package main

import (
	"bytes"
	"encoding/json"
	"errors"
	"strings"
	"testing"

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

type deviceInfoOutput struct {
	Devices []keyboardLine        `json:"devices"`
	Total   int                   `json:"total"`
	Others  []intdevice.HIDDevice `json:"otherHidDevices"`
}

// stubDiscovery replaces both enumerations the command makes. Only the
// keyboards are of interest to most tests, so the devices that were passed over
// are stubbed empty as well: leaving that one real would make the output depend
// on what is plugged into the machine running the tests.
func stubDiscovery(t *testing.T, devices []intdevice.Device) {
	t.Helper()
	orig, origOther := discoverAll, discoverOther
	discoverAll = func() ([]intdevice.Device, error) { return devices, nil }
	discoverOther = func() ([]intdevice.HIDDevice, error) { return nil, nil }
	t.Cleanup(func() { discoverAll, discoverOther = orig, origOther })
}

// runRealKeyboardInfo executes the shipped command so a re-added
// human-readable banner is caught, not just changes inside a helper.
func runRealKeyboardInfo(t *testing.T) (stdout, stderr string, err error) {
	t.Helper()

	var out, errOut bytes.Buffer
	keyboardInfoCmd.SetOut(&out)
	keyboardInfoCmd.SetErr(&errOut)
	// Restored to nil rather than to whatever it was: OutOrStdout() answers
	// os.Stdout, and setting that back leaves the command with a writer of its
	// own, which a root's SetOut can no longer override. The next test that ran
	// this command through a root would then print its help to the terminal.
	t.Cleanup(func() {
		keyboardInfoCmd.SetOut(nil)
		keyboardInfoCmd.SetErr(nil)
	})

	err = keyboardInfoCmd.RunE(keyboardInfoCmd, nil)
	return out.String(), errOut.String(), err
}

func TestKeyboardInfoWritesOnlyJSON(t *testing.T) {
	withJSON(t)
	stubDiscovery(t, []intdevice.Device{
		{Index: 1, Path: "/dev/hidraw7", VendorID: 0x36b0, ProductID: 0x309f, Name: "Impact 80"},
	})

	stdout, stderr, err := runRealKeyboardInfo(t)
	if err != nil {
		t.Fatalf("keyboard info returned error: %v", err)
	}

	if stderr != "" {
		t.Errorf("keyboard info wrote %q to stderr, want no human-readable banner next to the JSON", stderr)
	}

	var got deviceInfoOutput
	if err := json.Unmarshal([]byte(stdout), &got); err != nil {
		t.Fatalf("stdout is not valid JSON: %v (output %q)", err, stdout)
	}
	if got.Total != 1 {
		t.Errorf("total = %d, want 1", got.Total)
	}
	if len(got.Devices) != 1 {
		t.Fatalf("devices = %d entries, want 1", len(got.Devices))
	}
	if got.Devices[0].Index != 1 {
		t.Errorf("devices[0].index = %d, want 1", got.Devices[0].Index)
	}
	if got.Devices[0].Path != "/dev/hidraw7" {
		t.Errorf("devices[0].path = %q, want %q", got.Devices[0].Path, "/dev/hidraw7")
	}
}

func TestKeyboardInfoEmitsIndentedJSON(t *testing.T) {
	withJSON(t)
	stubDiscovery(t, []intdevice.Device{
		{Index: 1, Path: "/dev/hidraw7", Name: "Impact 80"},
	})

	stdout, _, err := runRealKeyboardInfo(t)
	if err != nil {
		t.Fatalf("keyboard info returned error: %v", err)
	}

	if !strings.Contains(stdout, "\n  \"devices\": [") {
		t.Errorf("stdout = %q, want two-space indented JSON like the other commands emit", stdout)
	}
	if !strings.HasSuffix(stdout, "\n") {
		t.Errorf("stdout = %q, want a trailing newline", stdout)
	}
}

func TestKeyboardInfoEmitsEmptyArrayNotNull(t *testing.T) {
	withJSON(t)
	stubDiscovery(t, nil)

	stdout, _, err := runRealKeyboardInfo(t)
	if err != nil {
		t.Fatalf("keyboard info returned error: %v", err)
	}

	if !strings.Contains(stdout, `"devices": []`) {
		t.Errorf("stdout = %q, want an empty array so consumers can iterate unconditionally", stdout)
	}
	if !strings.Contains(stdout, `"otherHidDevices": []`) {
		t.Errorf("stdout = %q, want the passed-over devices as an empty array, not null", stdout)
	}
}

