package commandkit

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

func TestReporterExplainsItsOwnFailuresWithoutExposingCauses(t *testing.T) {
	for _, kind := range []string{"output", "diagnostics"} {
		for _, quiet := range []bool{false, true} {
			t.Run(fmt.Sprintf("%s/quiet=%t", kind, quiet), func(t *testing.T) {
				var diagnostics bytes.Buffer
				reporter := newReporter(Streams{Err: &diagnostics})
				if quiet {
					reporter.setVisibility(modeQuiet, false, false)
				}
				failure := errors.New("private rendering detail")
				render := func(io.Writer) error { return failure }
				if kind == "output" {
					_ = reporter.RenderOutput(render)
				} else {
					_ = reporter.Warn("", render)
				}
				cause := errors.New("private application cause")
				got := reporter.finalize(Domain("example", 0).WithCause(cause), nil)
				if got.Kind != OutcomeDomain || got.Status != 1 || got.Cause != cause {
					t.Fatalf("outcome=%#v", got)
				}
				if !strings.Contains(got.Explanation.Message, "render") || !strings.Contains(got.Explanation.Message, kind) || !strings.Contains(diagnostics.String(), got.Explanation.Message) {
					t.Fatalf("explanation=%#v diagnostics=%q", got.Explanation, diagnostics.String())
				}
				if strings.Contains(diagnostics.String(), "private") {
					t.Fatalf("private error text was exposed: %q", diagnostics.String())
				}
			})
		}
	}
}

func TestReporterPreservesExplicitSuccessExplanationOnPresentationFailure(t *testing.T) {
	for _, message := range []string{"supplied context", ""} {
		t.Run(message, func(t *testing.T) {
			var diagnostics bytes.Buffer
			reporter := newReporter(Streams{Err: &diagnostics})
			_ = reporter.RenderOutput(func(io.Writer) error { return errors.New("render failed") })
			calls := 0
			got := reporter.finalize(Success().WithExplanation(message, func(io.Writer) error {
				calls++
				return nil
			}), nil)
			if got.Status != 1 || got.Explanation.Message != message || calls != 1 {
				t.Fatalf("outcome=%#v calls=%d", got, calls)
			}
			if message == "" && diagnostics.Len() != 0 {
				t.Fatalf("explicit zero-byte explanation replaced: %q", diagnostics.String())
			}
		})
	}
}

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)
				}
			})
		}
	}
}