package cobra

import (
	"bytes"
	"strings"
	"testing"
)

func validArgsFunc(cmd *Command, args []string, toComplete string) ([]string, BashCompDirective) {
	if len(args) != 0 {
		return nil, BashCompDirectiveNoFileComp
	}

	var completions []string
	for _, comp := range []string{"one", "two"} {
		if strings.HasPrefix(comp, toComplete) {
			completions = append(completions, comp)
		}
	}
	return completions, BashCompDirectiveDefault
}

func validArgsFunc2(cmd *Command, args []string, toComplete string) ([]string, BashCompDirective) {
	if len(args) != 0 {
		return nil, BashCompDirectiveNoFileComp
	}

	var completions []string
	for _, comp := range []string{"three", "four"} {
		if strings.HasPrefix(comp, toComplete) {
			completions = append(completions, comp)
		}
	}
	return completions, BashCompDirectiveDefault
}

func TestValidArgsFuncSingleCmd(t *testing.T) {
	rootCmd := &Command{
		Use:               "root",
		ValidArgsFunction: validArgsFunc,
		Run:               emptyRun,
	}

	// Test completing an empty string
	output, err := executeCommand(rootCmd, CompRequestCmd, "")
	if err != nil {
		t.Errorf("Unexpected error: %v", err)
	}

	expected := strings.Join([]string{
		"one",
		"two",
		":0",
		"Completion ended with directive: BashCompDirectiveDefault", ""}, "\n")

	if output != expected {
		t.Errorf("expected: %q, got: %q", expected, output)
	}

	// Check completing with a prefix
	output, err = executeCommand(rootCmd, CompRequestCmd, "t")
	if err != nil {
		t.Errorf("Unexpected error: %v", err)
	}

	expected = strings.Join([]string{
		"two",
		":0",
		"Completion ended with directive: BashCompDirectiveDefault", ""}, "\n")

	if output != expected {
		t.Errorf("expected: %q, got: %q", expected, output)
	}
}

func TestValidArgsFuncSingleCmdInvalidArg(t *testing.T) {
	rootCmd := &Command{
		Use: "root",
		// If we don't specify a value for Args, this test fails.
		// This is only true for a root command without any subcommands, and is caused
		// by the fact that the __complete command becomes a subcommand when there should not be one.
		// The problem is in the implementation of legacyArgs().
		Args:              MinimumNArgs(1),
		ValidArgsFunction: validArgsFunc,
		Run:               emptyRun,
	}

	// Check completing with wrong number of args
	output, err := executeCommand(rootCmd, CompRequestCmd, "unexpectedArg", "t")
	if err != nil {
		t.Errorf("Unexpected error: %v", err)
	}

	expected := strings.Join([]string{
		":4",
		"Completion ended with directive: BashCompDirectiveNoFileComp", ""}, "\n")

	if output != expected {
		t.Errorf("expected: %q, got: %q", expected, output)
	}
}

func TestValidArgsFuncChildCmds(t *testing.T) {
	rootCmd := &Command{Use: "root", Args: NoArgs, Run: emptyRun}
	child1Cmd := &Command{
		Use:               "child1",
		ValidArgsFunction: validArgsFunc,
		Run:               emptyRun,
	}
	child2Cmd := &Command{
		Use:               "child2",
		ValidArgsFunction: validArgsFunc2,
		Run:               emptyRun,
	}
	rootCmd.AddCommand(child1Cmd, child2Cmd)

