package repo

import (
	"context"
	"fmt"

	"gitea.com/gitea/gitea-mcp/pkg/gitea"
	"gitea.com/gitea/gitea-mcp/pkg/log"
	"gitea.com/gitea/gitea-mcp/pkg/params"
	"gitea.com/gitea/gitea-mcp/pkg/to"

	"github.com/mark3labs/mcp-go/mcp"
	"github.com/mark3labs/mcp-go/server"
)

const (
	GetCompareToolName = "get_compare"
)

var (
	GetCompareTool = mcp.NewTool(
		GetCompareToolName,
		mcp.WithDescription("Compare two branches, tags, or commits. Returns commits and diff stats between the base and head."),
		mcp.WithString("owner", mcp.Required(), mcp.Description("repository owner")),
		mcp.WithString("repo", mcp.Required(), mcp.Description("repository name")),
		mcp.WithString("basehead", mcp.Required(), mcp.Description("comparison in format 'base...head' (e.g. 'main...feature-branch')")),
	)
)

func init() {
	Tool.RegisterRead(server.ServerTool{
		Tool:    GetCompareTool,
		Handler: getCompareFn,
	})
}

func getCompareFn(ctx context.Context, req mcp.CallToolRequest) (*mcp.CallToolResult, error) {
	log.Debugf("Called getCompareFn")
	args := req.GetArguments()
	owner, err := params.GetString(args, "owner")
	if err != nil {
		return to.ErrorResult(err)
	}
	repo, err := params.GetString(args, "repo")
	if err != nil {
		return to.ErrorResult(err)
	}
	basehead, err := params.GetString(args, "basehead")
	if err != nil {
		return to.ErrorResult(err)
	}

	var result map[string]any
	_, err = gitea.DoJSON(ctx, "GET", fmt.Sprintf("repos/%s/%s/compare/%s", owner, repo, basehead), nil, nil, &result)
	if err != nil {
		return to.ErrorResult(fmt.Errorf("compare %v in %v/%v err: %v", basehead, owner, repo, err))
	}
	return to.TextResult(result)
}