package handler

import (
	"encoding/json"
	"errors"
	"net/http"

	"github.com/gin-gonic/gin"
	"gorm.io/gorm"

	"github.com/wangjia/pay/internal/gateway"
	"github.com/wangjia/pay/internal/model"
	"github.com/wangjia/pay/internal/provider"
	"github.com/wangjia/pay/internal/util"
)

// DevMockHandler is a dev-only handler (registered only when
// config.C.MockChannelEnabled=true, see main.go) that lets local integration
// testing simulate a successful payment on the fake channel with a single
// HTTP request — no manual sqlite surgery or hand-crafted callback body needed.
type DevMockHandler struct {
	db *gorm.DB
	g  *gateway.Gateway
}

func NewDevMockHandler(db *gorm.DB, g *gateway.Gateway) *DevMockHandler {
	return &DevMockHandler{db: db, g: g}
}

// fakeCallbackBody mirrors provider/fake.Provider.VerifyCallback's expected JSON shape.
type fakeCallbackBody struct {
	ProviderRef string `json:"provider_ref"`
	Status      string `json:"status"`
	AmountMinor int64  `json:"amount_minor"`
	Currency    string `json:"currency"`
}

// MarkPaid POST /api/v2/dev/orders/:order_no/mark-paid —— dev-only「模拟付款成功」。
// 按 out_trade_no 取该单在 fake 渠道最近一次 attempt(provider_ref + amount_minor/currency),
// 原样组一个 fake 渠道回调体,内部直接走 gateway.HandleCallback("fake", ...)(与
// POST /api/v2/callback/fake 同一入口),触发 Settle→webhook 入队。金额/币种从 attempt
// 读,不由调用方传,保证与订单一致、免手工对账。
func (h *DevMockHandler) MarkPaid(c *gin.Context) {
	orderNo := c.Param("order_no")
	var att model.Attempt
	err := h.db.Where("out_trade_no = ? AND channel = ?", orderNo, "fake").
		Order("id DESC").First(&att).Error
	if errors.Is(err, gorm.ErrRecordNotFound) {
		util.RespondError(c, http.StatusNotFound, "order_not_found", "订单不存在或未走 fake 渠道下单")
		return
	}
	if err != nil {
		util.RespondError(c, http.StatusInternalServerError, "internal_error", "查询订单失败")
		return
	}

	body, err := json.Marshal(fakeCallbackBody{
		ProviderRef: att.ProviderRef, Status: "succeeded",
		AmountMinor: att.AmountMinor, Currency: att.Currency,
	})
	if err != nil {
		util.RespondError(c, http.StatusInternalServerError, "internal_error", "构造回调体失败")
		return
	}

	res, err := h.g.HandleCallback(c.Request.Context(), "fake", provider.CallbackInput{Raw: body})
	if err != nil && res != gateway.SettleAmountMismatch {
		util.RespondError(c, http.StatusInternalServerError, "mark_paid_failed", "模拟付款失败: "+err.Error())
		return
	}

	c.JSON(http.StatusOK, gin.H{"ok": true, "out_trade_no": orderNo, "result": string(res)})
}