#!/usr/bin/env python3

import contextlib
import importlib.util
import io
import pathlib
import tempfile
import unittest
from unittest import mock


_SCRIPT_PATH = pathlib.Path(__file__).with_name("offset-fixer.py")
_SPEC = importlib.util.spec_from_file_location("offset_fixer", _SCRIPT_PATH)
mod = importlib.util.module_from_spec(_SPEC)
assert _SPEC and _SPEC.loader
_SPEC.loader.exec_module(mod)


class OffsetFixerTest(unittest.TestCase):
    def test_format_time_string(self) -> None:
        entry = mod.SubtitleEntry(1, "hello\n", "01:02:03,250", "01:02:04,500")
        self.assertEqual(
            "01:02:03,250 --> 01:02:04,500",
            entry.formatTimeString(),
        )

    def test_shift_updates_start_and_end(self) -> None:
        entry = mod.SubtitleEntry(1, "hello\n", "00:00:10,000", "00:00:12,500")
        entry.shift(1.25)
        self.assertEqual(
            "00:00:11,250 --> 00:00:13,750",
            entry.formatTimeString(),
        )

    def test_main_writes_shifted_output(self) -> None:
        srt = (
            "1\n"
            "00:00:01,000 --> 00:00:02,000\n"
            "Hello\n"
            "\n"
            "2\n"
            "00:00:03,500 --> 00:00:04,250\n"
            "Bye\n"
            "\n"
        )
        with tempfile.TemporaryDirectory() as td:
            in_path = pathlib.Path(td) / "input.srt"
            out_path = pathlib.Path(td) / "output.srt"
            in_path.write_text(srt, encoding="utf-8")

            argv = [
                "offset-fixer.py",
                "--seconds",
                "1.5",
                "--file",
                str(in_path),
                "--outfile",
                str(out_path),
            ]
            with mock.patch("sys.argv", argv), contextlib.redirect_stdout(io.StringIO()):
                mod.main()

            output = out_path.read_text(encoding="utf-8")
            self.assertIn("00:00:02,500 --> 00:00:03,500", output)
            self.assertIn("00:00:05,000 --> 00:00:05,750", output)
            self.assertIn("Hello", output)
            self.assertIn("Bye", output)

    def test_main_strip_first_and_last(self) -> None:
        srt = (
            "1\n"
            "00:00:01,000 --> 00:00:02,000\n"
            "First subtitle\n"
            "\n"
            "2\n"
            "00:00:03,000 --> 00:00:04,000\n"
            "Last subtitle\n"
            "\n"
        )
        with tempfile.TemporaryDirectory() as td:
            in_path = pathlib.Path(td) / "input.srt"
            out_path = pathlib.Path(td) / "output.srt"
            in_path.write_text(srt, encoding="utf-8")

            argv = [
                "offset-fixer.py",
                "--seconds",
                "0",
                "--file",
                str(in_path),
                "--outfile",
                str(out_path),
                "--strip-first",
                "--strip-last",
            ]
            with mock.patch("sys.argv", argv), contextlib.redirect_stdout(io.StringIO()):
                mod.main()

            output = out_path.read_text(encoding="utf-8")
            self.assertNotIn("First subtitle", output)
            self.assertNotIn("Last subtitle", output)
            self.assertIn("00:00:01,000 --> 00:00:02,000", output)
            self.assertIn("00:00:03,000 --> 00:00:04,000", output)

    def test_main_inplace_creates_backup_and_updates_source(self) -> None:
        srt = (
            "1\n"
            "00:00:01,000 --> 00:00:02,000\n"
            "Keep me\n"
            "\n"
        )
        with tempfile.TemporaryDirectory() as td:
            in_path = pathlib.Path(td) / "input.srt"
            in_path.write_text(srt, encoding="utf-8")

            argv = [
                "offset-fixer.py",
                "--seconds",
                "0.5",
                "--file",
                str(in_path),
                "--inplace",
            ]
            with mock.patch("sys.argv", argv), contextlib.redirect_stdout(io.StringIO()):
                mod.main()

            backup_text = (pathlib.Path(str(in_path) + ".backup")).read_text(encoding="utf-8")
            updated_text = in_path.read_text(encoding="utf-8")
            self.assertIn("00:00:01,000 --> 00:00:02,000", backup_text)
            self.assertIn("00:00:01,500 --> 00:00:02,500", updated_text)
            self.assertIn("Keep me", updated_text)

    def test_main_inplace_rejects_outfile(self) -> None:
        srt = (
            "1\n"
            "00:00:01,000 --> 00:00:02,000\n"
            "Hello\n"
            "\n"
        )
        with tempfile.TemporaryDirectory() as td:
            in_path = pathlib.Path(td) / "input.srt"
            out_path = pathlib.Path(td) / "output.srt"
            in_path.write_text(srt, encoding="utf-8")

            argv = [
                "offset-fixer.py",
                "--seconds",
                "1",
                "--file",
                str(in_path),
                "--inplace",
                "--outfile",
                str(out_path),
            ]
            with mock.patch("sys.argv", argv), contextlib.redirect_stdout(io.StringIO()):
                with self.assertRaises(SystemExit) as exc:
                    mod.main()
            self.assertEqual(1, exc.exception.code)


if __name__ == "__main__":
    unittest.main()