package daemon

import (
	"context"
	"errors"
	"fmt"
	"isle/bootstrap"
	"isle/secrets"

	"code.betamike.com/micropelago/pmux/pmuxlib"
	"dev.mediocregopher.com/mediocre-go-lib.git/mlog"
)

// Children manages all child processes of a network. Child processes are
// comprised of:
// - nebula
// - dnsmasq
// - garage (0 or more, depending on configured storage allocations)
type Children struct {
	logger       *mlog.Logger
	daemonConfig Config
	opts         Opts

	pmux *pmuxlib.Pmux
}

// NewChildren initialized and returns a Children instance. If initialization
// fails an error is returned.
func NewChildren(
	ctx context.Context,
	logger *mlog.Logger,
	binDirPath string,
	secretsStore secrets.Store,
	daemonConfig Config,
	garageAdminToken string,
	hostBootstrap bootstrap.Bootstrap,
	opts *Opts,
) (
	*Children, error,
) {
	opts = opts.withDefaults()

	logger.Info(ctx, "Loading secrets")
	garageRPCSecret, err := getGarageRPCSecret(ctx, secretsStore)
	if err != nil && !errors.Is(err, secrets.ErrNotFound) {
		return nil, fmt.Errorf("loading garage RPC secret: %w", err)
	}

	c := &Children{
		logger:       logger,
		daemonConfig: daemonConfig,
		opts:         *opts,
	}

	pmuxConfig, err := c.newPmuxConfig(
		ctx,
		garageRPCSecret,
		binDirPath,
		daemonConfig,
		garageAdminToken,
		hostBootstrap,
	)
	if err != nil {
		return nil, fmt.Errorf("generating pmux config: %w", err)
	}

	c.pmux = pmuxlib.NewPmux(pmuxConfig, c.opts.Stdout, c.opts.Stderr)

	initErr := c.postPmuxInit(
		ctx, daemonConfig, garageAdminToken, hostBootstrap,
	)
	if initErr != nil {
		logger.Warn(ctx, "failed to initialize Children, shutting down child processes", err)
		if err := c.Shutdown(); err != nil {
			panic(fmt.Sprintf(
				"failed to shut down child processes after initialization"+
					" error, there may be zombie children leftover."+
					" Original error: %v",
				initErr,
			))
		}

		return nil, initErr
	}

	return c, nil
}

// RestartDNSMasq rewrites the dnsmasq config and restarts the process.
func (c *Children) RestartDNSMasq(hostBootstrap bootstrap.Bootstrap) error {
	_, err := dnsmasqWriteConfig(
		c.opts.EnvVars.RuntimeDirPath, c.daemonConfig, hostBootstrap,
	)
	if err != nil {
		return fmt.Errorf("writing new dnsmasq config: %w", err)
	}

	c.pmux.Restart("dnsmasq")
	return nil
}

// RestartNebula rewrites the nebula config and restarts the process.
func (c *Children) RestartNebula(hostBootstrap bootstrap.Bootstrap) error {
	_, err := nebulaWriteConfig(
		c.opts.EnvVars.RuntimeDirPath, c.daemonConfig, hostBootstrap,
	)
	if err != nil {
		return fmt.Errorf("writing a new nebula config: %w", err)
	}

	c.pmux.Restart("nebula")
	return nil
}

// Shutdown blocks until all child processes have gracefully shut themselves
// down.
//
// If this returns an error then it's possible that child processes are
// still running and are no longer managed.
func (c *Children) Shutdown() error {
	c.pmux.Stop()
	return nil
}