Item price support

scripts/rsw/internal/wiki/exchange.go

@@ -0,0 +1,114 @@
+package wiki
+
+import (
+	"fmt"
+	"net/url"
+	"regexp"
+	"strconv"
+	"strings"
+)
+
+// RS3ExchangeItem holds metadata parsed from a Module:Exchange/<name> page.
+type RS3ExchangeItem struct {
+	ItemID   int
+	Name     string
+	Value    int
+	Limit    int
+	Members  bool
+	Category string
+	Examine  string
+}
+
+// revisionResponse matches the JSON from action=query&prop=revisions&rvslots=main.
+type revisionResponse struct {
+	Query struct {
+		Pages map[string]struct {
+			PageID    int    `json:"pageid"`
+			Title     string `json:"title"`
+			Revisions []struct {
+				Slots struct {
+					Main struct {
+						Content string `json:"*"`
+					} `json:"main"`
+				} `json:"slots"`
+			} `json:"revisions"`
+		} `json:"pages"`
+	} `json:"query"`
+}
+
+// GetExchangeModule fetches Module:Exchange/<name> and parses item metadata.
+// Returns nil, nil if the module page does not exist (item not tradeable).
+func (c *Client) GetExchangeModule(itemName string) (*RS3ExchangeItem, error) {
+	title := "Module:Exchange/" + itemName
+
+	params := url.Values{
+		"action":  {"query"},
+		"titles":  {title},
+		"prop":    {"revisions"},
+		"rvprop":  {"content"},
+		"rvslots": {"main"},
+	}
+
+	var resp revisionResponse
+	if err := c.get(params, &resp); err != nil {
+		return nil, fmt.Errorf("fetching exchange module: %w", err)
+	}
+
+	for id, page := range resp.Query.Pages {
+		// Page ID -1 means the page doesn't exist
+		if id == "-1" {
+			return nil, nil
+		}
+		if len(page.Revisions) == 0 {
+			return nil, nil
+		}
+
+		content := page.Revisions[0].Slots.Main.Content
+		return parseLuaModule(content), nil
+	}
+
+	return nil, nil
+}
+
+var (
+	reItemID   = regexp.MustCompile(`itemId\s*=\s*(\d+)`)
+	reItem     = regexp.MustCompile(`item\s*=\s*'((?:[^'\\]|\\.)*)'`)
+	reValue    = regexp.MustCompile(`value\s*=\s*(\d+)`)
+	reLimit    = regexp.MustCompile(`limit\s*=\s*(\d+)`)
+	reMembers  = regexp.MustCompile(`members\s*=\s*(true|false)`)
+	reCategory = regexp.MustCompile(`category\s*=\s*'((?:[^'\\]|\\.)*)'`)
+	reExamine  = regexp.MustCompile(`examine\s*=\s*'((?:[^'\\]|\\.)*)'`)
+)
+
+func parseLuaModule(content string) *RS3ExchangeItem {
+	item := &RS3ExchangeItem{}
+
+	if m := reItemID.FindStringSubmatch(content); m != nil {
+		item.ItemID, _ = strconv.Atoi(m[1])
+	}
+	if m := reItem.FindStringSubmatch(content); m != nil {
+		item.Name = unescapeLua(m[1])
+	}
+	if m := reValue.FindStringSubmatch(content); m != nil {
+		item.Value, _ = strconv.Atoi(m[1])
+	}
+	if m := reLimit.FindStringSubmatch(content); m != nil {
+		item.Limit, _ = strconv.Atoi(m[1])
+	}
+	if m := reMembers.FindStringSubmatch(content); m != nil {
+		item.Members = strings.ToLower(m[1]) == "true"
+	}
+	if m := reCategory.FindStringSubmatch(content); m != nil {
+		item.Category = unescapeLua(m[1])
+	}
+	if m := reExamine.FindStringSubmatch(content); m != nil {
+		item.Examine = unescapeLua(m[1])
+	}
+
+	return item
+}
+
+// unescapeLua handles Lua string escape sequences in single-quoted strings.
+func unescapeLua(s string) string {
+	return strings.NewReplacer(`\'`, `'`, `\\`, `\`).Replace(s)
+}