package tools

import (
	"context"

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

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

type getComplianceOutput struct {
	Module           string                  `json:"module"`
	InterfaceAsserts []index.InterfaceAssert `json:"interfaceAsserts"`
	Tests            []index.ComplianceTest  `json:"tests"`
}

func registerGetCompliance(s *mcp.Server, idx *index.Index) {
	mcp.AddTool(s, &mcp.Tool{
		Name:        "get_compliance",
		Description: "Return a module's machine-checked conventions from compliance_test.go: every `var _ Iface = impl` interface assertion (the contracts the module promises to satisfy) and every Test* function (the structural rules the module enforces on itself). Use this before writing or reviewing code in a module to learn which conventions are actively guarded.",
	}, func(ctx context.Context, req *mcp.CallToolRequest, args getComplianceInput) (*mcp.CallToolResult, getComplianceOutput, error) {
		m := idx.FindModule(args.Module)
		if m == nil {
			return errorResult("module not found: " + args.Module), getComplianceOutput{}, nil
		}
		asserts := m.Compliance.InterfaceAsserts
		if asserts == nil {
			asserts = []index.InterfaceAssert{}
		}
		tests := m.Compliance.Tests
		if tests == nil {
			tests = []index.ComplianceTest{}
		}
		out := getComplianceOutput{
			Module:           m.Name,
			InterfaceAsserts: asserts,
			Tests:            tests,
		}
		return jsonText(out), out, nil
	})
}