"""Per-user product analytics stored in a separate SQLite database."""
from __future__ import annotations

from contextlib import closing
import datetime as dt
import os
import sqlite3
from pathlib import Path

DEFAULT_DB_PATH = "/app/data/analytics.sqlite3"


def connect(db_path: str | None = None) -> sqlite3.Connection:
    path = Path(db_path or os.getenv("ANALYTICS_DB_PATH", DEFAULT_DB_PATH))
    path.parent.mkdir(parents=True, exist_ok=True)
    connection = sqlite3.connect(path, timeout=10)
    connection.row_factory = sqlite3.Row
    connection.execute("PRAGMA busy_timeout = 10000")
    connection.execute("PRAGMA journal_mode = WAL")
    return connection


def init_db(db_path: str | None = None) -> None:
    with closing(connect(db_path)) as connection, connection:
        connection.execute(
            """
            CREATE TABLE IF NOT EXISTS events (
                id INTEGER PRIMARY KEY AUTOINCREMENT,
                telegram_user_id INTEGER NOT NULL,
                mode TEXT NOT NULL,
                event_type TEXT NOT NULL,
                message_type TEXT,
                created_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP
            )
            """
        )
        connection.execute(
            "CREATE INDEX IF NOT EXISTS idx_events_user_time ON events(telegram_user_id, created_at)"
        )
        connection.execute(
            "CREATE INDEX IF NOT EXISTS idx_events_type_time ON events(event_type, created_at)"
        )


def record_event(
    user_id: int,
    mode: str,
    event_type: str,
    message_type: str | None = None,
    db_path: str | None = None,
) -> None:
    with closing(connect(db_path)) as connection, connection:
        connection.execute(
            "CREATE TABLE IF NOT EXISTS events (id INTEGER PRIMARY KEY AUTOINCREMENT, telegram_user_id INTEGER NOT NULL, mode TEXT NOT NULL, event_type TEXT NOT NULL, message_type TEXT, created_at TEXT NOT NULL DEFAULT CURRENT_TIMESTAMP)"
        )
        connection.execute(
            "INSERT INTO events (telegram_user_id, mode, event_type, message_type) VALUES (?, ?, ?, ?)",
            (int(user_id), mode[:30], event_type[:50], message_type[:20] if message_type else None),
        )


def _period_start(period: str, now: dt.datetime | None = None) -> str:
    now = now or dt.datetime.now(dt.timezone.utc)
    days = {"day": 1, "week": 7, "month": 30}.get(period, 0)
    return (now - dt.timedelta(days=days)).strftime("%Y-%m-%d %H:%M:%S")


def user_metrics(user_id: int, period: str = "all", db_path: str | None = None) -> dict[str, object]:
    where = "telegram_user_id = ?"
    args: list[object] = [int(user_id)]
    if period != "all":
        where += " AND created_at >= ?"
        args.append(_period_start(period))
    with closing(connect(db_path)) as connection:
        rows = connection.execute(
            f"SELECT mode, event_type, message_type, COUNT(*) AS total FROM events WHERE {where} GROUP BY mode, event_type, message_type",
            args,
        ).fetchall()
    metrics: dict[str, object] = {
        "user_id": int(user_id), "period": period,
        "post_generations": 0, "idea_generations": 0, "post_revisions": 0,
        "generation_messages": 0, "training_messages": 0,
        "generation_message_types": {}, "training_message_types": {},
    }
    generation_types: dict[str, int] = {}
    training_types: dict[str, int] = {}
    for row in rows:
        event_type, message_type, total = row["event_type"], row["message_type"], int(row["total"])
        if event_type == "post_generation": metrics["post_generations"] = int(metrics["post_generations"]) + total
        elif event_type == "idea_generation": metrics["idea_generations"] = int(metrics["idea_generations"]) + total
        elif event_type == "post_revision": metrics["post_revisions"] = int(metrics["post_revisions"]) + total
        elif event_type == "user_message":
            target = generation_types if row["mode"] == "generation" else training_types
            if row["mode"] == "generation": metrics["generation_messages"] = int(metrics["generation_messages"]) + total
            elif row["mode"] == "training": metrics["training_messages"] = int(metrics["training_messages"]) + total
            if message_type: target[str(message_type)] = target.get(str(message_type), 0) + total
    metrics["generation_message_types"] = generation_types
    metrics["training_message_types"] = training_types
    return metrics


