package api

import (
	"database/sql"
	"fmt"
	"net/http"
	"time"

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

type renewAccessRequest struct {
	RefreshToken string `json:"refresh_token" binding:"required"`
}

type renewAccessResponse struct {
	AccesToken           string    `json:"access_token"`
	AccessTokenExpiresAt time.Time `json:"access_token_expires_at"`
}

func (server *Server) renewAccessToken(ctx *gin.Context) {
	var req renewAccessRequest
	if err := ctx.ShouldBindJSON(&req); err != nil {
		ctx.JSON(http.StatusBadRequest, ErrorResponse(err, ""))
		return
	}

	refreshPayload, err := server.TokenMaker.VerifyToken(req.RefreshToken)
	if err != nil {
		ctx.JSON(http.StatusUnauthorized, ErrorResponse(err, ""))
		return
	}

	session, err := server.Store.GetSession(ctx, int32(refreshPayload.UserID))
	if err != nil {
		if err == sql.ErrNoRows {
			ctx.JSON(http.StatusNotFound, ErrorResponse(err, ""))
			return
		}
		ctx.JSON(http.StatusInternalServerError, ErrorResponse(err, ""))
		return
	}

	if session.IsBlocked {
		err := fmt.Errorf("blocked session")
		ctx.JSON(http.StatusUnauthorized, ErrorResponse(err, ""))
		return
	}

	if session.Username != refreshPayload.Username {
		err := fmt.Errorf("incorrect session user")
		ctx.JSON(http.StatusUnauthorized, ErrorResponse(err, ""))
		return
	}

	if session.RefreshToken != req.RefreshToken {
		err := fmt.Errorf("mismatched session token")
		ctx.JSON(http.StatusUnauthorized, ErrorResponse(err, ""))
		return
	}

	if time.Now().After(refreshPayload.ExpiredAt) {
		err := fmt.Errorf("expired session")
		ctx.JSON(http.StatusUnauthorized, ErrorResponse(err, ""))
		return
	}

	user, err := server.Store.GetUser(ctx, refreshPayload.Username)
	if err != nil {
		if err == sql.ErrNoRows {
			ctx.JSON(http.StatusNotFound, ErrorResponse(err, ""))
			return
		}
		ctx.JSON(http.StatusInternalServerError, ErrorResponse(err, ""))
		return
	}

	accessToken, accessPayload, err := server.TokenMaker.CreateToken(
		refreshPayload.Username,
		int(user.ID),
		server.Config.TokenDuration,
	)

	if err != nil {
		ctx.JSON(http.StatusInternalServerError, ErrorResponse(err, ""))
		return
	}

	res := renewAccessResponse{
		AccesToken:           accessToken,
		AccessTokenExpiresAt: accessPayload.ExpiredAt,
	}

	ctx.JSON(http.StatusOK, res)
}