import importlib.util
from pathlib import Path
import subprocess
import sys
import json
import pytest


def updater():
    path=Path(__file__).resolve().parents[1]/'deploy/update.py'
    spec=importlib.util.spec_from_file_location('linux_updater',path)
    module=importlib.util.module_from_spec(spec);spec.loader.exec_module(module)
    return module


class Commands:
    def __init__(self, *, dirty=False, same=False, diverged=False, failed=None, states=None):
        self.calls=[];self.dirty=dirty;self.same=same;self.diverged=diverged
        self.failed=failed;self.states=states or ['active','active']

    def __call__(self,*args):
        self.calls.append(args)
        if self.failed and self.failed(args):raise RuntimeError('injected failure')
        if args[0]=='git':
            cmd=args[3:]
            if cmd[0]=='status':return ' M edited.py' if self.dirty else ''
            if cmd==('rev-parse','HEAD'):return 'a'*40
            if cmd[0]=='rev-parse':return 'origin/main' if '--abbrev-ref' in cmd else ('a' if self.same else 'b')*40
            if cmd[0]=='merge-base' and self.diverged:raise RuntimeError('not fast forward')
        if args[:2]==('systemctl','show'):
            return self.states[0 if 'worker' in args[-1] else 1]
        return ''


def test_plan_has_no_mutations():
    module=updater()
    result=subprocess.run([sys.executable,module.__file__,'--dry-run'],capture_output=True,text=True,check=True)
    assert json.loads(result.stdout)['status']=='PLAN'


@pytest.mark.parametrize('kwargs',[{'dirty':True},{'diverged':True}])
def test_refuses_local_changes_or_divergence_before_stopping(kwargs):
    module=updater();commands=Commands(**kwargs)
    with pytest.raises(RuntimeError):module.update(execute=commands)
    assert not any(c[0]=='systemctl' for c in commands.calls)


def test_same_revision_is_installed_after_bootstrap_pull(monkeypatch):
    module=updater();commands=Commands(same=True)
    monkeypatch.setattr(module,'trusted',lambda root:None)
    assert module.update(execute=commands)['status']=='UPDATED'
    assert any('pip' in c for c in commands.calls)


@pytest.mark.parametrize('states,started',[(['active','active'],['api','worker']),(['active','inactive'],['worker']),(['inactive','inactive'],[])])
def test_update_order_and_preserves_inactive_services(monkeypatch,states,started):
    module=updater();commands=Commands(states=states)
    monkeypatch.setattr(module,'trusted',lambda root:None)
    result=module.update(execute=commands)
    assert result['status']=='UPDATED'
    calls=commands.calls
    stops=[c for c in calls if c[:2]==('systemctl','stop')]
    assert stops==[('systemctl','stop',s) for s in module.SERVICES]
    merged=next(i for i,c in enumerate(calls) if c[0]=='git' and c[3]=='merge')
    installed=next(i for i,c in enumerate(calls) if 'pip' in c)
    assert calls.index(stops[-1])<merged<installed
    assert [c[-1].split('-')[-1].split('.')[0] for c in calls if c[:2]==('systemctl','start')]==started
    assert not any('enable' in c or 'reset' in c or 'clean' in c for c in calls)


@pytest.mark.parametrize('failure',['install','start'])
def test_failure_keeps_both_services_stopped(monkeypatch,failure):
    module=updater()
    commands=Commands(failed=lambda c: ('pip' in c) if failure=='install' else c[:2]==('systemctl','start'))
    monkeypatch.setattr(module,'trusted',lambda root:None)
    with pytest.raises(RuntimeError):module.update(execute=commands)
    assert commands.calls[-1]==('systemctl','stop',*module.SERVICES)


def test_fetch_failure_does_not_stop_services():
    module=updater();commands=Commands(failed=lambda c:'fetch' in c)
    with pytest.raises(RuntimeError):module.update(execute=commands)
    assert not any(c[0]=='systemctl' for c in commands.calls)