package invitation

import (
	"context"
	"errors"
	"net/http"
	"strconv"
	"strings"

	"hfb_sys/backend/internal/middleware"
	"hfb_sys/backend/internal/sitecode"
	"hfb_sys/backend/pkg/response"

	"github.com/gin-gonic/gin"
)

type SiteScoper interface {
	ScopeSiteID(ctx context.Context, adminID, requested uint64) (uint64, error)
}

type Handler struct {
	service    *Service
	siteScoper SiteScoper
}

func NewHandler(service *Service) *Handler {
	return &Handler{service: service}
}

func (h *Handler) SetSiteScoper(scoper SiteScoper) {
	h.siteScoper = scoper
}

// GetInviteInfo 公开接口：根据邀请码查询邀请人简要信息（用于落地注册页）
func (h *Handler) GetInviteInfo(c *gin.Context) {
	code := strings.TrimSpace(c.Param("code"))
	if code == "" {
		code = strings.TrimSpace(c.Query("code"))
	}
	info, err := h.service.GetInviteCodeInfo(c.Request.Context(), code)
	if err != nil {
		writeInvitationError(c, err)
		return
	}
	response.OK(c, info)
}

// UserSummary 个人中心邀请返利概览
func (h *Handler) UserSummary(c *gin.Context) {
	userID, ok := currentUserID(c)
	if !ok {
		response.Unauthorized(c, "缺少用户上下文")
		return
	}
	siteID := parseSiteID(c)
	summary, err := h.service.GetUserSummary(c.Request.Context(), userID, siteID)
	if err != nil {
		writeInvitationError(c, err)
		return
	}
	response.OK(c, summary)
}

// ListMyInvitedUsers 我的邀请好友列表
func (h *Handler) ListMyInvitedUsers(c *gin.Context) {
	userID, ok := currentUserID(c)
	if !ok {
		response.Unauthorized(c, "缺少用户上下文")
		return
	}
	page, pageSize := parsePagination(c)
	items, total, err := h.service.ListMyInvitedUsers(c.Request.Context(), userID, page, pageSize)
	if err != nil {
		writeInvitationError(c, err)
		return
	}
	response.OK(c, gin.H{
		"items":     items,
		"total":     total,
		"page":      page,
		"page_size": pageSize,
	})
}

// ListMyRebates 我的返利流水
func (h *Handler) ListMyRebates(c *gin.Context) {
	userID, ok := currentUserID(c)
	if !ok {
		response.Unauthorized(c, "缺少用户上下文")
		return
	}
	page, pageSize := parsePagination(c)
	items, total, err := h.service.ListMyRebates(c.Request.Context(), userID, page, pageSize)
	if err != nil {
		writeInvitationError(c, err)
		return
	}
	response.OK(c, gin.H{
		"items":     items,
		"total":     total,
		"page":      page,
		"page_size": pageSize,
	})
}

// AdminGetConfig 管理员获取返利比例配置
func (h *Handler) AdminGetConfig(c *gin.Context) {
	siteID := parseAdminSiteID(c)
	cfg, err := h.service.GetRebateConfig(c.Request.Context(), siteID)
	if err != nil {
		writeInvitationError(c, err)
		return
	}
	response.OK(c, cfg)
}

// AdminUpdateConfig 管理员更新返利比例配置
func (h *Handler) AdminUpdateConfig(c *gin.Context) {
	siteID := parseAdminSiteID(c)
	var req UpdateConfigRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		response.BadRequest(c, "比例参数格式不正确，必须在0到1之间")
		return
	}
	cfg, err := h.service.UpdateRebateConfig(c.Request.Context(), siteID, req)
	if err != nil {
		writeInvitationError(c, err)
		return
	}
	response.OK(c, cfg)
}

// AdminInvitations 管理员查询全量邀请关系
func (h *Handler) AdminInvitations(c *gin.Context) {
	var query AdminInvitationQuery
	if err := c.ShouldBindQuery(&query); err != nil {
		response.BadRequest(c, "查询参数不正确")
		return
	}
	items, total, err := h.service.ListAdminInvitations(c.Request.Context(), query)
	if err != nil {
		writeInvitationError(c, err)
		return
	}
	response.OK(c, gin.H{
		"items":     items,
		"total":     total,
		"page":      query.Page,
		"page_size": query.PageSize,
	})
}

// AdminRebates 管理员查询全量返利流水
func (h *Handler) AdminRebates(c *gin.Context) {
	var query AdminRebateLedgerQuery
	if err := c.ShouldBindQuery(&query); err != nil {
		response.BadRequest(c, "查询参数不正确")
		return
	}
	items, total, err := h.service.ListAdminRebateLedgers(c.Request.Context(), query)
	if err != nil {
		writeInvitationError(c, err)
		return
	}
	response.OK(c, gin.H{
		"items":     items,
		"total":     total,
		"page":      query.Page,
		"page_size": query.PageSize,
	})
}

