package mcp

import "encoding/json"

// Tiny JSON-Schema builders for tool input schemas. They keep tool definitions
// readable without a schema dependency.

// Props is a set of named property schemas for Object.
type Props map[string]json.RawMessage

// Object builds an object JSON Schema from named property schemas and the list
// of required keys. required may be nil.
func Object(p Props, required []string) json.RawMessage {
	schema := map[string]any{"type": "object"}
	if len(p) > 0 {
		schema["properties"] = p
	} else {
		schema["properties"] = map[string]any{}
	}
	if len(required) > 0 {
		schema["required"] = required
	}
	b, _ := json.Marshal(schema)
	return b
}

// Scalar builds a single-typed schema with a description (e.g. Scalar("integer", …)).
func Scalar(typ, desc string) json.RawMessage {
	b, _ := json.Marshal(map[string]string{"type": typ, "description": desc})
	return b
}

func String(desc string) json.RawMessage  { return Scalar("string", desc) }
func Integer(desc string) json.RawMessage { return Scalar("integer", desc) }
func Number(desc string) json.RawMessage  { return Scalar("number", desc) }
func Bool(desc string) json.RawMessage    { return Scalar("boolean", desc) }
func ObjectValue(desc string) json.RawMessage {
	return Scalar("object", desc)
}

// StringArray builds an array-of-strings schema.
func StringArray(desc string) json.RawMessage {
	b, _ := json.Marshal(map[string]any{
		"type": "array", "description": desc, "items": map[string]string{"type": "string"},
	})
	return b
}

// ObjectArray builds an array-of-objects schema.
func ObjectArray(desc string) json.RawMessage {
	b, _ := json.Marshal(map[string]any{
		"type": "array", "description": desc, "items": map[string]string{"type": "object"},
	})
	return b
}

// IntegerArray builds an array-of-integers schema.
func IntegerArray(desc string) json.RawMessage {
	b, _ := json.Marshal(map[string]any{
		"type": "array", "description": desc, "items": map[string]string{"type": "integer"},
	})
	return b
}