# Copyright (c) 2026 Krzysztof Rudnicki. MIT licence.
"""Family A: who uses which commands, how often, and which nobody uses.

Counts include every source. "How many times was !papież used" is answered
by all three classes of row -- a reconstructed invocation still happened.
Only the questions that need an hour or a duration narrow to ``live``, and
those live in ``hours`` and ``health``.
"""

from __future__ import annotations

from dataclasses import dataclass
from typing import TYPE_CHECKING, Final

if TYPE_CHECKING:
    import sqlite3
    from collections.abc import Sequence

    from signal_bot.analytics.scope import Scope


@dataclass(frozen=True, slots=True)
class CommandUse:
    """One command, and everything countable about it."""

    command: str
    uses: int
    people: int
    ok: int
    refused: int
    errors: int
    first_day: str
    last_day: str

    @property
    def failure_rate(self) -> float:
        """Share of attempts that crashed. Refusals are not failures."""
        return self.errors / self.uses if self.uses else 0.0

    @property
    def refusal_rate(self) -> float:
        """Share of attempts a gate turned away.

        High is not popular, it is mis-tuned: it means people keep asking
        and keep being told no.
        """
        return self.refused / self.uses if self.uses else 0.0


@dataclass(frozen=True, slots=True)
class PersonUse:
    """One person's total, by uuid. Names are attached by the caller."""

    uuid: str
    uses: int
    commands: int
    favourite: str


BY_COMMAND_SQL: Final = """
SELECT command,
       COUNT(*)                                        AS uses,
       COUNT(DISTINCT user_uuid)                       AS people,
       SUM(outcome = 'ok')                             AS ok,
       SUM(outcome LIKE 'refused_%')                   AS refused,
       SUM(outcome = 'error')                          AS errors,
       MIN(day)                                        AS first_day,
       MAX(day)                                        AS last_day
FROM command_events
WHERE (:group IS NULL OR group_id = :group)
  AND outcome != 'unknown_word'
GROUP BY command
ORDER BY uses DESC, command
"""

BY_PERSON_SQL: Final = """
SELECT user_uuid,
       COUNT(*)                  AS uses,
       COUNT(DISTINCT command)   AS commands
FROM command_events
WHERE (:group IS NULL OR group_id = :group)
  AND outcome = 'ok'
GROUP BY user_uuid
ORDER BY uses DESC, user_uuid
"""

FAVOURITE_SQL: Final = """
SELECT user_uuid, command, COUNT(*) AS uses
FROM command_events
WHERE (:group IS NULL OR group_id = :group)
  AND outcome = 'ok'
GROUP BY user_uuid, command
ORDER BY user_uuid, uses DESC, command
"""

MATRIX_SQL: Final = """
SELECT user_uuid, command, COUNT(*) AS uses
FROM command_events
WHERE (:group IS NULL OR group_id = :group)
  AND outcome = 'ok'
GROUP BY user_uuid, command
ORDER BY user_uuid, command
"""

TOTALS_SQL: Final = """
SELECT COUNT(*)                  AS attempts,
       SUM(outcome = 'ok')       AS ok,
       COUNT(DISTINCT user_uuid) AS people,
       COUNT(DISTINCT command)   AS commands
FROM command_events
WHERE (:group IS NULL OR group_id = :group)
  AND outcome != 'unknown_word'
"""


def by_command(conn: sqlite3.Connection, scope: Scope) -> list[CommandUse]:
    """Every command that has ever been attempted, most used first."""
    return [
        CommandUse(
            command=str(row["command"]),
            uses=int(row["uses"]),
            people=int(row["people"]),
            ok=int(row["ok"] or 0),
            refused=int(row["refused"] or 0),
            errors=int(row["errors"] or 0),
            first_day=str(row["first_day"]),
            last_day=str(row["last_day"]),
        )
        for row in conn.execute(BY_COMMAND_SQL, scope.params())
    ]


def _favourites(conn: sqlite3.Connection, scope: Scope) -> dict[str, str]:
    """Each person's most-used command.

    The query orders by uses within each person, so the first row seen for
    a uuid is the answer and the rest are skipped -- cheaper than a window
    function and portable to the ancient sqlite a container might carry.
    """
    best: dict[str, str] = {}
    for row in conn.execute(FAVOURITE_SQL, scope.params()):
        best.setdefault(str(row["user_uuid"]), str(row["command"]))
    return best


def by_person(conn: sqlite3.Connection, scope: Scope) -> list[PersonUse]:
    """Who uses the bot, by uuid and most active first.

    Deliberately returns uuids. Turning one into a name is the caller's job
    and a different rule in each place: the group chat may name only people
    whose display name has been seen, the management page may show
    everyone, and neither may print a raw uuid or a phone number.
    """
    favourites = _favourites(conn, scope)
    return [
        PersonUse(
            uuid=str(row["user_uuid"]),
            uses=int(row["uses"]),
            commands=int(row["commands"]),
            favourite=favourites.get(str(row["user_uuid"]), ""),
        )
        for row in conn.execute(BY_PERSON_SQL, scope.params())
    ]


def matrix(conn: sqlite3.Connection, scope: Scope) -> list[tuple[str, str, int]]:
    """Every (person, command, count) triple, for the heatmap on the page.

    Never posted into a group -- a per-person breakdown of everybody's
    habits is a management-page thing.
    """
    return [
        (str(row["user_uuid"]), str(row["command"]), int(row["uses"]))
        for row in conn.execute(MATRIX_SQL, scope.params())
    ]


def totals(conn: sqlite3.Connection, scope: Scope) -> dict[str, int]:
    """Attempts, successes, distinct people and distinct commands."""
    row = conn.execute(TOTALS_SQL, scope.params()).fetchone()
    return {
        "attempts": int(row["attempts"] or 0),
        "ok": int(row["ok"] or 0),
        "people": int(row["people"] or 0),
        "commands": int(row["commands"] or 0),
    }


def never_used(known: Sequence[str], used: Sequence[CommandUse]) -> list[str]:
    """Registered commands with no recorded attempt at all.

    Takes the registry's list rather than reading it, because which commands
    exist depends on the group -- the album's are registered only where the
    album is -- and this module must not know that.
    """
    seen = {use.command for use in used}
    return sorted(name for name in known if name not in seen)