package config

import (
	"os"
	"path/filepath"
	"strings"
	"testing"
)

func TestLoadersRejectTrailingYAMLDocuments(t *testing.T) {
	dir := t.TempDir()
	pipelinePath := filepath.Join(dir, "pipeline.yml")
	campaignPath := filepath.Join(dir, "campaign.yml")
	if err := os.WriteFile(pipelinePath, []byte("workspace:\n  root: /tmp/narratio\n---\nworkspace:\n  root: /other\n"), 0o644); err != nil {
		t.Fatalf("write pipeline.yml: %v", err)
	}
	if err := os.WriteFile(campaignPath, []byte("campaign_id: sample-campaign\n---\nnull\n"), 0o644); err != nil {
		t.Fatalf("write campaign.yml: %v", err)
	}

	tests := []struct {
		name string
		load func() error
	}{
		{
			name: "pipeline",
			load: func() error {
				_, err := LoadPipeline(pipelinePath)
				return err
			},
		},
		{
			name: "campaign",
			load: func() error {
				_, err := LoadCampaign(campaignPath)
				return err
			},
		},
		{
			name: "remote session bytes",
			load: func() error {
				_, err := LoadSessionBytesWithOptions("s3://bucket/session.yml", []byte("session_id: 2026-05-03\n---\n# another document\nnull\n"), SessionLoadOptions{})
				return err
			},
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			err := tt.load()
			if err == nil || (!strings.Contains(err.Error(), "exactly one YAML document") && !strings.Contains(err.Error(), "yaml.multiple_documents")) {
				t.Fatalf("load error = %v, want exactly-one-document error", err)
			}
		})
	}
}