package ckconfig

import (
	"context"
	"io"
	"strings"
	"testing"

	commandkit "gitea.maximumdirect.net/eric/CommandKit"
	configkit "gitea.maximumdirect.net/eric/ConfigKit"
)

func TestComparisonSelectionInheritsFieldsIndependently(t *testing.T) {
	leftConfig := commandkit.Supplied[string]{Value: "before.yml", Set: true}
	leftOverlay := commandkit.Supplied[string]{Value: "base", Set: true}
	tests := []struct {
		name  string
		left  Selection
		right Selection
		want  Selection
	}{
		{
			name: "omitted fields stay omitted",
		},
		{
			name: "both fields inherit supplied state",
			left: Selection{Config: leftConfig, Overlay: leftOverlay},
			want: Selection{Config: leftConfig, Overlay: leftOverlay},
		},
		{
			name:  "explicit empty config overrides while overlay inherits",
			left:  Selection{Config: leftConfig, Overlay: leftOverlay},
			right: Selection{Config: commandkit.Supplied[string]{Set: true}},
			want:  Selection{Config: commandkit.Supplied[string]{Set: true}, Overlay: leftOverlay},
		},
		{
			name:  "explicit overlay overrides while config inherits",
			left:  Selection{Config: leftConfig, Overlay: leftOverlay},
			right: Selection{Overlay: commandkit.Supplied[string]{Value: "candidate", Set: true}},
			want:  Selection{Config: leftConfig, Overlay: commandkit.Supplied[string]{Value: "candidate", Set: true}},
		},
		{
			name:  "explicit empty overlay remains supplied",
			left:  Selection{Config: leftConfig, Overlay: leftOverlay},
			right: Selection{Overlay: commandkit.Supplied[string]{Set: true}},
			want:  Selection{Config: leftConfig, Overlay: commandkit.Supplied[string]{Set: true}},
		},
		{
			name:  "both explicit right fields replace left",
			left:  Selection{Config: leftConfig, Overlay: leftOverlay},
			right: Selection{Config: commandkit.Supplied[string]{Value: "after.yml", Set: true}, Overlay: commandkit.Supplied[string]{Value: "new", Set: true}},
			want:  Selection{Config: commandkit.Supplied[string]{Value: "after.yml", Set: true}, Overlay: commandkit.Supplied[string]{Value: "new", Set: true}},
		},
	}
	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			if got := inheritComparisonSelection(test.left, test.right); got != test.want {
				t.Fatalf("inherited selection = %#v, want %#v", got, test.want)
			}
		})
	}
}

func TestComparisonHelpLimitsFlagsAndDefaultsFormatToYAML(t *testing.T) {
	scope := Scope[struct{}, struct{}]{
		Name: "app", Operations: []Operation{Diff, Show, Explain, Validate, Sources},
		Acquire: func(context.Context, Request, struct{}, struct{}) (commandkit.Acquired[View], error) {
			return commandkit.Acquired[View]{}, nil
		},
		Compare: func(context.Context, ComparisonRequest[struct{}], struct{}) (commandkit.Acquired[[]configkit.Difference], error) {
			return commandkit.Acquired[[]configkit.Difference]{}, nil
		},
	}
	app := newConfigTestApp(t, Command(Suite[struct{}, struct{}]{Scopes: []Scope[struct{}, struct{}]{scope}}))
	help := func(args ...string) string {
		t.Helper()
		var output strings.Builder
		app.Execute(context.Background(), args, commandkit.Streams{Out: &output, Err: io.Discard})
		return output.String()
	}

	diffHelp := help("config", "diff", "--help")
	if !strings.Contains(diffHelp, "--against-config") || !strings.Contains(diffHelp, "--against-overlay") {
		t.Fatalf("diff help omits right-side selection flags:\n%s", diffHelp)
	}
	if !strings.Contains(diffHelp, "default: yaml") {
		t.Fatalf("diff help does not show the YAML default:\n%s", diffHelp)
	}
	for _, operation := range []string{"validate", "show", "sources", "explain"} {
		operationHelp := help("config", operation, "--help")
		if strings.Contains(operationHelp, "--against-config") || strings.Contains(operationHelp, "--against-overlay") {
			t.Errorf("%s exposes comparison-only flags:\n%s", operation, operationHelp)
		}
		if operation == "show" && !strings.Contains(operationHelp, "default: yaml") {
			t.Errorf("show format default changed:\n%s", operationHelp)
		}
		if operation != "show" && !strings.Contains(operationHelp, "default: text") {
			t.Errorf("%s format default changed:\n%s", operation, operationHelp)
		}
		if operation != "explain" && strings.Contains(operationHelp, "--path") {
			t.Errorf("%s exposes the explain-only path flag:\n%s", operation, operationHelp)
		}
	}
	explainHelp := help("config", "explain", "--help")
	if !strings.Contains(explainHelp, "--path") {
		t.Fatalf("explain flags changed:\n%s", explainHelp)
	}
}

