package behavior

import (
	"strings"
	"testing"

	"gopkg.in/yaml.v3"
)

func TestDescListScalarForm(t *testing.T) {
	var wrap struct {
		Description DescList `yaml:"description"`
	}
	if err := yaml.Unmarshal([]byte("description: \"A dark room.\"\n"), &wrap); err != nil {
		t.Fatalf("scalar description failed to decode: %v", err)
	}
	if len(wrap.Description) != 1 || wrap.Description[0].Text != "A dark room." {
		t.Fatalf("scalar decode = %#v", wrap.Description)
	}
}

func TestDescListSequenceForm(t *testing.T) {
	src := "description:\n  - text: \"Default\"\n  - text: \"Lit\"\n    condition:\n      player_flag: lamp_lit\n"
	var wrap struct {
		Description DescList `yaml:"description"`
	}
	if err := yaml.Unmarshal([]byte(src), &wrap); err != nil {
		t.Fatalf("sequence description failed to decode: %v", err)
	}
	if len(wrap.Description) != 2 {
		t.Fatalf("got %d variants, want 2", len(wrap.Description))
	}
	if wrap.Description[1].Condition == nil {
		t.Fatal("conditional variant lost its condition")
	}
}

func TestDescListRoundTripPreservesCondition(t *testing.T) {
	original := DescList{
		{Text: "Default"},
		{Text: "Lit", Condition: &Condition{PlayerFlag: "lamp_lit"}},
	}
	data, err := yaml.Marshal(struct {
		Description DescList `yaml:"description"`
	}{Description: original})
	if err != nil {
		t.Fatalf("marshal: %v", err)
	}
	// A conditional list must not collapse to the scalar shorthand.
	if strings.Contains(string(data), "description: Default") {
		t.Fatalf("conditional list collapsed to scalar:\n%s", data)
	}
	var loaded struct {
		Description DescList `yaml:"description"`
	}
	if err := yaml.Unmarshal(data, &loaded); err != nil {
		t.Fatalf("unmarshal: %v", err)
	}
	if len(loaded.Description) != 2 || loaded.Description[1].Condition == nil {
		t.Fatalf("round trip lost structure: %#v", loaded.Description)
	}
}

func TestDescListSingleVariantMarshalsAsScalar(t *testing.T) {
	data, err := yaml.Marshal(struct {
		Description DescList `yaml:"description"`
	}{Description: DescList{{Text: "A dark room."}}})
	if err != nil {
		t.Fatalf("marshal: %v", err)
	}
	if !strings.Contains(string(data), "description: A dark room.") {
		t.Fatalf("single unconditional variant should use the scalar form:\n%s", data)
	}
}

func TestDescListEmptyStillMarshals(t *testing.T) {
	data, err := yaml.Marshal(struct {
		Description DescList `yaml:"description"`
	}{})
	if err != nil {
		t.Fatalf("marshal empty: %v", err)
	}
	if !strings.Contains(string(data), "description:") {
		t.Fatalf("empty description should still emit a key:\n%s", data)
	}
}