import psycopg as pg
from psycopg.rows import dict_row
from .connection import g_conn_dict as conn

# no undo/redo

_project_open_count: dict[str, int] = {}

_server_databases = ['template0', 'template1', 'postgres', 'project']

def list_project() -> list[str]:
    ps = []
    with pg.connect(conninfo="dbname=postgres host=127.0.0.1", autocommit=True) as conn:
        with conn.cursor(row_factory=dict_row) as cur:
            for p in cur.execute(f"select datname from pg_database where datname <> 'postgres' and datname <> 'template0' and datname <> 'template1' and datname <> 'project'"):
                ps.append(p['datname'])
    return ps

def have_project(name: str) -> bool:
    with pg.connect(conninfo="dbname=postgres host=127.0.0.1", autocommit=True) as conn:
        with conn.cursor() as cur:
            cur.execute(f"select * from pg_database where datname = '{name}'")
            return cur.rowcount > 0

def copy_project(source: str, new: str) -> None:
    with pg.connect(conninfo="dbname=postgres host=127.0.0.1", autocommit=True) as conn:
        with conn.cursor() as cur:
            cur.execute(f"create database {new} with template = {source}")

def create_project(name: str) -> None:
    return copy_project('project', name)

def delete_project(name: str) -> None:
    with pg.connect(conninfo="dbname=postgres host=127.0.0.1", autocommit=True) as conn:
        with conn.cursor() as cur:
            cur.execute(f"drop database {name}")

def clean_project(excluded: list[str] = []) -> None:
    projects = list_project()
    with pg.connect(conninfo="dbname=postgres host=127.0.0.1", autocommit=True) as conn:
        with conn.cursor(row_factory=dict_row) as cur:
            row = cur.execute(f"select current_database()").fetchone()
            if row != None:
                current_db = row['current_database']
                if current_db in projects:
                    projects.remove(current_db)
            for project in projects:
                if project in _server_databases or project in excluded:
                    continue
                cur.execute(f"select pg_terminate_backend(pid) from pg_stat_activity where datname = '{project}'")
                cur.execute(f"drop database {project}")

def open_project(name: str) -> None:
    if name not in _project_open_count:
        conn[name] = pg.connect(conninfo=f"dbname={name} host=127.0.0.1", autocommit=True)
        _project_open_count[name] = 0

    _project_open_count[name] += 1

def is_project_open(name: str) -> bool:
    return name in conn

def get_project_open_count(name: str) -> int:
    if is_project_open(name):
        return _project_open_count[name]
    return 0

def close_project(name: str) -> None:
    if name in _project_open_count:
        _project_open_count[name] -= 1
        if _project_open_count[name] == 0:
            conn[name].close()
            del conn[name]
            del _project_open_count[name]