path: root/pkg/git/server.go

package git

import (
	"fmt"
	"os"
	"os/exec"
	"path/filepath"
	"strconv"
	"strings"

	"github.com/xlgmokha/mcp/pkg/mcp"
)

// Commit represents a git commit
type Commit struct {
	Hash    string
	Message string
	Author  string
	Date    string
}

// GitOperations provides git operations for a specific repository
type GitOperations struct {
	repoPath string
}

// NewGitOperations creates a new GitOperations helper
func NewGitOperations(repoPath string) *GitOperations {
	return &GitOperations{repoPath: repoPath}
}

// New creates a new Git MCP server
func New(repoPath string) *mcp.Server {
	git := NewGitOperations(repoPath)
	builder := mcp.NewServerBuilder("mcp-git", "1.0.0")

	// Add git_status tool
	builder.AddTool(mcp.NewTool("git_status", "Shows the working tree status", map[string]interface{}{
		"type": "object",
		"properties": map[string]interface{}{
			"repo_path": map[string]interface{}{
				"type":        "string",
				"description": "Path to the Git repository",
			},
		},
		"required": []string{"repo_path"},
	}, func(req mcp.CallToolRequest) (mcp.CallToolResult, error) {
		repoPath, ok := req.Arguments["repo_path"].(string)
		if !ok {
			repoPath = git.repoPath
		}

		output, err := git.runGitCommand(repoPath, "status")
		if err != nil {
			return mcp.NewToolError(fmt.Sprintf("git status failed: %v", err)), nil
		}

		return mcp.NewToolResult(mcp.NewTextContent(fmt.Sprintf("Repository status:\n%s", output))), nil
	}))

	// Add git_diff_unstaged tool
	builder.AddTool(mcp.NewTool("git_diff_unstaged", "Shows changes in the working directory that are not yet staged", map[string]interface{}{
		"type": "object",
		"properties": map[string]interface{}{
			"repo_path": map[string]interface{}{
				"type":        "string",
				"description": "Path to the Git repository",
			},
		},
		"required": []string{"repo_path"},
	}, func(req mcp.CallToolRequest) (mcp.CallToolResult, error) {
		repoPath, ok := req.Arguments["repo_path"].(string)
		if !ok {
			repoPath = git.repoPath
		}

		output, err := git.runGitCommand(repoPath, "diff")
		if err != nil {
			return mcp.NewToolError(fmt.Sprintf("git diff failed: %v", err)), nil
		}

		return mcp.NewToolResult(mcp.NewTextContent(fmt.Sprintf("Unstaged changes:\n%s", output))), nil
	}))

	// Add git_diff_staged tool
	builder.AddTool(mcp.NewTool("git_diff_staged", "Shows changes that are staged for commit", map[string]interface{}{
		"type": "object",
		"properties": map[string]interface{}{
			"repo_path": map[string]interface{}{
				"type":        "string",
				"description": "Path to the Git repository",
			},
		},
		"required": []string{"repo_path"},
	}, func(req mcp.CallToolRequest) (mcp.CallToolResult, error) {
		repoPath, ok := req.Arguments["repo_path"].(string)
		if !ok {
			repoPath = git.repoPath
		}

		output, err := git.runGitCommand(repoPath, "diff", "--cached")
		if err != nil {
			return mcp.NewToolError(fmt.Sprintf("git diff --cached failed: %v", err)), nil
		}

		return mcp.NewToolResult(mcp.NewTextContent(fmt.Sprintf("Staged changes:\n%s", output))), nil
	}))

	// Add git_diff tool
	builder.AddTool(mcp.NewTool("git_diff", "Shows differences between branches or commits", map[string]interface{}{
		"type": "object",
		"properties": map[string]interface{}{
			"repo_path": map[string]interface{}{
				"type":        "string",
				"description": "Path to the Git repository",
			},
			"target": map[string]interface{}{
				"type":        "string",
				"description": "Target branch or commit to diff against",
			},
		},
		"required": []string{"repo_path", "target"},
	}, func(req mcp.CallToolRequest) (mcp.CallToolResult, error) {
		repoPath, ok := req.Arguments["repo_path"].(string)
		if !ok {
			repoPath = git.repoPath
		}

		target, ok := req.Arguments["target"].(string)
		if !ok {
			return mcp.NewToolError("target is required"), nil
		}

		output, err := git.runGitCommand(repoPath, "diff", target)
		if err != nil {
			return mcp.NewToolError(fmt.Sprintf("git diff failed: %v", err)), nil
		}

		return mcp.NewToolResult(mcp.NewTextContent(fmt.Sprintf("Diff with %s:\n%s", target, output))), nil
	}))

