import os

from cs50 import SQL
from flask import Flask, flash, redirect, render_template, request, session
from flask_session import Session
from tempfile import mkdtemp
from werkzeug.exceptions import default_exceptions, HTTPException, InternalServerError
from werkzeug.security import check_password_hash, generate_password_hash

from helpers import apology, deal_finder, login_required, passw_requirements, usd

# Configure application
app = Flask(__name__)

# Ensure templates are auto-reloaded
app.config["TEMPLATES_AUTO_RELOAD"] = True

# Ensure responses aren't cached, allows smoother implementation of development-changes
@app.after_request
def after_request(response):
    response.headers["Cache-Control"] = "no-cache, no-store, must-revalidate"
    response.headers["Expires"] = 0
    response.headers["Pragma"] = "no-cache"
    return response

# Custom filter
app.jinja_env.filters["usd"] = usd

# Configure session to use filesystem (instead of signed cookies, to avoid multiple cookies in one browser)
app.config["SESSION_FILE_DIR"] = mkdtemp()
app.config["SESSION_PERMANENT"] = False
app.config["SESSION_TYPE"] = "filesystem"
Session(app)

# Configure the SQLite database
db = SQL("sqlite:///spending.db")


@app.route("/")
def home():
    """Home page with different versions for visiting guests & logged-in users """

    # When a non-registered guest visits the website:
    if not session:
        return render_template("welcome.html")

    # For a logged-in user:
    else:
        user_id = session["user_id"]

        # Getting username & budget
        user_info = db.execute("SELECT * FROM users WHERE id = ?", user_id)
        username = user_info[0]["username"]
        cash = user_info[0]["cash"]

        # Getting total amount of money spent in each category
        amounts = []
        categories = ['%Rent', '%Maintenance', '%Food', '%Family', '%Pets', '%Clothes', '%Hobbies', '%Investing', '%Other']

        for element in categories:
            result = db.execute("SELECT SUM(amount) FROM expenses WHERE user_id = ? AND category LIKE ?", user_id, element)[0]["SUM(amount)"]
            if result == None:
                result = 0
            amounts.append(result)

        return render_template("home.html",  name=username, cash=cash, rent=amounts[0], maintain=amounts[1], food=amounts[2], family=amounts[3],
                                pets=amounts[4], clothes=amounts[5], hobbies=amounts[6], invest=amounts[7], other=amounts[8])


@app.route("/account", methods=["GET", "POST"])
@login_required
def account():
    """ View user data & replace passsword """

    user_id = session["user_id"]
    user_info = db.execute("SELECT * FROM users WHERE id = ?", user_id)
    username = user_info[0]["username"]
    cash = user_info[0]["cash"]

    if request.method == "GET":
        return render_template("account.html", name=username, budget=cash)

    else:
        # allowing the user to set a new password for their account
        pw_new = request.form.get("pw_new")
        if not check_password_hash(user_info[0]["hash"], request.form.get("pw_old")):
            return apology("Your old password was not correct", 400)
        elif pw_new != request.form.get("confirmation"):
            return apology("New Password and Confirm New Password did not match", 400)
        elif passw_requirements(pw_new) != "valid":
            return apology("Password must be between 6 and 25 characters long and contain at least one number and one letter", 400)

        # replace password in the db if all requirements were met
        db.execute("UPDATE users SET hash = ? WHERE username = ?", generate_password_hash(pw_new), username)
        flash("You successfully changed your password!")
        return render_template("/account.html", name=username, budget=cash)


@app.route("/bargain", methods=["GET", "POST"])
@login_required
def bargain():
    """Search for & display cheapest deals for a user-specified item """

    # display search form
    if request.method == "GET":
        return render_template("bargain.html")
    # display results collected & sorted by web scraping helper function
    else:
        item = request.form.get("product-search")
        deals = deal_finder(item)

        return render_template("bargain.html", deals=deals)


@app.route("/budget", methods=["GET", "POST"])
@login_required
def budget():
    """ View & set budget """

    user_id = session["user_id"]
    budget = db.execute("SELECT cash FROM users WHERE id = ?", user_id)[0]["cash"]

