package main

import (
	"context"
	"errors"
	"fmt"
	"log"
	"os"
	"os/signal"
	"path/filepath"
	"runtime"
	"syscall"
	"unique"

	"hakurei.app/command"
	"hakurei.app/container"
	"hakurei.app/container/check"
	"hakurei.app/internal/pkg"
	"hakurei.app/internal/rosa"
	"hakurei.app/message"
)

func main() {
	container.TryArgv0(nil)

	log.SetFlags(0)
	log.SetPrefix("mbf: ")
	msg := message.New(log.Default())

	if os.Geteuid() == 0 {
		log.Fatal("this program must not run as root")
	}

	var cache *pkg.Cache
	ctx, stop := signal.NotifyContext(context.Background(),
		syscall.SIGINT, syscall.SIGTERM, syscall.SIGHUP)
	defer stop()
	defer func() {
		if cache != nil {
			cache.Close()
		}

		if r := recover(); r != nil {
			fmt.Println(r)
			log.Fatal("consider scrubbing the on-disk cache")
		}
	}()

	var (
		flagVerbose bool
		flagCures   int
		flagBase    string
		flagTShift  int
	)
	c := command.New(os.Stderr, log.Printf, "mbf", func([]string) (err error) {
		msg.SwapVerbose(flagVerbose)

		var base *check.Absolute
		if flagBase, err = filepath.Abs(flagBase); err != nil {
			return
		} else if base, err = check.NewAbs(flagBase); err != nil {
			return
		}
		if cache, err = pkg.Open(ctx, msg, flagCures, base); err == nil {
			if flagTShift < 0 || flagTShift > 31 {
				flagTShift = 31
			}
			cache.SetThreshold(1 << flagTShift)
		}
		return
	}).Flag(
		&flagVerbose,
		"v", command.BoolFlag(false),
		"Print cure messages to the console",
	).Flag(
		&flagCures,
		"cures", command.IntFlag(0),
		"Maximum number of dependencies to cure at any given time",
	).Flag(
		&flagBase,
		"d", command.StringFlag("cache"),
		"Directory to store cured artifacts",
	).Flag(
		&flagTShift,
		"tshift", command.IntFlag(31),
		"Dependency graph size exponent, to the power of 2",
	)

	{
		var flagShifts int
		c.NewCommand(
			"scrub", "Examine the on-disk cache for errors",
			func(args []string) error {
				if len(args) > 0 {
					return errors.New("scrub expects no arguments")
				}
				if flagShifts < 0 || flagShifts > 31 {
					flagShifts = 12
				}
				return cache.Scrub(runtime.NumCPU() << flagShifts)
			},
		).Flag(
			&flagShifts,
			"shift", command.IntFlag(12),
			"Scrub parallelism size exponent, to the power of 2",
		)
	}

	c.NewCommand(
		"stage3",
		"Check for toolchain 3-stage non-determinism",
		func(args []string) (err error) {
			_, _, _, stage2 := (rosa.Std - 1).NewLLVM()
			_, _, _, stage3 := rosa.Std.NewLLVM()
			var (
				pathname *check.Absolute
				checksum [2]unique.Handle[pkg.Checksum]
			)

			if pathname, checksum[0], err = cache.Cure(stage2); err != nil {
				return err
			}
			log.Println("stage2:", pathname)
			if pathname, checksum[1], err = cache.Cure(stage3); err != nil {
				return err
			}
			log.Println("stage3:", pathname)

			if checksum[0] != checksum[1] {
				err = &pkg.ChecksumMismatchError{
					Got:  checksum[0].Value(),
					Want: checksum[1].Value(),
				}
			}
			return
		},
	)

	c.NewCommand(
		"cure",
		"Cure the named artifact and show its path",
		func(args []string) error {
			if len(args) != 1 {
				return errors.New("cure requires 1 argument")
			}
			var a pkg.Artifact
			switch args[0] {
			case "busybox":
				a = rosa.Std.NewBusybox()
			case "musl":
				a = rosa.Std.NewMusl(nil)
			case "go":
				a = rosa.Std.NewGo()
			case "rsync":
				a = rosa.Std.NewRsync()

			default:
				return fmt.Errorf("unsupported artifact %q", args[0])
			}

			pathname, _, err := cache.Cure(a)
			if err == nil {
				log.Println(pathname)
			}
			return err

		},
	)

	c.MustParse(os.Args[1:], func(err error) {
		if cache != nil {
			cache.Close()
		}
		log.Fatal(err)
	})
}