package v1

import (
	"net/http"
	"strconv"
	"strings"

	"github.com/gin-gonic/gin"
	"github.com/gochat/gochat/internal/service"
	applogger "github.com/gochat/gochat/pkg/logger"
	"github.com/gochat/gochat/pkg/response"
)

// CaptainTaskExtendedHandler handles label_suggestion and follow_up GET endpoints.
// Reference: Chatwoot Captain::ConversationInsightController (label_suggestion + follow_up)
type CaptainTaskExtendedHandler struct {
	svc *service.CaptainTaskExtendedService
}

func NewCaptainTaskExtendedHandler(svc *service.CaptainTaskExtendedService) *CaptainTaskExtendedHandler {
	return &CaptainTaskExtendedHandler{svc: svc}
}

// LabelSuggestion returns AI-generated label suggestions for conversations.
// GET /api/v1/accounts/:id/captain/tasks/label_suggestion
func (h *CaptainTaskExtendedHandler) LabelSuggestion(c *gin.Context) {
	accountID, err := strconv.ParseUint(c.Param("id"), 10, 64)
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid account_id")
		return
	}

	if c.Request.Method == http.MethodPost {
		var req service.ChatwootLabelSuggestionRequest
		if err := c.ShouldBindJSON(&req); err != nil {
			response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid request body: "+err.Error())
			return
		}
		result, err := h.svc.LabelSuggestion(c.Request.Context(), uint(accountID), &req)
		if err != nil {
			applogger.L().Errorf("Label suggestion: %v", err)
			renderCaptainTaskError(c, err)
			return
		}
		renderCaptainExtendedTaskResult(c, result)
		return
	}

	// Parse conversation_ids from query param (comma-separated)
	convIDsStr := c.Query("conversation_ids")
	if convIDsStr == "" {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrValidation, "conversation_ids required")
		return
	}

	convIDs, err := parseUintSlice(convIDsStr)
	if err != nil || len(convIDs) == 0 {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrValidation, "invalid conversation_ids format")
		return
	}

	assistantID, _ := strconv.ParseUint(c.Query("assistant_id"), 10, 64)

	query := &service.LabelSuggestionQuery{
		ConversationIDs: convIDs,
		AssistantID:     uint(assistantID),
	}

	result, err := h.svc.SuggestLabels(c.Request.Context(), uint(accountID), query)
	if err != nil {
		applogger.L().Errorf("Label suggestion: %v", err)
		response.AbortWithStatusError(c, http.StatusInternalServerError, response.ErrInternal, "failed to generate label suggestions")
		return
	}

	response.OK(c, result)
}

// FollowUp returns AI-generated follow-up task suggestions for conversations.
// GET /api/v1/accounts/:id/captain/tasks/follow_up
func (h *CaptainTaskExtendedHandler) FollowUp(c *gin.Context) {
	accountID, err := strconv.ParseUint(c.Param("id"), 10, 64)
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid account_id")
		return
	}

	if c.Request.Method == http.MethodPost {
		var req service.ChatwootFollowUpRequest
		if err := c.ShouldBindJSON(&req); err != nil {
			response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid request body: "+err.Error())
			return
		}
		result, err := h.svc.FollowUp(c.Request.Context(), uint(accountID), &req)
		if err != nil {
			applogger.L().Errorf("Follow-up: %v", err)
			renderCaptainTaskError(c, err)
			return
		}
		renderCaptainExtendedTaskResult(c, result)
		return
	}

	convIDsStr := c.Query("conversation_ids")
	if convIDsStr == "" {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrValidation, "conversation_ids required")
		return
	}

	convIDs, err := parseUintSlice(convIDsStr)
	if err != nil || len(convIDs) == 0 {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrValidation, "invalid conversation_ids format")
		return
	}

	assistantID, _ := strconv.ParseUint(c.Query("assistant_id"), 10, 64)

	query := &service.FollowUpQuery{
		ConversationIDs: convIDs,
		AssistantID:     uint(assistantID),
	}

	result, err := h.svc.SuggestFollowUp(c.Request.Context(), uint(accountID), query)
	if err != nil {
		applogger.L().Errorf("Follow-up suggestion: %v", err)
		response.AbortWithStatusError(c, http.StatusInternalServerError, response.ErrInternal, "failed to generate follow-up suggestions")
		return
	}

	response.OK(c, result)
}

func renderCaptainExtendedTaskResult(c *gin.Context, result *service.ChatwootTaskResult) {
	if result == nil || result.Message == nil {
		c.JSON(http.StatusOK, gin.H{"message": nil})
		return
	}
	payload := gin.H{"message": *result.Message}
	if result.FollowUpContext != nil {
		payload["follow_up_context"] = result.FollowUpContext
	}
	c.JSON(http.StatusOK, payload)
}

// parseUintSlice parses a comma-separated string of uint values.
func parseUintSlice(s string) ([]uint, error) {
	parts := strings.Split(s, ",")
	var result []uint
	for _, p := range parts {
		p = strings.TrimSpace(p)
		if p == "" {
			continue
		}
		v, err := strconv.ParseUint(p, 10, 64)
		if err != nil {
			return nil, err
		}
		result = append(result, uint(v))
	}
	return result, nil
}