"""Tests for setup-plan preserving existing plan.md (#2653)."""

import json
import os
import shutil
import subprocess
from pathlib import Path

import pytest

from tests.conftest import requires_bash

PROJECT_ROOT = Path(__file__).resolve().parent.parent
COMMON_SH = PROJECT_ROOT / "scripts" / "bash" / "common.sh"
SETUP_PLAN_SH = PROJECT_ROOT / "scripts" / "bash" / "setup-plan.sh"
COMMON_PS = PROJECT_ROOT / "scripts" / "powershell" / "common.ps1"
SETUP_PLAN_PS = PROJECT_ROOT / "scripts" / "powershell" / "setup-plan.ps1"
PLAN_TEMPLATE = PROJECT_ROOT / "templates" / "plan-template.md"

HAS_PWSH = shutil.which("pwsh") is not None
_WINDOWS_POWERSHELL = (shutil.which("powershell.exe") or shutil.which("powershell")) if os.name == "nt" else None


def _install_bash_scripts(repo: Path) -> None:
    d = repo / ".specify" / "scripts" / "bash"
    d.mkdir(parents=True, exist_ok=True)
    shutil.copy(COMMON_SH, d / "common.sh")
    shutil.copy(SETUP_PLAN_SH, d / "setup-plan.sh")


def _install_ps_scripts(repo: Path) -> None:
    d = repo / ".specify" / "scripts" / "powershell"
    d.mkdir(parents=True, exist_ok=True)
    shutil.copy(COMMON_PS, d / "common.ps1")
    shutil.copy(SETUP_PLAN_PS, d / "setup-plan.ps1")


def _minimal_templates(repo: Path) -> None:
    tdir = repo / ".specify" / "templates"
    tdir.mkdir(parents=True, exist_ok=True)
    shutil.copy(PLAN_TEMPLATE, tdir / "plan-template.md")


def _write_feature_json(
    repo: Path, feature_directory: str = "specs/001-my-feature"
) -> None:
    (repo / ".specify" / "feature.json").write_text(
        json.dumps({"feature_directory": feature_directory}),
        encoding="utf-8",
    )


def _clean_env() -> dict[str, str]:
    env = os.environ.copy()
    for key in list(env):
        if key.startswith("SPECIFY_"):
            env.pop(key)
    return env


def _git_init(repo: Path) -> None:
    subprocess.run(["git", "init", "-q"], cwd=repo, check=True)
    subprocess.run(
        ["git", "config", "user.email", "test@example.com"], cwd=repo, check=True
    )
    subprocess.run(["git", "config", "user.name", "Test User"], cwd=repo, check=True)
    subprocess.run(
        ["git", "commit", "--allow-empty", "-m", "init", "-q"], cwd=repo, check=True
    )


@pytest.fixture
def plan_repo(tmp_path: Path) -> Path:
    repo = tmp_path / "proj"
    repo.mkdir()
    _git_init(repo)
    subprocess.run(
        ["git", "checkout", "-q", "-b", "001-my-feature"],
        cwd=repo,
        check=True,
    )
    (repo / ".specify").mkdir()
    _minimal_templates(repo)
    _install_bash_scripts(repo)
    _install_ps_scripts(repo)
    _write_feature_json(repo)
    return repo


# ── Bash tests ────────────────────────────────────────────────────────────


@requires_bash
def test_setup_plan_creates_plan_when_missing(plan_repo: Path) -> None:
    """First run must create plan.md from the template."""
    script = plan_repo / ".specify" / "scripts" / "bash" / "setup-plan.sh"
    result = subprocess.run(
        ["bash", str(script), "--json"],
        cwd=plan_repo,
        capture_output=True,
        text=True,
        check=False,
        env=_clean_env(),
    )
    assert result.returncode == 0, result.stderr
    data = json.loads(result.stdout)
    plan_path = Path(data["IMPL_PLAN"])
    assert plan_path.is_file()
    # Template content should be present
    content = plan_path.read_text(encoding="utf-8")
    assert len(content) > 0