	// Add git_commit tool
	builder.AddTool(mcp.NewTool("git_commit", "Records changes to the repository", map[string]interface{}{
		"type": "object",
		"properties": map[string]interface{}{
			"repo_path": map[string]interface{}{
				"type":        "string",
				"description": "Path to the Git repository",
			},
			"message": map[string]interface{}{
				"type":        "string",
				"description": "Commit message",
			},
		},
		"required": []string{"repo_path", "message"},
	}, func(req mcp.CallToolRequest) (mcp.CallToolResult, error) {
		repoPath, ok := req.Arguments["repo_path"].(string)
		if !ok {
			repoPath = git.repoPath
		}

		message, ok := req.Arguments["message"].(string)
		if !ok {
			return mcp.NewToolError("message is required"), nil
		}

		output, err := git.runGitCommand(repoPath, "commit", "-m", message)
		if err != nil {
			return mcp.NewToolError(fmt.Sprintf("git commit failed: %v", err)), nil
		}

		return mcp.NewToolResult(mcp.NewTextContent(fmt.Sprintf("Changes committed successfully:\n%s", output))), nil
	}))

	// Add git_add tool
	builder.AddTool(mcp.NewTool("git_add", "Adds file contents to the staging area", map[string]interface{}{
		"type": "object",
		"properties": map[string]interface{}{
			"repo_path": map[string]interface{}{
				"type":        "string",
				"description": "Path to the Git repository",
			},
			"files": map[string]interface{}{
				"type": "array",
				"items": map[string]interface{}{
					"type": "string",
				},
				"description": "List of files to add",
			},
		},
		"required": []string{"repo_path", "files"},
	}, func(req mcp.CallToolRequest) (mcp.CallToolResult, error) {
		repoPath, ok := req.Arguments["repo_path"].(string)
		if !ok {
			repoPath = git.repoPath
		}

		filesInterface, ok := req.Arguments["files"]
		if !ok {
			return mcp.NewToolError("files is required"), nil
		}

		files, err := convertToStringSlice(filesInterface)
		if err != nil {
			return mcp.NewToolError("files must be an array of strings"), nil
		}

		args := append([]string{"add"}, files...)
		_, err = git.runGitCommand(repoPath, args...)
		if err != nil {
			return mcp.NewToolError(fmt.Sprintf("git add failed: %v", err)), nil
		}

		return mcp.NewToolResult(mcp.NewTextContent("Files staged successfully")), nil
	}))

	// Add git_reset tool
	builder.AddTool(mcp.NewTool("git_reset", "Unstages all staged changes", map[string]interface{}{
		"type": "object",
		"properties": map[string]interface{}{
			"repo_path": map[string]interface{}{
				"type":        "string",
				"description": "Path to the Git repository",
			},
		},
		"required": []string{"repo_path"},
	}, func(req mcp.CallToolRequest) (mcp.CallToolResult, error) {
		repoPath, ok := req.Arguments["repo_path"].(string)
		if !ok {
			repoPath = git.repoPath
		}

		_, err := git.runGitCommand(repoPath, "reset")
		if err != nil {
			return mcp.NewToolError(fmt.Sprintf("git reset failed: %v", err)), nil
		}

		return mcp.NewToolResult(mcp.NewTextContent("All staged changes reset")), nil
	}))

