package handler

import (
	"bugulma/backend/internal/service"
	"fmt"
	"net/http"

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

// I18nHandler handles i18n API requests
type I18nHandler struct {
	i18nService *service.I18nService
}

// NewI18nHandler creates a new i18n handler
func NewI18nHandler(i18nService *service.I18nService) *I18nHandler {
	return &I18nHandler{
		i18nService: i18nService,
	}
}

// GetUITranslations returns UI translations for a locale
// @Summary Get UI translations
// @Tags i18n
// @Produce json
// @Param locale path string true "Locale code (en, tt)"
// @Success 200 {object} map[string]string
// @Router /api/i18n/ui/{locale} [get]
func (h *I18nHandler) GetUITranslations(c *gin.Context) {
	locale := c.Param("locale")
	if !h.i18nService.ValidateLocale(locale) {
		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid locale"})
		return
	}

	ctx := c.Request.Context()

	// Get all UI translations for this locale from the database
	// UI translations are stored with entityType="ui", entityID="ui"
	localizations, err := h.i18nService.GetUITranslationsForLocale(ctx, locale)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": fmt.Sprintf("Failed to load UI translations: %v", err)})
		return
	}

	c.JSON(http.StatusOK, gin.H{
		"locale":       locale,
		"translations": localizations,
	})
}

// GetDataTranslation returns a data translation
// @Summary Get data translation
// @Tags i18n
// @Produce json
// @Param entityType path string true "Entity type"
// @Param entityID path string true "Entity ID"
// @Param field path string true "Field name"
// @Param locale query string true "Locale code"
// @Success 200 {object} map[string]string
// @Router /api/i18n/data/{entityType}/{entityID}/{field} [get]
func (h *I18nHandler) GetDataTranslation(c *gin.Context) {
	entityType := c.Param("entityType")
	entityID := c.Param("entityID")
	field := c.Param("field")
	locale := c.Query("locale")

	if locale == "" {
		locale = service.DefaultLocale
	}

	if !h.i18nService.ValidateLocale(locale) {
		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid locale"})
		return
	}

	// GetDataTranslation returns only a string (no error), so we need to handle it differently
	// For now, we'll need the source text as fallback - this should come from the entity
	// In a real scenario, you'd fetch the entity first to get the source text
	translated := h.i18nService.GetDataTranslation(
		c.Request.Context(),
		entityType,
		entityID,
		field,
		locale,
		"", // Fallback would need to be provided from entity source
	)

	c.JSON(http.StatusOK, gin.H{
		"entity_type": entityType,
		"entity_id":   entityID,
		"field":       field,
		"locale":      locale,
		"value":       translated,
	})
}

// GetSupportedLocales returns all supported locales
// @Summary Get supported locales
// @Tags i18n
// @Produce json
// @Success 200 {object} map[string]interface{}
// @Router /api/i18n/locales [get]
func (h *I18nHandler) GetSupportedLocales(c *gin.Context) {
	locales, err := h.i18nService.GetSupportedLocales(c.Request.Context())
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	c.JSON(http.StatusOK, gin.H{
		"locales":        locales,
		"default_locale": service.DefaultLocale,
		"supported":      service.SupportedLocales,
	})
}

// GetTranslationStats returns translation statistics
// @Summary Get translation statistics
// @Tags i18n
// @Produce json
// @Param entityType query string false "Entity type filter"
// @Success 200 {object} map[string]interface{}
// @Router /api/i18n/stats [get]
func (h *I18nHandler) GetTranslationStats(c *gin.Context) {
	entityType := c.Query("entityType")
	stats, err := h.i18nService.GetTranslationStats(c.Request.Context(), entityType)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	c.JSON(http.StatusOK, stats)
}

// Admin endpoints for i18n management

// UpdateUITranslation updates a UI translation (admin only)
// @Summary Update UI translation
// @Tags admin
// @Accept json
// @Produce json
// @Param locale path string true "Locale code"
// @Param key path string true "Translation key"
// @Param request body UpdateUITranslationRequest true "Translation value"
// @Success 200 {object} map[string]string
// @Router /api/v1/admin/i18n/ui/:locale/:key [put]
func (h *I18nHandler) UpdateUITranslation(c *gin.Context) {
	locale := c.Param("locale")
	key := c.Param("key")

	if !h.i18nService.ValidateLocale(locale) {
		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid locale"})
		return
	}

	var req UpdateUITranslationRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}

	if err := h.i18nService.SetUITranslation(c.Request.Context(), key, locale, req.Value); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	c.JSON(http.StatusOK, gin.H{"message": "Translation updated"})
}

type UpdateUITranslationRequest struct {
	Value string `json:"value" binding:"required"`
}

