b8a0fd5f35
Full rewrite of the gaming deals Matrix bot in Go for better performance and a single static binary. Includes all original functionality (CheapShark, ITAD, Epic free games, multi-currency pricing, dedup, preflight checks, presence heartbeat) plus a new watchlist feature where users can DM the bot to watch for specific game deals with 180-day auto-expiry. New: systemd service file, DB migration script for Python-to-Go transition. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
97 lines
1.9 KiB
Go
97 lines
1.9 KiB
Go
package currency
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import (
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"encoding/json"
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"fmt"
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"log/slog"
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"net/http"
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"strings"
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"sync"
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"time"
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)
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const (
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apiURL = "https://api.frankfurter.dev/v1/latest?base=USD&symbols=CAD,EUR,GBP"
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cacheTTL = 12 * time.Hour
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)
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var symbols = map[string]string{
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"USD": "$",
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"CAD": "C$",
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"EUR": "€",
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"GBP": "£",
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}
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var currencies = []string{"CAD", "EUR", "GBP"}
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type Converter struct {
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mu sync.Mutex
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rates map[string]float64
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lastFetched time.Time
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}
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func NewConverter() *Converter {
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return &Converter{}
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}
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func (c *Converter) fetchRates() error {
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resp, err := http.Get(apiURL)
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if err != nil {
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return err
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}
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defer resp.Body.Close()
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if resp.StatusCode != http.StatusOK {
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return fmt.Errorf("frankfurter API returned status %d", resp.StatusCode)
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}
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var result struct {
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Rates map[string]float64 `json:"rates"`
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}
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if err := json.NewDecoder(resp.Body).Decode(&result); err != nil {
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return err
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}
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c.rates = result.Rates
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c.lastFetched = time.Now()
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return nil
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}
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// EnsureRates fetches exchange rates if the cache is stale or empty.
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func (c *Converter) EnsureRates() {
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c.mu.Lock()
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defer c.mu.Unlock()
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if time.Since(c.lastFetched) < cacheTTL && c.rates != nil {
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return
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}
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if err := c.fetchRates(); err != nil {
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slog.Warn("failed to fetch exchange rates, using USD only", "error", err)
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}
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}
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// FormatPrice converts a USD amount to multi-currency display string.
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func (c *Converter) FormatPrice(usd float64) string {
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c.mu.Lock()
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defer c.mu.Unlock()
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parts := []string{fmt.Sprintf("$%.2f", usd)}
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for _, cur := range currencies {
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if rate, ok := c.rates[cur]; ok {
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sym := symbols[cur]
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parts = append(parts, fmt.Sprintf("%s%.2f", sym, usd*rate))
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}
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}
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return strings.Join(parts, " · ")
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}
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// HasRates returns true if exchange rates are available.
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func (c *Converter) HasRates() bool {
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c.mu.Lock()
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defer c.mu.Unlock()
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return c.rates != nil && len(c.rates) > 0
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}
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