	// Add git_log tool
	builder.AddTool(mcp.NewTool("git_log", "Shows the commit logs", map[string]interface{}{
		"type": "object",
		"properties": map[string]interface{}{
			"repo_path": map[string]interface{}{
				"type":        "string",
				"description": "Path to the Git repository",
			},
			"max_count": map[string]interface{}{
				"type":        "integer",
				"description": "Maximum number of commits to show",
				"default":     10,
			},
		},
		"required": []string{"repo_path"},
	}, func(req mcp.CallToolRequest) (mcp.CallToolResult, error) {
		repoPath, ok := req.Arguments["repo_path"].(string)
		if !ok {
			repoPath = git.repoPath
		}

		maxCount := 10
		if mc, exists := req.Arguments["max_count"]; exists {
			if count, ok := mc.(float64); ok {
				maxCount = int(count)
			}
		}

		output, err := git.runGitCommand(repoPath, "log", "--oneline", "-n", strconv.Itoa(maxCount))
		if err != nil {
			return mcp.NewToolError(fmt.Sprintf("git log failed: %v", err)), nil
		}

		return mcp.NewToolResult(mcp.NewTextContent(fmt.Sprintf("Commit history:\n%s", output))), nil
	}))

	// Add git_create_branch tool
	builder.AddTool(mcp.NewTool("git_create_branch", "Creates a new branch from an optional base branch", map[string]interface{}{
		"type": "object",
		"properties": map[string]interface{}{
			"repo_path": map[string]interface{}{
				"type":        "string",
				"description": "Path to the Git repository",
			},
			"branch_name": map[string]interface{}{
				"type":        "string",
				"description": "Name of the new branch",
			},
			"base_branch": map[string]interface{}{
				"type":        "string",
				"description": "Base branch to create from (optional)",
			},
		},
		"required": []string{"repo_path", "branch_name"},
	}, func(req mcp.CallToolRequest) (mcp.CallToolResult, error) {
		repoPath, ok := req.Arguments["repo_path"].(string)
		if !ok {
			repoPath = git.repoPath
		}

		branchName, ok := req.Arguments["branch_name"].(string)
		if !ok {
			return mcp.NewToolError("branch_name is required"), nil
		}

		baseBranch, _ := req.Arguments["base_branch"].(string)

		var args []string
		if baseBranch != "" {
			args = []string{"checkout", "-b", branchName, baseBranch}
		} else {
			args = []string{"checkout", "-b", branchName}
		}

		_, err := git.runGitCommand(repoPath, args...)
		if err != nil {
			return mcp.NewToolError(fmt.Sprintf("git create branch failed: %v", err)), nil
		}

		return mcp.NewToolResult(mcp.NewTextContent(fmt.Sprintf("Created branch '%s'", branchName))), nil
	}))

	// Add git_checkout tool
	builder.AddTool(mcp.NewTool("git_checkout", "Switches branches", map[string]interface{}{
		"type": "object",
		"properties": map[string]interface{}{
			"repo_path": map[string]interface{}{
				"type":        "string",
				"description": "Path to the Git repository",
			},
			"branch_name": map[string]interface{}{
				"type":        "string",
				"description": "Name of the branch to checkout",
			},
		},
		"required": []string{"repo_path", "branch_name"},
	}, func(req mcp.CallToolRequest) (mcp.CallToolResult, error) {
		repoPath, ok := req.Arguments["repo_path"].(string)
		if !ok {
			repoPath = git.repoPath
		}

		branchName, ok := req.Arguments["branch_name"].(string)
		if !ok {
			return mcp.NewToolError("branch_name is required"), nil
		}

		_, err := git.runGitCommand(repoPath, "checkout", branchName)
		if err != nil {
			return mcp.NewToolError(fmt.Sprintf("git checkout failed: %v", err)), nil
		}

		return mcp.NewToolResult(mcp.NewTextContent(fmt.Sprintf("Switched to branch '%s'", branchName))), nil
	}))

