package commandkit_test

import (
	"bytes"
	"context"
	"errors"
	"io"
	"strings"
	"testing"

	commandkit "gitea.maximumdirect.net/eric/CommandKit"
	configkit "gitea.maximumdirect.net/eric/ConfigKit"
)

func TestExecuteRunsTypedCommandsWithFreshInvocationState(t *testing.T) {
	type input struct {
		name commandkit.Supplied[string]
		ids  commandkit.Supplied[[]string]
	}
	var inputs []input
	var contexts []context.Context
	var streams []commandkit.Streams
	ctx := context.WithValue(context.Background(), struct{}{}, "invocation")
	var out, diagnostic bytes.Buffer
	command, err := commandkit.NewCommand(commandkit.CommandSpec[input]{
		Name: "run",
		Flags: []commandkit.Flag[input]{
			commandkit.ValueFlag(commandkit.FlagMeta{Name: "name"}, (*string)(nil), func(value string) (string, error) { return value, nil }, func(target *input, value commandkit.Supplied[string]) { target.name = value }),
			commandkit.RepeatFlag(commandkit.FlagMeta{Name: "id"}, nil, func(value string) (string, error) { return value, nil }, func(target *input, value commandkit.Supplied[[]string]) { target.ids = value }),
		},
		Run: func(invocation commandkit.Invocation, value input) commandkit.Outcome {
			inputs = append(inputs, value)
			contexts = append(contexts, invocation.Context)
			streams = append(streams, invocation.Streams)
			return commandkit.Success()
		},
	})
	if err != nil {
		t.Fatal(err)
	}
	app, err := commandkit.New(commandkit.Identity{Name: "example"}, command)
	if err != nil {
		t.Fatal(err)
	}
	first := app.Execute(ctx, []string{"run", "--name=first", "--id=a,b", "--id=c"}, commandkit.Streams{Out: &out, Err: &diagnostic})
	second := app.Execute(ctx, []string{"run"}, commandkit.Streams{Out: &out, Err: &diagnostic})
	third := app.Execute(ctx, []string{"run"}, commandkit.Streams{})
	if first.Kind != commandkit.OutcomeSuccess || second.Kind != commandkit.OutcomeSuccess || third.Kind != commandkit.OutcomeSuccess {
		t.Fatalf("outcomes = %#v, %#v, and %#v", first, second, third)
	}
	if len(inputs) != 3 || inputs[0].name.Value != "first" || !inputs[0].name.Set || len(inputs[0].ids.Value) != 2 || inputs[0].ids.Value[0] != "a,b" || inputs[0].ids.Value[1] != "c" {
		t.Fatalf("first input = %#v", inputs)
	}
	if inputs[1].name.Set || inputs[1].name.Value != "" || inputs[1].ids.Set {
		t.Fatalf("second invocation inherited state: %#v", inputs[1])
	}
	if streams[2].Out != io.Discard || streams[2].Err != io.Discard {
		t.Fatalf("nil streams were not replaced with io.Discard: %#v", streams[2])
	}
	if contexts[0] != ctx || streams[0].Out != &out || streams[0].Err != &diagnostic {
		t.Fatalf("handler invocation context or streams were not forwarded")
	}
}

func TestExecuteReturnsUsageForParsingRequirementsAndInputChecks(t *testing.T) {
	type input struct{ count commandkit.Supplied[int] }
	parseFailure := errors.New("bad count")
	checkFailure := errors.New("incompatible inputs")
	command, err := commandkit.NewCommand(commandkit.CommandSpec[input]{
		Name: "run",
		Flags: []commandkit.Flag[input]{commandkit.ValueFlag(commandkit.FlagMeta{Name: "count", Required: true}, nil, func(value string) (int, error) {
			if value == "bad" {
				return 0, parseFailure
			}
			return 0, nil
		}, func(target *input, value commandkit.Supplied[int]) { target.count = value })},
		Arguments:  []commandkit.Argument[input]{commandkit.ValueArgument(commandkit.ArgumentMeta{Name: "id"}, true, func(value string) (string, error) { return value, nil }, func(*input, commandkit.Supplied[string]) {})},
		CheckInput: func(input) error { return checkFailure },
		Run:        func(commandkit.Invocation, input) commandkit.Outcome { return commandkit.Success() },
	})
	if err != nil {
		t.Fatal(err)
	}
	app, err := commandkit.New(commandkit.Identity{Name: "example"}, command)
	if err != nil {
		t.Fatal(err)
	}
	var diagnostic bytes.Buffer
	missing := app.Execute(context.Background(), []string{"run"}, commandkit.Streams{Err: &diagnostic})
	if missing.Kind != commandkit.OutcomeUsage || missing.Status != 2 || !strings.Contains(diagnostic.String(), "Usage: example run") {
		t.Fatalf("missing required input = %#v, diagnostics %q", missing, diagnostic.String())
	}
	malformed := app.Execute(context.Background(), []string{"run", "--count=bad", "id"}, commandkit.Streams{Err: &diagnostic})
	if malformed.Kind != commandkit.OutcomeUsage || !errors.Is(malformed.Cause, parseFailure) {
		t.Fatalf("parser failure = %#v", malformed)
	}
	checked := app.Execute(context.Background(), []string{"run", "--count=1", "id"}, commandkit.Streams{Err: &diagnostic})
	if checked.Kind != commandkit.OutcomeUsage || !errors.Is(checked.Cause, checkFailure) {
		t.Fatalf("input check failure = %#v", checked)
	}
}

