package court

import (
	"context"
	"database/sql"
	"encoding/json"
	"fmt"
	"net/http"
	"time"
)

// SeerHub broadcasts court and LOTL events over SSE.
type SeerHub struct {
	DB *sql.DB
}

func NewSeerHub(db *sql.DB) *SeerHub {
	return &SeerHub{DB: db}
}

// SeerEvent is one SSE payload line.
type SeerEvent struct {
	ID        string          `json:"id"`
	HostID    string          `json:"host_id,omitempty"`
	EventType string          `json:"event_type"`
	Payload   json.RawMessage `json:"payload"`
	CreatedAt time.Time       `json:"created_at"`
}

// StreamHandler serves GET /seer as Server-Sent Events.
func (h *SeerHub) StreamHandler() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		flusher, ok := w.(http.Flusher)
		if !ok {
			http.Error(w, "streaming unsupported", http.StatusInternalServerError)
			return
		}

		w.Header().Set("Content-Type", "text/event-stream")
		w.Header().Set("Cache-Control", "no-cache")
		w.Header().Set("Connection", "keep-alive")

		since := r.URL.Query().Get("since")
		ticker := time.NewTicker(2 * time.Second)
		defer ticker.Stop()

		for {
			select {
			case <-r.Context().Done():
				return
			case <-ticker.C:
				events, err := h.fetchEvents(r.Context(), since)
				if err != nil {
					fmt.Fprintf(w, "event: error\ndata: %q\n\n", err.Error())
					flusher.Flush()
					continue
				}
				for _, ev := range events {
					b, _ := json.Marshal(ev)
					fmt.Fprintf(w, "event: seer\ndata: %s\n\n", b)
					since = ev.CreatedAt.Format("2006-01-02 15:04:05")
				}
				flusher.Flush()
			}
		}
	}
}

func (h *SeerHub) fetchEvents(ctx context.Context, since string) ([]SeerEvent, error) {
	q := `SELECT id, COALESCE(host_id,''), event_type, payload_json, created_at FROM seer_events`
	var rows *sql.Rows
	var err error
	if since != "" {
		rows, err = h.DB.QueryContext(ctx, q+` WHERE created_at > ? ORDER BY created_at ASC LIMIT 50`, since)
	} else {
		rows, err = h.DB.QueryContext(ctx, q+` ORDER BY created_at DESC LIMIT 20`)
	}
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var events []SeerEvent
	for rows.Next() {
		var ev SeerEvent
		var created string
		var payload string
		if err := rows.Scan(&ev.ID, &ev.HostID, &ev.EventType, &payload, &created); err != nil {
			return nil, err
		}
		ev.Payload = json.RawMessage(payload)
		ev.CreatedAt, _ = time.Parse("2006-01-02 15:04:05", created)
		events = append(events, ev)
	}
	return events, rows.Err()
}

// TimelineHandler serves LOTL timeline merged with court events for a host.
func TimelineHandler(c *Court) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		hostID := r.PathValue("id")
		if hostID == "" {
			http.Error(w, "host_id required", http.StatusBadRequest)
			return
		}

		type entry struct {
			Kind      string      `json:"kind"`
			Timestamp time.Time   `json:"timestamp"`
			Data      interface{} `json:"data"`
		}

		var timeline []entry

		if c.Fleet != nil {
			lotl, err := c.Fleet.ListLOTL(r.Context(), hostID, 100)
			if err != nil {
				http.Error(w, err.Error(), http.StatusInternalServerError)
				return
			}
			for _, a := range lotl {
				timeline = append(timeline, entry{Kind: "lotl", Timestamp: a.CreatedAt, Data: a})
			}
		}

		rows, err := c.DB.QueryContext(r.Context(), `
			SELECT id, status, COALESCE(verdict,''), created_at, COALESCE(resolved_at,'')
			FROM court_sessions WHERE host_id = ? ORDER BY created_at DESC LIMIT 20`, hostID)
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
		defer rows.Close()
		for rows.Next() {
			var id, status, verdict, created, resolved string
			if err := rows.Scan(&id, &status, &verdict, &created, &resolved); err != nil {
				http.Error(w, err.Error(), http.StatusInternalServerError)
				return
			}
			ts, _ := time.Parse("2006-01-02 15:04:05", created)
			timeline = append(timeline, entry{
				Kind: "court", Timestamp: ts,
				Data: map[string]string{"session_id": id, "status": status, "verdict": verdict},
			})
		}

		w.Header().Set("Content-Type", "application/json")
		_ = json.NewEncoder(w).Encode(map[string]interface{}{
			"host_id":  hostID,
			"timeline": timeline,
		})
	}
}