package main

import (
	"flag"
	"fmt"
	"os"

	"go.einride.tech/can/pkg/dbc"
)

const dev = "can0"

type Signals struct {
	tach, speed, an1, an2, an3, an4 *dbc.SignalDef
}

// Flags
var (
	// DBC file
	dbcFilenameFlag = "dbc"
	dbcFilename = flag.String(dbcFilenameFlag, "", "DBC file name")

	// Signal names
	tachSigFlag = "tachSig"
	speedSigFlag = "speedSig"
	an1SigFlag = "an1Sig"
	an2SigFlag = "an2Sig"
	an3SigFlag = "an3Sig"
	an4SigFlag = "an4Sig"
	tachSig = flag.String(tachSigFlag, "", "tachometer signal name")
	speedSig = flag.String(speedSigFlag, "", "speedometer signal name")
	an1Sig = flag.String(an1SigFlag, "", "analog channel 1 signal name")
	an2Sig = flag.String(an2SigFlag, "", "analog channel 2 signal name")
	an3Sig = flag.String(an3SigFlag, "", "analog channel 3 signal name")
	an4Sig = flag.String(an4SigFlag, "", "analog channel 4 signal name")

	// Calibration tables
	// TODO
)

func main() {
	// Parse command line args
	flag.Parse()
	if *dbcFilename == "" {
		weprintf("Missing '%s' flag.\n", dbcFilenameFlag)
		flag.Usage()
		os.Exit(1)
	}

	// Parse DBC file
	msgDefs, err := parseDbcFile(*dbcFilename)
	if err != nil {
		eprintf("Error parsing %s: %v\n", *dbcFilename, err)
	}


	for _, msg := range msgDefs {
		for _, sig := range msg.Signals {
			fmt.Println(sig)
		}
	}
}

func parseDbcFile(filename string) ([]*dbc.MessageDef, error) {
	// Read file
	buf, err := os.ReadFile(filename)
	if err != nil {
		return nil, err
	}

	// Parse file
	parser := dbc.NewParser(filename, buf)
	if err := parser.Parse(); err != nil {
		return nil, err
	}

	// Filter message definitions
	defs := parser.Defs()
	msgDefs := make([]*dbc.MessageDef, 0, len(defs))
	for _, def := range defs {
		if msg, ok := def.(*dbc.MessageDef); ok {
			msgDefs = append(msgDefs, msg)
		}
	}
	return msgDefs, nil
}

func eprintf(format string, a ...any) {
	weprintf(format, a...)
	os.Exit(1)
}

func weprintf(format string, a ...any) {
	fmt.Fprintf(os.Stderr, format, a...)
}