feat: add changelog command

internal/discord/commands.go

@@ -48,5 +48,25 @@ func getCommands() []*discordgo.ApplicationCommand {
 				},
 			},
 		},
+		{
+			Name:        "changelog",
+			Description: "View changes between two versions",
+			Options: []*discordgo.ApplicationCommandOption{
+				{
+					Type:         discordgo.ApplicationCommandOptionString,
+					Name:         "base",
+					Description:  "The base version (e.g. v2.6.0)",
+					Required:     true,
+					Autocomplete: true,
+				},
+				{
+					Type:         discordgo.ApplicationCommandOptionString,
+					Name:         "head",
+					Description:  "The head version (e.g. v2.6.4)",
+					Required:     true,
+					Autocomplete: true,
+				},
+			},
+		},
 	}
 }

internal/discord/handlers/changelog_handler.go

@@ -0,0 +1,170 @@
+package handlers
+
+import (
+	"fmt"
+	"log"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/bwmarrin/discordgo"
+	gogithub "github.com/google/go-github/v57/github"
+)
+
+var (
+	releaseCache      []*gogithub.RepositoryRelease
+	releaseCacheMutex sync.RWMutex
+	lastCacheUpdate   time.Time
+	cacheDuration     = 5 * time.Minute
+)
+
+func handleChangelog(s *discordgo.Session, i *discordgo.InteractionCreate) {
+	options := i.ApplicationCommandData().Options
+	optionMap := make(map[string]*discordgo.ApplicationCommandInteractionDataOption, len(options))
+	for _, opt := range options {
+		optionMap[opt.Name] = opt
+	}
+
+	var base, head string
+	if opt, ok := optionMap["base"]; ok {
+		base = opt.StringValue()
+	}
+	if opt, ok := optionMap["head"]; ok {
+		head = opt.StringValue()
+	}
+
+	if base == "" || head == "" {
+		s.InteractionRespond(i.Interaction, &discordgo.InteractionResponse{
+			Type: discordgo.InteractionResponseChannelMessageWithSource,
+			Data: &discordgo.InteractionResponseData{
+				Content: "Please provide both base and head versions.",
+				Flags:   discordgo.MessageFlagsEphemeral,
+			},
+		})
+		return
+	}
+
+	// Defer response as API call might take time
+	s.InteractionRespond(i.Interaction, &discordgo.InteractionResponse{
+		Type: discordgo.InteractionResponseDeferredChannelMessageWithSource,
+	})
+
+	comparison, err := GithubClient.CompareCommits(GithubOwner, GithubRepo, base, head)
+	if err != nil {
+		log.Printf("Error comparing commits: %v", err)
+		s.InteractionResponseEdit(i.Interaction, &discordgo.WebhookEdit{
+			Content: &[]string{fmt.Sprintf("Failed to compare versions: %s...%s", base, head)}[0],
+		})
+		return
+	}
+
+	// Format the output
+	message := formatChangelogMessage(base, head, comparison)
+
+	s.InteractionResponseEdit(i.Interaction, &discordgo.WebhookEdit{
+		Content: &message,
+	})
+}
+
+func formatChangelogMessage(base, head string, comparison *gogithub.CommitsComparison) string {
+	var sb strings.Builder
+	sb.WriteString(fmt.Sprintf("## Changes from %s to %s\n", base, head))
+	sb.WriteString(fmt.Sprintf("Total commits: %d\n\n", comparison.GetTotalCommits()))
+
+	// List commits (limit to last 10 to avoid hitting message length limits)
+	commits := comparison.Commits
+	if len(commits) > 10 {
+		sb.WriteString(fmt.Sprintf("*Showing last 10 of %d commits*\n\n", len(commits)))
+		commits = commits[len(commits)-10:]
+	}
+
+	for _, commit := range commits {
+		message := commit.GetCommit().GetMessage()
+		// Take only the first line of the commit message
+		if idx := strings.Index(message, "\n"); idx != -1 {
+			message = message[:idx]
+		}
+
+		author := commit.GetAuthor().GetLogin()
+		if author == "" {
+			author = commit.GetCommit().GetAuthor().GetName()
+		}
+
+		sb.WriteString(fmt.Sprintf("- [`%s`](<%s>) %s - *%s*\n",
+			commit.GetSHA()[:7],
+			commit.GetHTMLURL(),
+			message,
+			author,
+		))
+	}
+
+	sb.WriteString(fmt.Sprintf("\n[View Full Comparison](<%s>)", comparison.GetHTMLURL()))
+	return sb.String()
+}
+
+func handleChangelogAutocomplete(s *discordgo.Session, i *discordgo.InteractionCreate) {
+	// Update cache if needed
+	if err := updateReleaseCache(); err != nil {
+		log.Printf("Error updating release cache: %v", err)
+	}
+
+	releaseCacheMutex.RLock()
+	defer releaseCacheMutex.RUnlock()
+
+	data := i.ApplicationCommandData()
+	var currentInput string
+	for _, opt := range data.Options {
+		if opt.Focused {
+			currentInput = strings.ToLower(opt.StringValue())
+			break
+		}
+	}
+
+	choices := make([]*discordgo.ApplicationCommandOptionChoice, 0, 25)
+	for _, release := range releaseCache {
+		tagName := release.GetTagName()
+		if currentInput == "" || strings.Contains(strings.ToLower(tagName), currentInput) {
+			choices = append(choices, &discordgo.ApplicationCommandOptionChoice{
+				Name:  tagName,
+				Value: tagName,
+			})
+		}
+		if len(choices) >= 25 {
+			break
+		}
+	}
+
+	s.InteractionRespond(i.Interaction, &discordgo.InteractionResponse{
+		Type: discordgo.InteractionApplicationCommandAutocompleteResult,
+		Data: &discordgo.InteractionResponseData{
+			Choices: choices,
+		},
+	})
+}
+
+func updateReleaseCache() error {
+	releaseCacheMutex.RLock()
+	if time.Since(lastCacheUpdate) < cacheDuration && len(releaseCache) > 0 {
+		releaseCacheMutex.RUnlock()
+		return nil
+	}
+	releaseCacheMutex.RUnlock()
+
+	releaseCacheMutex.Lock()
+	defer releaseCacheMutex.Unlock()
+
+	// Double check after acquiring write lock
+	if time.Since(lastCacheUpdate) < cacheDuration && len(releaseCache) > 0 {
+		return nil
+	}
+
+	// Fetch releases
+	releases, err := GithubClient.GetReleases(GithubOwner, GithubRepo, 100)
+	if err != nil {
+		return err
+	}
+
+	releaseCache = releases
+	lastCacheUpdate = time.Now()
+	return nil
+}