	// Test completion of first sub-command with empty argument
	output, err := executeCommand(rootCmd, CompRequestCmd, "child1", "")
	if err != nil {
		t.Errorf("Unexpected error: %v", err)
	}

	expected := strings.Join([]string{
		"one",
		"two",
		":0",
		"Completion ended with directive: BashCompDirectiveDefault", ""}, "\n")

	if output != expected {
		t.Errorf("expected: %q, got: %q", expected, output)
	}

	// Test completion of first sub-command with a prefix to complete
	output, err = executeCommand(rootCmd, CompRequestCmd, "child1", "t")
	if err != nil {
		t.Errorf("Unexpected error: %v", err)
	}

	expected = strings.Join([]string{
		"two",
		":0",
		"Completion ended with directive: BashCompDirectiveDefault", ""}, "\n")

	if output != expected {
		t.Errorf("expected: %q, got: %q", expected, output)
	}

	// Check completing with wrong number of args
	output, err = executeCommand(rootCmd, CompRequestCmd, "child1", "unexpectedArg", "t")
	if err != nil {
		t.Errorf("Unexpected error: %v", err)
	}

	expected = strings.Join([]string{
		":4",
		"Completion ended with directive: BashCompDirectiveNoFileComp", ""}, "\n")

	if output != expected {
		t.Errorf("expected: %q, got: %q", expected, output)
	}

	// Test completion of second sub-command with empty argument
	output, err = executeCommand(rootCmd, CompRequestCmd, "child2", "")
	if err != nil {
		t.Errorf("Unexpected error: %v", err)
	}

	expected = strings.Join([]string{
		"three",
		"four",
		":0",
		"Completion ended with directive: BashCompDirectiveDefault", ""}, "\n")

	if output != expected {
		t.Errorf("expected: %q, got: %q", expected, output)
	}

	output, err = executeCommand(rootCmd, CompRequestCmd, "child2", "t")
	if err != nil {
		t.Errorf("Unexpected error: %v", err)
	}

	expected = strings.Join([]string{
		"three",
		":0",
		"Completion ended with directive: BashCompDirectiveDefault", ""}, "\n")

	if output != expected {
		t.Errorf("expected: %q, got: %q", expected, output)
	}

	// Check completing with wrong number of args
	output, err = executeCommand(rootCmd, CompRequestCmd, "child2", "unexpectedArg", "t")
	if err != nil {
		t.Errorf("Unexpected error: %v", err)
	}

	expected = strings.Join([]string{
		":4",
		"Completion ended with directive: BashCompDirectiveNoFileComp", ""}, "\n")

	if output != expected {
		t.Errorf("expected: %q, got: %q", expected, output)
	}
}

func TestValidArgsFuncAliases(t *testing.T) {
	rootCmd := &Command{Use: "root", Args: NoArgs, Run: emptyRun}
	child := &Command{
		Use:               "child",
		Aliases:           []string{"son", "daughter"},
		ValidArgsFunction: validArgsFunc,
		Run:               emptyRun,
	}
	rootCmd.AddCommand(child)

	// Test completion of first sub-command with empty argument
	output, err := executeCommand(rootCmd, CompRequestCmd, "son", "")
	if err != nil {
		t.Errorf("Unexpected error: %v", err)
	}

	expected := strings.Join([]string{
		"one",
		"two",
		":0",
		"Completion ended with directive: BashCompDirectiveDefault", ""}, "\n")

	if output != expected {
		t.Errorf("expected: %q, got: %q", expected, output)
	}

	// Test completion of first sub-command with a prefix to complete
	output, err = executeCommand(rootCmd, CompRequestCmd, "daughter", "t")
	if err != nil {
		t.Errorf("Unexpected error: %v", err)
	}

	expected = strings.Join([]string{
		"two",
		":0",
		"Completion ended with directive: BashCompDirectiveDefault", ""}, "\n")

	if output != expected {
		t.Errorf("expected: %q, got: %q", expected, output)
	}

	// Check completing with wrong number of args
	output, err = executeCommand(rootCmd, CompRequestCmd, "son", "unexpectedArg", "t")
	if err != nil {
		t.Errorf("Unexpected error: %v", err)
	}

	expected = strings.Join([]string{
		":4",
		"Completion ended with directive: BashCompDirectiveNoFileComp", ""}, "\n")

	if output != expected {
		t.Errorf("expected: %q, got: %q", expected, output)
	}
}

