package handler

import (
	"net/http"
	"time"

	"github.com/gin-gonic/gin"
	"github.com/jackc/pgx/v5/pgxpool"
)

type DashboardHandler struct {
	Pool *pgxpool.Pool
}

type DashboardStats struct {
	TotalArtifacts   int `json:"total_artifacts"`
	TotalRepos       int `json:"total_repos"`
	TotalCrashGroups int `json:"total_crash_groups"`
	OpenCrashGroups  int `json:"open_crash_groups"`
	ActiveCampaigns  int `json:"active_campaigns"`
}

type TrendPoint struct {
	Date  string `json:"date"`
	Count int    `json:"count"`
}

type TopCrasher struct {
	Title           string `json:"title"`
	OccurrenceCount int    `json:"occurrence_count"`
	RepoName        string `json:"repo_name"`
	CrashGroupID    string `json:"crash_group_id"`
}

type DashboardResponse struct {
	Stats       DashboardStats `json:"stats"`
	Trend       []TrendPoint   `json:"trend"`
	TopCrashers []TopCrasher   `json:"top_crashers"`
}

func (h *DashboardHandler) Stats(c *gin.Context) {
	ctx := c.Request.Context()
	var stats DashboardStats

	_ = h.Pool.QueryRow(ctx, "SELECT COUNT(*) FROM artifacts").Scan(&stats.TotalArtifacts)
	_ = h.Pool.QueryRow(ctx, "SELECT COUNT(*) FROM repositories").Scan(&stats.TotalRepos)
	_ = h.Pool.QueryRow(ctx, "SELECT COUNT(*) FROM crash_groups").Scan(&stats.TotalCrashGroups)
	_ = h.Pool.QueryRow(ctx, "SELECT COUNT(*) FROM crash_groups WHERE status = 'open'").Scan(&stats.OpenCrashGroups)
	_ = h.Pool.QueryRow(ctx, "SELECT COUNT(*) FROM campaigns WHERE status = 'running'").Scan(&stats.ActiveCampaigns)

	// Artifact trend for the last 30 days.
	var trend []TrendPoint
	rows, err := h.Pool.Query(ctx, `
		SELECT DATE(created_at) as day, COUNT(*)
		FROM artifacts
		WHERE created_at >= $1
		GROUP BY day
		ORDER BY day
	`, time.Now().AddDate(0, 0, -30))
	if err == nil {
		defer rows.Close()
		for rows.Next() {
			var tp TrendPoint
			var d time.Time
			if rows.Scan(&d, &tp.Count) == nil {
				tp.Date = d.Format("2006-01-02")
				trend = append(trend, tp)
			}
		}
	}

	// Top crashers (most frequent open crash groups).
	var topCrashers []TopCrasher
	rows2, err := h.Pool.Query(ctx, `
		SELECT cg.id, cg.title, cs.occurrence_count, r.name
		FROM crash_groups cg
		JOIN crash_signatures cs ON cs.id = cg.crash_signature_id
		JOIN repositories r ON r.id = cg.repository_id
		WHERE cg.status = 'open'
		ORDER BY cs.occurrence_count DESC
		LIMIT 10
	`)
	if err == nil {
		defer rows2.Close()
		for rows2.Next() {
			var tc TopCrasher
			if rows2.Scan(&tc.CrashGroupID, &tc.Title, &tc.OccurrenceCount, &tc.RepoName) == nil {
				topCrashers = append(topCrashers, tc)
			}
		}
	}

	c.JSON(http.StatusOK, DashboardResponse{
		Stats:       stats,
		Trend:       trend,
		TopCrashers: topCrashers,
	})
}