	// Add git_show tool
	builder.AddTool(mcp.NewTool("git_show", "Shows the contents of a commit", map[string]interface{}{
		"type": "object",
		"properties": map[string]interface{}{
			"repo_path": map[string]interface{}{
				"type":        "string",
				"description": "Path to the Git repository",
			},
			"revision": map[string]interface{}{
				"type":        "string",
				"description": "Commit hash or reference to show",
			},
		},
		"required": []string{"repo_path", "revision"},
	}, func(req mcp.CallToolRequest) (mcp.CallToolResult, error) {
		repoPath, ok := req.Arguments["repo_path"].(string)
		if !ok {
			repoPath = git.repoPath
		}

		revision, ok := req.Arguments["revision"].(string)
		if !ok {
			return mcp.NewToolError("revision is required"), nil
		}

		output, err := git.runGitCommand(repoPath, "show", revision)
		if err != nil {
			return mcp.NewToolError(fmt.Sprintf("git show failed: %v", err)), nil
		}

		return mcp.NewToolResult(mcp.NewTextContent(output)), nil
	}))

	// Add git_init tool
	builder.AddTool(mcp.NewTool("git_init", "Initialize a new Git repository", map[string]interface{}{
		"type": "object",
		"properties": map[string]interface{}{
			"repo_path": map[string]interface{}{
				"type":        "string",
				"description": "Path where to initialize the Git repository",
			},
		},
		"required": []string{"repo_path"},
	}, func(req mcp.CallToolRequest) (mcp.CallToolResult, error) {
		repoPath, ok := req.Arguments["repo_path"].(string)
		if !ok {
			repoPath = git.repoPath
		}

		if err := os.MkdirAll(repoPath, 0755); err != nil {
			return mcp.NewToolError(fmt.Sprintf("failed to create directory: %v", err)), nil
		}

		_, err := git.runGitCommand(repoPath, "init")
		if err != nil {
			return mcp.NewToolError(fmt.Sprintf("git init failed: %v", err)), nil
		}

		return mcp.NewToolResult(mcp.NewTextContent(fmt.Sprintf("Initialized empty Git repository in %s", repoPath))), nil
	}))

	// Add commit-message prompt
	builder.AddPrompt(mcp.NewPrompt("commit-message", "Prompt for crafting a well-structured git commit message", []mcp.PromptArgument{
		{
			Name:        "changes",
			Description: "Description of the changes being committed",
			Required:    true,
		},
		{
			Name:        "type",
			Description: "Type of change (feat, fix, docs, style, refactor, test, chore)",
			Required:    false,
		},
		{
			Name:        "breaking",
			Description: "Whether this is a breaking change (true/false)",
			Required:    false,
		},
	}, func(req mcp.GetPromptRequest) (mcp.GetPromptResult, error) {
		changes, hasChanges := req.Arguments["changes"].(string)
		commitType, hasType := req.Arguments["type"].(string)
		breaking, hasBreaking := req.Arguments["breaking"]

		if !hasChanges || changes == "" {
			return mcp.GetPromptResult{}, fmt.Errorf("changes argument is required")
		}

		if !hasType || commitType == "" {
			commitType = "feat"
		}

		isBreaking := false
		if hasBreaking {
			if breakingBool, ok := breaking.(bool); ok {
				isBreaking = breakingBool
			} else if breakingStr, ok := breaking.(string); ok {
				isBreaking = breakingStr == "true"
			}
		}

		var messages []mcp.PromptMessage

		userContent := fmt.Sprintf(`I need help writing a git commit message for the following changes:

%s

Please help me craft a well-structured commit message following conventional commit format.`, changes)

		if hasType {
			userContent += fmt.Sprintf("\n\nCommit type: %s", commitType)
		}
		if isBreaking {
			userContent += "\n\nThis is a BREAKING CHANGE."
		}

		messages = append(messages, mcp.PromptMessage{
			Role:    "user",
			Content: mcp.NewTextContent(userContent),
		})

		breakingPrefix := ""
		if isBreaking {
			breakingPrefix = "!"
		}

		assistantContent := fmt.Sprintf(`I'll help you create a conventional commit message. Here's the suggested format:

**Commit message:**
%s%s: %s

**Format explanation:**
- Type: %s (indicates the nature of the change)
- Description: Clear, concise summary in present tense
%s

