package main

import (
	"context"
	"time"

	"github.com/jackc/pgx/v5/pgxpool"
)

type HostRow struct {
	ID               int64
	Hostname         string
	Protocol         string
	HtmlTitle        string
	IframeAllowed    bool
	BestIconHash     string
	RandomOrder      float64
	IconDownloadedAt *time.Time
}

// fetchHostsWithIcons gets hosts with icons, ordered by icon_downloaded_at for disk locality.
func fetchHostsWithIcons(ctx context.Context, pool *pgxpool.Pool, lastDownloaded *time.Time, lastID int64, limit int) ([]HostRow, error) {
	var query string
	var args []any
	if lastDownloaded == nil && lastID == 0 {
		query = `SELECT id, hostname, protocol, html_title, COALESCE(iframe_allowed, true), best_icon_hash, random_order, icon_downloaded_at
			FROM hosts WHERE html_title IS NOT NULL AND icon_downloaded_at IS NOT NULL
			ORDER BY icon_downloaded_at, id LIMIT $1`
		args = []any{limit}
	} else {
		query = `SELECT id, hostname, protocol, html_title, COALESCE(iframe_allowed, true), best_icon_hash, random_order, icon_downloaded_at
			FROM hosts WHERE html_title IS NOT NULL AND icon_downloaded_at IS NOT NULL
			AND (icon_downloaded_at > $1 OR (icon_downloaded_at = $1 AND id > $2))
			ORDER BY icon_downloaded_at, id LIMIT $3`
		args = []any{lastDownloaded, lastID, limit}
	}
	rows, err := pool.Query(ctx, query, args...)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var hosts []HostRow
	for rows.Next() {
		var h HostRow
		if err := rows.Scan(&h.ID, &h.Hostname, &h.Protocol, &h.HtmlTitle, &h.IframeAllowed, &h.BestIconHash, &h.RandomOrder, &h.IconDownloadedAt); err != nil {
			return nil, err
		}
		hosts = append(hosts, h)
	}
	return hosts, rows.Err()
}

// fetchHostsWithoutIcons gets hosts without icons, ordered by id.
func fetchHostsWithoutIcons(ctx context.Context, pool *pgxpool.Pool, lastID int64, limit int) ([]HostRow, error) {
	rows, err := pool.Query(ctx, `
		SELECT id, hostname, protocol, html_title, COALESCE(iframe_allowed, true), '', random_order, NULL::timestamptz
		FROM hosts
		WHERE html_title IS NOT NULL AND icon_downloaded_at IS NULL AND id > $1
		ORDER BY id LIMIT $2
	`, lastID, limit)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var hosts []HostRow
	for rows.Next() {
		var h HostRow
		if err := rows.Scan(&h.ID, &h.Hostname, &h.Protocol, &h.HtmlTitle, &h.IframeAllowed, &h.BestIconHash, &h.RandomOrder, &h.IconDownloadedAt); err != nil {
			return nil, err
		}
		hosts = append(hosts, h)
	}
	return hosts, rows.Err()
}