// SPDX-License-Identifier: Apache-2.0

package main

import "encoding/json"

// StateSnapshot is the full JSON snapshot served for a single maglevd.
type StateSnapshot struct {
	Maglevd      MaglevdInfo            `json:"maglevd"`
	Frontends    []*FrontendSnapshot    `json:"frontends"`
	Backends     []*BackendSnapshot     `json:"backends"`
	HealthChecks []*HealthCheckSnapshot `json:"healthchecks"`
	VPPInfo      *VPPInfoSnapshot       `json:"vpp_info,omitempty"`
	// VPPState is "connected", "disconnected", or "" (unknown). Updated
	// from vpp-connect / vpp-disconnect / vpp-api-{send,recv} log
	// events and re-seeded on every refreshAll tick.
	VPPState string `json:"vpp_state,omitempty"`
	// LBState is the most recent VPP LB plugin view of buckets-per-backend,
	// keyed by frontend name → backend name → bucket count. nil when VPP is
	// disconnected or no fetch has succeeded yet.
	LBState *LBStateSnapshot `json:"lb_state,omitempty"`
}

// LBStateSnapshot is a per-(frontend, backend) view of VPP's bucket
// allocation. The frontend collects this with GetVPPLBState and matches
// VPP's VIP records back to maglev frontend/backend names so the SPA
// never has to know about VPP-side prefixes or AS addresses.
type LBStateSnapshot struct {
	PerFrontend map[string]map[string]int32 `json:"per_frontend"`
}

// MaglevdInfo is the per-maglevd connection status record.
type MaglevdInfo struct {
	Name      string `json:"name"`
	Address   string `json:"address"`
	Connected bool   `json:"connected"`
	LastError string `json:"last_error,omitempty"`
}

// VersionInfo is the build metadata of this maglevd-frontend binary
// plus runtime capability flags the SPA needs to know at mount time.
type VersionInfo struct {
	Version      string `json:"version"`
	Commit       string `json:"commit"`
	Date         string `json:"date"`
	AdminEnabled bool   `json:"admin_enabled"`
}

type FrontendSnapshot struct {
	Name        string          `json:"name"`
	Address     string          `json:"address"`
	Protocol    string          `json:"protocol"`
	Port        uint32          `json:"port"`
	Description string          `json:"description,omitempty"`
	SrcIPSticky bool            `json:"src_ip_sticky"`
	Pools       []*PoolSnapshot `json:"pools"`
	// State is the aggregated frontend state ("up" | "down" | "unknown")
	// populated from FrontendEvent messages, including the synthetic
	// from==to replay that maglevd sends on WatchEvents subscribe.
	State string `json:"state,omitempty"`
}

type PoolSnapshot struct {
	Name     string                 `json:"name"`
	Backends []*PoolBackendSnapshot `json:"backends"`
}

type PoolBackendSnapshot struct {
	Name            string `json:"name"`
	Weight          int32  `json:"weight"`
	EffectiveWeight int32  `json:"effective_weight"`
}

type BackendSnapshot struct {
	Name           string              `json:"name"`
	Address        string              `json:"address"`
	State          string              `json:"state"`
	Enabled        bool                `json:"enabled"`
	HealthCheck    string              `json:"healthcheck"`
	LastTransition *TransitionRecord   `json:"last_transition,omitempty"`
	Transitions    []*TransitionRecord `json:"transitions,omitempty"`
}

type TransitionRecord struct {
	From     string `json:"from"`
	To       string `json:"to"`
	AtUnixNs int64  `json:"at_unix_ns"`
}

type HealthCheckSnapshot struct {
	Name           string `json:"name"`
	Type           string `json:"type"`
	Port           uint32 `json:"port"`
	IntervalNs     int64  `json:"interval_ns"`
	FastIntervalNs int64  `json:"fast_interval_ns"`
	DownIntervalNs int64  `json:"down_interval_ns"`
	TimeoutNs      int64  `json:"timeout_ns"`
	Rise           int32  `json:"rise"`
	Fall           int32  `json:"fall"`
}

type VPPInfoSnapshot struct {
	Version       string `json:"version"`
	BuildDate     string `json:"build_date"`
	PID           uint32 `json:"pid"`
	BoottimeNs    int64  `json:"boottime_ns"`
	ConnecttimeNs int64  `json:"connecttime_ns"`
}

// BrowserEvent is the wire shape sent over SSE to the browser.
type BrowserEvent struct {
	Maglevd  string          `json:"maglevd"`
	Type     string          `json:"type"` // log|backend|frontend|maglevd-status|vpp-status|lb-state|resync
	AtUnixNs int64           `json:"at_unix_ns"`
	Payload  json.RawMessage `json:"payload"`
}

// LBStatePayload rides on a "lb-state" BrowserEvent and carries the
// freshly-fetched bucket map. PerFrontend may be nil (or empty) to
// signal "no LB state available" — the SPA renders such backends
// with an em-dash in the buckets column.
type LBStatePayload struct {
	PerFrontend map[string]map[string]int32 `json:"per_frontend"`
}

// BackendEventPayload is what we ship inside BrowserEvent.Payload for
// type == "backend".
type BackendEventPayload struct {
	Backend    string           `json:"backend"`
	Transition TransitionRecord `json:"transition"`
}

type FrontendEventPayload struct {
	Frontend   string           `json:"frontend"`
	Transition TransitionRecord `json:"transition"`
}

type LogEventPayload struct {
	Level string            `json:"level"`
	Msg   string            `json:"msg"`
	Attrs map[string]string `json:"attrs,omitempty"`
}

type MaglevdStatusPayload struct {
	Connected bool   `json:"connected"`
	LastError string `json:"last_error,omitempty"`
}

// VPPStatusPayload rides on a "vpp-status" BrowserEvent and tells the
// SPA when the maglevd↔VPP connection flips. Emitted by the frontend's
// log-event handler on vpp-connect / vpp-disconnect, and on the first
// sighting of vpp-api-send/recv (which implies VPP is up).
type VPPStatusPayload struct {
	State string `json:"state"` // "connected" | "disconnected"
}