package v1

import (
	"net/http"
	"strconv"

	"github.com/gin-gonic/gin"

	"github.com/gochat/gochat/internal/service"
	"github.com/gochat/gochat/pkg/response"
)

// AssignableAgentHandler handles endpoints for finding agents assignable to conversations.
// Reference: Chatwoot app/controllers/api/v1/accounts/assignable_agents_controller.rb
// Two routes:
//  1. GET /api/v1/accounts/:account_id/assignable_agents (with inbox_ids[] query param)
//  2. GET /api/v1/accounts/:account_id/inboxes/:inbox_id/assignable_agents (single inbox)
type AssignableAgentHandler struct {
	svc *service.AssignableAgentService
}

// NewAssignableAgentHandler creates a new AssignableAgentHandler.
func NewAssignableAgentHandler(svc *service.AssignableAgentService) *AssignableAgentHandler {
	return &AssignableAgentHandler{svc: svc}
}

// List returns agents that can be assigned to conversations in the specified inbox(es).
// Supports two modes:
//  1. Standalone resource: GET /api/v1/accounts/:account_id/assignable_agents?inbox_ids[]=1&inbox_ids[]=2
//     (Ref: Chatwoot resources :assignable_agents, only: [:index] — takes inbox_ids[] query param)
//  2. Inbox member action: GET /api/v1/accounts/:account_id/inboxes/:inbox_id/assignable_agents
//     (Ref: Chatwoot get :assignable_agents, on: :member on inboxes)
//
// 返回带workload信息的agent列表，按workload升序排序(最少conversations优先)。
func (h *AssignableAgentHandler) List(c *gin.Context) {
	if h.svc == nil {
		response.AbortWithStatusError(c, http.StatusUnprocessableEntity, response.ErrInternal, "assignable agent service unavailable")
		return
	}

	accountID := getAccountID(c)
	if accountID == 0 {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid account_id")
		return
	}

	// Determine inbox IDs from either path param or query param
	inboxIDs := []uint{}

	// Mode 2: inbox_id from URL path (GET /accounts/:account_id/inboxes/:inbox_id/assignable_agents)
	if inboxIDStr := c.Param("inbox_id"); inboxIDStr != "" {
		inboxID, parseErr := strconv.ParseUint(inboxIDStr, 10, 32)
		if parseErr != nil {
			response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid inbox_id")
			return
		}
		inboxIDs = append(inboxIDs, uint(inboxID))
	}

	// Mode 1 & 2: additional inbox IDs from query param inbox_ids[]
	if queryInboxIDs, exists := c.GetQueryArray("inbox_ids[]"); exists {
		for _, qid := range queryInboxIDs {
			id, parseErr := strconv.ParseUint(qid, 10, 32)
			if parseErr == nil {
				// Avoid duplicate if path inbox_id matches query inbox_id
				isDup := false
				if len(inboxIDs) > 0 && uint(id) == inboxIDs[0] {
					isDup = true
				}
				if !isDup {
					inboxIDs = append(inboxIDs, uint(id))
				}
			}
		}
	}

	agents, svcErr := h.svc.GetAssignableAgents(c.Request.Context(), accountID, inboxIDs)
	if svcErr != nil {
		response.AbortWithStatusError(c, http.StatusUnprocessableEntity, response.ErrInternal, "failed to list assignable agents")
		return
	}

	response.OK(c, agents)
}