**Additional guidelines:**
- Keep the subject line under 50 characters
- Use imperative mood ("add" not "added")
- Don't end subject line with a period
- Include body if needed to explain what and why`,
			commitType, breakingPrefix, changes,
			commitType,
			func() string {
				if isBreaking {
					return "- Breaking change: This change breaks backward compatibility"
				}
				return ""
			}())

		messages = append(messages, mcp.PromptMessage{
			Role:    "assistant",
			Content: mcp.NewTextContent(assistantContent),
		})

		description := fmt.Sprintf("Commit message guidance for %s changes", commitType)
		if isBreaking {
			description += " (BREAKING)"
		}

		return mcp.GetPromptResult{
			Description: description,
			Messages:    messages,
		}, nil
	}))

	// Add git:// pattern resource for dynamic file access
	builder.AddResource(mcp.NewResource(
		"git://",
		"Git Repository",
		"",
		func(req mcp.ReadResourceRequest) (mcp.ReadResourceResult, error) {
			return git.handleGitResource(req)
		},
	))

	// Add repository root if it's a git repository
	gitDir := filepath.Join(git.repoPath, ".git")
	if _, err := os.Stat(gitDir); err == nil {
		currentBranch, err := git.getCurrentBranch()
		if err != nil {
			currentBranch = "unknown"
		}

		gitURI := "git://" + git.repoPath
		repoName := filepath.Base(git.repoPath)
		if repoName == "." || repoName == "/" {
			repoName = git.repoPath
		}

		rootName := fmt.Sprintf("Git Repository: %s (branch: %s)", repoName, currentBranch)
		builder.AddRoot(mcp.NewRoot(gitURI, rootName))
	}

	return builder.Build()
}

// Helper methods for GitOperations

func (git *GitOperations) runGitCommand(repoPath string, args ...string) (string, error) {
	if _, err := os.Stat(repoPath); os.IsNotExist(err) {
		return "", fmt.Errorf("repository path does not exist: %s", repoPath)
	}

	if len(args) > 0 && args[0] != "init" {
		gitDir := filepath.Join(repoPath, ".git")
		if _, err := os.Stat(gitDir); os.IsNotExist(err) {
			return "", fmt.Errorf("not a git repository: %s", repoPath)
		}
	}

	cmd := exec.Command("git", args...)
	cmd.Dir = repoPath

	output, err := cmd.CombinedOutput()
	if err != nil {
		return "", fmt.Errorf("%v: %s", err, string(output))
	}

	return strings.TrimSpace(string(output)), nil
}

func (git *GitOperations) getCurrentBranch() (string, error) {
	output, err := git.runGitCommand(git.repoPath, "branch", "--show-current")
	if err != nil {
		return "", err
	}
	branch := strings.TrimSpace(output)
	if branch == "" {
		branch = "HEAD"
	}
	return branch, nil
}

func (git *GitOperations) getTrackedFiles() ([]string, error) {
	output, err := git.runGitCommand(git.repoPath, "ls-files")
	if err != nil {
		return nil, err
	}

	if output == "" {
		return []string{}, nil
	}

	files := strings.Split(output, "\n")
	var filteredFiles []string

	for _, file := range files {
		file = strings.TrimSpace(file)
		if file != "" && !strings.HasPrefix(file, ".") {
			filteredFiles = append(filteredFiles, file)
		}
	}

	return filteredFiles, nil
}

func (git *GitOperations) getBranches() ([]string, error) {
	output, err := git.runGitCommand(git.repoPath, "branch", "--format=%(refname:short)")
	if err != nil {
		return nil, err
	}

	if output == "" {
		return []string{}, nil
	}

	branches := strings.Split(output, "\n")
	var filteredBranches []string

	for _, branch := range branches {
		branch = strings.TrimSpace(branch)
		if branch != "" {
			filteredBranches = append(filteredBranches, branch)
		}
	}

	return filteredBranches, nil
}

func (git *GitOperations) getRecentCommits(count int) ([]Commit, error) {
	output, err := git.runGitCommand(git.repoPath, "log", "--format=%H|%s|%an|%ad", "--date=short", "-n", strconv.Itoa(count))
	if err != nil {
		return nil, err
	}

	if output == "" {
		return []Commit{}, nil
	}

	lines := strings.Split(output, "\n")
	var commits []Commit

	for _, line := range lines {
		line = strings.TrimSpace(line)
		if line == "" {
			continue
		}