func TestExecutePreservesDomainOutcomesAndWarningDiagnostics(t *testing.T) {
	domainCause := errors.New("domain rejected the request")
	warning := commandkit.MessageDiagnostic(configkit.SeverityWarning, "review needed")
	command, err := commandkit.NewCommand(commandkit.CommandSpec[struct{}]{
		Name: "run",
		Run: func(commandkit.Invocation, struct{}) commandkit.Outcome {
			outcome := commandkit.Domain("sample", 2, domainCause)
			outcome.Diagnostics = []commandkit.Diagnostic{warning}
			return outcome
		},
	})
	if err != nil {
		t.Fatal(err)
	}
	app, err := commandkit.New(commandkit.Identity{Name: "example"}, command)
	if err != nil {
		t.Fatal(err)
	}
	var diagnostic bytes.Buffer
	outcome := app.Execute(context.Background(), []string{"run"}, commandkit.Streams{Err: &diagnostic})
	if outcome.Kind != commandkit.OutcomeDomain || outcome.Domain != "sample" || outcome.Status != 2 || !errors.Is(outcome.Cause, domainCause) {
		t.Fatalf("domain outcome changed: %#v", outcome)
	}
	if diagnostic.String() != "review needed\ndomain rejected the request\n" || outcome.DiagnosticDelivery != commandkit.DeliveryComplete {
		t.Fatalf("warning delivery = %q, %#v", diagnostic.String(), outcome)
	}
	warningOnly, err := commandkit.NewCommand(commandkit.CommandSpec[struct{}]{
		Name: "warn",
		Run: func(commandkit.Invocation, struct{}) commandkit.Outcome {
			result := commandkit.Success()
			result.Diagnostics = []commandkit.Diagnostic{warning}
			return result
		},
	})
	if err != nil {
		t.Fatal(err)
	}
	app, err = commandkit.New(commandkit.Identity{Name: "example"}, warningOnly)
	if err != nil {
		t.Fatal(err)
	}
	diagnostic.Reset()
	outcome = app.Execute(context.Background(), []string{"warn"}, commandkit.Streams{Err: &diagnostic})
	if outcome.Kind != commandkit.OutcomeSuccess || diagnostic.String() != "review needed\n" {
		t.Fatalf("warning-only outcome = %#v, diagnostics %q", outcome, diagnostic.String())
	}
}

func TestExecuteDoesNotRepeatCompletedDiagnosticsOrPresentedCauses(t *testing.T) {
	cause := errors.New("already shown")
	command, err := commandkit.NewCommand(commandkit.CommandSpec[struct{}]{
		Name: "run",
		Run: func(commandkit.Invocation, struct{}) commandkit.Outcome {
			outcome := commandkit.Domain("sample", 2, cause)
			outcome.Diagnostics = []commandkit.Diagnostic{{Severity: configkit.SeverityError, Write: func(writer io.Writer) error {
				_, err := io.WriteString(writer, "presented\n")
				return err
			}}}
			return outcome
		},
	})
	if err != nil {
		t.Fatal(err)
	}
	app, err := commandkit.New(commandkit.Identity{Name: "example"}, command)
	if err != nil {
		t.Fatal(err)
	}
	var diagnostic bytes.Buffer
	outcome := app.Execute(context.Background(), []string{"run"}, commandkit.Streams{Err: &diagnostic})
	if outcome.Kind != commandkit.OutcomeDomain || diagnostic.String() != "presented\n" {
		t.Fatalf("presented cause was duplicated: %#v, %q", outcome, diagnostic.String())
	}

