package main

import (
	"errors"
	"os"
	"path/filepath"
	"strings"
	"testing"

	"github.com/spf13/cobra"

	intdevice "netdome.biz/paul/qmk-rgb/internal/device"
)

// The tool knows what a zone may be, but the shell only offers what the binary
// tells it about. The zone is a positional argument, so the completion hangs off
// the command rather than off a flag, and a board's own channel names come from
// a definition file the tool reads.
func TestZoneCompletionOffersSubsystemsAndTheBoardsOwnNames(t *testing.T) {
	dir := t.TempDir()
	writeDefinition(t, dir, "impact80.json", `{
		"name": "Impact 80", "vendorId": "0x36B0", "productId": "0x309F",
		"menus": [{"label":"Lighting","content":[
			{"label":"logo","content":[{"label":"Effect","type":"dropdown",
			 "content":["id_qmk_rgblight_effect",2,2],"options":["none"]}]},
			{"label":"Backlight","content":[{"label":"Effect","type":"dropdown",
			 "content":["id_qmk_rgb_matrix_effect",3,2],"options":["none"]}]}]}]}`)
	t.Cleanup(forceDefinitionsDir(t, dir))

	got, directive := completeZoneNames(nil, nil, "")
	if directive != cobra.ShellCompDirectiveNoFileComp {
		t.Errorf("directive = %v, want NoFileComp so the shell does not fall back to paths", directive)
	}

	for _, want := range []string{"backlight", "rgblight", "rgb_matrix", "audio", "led_matrix", "logo", "Backlight"} {
		if !contains(got, want) {
			t.Errorf("completeZoneNames() = %v, want it to offer %q", got, want)
		}
	}
	// Nothing is offered twice: Backlight is both a label and close to
	// backlight, and a list with repeats reads as a bug.
	if len(got) != countDistinct(got) {
		t.Errorf("completeZoneNames() = %v, want no duplicates", got)
	}
}

// The shell is completing as the user types, so a prefix has to narrow the list.
func TestZoneCompletionNarrowsToThePrefix(t *testing.T) {
	t.Cleanup(forceDefinitionsDir(t, t.TempDir()))

	got, directive := completeZoneNames(nil, nil, "rgb")
	if directive != cobra.ShellCompDirectiveNoFileComp {
		t.Errorf("directive = %v, want NoFileComp so the shell does not fall back to paths", directive)
	}
	for _, g := range got {
		if !strings.HasPrefix(g, "rgb") {
			t.Errorf("completeZoneNames(%q) = %v, want only names with that prefix", "rgb", got)
		}
	}
	if !contains(got, "rgb_matrix") {
		t.Errorf("completeZoneNames(\"rgb\") = %v, want rgb_matrix", got)
	}
}

// `all` is a zone name like any other, and the shell has to offer it: it is the
// one spelling that reaches every channel, and a user who cannot see it will not
// reach every channel.
func TestZoneCompletionOffersAll(t *testing.T) {
	t.Cleanup(forceDefinitionsDir(t, t.TempDir()))

	got, _ := completeZoneNames(nil, nil, "")
	if !contains(got, "all") {
		t.Errorf("completeZoneNames() = %v, want it to offer \"all\"", got)
	}
}

// A board's own names come from a definition file, and the one built into the
// binary counts as much as one in the data directory. `go install` creates no
// data directory, so a shell that only read that one would offer a board nothing
// but the subsystem names — and the subsystem names a board renamed are not the
// names it answers to.
func TestZoneCompletionOffersTheBuiltInDefinitionsToo(t *testing.T) {
	t.Cleanup(forceDefinitionsDir(t, t.TempDir()))

	got, _ := completeZoneNames(nil, nil, "")
	// The Impact 80's file is the one that ships, and it names three channels.
	for _, want := range []string{"logo", "Backlight", "side"} {
		if !contains(got, want) {
			t.Errorf("completeZoneNames() = %v, want the built-in definition's name %q", got, want)
		}
	}
}

// The zone is a positional argument now, so the completion hangs off the command
// rather than off a flag, and it stops after the first argument rather than
// offering a channel where a value belongs.
func TestZoneCompletionIsOnTheCommandNotTheFlag(t *testing.T) {
	lighting := map[string]*cobra.Command{
		"effect":     NewEffectCmd(),
		"brightness": NewBrightnessCmd(),
		"speed":      NewSpeedCmd(),
		"color":      NewColorCmd(),
		"enable":     NewEnableCmd(),
		"disable":    NewDisableCmd(),
		"info":       NewInfoCmd(),
	}

	for name, cmd := range lighting {
		t.Run(name, func(t *testing.T) {
			if cmd.ValidArgsFunction == nil {
				t.Fatalf("%s has no ValidArgsFunction, want the shell offered the zone names", name)
			}
			got, _ := cmd.ValidArgsFunction(cmd, nil, "")
			if !contains(got, "all") {
				t.Errorf("%s completion = %v, want it to offer the zones", name, got)
			}
			// After the zone, the next argument is a value or a name the tool
			// cannot know without opening the keyboard.
			after, directive := cmd.ValidArgsFunction(cmd, []string{"logo"}, "")
			if len(after) != 0 {
				t.Errorf("%s completion after a zone = %v, want nothing", name, after)
			}
			if directive != cobra.ShellCompDirectiveNoFileComp {
				t.Errorf("%s directive = %v, want NoFileComp", name, directive)
			}
		})
	}
}