// An empty result is the one case a user cannot read on their own: it looks the
// same whether the keyboard is unplugged or its lighting is on a HID collection
// this tool does not address. So the listing names the devices that are there,
// with the usage pages they do expose — the missing 0xFF60/0x61 is the finding.
func TestKeyboardInfoEmptyResultNamesTheDevicesPassedOver(t *testing.T) {
	stubDiscovery(t, nil)
	stubOtherDiscovery(t, []intdevice.HIDDevice{
		{
			VendorID:  0x320f,
			ProductID: 0x5044,
			Name:      "GMMK Pro",
			UsagePairs: []intdevice.UsagePair{
				{UsagePage: 0x0001, Usage: 0x06},
				{UsagePage: 0xff80, Usage: 0x61},
			},
		},
	})

	stdout, _, err := runRealKeyboardInfo(t)
	if err != nil {
		t.Fatalf("keyboard info returned error: %v", err)
	}

	for _, want := range []string{
		"No keyboard with the QMK Raw HID interface found",
		"usage page 0xFF60, usage 0x61",
		"0x320F/0x5044",
		"GMMK Pro",
		"0xFF80/0x61",
	} {
		if !strings.Contains(stdout, want) {
			t.Errorf("stdout = %q, want it to contain %q", stdout, want)
		}
	}
}

// The preamble says what was looked for and why a board has it, and it must not
// claim VIA was checked: nothing is opened here, and VIA is never what the
// collection filter asks about. A sentence that says it did would send a user
// looking for a probe that does not exist.
func TestKeyboardInfoEmptyResultDoesNotClaimToHaveCheckedVIA(t *testing.T) {
	stubDiscovery(t, nil)
	stubOtherDiscovery(t, nil)

	stdout, _, err := runRealKeyboardInfo(t)
	if err != nil {
		t.Fatalf("keyboard info returned error: %v", err)
	}

	if !strings.Contains(stdout, "VIA's build cannot be built without it") {
		t.Errorf("stdout = %q, want it to say why a QMK firmware has the collection", stdout)
	}
	if strings.Contains(stdout, "no VIA") || strings.Contains(stdout, "does not support VIA") {
		t.Errorf("stdout = %q, want no claim about VIA: this command never opened the board", stdout)
	}
}

// And the opposite: a keyboard was found, so the devices that were passed over
// are only ever a dock or a mouse, and a listing beside the line the user came
// for buries it.
func TestKeyboardInfoListsOtherDevicesOnlyWhenNoneWasFound(t *testing.T) {
	stubDiscovery(t, []intdevice.Device{
		{Index: 1, Path: "/dev/hidraw7", VendorID: 0x36b0, ProductID: 0x309f, Name: "Impact 80"},
	})
	stubOtherDiscovery(t, []intdevice.HIDDevice{
		{VendorID: 0x046d, ProductID: 0xc041, Name: "USB Gaming Mouse",
			UsagePairs: []intdevice.UsagePair{{UsagePage: 0xff00, Usage: 0x01}}},
	})

	stdout, _, err := runRealKeyboardInfo(t)
	if err != nil {
		t.Fatalf("keyboard info returned error: %v", err)
	}

	if !strings.Contains(stdout, "Impact 80") {
		t.Errorf("stdout = %q, want the keyboard that was found", stdout)
	}
	if strings.Contains(stdout, "USB Gaming Mouse") {
		t.Errorf("stdout = %q, want no listing of passed-over devices when a keyboard was found", stdout)
	}
}

// With nothing found and nothing else connected, the sentence has to say that
// rather than print a heading with nothing under it.
func TestKeyboardInfoEmptyResultWithNoHIDDevicesAtAll(t *testing.T) {
	stubDiscovery(t, nil)
	stubOtherDiscovery(t, nil)

	stdout, _, err := runRealKeyboardInfo(t)
	if err != nil {
		t.Fatalf("keyboard info returned error: %v", err)
	}

	if !strings.Contains(stdout, "No other HID device is connected") {
		t.Errorf("stdout = %q, want it to say that no HID device is connected", stdout)
	}
	if strings.Contains(stdout, "These HID devices are connected") {
		t.Errorf("stdout = %q, want no heading for a list that is not there", stdout)
	}
}

