package metrics

// A trimmed PCI ID database, embedded, so a GPU is named the same on every machine —
// "Intel UHD Graphics 600" — whether or not that machine has pciutils. OpenWrt has neither
// lspci nor pci.ids, and the router's GPU came up as "Intel GPU 3185" beside its twin's
// "Intel UHD Graphics 600" until this. scripts/pci-ids-gpu.sh regenerates the file.

import (
	_ "embed"
	"strings"
	"sync"
)

//go:embed pciids_gpu.txt
var pciIDsGPU string

var pciTable struct {
	once    sync.Once
	vendors map[string]string // "8086" → "Intel Corporation"
	devices map[string]string // "8086:3185" → "GeminiLake [UHD Graphics 600]"
}

// pciName looks a vendor and device ID up (hex, lower case, no 0x): the vendor's name and
// the device's; empty where unknown.
func pciName(vendor, device string) (string, string) {
	pciTable.once.Do(func() {
		pciTable.vendors, pciTable.devices = map[string]string{}, map[string]string{}
		cur := ""
		for _, line := range strings.Split(pciIDsGPU, "\n") {
			switch {
			case line == "" || line[0] == '#':
			case line[0] == '\t':
				if cur == "" || len(line) < 7 || line[1] == '\t' {
					continue // a subsystem, or a device before any vendor
				}
				pciTable.devices[cur+":"+line[1:5]] = strings.TrimSpace(line[5:])
			default:
				if len(line) >= 6 {
					cur = line[:4]
					pciTable.vendors[cur] = strings.TrimSpace(line[4:])
				}
			}
		}
	})
	vendor, device = strings.ToLower(vendor), strings.ToLower(device)
	return pciTable.vendors[vendor], pciTable.devices[vendor+":"+device]
}