package atlas

import (
	"fmt"
	"strings"
)

const (
	FleetGossipHaveShard = "have_shard"
	FleetGossipHealthy   = "healthy"
	FleetGossipKnowNode  = "know_node"
)

type FleetGossipRecord struct {
	Kind          string `json:"kind"`
	AgentID       string `json:"agent_id,omitempty"`
	Subnet        string `json:"subnet,omitempty"`
	Token         string `json:"token,omitempty"`
	ShardIndex    int    `json:"shard_index,omitempty"`
	ShardHash     string `json:"shard_hash,omitempty"`
	Region        string `json:"region,omitempty"`
	ShardAdvert   string `json:"shard_advert,omitempty"`
	TargetAgentID string `json:"target_agent_id,omitempty"`
	Healthy       bool   `json:"healthy,omitempty"`
	FetchURL      string `json:"fetch_url,omitempty"`
}

func NormalizeFleetGossipRecord(r FleetGossipRecord) (FleetGossipRecord, bool) {
	r.Kind = strings.TrimSpace(strings.ToLower(r.Kind))
	r.AgentID = strings.TrimSpace(r.AgentID)
	r.Subnet = strings.TrimSpace(r.Subnet)
	r.Token = strings.TrimSpace(r.Token)
	r.ShardHash = strings.TrimSpace(strings.ToLower(r.ShardHash))
	r.Region = strings.TrimSpace(r.Region)
	r.ShardAdvert = strings.TrimSpace(r.ShardAdvert)
	r.TargetAgentID = strings.TrimSpace(r.TargetAgentID)
	r.FetchURL = strings.TrimSpace(r.FetchURL)
	switch r.Kind {
	case FleetGossipHaveShard:
		if r.AgentID == "" || r.Token == "" || r.ShardHash == "" {
			return FleetGossipRecord{}, false
		}
		if r.Region == "" && r.ShardAdvert != "" {
			if region, idx, ok := parseShardAdvert(r.ShardAdvert); ok {
				r.Region = region
				if r.ShardIndex == 0 {
					r.ShardIndex = idx
				}
			}
		}
		if r.ShardAdvert == "" && r.Region != "" {
			r.ShardAdvert = fmt.Sprintf("%s:%d", r.Region, r.ShardIndex)
		}
	case FleetGossipHealthy:
		if r.AgentID == "" {
			return FleetGossipRecord{}, false
		}
	case FleetGossipKnowNode:
		if r.AgentID == "" || r.TargetAgentID == "" {
			return FleetGossipRecord{}, false
		}
	default:
		return FleetGossipRecord{}, false
	}
	return r, true
}

func NormalizeFleetGossipRecords(in []FleetGossipRecord) []FleetGossipRecord {
	if len(in) == 0 {
		return nil
	}
	out := make([]FleetGossipRecord, 0, len(in))
	for _, r := range in {
		if norm, ok := NormalizeFleetGossipRecord(r); ok {
			out = append(out, norm)
		}
	}
	return out
}

func parseShardAdvert(advert string) (region string, index int, ok bool) {
	colon := strings.LastIndex(strings.TrimSpace(advert), ":")
	if colon <= 0 {
		return "", 0, false
	}
	region = strings.TrimSpace(advert[:colon])
	if _, err := fmt.Sscanf(strings.TrimSpace(advert[colon+1:]), "%d", &index); err != nil {
		return "", 0, false
	}
	return region, index, region != ""
}