package handler

import (
	"baron-sso-backend/internal/domain"
	"errors"
	"strings"
	"time"

	"github.com/gofiber/fiber/v2"
	"golang.org/x/crypto/bcrypt"
	"gorm.io/gorm"
)

type UserHandler struct {
	DB *gorm.DB
}

func NewUserHandler(db *gorm.DB) *UserHandler {
	return &UserHandler{DB: db}
}

type userSummary struct {
	ID              string `json:"id"`
	Email           string `json:"email"`
	Name            string `json:"name"`
	Phone           string `json:"phone"`
	Role            string `json:"role"`
	Status          string `json:"status"`
	CompanyCode     string `json:"companyCode"`
	Department      string `json:"department"`
	CreatedAt       string `json:"createdAt"`
	UpdatedAt       string `json:"updatedAt"`
}

type userListResponse struct {
	Items  []userSummary `json:"items"`
	Limit  int           `json:"limit"`
	Offset int           `json:"offset"`
	Total  int64         `json:"total"`
}

func (h *UserHandler) ListUsers(c *fiber.Ctx) error {
	if h.DB == nil {
		return c.Status(fiber.StatusServiceUnavailable).JSON(fiber.Map{"error": "database not available"})
	}

	limit := c.QueryInt("limit", 50)
	offset := c.QueryInt("offset", 0)
	search := strings.TrimSpace(c.Query("search"))

	if limit <= 0 {
		limit = 50
	}
	if offset < 0 {
		offset = 0
	}

	query := h.DB.Model(&domain.User{})
	if search != "" {
		like := "%" + search + "%"
		query = query.Where("email ILIKE ? OR name ILIKE ?", like, like)
	}

	var total int64
	if err := query.Count(&total).Error; err != nil {
		return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"error": err.Error()})
	}

	var users []domain.User
	if err := query.Order("created_at desc").Limit(limit).Offset(offset).Find(&users).Error; err != nil {
		return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"error": err.Error()})
	}

	items := make([]userSummary, 0, len(users))
	for _, u := range users {
		items = append(items, mapUserSummary(u))
	}

	return c.JSON(userListResponse{Items: items, Limit: limit, Offset: offset, Total: total})
}

func (h *UserHandler) GetUser(c *fiber.Ctx) error {
	if h.DB == nil {
		return c.Status(fiber.StatusServiceUnavailable).JSON(fiber.Map{"error": "database not available"})
	}

	userID := strings.TrimSpace(c.Params("id"))
	if userID == "" {
		return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{"error": "user id is required"})
	}

	var user domain.User
	if err := h.DB.First(&user, "id = ?", userID).Error; err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return c.Status(fiber.StatusNotFound).JSON(fiber.Map{"error": "user not found"})
		}
		return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"error": err.Error()})
	}

	return c.JSON(mapUserSummary(user))
}

func (h *UserHandler) CreateUser(c *fiber.Ctx) error {
	if h.DB == nil {
		return c.Status(fiber.StatusServiceUnavailable).JSON(fiber.Map{"error": "database not available"})
	}

	var req struct {
		Email       string `json:"email"`
		Password    string `json:"password"`
		Name        string `json:"name"`
		Phone       string `json:"phone"`
		Role        string `json:"role"`
		CompanyCode string `json:"companyCode"`
		Department  string `json:"department"`
	}
	if err := c.BodyParser(&req); err != nil {
		return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{"error": "invalid request body"})
	}

	email := strings.TrimSpace(req.Email)
	if email == "" {
		return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{"error": "email is required"})
	}
	password := req.Password
	if password == "" {
		return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{"error": "password is required"})
	}
	name := strings.TrimSpace(req.Name)
	if name == "" {
		return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{"error": "name is required"})
	}

