package handler

import (
	"context"
	"io"
	"net/http"
	"path/filepath"
	"strconv"

	"github.com/gin-gonic/gin"
	"pay-bridge/internal/channel"
	"pay-bridge/internal/errcode"
	"pay-bridge/internal/model"
)

// merchantService 定义 MerchantHandler 依赖的 service 方法，便于测试时注入 mock
type merchantService interface {
	CreateMerchantForApp(ctx context.Context, appID string, m *model.Merchant) error
	GetMerchantForApp(ctx context.Context, appID, merchantID string) (*model.Merchant, error)
	ListMerchantsForApp(ctx context.Context, appID string, status model.MerchantStatus, limit, offset int) ([]*model.Merchant, error)
	ApplyForApp(ctx context.Context, appID, merchantID, channelCode string, bizContent map[string]any) (string, error)
	QueryAuditStatusForApp(ctx context.Context, appID, merchantID string) (*model.MerchantApplication, error)
	UploadFile(ctx context.Context, channelCode string, req *channel.UploadFileReq) (string, error)
}

// MerchantHandler 业务侧商户进件接口处理器（HMAC 鉴权，appID 隔离）
type MerchantHandler struct {
	merchantSvc merchantService
}

func NewMerchantHandler(svc merchantService) *MerchantHandler {
	return &MerchantHandler{merchantSvc: svc}
}

// --- 请求结构体 ---

type createMerchantReq struct {
	MerchantID   string `json:"merchant_id" binding:"required"`
	MerchantName string `json:"merchant_name" binding:"required"`
	LicenseNo    string `json:"license_no"`
	LegalPerson  string `json:"legal_person"`
	BankAccount  string `json:"bank_account"`
}

type merchantApplyReq struct {
	ChannelCode string         `json:"channel_code" binding:"required"`
	SubmitData  map[string]any `json:"submit_data"`
}

// --- Handlers ---

// CreateMerchant POST /api/v1/merchant
func (h *MerchantHandler) CreateMerchant(c *gin.Context) {
	var req createMerchantReq
	if err := c.ShouldBindJSON(&req); err != nil {
		BadRequest(c, errcode.ErrInvalidParam, err.Error())
		return
	}

	appID := c.GetString("app_id")
	m := &model.Merchant{
		MerchantID:   req.MerchantID,
		MerchantName: req.MerchantName,
		LicenseNo:    req.LicenseNo,
		LegalPerson:  req.LegalPerson,
		BankAccount:  req.BankAccount,
	}
	if err := h.merchantSvc.CreateMerchantForApp(c.Request.Context(), appID, m); err != nil {
		InternalError(c, errcode.ErrInternalDB, err.Error())
		return
	}
	OK(c, gin.H{"merchant_id": m.MerchantID})
}

// ListMerchants GET /api/v1/merchant
func (h *MerchantHandler) ListMerchants(c *gin.Context) {
	appID := c.GetString("app_id")
	status := model.MerchantStatus(c.Query("status"))
	limit, _ := strconv.Atoi(c.DefaultQuery("limit", "20"))
	offset, _ := strconv.Atoi(c.DefaultQuery("offset", "0"))

	merchants, err := h.merchantSvc.ListMerchantsForApp(c.Request.Context(), appID, status, limit, offset)
	if err != nil {
		InternalError(c, errcode.ErrInternalDB, err.Error())
		return
	}
	OK(c, gin.H{"list": merchants, "limit": limit, "offset": offset})
}

// GetMerchant GET /api/v1/merchant/:merchantID
func (h *MerchantHandler) GetMerchant(c *gin.Context) {
	appID := c.GetString("app_id")
	merchantID := c.Param("merchantID")

	m, err := h.merchantSvc.GetMerchantForApp(c.Request.Context(), appID, merchantID)
	if err != nil {
		if err.Error() == errcode.ErrOrderNotFound {
			c.JSON(http.StatusNotFound, Response{Code: errcode.ErrOrderNotFound, Message: "merchant not found"})
			return
		}
		InternalError(c, errcode.ErrInternalDB, err.Error())
		return
	}
	OK(c, m)
}

// UploadFile POST /api/v1/merchant/upload-file
func (h *MerchantHandler) UploadFile(c *gin.Context) {
	channelCode := c.PostForm("channel_code")
	if channelCode == "" {
		channelCode = "HEEPAY"
	}
	fileMediaType := c.PostForm("file_media_type")
	if fileMediaType == "" {
		BadRequest(c, errcode.ErrInvalidParam, "file_media_type is required")
		return
	}

	fileHeader, err := c.FormFile("file")
	if err != nil {
		BadRequest(c, errcode.ErrInvalidParam, "file is required: "+err.Error())
		return
	}

	f, err := fileHeader.Open()
	if err != nil {
		InternalError(c, errcode.ErrInternalSystem, "open file: "+err.Error())
		return
	}
	defer f.Close()

	content, err := io.ReadAll(f)
	if err != nil {
		InternalError(c, errcode.ErrInternalSystem, "read file: "+err.Error())
		return
	}

	fileID, err := h.merchantSvc.UploadFile(c.Request.Context(), channelCode, &channel.UploadFileReq{
		FileContent:   content,
		FileName:      filepath.Base(fileHeader.Filename),
		FileMediaType: fileMediaType,
	})
	if err != nil {
		InternalError(c, errcode.ErrInternalSystem, err.Error())
		return
	}
	OK(c, gin.H{"file_id": fileID})
}

// Apply POST /api/v1/merchant/:merchantID/apply
func (h *MerchantHandler) Apply(c *gin.Context) {
	appID := c.GetString("app_id")
	merchantID := c.Param("merchantID")

	var req merchantApplyReq
	if err := c.ShouldBindJSON(&req); err != nil {
		BadRequest(c, errcode.ErrInvalidParam, err.Error())
		return
	}

	applicationID, err := h.merchantSvc.ApplyForApp(c.Request.Context(), appID, merchantID, req.ChannelCode, req.SubmitData)
	if err != nil {
		if err.Error() == errcode.ErrOrderNotFound {
			c.JSON(http.StatusNotFound, Response{Code: errcode.ErrOrderNotFound, Message: "merchant not found"})
			return
		}
		InternalError(c, errcode.ErrInternalSystem, err.Error())
		return
	}
	OK(c, gin.H{"application_id": applicationID})
}

// QueryAuditStatus GET /api/v1/merchant/:merchantID/audit
func (h *MerchantHandler) QueryAuditStatus(c *gin.Context) {
	appID := c.GetString("app_id")
	merchantID := c.Param("merchantID")

	app, err := h.merchantSvc.QueryAuditStatusForApp(c.Request.Context(), appID, merchantID)
	if err != nil {
		if err.Error() == errcode.ErrOrderNotFound {
			c.JSON(http.StatusNotFound, Response{Code: errcode.ErrOrderNotFound, Message: "merchant not found"})
			return
		}
		InternalError(c, errcode.ErrInternalSystem, err.Error())
		return
	}
	OK(c, app)
}