pkg/eax: Implement EAX API client

2 files changed, 325 insertions, 0 deletions

diff --git a/pkg/eax/eax.go b/pkg/eax/eax.go
new file mode 100644
index 0000000..34f5702
--- /dev/null
+++ b/pkg/eax/eax.go
@@ -0,0 +1,145 @@
+// Package eax queries the EA App API.
+package eax
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"mime"
+	"net/http"
+	"net/url"
+	"strconv"
+)
+
+type Client struct {
+	// The [net/http.Client] to use for requests. If not provided,
+	// [net/http.DefaultClient] is used.
+	Client *http.Client
+
+	// The UpdateMgr for requests which require version information.
+	UpdateMgr *UpdateMgr
+}
+
+var ErrVersionRequired = errors.New("client version is required for this endpoint")
+
+// PlayerID contains basic identifiers and names for a player.
+type PlayerID struct {
+	PD          uint64 // origin ID
+	PSD         uint64 // ?
+	DisplayName string // in-game name
+	Nickname    string // social name?
+}
+
+// PlayerByPd gets basic information about an Origin ID. If the player does not
+// exist, nil will be returned.
+func (c *Client) PlayerIDByPD(ctx context.Context, pd uint64) (*PlayerID, error) {
+	var obj struct {
+		PlayerByPD *struct {
+			PD          string `json:"pd"`
+			PSD         string `json:"psd"`
+			DisplayName string `json:"displayName"`
+			Nickname    string `json:"nickname"`
+		} `json:"playerByPd"`
+	}
+	if err := c.gql1(ctx, true, `query { playerByPd (pd: `+strconv.FormatUint(pd, 10)+`) { pd psd displayName nickname } }`, &obj); err != nil {
+		return nil, err
+	}
+	if obj.PlayerByPD == nil {
+		return nil, nil
+	}
+	res := &PlayerID{
+		DisplayName: obj.PlayerByPD.DisplayName,
+		Nickname:    obj.PlayerByPD.Nickname,
+	}
+	if s := obj.PlayerByPD.PD; s != "" {
+		if v, err := strconv.ParseUint(s, 10, 64); err == nil {
+			res.PD = v
+		} else {
+			return res, fmt.Errorf("parse pd %q: %w", s, err)
+		}
+	}
+	if s := obj.PlayerByPD.PSD; s != "" {
+		if v, err := strconv.ParseUint(s, 10, 64); err == nil {
+			res.PD = v
+		} else {
+			return res, fmt.Errorf("parse psd %q: %w", s, err)
+		}
+	}
+	return res, nil
+}
+
+// gql1 performs a basic GraphQL query.
+func (c *Client) gql1(ctx context.Context, ver bool, query string, out any) error {
+	req, err := c.req(ctx, ver, http.MethodGet, "https://service-aggregation-layer.juno.ea.com/graphql?query="+url.QueryEscape(query), nil)
+	if err != nil {
+		return err
+	}
+
+	resp, err := c.do(req)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+
+	if mt, _, _ := mime.ParseMediaType(resp.Header.Get("Content-Type")); mt != "application/json" {
+		if resp.StatusCode != http.StatusOK {
+			return fmt.Errorf("response status %d (%s) with content-type %q", resp.StatusCode, resp.Status, mt)
+		}
+		return fmt.Errorf("unexpected content-type %q", mt)
+	}
+
+	buf, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return err
+	}
+
+	var obj struct {
+		Data   json.RawMessage `json:"data"`
+		Errors []struct {
+			Message string `json:"message"`
+		} `json:"errors"`
+	}
+	if err := json.Unmarshal(buf, &obj); err != nil {
+		if resp.StatusCode != http.StatusOK {
+			return fmt.Errorf("response status %d (%s) with invalid json", resp.StatusCode, resp.Status)
+		}
+		return fmt.Errorf("invalid json resp: %w", err)
+	}
+	if len(obj.Errors) != 0 {
+		return fmt.Errorf("got %d errors, including %q", len(obj.Errors), obj.Errors[0].Message)
+	}