		parts := strings.Split(line, "|")
		if len(parts) >= 4 {
			commits = append(commits, Commit{
				Hash:    parts[0],
				Message: parts[1],
				Author:  parts[2],
				Date:    parts[3],
			})
		}
	}

	return commits, nil
}

func (git *GitOperations) handleGitResource(req mcp.ReadResourceRequest) (mcp.ReadResourceResult, error) {
	if !strings.HasPrefix(req.URI, "git://") {
		return mcp.ReadResourceResult{}, fmt.Errorf("invalid git URI: %s", req.URI)
	}

	uriPath := req.URI[6:]
	parts := strings.Split(uriPath, "/")

	if len(parts) < 3 {
		return mcp.ReadResourceResult{}, fmt.Errorf("invalid git URI format: %s", req.URI)
	}

	repoPath := parts[0]
	resourceType := parts[1]
	resourcePath := strings.Join(parts[2:], "/")

	if repoPath != git.repoPath {
		return mcp.ReadResourceResult{}, fmt.Errorf("access denied: repository path mismatch")
	}

	switch resourceType {
	case "branch":
		return git.handleBranchResource(resourcePath)
	case "commit":
		return git.handleCommitResource(resourcePath)
	default:
		return git.handleFileResource(resourceType, resourcePath)
	}
}

func (git *GitOperations) handleFileResource(branch, filePath string) (mcp.ReadResourceResult, error) {
	gitPath := fmt.Sprintf("%s:%s", branch, filePath)
	output, err := git.runGitCommand(git.repoPath, "show", gitPath)
	if err != nil {
		return mcp.ReadResourceResult{}, fmt.Errorf("failed to read git file: %v", err)
	}

	return mcp.ReadResourceResult{
		Contents: []mcp.Content{
			mcp.NewTextContent(output),
		},
	}, nil
}

func (git *GitOperations) handleBranchResource(branchName string) (mcp.ReadResourceResult, error) {
	output, err := git.runGitCommand(git.repoPath, "log", "--oneline", "-n", "5", branchName)
	if err != nil {
		return mcp.ReadResourceResult{}, fmt.Errorf("failed to get branch info: %v", err)
	}

	content := fmt.Sprintf("Branch: %s\n\nRecent commits:\n%s", branchName, output)

	return mcp.ReadResourceResult{
		Contents: []mcp.Content{
			mcp.NewTextContent(content),
		},
	}, nil
}

func (git *GitOperations) handleCommitResource(commitHash string) (mcp.ReadResourceResult, error) {
	output, err := git.runGitCommand(git.repoPath, "show", "--stat", commitHash)
	if err != nil {
		return mcp.ReadResourceResult{}, fmt.Errorf("failed to get commit info: %v", err)
	}

	return mcp.ReadResourceResult{
		Contents: []mcp.Content{
			mcp.NewTextContent(output),
		},
	}, nil
}

// Helper function to convert interface{} to []string
func convertToStringSlice(input interface{}) ([]string, error) {
	switch v := input.(type) {
	case []interface{}:
		result := make([]string, len(v))
		for i, item := range v {
			str, ok := item.(string)
			if !ok {
				return nil, fmt.Errorf("item at index %d is not a string", i)
			}
			result[i] = str
		}
		return result, nil
	case []string:
		return v, nil
	default:
		return nil, fmt.Errorf("input is not a slice")
	}
}

// Helper function to determine MIME type for git files
func getGitMimeType(filePath string) string {
	ext := strings.ToLower(filepath.Ext(filePath))
	switch ext {
	case ".go":
		return "text/x-go"
	case ".js":
		return "text/javascript"
	case ".ts":
		return "text/typescript"
	case ".py":
		return "text/x-python"
	case ".md":
		return "text/markdown"
	case ".json":
		return "application/json"
	case ".yaml", ".yml":
		return "application/x-yaml"
	case ".xml":
		return "application/xml"
	case ".html", ".htm":
		return "text/html"
	case ".css":
		return "text/css"
	case ".txt":
		return "text/plain"
	default:
		return "text/plain"
	}
}