package device

import (
	"fmt"
	"sort"

	"netdome.biz/paul/qmk-rgb/internal/hid"
)

// Device is a connected QMK Raw HID keyboard.
// Index is 1-based and is what --device accepts.
type Device struct {
	Index     int    `json:"index"`
	Path      string `json:"path"`
	VendorID  uint16 `json:"vendorId"`
	ProductID uint16 `json:"productId"`
	Name      string `json:"name,omitempty"`
}

// DiscoverAll returns every connected QMK Raw HID keyboard, ordered
// deterministically and numbered from 1. A keyboard that does not report a USB
// product string comes back with no Name; that costs the name and nothing else.
func DiscoverAll() ([]Device, error) {
	infos, err := hid.DiscoverAll()
	if err != nil {
		return nil, fmt.Errorf("discover qmk devices: %w", err)
	}

	devices := make([]Device, 0, len(infos))
	for _, info := range infos {
		devices = append(devices, Device{
			Path:      info.Path,
			VendorID:  info.VendorID,
			ProductID: info.ProductID,
			Name:      info.ProductString,
		})
	}

	return indexDevices(devices), nil
}

// indexDevices sorts devices deterministically and assigns 1-based indexes.
// The input slice is left untouched.
func indexDevices(devices []Device) []Device {
	sorted := make([]Device, len(devices))
	copy(sorted, devices)

	sort.SliceStable(sorted, func(i, j int) bool {
		a, b := sorted[i], sorted[j]
		switch {
		case a.VendorID != b.VendorID:
			return a.VendorID < b.VendorID
		case a.ProductID != b.ProductID:
			return a.ProductID < b.ProductID
		default:
			return a.Path < b.Path
		}
	})

	for i := range sorted {
		sorted[i].Index = i + 1
	}

	return sorted
}