package app_test

import (
	"context"
	"errors"
	"path/filepath"
	"strings"
	"testing"

	"proxyctl/internal/app"
	"proxyctl/internal/profile"
	"proxyctl/internal/target"
)

func TestApplicationSnapshotStructuresContextualTargetActions(t *testing.T) {
	states := []struct {
		id     string
		state  target.State
		action app.TargetActionKind
	}{
		{id: "disabled", state: target.Disabled, action: app.EnableTargetAction},
		{id: "enabled", state: target.Enabled, action: app.DisableTargetAction},
		{id: "external", state: target.External, action: app.ApplyProfileTargetAction},
		{id: "drifted", state: target.Drifted, action: app.ResolveDriftTargetAction},
	}
	adapters := make([]target.Target, 0, len(states))
	for _, item := range states {
		adapters = append(adapters, targetWithID{fakeTarget: &fakeTarget{available: true, state: item.state}, id: item.id})
	}
	application, err := app.NewWithTargets(profile.NewFileStore(filepath.Join(t.TempDir(), "profiles.json")), adapters)
	if err != nil {
		t.Fatal(err)
	}
	createAndActivate(t, application)
	if result := application.Dispatch(app.Intent{Kind: app.RefreshTargets}); result.Err != nil {
		t.Fatal(result.Err)
	}

	snapshot := application.Snapshot()
	for i, want := range states {
		got := snapshot.Targets[i]
		if got.PrimaryAction.Kind != want.action || !got.PrimaryAction.Available || got.PrimaryAction.DisabledReason != "" {
			t.Errorf("%s primary action = %#v, want available %v", want.state, got.PrimaryAction, want.action)
		}
	}
	drift := snapshot.Targets[3]
	if len(drift.DriftResolutionActions) != 2 || drift.DriftResolutionActions[0].Kind != app.ReapplyActiveProfileAction || drift.DriftResolutionActions[1].Kind != app.RestoreOriginalAction {
		t.Fatalf("Drift Resolution actions = %#v", drift.DriftResolutionActions)
	}
	for _, action := range drift.DriftResolutionActions {
		if !action.Available || action.DisabledReason != "" {
			t.Errorf("Drift Resolution action = %#v, want available", action)
		}
	}
}

func TestApplicationSnapshotMakesUnknownTargetStateStructurallyUnavailable(t *testing.T) {
	adapter := &fakeTarget{available: true}
	application, err := app.NewWithTargets(profile.NewFileStore(filepath.Join(t.TempDir(), "profiles.json")), []target.Target{adapter})
	if err != nil {
		t.Fatal(err)
	}
	createAndActivate(t, application)
	if result := application.Dispatch(app.Intent{Kind: app.RefreshTargets}); result.Err != nil {
		t.Fatal(result.Err)
	}

	got := application.Snapshot().Targets[0].PrimaryAction
	const reason = "Target actions are unavailable because this Target state is unknown"
	if got.Kind != 0 || got.Available || got.DisabledReason != reason {
		t.Fatalf("unknown-state action = %#v, want structurally unavailable with reason %q", got, reason)
	}
}

func TestApplicationDispatchesExplicitContextualTargetIntents(t *testing.T) {
	tests := []struct {
		name    string
		state   target.State
		intent  app.IntentKind
		enabled bool
	}{
		{name: "Enable", state: target.Disabled, intent: app.EnableTarget, enabled: true},
		{name: "Disable", state: target.Enabled, intent: app.DisableTarget, enabled: false},
		{name: "Apply Profile", state: target.External, intent: app.ApplyProfileToTarget, enabled: true},
		{name: "Reapply Active Profile", state: target.Drifted, intent: app.ReapplyActiveProfile, enabled: true},
		{name: "Restore Original", state: target.Drifted, intent: app.RestoreOriginal, enabled: false},
	}
	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			adapter := &fakeTarget{available: true, state: target.Disabled}
			application, err := app.NewWithTargets(profile.NewFileStore(filepath.Join(t.TempDir(), "profiles.json")), []target.Target{adapter})
			if err != nil {
				t.Fatal(err)
			}
			createAndActivate(t, application)
			adapter.state = test.state
			adapter.calls = nil
			if result := application.Dispatch(app.Intent{Kind: app.RefreshTargets}); result.Err != nil {
				t.Fatal(result.Err)
			}

