| 1 | // Package billing queries a provider's wallet balance for the status line. The |
| 2 | // only documented shape today is DeepSeek's GET /user/balance, so Fetch speaks |
| 3 | // that schema. Balance is strictly optional: a provider with no balance_url is |
| 4 | // never queried — callers pass "" and get (nil, nil) back, and surfaces simply |
| 5 | // omit the readout. Kept tiny and dependency-free (net/http + encoding/json) so |
| 6 | // every frontend can share one fetch. |
| 7 | package billing |
| 8 | |
| 9 | import ( |
| 10 | "context" |
| 11 | "encoding/json" |
| 12 | "fmt" |
| 13 | "io" |
| 14 | "net/http" |
| 15 | "sort" |
| 16 | "strings" |
| 17 | "time" |
| 18 | ) |
| 19 | |
| 20 | // Balance is a wallet balance normalized for display. |
| 21 | type Balance struct { |
| 22 | Available bool // the provider reports the account can still serve API calls |
| 23 | Infos []Info // one entry per currency the provider returns |
| 24 | } |
| 25 | |
| 26 | // Currencies returns the distinct ISO currency codes reported by the wallet, |
| 27 | // in stable order. It never converts or combines balances. |
| 28 | func (b *Balance) Currencies() []string { |
| 29 | if b == nil { |
| 30 | return nil |
| 31 | } |
| 32 | seen := map[string]struct{}{} |
| 33 | for _, info := range b.Infos { |
| 34 | cur := strings.ToUpper(strings.TrimSpace(info.Currency)) |
| 35 | if normalized := normalizeCurrency(cur); normalized != "" { |
| 36 | cur = normalized |
| 37 | } |
| 38 | if cur != "" { |
| 39 | seen[cur] = struct{}{} |
| 40 | } |
| 41 | } |
| 42 | result := make([]string, 0, len(seen)) |
| 43 | for cur := range seen { |
| 44 | result = append(result, cur) |
| 45 | } |
| 46 | sort.Strings(result) |
| 47 | return result |
| 48 | } |
| 49 | |
| 50 | // PrimaryCurrency returns the sole usable wallet currency, if there is one. |
| 51 | func (b *Balance) PrimaryCurrency() string { |
| 52 | currencies := b.Currencies() |
| 53 | if len(currencies) != 1 { |
| 54 | return "" |
| 55 | } |
| 56 | if currencies[0] != "CNY" && currencies[0] != "USD" { |
| 57 | return "" |
| 58 | } |
| 59 | return currencies[0] |
| 60 | } |
| 61 | |
| 62 | // MultiCurrency reports whether more than one wallet currency is present. |
| 63 | func (b *Balance) MultiCurrency() bool { return len(b.Currencies()) > 1 } |
| 64 | |
| 65 | // Info is one currency's balance (DeepSeek returns one per currency). |
| 66 | type Info struct { |
| 67 | Currency string // "CNY" | "USD" |
| 68 | TotalBalance string // total available (granted + topped-up) |
| 69 | GrantedBalance string // unexpired promotional credit |
| 70 | ToppedUpBalance string // paid-in credit |
| 71 | } |
| 72 | |
| 73 | // deepseekResp mirrors the GET /user/balance response shape. |
| 74 | type deepseekResp struct { |
| 75 | IsAvailable bool `json:"is_available"` |
| 76 | BalanceInfos []struct { |
| 77 | Currency string `json:"currency"` |
| 78 | TotalBalance string `json:"total_balance"` |
| 79 | GrantedBalance string `json:"granted_balance"` |
| 80 | ToppedUpBalance string `json:"topped_up_balance"` |
| 81 | } `json:"balance_infos"` |
| 82 | } |
| 83 | |
| 84 | // httpClient bounds the balance query so a slow endpoint can't hang the status |
| 85 | // line; the per-call ctx still cancels it on shutdown. |
| 86 | var httpClient = &http.Client{Timeout: 12 * time.Second} |
| 87 | |
| 88 | // Fetch queries url (a DeepSeek-style balance endpoint) with a Bearer apiKey and |
| 89 | // returns the normalized balance. An empty url yields (nil, nil) — "not |
| 90 | // configured", not an error — so callers can treat both the same and just omit |
| 91 | // the readout. |
| 92 | func Fetch(ctx context.Context, url, apiKey string) (*Balance, error) { |
| 93 | return FetchWithClient(ctx, httpClient, url, apiKey) |
| 94 | } |
| 95 | |
| 96 | // FetchWithClient queries the balance endpoint using the caller-provided client. |
| 97 | // A nil client falls back to the package default. |
