"""Tests for doctor's per-database journal-mode report.

`hermes doctor` lists each Hermes-managed database with its journal mode and
flags databases that are in WAL while the linked SQLite carries the WAL-reset
bug (https://sqlite.org/wal.html#walresetbug). The probe reads the file header
only — it never opens the database through the SQLite engine, because even a
read-only engine open creates -wal/-shm sidecar files next to a WAL database.
"""

import os
import re
import sqlite3

import pytest

import hermes_cli.doctor as doctor

VULNERABLE = (3, 50, 4)
FIXED_VERSIONS = [(3, 51, 3), (3, 52, 0), (3, 50, 7), (3, 44, 6)]

EXPOSED_TEXT = "exposed to the WAL-reset bug"


def _make_db(path, journal_mode=None):
    conn = sqlite3.connect(path)
    try:
        if journal_mode:
            conn.execute(f"PRAGMA journal_mode={journal_mode}")
        conn.execute("CREATE TABLE t (x INTEGER)")
        conn.commit()
    finally:
        conn.close()


def _sidecars(directory):
    return sorted(
        p.name for p in directory.iterdir() if p.name.endswith(("-wal", "-shm"))
    )


class TestReadJournalMode:
    def test_reads_wal(self, tmp_path):
        db = tmp_path / "state.db"
        _make_db(db, journal_mode="WAL")

        mode, error = doctor._read_journal_mode(db)

        assert mode == "wal"
        assert error is None

    def test_reads_rollback(self, tmp_path):
        db = tmp_path / "state.db"
        _make_db(db)

        mode, error = doctor._read_journal_mode(db)

        assert mode == "rollback"
        assert error is None

    def test_probe_creates_no_wal_sidecars(self, tmp_path):
        db = tmp_path / "state.db"
        _make_db(db, journal_mode="WAL")
        assert _sidecars(tmp_path) == []

        assert doctor._read_journal_mode(db) == ("wal", None)

        assert _sidecars(tmp_path) == []

    def test_missing_file_reports_error_and_does_not_create_it(self, tmp_path):
        db = tmp_path / "missing.db"

        mode, error = doctor._read_journal_mode(db)

        assert mode is None
        assert error
        assert not db.exists()

    def test_empty_file_reports_error(self, tmp_path):
        db = tmp_path / "state.db"
        db.touch()

        mode, error = doctor._read_journal_mode(db)

        assert mode is None
        assert error == "file is empty"

    def test_short_file_reports_error(self, tmp_path):
        db = tmp_path / "state.db"
        db.write_bytes(b"SQLite f")

        mode, error = doctor._read_journal_mode(db)

        assert mode is None
        assert "not a database" in error

    def test_corrupt_file_reports_error(self, tmp_path):
        db = tmp_path / "state.db"
        db.write_bytes(b"this is not a sqlite database" * 4)

        mode, error = doctor._read_journal_mode(db)

        assert mode is None
        assert "not a database" in error

    def test_locked_database_is_still_readable(self, tmp_path):
        db = tmp_path / "state.db"
        _make_db(db)
        holder = sqlite3.connect(db, isolation_level=None)
        try:
            holder.execute("BEGIN EXCLUSIVE")

            assert doctor._read_journal_mode(db) == ("rollback", None)
        finally:
            holder.close()

    @pytest.mark.skipif(os.name == "nt", reason="chmod is a no-op on Windows")
    @pytest.mark.skipif(os.geteuid() == 0, reason="root ignores file permissions")
    def test_read_only_directory_is_still_readable(self, tmp_path):
        db = tmp_path / "state.db"
        _make_db(db, journal_mode="WAL")
        os.chmod(tmp_path, 0o555)
        try:
            assert doctor._read_journal_mode(db) == ("wal", None)
        finally:
            os.chmod(tmp_path, 0o755)
        assert _sidecars(tmp_path) == []

    def test_does_not_mutate_database_files(self, tmp_path):
        wal_db = tmp_path / "wal.db"
        rollback_db = tmp_path / "plain.db"
        _make_db(wal_db, journal_mode="WAL")
        _make_db(rollback_db)
        wal_bytes = wal_db.read_bytes()
        rollback_bytes = rollback_db.read_bytes()

        assert doctor._read_journal_mode(wal_db) == ("wal", None)
        assert doctor._read_journal_mode(rollback_db) == ("rollback", None)

        assert wal_db.read_bytes() == wal_bytes
        assert rollback_db.read_bytes() == rollback_bytes
        assert _sidecars(tmp_path) == []


class TestReportDatabaseJournalModes:
    def test_vulnerable_runtime_wal_db_is_exposed(self, tmp_path, capsys):
        _make_db(tmp_path / "state.db", journal_mode="WAL")

        doctor._report_database_journal_modes(tmp_path, VULNERABLE)

        out = capsys.readouterr().out
        assert "state.db is in WAL mode" in out
        assert EXPOSED_TEXT in out

    def test_vulnerable_runtime_rollback_db_is_listed_not_exposed(self, tmp_path, capsys):
        _make_db(tmp_path / "state.db")

        doctor._report_database_journal_modes(tmp_path, VULNERABLE)

        out = capsys.readouterr().out
        assert "state.db: rollback journal mode" in out
        assert EXPOSED_TEXT not in out

