"""Unit tests for GalleryDLService._extract_errors_warnings and _truncate_log.

These are the save-time log transforms that feed the Downloads modal's
errors-only panel and prevent multi-MB stderr blobs from landing in JSONB.
"""
from app.services.gallery_dl import GalleryDLService


def test_extract_errors_warnings_filters_debug_and_info():
    stderr = (
        "[gallery-dl][debug] Version 1.31.10\n"
        "[patreon][info] campaign_id: 548223\n"
        "[urllib3.connectionpool][debug] https://example.com 'HEAD /' 200 0\n"
        "[download][error] Failed to download 01.part\n"
        "[downloader.http][warning] '404 OK' for 'https://example.com'\n"
        "[patreon][debug] skipping https://example.com/x\n"
    )
    result = GalleryDLService._extract_errors_warnings(stderr)
    lines = result.splitlines()
    assert len(lines) == 2
    assert "[download][error]" in lines[0]
    assert "[downloader.http][warning]" in lines[1]


def test_extract_errors_warnings_empty_when_clean_run():
    stderr = (
        "[gallery-dl][debug] Version 1.31.10\n"
        "[patreon][debug] skipping https://example.com/x\n"
    )
    assert GalleryDLService._extract_errors_warnings(stderr) == ""


def test_extract_errors_warnings_handles_empty_input():
    assert GalleryDLService._extract_errors_warnings("") == ""
    assert GalleryDLService._extract_errors_warnings(None) == ""


def test_truncate_log_passthrough_when_under_limit():
    small = "line\n" * 100
    assert GalleryDLService._truncate_log(small, max_bytes=10_000) == small


def test_truncate_log_elides_middle_when_oversized():
    large = ("x" * 100 + "\n") * 2000  # ~200KB
    truncated = GalleryDLService._truncate_log(large, max_bytes=10_000)

    assert len(truncated.encode("utf-8")) < len(large.encode("utf-8"))
    assert "lines elided" in truncated
    assert "bytes" in truncated
    # Head and tail preserved
    assert truncated.startswith("x")
    assert truncated.rstrip().endswith("x")


def test_truncate_log_handles_empty_and_none():
    assert GalleryDLService._truncate_log("") == ""
    assert GalleryDLService._truncate_log(None) is None