"""Tests for fingerprint-based incremental glean skipping (issue #30).

Verifies that _glean_files() (and its public wrappers) skip local files whose
mtime+size fingerprint has not changed since the last glean, and that force=True
bypasses that check.
"""
from __future__ import annotations

import sqlite3
import time
from pathlib import Path

import pytest

from app.glean.pipeline import (
    _fingerprint,
    _fp_unchanged,
    _save_fingerprint,
    ensure_schema,
    glean_dir,
    glean_file,
)
from app.glean.base import now_iso


# ── Fixtures ──────────────────────────────────────────────────────────────────

@pytest.fixture()
def db_path(tmp_path: Path) -> Path:
    path = tmp_path / "test.db"
    ensure_schema(path)
    return path


@pytest.fixture()
def log_file(tmp_path: Path) -> Path:
    """A minimal plaintext log file."""
    f = tmp_path / "test.log"
    f.write_text("May 24 10:00:00 heimdall kernel: test message\n")
    return f


# ── Unit: fingerprint helpers ──────────────────────────────────────────────────

class TestFingerprintHelpers:
    def test_fingerprint_returns_mtime_and_size(self, log_file: Path) -> None:
        mtime, size = _fingerprint(log_file)
        st = log_file.stat()
        assert mtime == st.st_mtime
        assert size == st.st_size

    def test_fp_unchanged_returns_false_when_no_record(self, db_path: Path, log_file: Path) -> None:
        conn = sqlite3.connect(str(db_path))
        conn.row_factory = sqlite3.Row
        mtime, size = _fingerprint(log_file)
        assert _fp_unchanged(conn, log_file, mtime, size) is False
        conn.close()

    def test_fp_unchanged_returns_true_after_save(self, db_path: Path, log_file: Path) -> None:
        conn = sqlite3.connect(str(db_path))
        conn.row_factory = sqlite3.Row
        mtime, size = _fingerprint(log_file)
        _save_fingerprint(conn, log_file, mtime, size, now_iso())
        conn.commit()
        assert _fp_unchanged(conn, log_file, mtime, size) is True
        conn.close()

    def test_fp_unchanged_returns_false_on_size_change(self, db_path: Path, log_file: Path) -> None:
        conn = sqlite3.connect(str(db_path))
        conn.row_factory = sqlite3.Row
        mtime, size = _fingerprint(log_file)
        _save_fingerprint(conn, log_file, mtime, size, now_iso())
        conn.commit()
        # Simulate size change (new content appended)
        assert _fp_unchanged(conn, log_file, mtime, size + 1) is False
        conn.close()

    def test_fp_unchanged_returns_false_on_mtime_change(self, db_path: Path, log_file: Path) -> None:
        conn = sqlite3.connect(str(db_path))
        conn.row_factory = sqlite3.Row
        mtime, size = _fingerprint(log_file)
        _save_fingerprint(conn, log_file, mtime, size, now_iso())
        conn.commit()
        assert _fp_unchanged(conn, log_file, mtime + 1.0, size) is False
        conn.close()

    def test_save_fingerprint_upserts(self, db_path: Path, log_file: Path) -> None:
        """Second save with different values replaces the first (UPSERT semantics)."""
        conn = sqlite3.connect(str(db_path))
        _save_fingerprint(conn, log_file, 1000.0, 100, "2026-01-01T00:00:00Z")
        conn.commit()
        _save_fingerprint(conn, log_file, 2000.0, 200, "2026-01-02T00:00:00Z")
        conn.commit()
        row = conn.execute(
            "SELECT mtime, size FROM glean_fingerprints WHERE path = ?",
            (str(log_file),),
        ).fetchone()
        assert row == (2000.0, 200)
        conn.close()


# ── Integration: glean_file skipping ─────────────────────────────────────────

class TestGleanFileFingerprint:
    def test_first_glean_writes_fingerprint(self, db_path: Path, log_file: Path) -> None:
        glean_file(log_file, db_path)
        conn = sqlite3.connect(str(db_path))
        row = conn.execute(
            "SELECT mtime, size FROM glean_fingerprints WHERE path = ?",
            (str(log_file),),
        ).fetchone()
        conn.close()
        assert row is not None
        mtime, size = _fingerprint(log_file)
        assert row == (mtime, size)

    def test_second_glean_skips_unchanged_file(self, db_path: Path, log_file: Path) -> None:
        stats_first = glean_file(log_file, db_path)
        count_first = sum(stats_first.values())

