package api

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

	"github.com/gin-gonic/gin"

	"ws_usernode/internal/config"
	"ws_usernode/internal/model"
	"ws_usernode/internal/service"
)

// ApprovalHandler 新账号申请与审批接口（PLAN F4）：
// 公开提交（POST /approvals）、管理员列表（GET /approvals）、审批（POST /approvals/:id/review）。
type ApprovalHandler struct {
	svc *service.ApprovalService
	cfg *config.Config
	h   *Handler // 访问审计 helper
}

// ApprovalSubmitRequest 提交申请（用户名不含 ext_ 前缀）。
type ApprovalSubmitRequest struct {
	Username   string `json:"username" binding:"required"`
	Email      string `json:"email" binding:"required"`
	Supervisor string `json:"supervisor"`
	Purpose    string `json:"purpose"`
}

// Submit POST /approvals —— 公开提交新账号申请。
func (h *ApprovalHandler) Submit(c *gin.Context) {
	var req ApprovalSubmitRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		fail(c, http.StatusBadRequest, "请求参数不合法: "+err.Error())
		return
	}
	a, err := h.svc.Submit(c.Request.Context(), req.Username, req.Email, req.Supervisor, req.Purpose)
	if err != nil {
		h.h.audit(c, "approval.submit", "approval", "", map[string]any{"username": req.Username, "err": err.Error()}, model.ResultFailed)
		switch {
		case errors.Is(err, service.ErrUsernameTaken):
			fail(c, http.StatusConflict, err.Error())
		default:
			fail(c, http.StatusBadRequest, err.Error())
		}
		return
	}
	h.h.audit(c, "approval.submit", "approval", strconv.FormatUint(uint64(a.ID), 10), map[string]any{"username": a.UsernameRequested}, model.ResultSuccess)
	ok(c, a)
}

// List GET /approvals —— 申请单列表（admin），按状态筛选。
func (h *ApprovalHandler) List(c *gin.Context) {
	rows, err := h.svc.List(c.Request.Context(), c.Query("status"))
	if err != nil {
		fail(c, http.StatusInternalServerError, err.Error())
		return
	}
	ok(c, gin.H{"items": rows})
}

// ApprovalReviewRequest 审批请求：通过 → approve=true；拒绝 → approve=false + 理由。
type ApprovalReviewRequest struct {
	Approve bool   `json:"approve"`
	Reason  string `json:"reason"`
}

// Review POST /approvals/:id/review —— 审批（通过 → 自动建号 / 拒绝 + 理由）。
func (h *ApprovalHandler) Review(c *gin.Context) {
	id, err := strconv.ParseUint(c.Param("id"), 10, 64)
	if err != nil {
		fail(c, http.StatusBadRequest, "无效的申请单 ID")
		return
	}
	var req ApprovalReviewRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		fail(c, http.StatusBadRequest, "请求参数不合法: "+err.Error())
		return
	}
	reviewerID := uint(0)
	if sess := sessionFrom(c); sess != nil {
		reviewerID = sess.RefID
	}
	a, err := h.svc.Review(c.Request.Context(), uint(id), req.Approve, reviewerID, req.Reason)
	if err != nil {
		h.h.audit(c, "approval.review", "approval", c.Param("id"), map[string]any{"approve": req.Approve, "err": err.Error()}, model.ResultFailed)
		switch {
		case errors.Is(err, service.ErrApprovalNotFound):
			fail(c, http.StatusNotFound, err.Error())
		case errors.Is(err, service.ErrApprovalReviewed):
			fail(c, http.StatusConflict, err.Error())
		case errors.Is(err, service.ErrReasonRequired):
			fail(c, http.StatusBadRequest, err.Error())
		case errors.Is(err, service.ErrUsernameTaken):
			fail(c, http.StatusConflict, err.Error())
		default:
			fail(c, http.StatusInternalServerError, err.Error())
		}
		return
	}
	h.h.audit(c, "approval.review", "approval", c.Param("id"), map[string]any{"approve": req.Approve, "reason": req.Reason, "status": a.Status}, model.ResultSuccess)
	ok(c, a)
}