package commandkit

import (
	"errors"
	"fmt"
	"io"
	"testing"
)

func TestReporterPreservesJoinedRendererEvidence(t *testing.T) {
	for _, kind := range []string{"output", "detail"} {
		for _, test := range []struct {
			name      string
			combine   func(error, error) error
			rendering bool
		}{
			{"joined", func(render, write error) error { return errors.Join(render, write) }, true},
			{"wrapped join", func(render, write error) error {
				return fmt.Errorf("rendering context: %w", errors.Join(write, render))
			}, true},
			{"plain write", func(_, write error) error { return write }, false},
			{"wrapped write", func(_, write error) error { return fmt.Errorf("writing context: %w", write) }, false},
			{"joined write only", func(_, write error) error { return errors.Join(write, fmt.Errorf("same writer: %w", write)) }, false},
		} {
			t.Run(kind+"/"+test.name, func(t *testing.T) {
				renderErr := errors.New("independent rendering failure")
				// The destination error can itself be a joined value. Returning that
				// complete error still propagates a single destination failure.
				writeErr := errors.Join(errors.New("sink failure"), errors.New("sink detail"))
				destination := &reporterTestWriter{err: writeErr}
				reporter := newReporter(Streams{Out: destination, Err: destination})
				reporter.setVisibility(modeVerbose, false, false)
				render := func(w io.Writer) error {
					_, err := io.WriteString(w, "report")
					return test.combine(renderErr, err)
				}
				var err error
				if kind == "output" {
					err = reporter.RenderOutput(render)
				} else {
					err = reporter.Warn("", render)
				}
				if !errors.Is(err, writeErr) || errors.Is(err, renderErr) != test.rendering {
					t.Fatalf("returned error lost evidence: %v", err)
				}
				got := reporter.finalize(Success(), nil)
				result := got.Presentation.Output
				if kind == "detail" {
					result = got.Presentation.Diagnostics
				}
				if result.State != DeliveryIncomplete || !errors.Is(result.WriteError, writeErr) || errors.Is(result.RenderError, renderErr) != test.rendering {
					t.Fatalf("presentation=%#v", result)
				}
				if !test.rendering && result.RenderError != nil {
					t.Fatalf("write propagation became rendering evidence: %v", result.RenderError)
				}
			})
		}
	}
}