from datetime import date
from fastapi import HTTPException
from database import connect
from models import CATEGORIES, MONTHS, cents, valid_date, percent


def assets():
    with connect() as db:
        return db.execute('SELECT * FROM assets ORDER BY name COLLATE NOCASE').fetchall()


def get_entry(entry_id):
    if not 1 <= entry_id <= 9223372036854775807:
        raise HTTPException(404, 'Zahlung nicht gefunden.')
    with connect() as db:
        row = db.execute('SELECT * FROM income_entries WHERE id = ?', (entry_id,)).fetchone()
    if row is None:
        raise HTTPException(404, 'Zahlung nicht gefunden.')
    return dict(row)


def save_entry(data, entry_id=None):
    if entry_id is not None and not 1 <= entry_id <= 9223372036854775807:
        raise HTTPException(404, 'Zahlung nicht gefunden.')
    day = valid_date(data.get('date', ''))
    amount = cents(data.get('amount', ''))
    category = data.get('category', '')
    if category not in CATEGORIES:
        raise ValueError('Bitte eine gültige Kategorie auswählen.')
    try:
        asset_id = int(data.get('asset_id', ''))
        if not 1 <= asset_id <= 9223372036854775807:
            raise ValueError
    except (TypeError, ValueError):
        raise ValueError('Bitte eine Position auswählen.') from None
    note = data.get('note', '').strip()
    if len(note) > 2000:
        raise ValueError('Notiz darf maximal 2000 Zeichen enthalten.')
    expected, received = int(data.get('expected') == '1'), int(data.get('received') == '1')
    with connect() as db:
        db.execute('BEGIN IMMEDIATE')
        existing = db.execute('SELECT * FROM income_entries WHERE id = ?', (entry_id,)).fetchone() if entry_id else None
        if entry_id and existing is None:
            raise HTTPException(404, 'Zahlung nicht gefunden.')
        asset = db.execute('SELECT * FROM assets WHERE id = ?', (asset_id,)).fetchone()
        if asset is None or (not asset['active'] and (existing is None or existing['asset_id'] != asset_id)):
            raise ValueError('Diese Position ist nicht mehr verfügbar.')
        values = (day, asset_id, category, amount, note or None, expected, received)
        if entry_id:
            db.execute("UPDATE income_entries SET date=?, asset_id=?, category=?, amount=?, note=?, expected=?, received=?, updated_at=strftime('%Y-%m-%dT%H:%M:%fZ','now') WHERE id=?", (*values, entry_id))
        else:
            entry_id = db.execute('INSERT INTO income_entries (date,asset_id,category,amount,note,expected,received) VALUES (?,?,?,?,?,?,?)', values).lastrowid
    return entry_id


def list_entries(year=None, month=None, asset_id=None, category=None, limit=None, offset=0):
    # SQL fragments are constants. All filter values remain bound parameters.
    clauses, args = [], []
    for sql, value in [("substr(i.date,1,4) = ?", str(year) if year else None),
                       ("substr(i.date,6,2) = ?", f'{month:02}' if month else None),
                       ('i.asset_id = ?', asset_id), ('i.category = ?', category)]:
        if value is not None:
            clauses.append(sql)
            args.append(value)
    query = 'SELECT i.*, a.name FROM income_entries i JOIN assets a ON a.id=i.asset_id'
    if clauses:
        query += ' WHERE ' + ' AND '.join(clauses)
    query += ' ORDER BY i.date DESC, i.id DESC'
    if limit is not None:
        query += ' LIMIT ? OFFSET ?'
        args.extend([limit, offset])
    with connect() as db:
        return db.execute(query, args).fetchall()


def available_years():
    with connect() as db:
        return [int(row[0]) for row in db.execute('SELECT DISTINCT substr(date,1,4) FROM income_entries ORDER BY 1')]


def dashboard(today=None):
    today = today or date.today()
    with connect() as db:
        grouped = db.execute("SELECT substr(date,1,4) year, substr(date,6,2) month, SUM(amount) amount, COUNT(*) count FROM income_entries WHERE received=1 GROUP BY year, month").fetchall()
        shares = [dict(r) for r in db.execute('SELECT a.name, SUM(i.amount) amount FROM income_entries i JOIN assets a ON a.id=i.asset_id WHERE received=1 GROUP BY a.id ORDER BY amount DESC')]
        kinds = {r['category']: r['amount'] for r in db.execute('SELECT category, SUM(amount) amount FROM income_entries WHERE received=1 GROUP BY category')}
        pending = db.execute('SELECT COUNT(*) count, COALESCE(SUM(amount),0) amount FROM income_entries WHERE expected=1 AND received=0').fetchone()
    years_found = available_years()
    years = list(range(min(years_found + [today.year]), max(years_found + [today.year + 1]) + 1))
    monthly = {year: [0] * 12 for year in years}
    count = 0
    for row in grouped:
        year = int(row['year'])
        monthly[year][int(row['month']) - 1] = row['amount']
        if year == today.year:
            count += row['count']
    totals = {year: sum(values) for year, values in monthly.items()}
    current_month = monthly[today.year][today.month - 1]
    prior_month = monthly.get(today.year - 1, [0] * 12)[today.month - 1]
    prior_year = totals.get(today.year - 1, 0)
    return dict(years=years, monthly=monthly, totals=totals, month=current_month, prior_month=prior_month,
                month_change=percent(current_month, prior_month), year=totals[today.year], prior_year=prior_year,
                year_change=percent(totals[today.year], prior_year), all_time=sum(totals.values()), count=count,
                pending=dict(pending), today=today, shares=shares,
                chart={'months': MONTHS, 'years': [{'label': str(y), 'data': monthly[y]} for y in years],
                       'shares': shares, 'kinds': [{'name': 'Dividenden / Ausschüttungen', 'amount': kinds.get('dividend',0)+kinds.get('distribution',0)},
                                                  {'name': 'Zinsen', 'amount': kinds.get('interest',0)}, {'name': 'Sonstiges', 'amount': kinds.get('other',0)}]})