func TestValidArgsFuncInScript(t *testing.T) {
	rootCmd := &Command{Use: "root", Args: NoArgs, Run: emptyRun}
	child := &Command{
		Use:               "child",
		ValidArgsFunction: validArgsFunc,
		Run:               emptyRun,
	}
	rootCmd.AddCommand(child)

	buf := new(bytes.Buffer)
	rootCmd.GenBashCompletion(buf)
	output := buf.String()

	check(t, output, "has_completion_function=1")
}

func TestNoValidArgsFuncInScript(t *testing.T) {
	rootCmd := &Command{Use: "root", Args: NoArgs, Run: emptyRun}
	child := &Command{
		Use: "child",
		Run: emptyRun,
	}
	rootCmd.AddCommand(child)

	buf := new(bytes.Buffer)
	rootCmd.GenBashCompletion(buf)
	output := buf.String()

	checkOmit(t, output, "has_completion_function=1")
}

func TestFlagCompletionInGo(t *testing.T) {
	rootCmd := &Command{
		Use: "root",
		Run: emptyRun,
	}
	rootCmd.Flags().IntP("introot", "i", -1, "help message for flag introot")
	rootCmd.RegisterFlagCompletionFunc("introot", func(cmd *Command, args []string, toComplete string) ([]string, BashCompDirective) {
		completions := []string{}
		for _, comp := range []string{"1", "2", "10"} {
			if strings.HasPrefix(comp, toComplete) {
				completions = append(completions, comp)
			}
		}
		return completions, BashCompDirectiveDefault
	})
	rootCmd.Flags().String("filename", "", "Enter a filename")
	rootCmd.RegisterFlagCompletionFunc("filename", func(cmd *Command, args []string, toComplete string) ([]string, BashCompDirective) {
		completions := []string{}
		for _, comp := range []string{"file.yaml", "myfile.json", "file.xml"} {
			if strings.HasPrefix(comp, toComplete) {
				completions = append(completions, comp)
			}
		}
		return completions, BashCompDirectiveNoSpace | BashCompDirectiveNoFileComp
	})

	// Test completing an empty string
	output, err := executeCommand(rootCmd, CompRequestCmd, "--introot", "")
	if err != nil {
		t.Errorf("Unexpected error: %v", err)
	}

	expected := strings.Join([]string{
		"1",
		"2",
		"10",
		":0",
		"Completion ended with directive: BashCompDirectiveDefault", ""}, "\n")

	if output != expected {
		t.Errorf("expected: %q, got: %q", expected, output)
	}

	// Check completing with a prefix
	output, err = executeCommand(rootCmd, CompRequestCmd, "--introot", "1")
	if err != nil {
		t.Errorf("Unexpected error: %v", err)
	}

	expected = strings.Join([]string{
		"1",
		"10",
		":0",
		"Completion ended with directive: BashCompDirectiveDefault", ""}, "\n")

	if output != expected {
		t.Errorf("expected: %q, got: %q", expected, output)
	}

	// Test completing an empty string
	output, err = executeCommand(rootCmd, CompRequestCmd, "--filename", "")
	if err != nil {
		t.Errorf("Unexpected error: %v", err)
	}

	expected = strings.Join([]string{
		"file.yaml",
		"myfile.json",
		"file.xml",
		":6",
		"Completion ended with directive: BashCompDirectiveNoSpace, BashCompDirectiveNoFileComp", ""}, "\n")

	if output != expected {
		t.Errorf("expected: %q, got: %q", expected, output)
	}

	// Check completing with a prefix
	output, err = executeCommand(rootCmd, CompRequestCmd, "--filename", "f")
	if err != nil {
		t.Errorf("Unexpected error: %v", err)
	}

	expected = strings.Join([]string{
		"file.yaml",
		"file.xml",
		":6",
		"Completion ended with directive: BashCompDirectiveNoSpace, BashCompDirectiveNoFileComp", ""}, "\n")

	if output != expected {
		t.Errorf("expected: %q, got: %q", expected, output)
	}
}