labmcp/internal/gitexplorer/handlers.go

package gitexplorer

import (
	"context"
	"fmt"

	"code.t-juice.club/torjus/labmcp/internal/mcp"
)

// RegisterHandlers registers all git-explorer tool handlers on the MCP server.
func RegisterHandlers(server *mcp.Server, client *GitClient) {
	server.RegisterTool(resolveRefTool(), makeResolveRefHandler(client))
	server.RegisterTool(getLogTool(), makeGetLogHandler(client))
	server.RegisterTool(getCommitInfoTool(), makeGetCommitInfoHandler(client))
	server.RegisterTool(getDiffFilesTool(), makeGetDiffFilesHandler(client))
	server.RegisterTool(getFileAtCommitTool(), makeGetFileAtCommitHandler(client))
	server.RegisterTool(isAncestorTool(), makeIsAncestorHandler(client))
	server.RegisterTool(commitsBetweenTool(), makeCommitsBetweenHandler(client))
	server.RegisterTool(listBranchesTool(), makeListBranchesHandler(client))
	server.RegisterTool(searchCommitsTool(), makeSearchCommitsHandler(client))
}

// Tool definitions

func resolveRefTool() mcp.Tool {
	return mcp.Tool{
		Name:        "resolve_ref",
		Description: "Resolve a git ref (branch, tag, or commit hash) to its full commit hash",
		InputSchema: mcp.InputSchema{
			Type: "object",
			Properties: map[string]mcp.Property{
				"ref": {
					Type:        "string",
					Description: "Git ref to resolve (e.g., 'main', 'v1.0.0', 'HEAD', commit hash)",
				},
			},
			Required: []string{"ref"},
		},
	}
}

func getLogTool() mcp.Tool {
	return mcp.Tool{
		Name:        "get_log",
		Description: "Get commit log starting from a ref, with optional filters",
		InputSchema: mcp.InputSchema{
			Type: "object",
			Properties: map[string]mcp.Property{
				"ref": {
					Type:        "string",
					Description: "Starting ref for the log (default: HEAD)",
				},
				"limit": {
					Type:        "integer",
					Description: fmt.Sprintf("Maximum number of commits to return (default: 20, max: %d)", Limits.MaxLogEntries),
					Default:     20,
				},
				"author": {
					Type:        "string",
					Description: "Filter by author name or email (substring match)",
				},
				"since": {
					Type:        "string",
					Description: "Stop log at this ref (exclusive)",
				},
				"path": {
					Type:        "string",
					Description: "Filter commits that affect this path",
				},
			},
		},
	}
}

func getCommitInfoTool() mcp.Tool {
	return mcp.Tool{
		Name:        "get_commit_info",
		Description: "Get full details for a specific commit including message, author, and optionally file statistics",
		InputSchema: mcp.InputSchema{
			Type: "object",
			Properties: map[string]mcp.Property{
				"ref": {
					Type:        "string",
					Description: "Commit ref (hash, branch, tag, or HEAD)",
				},
				"include_stats": {
					Type:        "boolean",
					Description: "Include file change statistics (default: true)",
					Default:     true,
				},
			},
			Required: []string{"ref"},
		},
	}
}

func getDiffFilesTool() mcp.Tool {
	return mcp.Tool{
		Name:        "get_diff_files",
		Description: "Get list of files changed between two commits with change type and line counts",
		InputSchema: mcp.InputSchema{
			Type: "object",
			Properties: map[string]mcp.Property{
				"from_ref": {
					Type:        "string",
					Description: "Starting commit ref (the older commit)",
				},
				"to_ref": {
					Type:        "string",
					Description: "Ending commit ref (the newer commit)",
				},
			},
			Required: []string{"from_ref", "to_ref"},
		},
	}
}

func getFileAtCommitTool() mcp.Tool {
	return mcp.Tool{
		Name:        "get_file_at_commit",
		Description: fmt.Sprintf("Get the contents of a file at a specific commit (max %dKB)", Limits.MaxFileContent/1024),
		InputSchema: mcp.InputSchema{
			Type: "object",
			Properties: map[string]mcp.Property{
				"ref": {
					Type:        "string",
					Description: "Commit ref (hash, branch, tag, or HEAD)",
				},
				"path": {
					Type:        "string",
					Description: "Path to the file relative to repository root",
				},
			},
			Required: []string{"ref", "path"},
		},
	}
}

