package commandkit

import (
	"cmp"
	"reflect"
	"slices"
	"testing"

	commandmeta "gitea.maximumdirect.net/eric/CommandKit/internal/commandmeta"
)

func TestCompletionCommandContext(t *testing.T) {
	parse := func(value string) (string, error) { return value, nil }
	mixed := NewCommand(CommandSpec[struct{}]{
		Name: "mixed", Children: []Command{simpleRunnable("child")},
		Arguments: []Argument[struct{}]{ValueArgument(ArgumentMeta{Name: "item"}, false, parse, func(*struct{}, Supplied[string]) {})},
		Run:       func(Invocation, struct{}) Outcome { return Success() },
	})
	app, err := New(Identity{Name: "example"},
		Group("workspace", "", Group("list", "", simpleRunnable("shadow"), simpleRunnable("show"))),
		simpleRunnable("other"), mixed, Completion("example"),
		Alias("ws", "workspace"), Alias("w", "ws"), Alias("ws list shadow", "other"),
		Alias("legacy inspect", "workspace list"), FlagAlias("--silent", "--quiet"),
		FlagAliasFor("workspace list", "--detail", "--verbose"),
	)
	if err != nil {
		t.Fatal(err)
	}
	snapshot := app.routeSnapshot()
	for _, tc := range []struct {
		name      string
		completed []string
		current   string
		path      string
		position  bool
		choices   []string
		kind      routeKind
	}{
		{"root", nil, "work", "", true, []string{"workspace"}, routeCanonical},
		{"group", []string{"workspace"}, "li", "workspace", true, []string{"list"}, routeCanonical},
		{"entered alias", []string{"ws", "list"}, "sh", "workspace list", true, []string{"show"}, routeCanonical},
		{"alias chain", []string{"w", "list"}, "sh", "workspace list", true, []string{"show"}, routeCanonical},
		{"discovery", []string{"legacy"}, "in", "", false, nil, routeDiscovery},
		{"complete alias", []string{"legacy", "inspect"}, "sh", "workspace list", true, []string{"shadow", "show"}, routeCanonical},
		{"runnable child", []string{"mixed"}, "ch", "mixed", true, []string{"child"}, routeCanonical},
		{"unmatched child", []string{"mixed"}, "other", "mixed", true, nil, routeCanonical},
		{"runnable operand", []string{"mixed", "value"}, "ch", "mixed", false, nil, routeCanonical},
		{"flag ends path", []string{"mixed", "--quiet"}, "ch", "mixed", false, nil, routeCanonical},
		{"flag before child", []string{"workspace", "--quiet"}, "li", "workspace", false, nil, routeCanonical},
		{"unknown", []string{"missing"}, "x", "", false, nil, routeUnknown},
		{"hidden endpoint", nil, "__comp", "", true, nil, routeCanonical},
	} {
		t.Run(tc.name, func(t *testing.T) {
			original := append([]string(nil), tc.completed...)
			context := resolveCompletionContext(snapshot, tc.completed, tc.current)
			if context.route.kind != tc.kind || context.route.canonicalPath.String() != tc.path || context.commandPosition != tc.position || !reflect.DeepEqual(tc.completed, original) {
				t.Fatalf("context=%#v completed=%q", context, tc.completed)
			}
			var names []string
			for _, choice := range completionChildren(snapshot, context) {
				names = append(names, choice.Value)
			}
			if !reflect.DeepEqual(names, tc.choices) {
				t.Fatalf("children=%q, want %q", names, tc.choices)
			}
			if tc.kind == routeDiscovery && !reflect.DeepEqual(context.aliases, []commandmeta.FlagAlias{{Source: "--silent", Target: "--quiet"}}) {
				t.Fatalf("discovery aliases=%#v", context.aliases)
			}
			if (tc.name == "runnable child" || tc.name == "unmatched child") && (context.command == nil || len(context.command.Arguments) != 1) {
				t.Fatalf("runnable operand metadata missing: %#v", context.command)
			}
			if tc.name == "entered alias" {
				actual := slices.Clone(context.aliases)
				expected := []commandmeta.FlagAlias{{Source: "--detail", Target: "--verbose"}, {Source: "--silent", Target: "--quiet"}}
				compare := func(a, b commandmeta.FlagAlias) int {
					if result := cmp.Compare(a.Source, b.Source); result != 0 {
						return result
					}
					return cmp.Compare(a.Target, b.Target)
				}
				slices.SortFunc(actual, compare)
				slices.SortFunc(expected, compare)
				if !slices.Equal(actual, expected) {
					t.Fatalf("canonical aliases=%#v, want %#v", actual, expected)
				}
			}
		})
	}
}