package daemon

import (
	"context"
	"errors"
	"fmt"
	"io/fs"
	"isle/bootstrap"
	"isle/daemon/daecommon"
	"isle/daemon/network"
	"os"
	"path/filepath"
	"slices"
	"strings"
	"sync"
)

func getDefaultHTTPSocketDirPath() string {
	path, err := firstExistingDir(
		"/tmp",
		"/run",
		"/var/run",
		"/dev/shm",
	)
	if err != nil {
		panic(fmt.Sprintf("Failed to find directory for HTTP socket: %v", err))
	}

	return path
}

// HTTPSocketPath returns the path to the daemon's HTTP socket which is used for
// RPC and other functionality.
var HTTPSocketPath = sync.OnceValue(func() string {
	return envOr(
		"ISLE_DAEMON_HTTP_SOCKET_PATH",
		func() string {
			return filepath.Join(
				getDefaultHTTPSocketDirPath(), "isle-daemon.sock",
			)
		},
	)
})

func pickNetworkConfig(
	networkConfigs map[string]daecommon.NetworkConfig,
	creationParams bootstrap.CreationParams,
) *daecommon.NetworkConfig {
	if len(networkConfigs) == 1 { // DEPRECATED
		if c, ok := networkConfigs[daecommon.DeprecatedNetworkID]; ok {
			return &c
		}
	}

	for searchStr, networkConfig := range networkConfigs {
		if creationParams.Matches(searchStr) {
			return &networkConfig
		}
	}

	return nil
}

func validateConfig(
	ctx context.Context,
	networkLoader network.Loader,
	daemonConfig daecommon.Config,
	loadableNetworks []bootstrap.CreationParams,
) error {
	givenConfigs := daemonConfig.Networks
	daemonConfig.Networks = map[string]daecommon.NetworkConfig{}

	for _, creationParams := range loadableNetworks {
		id := creationParams.ID

		if c := pickNetworkConfig(givenConfigs, creationParams); c != nil {
			daemonConfig.Networks[id] = *c
			continue
		}

		c, err := networkLoader.StoredConfig(ctx, id)
		if err != nil {
			return fmt.Errorf("getting stored config for %q: %w", id, err)
		}

		daemonConfig.Networks[id] = c
	}

	return daemonConfig.Validate()
}

////////////////////////////////////////////////////////////////////////////////
// Jigs

func envOr(name string, fallback func() string) string {
	if v := os.Getenv(name); v != "" {
		return v
	}
	return fallback()
}

func firstExistingDir(paths ...string) (string, error) {
	var errs []error
	for _, path := range paths {
		stat, err := os.Stat(path)
		switch {
		case errors.Is(err, fs.ErrExist):
			continue
		case err != nil:
			errs = append(
				errs, fmt.Errorf("checking if path %q exists: %w", path, err),
			)
		case !stat.IsDir():
			errs = append(
				errs, fmt.Errorf("path %q exists but is not a directory", path),
			)
		default:
			return path, nil
		}
	}

	err := fmt.Errorf(
		"no directory found at any of the following paths: %s",
		strings.Join(paths, ", "),
	)
	if len(errs) > 0 {
		err = errors.Join(slices.Insert(errs, 0, err)...)
	}
	return "", err
}