func isAncestorTool() mcp.Tool {
	return mcp.Tool{
		Name:        "is_ancestor",
		Description: "Check if one commit is an ancestor of another",
		InputSchema: mcp.InputSchema{
			Type: "object",
			Properties: map[string]mcp.Property{
				"ancestor": {
					Type:        "string",
					Description: "Potential ancestor commit ref",
				},
				"descendant": {
					Type:        "string",
					Description: "Potential descendant commit ref",
				},
			},
			Required: []string{"ancestor", "descendant"},
		},
	}
}

func commitsBetweenTool() mcp.Tool {
	return mcp.Tool{
		Name:        "commits_between",
		Description: "Get all commits between two refs (from is exclusive, to is inclusive)",
		InputSchema: mcp.InputSchema{
			Type: "object",
			Properties: map[string]mcp.Property{
				"from_ref": {
					Type:        "string",
					Description: "Starting commit ref (exclusive - commits after this)",
				},
				"to_ref": {
					Type:        "string",
					Description: "Ending commit ref (inclusive - up to and including this)",
				},
				"limit": {
					Type:        "integer",
					Description: fmt.Sprintf("Maximum number of commits (default: %d)", Limits.MaxLogEntries),
					Default:     Limits.MaxLogEntries,
				},
			},
			Required: []string{"from_ref", "to_ref"},
		},
	}
}

func listBranchesTool() mcp.Tool {
	return mcp.Tool{
		Name:        "list_branches",
		Description: "List all branches in the repository",
		InputSchema: mcp.InputSchema{
			Type: "object",
			Properties: map[string]mcp.Property{
				"include_remote": {
					Type:        "boolean",
					Description: "Include remote-tracking branches (default: false)",
					Default:     false,
				},
			},
		},
	}
}

func searchCommitsTool() mcp.Tool {
	return mcp.Tool{
		Name:        "search_commits",
		Description: "Search commit messages for a pattern (case-insensitive)",
		InputSchema: mcp.InputSchema{
			Type: "object",
			Properties: map[string]mcp.Property{
				"query": {
					Type:        "string",
					Description: "Search pattern to match in commit messages",
				},
				"ref": {
					Type:        "string",
					Description: "Starting ref for the search (default: HEAD)",
				},
				"limit": {
					Type:        "integer",
					Description: fmt.Sprintf("Maximum number of results (default: 20, max: %d)", Limits.MaxSearchResult),
					Default:     20,
				},
			},
			Required: []string{"query"},
		},
	}
}

// Handler constructors

func makeResolveRefHandler(client *GitClient) mcp.ToolHandler {
	return func(ctx context.Context, args map[string]interface{}) (mcp.CallToolResult, error) {
		ref, _ := args["ref"].(string)
		if ref == "" {
			return mcp.ErrorContent(fmt.Errorf("ref is required")), nil
		}

		result, err := client.ResolveRef(ref)
		if err != nil {
			return mcp.ErrorContent(err), nil
		}

		return mcp.CallToolResult{
			Content: []mcp.Content{mcp.TextContent(FormatResolveResult(result))},
		}, nil
	}
}

func makeGetLogHandler(client *GitClient) mcp.ToolHandler {
	return func(ctx context.Context, args map[string]interface{}) (mcp.CallToolResult, error) {
		ref := "HEAD"
		if r, ok := args["ref"].(string); ok && r != "" {
			ref = r
		}

		limit := 20
		if l, ok := args["limit"].(float64); ok && l > 0 {
			limit = int(l)
		}

		author, _ := args["author"].(string)
		since, _ := args["since"].(string)
		path, _ := args["path"].(string)

		entries, err := client.GetLog(ref, limit, author, since, path)
		if err != nil {
			return mcp.ErrorContent(err), nil
		}

		return mcp.CallToolResult{
			Content: []mcp.Content{mcp.TextContent(FormatLogEntries(entries))},
		}, nil
	}
}

func makeGetCommitInfoHandler(client *GitClient) mcp.ToolHandler {
	return func(ctx context.Context, args map[string]interface{}) (mcp.CallToolResult, error) {
		ref, _ := args["ref"].(string)
		if ref == "" {
			return mcp.ErrorContent(fmt.Errorf("ref is required")), nil
		}

		includeStats := true
		if s, ok := args["include_stats"].(bool); ok {
			includeStats = s
		}

		info, err := client.GetCommitInfo(ref, includeStats)
		if err != nil {
			return mcp.ErrorContent(err), nil
		}

		return mcp.CallToolResult{
			Content: []mcp.Content{mcp.TextContent(FormatCommitInfo(info))},
		}, nil
	}
}