// `load` takes a profile name first and a zone second, in that order, so the two
// completions cannot be swapped without offering something that does not exist.
func TestLoadCompletionIsAProfileThenAZone(t *testing.T) {
	t.Cleanup(forceDefinitionsDir(t, t.TempDir()))

	cmd := NewProfileLoadCmd()
	first, _ := cmd.ValidArgsFunction(cmd, nil, "")
	if !contains(first, "lava") {
		t.Errorf("load completion = %v, want the profile names", first)
	}

	second, _ := cmd.ValidArgsFunction(cmd, []string{"lava"}, "")
	if contains(second, "lava") {
		t.Errorf("load completion after a name = %v, want zones, not more profiles", second)
	}
	if !contains(second, "all") {
		t.Errorf("load completion after a name = %v, want the zone names", second)
	}
}

// A command that cannot address a channel offers no zone, so the shell does not
// suggest one where there is none to use. `delete` completes a profile name, so
// what matters is that the candidates are the names, not the channels.
func TestCommandsWithoutAChannelOfferNoZone(t *testing.T) {
	for name, cmd := range map[string]*cobra.Command{
		"list": NewProfileListCmd(),
		"save": NewProfileSaveCmd(),
	} {
		t.Run(name, func(t *testing.T) {
			if cmd.ValidArgsFunction != nil {
				t.Errorf("%s offers completion, want only the commands that name a channel to", name)
			}
		})
	}

	profiles, _ := NewProfileDeleteCmd().ValidArgsFunction(nil, nil, "")
	for _, candidate := range profiles {
		if candidate == "all" || candidate == "rgb_matrix" {
			t.Errorf("delete completion = %v, want profile names, not channels", profiles)
		}
	}
}

// A definition that is not there must not break completion: a shell prints the
// error text, which is worse than offering nothing.
func TestZoneCompletionSurvivesAMissingDataDirectory(t *testing.T) {
	t.Cleanup(forceDefinitionsDir(t, filepath.Join(t.TempDir(), "absent")))

	got, directive := completeZoneNames(nil, nil, "")
	if directive != cobra.ShellCompDirectiveNoFileComp {
		t.Errorf("directive = %v, want NoFileComp so the shell does not fall back to paths", directive)
	}
	if !contains(got, "rgb_matrix") {
		t.Errorf("completeZoneNames() = %v, want the QMK subsystem names at least", got)
	}
}

// --device takes the numbers keyboard info prints, which come from enumeration
// alone and need no open keyboard.
func TestDeviceCompletionOffersTheConnectedKeyboards(t *testing.T) {
	original := discoverAll
	discoverAll = func() ([]intdevice.Device, error) {
		return []intdevice.Device{{Index: 1}, {Index: 2}}, nil
	}
	t.Cleanup(func() { discoverAll = original })

	got, directive := completeDeviceNumbers(nil, nil, "")
	if directive != cobra.ShellCompDirectiveNoFileComp {
		t.Errorf("directive = %v, want NoFileComp so the shell does not fall back to paths", directive)
	}
	if len(got) != 2 || got[0] != "1" || got[1] != "2" {
		t.Errorf("completeDeviceNumbers() = %v, want [1 2]", got)
	}
}

func TestDeviceCompletionSurvivesADiscoveryFailure(t *testing.T) {
	original := discoverAll
	discoverAll = func() ([]intdevice.Device, error) { return nil, errors.New("no keyboard") }
	t.Cleanup(func() { discoverAll = original })

	got, directive := completeDeviceNumbers(nil, nil, "")
	if directive != cobra.ShellCompDirectiveNoFileComp {
		t.Errorf("directive = %v, want NoFileComp so the shell does not fall back to paths", directive)
	}
	if len(got) != 0 {
		t.Errorf("completeDeviceNumbers() = %v, want nothing when discovery fails", got)
	}
}

// load, save and delete take a profile name, and the names in profiles/ are
// readable without a keyboard — which is the point, because the shell is asking
// while nothing is plugged in.
func TestProfileNameCompletionOffersTheFilesInTheDirectory(t *testing.T) {
	dir := t.TempDir()
	original := profilesDirOverride
	profilesDirOverride = dir
	t.Cleanup(func() { profilesDirOverride = original })

	for _, name := range []string{"paul.json", "default.json", "notes.txt"} {
		if err := os.WriteFile(filepath.Join(dir, name), []byte("{}"), 0o600); err != nil {
			t.Fatal(err)
		}
	}

	for _, cmd := range []*cobra.Command{NewProfileLoadCmd(), NewProfileDeleteCmd()} {
		got, _ := completeProfileNames(cmd, nil, "")
		if len(got) != 2 || got[0] != "default" || got[1] != "paul" {
			t.Errorf("completeProfileNames() = %v, want [default paul]", got)
		}
	}
}

func TestProfileNameCompletionSurvivesAMissingDirectory(t *testing.T) {
	original := profilesDirOverride
	profilesDirOverride = filepath.Join(t.TempDir(), "absent")
	t.Cleanup(func() { profilesDirOverride = original })

	got, directive := completeProfileNames(nil, nil, "")
	if directive != cobra.ShellCompDirectiveNoFileComp {
		t.Errorf("directive = %v, want NoFileComp so the shell does not fall back to paths", directive)
	}
	if len(got) != 0 {
		t.Errorf("completeProfileNames() = %v, want nothing", got)
	}
}

func contains(list []string, want string) bool {
	for _, s := range list {
		if s == want {
			return true
		}
	}
	return false
}

func countDistinct(list []string) int {
	seen := make(map[string]bool, len(list))
	for _, s := range list {
		seen[s] = true
	}
	return len(seen)
}