Item price support

scripts/rsw/internal/prices/rs3client.go

@@ -0,0 +1,125 @@
+package prices
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"time"
+)
+
+const rs3BaseURL = "https://secure.runescape.com/m=itemdb_rs"
+
+// RS3Client wraps HTTP requests to the Jagex RS3 Grand Exchange API.
+type RS3Client struct {
+	httpClient *http.Client
+}
+
+// NewRS3Client creates an RS3 price API client.
+func NewRS3Client() *RS3Client {
+	return &RS3Client{
+		httpClient: &http.Client{
+			Timeout: 15 * time.Second,
+		},
+	}
+}
+
+// RS3ItemDetail holds current price and trend data for an RS3 item.
+type RS3ItemDetail struct {
+	ID           int
+	Name         string
+	Description  string
+	Members      string
+	CurrentPrice string // pre-formatted, e.g. "91.6b"
+	CurrentTrend string
+	TodayPrice   int
+	TodayTrend   string
+	Day30Change  string
+	Day30Trend   string
+	Day90Change  string
+	Day90Trend   string
+	Day180Change string
+	Day180Trend  string
+}
+
+// rs3DetailResponse matches the JSON shape from the Jagex catalogue API.
+type rs3DetailResponse struct {
+	Item struct {
+		ID          int    `json:"id"`
+		Name        string `json:"name"`
+		Description string `json:"description"`
+		Type        string `json:"type"`
+		Members     string `json:"members"`
+		Current     struct {
+			Trend string      `json:"trend"`
+			Price any `json:"price"` // string or int
+		} `json:"current"`
+		Today struct {
+			Trend string `json:"trend"`
+			Price any    `json:"price"` // int or string
+		} `json:"today"`
+		Day30 struct {
+			Trend  string `json:"trend"`
+			Change string `json:"change"`
+		} `json:"day30"`
+		Day90 struct {
+			Trend  string `json:"trend"`
+			Change string `json:"change"`
+		} `json:"day90"`
+		Day180 struct {
+			Trend  string `json:"trend"`
+			Change string `json:"change"`
+		} `json:"day180"`
+	} `json:"item"`
+}
+
+// GetDetail fetches current price and trend data for an RS3 item by ID.
+func (c *RS3Client) GetDetail(itemID int) (*RS3ItemDetail, error) {
+	url := fmt.Sprintf("%s/api/catalogue/detail.json?item=%d", rs3BaseURL, itemID)
+
+	req, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		return nil, fmt.Errorf("creating request: %w", err)
+	}
+	req.Header.Set("User-Agent", userAgent)
+
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("executing request: %w", err)
+	}
+	defer resp.Body.Close() //nolint:errcheck
+
+	if resp.StatusCode != http.StatusOK {
+		body, _ := io.ReadAll(resp.Body)
+		return nil, fmt.Errorf("RS3 API returned status %d: %s", resp.StatusCode, string(body))
+	}
+
+	var raw rs3DetailResponse
+	if err := json.NewDecoder(resp.Body).Decode(&raw); err != nil {
+		return nil, fmt.Errorf("decoding response: %w", err)
+	}
+
+	detail := &RS3ItemDetail{
+		ID:           raw.Item.ID,
+		Name:         raw.Item.Name,
+		Description:  raw.Item.Description,
+		Members:      raw.Item.Members,
+		CurrentPrice: fmt.Sprintf("%v", raw.Item.Current.Price),
+		CurrentTrend: raw.Item.Current.Trend,
+		TodayTrend:   raw.Item.Today.Trend,
+		Day30Change:  raw.Item.Day30.Change,
+		Day30Trend:   raw.Item.Day30.Trend,
+		Day90Change:  raw.Item.Day90.Change,
+		Day90Trend:   raw.Item.Day90.Trend,
+		Day180Change: raw.Item.Day180.Change,
+		Day180Trend:  raw.Item.Day180.Trend,
+	}
+
+	// today.price can be int or string
+	switch v := raw.Item.Today.Price.(type) {
+	case float64:
+		detail.TodayPrice = int(v)
+	}
+
+	return detail, nil
+}