package app

import (
	"encoding/json"
	"os"
	"path/filepath"
	"time"
)

var (
	transportPolicyRuntimeStatePath = transportPolicyRuntimePath
	transportPolicyRuntimeSnapPath  = transportPolicyRuntimeSnap
)

type transportPolicyRuntimeState struct {
	Version        int                               `json:"version"`
	UpdatedAt      string                            `json:"updated_at,omitempty"`
	PolicyRevision int64                             `json:"policy_revision,omitempty"`
	ApplyID        string                            `json:"apply_id,omitempty"`
	InterfaceCount int                               `json:"interface_count"`
	RuleCount      int                               `json:"rule_count"`
	Interfaces     []TransportPolicyCompileInterface `json:"interfaces,omitempty"`
}

func loadTransportPolicyRuntimeState() transportPolicyRuntimeState {
	st := transportPolicyRuntimeState{Version: transportStateVersion}
	data, err := os.ReadFile(transportPolicyRuntimeStatePath)
	if err != nil {
		return st
	}
	if err := json.Unmarshal(data, &st); err != nil {
		return transportPolicyRuntimeState{Version: transportStateVersion}
	}
	if st.Version == 0 {
		st.Version = transportStateVersion
	}
	if st.Interfaces == nil {
		st.Interfaces = nil
	}
	return st
}

func saveTransportPolicyRuntimeState(st transportPolicyRuntimeState) error {
	st.Version = transportStateVersion
	st.UpdatedAt = time.Now().UTC().Format(time.RFC3339)
	data, err := json.MarshalIndent(st, "", "  ")
	if err != nil {
		return err
	}
	if err := os.MkdirAll(filepath.Dir(transportPolicyRuntimeStatePath), 0o755); err != nil {
		return err
	}
	tmp := transportPolicyRuntimeStatePath + ".tmp"
	if err := os.WriteFile(tmp, data, 0o644); err != nil {
		return err
	}
	return os.Rename(tmp, transportPolicyRuntimeStatePath)
}

func saveTransportPolicyRuntimeSnapshot(st transportPolicyRuntimeState) error {
	data, err := json.MarshalIndent(st, "", "  ")
	if err != nil {
		return err
	}
	if err := os.MkdirAll(filepath.Dir(transportPolicyRuntimeSnapPath), 0o755); err != nil {
		return err
	}
	tmp := transportPolicyRuntimeSnapPath + ".tmp"
	if err := os.WriteFile(tmp, data, 0o644); err != nil {
		return err
	}
	return os.Rename(tmp, transportPolicyRuntimeSnapPath)
}

func loadTransportPolicyRuntimeSnapshot() (transportPolicyRuntimeState, bool) {
	data, err := os.ReadFile(transportPolicyRuntimeSnapPath)
	if err != nil {
		return transportPolicyRuntimeState{}, false
	}
	var st transportPolicyRuntimeState
	if err := json.Unmarshal(data, &st); err != nil {
		return transportPolicyRuntimeState{}, false
	}
	if st.Version == 0 {
		st.Version = transportStateVersion
	}
	if st.Interfaces == nil {
		st.Interfaces = nil
	}
	return st, true
}