| 98 | func FetchWithClient(ctx context.Context, client *http.Client, url, apiKey string) (*Balance, error) { |
| 99 | if strings.TrimSpace(url) == "" { |
| 100 | return nil, nil |
| 101 | } |
| 102 | if client == nil { |
| 103 | client = httpClient |
| 104 | } |
| 105 | req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil) |
| 106 | if err != nil { |
| 107 | return nil, err |
| 108 | } |
| 109 | req.Header.Set("Accept", "application/json") |
| 110 | if apiKey != "" { |
| 111 | req.Header.Set("Authorization", "Bearer "+apiKey) |
| 112 | } |
| 113 | resp, err := client.Do(req) |
| 114 | if err != nil { |
| 115 | return nil, err |
| 116 | } |
| 117 | defer resp.Body.Close() |
| 118 | body, _ := io.ReadAll(io.LimitReader(resp.Body, 1<<16)) |
| 119 | if resp.StatusCode != http.StatusOK { |
| 120 | return nil, fmt.Errorf("balance: status %d: %s", resp.StatusCode, strings.TrimSpace(string(body))) |
| 121 | } |
| 122 | var dr deepseekResp |
| 123 | if err := json.Unmarshal(body, &dr); err != nil { |
| 124 | return nil, fmt.Errorf("balance: decode: %w", err) |
| 125 | } |
| 126 | b := &Balance{Available: dr.IsAvailable} |
| 127 | for _, bi := range dr.BalanceInfos { |
| 128 | b.Infos = append(b.Infos, Info{ |
| 129 | Currency: bi.Currency, |
| 130 | TotalBalance: bi.TotalBalance, |
| 131 | GrantedBalance: bi.GrantedBalance, |
| 132 | ToppedUpBalance: bi.ToppedUpBalance, |
| 133 | }) |
| 134 | } |
| 135 | return b, nil |
| 136 | } |
| 137 | |
| 138 | // symbol maps an ISO currency code to a compact symbol; an unknown code passes |
| 139 | // through with a trailing space ("XYZ 12.00"). |
| 140 | func symbol(currency string) string { |
| 141 | switch strings.ToUpper(currency) { |
| 142 | case "CNY", "RMB": |
| 143 | return "¥" |
| 144 | case "USD": |
| 145 | return "$" |
| 146 | default: |
| 147 | if currency == "" { |
| 148 | return "" |
| 149 | } |
| 150 | return currency + " " |
| 151 | } |
| 152 | } |
| 153 | |
| 154 | // Display renders the primary balance compactly, e.g. "¥110.00". It preserves |
| 155 | // the legacy CNY-first behavior for callers that have no display-currency |
| 156 | // preference. |
| 157 | func (b *Balance) Display() string { |
| 158 | return b.DisplayForCurrency("") |
| 159 | } |
| 160 | |
| 161 | // DisplayForCurrency renders the balance matching the requested pricing |
| 162 | // currency. When the provider does not return that currency, it falls back to |
| 163 | // Display's legacy CNY-first selection and prefixes the provider's real ISO |
| 164 | // currency (for example "CNY ¥70.16"); it never performs an implicit |
| 165 | // exchange-rate conversion. |
| 166 | func (b *Balance) DisplayForCurrency(currency string) string { |
| 167 | if b == nil || len(b.Infos) == 0 { |
| 168 | return "" |
| 169 | } |
| 170 | pick := b.Infos[0] |
| 171 | preferred := normalizeCurrency(currency) |
| 172 | if preferred != "" { |
| 173 | for _, i := range b.Infos { |
| 174 | if normalizeCurrency(i.Currency) == preferred { |
| 175 | return symbol(i.Currency) + strings.TrimSpace(i.TotalBalance) |
| 176 | } |
| 177 | } |
| 178 | } |
| 179 | for _, i := range b.Infos { |
| 180 | if normalizeCurrency(i.Currency) == "CNY" { |
| 181 | pick = i |
| 182 | break |
| 183 | } |
| 184 | } |
| 185 | display := symbol(pick.Currency) + strings.TrimSpace(pick.TotalBalance) |
| 186 | actual := strings.ToUpper(strings.TrimSpace(pick.Currency)) |
| 187 | if normalized := normalizeCurrency(actual); normalized != "" { |
| 188 | actual = normalized |
| 189 | } |
| 190 | if preferred != "" && actual != "" && actual != preferred { |
| 191 | return actual + " " + display |
| 192 | } |
| 193 | return display |
| 194 | } |
| 195 | |
| 196 | func normalizeCurrency(currency string) string { |
| 197 | switch strings.ToUpper(strings.TrimSpace(currency)) { |
| 198 | case "CNY", "RMB", "CNH", "¥", "￥": |
| 199 | return "CNY" |
| 200 | case "USD", "$", "US$": |
| 201 | return "USD" |
| 202 | default: |
| 203 | return "" |
| 204 | } |
| 205 | } |
| 206 |