package tools

import (
	"context"

	"code.nochebuena.dev/einherjar/mcp/internal/index"
	"github.com/modelcontextprotocol/go-sdk/mcp"
)

type getChangelogInput struct {
	Module string `json:"module" jsonschema:"the module name, e.g. core"`
}

type getChangelogOutput struct {
	Module    string `json:"module"`
	Changelog string `json:"changelog"`
}

func registerGetChangelog(s *mcp.Server, idx *index.Index) {
	mcp.AddTool(s, &mcp.Tool{
		Name:        "get_changelog",
		Description: "Return the CHANGELOG.md markdown for one Einherjar module. Use to learn what changed in recent releases and to advise on upgrade-relevant differences.",
	}, func(ctx context.Context, req *mcp.CallToolRequest, args getChangelogInput) (*mcp.CallToolResult, getChangelogOutput, error) {
		m := idx.FindModule(args.Module)
		if m == nil {
			return errorResult("module not found: " + args.Module), getChangelogOutput{}, nil
		}
		out := getChangelogOutput{Module: m.Name, Changelog: m.Changelog}
		return jsonText(out), out, nil
	})
}