			result := application.Dispatch(app.Intent{Kind: test.intent, TargetID: adapter.ID()})
			if result.Err != nil || len(adapter.calls) != 1 || adapter.calls[0] != test.enabled {
				t.Fatalf("result = %#v, SetDesired calls = %#v", result, adapter.calls)
			}
			wantState := target.Disabled
			if test.enabled {
				wantState = target.Enabled
			}
			if result.Snapshot.Targets[0].State != wantState {
				t.Fatalf("final state = %s, want %s", result.Snapshot.Targets[0].State, wantState)
			}
		})
	}
}

func TestApplicationRejectsContextualIntentWhenTargetStateChanged(t *testing.T) {
	adapter := &fakeTarget{available: true, state: target.External}
	application, err := app.NewWithTargets(profile.NewFileStore(filepath.Join(t.TempDir(), "profiles.json")), []target.Target{adapter})
	if err != nil {
		t.Fatal(err)
	}
	createAndActivate(t, application)
	if result := application.Dispatch(app.Intent{Kind: app.RefreshTargets}); result.Err != nil {
		t.Fatal(result.Err)
	}

	result := application.Dispatch(app.Intent{Kind: app.EnableTarget, TargetID: adapter.ID()})
	if result.Err == nil || !strings.Contains(result.Err.Error(), "External") || len(adapter.calls) != 0 {
		t.Fatalf("stale Enable intent = %#v, calls = %#v", result, adapter.calls)
	}
}

func TestApplicationReapplyPublishesTruthfulDriftWhenAdapterCannotConverge(t *testing.T) {
	adapter := &fakeTarget{available: true, state: target.Disabled}
	application, err := app.NewWithTargets(profile.NewFileStore(filepath.Join(t.TempDir(), "profiles.json")), []target.Target{adapter})
	if err != nil {
		t.Fatal(err)
	}
	createAndActivate(t, application)
	adapter.state = target.Drifted
	adapter.setState = target.Drifted
	adapter.calls = nil
	if result := application.Dispatch(app.Intent{Kind: app.RefreshTargets}); result.Err != nil {
		t.Fatal(result.Err)
	}

	result := application.Dispatch(app.Intent{Kind: app.ReapplyActiveProfile, TargetID: adapter.ID()})
	if result.Err != nil || result.Snapshot.Targets[0].State != target.Drifted || result.Progress[0].State != target.Drifted {
		t.Fatalf("truthful non-converged reapply = %#v", result)
	}
}

type changingAvailabilityTarget struct {
	*fakeTarget
	detections int
}

func (f *changingAvailabilityTarget) Detect(context.Context, *profile.Profile) target.Detection {
	f.detections++
	available := f.detections == 1
	return target.Detection{
		Availability: target.Availability{Available: available, Evidence: map[bool]string{true: "available", false: "no longer available"}[available]},
		Inspection:   target.Inspection{State: target.External, Evidence: "actual state"},
	}
}

func TestApplicationRechecksAvailabilityImmediatelyBeforeTargetMutation(t *testing.T) {
	base := &fakeTarget{available: true, state: target.External}
	adapter := &changingAvailabilityTarget{fakeTarget: base}
	application, err := app.NewWithTargets(profile.NewFileStore(filepath.Join(t.TempDir(), "profiles.json")), []target.Target{adapter})
	if err != nil {
		t.Fatal(err)
	}
	createAndActivate(t, application)
	if result := application.Dispatch(app.Intent{Kind: app.RefreshTargets}); result.Err != nil {
		t.Fatal(result.Err)
	}
	if before := application.Snapshot().Targets[0]; !before.Available || !before.PrimaryAction.Available {
		t.Fatalf("initial detection = %#v, want available action", before)
	}

	result := application.Dispatch(app.Intent{Kind: app.ApplyProfileToTarget, TargetID: adapter.ID()})
	const reason = "Target actions are unavailable because this Target is unavailable"
	if result.Err == nil || result.Err.Error() != reason || len(base.calls) != 0 {
		t.Fatalf("available-to-unavailable result = %#v, SetDesired calls = %#v", result, base.calls)
	}
	if got := result.Snapshot.Targets[0]; got.Available || got.AvailabilityEvidence != "no longer available" || got.PrimaryAction.Available || got.PrimaryAction.DisabledReason != reason {
		t.Fatalf("published targeted detection = %#v", got)
	}
}

type failedDetectionTarget struct {
	*fakeTarget
}

func (f failedDetectionTarget) Detect(context.Context, *profile.Profile) target.Detection {
	return target.Detection{
		Availability: target.Availability{Available: true, Evidence: "detected"},
		Inspection:   target.Inspection{State: f.state, Evidence: "actual state"},
		Err:          errors.New("detection failed"),
	}
}