internal/discord/handlers/changelog_handler_test.go

@@ -0,0 +1,121 @@
+package handlers
+
+import (
+	"strings"
+	"testing"
+
+	gogithub "github.com/google/go-github/v57/github"
+)
+
+func TestFormatChangelogMessage(t *testing.T) {
+	strPtr := func(s string) *string { return &s }
+	intPtr := func(i int) *int { return &i }
+
+	tests := []struct {
+		name       string
+		base       string
+		head       string
+		comparison *gogithub.CommitsComparison
+		want       []string // Substrings that should be present
+		dontWant   []string // Substrings that should NOT be present
+	}{
+		{
+			name: "basic comparison",
+			base: "v1.0.0",
+			head: "v1.1.0",
+			comparison: &gogithub.CommitsComparison{
+				TotalCommits: intPtr(2),
+				HTMLURL:      strPtr("https://github.com/org/repo/compare/v1.0.0...v1.1.0"),
+				Commits: []*gogithub.RepositoryCommit{
+					{
+						SHA:     strPtr("abcdef123456"),
+						HTMLURL: strPtr("https://github.com/org/repo/commit/abcdef1"),
+						Commit: &gogithub.Commit{
+							Message: strPtr("feat: cool feature"),
+							Author: &gogithub.CommitAuthor{
+								Name: strPtr("John Doe"),
+							},
+						},
+						Author: &gogithub.User{
+							Login: strPtr("johndoe"),
+						},
+					},
+					{
+						SHA:     strPtr("123456abcdef"),
+						HTMLURL: strPtr("https://github.com/org/repo/commit/123456a"),
+						Commit: &gogithub.Commit{
+							Message: strPtr("fix: nasty bug\n\nSome details"),
+							Author: &gogithub.CommitAuthor{
+								Name: strPtr("Jane Smith"),
+							},
+						},
+						Author: &gogithub.User{
+							Login: strPtr("janesmith"),
+						},
+					},
+				},
+			},
+			want: []string{
+				"## Changes from v1.0.0 to v1.1.0",
+				"Total commits: 2",
+				"[`abcdef1`](<https://github.com/org/repo/commit/abcdef1>)",
+				"feat: cool feature",
+				"johndoe",
+				"[`123456a`](<https://github.com/org/repo/commit/123456a>)",
+				"fix: nasty bug",
+				"janesmith",
+				"[View Full Comparison](<https://github.com/org/repo/compare/v1.0.0...v1.1.0>)",
+			},
+			dontWant: []string{
+				"Some details",
+				"Showing last 10",
+			},
+		},
+		{
+			name: "many commits truncated",
+			base: "v1.0.0",
+			head: "v1.1.0",
+			comparison: &gogithub.CommitsComparison{
+				TotalCommits: intPtr(15),
+				HTMLURL:      strPtr("https://github.com/compare"),
+				Commits: func() []*gogithub.RepositoryCommit {
+					commits := make([]*gogithub.RepositoryCommit, 15)
+					for i := 0; i < 15; i++ {
+						commits[i] = &gogithub.RepositoryCommit{
+							SHA:     strPtr("longhashvalue"),
+							HTMLURL: strPtr("url"),
+							Commit: &gogithub.Commit{
+								Message: strPtr("msg"),
+								Author:  &gogithub.CommitAuthor{Name: strPtr("author")},
+							},
+							Author: &gogithub.User{Login: strPtr("user")},
+						}
+					}
+					return commits
+				}(),
+			},
+			want: []string{
+				"Total commits: 15",
+				"*Showing last 10 of 15 commits*",
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got := formatChangelogMessage(tt.base, tt.head, tt.comparison)
+
+			for _, w := range tt.want {
+				if !strings.Contains(got, w) {
+					t.Errorf("formatChangelogMessage() missing %q\nGot:\n%s", w, got)
+				}
+			}
+
+			for _, dw := range tt.dontWant {
+				if strings.Contains(got, dw) {
+					t.Errorf("formatChangelogMessage() unexpectedly contains %q", dw)
+				}
+			}
+		})
+	}
+}