// A consumer asking "why not this one" reads the JSON, so the devices that were
// passed over are in it whether or not a keyboard was found.
func TestKeyboardInfoJSONCarriesTheOtherHIDDevicesWhateverItFinds(t *testing.T) {
	withJSON(t)
	stubDiscovery(t, []intdevice.Device{
		{Index: 1, Path: "/dev/hidraw7", VendorID: 0x36b0, ProductID: 0x309f, Name: "Impact 80"},
	})
	stubOtherDiscovery(t, []intdevice.HIDDevice{
		{VendorID: 0x320f, ProductID: 0x5044, Name: "GMMK Pro",
			UsagePairs: []intdevice.UsagePair{{UsagePage: 0xff80, Usage: 0x61}}},
	})

	stdout, _, err := runRealKeyboardInfo(t)
	if err != nil {
		t.Fatalf("keyboard info returned error: %v", err)
	}

	var got deviceInfoOutput
	if err := json.Unmarshal([]byte(stdout), &got); err != nil {
		t.Fatalf("stdout is not valid JSON: %v (output %q)", err, stdout)
	}
	if len(got.Devices) != 1 {
		t.Fatalf("devices = %d entries, want 1", len(got.Devices))
	}
	if len(got.Others) != 1 {
		t.Fatalf("otherHidDevices = %d entries, want 1", len(got.Others))
	}
	if got.Others[0].VendorID != 0x320f {
		t.Errorf("otherHidDevices[0].vendorId = %04X, want 320F", got.Others[0].VendorID)
	}
	if len(got.Others[0].UsagePairs) != 1 || got.Others[0].UsagePairs[0].UsagePage != 0xff80 {
		t.Errorf("otherHidDevices[0].usagePages = %+v, want the page it was passed over for", got.Others[0].UsagePairs)
	}
}

// The passed-over devices are never selectable, so they carry no index and none
// is printed: a number there would be one --device does not take.
func TestKeyboardInfoGivesNoNumberToADeviceThatCannotBeSelected(t *testing.T) {
	stubDiscovery(t, nil)
	stubOtherDiscovery(t, []intdevice.HIDDevice{
		{VendorID: 0x320f, ProductID: 0x5044, Name: "GMMK Pro",
			UsagePairs: []intdevice.UsagePair{{UsagePage: 0xff80, Usage: 0x61}}},
	})

	stdout, _, err := runRealKeyboardInfo(t)
	if err != nil {
		t.Fatalf("keyboard info returned error: %v", err)
	}

	for _, line := range strings.Split(stdout, "\n") {
		if !strings.Contains(line, "0x320F/0x5044") {
			continue
		}
		if strings.HasPrefix(strings.TrimSpace(line), "1 ") {
			t.Errorf("stdout = %q, want no number on a device --device cannot select", stdout)
		}
	}
}

func stubOtherDiscovery(t *testing.T, others []intdevice.HIDDevice) {
	t.Helper()
	orig := discoverOther
	discoverOther = func() ([]intdevice.HIDDevice, error) { return others, nil }
	t.Cleanup(func() { discoverOther = orig })
}

func TestKeyboardInfoPropagatesDiscoveryError(t *testing.T) {
	orig := discoverAll
	discoverAll = func() ([]intdevice.Device, error) { return nil, errStub }
	t.Cleanup(func() { discoverAll = orig })

	_, _, err := runRealKeyboardInfo(t)
	if err == nil {
		t.Fatal("keyboard info expected discovery error, got nil")
	}
	if !strings.Contains(err.Error(), "enumerate") {
		t.Errorf("error = %v, want it to wrap the discovery failure", err)
	}
}

var errStub = errors.New("enumerate: stub failure")

// A command that a test gave a writer of its own keeps it, and a writer set that
// way outranks the root's. Restoring os.Stdout rather than nil therefore left the
// shipped `keyboard info` writing to the terminal while a later test believed it
// was capturing its help, and the failure showed up as noise in an unrelated
// test's output rather than as a failing one.
func TestKeyboardInfoHelpGoesWhereTheRootSendsIt(t *testing.T) {
	// In a subtest, so the restore has happened by the time the help runs: that
	// ordering is the whole defect, and doing both here would not test it.
	t.Run("a test gave it a writer", func(t *testing.T) {
		runRealKeyboardInfo(t)
	})

	var out bytes.Buffer
	root := newRootCommand()
	registerCommands(root)
	root.SetOut(&out)
	root.SetErr(&out)
	root.SetArgs([]string{"keyboard", "info", "--help"})

	if err := root.Execute(); err != nil {
		t.Fatalf("keyboard info --help returned error: %v", err)
	}
	if !strings.Contains(out.String(), "Usage:") {
		t.Errorf("captured %q, want the help, so the root's writer is in charge", out.String())
	}
}