package nodeconfig

import (
	"fmt"
	"io/fs"
	"os"
	"strconv"
	"time"

	"git.frostfs.info/TrueCloudLab/frostfs-node/cmd/frostfs-node/config"
	"git.frostfs.info/TrueCloudLab/frostfs-node/pkg/network"
	utilConfig "git.frostfs.info/TrueCloudLab/frostfs-node/pkg/util/config"
	"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
)

// PersistentSessionsConfig is a wrapper over "persistent_sessions" config section
// which provides access to persistent session tokens storage configuration of node.
type PersistentSessionsConfig struct {
	cfg *config.Config
}

// PersistentStateConfig is a wrapper over "persistent_state" config section
// which provides access to persistent state storage configuration of node.
type PersistentStateConfig struct {
	cfg *config.Config
}

// NotificationConfig is a wrapper over "notification" config section
// which provides access to object notification configuration of node.
type NotificationConfig struct {
	cfg *config.Config
}

// PersistentPolicyRulesConfig is a wrapper over "persistent_policy_rules" config section
// which provides access to persistent policy rules storage configuration of node.
type PersistentPolicyRulesConfig struct {
	cfg *config.Config
}

const (
	subsection                      = "node"
	persistentSessionsSubsection    = "persistent_sessions"
	persistentStateSubsection       = "persistent_state"
	notificationSubsection          = "notification"
	persistentPolicyRulesSubsection = "persistent_policy_rules"

	attributePrefix = "attribute"

	// PersistentStatePathDefault is a default path for persistent state file.
	PersistentStatePathDefault = ".frostfs-storage-state"

	// NotificationTimeoutDefault is a default timeout for object notification operation.
	NotificationTimeoutDefault = 5 * time.Second
)

// Key returns the  value of "key" config parameter
// from "node" section.
//
// If the  value is not set, fallbacks to Wallet section.
//
// Panics if the  value is incorrect filename of binary encoded private key.
func Key(c *config.Config) *keys.PrivateKey {
	v := config.StringSafe(c.Sub(subsection), "key")
	if v == "" {
		return Wallet(c)
	}

	var (
		key  *keys.PrivateKey
		err  error
		data []byte
	)
	if data, err = os.ReadFile(v); err == nil {
		key, err = keys.NewPrivateKeyFromBytes(data)
	}

	if err != nil {
		panic(fmt.Errorf("invalid private key in node section: %w", err))
	}

	return key
}

// Wallet returns the value of a node private key from "node" section.
//
// Panics if section contains invalid values.
func Wallet(c *config.Config) *keys.PrivateKey {
	v := c.Sub(subsection).Sub("wallet")
	acc, err := utilConfig.LoadAccount(
		config.String(v, "path"),
		config.String(v, "address"),
		config.String(v, "password"))
	if err != nil {
		panic(fmt.Errorf("invalid wallet config: %w", err))
	}

	return acc.PrivateKey()
}

type stringAddressGroup []string

func (x stringAddressGroup) IterateAddresses(f func(string) bool) {
	for i := range x {
		if f(x[i]) {
			break
		}
	}
}

func (x stringAddressGroup) NumberOfAddresses() int {
	return len(x)
}

// BootstrapAddresses returns the value of "addresses" config parameter
// from "node" section as network.AddressGroup.
//
// Panics if the value is not a string list of valid NeoFS network addresses.
func BootstrapAddresses(c *config.Config) (addr network.AddressGroup) {
	v := config.StringSlice(c.Sub(subsection), "addresses")

	err := addr.FromIterator(stringAddressGroup(v))
	if err != nil {
		panic(fmt.Errorf("could not parse bootstrap addresses: %w", err))
	}

	return addr
}

// Attributes returns list of config parameters
// from "node" section that are set in "attribute_i" format,
// where i in range [0,100).
func Attributes(c *config.Config) (attrs []string) {
	const maxAttributes = 100

	for i := 0; i < maxAttributes; i++ {
		attr := config.StringSafe(c.Sub(subsection), attributePrefix+"_"+strconv.Itoa(i))
		if attr == "" {
			return
		}

		attrs = append(attrs, attr)
	}

	return
}

// Relay returns the value of "relay" config parameter
// from "node" section.
//
// Returns false if the value is not set.
func Relay(c *config.Config) bool {
	return config.BoolSafe(c.Sub(subsection), "relay")
}

