package yaml

import (
	"bytes"
	"errors"
	"io"
	"testing"

	"gitea.maximumdirect.net/eric/ConfigKit/internal/document"
)

func TestWriteUsesStableExplicitFormatting(t *testing.T) {
	t.Parallel()
	root := &document.Node{Kind: document.Mapping, Mapping: []document.Entry{
		{Key: "empty_map", Value: &document.Node{Kind: document.Mapping, Mapping: []document.Entry{}}},
		{Key: "empty_sequence", Value: &document.Node{Kind: document.Sequence, Sequence: []*document.Node{}}},
		{Key: "number", Value: &document.Node{Kind: document.Number, Text: "1.25e+2"}},
		{Key: "redacted", Value: &document.Node{Kind: document.String, Text: "[REDACTED]"}},
		{Key: "sequence", Value: &document.Node{Kind: document.Sequence, Sequence: []*document.Node{
			{Kind: document.String, Text: "first"},
			{Kind: document.String, Text: "true"},
		}}},
		{Key: "nil_value", Value: &document.Node{Kind: document.Null}},
	}}
	var output bytes.Buffer
	if err := Write(&output, root); err != nil {
		t.Fatal(err)
	}
	want := "empty_map: {}\nempty_sequence: []\nnumber: 1.25e+2\nredacted: '[REDACTED]'\nsequence:\n  - first\n  - 'true'\nnil_value: null\n"
	if output.String() != want {
		t.Fatalf("output:\n%s\nwant:\n%s", output.String(), want)
	}
}

func TestWritePropagatesWriterErrorsAndShortWrites(t *testing.T) {
	t.Parallel()
	root := &document.Node{Kind: document.Mapping, Mapping: []document.Entry{{Key: "value", Value: &document.Node{Kind: document.String, Text: "safe"}}}}
	want := errors.New("write failed")
	if err := Write(failingWriter{err: want}, root); !errors.Is(err, want) {
		t.Fatalf("writer error = %v", err)
	}
	if err := Write(shortOutput{}, root); !errors.Is(err, io.ErrShortWrite) {
		t.Fatalf("short writer error = %v", err)
	}
}

type failingWriter struct {
	err error
}

func (writer failingWriter) Write(data []byte) (int, error) {
	return min(2, len(data)), writer.err
}

type shortOutput struct{}

func (shortOutput) Write(data []byte) (int, error) {
	return max(0, len(data)-1), nil
}