package handlers

import (
	"net/http"
	"time"

	"github.com/Fimeg/RedFlag/aggregator-server/internal/database/queries"
	"github.com/gin-gonic/gin"
)

// StatsHandler handles statistics for the dashboard
type StatsHandler struct {
	agentQueries  *queries.AgentQueries
	updateQueries *queries.UpdateQueries
}

// NewStatsHandler creates a new stats handler
func NewStatsHandler(agentQueries *queries.AgentQueries, updateQueries *queries.UpdateQueries) *StatsHandler {
	return &StatsHandler{
		agentQueries:  agentQueries,
		updateQueries: updateQueries,
	}
}

// DashboardStats represents dashboard statistics
type DashboardStats struct {
	TotalAgents      int            `json:"total_agents"`
	OnlineAgents     int            `json:"online_agents"`
	OfflineAgents    int            `json:"offline_agents"`
	PendingUpdates   int            `json:"pending_updates"`
	FailedUpdates    int            `json:"failed_updates"`
	CriticalUpdates  int            `json:"critical_updates"`
	ImportantUpdates int            `json:"high_updates"`
	ModerateUpdates  int            `json:"medium_updates"`
	LowUpdates       int            `json:"low_updates"`
	UpdatesByType    map[string]int `json:"updates_by_type"`
}

// GetDashboardStats returns dashboard statistics using aggregate queries (F-B1-6 fix)
func (h *StatsHandler) GetDashboardStats(c *gin.Context) {
	// Get all agents for online/offline count
	agents, err := h.agentQueries.ListAgents("", "")
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to get agents"})
		return
	}

	stats := DashboardStats{
		TotalAgents:   len(agents),
		UpdatesByType: make(map[string]int),
	}

	// Count online/offline agents
	for _, agent := range agents {
		if time.Since(agent.LastSeen) <= 10*time.Minute {
			stats.OnlineAgents++
		} else {
			stats.OfflineAgents++
		}
	}

	// Single aggregate query for all update stats (replaces N+1 per-agent loop)
	updateStats, err := h.updateQueries.GetAllUpdateStats()
	if err == nil {
		stats.PendingUpdates = updateStats.PendingUpdates
		stats.FailedUpdates = updateStats.FailedUpdates
		stats.CriticalUpdates = updateStats.CriticalUpdates
		stats.ImportantUpdates = updateStats.ImportantUpdates
		stats.ModerateUpdates = updateStats.ModerateUpdates
		stats.LowUpdates = updateStats.LowUpdates
	}

	c.JSON(http.StatusOK, stats)
}