// PersistentSessions returns structure that provides access to "persistent_sessions"
// subsection of "node" section.
func PersistentSessions(c *config.Config) PersistentSessionsConfig {
	return PersistentSessionsConfig{
		c.Sub(subsection).Sub(persistentSessionsSubsection),
	}
}

// Path returns the value of "path" config parameter.
func (p PersistentSessionsConfig) Path() string {
	return config.String(p.cfg, "path")
}

// PersistentState returns structure that provides access to "persistent_state"
// subsection of "node" section.
func PersistentState(c *config.Config) PersistentStateConfig {
	return PersistentStateConfig{
		c.Sub(subsection).Sub(persistentStateSubsection),
	}
}

// Path returns the value of "path" config parameter.
//
// Returns PersistentStatePathDefault if the value is not a non-empty string.
func (p PersistentStateConfig) Path() string {
	v := config.String(p.cfg, "path")
	if v != "" {
		return v
	}

	return PersistentStatePathDefault
}

// Notification returns structure that provides access to "notification"
// subsection of "node" section.
func Notification(c *config.Config) NotificationConfig {
	return NotificationConfig{
		c.Sub(subsection).Sub(notificationSubsection),
	}
}

// Enabled returns the value of "enabled" config parameter from "notification"
// subsection of "node" section.
//
// Returns false if the value is not presented.
func (n NotificationConfig) Enabled() bool {
	return config.BoolSafe(n.cfg, "enabled")
}

// DefaultTopic returns the value of "default_topic" config parameter from
// "notification" subsection of "node" section.
//
// Returns empty string if the value is not presented.
func (n NotificationConfig) DefaultTopic() string {
	return config.StringSafe(n.cfg, "default_topic")
}

// Endpoint returns the value of "endpoint" config parameter from "notification"
// subsection of "node" section.
//
// Returns empty string if the value is not presented.
func (n NotificationConfig) Endpoint() string {
	return config.StringSafe(n.cfg, "endpoint")
}

// Timeout returns the value of "timeout" config parameter from "notification"
// subsection of "node" section.
//
// Returns NotificationTimeoutDefault if the value is not positive.
func (n NotificationConfig) Timeout() time.Duration {
	v := config.DurationSafe(n.cfg, "timeout")
	if v > 0 {
		return v
	}

	return NotificationTimeoutDefault
}

// CertPath returns the value of "certificate_path" config parameter from "notification"
// subsection of "node" section.
//
// Returns empty string if the value is not presented.
func (n NotificationConfig) CertPath() string {
	return config.StringSafe(n.cfg, "certificate")
}

// KeyPath returns the value of "key_path" config parameter from
// "notification" subsection of "node" section.
//
// Returns empty string if the value is not presented.
func (n NotificationConfig) KeyPath() string {
	return config.StringSafe(n.cfg, "key")
}

// CAPath returns the value of "ca_path" config parameter from
// "notification" subsection of "node" section.
//
// Returns empty string if the value is not presented.
func (n NotificationConfig) CAPath() string {
	return config.StringSafe(n.cfg, "ca")
}

const (
	// PermDefault is a default permission bits for local override storage file.
	PermDefault = 0o644
)

// PersistentPolicyRules returns structure that provides access to "persistent_policy_rules"
// subsection of "node" section.
func PersistentPolicyRules(c *config.Config) PersistentPolicyRulesConfig {
	return PersistentPolicyRulesConfig{
		c.Sub(subsection).Sub(persistentPolicyRulesSubsection),
	}
}

// Path returns the value of "path" config parameter.
//
// Returns empty string if missing, for compatibility with older configurations.
func (l PersistentPolicyRulesConfig) Path() string {
	return config.StringSafe(l.cfg, "path")
}

// Perm returns the value of "perm" config parameter as a fs.FileMode.
//
// Returns PermDefault if the value is not a positive number.
func (l PersistentPolicyRulesConfig) Perm() fs.FileMode {
	p := config.UintSafe((*config.Config)(l.cfg), "perm")
	if p == 0 {
		p = PermDefault
	}

	return fs.FileMode(p)
}

// NoSync returns the value of "no_sync" config parameter as a bool value.
//
// Returns false if the value is not a boolean.
func (l PersistentPolicyRulesConfig) NoSync() bool {
	return config.BoolSafe((*config.Config)(l.cfg), "no_sync")
}

// CompatibilityMode returns true if need to run node in compatibility with previous versions mode.
func CompatibilityMode(c *config.Config) bool {
	return config.BoolSafe(c.Sub(subsection), "kludge_compatibility_mode")
}