package tui

import (
	"testing"
)

func TestDiscoverSlots(t *testing.T) {
	tests := []struct {
		name      string
		body      string
		wantNames []string
	}{
		{"no slots", "plain text", nil},
		{"single slot", "Hello ${name}", []string{"name"}},
		{"multiple slots", "${greeting} ${name}, welcome to ${place}", []string{"greeting", "name", "place"}},
		{"duplicate slot deduped", "${x} and ${x} again", []string{"x"}},
		{"adjacent slots", "${a}${b}", []string{"a", "b"}},
		{"nested braces ignored", "${{bad}}", nil},
		{"empty body", "", nil},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			got := discoverSlots(tt.body)
			if len(tt.wantNames) == 0 && len(got) == 0 {
				return
			}
			if len(got) != len(tt.wantNames) {
				t.Fatalf("got %d slots, want %d", len(got), len(tt.wantNames))
			}
			for i, s := range got {
				if s.Name != tt.wantNames[i] {
					t.Fatalf("slot[%d].Name = %q, want %q", i, s.Name, tt.wantNames[i])
				}
			}
		})
	}
}

func TestResolve(t *testing.T) {
	tests := []struct {
		name  string
		body  string
		slots []fillSlot
		want  string
	}{
		{
			"all filled",
			"Hello ${name}, welcome to ${place}",
			[]fillSlot{{Name: "name", Value: "Alice"}, {Name: "place", Value: "Nib"}},
			"Hello Alice, welcome to Nib",
		},
		{
			"unfilled stays as placeholder",
			"${greeting} ${name}",
			[]fillSlot{{Name: "greeting", Value: "Hi"}, {Name: "name"}},
			"Hi ${name}",
		},
		{
			"no slots",
			"plain text",
			nil,
			"plain text",
		},
		{
			"repeated slot filled everywhere",
			"${x} and ${x}",
			[]fillSlot{{Name: "x", Value: "Y"}},
			"Y and Y",
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			f := fillModel{body: tt.body, slots: tt.slots}
			if got := f.resolve(); got != tt.want {
				t.Fatalf("resolve() = %q, want %q", got, tt.want)
			}
		})
	}
}