"""Tests for TUI launch-mode planning + arg parsing (pure, no Textual)."""

import pytest

from deerflow.tui.cli import LaunchPlan, build_parser, plan_launch


def plan(argv, *, stdin_tty=True, stdout_tty=True, env=None):
    return plan_launch(argv, stdin_isatty=stdin_tty, stdout_isatty=stdout_tty, env=env or {})


def test_top_level_help_points_to_extension_management():
    assert "deerflow extensions --help" in build_parser().format_help()


def test_bare_command_on_tty_launches_tui():
    p = plan([])
    assert p.mode == "tui"
    assert p.forced_tui is False
    assert p.transparent is False


def test_non_tty_with_no_message_falls_back_to_headless_help():
    p = plan([], stdin_tty=False, stdout_tty=False)
    assert p.mode == "headless-help"
    assert p.reason


def test_print_with_message():
    p = plan(["--print", "summarize this repo"])
    assert p.mode == "print"
    assert p.message == "summarize this repo"
    assert p.read_stdin is False


@pytest.mark.parametrize("mode", ["--print", "--json"])
def test_headless_recursion_limit(mode):
    p = plan(["--recursion-limit", "250", mode, "hello"])
    assert p.recursion_limit == 250


def test_headless_recursion_limit_is_optional():
    p = plan(["--print", "hello"])
    assert p.recursion_limit is None


@pytest.mark.parametrize("value", ["0", "-1", "not-an-integer"])
def test_headless_recursion_limit_must_be_positive(value):
    with pytest.raises(SystemExit):
        plan(["--recursion-limit", value, "--print", "hello"])


def test_recursion_limit_is_rejected_for_tui_mode():
    with pytest.raises(SystemExit):
        plan(["--recursion-limit", "250"])


def test_print_without_value_reads_stdin_when_piped():
    p = plan(["--print"], stdin_tty=False)
    assert p.mode == "print"
    assert p.read_stdin is True


def test_json_mode():
    p = plan(["--json", "hello"])
    assert p.mode == "json"
    assert p.message == "hello"


@pytest.mark.parametrize("mode", ["--print", "--json"])
def test_headless_unquoted_message_keeps_every_word(mode):
    """An unquoted message must not be truncated to its first word."""
    p = plan([mode, "summarize", "this", "repo"])
    assert p.mode == mode.removeprefix("--")
    assert p.message == "summarize this repo"
    assert p.read_stdin is False


@pytest.mark.parametrize("mode", ["--print", "--json"])
def test_headless_message_before_the_flag_is_used(mode):
    """Words before a bare --print/--json are the message, as with --cli."""
    p = plan(["summarize", "this", "repo", mode])
    assert p.mode == mode.removeprefix("--")
    assert p.message == "summarize this repo"
    assert p.read_stdin is False


@pytest.mark.parametrize("mode", ["--print", "--json"])
def test_headless_message_wins_over_piped_stdin(mode):
    p = plan(["hello", mode], stdin_tty=False)
    assert p.message == "hello"
    assert p.read_stdin is False


@pytest.mark.parametrize(
    "argv",
    [
        ["hello", "--print", "there"],
        ["--print", "hello", "--continue", "there"],
        ["hello", "--json", "there"],
    ],
)
def test_headless_message_split_around_the_flag_is_rejected(argv, capsys):
    """Word order across the flag is lost by argparse, so refuse rather than guess."""
    with pytest.raises(SystemExit) as exc:
        plan(argv)
    assert exc.value.code == 2
    assert "pass the message in one place" in capsys.readouterr().err


@pytest.mark.parametrize(
    "argv",
    [
        ["--print", "hello", "--json", "world"],
        ["--print", "--json", "hello"],
        ["--json", "hello", "--print"],
        ["hello", "--print", "--json"],
    ],
)
def test_print_and_json_together_are_rejected(argv, capsys):
    """Only one headless mode runs, so the other flag's message must not vanish."""
    with pytest.raises(SystemExit) as exc:
        plan(argv, stdin_tty=False)
    assert exc.value.code == 2
    assert "not allowed with argument" in capsys.readouterr().err


@pytest.mark.parametrize("mode", ["--print", "--json"])
def test_headless_blank_message_is_treated_as_missing(mode):
    p = plan([mode, "  "])
    assert p.mode == "headless-help"


def test_headless_help_documents_multi_word_messages():
    assert "--print [MESSAGE ...]" in build_parser().format_help()


def test_force_tui_even_without_tty():
    p = plan(["--tui"], stdin_tty=False, stdout_tty=False)
    assert p.mode == "tui"
    assert p.forced_tui is True


def test_env_var_forces_tui():
    p = plan([], stdin_tty=False, stdout_tty=False, env={"DEER_FLOW_TUI": "1"})
    assert p.mode == "tui"


def test_transparent_flag_is_carried_to_tui_plan():
    p = plan(["--tui-transparent"])
    assert p.mode == "tui"
    assert p.transparent is True


def test_transparent_env_is_carried_to_tui_plan():
    p = plan([], env={"DEER_FLOW_TUI_TRANSPARENT": "yes"})
    assert p.mode == "tui"
    assert p.transparent is True


def test_cli_flag_with_message_runs_print():
    p = plan(["--cli", "do", "this", "thing"])
    assert p.mode == "print"
    assert p.message == "do this thing"


def test_cli_flag_without_message_is_headless_help():
    p = plan(["--cli"])
    assert p.mode == "headless-help"


def test_cli_continue_runs_headless_reading_stdin():
    p = plan(["--cli", "--continue"], stdin_tty=False)
    assert p.mode == "print"
    assert p.read_stdin is True
    assert p.continue_recent is True


def test_cli_with_piped_stdin_runs_headless():
    p = plan(["--cli"], stdin_tty=False)
    assert p.mode == "print"
    assert p.read_stdin is True


def test_continue_recent_flag():
    p = plan(["--continue"])
    assert p.mode == "tui"
    assert p.continue_recent is True


def test_resume_specific_thread():
    p = plan(["--resume", "thread-abc"])
    assert p.mode == "tui"
    assert p.thread_id == "thread-abc"


def test_chat_subcommand_is_accepted():
    p = plan(["chat"])
    assert p.mode == "tui"


def test_chat_subcommand_with_print():
    p = plan(["chat", "--print", "hi"])
    assert p.mode == "print"
    assert p.message == "hi"


def test_positional_message_becomes_initial_tui_prompt():
    p = plan(["explain", "the", "codebase"])
    assert p.mode == "tui"
    assert p.message == "explain the codebase"


def test_plan_is_a_launch_plan_instance():
    assert isinstance(plan([]), LaunchPlan)