    # view current budget
    if request.method == "GET":
        return render_template("budget.html", budget=budget)

    # update budget
    else:
        added_budget = request.form.get("add_budget")
        new_budget = float(budget) + float(added_budget)
        db.execute("UPDATE users SET cash = ? WHERE id = ?", new_budget, user_id)

        flash("Budget updated!")
        return render_template("budget.html", budget=new_budget)


@app.route("/history")
@login_required
def history():
    """ Show record of all previous expenses """

    user_id = session["user_id"]
    record = db.execute("SELECT * FROM expenses WHERE user_id = ? ORDER BY date", user_id)
    return render_template("history.html", record=record)


@app.route("/login", methods=["GET", "POST"])
def login():
    """Log user in"""

    # Forget any user_id
    session.clear()

    # User reached the route via GET:
    if request.method == "GET":
        return render_template("login.html")

    # User submitted via POST to log in:
    else:
         # Ensure username was submitted
        if not request.form.get("username"):
            return apology("must provide username", 403)

        # Ensure password was submitted
        elif not request.form.get("password"):
            return apology("must provide password", 403)

        # Query database for username
        rows = db.execute("SELECT * FROM users WHERE username = ?", request.form.get("username"))

        # Ensure username exists and password is correct
        if len(rows) != 1 or not check_password_hash(rows[0]["hash"], request.form.get("password")):
            return apology("invalid username and/or password", 403)

        # Remember which user has logged in
        session["user_id"] = rows[0]["id"]

        # Redirect user to home page
        return redirect("/")


@app.route("/logout")
def logout():
    """Log user out"""

    # Forget any user_id
    session.clear()

    # Redirect user to login form
    return redirect("/")


@app.route("/register", methods=["GET", "POST"])
def register():
    """ Register a new user account """

    # If the user visits this route, display the form to sign up for a new account
    if request.method == "GET":
        return render_template("register.html")

    # If the user submits their registration with POST
    else:
        # Get the user's name & password from the form
        reg_name = request.form.get("username")
        reg_passw = request.form.get("password")

        # Checking if the user failed to provide a username & password, if the name is already taken or if the confirmed password was different
        if not reg_name:
            return apology("Please enter a username", 400)
        elif len(db.execute("SELECT * FROM users WHERE username = ?", reg_name)) != 0:
            return apology("Username is already taken", 400)
        elif not reg_passw:
            return apology("Please choose a unique password", 400)
        elif reg_passw != request.form.get("confirmation"):
            return apology("Password and Confirm Password did not match", 400)
        # Special check with a helper function for password safety
        elif passw_requirements(reg_passw) != "valid":
            return apology("Password must be between 6 and 25 characters long and contain at least one number and one letter", 400)

        # Otherwise register the new user into the database (with a hashed password for extra security) and redirect them to the main page
        db.execute("INSERT INTO users (username, hash) VALUES (?, ?)", reg_name, generate_password_hash(reg_passw))
        return redirect("/login")


@app.route("/tracker", methods=["POST", "GET"])
@login_required
def tracker():
    """ Add new expenses """

    # Display form to add a new expense
    if request.method == "GET":
        return render_template("tracker.html")
    # When submitting a new expense:
    else:
        user_id = session["user_id"]
        budget = db.execute("SELECT cash FROM users WHERE id = ?", user_id)[0]["cash"]

        # ternary condition if the user does not give an optional comment on the expense
        comment = "Unspecified" if not request.form.get("comment") else request.form.get("comment")
        category, amount, date = request.form.get("category"), request.form.get("amount", type=float), request.form.get("date")

        # subtract expense from budget
        updated_budget = float(budget) - amount
        db.execute("UPDATE users SET cash = ? WHERE id = ?", updated_budget, user_id)

        # update table "expenses" in database for use in history.html
        db.execute("INSERT INTO expenses (user_id, comment, category, amount, date) VALUES (?, ?, ?, ?, ?)",
                    user_id, comment, category, amount, date)
        return redirect("/")


# Handle errors
def errorhandler(e):
    if not isinstance(e, HTTPException):
        e = InternalServerError()
    return apology(e.name, e.code)


# Listen for errors
for code in default_exceptions:
    app.errorhandler(code)(errorhandler)