	diagnostic.Reset()
	completed := commandkit.Domain("sample", 2, cause)
	completed.DiagnosticDelivery = commandkit.DeliveryComplete
	command, err = commandkit.NewCommand(commandkit.CommandSpec[struct{}]{Name: "done", Run: func(commandkit.Invocation, struct{}) commandkit.Outcome { return completed }})
	if err != nil {
		t.Fatal(err)
	}
	app, err = commandkit.New(commandkit.Identity{Name: "example"}, command)
	if err != nil {
		t.Fatal(err)
	}
	outcome = app.Execute(context.Background(), []string{"done"}, commandkit.Streams{Err: &diagnostic})
	if diagnostic.Len() != 0 || outcome.DiagnosticDelivery != commandkit.DeliveryComplete {
		t.Fatalf("completed diagnostics were repeated: %#v, %q", outcome, diagnostic.String())
	}
}

func TestExecuteRetainsOperationAndDiagnosticDeliveryFailures(t *testing.T) {
	operationFailure := context.Canceled
	writeFailure := errors.New("writer failed")
	command, err := commandkit.NewCommand(commandkit.CommandSpec[struct{}]{
		Name: "run",
		Run: func(commandkit.Invocation, struct{}) commandkit.Outcome {
			outcome := commandkit.Failure(operationFailure)
			outcome.ReportIncomplete = true
			return outcome
		},
	})
	if err != nil {
		t.Fatal(err)
	}
	app, err := commandkit.New(commandkit.Identity{Name: "example"}, command)
	if err != nil {
		t.Fatal(err)
	}
	outcome := app.Execute(context.Background(), []string{"run"}, commandkit.Streams{Err: failingWriter{err: writeFailure}})
	if outcome.Kind != commandkit.OutcomeOperational || outcome.Status != 1 || outcome.DiagnosticDelivery != commandkit.DeliveryIncomplete || !outcome.ReportIncomplete || !errors.Is(outcome.Cause, operationFailure) || !errors.Is(outcome.DeliveryError, writeFailure) {
		t.Fatalf("combined operation and delivery failure = %#v", outcome)
	}

	short := app.Execute(context.Background(), []string{"run"}, commandkit.Streams{Err: shortWriter{}})
	if !errors.Is(short.DeliveryError, io.ErrShortWrite) || short.DiagnosticDelivery != commandkit.DeliveryIncomplete {
		t.Fatalf("short write was not detected: %#v", short)
	}
}

func TestExecuteHelpSkipsRequiredInputsAndRejectsNilContext(t *testing.T) {
	type input struct{ id commandkit.Supplied[string] }
	factoryCalls, checkCalls, runCalls := 0, 0, 0
	command, err := commandkit.NewCommand(commandkit.CommandSpec[input]{
		Name: "run",
		NewInput: func() input {
			factoryCalls++
			return input{}
		},
		Arguments:  []commandkit.Argument[input]{commandkit.ValueArgument(commandkit.ArgumentMeta{Name: "id"}, true, func(value string) (string, error) { return value, nil }, func(target *input, value commandkit.Supplied[string]) { target.id = value })},
		CheckInput: func(input) error { checkCalls++; return nil },
		Run:        func(commandkit.Invocation, input) commandkit.Outcome { runCalls++; return commandkit.Success() },
	})
	if err != nil {
		t.Fatal(err)
	}
	app, err := commandkit.New(commandkit.Identity{Name: "example"}, command)
	if err != nil {
		t.Fatal(err)
	}
	help := app.Execute(context.Background(), []string{"run", "--help"}, commandkit.Streams{})
	if help.Kind != commandkit.OutcomeSuccess || factoryCalls != 0 || checkCalls != 0 || runCalls != 0 {
		t.Fatalf("help request invoked execution path: %#v calls=%d/%d/%d", help, factoryCalls, checkCalls, runCalls)
	}
	invalid := app.Execute(nil, []string{"run"}, commandkit.Streams{})
	if invalid.Kind != commandkit.OutcomeOperational || invalid.Status != 1 || invalid.Cause == nil {
		t.Fatalf("nil context outcome = %#v", invalid)
	}
}

type failingWriter struct{ err error }

func (w failingWriter) Write([]byte) (int, error) { return 0, w.err }

type shortWriter struct{}

func (shortWriter) Write(data []byte) (int, error) {
	if len(data) == 0 {
		return 0, nil
	}
	return len(data) - 1, nil
}