package handler

import (
	"strconv"

	"accounting-app/pkg/api"
	"accounting-app/internal/service"

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

// TemplateHandler handles HTTP requests for transaction templates
type TemplateHandler struct {
	templateService *service.TemplateService
}

// NewTemplateHandler creates a new TemplateHandler instance
func NewTemplateHandler(templateService *service.TemplateService) *TemplateHandler {
	return &TemplateHandler{
		templateService: templateService,
	}
}

// RegisterRoutes registers template routes
func (h *TemplateHandler) RegisterRoutes(router *gin.RouterGroup) {
	templates := router.Group("/templates")
	{
		templates.POST("", h.CreateTemplate)
		templates.GET("", h.GetAllTemplates)
		templates.GET("/:id", h.GetTemplate)
		templates.PUT("/:id", h.UpdateTemplate)
		templates.DELETE("/:id", h.DeleteTemplate)
		templates.PUT("/sort", h.UpdateSortOrder)
	}
}

// CreateTemplate creates a new transaction template
// @Summary Create a new transaction template
// @Tags templates
// @Accept json
// @Produce json
// @Param template body service.TemplateInput true "Template data"
// @Success 201 {object} api.Response{data=models.TransactionTemplate}
// @Failure 400 {object} api.Response
// @Router /templates [post]
func (h *TemplateHandler) CreateTemplate(c *gin.Context) {
	userId, exists := c.Get("user_id")
	if !exists {
		api.Unauthorized(c, "User not authenticated")
		return
	}

	var input service.TemplateInput
	if err := c.ShouldBindJSON(&input); err != nil {
		api.BadRequest(c, "Invalid request body: "+err.Error())
		return
	}

	template, err := h.templateService.CreateTemplate(userId.(uint), input)
	if err != nil {
		api.BadRequest(c, err.Error())
		return
	}

	api.Created(c, template)
}

// GetAllTemplates retrieves all templates for the current user
// @Summary Get all transaction templates
// @Tags templates
// @Produce json
// @Success 200 {object} api.Response{data=[]models.TransactionTemplate}
// @Router /templates [get]
func (h *TemplateHandler) GetAllTemplates(c *gin.Context) {
	userId, exists := c.Get("user_id")
	if !exists {
		api.Unauthorized(c, "User not authenticated")
		return
	}

	templates, err := h.templateService.GetAllTemplates(userId.(uint))
	if err != nil {
		api.InternalError(c, err.Error())
		return
	}

	api.Success(c, templates)
}

// GetTemplate retrieves a template by ID
// @Summary Get a transaction template by ID
// @Tags templates
// @Produce json
// @Param id path int true "Template ID"
// @Success 200 {object} api.Response{data=models.TransactionTemplate}
// @Failure 404 {object} api.Response
// @Router /templates/{id} [get]
func (h *TemplateHandler) GetTemplate(c *gin.Context) {
	userId, exists := c.Get("user_id")
	if !exists {
		api.Unauthorized(c, "User not authenticated")
		return
	}

	id, err := strconv.ParseUint(c.Param("id"), 10, 32)
	if err != nil {
		api.BadRequest(c, "Invalid template ID")
		return
	}

	template, err := h.templateService.GetTemplate(userId.(uint), uint(id))
	if err != nil {
		if err == service.ErrTemplateNotFound {
			api.NotFound(c, "Template not found")
			return
		}
		api.InternalError(c, err.Error())
		return
	}

	api.Success(c, template)
}

// UpdateTemplate updates an existing template
// @Summary Update a transaction template
// @Tags templates
// @Accept json
// @Produce json
// @Param id path int true "Template ID"
// @Param template body service.TemplateInput true "Template data"
// @Success 200 {object} api.Response{data=models.TransactionTemplate}
// @Failure 400 {object} api.Response
// @Failure 404 {object} api.Response
// @Router /templates/{id} [put]
func (h *TemplateHandler) UpdateTemplate(c *gin.Context) {
	userId, exists := c.Get("user_id")
	if !exists {
		api.Unauthorized(c, "User not authenticated")
		return
	}

	id, err := strconv.ParseUint(c.Param("id"), 10, 32)
	if err != nil {
		api.BadRequest(c, "Invalid template ID")
		return
	}

	var input service.TemplateInput
	if err := c.ShouldBindJSON(&input); err != nil {
		api.BadRequest(c, "Invalid request body: "+err.Error())
		return
	}

	template, err := h.templateService.UpdateTemplate(userId.(uint), uint(id), input)
	if err != nil {
		if err == service.ErrTemplateNotFound {
			api.NotFound(c, "Template not found")
			return
		}
		api.BadRequest(c, err.Error())
		return
	}

	api.Success(c, template)
}

// DeleteTemplate deletes a template
// @Summary Delete a transaction template
// @Tags templates
// @Produce json
// @Param id path int true "Template ID"
// @Success 200 {object} api.Response
// @Failure 404 {object} api.Response
// @Router /templates/{id} [delete]
func (h *TemplateHandler) DeleteTemplate(c *gin.Context) {
	userId, exists := c.Get("user_id")
	if !exists {
		api.Unauthorized(c, "User not authenticated")
		return
	}

	id, err := strconv.ParseUint(c.Param("id"), 10, 32)
	if err != nil {
		api.BadRequest(c, "Invalid template ID")
		return
	}

	err = h.templateService.DeleteTemplate(userId.(uint), uint(id))
	if err != nil {
		if err == service.ErrTemplateNotFound {
			api.NotFound(c, "Template not found")
			return
		}
		api.InternalError(c, err.Error())
		return
	}

	api.Success(c, gin.H{"message": "Template deleted successfully"})
}

// UpdateSortOrderInput represents the input for updating sort order
type UpdateSortOrderInput struct {
	IDs []uint `json:"ids" binding:"required"`
}

// UpdateSortOrder updates the sort order of templates
// @Summary Update template sort order
// @Tags templates
// @Accept json
// @Produce json
// @Param input body UpdateSortOrderInput true "Template IDs in desired order"
// @Success 200 {object} api.Response
// @Failure 400 {object} api.Response
// @Router /templates/sort [put]
func (h *TemplateHandler) UpdateSortOrder(c *gin.Context) {
	userId, exists := c.Get("user_id")
	if !exists {
		api.Unauthorized(c, "User not authenticated")
		return
	}

	var input UpdateSortOrderInput
	if err := c.ShouldBindJSON(&input); err != nil {
		api.BadRequest(c, "Invalid request body: "+err.Error())
		return
	}

	if len(input.IDs) == 0 {
		api.BadRequest(c, "IDs array cannot be empty")
		return
	}

	err := h.templateService.UpdateSortOrder(userId.(uint), input.IDs)
	if err != nil {
		api.InternalError(c, err.Error())
		return
	}

	api.Success(c, gin.H{"message": "Sort order updated successfully"})
}