package handlers

import (
	"errors"
	"net/http"
	"time"

	"github.com/gin-gonic/gin"
	"github.com/jackc/pgx/v5"

	"booklib/internal/auth"
)

const loginWindow = time.Minute
const loginMax = 5

func (h *H) Login(c *gin.Context) {
	var req struct{ Username, Password string }
	if c.ShouldBindJSON(&req) != nil || req.Username == "" || req.Password == "" {
		err(c, http.StatusBadRequest, "bad_request", "username and password required")
		return
	}
	if n := h.rdb.IncrWindow(c, "loginrl:"+c.ClientIP(), loginWindow); n > loginMax {
		err(c, http.StatusTooManyRequests, "rate_limited", "too many login attempts")
		return
	}
	u, qerr := h.st.GetUserByName(c, req.Username)
	if qerr != nil {
		if !errors.Is(qerr, pgx.ErrNoRows) {
			dbErr(c, qerr)
			return
		}
		// 用户不存在也走一次 bcrypt，防用户名枚举时序差
		auth.CheckPassword("$2a$12$V5TmlpkEi9G/DFAmnkt9YunNdGLnnW921/5TcSo4OeE6iaaLDPN1K", req.Password)
		err(c, http.StatusUnauthorized, "unauthorized", "bad credentials")
		return
	}
	if !auth.CheckPassword(u.PasswordHash, req.Password) {
		err(c, http.StatusUnauthorized, "unauthorized", "bad credentials")
		return
	}
	tok, serr := auth.Sign(h.cfg.JWTSecret, u.ID, u.Role)
	if serr != nil {
		err(c, http.StatusInternalServerError, "internal", "sign")
		return
	}
	c.JSON(http.StatusOK, gin.H{"token": tok})
}

func (h *H) Me(c *gin.Context) {
	// B7: only no-rows → 401; other errors (PG down) go through dbErr → 503.
	u, qerr := h.st.GetUserByID(c, uid(c))
	if qerr != nil {
		if errors.Is(qerr, pgx.ErrNoRows) {
			err(c, http.StatusUnauthorized, "unauthorized", "no such user")
			return
		}
		dbErr(c, qerr)
		return
	}
	c.JSON(http.StatusOK, gin.H{"id": u.ID, "username": u.Username, "role": u.Role})
}