import logging
import sqlite3
from collections import namedtuple
from contextlib import contextmanager
from typing import Generator

from gistillery.config import get_config

logger = logging.getLogger(__name__)
logger.setLevel(logging.DEBUG)


schema_entries = """
CREATE TABLE entries
(
    id TEXT PRIMARY KEY,
    author TEXT NOT NULL,
    source TEXT NOT NULL,
    source_snippet TEXT NOT NULL,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
)
"""

# create schema for 'summary' table, id is a uuid4
schema_summary = """
CREATE TABLE summaries
(
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    entry_id TEXT NOT NULL,
    summary TEXT NOT NULL,
    summarizer_name TEXT NOT NULL,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    FOREIGN KEY(entry_id) REFERENCES entries(id)
)
"""

schema_tag = """
CREATE TABLE tags
(
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    entry_id TEXT NOT NULL,
    tag TEXT NOT NULL,
    tagger_name TEXT NOT NULL,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    FOREIGN KEY(entry_id) REFERENCES entries(id)
)
"""

schema_job = """
CREATE TABLE jobs
(
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    entry_id TEXT NOT NULL,
    status TEXT NOT NULL DEFAULT 'pending',
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    last_updated TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    FOREIGN KEY(entry_id) REFERENCES entries(id)
)
"""

# store the processed inputs
schema_inputs = """
CREATE TABLE inputs
(
    id INTEGER PRIMARY KEY AUTOINCREMENT,
    entry_id TEXT NOT NULL,
    input TEXT NOT NULL,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    FOREIGN KEY(entry_id) REFERENCES entries(id)
)
"""

TABLES = {
    'entries': schema_entries,
    'summaries': schema_summary,
    'tags': schema_tag,
    'jobs': schema_job,
    'inputs': schema_inputs,
}
TABLES_CREATED = False


# https://docs.python.org/3/library/sqlite3.html#how-to-create-and-use-row-factories
def namedtuple_factory(cursor, row):  # type: ignore
    fields = [column[0] for column in cursor.description]
    cls = namedtuple("Row", fields)  # type: ignore
    return cls._make(row)


def get_db_connection() -> sqlite3.Connection:
    global TABLES_CREATED

    # sqlite cannot deal with concurrent access, so we set a big timeout
    conn = sqlite3.connect(get_config().db_file_name, timeout=30)
    conn.row_factory = namedtuple_factory
    if TABLES_CREATED:
        return conn

    cursor = conn.cursor()

    # create tables if needed
    for table_name, schema in TABLES.items():
        cursor.execute(
            "SELECT name FROM sqlite_master WHERE type='table' AND name=?",
            (table_name,),
        )
        table_exists = cursor.fetchone() is not None
        if not table_exists:
            logger.info(f"'{table_name}' table does not exist, creating it now...")
            cursor.execute(schema)
            conn.commit()
            logger.info("done")

    TABLES_CREATED = True
    return conn


@contextmanager
def get_db_cursor() -> Generator[sqlite3.Cursor, None, None]:
    conn = get_db_connection()
    cursor = conn.cursor()
    try:
        yield cursor
    finally:
        conn.commit()
        cursor.close()
        conn.close()