	// Check duplicates
	var exists domain.User
	if err := h.DB.Where("email = ?", email).First(&exists).Error; err == nil {
		return c.Status(fiber.StatusConflict).JSON(fiber.Map{"error": "email already exists"})
	}

	hashedPassword, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
	if err != nil {
		return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"error": "failed to hash password"})
	}

	user := domain.User{
		Email:           email,
		PasswordHash:    string(hashedPassword),
		Name:            name,
		Phone:           req.Phone,
		Role:            req.Role, // default "user" handled by GORM if empty, but struct default usually works on zero value? GORM default tag works for zero value.
		CompanyCode:     req.CompanyCode,
		Department:      req.Department,
		Status:          "active",
		AffiliationType: "internal", // Defaulting for now
	}

	if user.Role == "" {
		user.Role = "user"
	}

	if err := h.DB.Create(&user).Error; err != nil {
		return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"error": err.Error()})
	}

	return c.Status(fiber.StatusCreated).JSON(mapUserSummary(user))
}

func (h *UserHandler) UpdateUser(c *fiber.Ctx) error {
	if h.DB == nil {
		return c.Status(fiber.StatusServiceUnavailable).JSON(fiber.Map{"error": "database not available"})
	}

	userID := strings.TrimSpace(c.Params("id"))
	if userID == "" {
		return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{"error": "user id is required"})
	}

	var user domain.User
	if err := h.DB.First(&user, "id = ?", userID).Error; err != nil {
		if errors.Is(err, gorm.ErrRecordNotFound) {
			return c.Status(fiber.StatusNotFound).JSON(fiber.Map{"error": "user not found"})
		}
		return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"error": err.Error()})
	}

	var req struct {
		Password    *string `json:"password"`
		Name        *string `json:"name"`
		Phone       *string `json:"phone"`
		Role        *string `json:"role"`
		Status      *string `json:"status"`
		CompanyCode *string `json:"companyCode"`
		Department  *string `json:"department"`
	}
	if err := c.BodyParser(&req); err != nil {
		return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{"error": "invalid request body"})
	}

	if req.Name != nil {
		user.Name = strings.TrimSpace(*req.Name)
	}
	if req.Phone != nil {
		user.Phone = strings.TrimSpace(*req.Phone)
	}
	if req.Role != nil {
		user.Role = strings.TrimSpace(*req.Role)
	}
	if req.Status != nil {
		status := strings.ToLower(strings.TrimSpace(*req.Status))
		if status == "active" || status == "inactive" || status == "blocked" {
			user.Status = status
		}
	}
	if req.CompanyCode != nil {
		user.CompanyCode = strings.TrimSpace(*req.CompanyCode)
	}
	if req.Department != nil {
		user.Department = strings.TrimSpace(*req.Department)
	}

	if req.Password != nil && *req.Password != "" {
		hashedPassword, err := bcrypt.GenerateFromPassword([]byte(*req.Password), bcrypt.DefaultCost)
		if err != nil {
			return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"error": "failed to hash password"})
		}
		user.PasswordHash = string(hashedPassword)
	}

	if err := h.DB.Save(&user).Error; err != nil {
		return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"error": err.Error()})
	}

	return c.JSON(mapUserSummary(user))
}

func (h *UserHandler) DeleteUser(c *fiber.Ctx) error {
	if h.DB == nil {
		return c.Status(fiber.StatusServiceUnavailable).JSON(fiber.Map{"error": "database not available"})
	}

	userID := strings.TrimSpace(c.Params("id"))
	if userID == "" {
		return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{"error": "user id is required"})
	}

	// Soft delete
	if err := h.DB.Delete(&domain.User{}, "id = ?", userID).Error; err != nil {
		return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"error": err.Error()})
	}

	return c.SendStatus(fiber.StatusNoContent)
}

func mapUserSummary(u domain.User) userSummary {
	return userSummary{
		ID:          u.ID,
		Email:       u.Email,
		Name:        u.Name,
		Phone:       u.Phone,
		Role:        u.Role,
		Status:      u.Status,
		CompanyCode: u.CompanyCode,
		Department:  u.Department,
		CreatedAt:   u.CreatedAt.Format(time.RFC3339),
		UpdatedAt:   u.UpdatedAt.Format(time.RFC3339),
	}
}