// BulkUpdateUITranslations updates multiple UI translations (admin only)
// @Summary Bulk update UI translations
// @Tags admin
// @Accept json
// @Produce json
// @Param request body BulkUpdateUITranslationsRequest true "Bulk update request"
// @Success 200 {object} map[string]string
// @Router /api/v1/admin/i18n/ui/bulk-update [post]
func (h *I18nHandler) BulkUpdateUITranslations(c *gin.Context) {
	var req BulkUpdateUITranslationsRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}

	updates := make(map[string]map[string]string) // locale -> key -> value
	for _, update := range req.Updates {
		if updates[update.Locale] == nil {
			updates[update.Locale] = make(map[string]string)
		}
		updates[update.Locale][update.Key] = update.Value
	}

	for locale, keys := range updates {
		if !h.i18nService.ValidateLocale(locale) {
			c.JSON(http.StatusBadRequest, gin.H{"error": fmt.Sprintf("Invalid locale: %s", locale)})
			return
		}

		for key, value := range keys {
			if err := h.i18nService.SetUITranslation(c.Request.Context(), key, locale, value); err != nil {
				c.JSON(http.StatusInternalServerError, gin.H{"error": fmt.Sprintf("Failed to update %s:%s: %v", locale, key, err)})
				return
			}
		}
	}

	c.JSON(http.StatusOK, gin.H{"message": "Translations updated"})
}

type BulkUpdateUITranslationsRequest struct {
	Updates []TranslationUpdate `json:"updates" binding:"required"`
}

type TranslationUpdate struct {
	Locale string `json:"locale" binding:"required"`
	Key    string `json:"key" binding:"required"`
	Value  string `json:"value" binding:"required"`
}

// AutoTranslateMissing auto-translates missing UI keys (admin only)
// @Summary Auto-translate missing keys
// @Tags admin
// @Accept json
// @Produce json
// @Param request body AutoTranslateRequest true "Auto-translate request"
// @Success 200 {object} map[string]interface{}
// @Router /api/v1/admin/i18n/ui/auto-translate [post]
func (h *I18nHandler) AutoTranslateMissing(c *gin.Context) {
	var req AutoTranslateRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}

	if !h.i18nService.ValidateLocale(req.TargetLocale) {
		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid target locale"})
		return
	}

	// Get all UI keys for source locale
	sourceTranslations, err := h.i18nService.GetUITranslationsForLocale(c.Request.Context(), req.SourceLocale)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	// Get existing target translations
	targetTranslations, err := h.i18nService.GetUITranslationsForLocale(c.Request.Context(), req.TargetLocale)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	// Find missing keys
	var keysToTranslate []string
	for key := range sourceTranslations {
		if _, exists := targetTranslations[key]; !exists {
			keysToTranslate = append(keysToTranslate, key)
		}
	}

	if len(keysToTranslate) == 0 {
		c.JSON(http.StatusOK, gin.H{"message": "No missing translations", "translated": 0})
		return
	}

	// Batch translate
	translated, err := h.i18nService.BatchTranslateUI(c.Request.Context(), keysToTranslate, req.SourceLocale, req.TargetLocale)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	c.JSON(http.StatusOK, gin.H{
		"message":    "Translations completed",
		"translated": len(translated),
		"results":    translated,
	})
}

type AutoTranslateRequest struct {
	SourceLocale string `json:"sourceLocale" binding:"required"`
	TargetLocale string `json:"targetLocale" binding:"required"`
}

// GetTranslationKeys returns all translation keys with status (admin only)
// @Summary Get translation keys with status
// @Tags admin
// @Produce json
// @Param locale path string true "Locale code"
// @Success 200 {object} map[string]interface{}
// @Router /api/v1/admin/i18n/ui/:locale/keys [get]
func (h *I18nHandler) GetTranslationKeys(c *gin.Context) {
	locale := c.Param("locale")

	if !h.i18nService.ValidateLocale(locale) {
		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid locale"})
		return
	}

