip() or None
        battery.charge_cycles       = _int("charge_cycles")
        battery.purchase_date       = f.get("purchase_date", "").strip() or None

        db.commit()
        flash("Details updated.", "success")
        return redirect(url_for("battery_detail", battery_id=battery_id))

    # ------------------------------------------------------------------ #
    # Battery — assign
    # ------------------------------------------------------------------ #

    @app.route("/battery/<int:battery_id>/assign", methods=["GET", "POST"])
    def battery_assign(battery_id):
        battery = db.get(Battery, battery_id)
        if battery is None:
            abort(404)

        if battery.is_retired():
            flash("Cannot assign a retired battery.", "error")
            return redirect(url_for("battery_detail", battery_id=battery_id))

        devices = db.query(Device).order_by(Device.name).all()

        if request.method == "POST":
            device_id = request.form.get("device_id", type=int)
            device = db.get(Device, device_id)
            if device is None:
                flash("Device not found.", "error")
                return render_template("assign.html", battery=battery, devices=devices)

            if device.installed_count() >= device.battery_slots:
                flash(
                    f"{device.name} is already full "
                    f"({device.battery_slots}/{device.battery_slots} slots used).",
                    "error",
                )
                return render_template("assign.html", battery=battery, devices=devices)

            # Warn on brand mix (non-blocking)
            existing_brands = device.installed_brands()
            if existing_brands and battery.brand not in existing_brands:
                flash(
                    f"Warning: {device.name} already has batteries from "
                    f"{', '.join(existing_brands)}. Mixing brands is not recommended.",
                    "warning",
                )

            # Unassign from previous device if needed
            if battery.device_id is not None:
                battery.device_id = None

            battery.status = "installed"
            battery.device_id = device.id
            db.commit()
            flash(f"{battery.label} assigned to {device.name}.", "success")
            return redirect(url_for("dashboard"))

        return render_template("assign.html", battery=battery, devices=devices)

    # ------------------------------------------------------------------ #
    # Battery — unassign
    # ------------------------------------------------------------------ #

    @app.route("/battery/<int:battery_id>/unassign", methods=["POST"])
    def battery_unassign(battery_id):
        battery = db.get(Battery, battery_id)
        if battery is None:
            abort(404)
        battery.status = "available"
        battery.device_id = None
        db.commit()
        flash(f"{battery.label} unassigned and marked available.", "success")
        return redirect(url_for("dashboard"))

    # ------------------------------------------------------------------ #
    # Battery — retire
    # ------------------------------------------------------------------ #

    @app.route("/battery/<int:battery_id>/retire", methods=["POST"])
    def battery_retire(battery_id):
        battery = db.get(Battery, battery_id)
        if battery is None:
            abort(404)
        if battery.is_retired():
            flash(f"{battery.label} is already retired.", "error")
            return redirect(url_for("battery_detail", battery_id=battery_id))
        battery.status = "retired"
        battery.device_id = None
        db.commit()
        flash(f"{battery.label} has been retired.", "success")
        return redirect(url_for("dashboard"))

    # ------------------------------------------------------------------ #
    # Battery — delete
    # ------------------------------------------------------------------ #

    @app.route("/battery/<int:battery_id>/delete", methods=["GET", "POST"])
    def battery_delete(battery_id):
        battery = db.get(Battery, battery_id)
        if battery is None:
            abort(404)
        if request.method == "POST":
            label = battery.label
            db.delete(battery)
            db.commit()
            flash(f"Battery {label} permanently deleted.", "success")
            return redirect(url_for("dashboard"))
        return render_template("battery_delete.html", battery=battery)

    # ------------------------------------------------------------------ #
    # Battery — bulk action
    # ------------------------------------------------------------------ #

    @app.route("/battery/bulk-action", methods=["POST"])
    def battery_bulk_action():
        ids = request.form.getlist("battery_ids", type=int)
        if not ids:
            flash("No batteries selected.", "error")
            return redirect(url_for("dashboard"))

        batteries = db.query(Battery).filter(Battery.id.in_(ids)).all()
        action = request.form.get("action")
        n = len(batteries)

        if action == "retire":
            for b in batteries:
                b.status = "retired"
                b.device_id = None
            db.commit()
            flash(f"Retired {n} batter{'y' if n == 1 else 'ies'}.", "success")
        elif action == "delete":
            for b in batteries:
                db.delete(b)
            db.commit()
            flash(f"Deleted {n} batter{'y' if n == 1 else 'ies'}.", "success")
        elif action == "unassign":
            count = sum(1 for b in batteries if b.is_installed())
            for b in batteries:
                if b.is_installed():
                    b.status = "available"
                    b.device_id = None
            db.commit()
            flash(f"Unassigned {count} batter{'y' if count == 1 else 'ies'}.", "success")
        elif action == "set_brand":
            new_brand = request.form.get("new_brand", "").strip()
            if not new_brand:
                flash("Brand name is required.", "error")
                return redirect(url_for("dashboard"))
            for b in batteries:
                b.brand = new_brand
            db.commit()
            flash(f"Updated brand to '{new_brand}' for {n} batter{'y' if n == 1 else 'ies'}.", "success")
        else:
            flash("Unknown action.", "error")

        return redirect(url_for("dashboard"))

