package service

import (
	"encoding/json"

	"github.com/mhsanaei/3x-ui/v3/internal/database"
	"github.com/mhsanaei/3x-ui/v3/internal/database/model"
	"github.com/mhsanaei/3x-ui/v3/internal/logger"
	"github.com/mhsanaei/3x-ui/v3/internal/singbox"
)

// RecomputeSingboxFragment re-runs the sing-box converter over an
// inbound row's current panel material and stores the fresh fragment
// + preserved sidecar (V2.0.1 ⓪). Before this, the fragment was a
// one-shot migration snapshot: panel edits after the migration (a new
// Reality target, a changed listen/port, ...) never reached it, so
// the agent kept serving the migration-day material while the panel
// showed the edit as saved. The identity layer is read back after the
// caller's own sync, so the fragment's embedded users match what
// generation would project anyway; the row listen/port override is
// stamped on top exactly as generation applies it.
func (s *SingboxService) RecomputeSingboxFragment(inbound *model.Inbound) error {
	attached, err := s.inboundService.clientService.ListForInbound(nil, inbound.Id)
	if err != nil {
		return err
	}
	clients := toSingboxClients(attached)
	fillConverterOnlyClientFields(inbound, attached, clients)

	fallbackMaps, err := s.inboundService.fallbackService.BuildFallbacksJSON(nil, inbound.Id)
	if err != nil {
		return err
	}
	fallbacks := make([]json.RawMessage, 0, len(fallbackMaps))
	for _, fm := range fallbackMaps {
		raw, err := json.Marshal(fm)
		if err != nil {
			return err
		}
		fallbacks = append(fallbacks, raw)
	}

	res, err := singbox.ConvertInbound(singbox.Inbound{
		Listen:         inbound.Listen,
		Port:           inbound.Port,
		Protocol:       string(inbound.Protocol),
		Tag:            inbound.Tag,
		DisableFlow:    inbound.DisableFlow,
		Settings:       json.RawMessage(inbound.Settings),
		StreamSettings: json.RawMessage(inbound.StreamSettings),
		Sniffing:       json.RawMessage(inbound.Sniffing),
		Fallbacks:      fallbacks,
		Clients:        clients,
	})
	if err != nil {
		return err
	}
	fragJSON, err := res.MarshalFragment()
	if err != nil {
		return err
	}
	if fragJSON != "" {
		fragment := map[string]any{}
		if err := json.Unmarshal([]byte(fragJSON), &fragment); err != nil {
			return err
		}
		applyRowListenOverride(inbound, fragment)
		raw, err := json.Marshal(fragment)
		if err != nil {
			return err
		}
		fragJSON = string(raw)
	}
	presJSON, err := res.MarshalPreserved()
	if err != nil {
		return err
	}
	return database.GetDB().Model(&model.Inbound{}).Where("id = ?", inbound.Id).Updates(map[string]any{
		"singbox_config": fragJSON, "singbox_preserved": presJSON,
	}).Error
}

// fillConverterOnlyClientFields restores the client fields the
// identity projection (toSingboxClients) does not carry but the
// converter reads: VMess alterId lives only in the settings.clients
// mirror (the identity layer has no column for it — the B1 migrator
// sourced it from the same mirror), and a VLESS client's reverse
// block reaches the identity projection as a parsed tag, re-rendered
// here in the converter's verbatim-JSON shape.
func fillConverterOnlyClientFields(inbound *model.Inbound, attached []model.Client, clients []singbox.Client) {
	alterByEmail := map[string]int{}
	var settings struct {
		Clients []struct {
			Email   string `json:"email"`
			AlterID int    `json:"alterId"`
		} `json:"clients"`
	}
	if err := json.Unmarshal([]byte(inbound.Settings), &settings); err == nil {
		for _, c := range settings.Clients {
			if c.AlterID != 0 {
				alterByEmail[c.Email] = c.AlterID
			}
		}
	}
	reverseByEmail := map[string]string{}
	for _, c := range attached {
		if c.Reverse != nil && c.Reverse.Tag != "" {
			reverseByEmail[c.Email] = c.Reverse.Tag
		}
	}
	for i := range clients {
		if alt, ok := alterByEmail[clients[i].Email]; ok {
			clients[i].AlterID = alt
		}
		if tag, ok := reverseByEmail[clients[i].Email]; ok {
			if raw, err := json.Marshal(map[string]string{"tag": tag}); err == nil {
				clients[i].Reverse = raw
			}
		}
	}
}

// recomputeSingboxFragmentLogged is the save-path hook: a failed
// recompute must not fail the panel save itself (the row is already
// persisted and generation still overrides listen/port from it), but
// it is logged loudly — a silent skip here is exactly how the
// V2.0.0 fragment drift stayed invisible.
func recomputeSingboxFragmentLogged(inbound *model.Inbound) {
	svc := &SingboxService{inboundService: InboundService{}}
	if err := svc.RecomputeSingboxFragment(inbound); err != nil {
		logger.Warningf("sing-box fragment recompute for inbound %d (%s) failed: %v", inbound.Id, inbound.Tag, err)
	}
}