+	if err := json.Unmarshal([]byte(obj.Data), out); err != nil {
+		return fmt.Errorf("invalid json data: %w", err)
+	}
+	return nil
+}
+
+func (c *Client) do(r *http.Request) (*http.Response, error) {
+	if c.Client == nil {
+		return http.DefaultClient.Do(r)
+	}
+	return c.Client.Do(r)
+}
+
+func (c *Client) req(ctx context.Context, ver bool, method, url string, body io.Reader) (*http.Request, error) {
+	req, err := http.NewRequestWithContext(ctx, method, url, body)
+	if err == nil {
+		if ver {
+			if c.UpdateMgr == nil {
+				return nil, ErrVersionRequired
+			}
+			ver, _, err := c.UpdateMgr.Update(false)
+			if err != nil {
+				return nil, fmt.Errorf("%w: failed to update version: %v", ErrVersionRequired, err)
+			}
+			if ver == "" {
+				return nil, ErrVersionRequired
+			}
+			req.Header.Set("User-Agent", "EADesktop/"+ver)
+		}
+		req.Header.Set("x-client-id", "EAX-JUNO-CLIENT")
+	}
+	return req, err
+}
diff --git a/pkg/eax/updatemgr.go b/pkg/eax/updatemgr.go
new file mode 100644
index 0000000..d1a6a59
--- /dev/null
+++ b/pkg/eax/updatemgr.go
@@ -0,0 +1,180 @@
+package eax
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"net/http"
+	"strconv"
+	"sync"
+	"time"
+)
+
+// UpdateMgr manages EAX client version information.
+type UpdateMgr struct {
+	// HTTP client to use. If not provided, [net/http.DefaultClient] will be
+	// used.
+	Client *http.Client
+
+	// Timeout is the timeout for refreshing tokens. If zero, a reasonable
+	// default is used. If negative, there is no timeout.
+	Timeout time.Duration
+
+	// Interval to update at. If zero, will not auto-update.
+	AutoUpdateInterval time.Duration
+
+	// Auto-update staged roll-out bucket.
+	AutoUpdateBucket int
+
+	// Auto-update backoff, if provided, checks if another auto-update is
+	// allowed after a failure. If it returns false, ErrAutoUpdateBackoff will be
+	// returned from the function triggering the auto-update.
+	AutoUpdateBackoff func(err error, time time.Time, count int) bool
+
+	// AutoUpdateHook is called for every auto-update attempt with the new (or
+	// current if error) version, and any error which occurred.
+	AutoUpdateHook func(v string, err error)
+
+	verInit     sync.Once
+	verPf       bool       // ensures only one auto-update runs at a time
+	verCv       *sync.Cond // allows other goroutines to wait for that update to complete
+	verErr      error      // last auto-update error
+	verErrTime  time.Time  // last auto-update error time
+	verErrCount int        // consecutive auto-update errors
+	ver         string     // current version
+	verTime     time.Time  // last update check time
+}
+
+var ErrAutoUpdateBackoff = errors.New("not updating eax client version due to backoff")
+
+func (u *UpdateMgr) init() {
+	u.verInit.Do(func() {
+		u.verCv = sync.NewCond(new(sync.Mutex))
+	})
+}
+
+// SetVersion sets the current version.
+func (u *UpdateMgr) SetVersion(v string) {
+	u.init()
+	u.verCv.L.Lock()
+	for u.verPf {
+		u.verCv.Wait()
+	}
+	u.ver = v
+	u.verErr = nil
+	u.verTime = time.Now()
+	u.verCv.L.Unlock()
+}
+
+// Update gets the latest version, following u.AutoUpdateInterval if provided,
+// unless the version is not set or force is true. If another update is in
+// progress, it waits for the result of it. True is returned (on success or
+// failure) if this call performed a update. This function may block for up to
+// Timeout.