def all_metrics(period: str = "all", db_path: str | None = None) -> dict[str, object]:
    """Return owner-facing aggregate metrics from per-user events."""
    where = ""
    args: list[object] = []
    if period != "all":
        where = " WHERE created_at >= ?"
        args.append(_period_start(period))
    with closing(connect(db_path)) as connection:
        row = connection.execute(
            f"""SELECT COUNT(DISTINCT telegram_user_id) AS users,
                COUNT(DISTINCT CASE WHEN event_type = 'user_message' THEN telegram_user_id END) AS active_users,
                SUM(CASE WHEN event_type = 'post_generation' THEN 1 ELSE 0 END) AS post_generations,
                SUM(CASE WHEN event_type = 'idea_generation' THEN 1 ELSE 0 END) AS idea_generations,
                SUM(CASE WHEN event_type = 'post_revision' THEN 1 ELSE 0 END) AS post_revisions,
                SUM(CASE WHEN event_type = 'user_message' AND mode = 'generation' THEN 1 ELSE 0 END) AS generation_messages,
                SUM(CASE WHEN event_type = 'user_message' AND mode = 'training' THEN 1 ELSE 0 END) AS training_messages
             FROM events{where}""", args
        ).fetchone()
        types = connection.execute(
            f"SELECT mode, message_type, COUNT(*) AS total FROM events WHERE event_type='user_message' AND message_type IS NOT NULL{(' AND created_at >= ?' if period != 'all' else '')} GROUP BY mode, message_type",
            args,
        ).fetchall()
    result = {key: int(row[key] or 0) for key in ("users", "active_users", "post_generations", "idea_generations", "post_revisions", "generation_messages", "training_messages")}
    result["message_types"] = {(str(r["mode"]), str(r["message_type"])): int(r["total"]) for r in types}
    result["period"] = period
    return result


def _html_table(headers: list[str], rows: list[list[object]]) -> str:
    header = "".join(f"<th>{h}</th>" for h in headers)
    body = "".join("<tr>" + "".join(f"<td>{v}</td>" for v in row) + "</tr>" for row in rows)
    return f"<table><thead><tr>{header}</tr></thead><tbody>{body}</tbody></table>"


def render_report(period: str = "all", db_path: str | None = None) -> str:
    labels = {"day": "Сегодня", "week": "7 дней", "month": "30 дней", "all": "Всё время"}
    metrics_by_period = {key: all_metrics(key, db_path) for key in labels}
    titles = ["Сегодня", "7 дней", "30 дней", "Всё время"]

    def table(title: str, metric_rows: list[tuple[str, str]]) -> str:
        rows = [[label, *(metrics_by_period[key][metric] for key in labels)] for label, metric in metric_rows]
        return "<h3>" + title + "</h3>" + _html_table(["Показатель", *titles], rows)

    def table(title: str, metric_rows: list[tuple[str, str]]) -> str:
        rows = [[label, *(metrics_by_period[key][metric] for key in labels)] for label, metric in metric_rows]
        return "<h3>" + title + "</h3>" + _html_table(["Показатель", *titles], rows)

    type_names = sorted({key[1] for metrics in metrics_by_period.values() for key in metrics["message_types"]})
    generation_rows = [[kind, *(metrics_by_period[p]["message_types"].get(("generation", kind), 0) for p in labels)] for kind in type_names]
    training_type_rows = [[kind, *(metrics_by_period[p]["message_types"].get(("training", kind), 0) for p in labels)] for kind in type_names]
    if not generation_rows:
        generation_rows = [["Нет данных", 0, 0, 0, 0]]
        training_type_rows = [["Нет данных", 0, 0, 0, 0]]

    return (
        "<h2>📊 Статистика бота</h2>"
        + table("Пользователи", [("Активные", "active_users")])
        + table("Генерация", [("Посты", "post_generations"), ("Идеи", "idea_generations"), ("Правки", "post_revisions"), ("Сообщения", "generation_messages")])
        + "<h3>Типы сообщений в генерации</h3>" + _html_table(["Тип", *titles], generation_rows)
        + table("Обучение", [("Сообщения", "training_messages")])
        + "<h3>Типы сообщений в обучении</h3>" + _html_table(["Тип", *titles], training_type_rows)
    )