// Package bootstate parses kernel cmdline parameters that the
// orchestrator baked into the iPXE script. The agent consumes these
// on startup to learn which run it belongs to and how to reach back.
package bootstate

import (
	"errors"
	"fmt"
	"os"
	"strconv"
	"strings"
)

type Params struct {
	OrchestratorURL string
	RunID           int64
	MAC             string
	Token           string
	TLSCertFPR      string // optional
}

// ParseCmdline reads /proc/cmdline (or a user-supplied path for tests)
// and pulls out the vetting.* parameters.
func ParseCmdline(path string) (*Params, error) {
	if path == "" {
		path = "/proc/cmdline"
	}
	b, err := os.ReadFile(path)
	if err != nil {
		return nil, fmt.Errorf("read %s: %w", path, err)
	}
	return ParseCmdlineString(string(b))
}

func ParseCmdlineString(s string) (*Params, error) {
	fields := strings.Fields(strings.TrimSpace(s))
	var p Params
	for _, f := range fields {
		k, v, ok := strings.Cut(f, "=")
		if !ok {
			continue
		}
		switch k {
		case "vetting.orchestrator":
			p.OrchestratorURL = v
		case "vetting.run_id":
			id, err := strconv.ParseInt(v, 10, 64)
			if err != nil {
				return nil, fmt.Errorf("vetting.run_id=%q: %w", v, err)
			}
			p.RunID = id
		case "vetting.mac":
			p.MAC = strings.ToLower(v)
		case "vetting.token":
			p.Token = v
		case "vetting.cert_fpr":
			p.TLSCertFPR = v
		}
	}
	if p.OrchestratorURL == "" || p.RunID == 0 || p.MAC == "" || p.Token == "" {
		return nil, errors.New("cmdline missing one of vetting.orchestrator, vetting.run_id, vetting.mac, vetting.token")
	}
	return &p, nil
}