	// Get source locale (default: ru)
	sourceLocale := service.DefaultLocale
	sourceTranslations, err := h.i18nService.GetUITranslationsForLocale(c.Request.Context(), sourceLocale)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	// Get target locale translations
	targetTranslations, err := h.i18nService.GetUITranslationsForLocale(c.Request.Context(), locale)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	// Build keys with status
	keys := make([]map[string]interface{}, 0)
	for key, sourceValue := range sourceTranslations {
		status := "missing"
		value := ""
		if targetValue, exists := targetTranslations[key]; exists {
			status = "translated"
			value = targetValue
		}

		keys = append(keys, map[string]interface{}{
			"key":    key,
			"source": sourceValue,
			"value":  value,
			"status": status,
		})
	}

	c.JSON(http.StatusOK, gin.H{
		"locale":     locale,
		"keys":       keys,
		"total":      len(keys),
		"translated": len(targetTranslations),
		"missing":    len(sourceTranslations) - len(targetTranslations),
	})
}

// UpdateDataTranslation updates a data translation (admin only)
// @Summary Update data translation
// @Tags admin
// @Accept json
// @Produce json
// @Param entityType path string true "Entity type"
// @Param entityID path string true "Entity ID"
// @Param field path string true "Field name"
// @Param locale path string true "Locale code"
// @Param request body UpdateDataTranslationRequest true "Translation value"
// @Success 200 {object} map[string]string
// @Router /api/v1/admin/i18n/data/:entityType/:entityID/:field/:locale [put]
func (h *I18nHandler) UpdateDataTranslation(c *gin.Context) {
	entityType := c.Param("entityType")
	entityID := c.Param("entityID")
	field := c.Param("field")
	locale := c.Param("locale")

	if !h.i18nService.ValidateLocale(locale) {
		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid locale"})
		return
	}

	var req UpdateDataTranslationRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}

	if err := h.i18nService.SetDataTranslation(c.Request.Context(), entityType, entityID, field, locale, req.Value); err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
		return
	}

	c.JSON(http.StatusOK, gin.H{"message": "Translation updated"})
}

type UpdateDataTranslationRequest struct {
	Value string `json:"value" binding:"required"`
}

// BulkTranslateData bulk translates entities (admin only)
// @Summary Bulk translate data
// @Tags admin
// @Accept json
// @Produce json
// @Param request body BulkTranslateDataRequest true "Bulk translate request"
// @Success 200 {object} map[string]interface{}
// @Router /api/v1/admin/i18n/data/bulk-translate [post]
func (h *I18nHandler) BulkTranslateData(c *gin.Context) {
	var req BulkTranslateDataRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
		return
	}

	if !h.i18nService.ValidateLocale(req.TargetLocale) {
		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid target locale"})
		return
	}

	// TODO: Implement bulk data translation
	c.JSON(http.StatusNotImplemented, gin.H{"error": "Bulk data translation not yet implemented"})
}

type BulkTranslateDataRequest struct {
	EntityType   string   `json:"entityType" binding:"required"`
	EntityIDs    []string `json:"entityIDs" binding:"required"`
	TargetLocale string   `json:"targetLocale" binding:"required"`
	Fields       []string `json:"fields"`
}

// GetMissingTranslations returns entities with missing translations (admin only)
// @Summary Get entities with missing translations
// @Tags admin
// @Produce json
// @Param entityType path string true "Entity type"
// @Param locale query string true "Locale code"
// @Success 200 {object} map[string]interface{}
// @Router /api/v1/admin/i18n/data/:entityType/missing [get]
func (h *I18nHandler) GetMissingTranslations(c *gin.Context) {
	_ = c.Param("entityType") // Entity type - for future use
	locale := c.Query("locale")

	if locale == "" {
		locale = service.DefaultLocale
	}

	if !h.i18nService.ValidateLocale(locale) {
		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid locale"})
		return
	}

	// TODO: Implement missing translations detection
	c.JSON(http.StatusNotImplemented, gin.H{"error": "Missing translations detection not yet implemented"})
}