func TestApplicationRejectsStructuredUnavailableActionWithoutAdapterMutation(t *testing.T) {
	adapter := &fakeTarget{available: false, state: target.External}
	application, err := app.NewWithTargets(profile.NewFileStore(filepath.Join(t.TempDir(), "profiles.json")), []target.Target{adapter})
	if err != nil {
		t.Fatal(err)
	}
	createAndActivate(t, application)
	adapter.calls = nil
	if result := application.Dispatch(app.Intent{Kind: app.RefreshTargets}); result.Err != nil {
		t.Fatal(result.Err)
	}
	if action := application.Snapshot().Targets[0].PrimaryAction; action.Available || !strings.Contains(action.DisabledReason, "unavailable") {
		t.Fatalf("unavailable action = %#v", action)
	}

	result := application.Dispatch(app.Intent{Kind: app.ApplyProfileToTarget, TargetID: adapter.ID()})
	if result.Err == nil || !strings.Contains(result.Err.Error(), "unavailable") || len(adapter.calls) != 0 {
		t.Fatalf("unavailable action result = %#v, calls=%#v", result, adapter.calls)
	}
}

func TestApplicationValidatesEveryStructuredDisabledReasonBeforeAdapterMutation(t *testing.T) {
	assertRejected := func(t *testing.T, application *app.Application, adapter *fakeTarget, intent app.Intent, reason string) {
		t.Helper()
		adapter.calls = nil
		result := application.Dispatch(intent)
		if result.Err == nil || !strings.Contains(result.Err.Error(), reason) || len(adapter.calls) != 0 {
			t.Fatalf("disabled action result = %#v, calls = %#v, want reason containing %q", result, adapter.calls, reason)
		}
	}

	t.Run("failed check", func(t *testing.T) {
		adapter := &fakeTarget{available: true, state: target.Disabled}
		application, err := app.NewWithTargets(profile.NewFileStore(filepath.Join(t.TempDir(), "profiles.json")), []target.Target{failedDetectionTarget{fakeTarget: adapter}})
		if err != nil {
			t.Fatal(err)
		}
		createAndActivate(t, application)
		if result := application.Dispatch(app.Intent{Kind: app.RefreshTargets}); result.Err == nil {
			t.Fatal("Target check unexpectedly succeeded")
		}
		assertRejected(t, application, adapter, app.Intent{Kind: app.EnableTarget, TargetID: adapter.ID()}, "check failed")
	})

	t.Run("unavailable Drift Resolution", func(t *testing.T) {
		adapter := &fakeTarget{available: false, state: target.Drifted}
		application, err := app.NewWithTargets(profile.NewFileStore(filepath.Join(t.TempDir(), "profiles.json")), []target.Target{adapter})
		if err != nil {
			t.Fatal(err)
		}
		createAndActivate(t, application)
		if result := application.Dispatch(app.Intent{Kind: app.RefreshTargets}); result.Err != nil {
			t.Fatal(result.Err)
		}
		assertRejected(t, application, adapter, app.Intent{Kind: app.RestoreOriginal, TargetID: adapter.ID()}, "unavailable")
	})
}

func TestApplicationRejectsProfileDependentIntentsWithoutActiveProfile(t *testing.T) {
	for _, test := range []struct {
		name   string
		state  target.State
		intent app.IntentKind
	}{
		{name: "Apply Profile", state: target.External, intent: app.ApplyProfileToTarget},
		{name: "Reapply Active Profile", state: target.Drifted, intent: app.ReapplyActiveProfile},
	} {
		t.Run(test.name, func(t *testing.T) {
			adapter := &fakeTarget{available: true, state: test.state}
			application, err := app.NewWithTargets(profile.NewFileStore(filepath.Join(t.TempDir(), "profiles.json")), []target.Target{adapter})
			if err != nil {
				t.Fatal(err)
			}
			if result := application.Dispatch(app.Intent{Kind: app.RefreshTargets}); result.Err != nil {
				t.Fatal(result.Err)
			}
			result := application.Dispatch(app.Intent{Kind: test.intent, TargetID: adapter.ID()})
			if result.Err == nil || !strings.Contains(result.Err.Error(), "no Active Profile") || len(adapter.calls) != 0 {
				t.Fatalf("missing Active Profile result = %#v, calls=%#v", result, adapter.calls)
			}
		})
	}
}

func TestApplicationRevalidatesRestoreAfterOwnershipSensitiveStateChange(t *testing.T) {
	adapter := &fakeTarget{available: true, state: target.Drifted}
	application, err := app.NewWithTargets(profile.NewFileStore(filepath.Join(t.TempDir(), "profiles.json")), []target.Target{adapter})
	if err != nil {
		t.Fatal(err)
	}
	createAndActivate(t, application)
	if result := application.Dispatch(app.Intent{Kind: app.RefreshTargets}); result.Err != nil {
		t.Fatal(result.Err)
	}

