package repository

import (
	"context"
	"fmt"
	"time"

	"github.com/prabhupadasays/spsays-bff/internal/model"
)

// ListShortURLs returns a page of shortened URLs filtered by an optional query
// (matched against code or target URL), newest first, with the total count.
func (r *AdminRepo) ListShortURLs(ctx context.Context, q string, limit, offset int) ([]model.AdminShortURL, int, error) {
	limit = clampLimit(limit)
	rows, err := r.pg.Pool.Query(ctx, `
		SELECT id, code, long_url, content_type, click_count, human_click_count,
		       disabled, created_at,
		       COUNT(*) OVER() AS total
		FROM shortened_urls
		WHERE ($1 = '' OR code ILIKE '%'||$1||'%' OR long_url ILIKE '%'||$1||'%')
		ORDER BY created_at DESC
		LIMIT $2 OFFSET $3`, q, limit, offset)
	if err != nil {
		return nil, 0, fmt.Errorf("admin list short urls: %w", err)
	}
	defer rows.Close()

	out := []model.AdminShortURL{}
	total := 0
	for rows.Next() {
		var s model.AdminShortURL
		if err := rows.Scan(&s.ID, &s.Code, &s.LongURL, &s.ContentType,
			&s.ClickCount, &s.HumanClickCount, &s.Disabled, &s.CreatedAt, &total); err != nil {
			return nil, 0, fmt.Errorf("scan admin short url: %w", err)
		}
		out = append(out, s)
	}
	return out, total, rows.Err()
}

// ShortURLStats computes created + click counts for the three fixed windows
// (thresholds passed in), the all-time totals, and — when from/to is given —
// a custom range (from inclusive, to exclusive). "Created" comes from
// shortened_urls.created_at; "clicks" from the shortened_url_clicks log.
func (r *AdminRepo) ShortURLStats(
	ctx context.Context,
	todayStart, weekStart, monthStart time.Time,
	from, to *time.Time,
) (*model.ShortURLStats, error) {
	var s model.ShortURLStats

	if err := r.pg.Pool.QueryRow(ctx, `
		SELECT COUNT(*),
		       COUNT(*) FILTER (WHERE created_at >= $1),
		       COUNT(*) FILTER (WHERE created_at >= $2),
		       COUNT(*) FILTER (WHERE created_at >= $3)
		FROM shortened_urls`, todayStart, weekStart, monthStart).
		Scan(&s.TotalURLs, &s.Today.Created, &s.Week.Created, &s.Month.Created); err != nil {
		return nil, fmt.Errorf("short url created stats: %w", err)
	}

	if err := r.pg.Pool.QueryRow(ctx, `
		SELECT COUNT(*),
		       COUNT(*) FILTER (WHERE clicked_at >= $1),
		       COUNT(*) FILTER (WHERE clicked_at >= $2),
		       COUNT(*) FILTER (WHERE clicked_at >= $3)
		FROM shortened_url_clicks`, todayStart, weekStart, monthStart).
		Scan(&s.TotalClicks, &s.Today.Clicks, &s.Week.Clicks, &s.Month.Clicks); err != nil {
		return nil, fmt.Errorf("short url click stats: %w", err)
	}

	if from != nil && to != nil {
		var rng model.ShortURLRangeStat
		if err := r.pg.Pool.QueryRow(ctx,
			`SELECT COUNT(*) FROM shortened_urls WHERE created_at >= $1 AND created_at < $2`,
			*from, *to).Scan(&rng.Created); err != nil {
			return nil, fmt.Errorf("short url range created: %w", err)
		}
		if err := r.pg.Pool.QueryRow(ctx,
			`SELECT COUNT(*) FROM shortened_url_clicks WHERE clicked_at >= $1 AND clicked_at < $2`,
			*from, *to).Scan(&rng.Clicks); err != nil {
			return nil, fmt.Errorf("short url range clicks: %w", err)
		}
		s.Range = &rng
	}

	return &s, nil
}