from __future__ import annotations

import os
from pathlib import Path
from tempfile import TemporaryDirectory

from django.test import SimpleTestCase

from pobsync.run_stats import collect_storage_stats, parse_rsync_stats, tree_usage


class RunStatsTests(SimpleTestCase):
    def test_parse_rsync_stats_extracts_counts_bytes_and_savings(self) -> None:
        stats = parse_rsync_stats(
            """
Number of files: 1,234 (reg: 1,200, dir: 34)
Number of created files: 12 (reg: 10, dir: 2)
Number of deleted files: 3
Number of regular files transferred: 8
Total file size: 1.50M bytes
Total transferred file size: 24.00K bytes
Literal data: 24.00K bytes
Matched data: 976.00K bytes
File list size: 8.00K
Total bytes sent: 10.00K
Total bytes received: 2.00K
sent 10.00K bytes  received 2.00K bytes  1.20K bytes/sec
total size is 1.50M  speedup is 125.00
"""
        )

        self.assertEqual(stats["files_total"], 1234)
        self.assertEqual(stats["files_created"], 12)
        self.assertEqual(stats["files_deleted"], 3)
        self.assertEqual(stats["files_transferred"], 8)
        self.assertEqual(stats["total_file_size_bytes"], 1_500_000)
        self.assertEqual(stats["total_transferred_file_size_bytes"], 24_000)
        self.assertEqual(stats["literal_data_bytes"], 24_000)
        self.assertEqual(stats["matched_data_bytes"], 976_000)
        self.assertEqual(stats["bytes_sent_received"], 12_000)
        self.assertEqual(stats["bytes_per_second"], 1_200)
        self.assertEqual(stats["speedup"], 125.0)
        self.assertEqual(stats["link_dest_estimated_savings_bytes"], 976_000)
        self.assertEqual(stats["link_dest_estimated_savings_ratio"], 0.976)

    def test_tree_usage_reports_hardlinked_files(self) -> None:
        with TemporaryDirectory() as tmp:
            root = Path(tmp)
            source = root / "source"
            linked = root / "linked"
            source.write_bytes(b"abc")
            os.link(source, linked)

            stats = tree_usage(root)

        self.assertEqual(stats["files"], 2)
        self.assertEqual(stats["apparent_size_bytes"], 6)
        self.assertEqual(stats["hardlinked_files"], 2)
        self.assertEqual(stats["hardlinked_apparent_size_bytes"], 6)
        self.assertEqual(stats["hardlink_apparent_ratio"], 1.0)
        self.assertFalse(stats["scan_limited"])

    def test_tree_usage_can_limit_large_scans(self) -> None:
        with TemporaryDirectory() as tmp:
            root = Path(tmp)
            for index in range(5):
                (root / f"file-{index}").write_bytes(b"x")

            stats = tree_usage(root, max_entries=2)

        self.assertEqual(stats["files"], 2)
        self.assertEqual(stats["entries_scanned"], 2)
        self.assertEqual(stats["max_entries"], 2)
        self.assertTrue(stats["scan_limited"])
        self.assertEqual(stats["apparent_size_bytes"], 2)

    def test_collect_storage_stats_marks_limited_snapshot_scan(self) -> None:
        with TemporaryDirectory() as tmp:
            root = Path(tmp)
            snapshot = root / "snapshot"
            snapshot.mkdir()
            for index in range(4):
                (snapshot / f"file-{index}").write_bytes(b"x")

            stats = collect_storage_stats(
                backup_root=root,
                snapshot_dir=snapshot,
                snapshot_max_entries=1,
            )

        self.assertEqual(stats["snapshot"]["files"], 1)
        self.assertEqual(stats["snapshot"]["entries_scanned"], 1)
        self.assertEqual(stats["snapshot"]["max_entries"], 1)
        self.assertTrue(stats["snapshot"]["scan_limited"])