package users

import (
	"errors"
	"net/http"

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

type Handler struct {
	service *Service
}

func NewHandler(service *Service) *Handler {
	return &Handler{service: service}
}

type userResponse struct {
	ID       uuid.UUID `json:"id"`
	Username string    `json:"username"`
	Role     string    `json:"role"`
	IsActive bool      `json:"is_active"`
}

func toResponse(u *User) userResponse {
	return userResponse{ID: u.ID, Username: u.Username, Role: u.Role, IsActive: u.IsActive}
}

func (h *Handler) List(c *gin.Context) {
	list, err := h.service.List(c.Request.Context())
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to list users"})
		return
	}
	resp := make([]userResponse, 0, len(list))
	for _, u := range list {
		resp = append(resp, toResponse(u))
	}
	c.JSON(http.StatusOK, gin.H{"users": resp})
}

type createUserRequest struct {
	Username string `json:"username" binding:"required,min=3,max=50"`
	Password string `json:"password" binding:"required,min=12"`
	Role     string `json:"role" binding:"required,oneof=admin customer"`
}

func (h *Handler) Create(c *gin.Context) {
	var req createUserRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "validation error", "details": err.Error()})
		return
	}
	user, err := h.service.Create(c.Request.Context(), req.Username, req.Password, req.Role)
	if err != nil {
		if errors.Is(err, ErrAdminLimitReached) {
			c.JSON(http.StatusConflict, gin.H{"error": "admin limit reached"})
		}
		if errors.Is(err, ErrUsernameTaken) {
			c.JSON(http.StatusConflict, gin.H{"error": "username already in use"})
			return
		}
		if errors.Is(err, ErrCustomerAccountsDisabled) {
			c.JSON(http.StatusForbidden, gin.H{"error": "customer accounts are disabled: enable customer login or registration first"})
			return
		}
		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to create user"})
		return
	}
	c.JSON(http.StatusCreated, toResponse(user))
}

func (h *Handler) Get(c *gin.Context) {
	id, err := uuid.Parse(c.Param("id"))
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid id"})
		return
	}
	user, err := h.service.FindByID(c.Request.Context(), id)
	if err != nil {
		if errors.Is(err, ErrNotFound) {
			c.JSON(http.StatusNotFound, gin.H{"error": "user not found"})
			return
		}
		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to get user"})
		return
	}
	c.JSON(http.StatusOK, toResponse(user))
}

func (h *Handler) GetRole(c *gin.Context) {
	role := c.Param("role")

	if role == "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid role"})
		return
	}

	count, err := h.service.CountByRole(c.Request.Context(), role)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{
			"error": "failed to count users",
		})
		return
	}

	c.JSON(http.StatusOK, count)
}

type updateUserRequest struct {
	Username string `json:"username" binding:"required,min=3,max=50"`
	IsActive bool   `json:"is_active"`
}

func (h *Handler) Update(c *gin.Context) {
	id, err := uuid.Parse(c.Param("id"))
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid id"})
		return
	}
	var req updateUserRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "validation error", "details": err.Error()})
		return
	}

	user, err := h.service.UpdateProfile(c.Request.Context(), id, req.Username, req.IsActive)
	if err != nil {
		if errors.Is(err, ErrNotFound) {
			c.JSON(http.StatusNotFound, gin.H{"error": "user not found"})
			return
		}
		if errors.Is(err, ErrUsernameTaken) {
			c.JSON(http.StatusConflict, gin.H{"error": "username already in use"})
			return
		}
		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to update user"})
		return
	}
	c.JSON(http.StatusOK, toResponse(user))
}

func (h *Handler) Delete(c *gin.Context) {
	id, err := uuid.Parse(c.Param("id"))
	if err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid id"})
		return
	}
	if err := h.service.Delete(c.Request.Context(), id); err != nil {
		if errors.Is(err, ErrNotFound) {
			c.JSON(http.StatusNotFound, gin.H{"error": "user not found"})
			return
		}
		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to delete user"})
		return
	}
	c.Status(http.StatusNoContent)
}