package handlers

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

	"github.com/go-chi/chi/v5"

	"trade/web/internal/auth"
	"trade/web/internal/middleware"
	"trade/web/internal/store"
)

type createUserReq struct {
	Username string `json:"username"`
	Password string `json:"password"`
	Role     string `json:"role"`
}

type patchUserReq struct {
	Password *string `json:"password,omitempty"`
	Disabled *bool   `json:"disabled,omitempty"`
}

func (d *Deps) AdminListUsers(w http.ResponseWriter, r *http.Request) {
	users, err := d.Auth.ListUsers()
	if err != nil {
		writeErr(w, http.StatusInternalServerError, err.Error())
		return
	}
	out := make([]map[string]any, 0, len(users))
	for i := range users {
		out = append(out, sanitize(&users[i]))
	}
	writeJSON(w, http.StatusOK, out)
}

func (d *Deps) AdminCreateUser(w http.ResponseWriter, r *http.Request) {
	var req createUserReq
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeErr(w, http.StatusBadRequest, "invalid json")
		return
	}
	req.Username = strings.TrimSpace(req.Username)
	if req.Username == "" || len(req.Password) < 6 {
		writeErr(w, http.StatusBadRequest, "用户名必填,密码至少 6 位")
		return
	}
	role := strings.TrimSpace(req.Role)
	if role == "" {
		role = store.RoleUser
	}
	if role != store.RoleAdmin && role != store.RoleUser {
		writeErr(w, http.StatusBadRequest, "role 取值必须是 admin 或 user")
		return
	}
	hash, err := auth.HashPassword(req.Password)
	if err != nil {
		writeErr(w, http.StatusInternalServerError, "hash failed")
		return
	}
	u, err := d.Auth.CreateUser(req.Username, hash, role)
	if err != nil {
		// UNIQUE 冲突等
		writeErr(w, http.StatusBadRequest, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, sanitize(u))
}

func (d *Deps) AdminPatchUser(w http.ResponseWriter, r *http.Request) {
	id, err := strconv.ParseInt(chi.URLParam(r, "id"), 10, 64)
	if err != nil {
		writeErr(w, http.StatusBadRequest, "invalid id")
		return
	}
	var req patchUserReq
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeErr(w, http.StatusBadRequest, "invalid json")
		return
	}
	if req.Password == nil && req.Disabled == nil {
		writeErr(w, http.StatusBadRequest, "无可更新字段")
		return
	}
	if req.Password != nil {
		if len(*req.Password) < 6 {
			writeErr(w, http.StatusBadRequest, "新密码至少 6 位")
			return
		}
		hash, err := auth.HashPassword(*req.Password)
		if err != nil {
			writeErr(w, http.StatusInternalServerError, "hash failed")
			return
		}
		if err := d.Auth.UpdatePassword(id, hash); err != nil {
			writeErr(w, statusForErr(err), err.Error())
			return
		}
	}
	if req.Disabled != nil {
		// 禁止禁用自己,避免管理员锁死自己
		me, _ := middleware.FromContext(r.Context())
		if *req.Disabled && me.ID == id {
			writeErr(w, http.StatusBadRequest, "不能禁用自己")
			return
		}
		if err := d.Auth.SetDisabled(id, *req.Disabled); err != nil {
			writeErr(w, statusForErr(err), err.Error())
			return
		}
	}
	u, err := d.Auth.GetByID(id)
	if err != nil {
		writeErr(w, statusForErr(err), err.Error())
		return
	}
	writeJSON(w, http.StatusOK, sanitize(u))
}

func (d *Deps) AdminDeleteUser(w http.ResponseWriter, r *http.Request) {
	id, err := strconv.ParseInt(chi.URLParam(r, "id"), 10, 64)
	if err != nil {
		writeErr(w, http.StatusBadRequest, "invalid id")
		return
	}
	me, _ := middleware.FromContext(r.Context())
	if me.ID == id {
		writeErr(w, http.StatusBadRequest, "不能删除自己")
		return
	}
	if err := d.Auth.DeleteUser(id); err != nil {
		writeErr(w, statusForErr(err), err.Error())
		return
	}
	writeJSON(w, http.StatusOK, map[string]string{"status": "ok"})
}

func statusForErr(err error) int {
	if errors.Is(err, store.ErrNotFound) {
		return http.StatusNotFound
	}
	return http.StatusInternalServerError
}