+func (u *UpdateMgr) Update(force bool) (string, bool, error) {
+	u.init()
+	if u.verCv.L.Lock(); u.verPf {
+		for u.verPf {
+			u.verCv.Wait()
+		}
+		defer u.verCv.L.Unlock()
+		return u.ver, false, u.verErr
+	} else {
+		if force || u.ver == "" || (u.AutoUpdateInterval != 0 && time.Since(u.verTime) > u.AutoUpdateInterval) {
+			u.verPf = true
+			u.verCv.L.Unlock()
+			defer func() {
+				u.verCv.L.Lock()
+				u.verCv.Broadcast()
+				u.verPf = false
+				u.verCv.L.Unlock()
+			}()
+		} else {
+			defer u.verCv.L.Unlock()
+			return u.ver, false, u.verErr
+		}
+	}
+	if u.verErr != nil && u.AutoUpdateBackoff != nil {
+		if !u.AutoUpdateBackoff(u.verErr, u.verErrTime, u.verErrCount) {
+			return u.ver, true, fmt.Errorf("%w (%d attempts, last error: %v)", ErrAutoUpdateBackoff, u.verErrCount, u.verErr)
+		}
+	}
+	u.verErr = func() error {
+		var ctx context.Context
+		var cancel context.CancelFunc
+		if u.Timeout > 0 {
+			ctx, cancel = context.WithTimeout(context.Background(), u.Timeout)
+		} else if u.Timeout == 0 {
+			ctx, cancel = context.WithTimeout(context.Background(), time.Second*15)
+		} else {
+			ctx, cancel = context.WithCancel(context.Background())
+		}
+		defer cancel()
+
+		req, err := http.NewRequestWithContext(ctx, http.MethodGet, "https://autopatch.juno.ea.com/autopatch/upgrade/buckets/"+strconv.Itoa(u.AutoUpdateBucket), nil)
+		if err != nil {
+			return err
+		}
+		if u.ver != "" {
+			req.Header.Set("User-Agent", "EADesktop/"+u.ver)
+		} else {
+			req.Header.Set("User-Agent", "")
+		}
+
+		cl := u.Client
+		if cl == nil {
+			cl = http.DefaultClient
+		}
+
+		resp, err := cl.Do(req)
+		if err != nil {
+			return err
+		}
+		defer resp.Body.Close()
+
+		var obj struct {
+			Minimum struct {
+				Version        string `json:"version"`
+				ActivationDate string `json:"activationDate"`
+			} `json:"minimum"`
+			Recommended struct {
+				Version string `json:"version"`
+			} `json:"recommended"`
+		}
+		if resp.StatusCode != http.StatusOK {
+			return fmt.Errorf("response status %d (%s)", resp.StatusCode, resp.Status)
+		}
+		if err := json.NewDecoder(resp.Body).Decode(&obj); err != nil {
+			return fmt.Errorf("parse autopatch response: %w", err)
+		}
+
+		var version string
+		if v := obj.Minimum.Version; v != "" {
+			version = v
+		}
+		if v := obj.Recommended.Version; v != "" {
+			version = v
+		}
+		if version == "" {
+			return fmt.Errorf("parse autopatch response: missing minimum or recommended version")
+		}
+		u.ver = version
+		u.verTime = time.Now()
+		return nil
+	}()
+	if u.verErrCount != 0 {
+		u.verErr = fmt.Errorf("%w (attempt %d)", u.verErr, u.verErrCount)
+	}
+	if u.verErr != nil {
+		u.verErrCount++
+		u.verErrTime = time.Now()
+	} else {
+		u.verErrCount = 0
+		u.verErrTime = time.Time{}
+	}
+	if u.AutoUpdateHook != nil {
+		go u.AutoUpdateHook(u.ver, u.verErr)
+	}
+	return u.ver, true, u.verErr
+}