	// Model ownership loss as a fresh inspection becoming External between the
	// displayed Drift Resolution and dispatch. The stale Restore intent must not
	// reach SetDesired, where it could otherwise overwrite external state.
	adapter.state = target.External
	adapter.calls = nil
	result := application.Dispatch(app.Intent{Kind: app.RestoreOriginal, TargetID: adapter.ID()})
	if result.Err == nil || !strings.Contains(result.Err.Error(), "External") || len(adapter.calls) != 0 || result.Snapshot.Targets[0].State != target.External {
		t.Fatalf("stale Restore result = %#v, calls = %#v", result, adapter.calls)
	}
}

func TestApplicationReapplyAndRestoreFailuresPublishFreshDriftedState(t *testing.T) {
	for _, test := range []struct {
		name   string
		intent app.IntentKind
		err    string
	}{
		{name: "reapply", intent: app.ReapplyActiveProfile, err: "write failed"},
		{name: "restore ownership loss", intent: app.RestoreOriginal, err: "restoration evidence is insufficient; refusing to overwrite external changes"},
	} {
		t.Run(test.name, func(t *testing.T) {
			adapter := &fakeTarget{available: true, state: target.Drifted, setErr: errors.New(test.err)}
			application, err := app.NewWithTargets(profile.NewFileStore(filepath.Join(t.TempDir(), "profiles.json")), []target.Target{adapter})
			if err != nil {
				t.Fatal(err)
			}
			createAndActivate(t, application)
			if result := application.Dispatch(app.Intent{Kind: app.RefreshTargets}); result.Err != nil {
				t.Fatal(result.Err)
			}

			result := application.Dispatch(app.Intent{Kind: test.intent, TargetID: adapter.ID()})
			if result.Err == nil || !strings.Contains(result.Err.Error(), test.err) || result.Snapshot.Targets[0].State != target.Drifted || result.Snapshot.Targets[0].Evidence != "actual state" {
				t.Fatalf("failure = %#v", result)
			}
			if len(adapter.calls) != 1 || adapter.calls[0] != (test.intent == app.ReapplyActiveProfile) {
				t.Fatalf("SetDesired calls = %#v", adapter.calls)
			}
		})
	}
}

func TestApplicationSnapshotDisablesProfileDependentActionsWithoutActiveProfile(t *testing.T) {
	adapters := []target.Target{
		targetWithID{fakeTarget: &fakeTarget{available: true, state: target.Disabled}, id: "disabled"},
		targetWithID{fakeTarget: &fakeTarget{available: true, state: target.External}, id: "external"},
		targetWithID{fakeTarget: &fakeTarget{available: true, state: target.Drifted}, id: "drifted"},
	}
	application, err := app.NewWithTargets(profile.NewFileStore(filepath.Join(t.TempDir(), "profiles.json")), adapters)
	if err != nil {
		t.Fatal(err)
	}
	if result := application.Dispatch(app.Intent{Kind: app.RefreshTargets}); result.Err != nil {
		t.Fatal(result.Err)
	}

	snapshot := application.Snapshot()
	for _, index := range []int{0, 1} {
		action := snapshot.Targets[index].PrimaryAction
		if action.Available || !strings.Contains(action.DisabledReason, "no Active Profile") {
			t.Errorf("profile-dependent primary action = %#v", action)
		}
	}
	drift := snapshot.Targets[2]
	if !drift.PrimaryAction.Available {
		t.Fatalf("Restore Original should keep Resolve available: %#v", drift.PrimaryAction)
	}
	if got := drift.DriftResolutionActions[0]; got.Available || !strings.Contains(got.DisabledReason, "no Active Profile") {
		t.Fatalf("Reapply action without Active Profile = %#v", got)
	}
	if got := drift.DriftResolutionActions[1]; !got.Available {
		t.Fatalf("Restore Original action without Active Profile = %#v", got)
	}
}