package handler

import (
	"log/slog"
	"net/http"
	"time"

	"github.com/gin-gonic/gin"

	"github.com/dhao2001/mygo/internal/api"
	"github.com/dhao2001/mygo/internal/model"
	"github.com/dhao2001/mygo/internal/service"
)

// AuthHandler handles authentication endpoints.
type AuthHandler struct {
	authService *service.AuthService
}

// NewAuthHandler creates an AuthHandler.
func NewAuthHandler(authService *service.AuthService) *AuthHandler {
	return &AuthHandler{authService: authService}
}

type registerRequest struct {
	Username string `json:"username" binding:"required"`
	Email    string `json:"email" binding:"required,email"`
	Password string `json:"password" binding:"required,min=6"`
}

type loginRequest struct {
	Email    string `json:"email" binding:"required,email"`
	Password string `json:"password" binding:"required"`
}

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

type userResponse struct {
	ID        string    `json:"id"`
	Username  string    `json:"username"`
	Email     string    `json:"email"`
	IsAdmin   bool      `json:"is_admin"`
	CreatedAt time.Time `json:"created_at"`
	UpdatedAt time.Time `json:"updated_at"`
}

type tokenPairResponse struct {
	AccessToken  string `json:"access_token"`
	RefreshToken string `json:"refresh_token"`
}

// Register handles POST /api/v1/auth/register.
func (h *AuthHandler) Register(c *gin.Context) {
	var req registerRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		slog.DebugContext(c.Request.Context(), "register bind failed", "error", err)
		api.Error(c, http.StatusBadRequest, "invalid request body")
		return
	}

	user, err := h.authService.Register(c.Request.Context(), req.Username, req.Email, req.Password)
	if err != nil {
		api.RespondError(c, err)
		return
	}

	c.JSON(http.StatusCreated, toUserResponse(user))
}

// Login handles POST /api/v1/auth/login.
func (h *AuthHandler) Login(c *gin.Context) {
	var req loginRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		slog.DebugContext(c.Request.Context(), "login bind failed", "error", err)
		api.Error(c, http.StatusBadRequest, "invalid request body")
		return
	}

	pair, err := h.authService.Login(c.Request.Context(), req.Email, req.Password)
	if err != nil {
		api.RespondError(c, err)
		return
	}

	c.JSON(http.StatusOK, toTokenPairResponse(pair))
}

// Refresh handles POST /api/v1/auth/refresh.
func (h *AuthHandler) Refresh(c *gin.Context) {
	var req tokenRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		slog.DebugContext(c.Request.Context(), "refresh bind failed", "error", err)
		api.Error(c, http.StatusBadRequest, "invalid request body")
		return
	}

	pair, err := h.authService.Refresh(c.Request.Context(), req.RefreshToken)
	if err != nil {
		api.RespondError(c, err)
		return
	}

	c.JSON(http.StatusOK, toTokenPairResponse(pair))
}

// Logout handles POST /api/v1/auth/logout.
func (h *AuthHandler) Logout(c *gin.Context) {
	var req tokenRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		slog.DebugContext(c.Request.Context(), "logout bind failed", "error", err)
		api.Error(c, http.StatusBadRequest, "invalid request body")
		return
	}

	if err := h.authService.Logout(c.Request.Context(), req.RefreshToken); err != nil {
		api.RespondError(c, err)
		return
	}

	c.Status(http.StatusOK)
}

func toUserResponse(user *model.User) userResponse {
	return userResponse{
		ID:        user.ID,
		Username:  user.Username,
		Email:     user.Email,
		IsAdmin:   user.IsAdmin,
		CreatedAt: user.CreatedAt,
		UpdatedAt: user.UpdatedAt,
	}
}

func toTokenPairResponse(pair *service.TokenPair) tokenPairResponse {
	return tokenPairResponse{
		AccessToken:  pair.AccessToken,
		RefreshToken: pair.RefreshToken,
	}
}