package config

import (
	"fmt"
	"strings"
)

func ValidateConfig(c Config) error {
	if err := ValidateAdminConfig(c.Admin); err != nil {
		return err
	}
	if err := ValidateRuntimeConfig(c.Runtime); err != nil {
		return err
	}
	if err := ValidateResponsesConfig(c.Responses); err != nil {
		return err
	}
	if err := ValidateEmbeddingsConfig(c.Embeddings); err != nil {
		return err
	}
	if err := ValidateAutoDeleteConfig(c.AutoDelete); err != nil {
		return err
	}
	return nil
}

func ValidateAdminConfig(admin AdminConfig) error {
	return ValidateIntRange("admin.jwt_expire_hours", admin.JWTExpireHours, 1, 720, false)
}

func ValidateRuntimeConfig(runtime RuntimeConfig) error {
	if err := ValidateIntRange("runtime.account_max_inflight", runtime.AccountMaxInflight, 1, 256, false); err != nil {
		return err
	}
	if err := ValidateIntRange("runtime.account_max_queue", runtime.AccountMaxQueue, 1, 200000, false); err != nil {
		return err
	}
	if err := ValidateIntRange("runtime.global_max_inflight", runtime.GlobalMaxInflight, 1, 200000, false); err != nil {
		return err
	}
	if err := ValidateIntRange("runtime.token_refresh_interval_hours", runtime.TokenRefreshIntervalHours, 1, 720, false); err != nil {
		return err
	}
	if runtime.AccountMaxInflight > 0 && runtime.GlobalMaxInflight > 0 && runtime.GlobalMaxInflight < runtime.AccountMaxInflight {
		return fmt.Errorf("runtime.global_max_inflight must be >= runtime.account_max_inflight")
	}
	return nil
}

func ValidateResponsesConfig(responses ResponsesConfig) error {
	return ValidateIntRange("responses.store_ttl_seconds", responses.StoreTTLSeconds, 30, 86400, false)
}

func ValidateEmbeddingsConfig(embeddings EmbeddingsConfig) error {
	return ValidateTrimmedString("embeddings.provider", embeddings.Provider, false)
}

func ValidateAutoDeleteConfig(autoDelete AutoDeleteConfig) error {
	return ValidateAutoDeleteMode(autoDelete.Mode)
}

func ValidateIntRange(name string, value, min, max int, required bool) error {
	if value == 0 && !required {
		return nil
	}
	if value < min || value > max {
		return fmt.Errorf("%s must be between %d and %d", name, min, max)
	}
	return nil
}

func ValidateTrimmedString(name, value string, required bool) error {
	trimmed := strings.TrimSpace(value)
	if trimmed == "" {
		if !required && value == "" {
			return nil
		}
		return fmt.Errorf("%s cannot be empty", name)
	}
	return nil
}

func ValidateAutoDeleteMode(mode string) error {
	mode = strings.ToLower(strings.TrimSpace(mode))
	switch mode {
	case "", "none", "single", "all":
		return nil
	default:
		return fmt.Errorf("auto_delete.mode must be one of none, single, all")
	}
}