func makeGetDiffFilesHandler(client *GitClient) mcp.ToolHandler {
	return func(ctx context.Context, args map[string]interface{}) (mcp.CallToolResult, error) {
		fromRef, _ := args["from_ref"].(string)
		if fromRef == "" {
			return mcp.ErrorContent(fmt.Errorf("from_ref is required")), nil
		}

		toRef, _ := args["to_ref"].(string)
		if toRef == "" {
			return mcp.ErrorContent(fmt.Errorf("to_ref is required")), nil
		}

		result, err := client.GetDiffFiles(fromRef, toRef)
		if err != nil {
			return mcp.ErrorContent(err), nil
		}

		return mcp.CallToolResult{
			Content: []mcp.Content{mcp.TextContent(FormatDiffResult(result))},
		}, nil
	}
}

func makeGetFileAtCommitHandler(client *GitClient) mcp.ToolHandler {
	return func(ctx context.Context, args map[string]interface{}) (mcp.CallToolResult, error) {
		ref, _ := args["ref"].(string)
		if ref == "" {
			return mcp.ErrorContent(fmt.Errorf("ref is required")), nil
		}

		path, _ := args["path"].(string)
		if path == "" {
			return mcp.ErrorContent(fmt.Errorf("path is required")), nil
		}

		content, err := client.GetFileAtCommit(ref, path)
		if err != nil {
			return mcp.ErrorContent(err), nil
		}

		return mcp.CallToolResult{
			Content: []mcp.Content{mcp.TextContent(FormatFileContent(content))},
		}, nil
	}
}

func makeIsAncestorHandler(client *GitClient) mcp.ToolHandler {
	return func(ctx context.Context, args map[string]interface{}) (mcp.CallToolResult, error) {
		ancestor, _ := args["ancestor"].(string)
		if ancestor == "" {
			return mcp.ErrorContent(fmt.Errorf("ancestor is required")), nil
		}

		descendant, _ := args["descendant"].(string)
		if descendant == "" {
			return mcp.ErrorContent(fmt.Errorf("descendant is required")), nil
		}

		result, err := client.IsAncestor(ancestor, descendant)
		if err != nil {
			return mcp.ErrorContent(err), nil
		}

		return mcp.CallToolResult{
			Content: []mcp.Content{mcp.TextContent(FormatAncestryResult(result))},
		}, nil
	}
}

func makeCommitsBetweenHandler(client *GitClient) mcp.ToolHandler {
	return func(ctx context.Context, args map[string]interface{}) (mcp.CallToolResult, error) {
		fromRef, _ := args["from_ref"].(string)
		if fromRef == "" {
			return mcp.ErrorContent(fmt.Errorf("from_ref is required")), nil
		}

		toRef, _ := args["to_ref"].(string)
		if toRef == "" {
			return mcp.ErrorContent(fmt.Errorf("to_ref is required")), nil
		}

		limit := Limits.MaxLogEntries
		if l, ok := args["limit"].(float64); ok && l > 0 {
			limit = int(l)
		}

		result, err := client.CommitsBetween(fromRef, toRef, limit)
		if err != nil {
			return mcp.ErrorContent(err), nil
		}

		return mcp.CallToolResult{
			Content: []mcp.Content{mcp.TextContent(FormatCommitRange(result))},
		}, nil
	}
}

func makeListBranchesHandler(client *GitClient) mcp.ToolHandler {
	return func(ctx context.Context, args map[string]interface{}) (mcp.CallToolResult, error) {
		includeRemote := false
		if r, ok := args["include_remote"].(bool); ok {
			includeRemote = r
		}

		result, err := client.ListBranches(includeRemote)
		if err != nil {
			return mcp.ErrorContent(err), nil
		}

		return mcp.CallToolResult{
			Content: []mcp.Content{mcp.TextContent(FormatBranchList(result))},
		}, nil
	}
}

func makeSearchCommitsHandler(client *GitClient) mcp.ToolHandler {
	return func(ctx context.Context, args map[string]interface{}) (mcp.CallToolResult, error) {
		query, _ := args["query"].(string)
		if query == "" {
			return mcp.ErrorContent(fmt.Errorf("query is required")), nil
		}

		ref := "HEAD"
		if r, ok := args["ref"].(string); ok && r != "" {
			ref = r
		}

		limit := 20
		if l, ok := args["limit"].(float64); ok && l > 0 {
			limit = int(l)
		}

		result, err := client.SearchCommits(ref, query, limit)
		if err != nil {
			return mcp.ErrorContent(err), nil
		}

		return mcp.CallToolResult{
			Content: []mcp.Content{mcp.TextContent(FormatSearchResult(result))},
		}, nil
	}
}