func TestComparisonPreparationAcceptsOnlyYAML(t *testing.T) {
	inputCalls, stateCalls := 0, 0
	prepared := captureSuite(Suite[struct{}, struct{}]{
		NewInput: func() struct{} { inputCalls++; return struct{}{} },
		NewState: func() struct{} { stateCalls++; return struct{}{} },
		Scopes: []Scope[struct{}, struct{}]{{
			Name: "app", Operations: []Operation{Diff},
			Compare: func(context.Context, ComparisonRequest[struct{}], struct{}) (commandkit.Acquired[[]configkit.Difference], error) {
				return commandkit.Acquired[[]configkit.Difference]{}, nil
			},
		}},
	})

	input := &configCommandInput[struct{}, struct{}]{
		selection: Selection{Config: commandkit.Supplied[string]{Value: "before.yml", Set: true}},
		against:   Selection{Overlay: commandkit.Supplied[string]{Value: "candidate", Set: true}},
		format:    commandkit.Supplied[string]{Value: "yaml", Set: true},
	}
	if err := prepareConfigOperation(prepared, Diff, input); err != nil {
		t.Fatalf("explicit YAML format rejected: %v", err)
	}
	if input.plan == nil || input.plan.format != "yaml" {
		t.Fatalf("comparison plan = %#v", input.plan)
	}
	if input.plan.scopeName != "app" {
		t.Fatalf("comparison default scope = %q, want app", input.plan.scopeName)
	}
	if want := (Selection{
		Config:  commandkit.Supplied[string]{Value: "before.yml", Set: true},
		Overlay: commandkit.Supplied[string]{Value: "candidate", Set: true},
	}); input.against != want {
		t.Fatalf("resolved right selection = %#v, want %#v", input.against, want)
	}

	for _, format := range []string{"text", "json"} {
		input := &configCommandInput[struct{}, struct{}]{format: commandkit.Supplied[string]{Value: format}}
		if err := prepareConfigOperation(prepared, Diff, input); err == nil {
			t.Errorf("comparison format %q was accepted", format)
		}
	}
	if inputCalls != 2 || stateCalls != 0 {
		t.Fatalf("comparison preparation calls input/state: %d/%d", inputCalls, stateCalls)
	}
}

func TestComparisonAvailabilityPreflightPrecedesFactories(t *testing.T) {
	inputCalls, stateCalls, acquireCalls, compareCalls := 0, 0, 0, 0
	prepared := captureSuite(Suite[struct{}, struct{}]{
		NewInput: func() struct{} { inputCalls++; return struct{}{} },
		NewState: func() struct{} { stateCalls++; return struct{}{} },
		Scopes: []Scope[struct{}, struct{}]{
			{Name: "app", Operations: []Operation{Diff}, Compare: func(context.Context, ComparisonRequest[struct{}], struct{}) (commandkit.Acquired[[]configkit.Difference], error) {
				compareCalls++
				return commandkit.Acquired[[]configkit.Difference]{}, nil
			}},
			{Name: "plain", Operations: []Operation{Validate}, Acquire: func(context.Context, Request, struct{}, struct{}) (commandkit.Acquired[View], error) {
				acquireCalls++
				return commandkit.Acquired[View]{}, nil
			}},
		},
	})
	for _, scope := range []string{"missing", "all", "plain"} {
		input := &configCommandInput[struct{}, struct{}]{
			scope:  commandkit.Supplied[string]{Value: scope, Set: true},
			format: commandkit.Supplied[string]{Value: "yaml"},
		}
		if err := prepareConfigOperation(prepared, Diff, input); err == nil {
			t.Errorf("comparison scope %q was accepted", scope)
		}
	}
	if inputCalls != 0 || stateCalls != 0 || acquireCalls != 0 || compareCalls != 0 {
		t.Fatalf("failed preflight invoked suite work: input=%d state=%d acquire=%d compare=%d", inputCalls, stateCalls, acquireCalls, compareCalls)
	}
}