// AdminRebateSummary 管理员查看返利统计汇总
func (h *Handler) AdminRebateSummary(c *gin.Context) {
	var query AdminRebateLedgerQuery
	if err := c.ShouldBindQuery(&query); err != nil {
		response.BadRequest(c, "查询参数不正确")
		return
	}
	summary, err := h.service.AdminRebateSummary(c.Request.Context(), query)
	if err != nil {
		writeInvitationError(c, err)
		return
	}
	response.OK(c, summary)
}

func currentUserID(c *gin.Context) (uint64, bool) {
	value, ok := c.Get(middleware.ContextUserID)
	if !ok {
		return 0, false
	}
	userID, ok := value.(uint64)
	return userID, ok
}

func parsePagination(c *gin.Context) (int, int) {
	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
	pageSize, _ := strconv.Atoi(c.DefaultQuery("page_size", "20"))
	if page < 1 {
		page = 1
	}
	if pageSize < 1 {
		pageSize = 20
	}
	if pageSize > 100 {
		pageSize = 100
	}
	return page, pageSize
}

func parseSiteID(c *gin.Context) uint64 {
	siteCode := sitecode.FromRequest(c)
	if strings.TrimSpace(siteCode) == "" {
		return 0
	}
	// 可从上下文或按 siteCode 获取 siteID
	return 0
}

func parseAdminSiteID(c *gin.Context) uint64 {
	raw := c.Query("distribution_site_id")
	if raw == "" {
		raw = c.Param("id")
	}
	if raw == "" {
		raw = c.Param("site_id")
	}
	if raw != "" {
		id, _ := strconv.ParseUint(raw, 10, 64)
		return id
	}
	return 0
}

func writeInvitationError(c *gin.Context, err error) {
	response.RecordError(c, err)
	switch {
	case errors.Is(err, ErrDependencyUnavailable):
		response.ServiceUnavailable(c, "数据库服务不可用")
	case errors.Is(err, ErrInvalidInviteCode):
		response.BadRequest(c, "邀请码不存在或无效")
	case errors.Is(err, ErrSelfInviteNotAllowed):
		response.BadRequest(c, "不能自己邀请自己")
	case errors.Is(err, ErrAlreadyInvited):
		response.BadRequest(c, "用户已绑定过邀请人")
	case errors.Is(err, ErrInviterNotVerified):
		response.BadRequest(c, "邀请人尚未完成实名认证")
	default:
		response.Error(c, http.StatusInternalServerError, "invitation_error", err.Error())
	}
}

// DistributionGetConfig 分销端获取本站邀请返利比例配置
func (h *Handler) DistributionGetConfig(c *gin.Context) {
	siteID, err := h.resolveDistributionSiteID(c)
	if err != nil {
		response.Forbidden(c, "无权访问该分销站点")
		return
	}
	cfg, err := h.service.GetRebateConfig(c.Request.Context(), siteID)
	if err != nil {
		writeInvitationError(c, err)
		return
	}
	response.OK(c, cfg)
}

// DistributionUpdateConfig 分销端更新本站邀请返利比例配置
func (h *Handler) DistributionUpdateConfig(c *gin.Context) {
	siteID, err := h.resolveDistributionSiteID(c)
	if err != nil {
		response.Forbidden(c, "无权操作该分销站点")
		return
	}
	if siteID == 0 {
		response.BadRequest(c, "未指定有效分销站点")
		return
	}
	var req UpdateConfigRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		response.BadRequest(c, "比例参数格式不正确，必须在0到1之间")
		return
	}
	cfg, err := h.service.UpdateRebateConfig(c.Request.Context(), siteID, req)
	if err != nil {
		writeInvitationError(c, err)
		return
	}
	response.OK(c, cfg)
}

// DistributionListInvitations 分销端查看本站邀请关系
func (h *Handler) DistributionListInvitations(c *gin.Context) {
	siteID, err := h.resolveDistributionSiteID(c)
	if err != nil {
		response.Forbidden(c, "无权访问该分销站点")
		return
	}
	var query AdminInvitationQuery
	if err := c.ShouldBindQuery(&query); err != nil {
		response.BadRequest(c, "查询参数不正确")
		return
	}
	query.DistributionSiteID = &siteID
	items, total, err := h.service.ListAdminInvitations(c.Request.Context(), query)
	if err != nil {
		writeInvitationError(c, err)
		return
	}
	response.OK(c, gin.H{
		"items":     items,
		"total":     total,
		"page":      query.Page,
		"page_size": query.PageSize,
	})
}

// DistributionListRebates 分销端查看本站返利支出流水
func (h *Handler) DistributionListRebates(c *gin.Context) {
	siteID, err := h.resolveDistributionSiteID(c)
	if err != nil {
		response.Forbidden(c, "无权访问该分销站点")
		return
	}
	var query AdminRebateLedgerQuery
	if err := c.ShouldBindQuery(&query); err != nil {
		response.BadRequest(c, "查询参数不正确")
		return
	}
	query.DistributionSiteID = &siteID
	items, total, err := h.service.ListAdminRebateLedgers(c.Request.Context(), query)
	if err != nil {
		writeInvitationError(c, err)
		return
	}
	response.OK(c, gin.H{
		"items":     items,
		"total":     total,
		"page":      query.Page,
		"page_size": query.PageSize,
	})
}

func (h *Handler) resolveDistributionSiteID(c *gin.Context) (uint64, error) {
	adminID, _ := currentAdminID(c)
	var requested uint64
	if raw := c.Param("id"); raw != "" {
		if id, err := strconv.ParseUint(raw, 10, 64); err == nil && id > 0 {
			requested = id
		}
	}
	if requested == 0 {
		if raw := c.Query("site_id"); raw != "" {
			if id, err := strconv.ParseUint(raw, 10, 64); err == nil && id > 0 {
				requested = id
			}
		}
	}
	if requested == 0 {
		if raw := c.Query("distribution_site_id"); raw != "" {
			if id, err := strconv.ParseUint(raw, 10, 64); err == nil && id > 0 {
				requested = id
			}
		}
	}
	if h.siteScoper != nil {
		return h.siteScoper.ScopeSiteID(c.Request.Context(), adminID, requested)
	}
	return requested, nil
}

func currentAdminID(c *gin.Context) (uint64, bool) {
	value, ok := c.Get(middleware.ContextAdminID)
	if !ok {
		return 0, false
	}
	adminID, ok := value.(uint64)
	return adminID, ok
}