import base64
import email.message
import os
import smtplib

import markdown
import psycopg

from flask import Flask, render_template, g, url_for, session, request
from markupsafe import Markup

import config

app = Flask(__name__)
app.config.from_object(config)

#-----------------------------------------------------------------------

# HTTP endpoints

@app.get("/")
def index():
    return show_posts("")

@app.get("/<path:p>")
def show_posts(p):
    roles = get_roles()
    app.logger.info(f"{p}")
    tags = p.split("/")
    csr = get_cursor()
    csr.execute("select * from tag where lower(name) = any(%s)", (tags,))
    tag_ids = [r.id for r in csr]
    # XXX - Check that tag_ids has the same length as tags.
    # Otherwise
    # - return 404?
    # - redirect?
    q = "select distinct p.* from post p"
    for tag_id in tag_ids:
        # we got tag_id from the database so we know it's an int
        q += f" join tag_post t{tag_id} on p.id = t{tag_id}.post and t{tag_id}.tag = {tag_id}"
    # and the user_id is an int, too
    q += f" join acl on p.id = acl.post and acl.role = any(%s)"
    q += " order by p.ts desc"
    csr.execute(q, (roles,))
    posts = csr.fetchall()
    # XXX find all tags for each post
    post_ids = [p.id for p in posts]
    csr.execute(
            "select * from tag_post tp join tag t on tp.tag = t.id where post = any(%s) order by name",
            (post_ids,))
    tags_by_id = {}
    tags_by_post = {}
    for r in csr:
        if r.id not in tags_by_id:
            selected = r.id in tag_ids
            if selected:
                # XXX - should really use id
                new_tags = [t for t in tags if t != r.name.lower()]
            else:
                new_tags = tags + [r.name.lower()]
            link = url_for("show_posts", p="/".join(new_tags))
            tags_by_id[r.id] = { "id": r.id, "name": r.name, "selected": selected, "link": link }
        tags_by_post.setdefault(r.post, []).append(tags_by_id[r.id])
    tags = tags_by_id.values()



    return render_template(
                "posts.html",
                posts=posts, tags=tags, tags_by_post=tags_by_post,
                )


# XXX - do we need a prefix for paths?
# Or use a separate domain for the api (no)
# Or use an impossible prefix for the api (what would that be?)
#@get("/api")

#@get("/@/add_post")
#@post("/@/add_post")
    # also json

#@get("/@/tag/<tag_name_or_id>")
    # plus one or more posts for operations, like editing implies, bulk
    # updates, etc.

@app.get("/@/login")
def login_form():
    # could duplicate as registration
    return render_template("login_form.html")

@app.post("/@/login")
def login_step1():
    csr = get_cursor()
    email = request.form["email"].strip()
    csr.execute("select * from role where email = %s", (email,))
    r = csr.fetchone()
    if not r:
        csr.execute("insert into role(email) values(%s) returning *", (email,))
        r = csr.fetchone()
    user_id = r.id
    key = base64.urlsafe_b64encode(os.urandom(15)).decode('us-ascii')
    csr.execute("insert into confirm_token(role, token) values(%s, %s) returning *", (user_id, key,))
    r = csr.fetchone()
    csr.connection.commit()
    send_mail(email, request.root_url + url_for("login_confirm", key=key))
    return render_template("mail_sent.html")

@app.get("/@/confirm")
def login_confirm():
    # XXX - Check that key isn't expired
    return render_template("login_confirm.html")

@app.post("/@/confirm")
def do_confirm():
    csr = get_cursor()
    csr.execute("delete from confirm_token where expires <= now()")
    csr.execute(
            """
            select id, name from confirm_token t join role r on t.role = r.id
            where token = %s
            """,
            (request.form["key"],))
    r = csr.fetchone()
    if r:
        csr.execute(
                """
                update role
                set first_confirmed = coalesce(first_confirmed, now()),
                    last_confirmed = now()
                where id = %s
                """,
                (r.id,))

        session["user_id"] = r.id
        session["user_name"] = r.name
        return render_template("welcome.html")
    else:
        return render_template("no_token.html")

@app.route("/@/logout", methods=["GET", "POST"])
def logout():
    del session["user_id"]
    del session["user_name"]
    return redirect("/", code=303)

#@get("/~user")
    # maybe too oldskool? use @user?
#@get("/~user/token")

#-----------------------------------------------------------------------

# Content generation

@app.template_filter("markdown")
def markdown_to_html(m):
    return Markup(markdown.markdown(m))

def send_mail(email_address, confirmation_url):
    msg = email.message.EmailMessage()
    msg["From"] ="noreply@hjp.at"
    msg["To"] = email_address
    msg["Subject"] = "Zettel confirmation"
    body = confirmation_url # Really minimalistic
    msg.set_content(body)
    mta = smtplib.SMTP(host="localhost")
    mta.send_message(msg)

#-----------------------------------------------------------------------

# Plumbing

def get_roles():
    user_id = session.get("user_id")
    csr = get_cursor()
    if not user_id:
        csr.execute("select * from role where name = %s", ("public",))
        r = csr.fetchone()
        user_id = session["user_id"] = r.id
        session["user_name"] = r.name
    assert type(user_id) == int
    roles = [user_id]
    csr.execute(
            """
            with recursive r as (
                select group_role from role_member where member_role = %s
                union
                select role_member.group_role from role_member join r on role_member.member_role = r.group_role
            )
            select * from r
            """,
            (user_id,))
    for r in csr:
        roles.append(r.group_role)
    return roles

def get_cursor():
    db = get_db()
    csr = db.cursor(row_factory=psycopg.rows.namedtuple_row)
    return csr

def get_db():
    if "db" not in g:
        g.db = psycopg.connect(dbname=config.dbname, user=config.dbuser)
    return g.db

@app.teardown_appcontext
def teardown_db(exception):
    app.logger.debug("in teardown_db: exception = %s", exception)
    db = g.pop('db', None)
    if db is not None:
        if not exception:
            try:
                db.commit()
            except:
                pass
        db.rollback()
        db.close()