add: modrinth client and check command

1 files changed, 128 insertions, 0 deletions

diff --git a/internal/modrinth/modrinth.go b/internal/modrinth/modrinth.go
new file mode 100644
index 0000000..8060f3b
--- /dev/null
+++ b/internal/modrinth/modrinth.go
@@ -0,0 +1,128 @@
+package modrinth
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"time"
+)
+
+const (
+	apiBase   = "https://api.modrinth.com/v2"
+	userAgent = "benson/2.0 (github.com/hachem-wtf/benson)"
+)
+
+type File struct {
+	URL      string `json:"url"`
+	Filename string `json:"filename"`
+	Primary  bool   `json:"primary"`
+}
+
+type Version struct {
+	ID            string    `json:"id"`
+	VersionNumber string    `json:"version_number"`
+	DatePublished time.Time `json:"date_published"`
+	GameVersions  []string  `json:"game_versions"`
+	Loaders       []string  `json:"loaders"`
+	Files         []File    `json:"files"`
+}
+
+type Client struct {
+	http *http.Client
+}
+
+func NewClient() *Client {
+	return &Client{http: &http.Client{Timeout: 30 * time.Second}}
+}
+
+func (c *Client) GetVersions(slug string) ([]Version, error) {
+	url := fmt.Sprintf("%s/project/%s/version", apiBase, slug)
+
+	req, err := http.NewRequest(http.MethodGet, url, nil)
+	if err != nil {
+		return nil, err
+	}
+	req.Header.Set("User-Agent", userAgent)
+
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("modrinth: %s returned %s", slug, resp.Status)
+	}
+
+	var versions []Version
+	if err := json.NewDecoder(resp.Body).Decode(&versions); err != nil {
+		return nil, err
+	}
+	return versions, nil
+}
+
+func LatestVersion(versions []Version) *Version {
+	if len(versions) == 0 {
+		return nil
+	}
+
+	best := 0
+	for i := 1; i < len(versions); i++ {
+		if versions[i].DatePublished.After(versions[best].DatePublished) {
+			best = i
+		}
+	}
+	return &versions[best]
+}
+
+func CompatibleVersion(versions []Version, mcVersion, loader string) *Version {
+	var compatible []Version
+	for _, v := range versions {
+		if !contains(v.GameVersions, mcVersion) {
+			continue
+		}
+		if loader != "" && !contains(v.Loaders, loader) {
+			continue
+		}
+		compatible = append(compatible, v)
+	}
+	return LatestVersion(compatible)
+}
+
+func (c *Client) Download(url, dest string) error {
+	req, err := http.NewRequest(http.MethodGet, url, nil)
+	if err != nil {
+		return err
+	}
+	req.Header.Set("User-Agent", userAgent)
+
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return err
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return fmt.Errorf("download: %s returned %s", url, resp.Status)
+	}
+
+	f, err := os.Create(dest)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	_, err = io.Copy(f, resp.Body)
+	return err
+}
+
+func contains(list []string, s string) bool {
+	for _, item := range list {
+		if item == s {
+			return true
+		}
+	}
+	return false
+}