package domain

import (
	"errors"
	"math"
	"time"
)

const maxExecutionTimeoutSeconds int64 = math.MaxInt64 / int64(time.Second)

// ValidateExecutionTargetSettings validates source-neutral execution-setting
// invariants on a resolved target.
func ValidateExecutionTargetSettings(target ExecutionTarget) error {
	if !isFinite(target.Temperature) || target.Temperature < 0 || target.Temperature > 2 {
		return errors.New("temperature must be finite and between 0 and 2")
	}
	if target.MaxTokens < 0 {
		return errors.New("max_tokens must be greater than or equal to 0")
	}
	if !isFinite(target.TopP) || target.TopP < 0 || target.TopP > 1 {
		return errors.New("top_p must be finite and between 0 and 1")
	}
	if target.TimeoutSeconds < 0 {
		return errors.New("timeout_seconds must be greater than or equal to 0")
	}
	if int64(target.TimeoutSeconds) > maxExecutionTimeoutSeconds {
		return errors.New("timeout_seconds exceeds the maximum supported duration")
	}
	return nil
}

func isFinite(value float64) bool {
	return !math.IsNaN(value) && !math.IsInf(value, 0)
}