    # ------------------------------------------------------------------ #
    # Devices — list
    # ------------------------------------------------------------------ #

    @app.route("/device/")
    def device_list():
        devices = db.query(Device).order_by(Device.name).all()
        return render_template("device_list.html", devices=devices)

    # ------------------------------------------------------------------ #
    # Devices — add
    # ------------------------------------------------------------------ #

    @app.route("/device/add", methods=["GET", "POST"])
    def device_add():
        if request.method == "POST":
            name = request.form.get("name", "").strip()
            slots_raw = request.form.get("battery_slots", "1").strip()
            notes = request.form.get("notes", "").strip() or None

            if not name:
                flash("Device name is required.", "error")
                return render_template("device_add.html"), 400

            try:
                slots = int(slots_raw)
                if slots < 1:
                    raise ValueError
            except ValueError:
                flash("Battery slots must be a positive integer.", "error")
                return render_template("device_add.html",
                                       form_name=name, form_notes=notes or ""), 400

            if db.query(Device).filter_by(name=name).first():
                flash(f"A device named '{name}' already exists.", "error")
                return render_template("device_add.html",
                                       form_name=name, form_slots=slots,
                                       form_notes=notes or ""), 400

            device = Device(name=name, battery_slots=slots, notes=notes)
            db.add(device)
            db.commit()
            flash(f"Device '{name}' added.", "success")
            return redirect(url_for("device_list"))

        return render_template("device_add.html")

    # ------------------------------------------------------------------ #
    # Devices — detail
    # ------------------------------------------------------------------ #

    @app.route("/device/<int:device_id>")
    def device_detail(device_id):
        device = db.get(Device, device_id)
        if device is None:
            abort(404)
        brands = [r[0] for r in db.query(Battery.brand).distinct().order_by(Battery.brand).all()]
        return render_template("device_detail.html", device=device, brands=brands)

    # ------------------------------------------------------------------ #
    # Devices — install batteries
    # ------------------------------------------------------------------ #

    @app.route("/device/<int:device_id>/install", methods=["POST"])
    def device_install(device_id):
        device = db.get(Device, device_id)
        if device is None:
            abort(404)

        brands = request.form.getlist("brand[]")
        qtys_raw = request.form.getlist("qty[]")

        pairs = []
        for brand, qty_raw in zip(brands, qtys_raw):
            brand = brand.strip()
            try:
                qty = int(qty_raw)
            except (ValueError, TypeError):
                qty = 0
            if brand and qty > 0:
                pairs.append((brand, qty))

        if not pairs:
            flash("No batteries specified.", "error")
            return redirect(url_for("device_detail", device_id=device_id))

        free_slots = device.battery_slots - device.installed_count()
        total_requested = sum(qty for _, qty in pairs)
        if total_requested > free_slots:
            flash(
                f"Only {free_slots} slot(s) free, but {total_requested} requested.",
                "error",
            )
            return redirect(url_for("device_detail", device_id=device_id))

        # Validate availability before writing anything
        for brand, qty in pairs:
            available_count = (
                db.query(func.count(Battery.id))
                .filter_by(brand=brand, status="available")
                .scalar()
            )
            if available_count < qty:
                flash(
                    f"Need {qty} {brand}, but only {available_count} available.",
                    "error",
                )
                return redirect(url_for("device_detail", device_id=device_id))

        # All checks passed — perform installs
        total_installed = 0
        for brand, qty in pairs:
            batch = (
                db.query(Battery)
                .filter_by(brand=brand, status="available")
                .order_by(Battery.id)
                .limit(qty)
                .all()
            )
            for b in batch:
                b.status = "installed"
                b.device_id = device.id
                total_installed += 1

        db.commit()
        flash(
            f"Installed {total_installed} batter{'y' if total_installed == 1 else 'ies'}"
            f" into {device.name}.",
            "success",
        )
        return redirect(url_for("device_detail", device_id=device_id))

    # ------------------------------------------------------------------ #
    # Devices — delete
    # ------------------------------------------------------------------ #

    @app.route("/device/<int:device_id>/delete", methods=["POST"])
    def device_delete(device_id):
        device = db.get(Device, device_id)
        if device is None:
            abort(404)
        for battery in device.batteries:
            battery.status = "available"
            battery.device_id = None
        name = device.name
        db.delete(device)
        db.commit()
        flash(f"Device '{name}' deleted. All batteries marked available.", "success")
        return redirect(url_for("device_list"))

    return app


app = create_app()

if __name__ == "__main__":
    app.run(debug=True)