package license

import (
	"encoding/base64"
	"encoding/json"
	"license-server/storage"
	"time"

	"github.com/gofiber/fiber/v2"
)

func GenerateLicenseHandler(db storage.Database) fiber.Handler {
	return func(c *fiber.Ctx) error {
		var req LicenseRequest
		if err := c.BodyParser(&req); err != nil {
			return fiber.NewError(fiber.StatusBadRequest, "Invalid request body")
		}

		if req.MachineID == "" {
			return fiber.NewError(fiber.StatusBadRequest, "Missing machine ID")
		}

		// ✅ 检查是否已经生成过
		if db.HasGenerated(req.MachineID) {
			return fiber.NewError(fiber.StatusForbidden, "License already generated for this machine")
		}

		// ❌ 不再接收客户端传的 Expiry，由后续激活阶段设置
		req.Expiry = ""

		payloadBytes, err := json.Marshal(req)
		if err != nil {
			return fiber.NewError(fiber.StatusInternalServerError, "Failed to encode payload")
		}

		signature, err := SignPayload(payloadBytes)
		if err != nil {
			return fiber.NewError(fiber.StatusInternalServerError, "Signing failed")
		}

		licenseFile := LicenseFile{
			Payload:   base64.StdEncoding.EncodeToString(payloadBytes),
			Signature: signature,
		}

		// ✅ 保存生成记录（避免重复）
		db.SaveGenerated(req.MachineID, licenseFile.Payload+"."+licenseFile.Signature)

		return c.JSON(licenseFile)
	}
}

func ActivateLicenseHandler(db storage.Database) fiber.Handler {
	return func(c *fiber.Ctx) error {
		var lf LicenseFile
		if err := c.BodyParser(&lf); err != nil {
			return fiber.NewError(fiber.StatusBadRequest, "Invalid license format")
		}

		payloadBytes, err := base64.StdEncoding.DecodeString(lf.Payload)
		if err != nil {
			return fiber.NewError(fiber.StatusBadRequest, "Invalid base64 payload")
		}

		if !VerifySignature(GetPublicKey(), payloadBytes, lf.Signature) {
			return fiber.NewError(fiber.StatusUnauthorized, "Invalid license signature")
		}

		var req LicenseRequest
		if err := json.Unmarshal(payloadBytes, &req); err != nil {
			return fiber.NewError(fiber.StatusBadRequest, "Malformed payload")
		}

		if req.MachineID == "" {
			return fiber.NewError(fiber.StatusBadRequest, "Missing machine ID")
		}

		if db.HasActivated(req.MachineID) {
			return fiber.NewError(fiber.StatusForbidden, "This machine is already activated")
		}

		// ✅ 设置新的 Expiry 字段（激活日起算 365 天）
		req.Expiry = time.Now().AddDate(1, 0, 0).Format("2006-01-02")

		// ✅ 重新生成 payload 和签名
		newPayload, err := json.Marshal(req)
		if err != nil {
			return fiber.NewError(fiber.StatusInternalServerError, "Failed to re-encode payload")
		}
		newSignature, err := SignPayload(newPayload)
		if err != nil {
			return fiber.NewError(fiber.StatusInternalServerError, "Signing failed")
		}

		db.SaveActivation(req.MachineID, base64.StdEncoding.EncodeToString(newPayload)+"."+newSignature)

		return c.JSON(fiber.Map{
			"status":    "success",
			"message":   "License activated successfully",
			"expiry":    req.Expiry,
			"payload":   base64.StdEncoding.EncodeToString(newPayload),
			"signature": newSignature,
		})
	}
}

func ValidateLicenseHandler(db storage.Database) fiber.Handler {
	return func(c *fiber.Ctx) error {
		var lf LicenseFile
		if err := c.BodyParser(&lf); err != nil {
			return fiber.NewError(fiber.StatusBadRequest, "Invalid license format")
		}

		payloadBytes, err := base64.StdEncoding.DecodeString(lf.Payload)
		if err != nil {
			return fiber.NewError(fiber.StatusBadRequest, "Invalid base64 payload")
		}

		if !VerifySignature(GetPublicKey(), payloadBytes, lf.Signature) {
			return fiber.NewError(fiber.StatusUnauthorized, "Invalid license signature")
		}

		var req LicenseRequest
		if err := json.Unmarshal(payloadBytes, &req); err != nil {
			return fiber.NewError(fiber.StatusBadRequest, "Malformed payload")
		}

		expiry, err := time.Parse("2006-01-02", req.Expiry)
		if err != nil || time.Now().After(expiry) {
			return fiber.NewError(fiber.StatusForbidden, "License expired")
		}

		clientMachineID := c.Get("X-Machine-ID")
		if clientMachineID == "" {
			return fiber.NewError(fiber.StatusBadRequest, "Missing machine ID in header")
		}
		if clientMachineID != req.MachineID {
			return fiber.NewError(fiber.StatusForbidden, "Machine ID mismatch")
		}

		return c.JSON(fiber.Map{
			"valid":    true,
			"features": req.Features,
			"expiry":   req.Expiry,
		})
	}
}