        # Re-glean without touching the file — should produce 0 new entries.
        stats_second = glean_file(log_file, db_path)
        count_second = sum(stats_second.values())

        assert count_first >= 1, "First glean should find at least one entry"
        assert count_second == 0, "Second glean should skip unchanged file"

    def test_second_glean_runs_when_file_grows(self, db_path: Path, log_file: Path) -> None:
        glean_file(log_file, db_path)

        # Append a new line and update mtime by rewriting.
        original = log_file.read_text()
        log_file.write_text(original + "May 24 10:01:00 heimdall kernel: second message\n")

        stats_second = glean_file(log_file, db_path)
        # INSERT OR IGNORE means the original entry won't re-count, but parsing
        # does happen — at minimum the new line is processed.
        assert sum(stats_second.values()) >= 0  # glean ran (not skipped)

        # Confirm fingerprint updated to new size.
        conn = sqlite3.connect(str(db_path))
        row = conn.execute(
            "SELECT size FROM glean_fingerprints WHERE path = ?",
            (str(log_file),),
        ).fetchone()
        conn.close()
        assert row is not None
        assert row[0] == log_file.stat().st_size

    def test_force_bypasses_fingerprint(self, db_path: Path, log_file: Path) -> None:
        glean_file(log_file, db_path)

        # Without force: skipped.
        stats_no_force = glean_file(log_file, db_path)
        assert sum(stats_no_force.values()) == 0

        # With force: glean runs (INSERT OR IGNORE means count may be 0, but
        # we verify the fingerprint was re-saved with a fresh gleaned_at).
        conn_before = sqlite3.connect(str(db_path))
        ts_before = conn_before.execute(
            "SELECT gleaned_at FROM glean_fingerprints WHERE path = ?",
            (str(log_file),),
        ).fetchone()[0]
        conn_before.close()

        time.sleep(0.01)  # ensure gleaned_at advances
        glean_file(log_file, db_path, force=True)

        conn_after = sqlite3.connect(str(db_path))
        ts_after = conn_after.execute(
            "SELECT gleaned_at FROM glean_fingerprints WHERE path = ?",
            (str(log_file),),
        ).fetchone()[0]
        conn_after.close()

        assert ts_after > ts_before, "force=True should update gleaned_at timestamp"


# ── Integration: glean_dir skipping ──────────────────────────────────────────

class TestGleanDirFingerprint:
    def test_glean_dir_skips_unchanged_on_second_run(self, db_path: Path, tmp_path: Path) -> None:
        log1 = tmp_path / "a.log"
        log2 = tmp_path / "b.log"
        log1.write_text("May 24 10:00:00 heimdall kernel: msg one\n")
        log2.write_text("May 24 10:00:00 heimdall kernel: msg two\n")

        glean_dir(tmp_path, db_path)

        stats_second = glean_dir(tmp_path, db_path)
        assert sum(stats_second.values()) == 0, "Both unchanged files should be skipped"

    def test_glean_dir_force_reruns_all(self, db_path: Path, tmp_path: Path) -> None:
        log1 = tmp_path / "a.log"
        log1.write_text("May 24 10:00:00 heimdall kernel: msg one\n")

        glean_dir(tmp_path, db_path)

        # force=True: runs even though nothing changed; INSERT OR IGNORE keeps DB clean.
        conn_before = sqlite3.connect(str(db_path))
        ts_before = conn_before.execute(
            "SELECT gleaned_at FROM glean_fingerprints WHERE path = ?",
            (str(log1),),
        ).fetchone()[0]
        conn_before.close()

        time.sleep(0.01)
        glean_dir(tmp_path, db_path, force=True)

        conn_after = sqlite3.connect(str(db_path))
        ts_after = conn_after.execute(
            "SELECT gleaned_at FROM glean_fingerprints WHERE path = ?",
            (str(log1),),
        ).fetchone()[0]
        conn_after.close()

        assert ts_after > ts_before


# ── Schema: ensure fingerprints table created ─────────────────────────────────

class TestEnsureSchema:
    def test_fingerprints_table_exists_after_ensure_schema(self, tmp_path: Path) -> None:
        db = tmp_path / "fresh.db"
        ensure_schema(db)
        conn = sqlite3.connect(str(db))
        tables = {
            row[0]
            for row in conn.execute(
                "SELECT name FROM sqlite_master WHERE type='table'"
            ).fetchall()
        }
        conn.close()
        assert "glean_fingerprints" in tables

    def test_ensure_schema_idempotent(self, tmp_path: Path) -> None:
        """Calling ensure_schema twice on the same DB must not raise."""
        db = tmp_path / "fresh.db"
        ensure_schema(db)
        ensure_schema(db)  # second call — should be a no-op