@requires_bash
def test_setup_plan_preserves_existing_plan(plan_repo: Path) -> None:
    """Rerun must not overwrite an existing plan.md."""
    feat = plan_repo / "specs" / "001-my-feature"
    feat.mkdir(parents=True)
    existing_content = "# My carefully authored plan\n\nDo not overwrite me.\n"
    (feat / "plan.md").write_text(existing_content, encoding="utf-8")

    script = plan_repo / ".specify" / "scripts" / "bash" / "setup-plan.sh"
    result = subprocess.run(
        ["bash", str(script), "--json"],
        cwd=plan_repo,
        capture_output=True,
        text=True,
        check=False,
        env=_clean_env(),
    )
    assert result.returncode == 0, result.stderr
    # Plan must be unchanged
    assert (feat / "plan.md").read_text(encoding="utf-8") == existing_content


@requires_bash
def test_setup_plan_skip_message_on_stderr_in_json_mode(plan_repo: Path) -> None:
    """In --json mode, status messages must go to stderr, not stdout."""
    feat = plan_repo / "specs" / "001-my-feature"
    feat.mkdir(parents=True)
    (feat / "plan.md").write_text("# existing\n", encoding="utf-8")

    script = plan_repo / ".specify" / "scripts" / "bash" / "setup-plan.sh"
    result = subprocess.run(
        ["bash", str(script), "--json"],
        cwd=plan_repo,
        capture_output=True,
        text=True,
        check=False,
        env=_clean_env(),
    )
    assert result.returncode == 0, result.stderr
    # stdout must be valid JSON (no status messages mixed in)
    data = json.loads(result.stdout)
    assert "IMPL_PLAN" in data
    # The skip message should be on stderr
    assert "already exists" in result.stderr


@requires_bash
def test_setup_plan_json_parseable_on_first_run(plan_repo: Path) -> None:
    """In --json mode, first-run stdout must be parseable JSON (no status on stdout)."""
    script = plan_repo / ".specify" / "scripts" / "bash" / "setup-plan.sh"
    result = subprocess.run(
        ["bash", str(script), "--json"],
        cwd=plan_repo,
        capture_output=True,
        text=True,
        check=False,
        env=_clean_env(),
    )
    assert result.returncode == 0, result.stderr
    data = json.loads(result.stdout)
    assert "IMPL_PLAN" in data
    assert "Copied plan template" in result.stderr


# ── PowerShell tests ──────────────────────────────────────────────────────


@pytest.mark.skipif(not (HAS_PWSH or _WINDOWS_POWERSHELL), reason="no PowerShell available")
def test_ps_setup_plan_creates_plan_when_missing(plan_repo: Path) -> None:
    """First run must create plan.md from the template."""
    script = plan_repo / ".specify" / "scripts" / "powershell" / "setup-plan.ps1"
    exe = "pwsh" if HAS_PWSH else _WINDOWS_POWERSHELL
    result = subprocess.run(
        [exe, "-NoProfile", "-File", str(script), "-Json"],
        cwd=plan_repo,
        capture_output=True,
        text=True,
        check=False,
        env=_clean_env(),
    )
    assert result.returncode == 0, result.stderr
    data = json.loads(result.stdout)
    plan_path = Path(data["IMPL_PLAN"])
    assert plan_path.is_file()
    content = plan_path.read_text(encoding="utf-8")
    assert len(content) > 0


@pytest.mark.skipif(not (HAS_PWSH or _WINDOWS_POWERSHELL), reason="no PowerShell available")
def test_ps_setup_plan_preserves_existing_plan(plan_repo: Path) -> None:
    """Rerun must not overwrite an existing plan.md."""
    feat = plan_repo / "specs" / "001-my-feature"
    feat.mkdir(parents=True)
    existing_content = "# My carefully authored plan\n\nDo not overwrite me.\n"
    (feat / "plan.md").write_text(existing_content, encoding="utf-8")

    script = plan_repo / ".specify" / "scripts" / "powershell" / "setup-plan.ps1"
    exe = "pwsh" if HAS_PWSH else _WINDOWS_POWERSHELL
    result = subprocess.run(
        [exe, "-NoProfile", "-File", str(script), "-Json"],
        cwd=plan_repo,
        capture_output=True,
        text=True,
        check=False,
        env=_clean_env(),
    )
    assert result.returncode == 0, result.stderr
    assert (feat / "plan.md").read_text(encoding="utf-8") == existing_content
    # stdout must be valid JSON (no status messages mixed in)
    data = json.loads(result.stdout)
    assert "IMPL_PLAN" in data
    # The skip message should be on stderr
    assert "already exists" in result.stderr
