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 == "" || req.Expiry == "" {
			return fiber.NewError(fiber.StatusBadRequest, "Missing required fields")
		}

		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,
		}

		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")
		}

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

		// 绑定激活记录
		db.SaveActivation(req.MachineID, lf.Payload+"."+lf.Signature)

		return c.JSON(fiber.Map{"status": "success", "message": "License activated successfully"})
	}
}

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")
		}

		// 1. 校验签名
		if !VerifySignature(GetPublicKey(), payloadBytes, lf.Signature) {
			return fiber.NewError(fiber.StatusUnauthorized, "Invalid license signature")
		}

		// 2. 解析 payload
		var req LicenseRequest
		if err := json.Unmarshal(payloadBytes, &req); err != nil {
			return fiber.NewError(fiber.StatusBadRequest, "Malformed payload")
		}

		// 3. 验证是否过期
		expiry, err := time.Parse("2006-01-02", req.Expiry)
		if err != nil || time.Now().After(expiry) {
			return fiber.NewError(fiber.StatusForbidden, "License expired")
		}

		// ✅ 4. 关键补充：校验调用者的 MachineID 与 license 中一致
		// 从请求 Header 或 Body 读取实际设备 ID（假设从 Header 传）
		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,
			//	"machine":  req.MachineID,
			"expiry": req.Expiry,
		})
	}
}