package billing

import (
	"errors"
	"math"
	"strings"
)

const Seedream50ProModel = "doubao-seedream-5-0-pro-260628"

const SeedreamLayerPixelThreshold = 2_610_000

type SeedreamLayerImage struct {
	Width  int
	Height int
}

// CalculateSeedreamAmountFen applies Seedream's additive input-image price
// before the platform markup: the first reference image is free and every
// additional reference image costs 2 fen.
func CalculateSeedreamAmountFen(outputPriceFen int64, referenceImageCount int, markupMultiplier float64) (int64, error) {
	if outputPriceFen <= 0 {
		return 0, errors.New("seedream output price must be positive")
	}
	if referenceImageCount < 0 || referenceImageCount > 10 {
		return 0, errors.New("seedream reference image count must be between 0 and 10")
	}
	if math.IsNaN(markupMultiplier) || math.IsInf(markupMultiplier, 0) || markupMultiplier < 1 {
		return 0, errors.New("seedream markup multiplier must be at least 1")
	}
	extraInputPriceFen := int64(max(0, referenceImageCount-1) * 2)
	return int64(math.Ceil(float64(outputPriceFen+extraInputPriceFen) * markupMultiplier)), nil
}

func IsSeedreamBillingModel(model string) bool {
	return strings.TrimSpace(model) == Seedream50ProModel
}

// CalculateSeedreamLayerAmountFen charges every returned image independently:
// 15 fen up to 2.61M pixels and 30 fen above that tier, followed by markup.
func CalculateSeedreamLayerAmountFen(images []SeedreamLayerImage, markupMultiplier float64) (int64, error) {
	if len(images) == 0 || len(images) > 17 {
		return 0, errors.New("seedream layer output count must be between 1 and 17")
	}
	if math.IsNaN(markupMultiplier) || math.IsInf(markupMultiplier, 0) || markupMultiplier < 1 {
		return 0, errors.New("seedream markup multiplier must be at least 1")
	}
	standardAmountFen := int64(0)
	for _, image := range images {
		if image.Width <= 0 || image.Height <= 0 {
			return 0, errors.New("seedream layer output dimensions must be positive")
		}
		price := int64(15)
		if int64(image.Width)*int64(image.Height) > SeedreamLayerPixelThreshold {
			price = 30
		}
		standardAmountFen += price
	}
	return int64(math.Ceil(float64(standardAmountFen) * markupMultiplier)), nil
}