internal/discord/handlers/interaction.go

@@ -34,10 +34,11 @@ type ModalState struct {
 var modalStates = make(map[string]*ModalState)
 
 var commandHandlers = map[string]func(s *discordgo.Session, i *discordgo.InteractionCreate){
-	"tapsign": handleTapsign,
-	"feature": handleFeature,
-	"faq":     handleFaq,
-	"bug":     handleBug,
+	"tapsign":   handleTapsign,
+	"feature":   handleFeature,
+	"faq":       handleFaq,
+	"bug":       handleBug,
+	"changelog": handleChangelog,
 }
 
 // HandleInteraction routes interactions to appropriate handlers
@@ -60,7 +61,8 @@ func handleTapsign(s *discordgo.Session, i *discordgo.InteractionCreate) {
 	helpText := "**How to get help or make a suggestion:**\n" +
 		"`/bug`: To report a bug with the app.\n" +
 		"`/feature`: To request a new feature. \n" +
-		"`/faq`: Frequently Asked Questions.\n"
+		"`/faq`: Frequently Asked Questions.\n" +
+		"`/changelog`: View changes between two versions.\n"
 
 	s.InteractionRespond(i.Interaction, &discordgo.InteractionResponse{
 		Type: discordgo.InteractionResponseChannelMessageWithSource,
@@ -77,5 +79,7 @@ func handleAutocomplete(s *discordgo.Session, i *discordgo.InteractionCreate) {
 	switch data.Name {
 	case "faq":
 		handleFaqAutocomplete(s, i)
+	case "changelog":
+		handleChangelogAutocomplete(s, i)
 	}
 }

internal/github/client.go

@@ -40,6 +40,25 @@ func NewClient(token string) *Client {
 	}
 }
 
+func (c *Client) GetReleases(owner, repo string, limit int) ([]*github.RepositoryRelease, error) {
+	opts := &github.ListOptions{
+		PerPage: limit,
+	}
+	releases, _, err := c.client.Repositories.ListReleases(c.ctx, owner, repo, opts)
+	if err != nil {
+		return nil, fmt.Errorf("failed to list releases: %w", err)
+	}
+	return releases, nil
+}
+
+func (c *Client) CompareCommits(owner, repo, base, head string) (*github.CommitsComparison, error) {
+	comparison, _, err := c.client.Repositories.CompareCommits(c.ctx, owner, repo, base, head, nil)
+	if err != nil {
+		return nil, fmt.Errorf("failed to compare commits: %w", err)
+	}
+	return comparison, nil
+}
+
 func (c *Client) CreateIssue(owner, repo, title, body string, labels []string) (*IssueResponse, error) {
 	log.Printf("[GitHub API] Creating issue in %s/%s", owner, repo)
 	log.Printf("[GitHub API] Title: %s", title)