    @pytest.mark.parametrize("version", FIXED_VERSIONS)
    def test_fixed_runtime_wal_db_is_not_exposed(self, tmp_path, capsys, version):
        _make_db(tmp_path / "state.db", journal_mode="WAL")

        doctor._report_database_journal_modes(tmp_path, version)

        out = capsys.readouterr().out
        assert "state.db: WAL journal mode" in out
        assert EXPOSED_TEXT not in out
        assert "⚠" not in out

    def test_lists_every_managed_database(self, tmp_path, capsys):
        _make_db(tmp_path / "state.db", journal_mode="WAL")
        _make_db(tmp_path / "projects.db")
        _make_db(tmp_path / "kanban.db")
        board = tmp_path / "kanban" / "boards" / "myboard"
        board.mkdir(parents=True)
        _make_db(board / "kanban.db", journal_mode="WAL")

        doctor._report_database_journal_modes(tmp_path, VULNERABLE)

        out = capsys.readouterr().out
        assert "state.db is in WAL mode" in out
        assert "projects.db: rollback journal mode" in out
        assert "kanban.db: rollback journal mode" in out
        assert "kanban/boards/myboard/kanban.db is in WAL mode" in out

    def test_missing_databases_are_skipped(self, tmp_path, capsys):
        doctor._report_database_journal_modes(tmp_path, VULNERABLE)

        out = capsys.readouterr().out
        assert "state.db" not in out
        assert EXPOSED_TEXT not in out

    def test_locked_database_does_not_crash_or_block(self, tmp_path, capsys):
        db = tmp_path / "state.db"
        _make_db(db)
        holder = sqlite3.connect(db, isolation_level=None)
        try:
            holder.execute("BEGIN EXCLUSIVE")

            doctor._report_database_journal_modes(tmp_path, VULNERABLE)
        finally:
            holder.close()

        out = capsys.readouterr().out
        assert "state.db: rollback journal mode" in out

    @pytest.mark.skipif(os.name == "nt", reason="chmod is a no-op on Windows")
    @pytest.mark.skipif(os.geteuid() == 0, reason="root ignores file permissions")
    def test_unreadable_database_does_not_crash(self, tmp_path, capsys):
        db = tmp_path / "state.db"
        _make_db(db)
        os.chmod(db, 0o000)
        try:
            doctor._report_database_journal_modes(tmp_path, VULNERABLE)
        finally:
            os.chmod(db, 0o644)

        out = capsys.readouterr().out
        assert "state.db: journal mode could not be read" in out
        assert "cannot rule out WAL exposure" in out

    def test_corrupt_database_does_not_crash(self, tmp_path, capsys):
        (tmp_path / "state.db").write_bytes(b"garbage bytes, not sqlite" * 8)

        doctor._report_database_journal_modes(tmp_path, VULNERABLE)

        out = capsys.readouterr().out
        assert "state.db: journal mode could not be read" in out

    def test_read_error_is_informational_on_fixed_runtime(self, tmp_path, capsys):
        (tmp_path / "state.db").write_bytes(b"garbage bytes, not sqlite" * 8)

        doctor._report_database_journal_modes(tmp_path, (3, 51, 3))

        out = capsys.readouterr().out
        assert "state.db: journal mode could not be read" in out
        assert "cannot rule out WAL exposure" not in out
        assert "⚠" not in out

    def test_report_creates_no_wal_sidecars(self, tmp_path, capsys):
        db = tmp_path / "state.db"
        _make_db(db, journal_mode="WAL")
        db_bytes = db.read_bytes()

        doctor._report_database_journal_modes(tmp_path, VULNERABLE)

        assert _sidecars(tmp_path) == []
        assert db.read_bytes() == db_bytes


class TestSizeAndRepairHint:
    def test_exposed_databases_report_size_and_repair_hint(self, tmp_path, capsys):
        db = tmp_path / "state.db"
        _make_db(db, journal_mode="WAL")
        doctor._report_database_journal_modes(tmp_path, VULNERABLE)
        out = capsys.readouterr().out
        # _format_size picks the unit (a fresh test DB is KB-scale).
        assert re.search(r"\(\d[\d.]* [KMGT]?B\)", out)
        assert "To clear the exposure:" in out

    def test_no_repair_hint_when_nothing_is_exposed(self, tmp_path, capsys):
        _make_db(tmp_path / "state.db", journal_mode="DELETE")
        doctor._report_database_journal_modes(tmp_path, VULNERABLE)
        assert "To clear the exposure:" not in capsys.readouterr().out

    def test_no_repair_hint_on_a_fixed_runtime(self, tmp_path, capsys):
        _make_db(tmp_path / "state.db", journal_mode="WAL")
        doctor._report_database_journal_modes(tmp_path, FIXED_VERSIONS[0])
        assert "To clear the exposure:" not in capsys.readouterr().out

    def test_size_failure_does_not_crash(self, tmp_path, capsys):
        assert doctor._format_db_size(tmp_path / "gone.db") == "size unknown"