package postgres

import (
	"context"
	"encoding/json"
	"fmt"
	"time"
)

type EventRow struct {
	EventID string          `json:"event_id"`
	TS      time.Time       `json:"ts"`
	Type    string          `json:"type"`
	Payload json.RawMessage `json:"payload"`
}

type EventsFilter struct {
	Limit     int
	EventType string
	Framework string
	ClientID  string
	Since     *time.Time // if nil, defaults to 24h ago
}

func (d *DB) ListRecentEvents(ctx context.Context, f EventsFilter) ([]EventRow, error) {
	if f.Limit <= 0 {
		f.Limit = 100
	}
	if f.Limit > 1000 {
		f.Limit = 1000
	}

	since := f.Since
	if since == nil {
		t := time.Now().Add(-24 * time.Hour)
		since = &t
	}

	query := "SELECT event_id, ts, type, payload FROM events WHERE 1=1"
	args := []any{}
	argN := 1

	query += fmt.Sprintf(" AND ts >= $%d", argN)
	args = append(args, *since)
	argN++

	if f.EventType != "" {
		query += fmt.Sprintf(" AND type = $%d", argN)
		args = append(args, f.EventType)
		argN++
	}
	if f.Framework != "" {
		query += fmt.Sprintf(" AND source_framework = $%d", argN)
		args = append(args, f.Framework)
		argN++
	}
	if f.ClientID != "" {
		query += fmt.Sprintf(" AND client_id = $%d", argN)
		args = append(args, f.ClientID)
		argN++
	}

	query += fmt.Sprintf(" ORDER BY ts DESC LIMIT $%d", argN)
	args = append(args, f.Limit)

	rows, err := d.sql.QueryContext(ctx, query, args...)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var out []EventRow
	for rows.Next() {
		var r EventRow
		if err := rows.Scan(&r.EventID, &r.TS, &r.Type, &r.Payload); err != nil {
			return nil, err
		}
		out = append(out, r)
	}
	return out, rows.Err()
}

func (d *DB) ListAgentLiveEvents(ctx context.Context, framework, clientID string, limit int) ([]EventRow, error) {
	if limit <= 0 {
		limit = 200
	}
	if limit > 1000 {
		limit = 1000
	}

	rows, err := d.sql.QueryContext(ctx, `
		SELECT event_id, ts, type, payload
		FROM events
		WHERE source_framework = $1
		  AND client_id = $2
		  AND type IN ('session.start', 'session.end', 'run.start', 'run.end', 'span.start', 'span.end', 'error')
		ORDER BY ts DESC
		LIMIT $3
	`, framework, clientID, limit)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var out []EventRow
	for rows.Next() {
		var r EventRow
		if err := rows.Scan(&r.EventID, &r.TS, &r.Type, &r.Payload); err != nil {
			return nil, err
		}
		out = append(out, r)
	}
	return out, rows.Err()
}