package v1

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

	"github.com/gin-gonic/gin"
	"github.com/gochat/gochat/internal/campaign"

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

// CampaignHandler handles Campaign CRUD + trigger actions.
// Reference: Chatwoot app/controllers/api/v1/campaigns_controller.rb
type CampaignHandler struct {
	svc *service.CampaignService
}

// NewCampaignHandler creates a new Campaign handler.
func NewCampaignHandler(svc *service.CampaignService) *CampaignHandler {
	return &CampaignHandler{svc: svc}
}

// List returns all campaigns for an account.
// GET /api/v1/accounts/:id/campaigns
func (h *CampaignHandler) List(c *gin.Context) {
	accountID := getAccountID(c)
	if accountID == 0 {
		response.AbortWithStatusError(c, http.StatusUnauthorized, response.ErrUnauthorized, "account not identified")
		return
	}

	campaigns, _, err := h.svc.List(c.Request.Context(), accountID, 0, 0)
	if err != nil {
		applogger.L().Errorf("List campaigns for account %d: %v", accountID, err)
		handleServiceError(c, err)
		return
	}

	c.JSON(http.StatusOK, serializeCampaigns(campaigns, accountID))
}

// Get returns a single campaign by ID.
// GET /api/v1/accounts/:id/campaigns/:campaign_id
func (h *CampaignHandler) Get(c *gin.Context) {
	accountID := getAccountID(c)
	if accountID == 0 {
		response.AbortWithStatusError(c, http.StatusUnauthorized, response.ErrUnauthorized, "account not identified")
		return
	}

	id, err := strconv.ParseUint(c.Param("campaign_id"), 10, 32)
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid campaign ID")
		return
	}

	campaign, svcErr := h.svc.Get(c.Request.Context(), uint(id), accountID)
	if svcErr != nil {
		applogger.L().Errorf("Get campaign %d for account %d: %v", id, accountID, svcErr)
		handleServiceError(c, svcErr)
		return
	}

	c.JSON(http.StatusOK, serializeCampaign(campaign, accountID))
}

// Create creates a new campaign within an account.
// POST /api/v1/accounts/:id/campaigns
func (h *CampaignHandler) Create(c *gin.Context) {
	accountID := getAccountID(c)
	if accountID == 0 {
		response.AbortWithStatusError(c, http.StatusUnauthorized, response.ErrUnauthorized, "account not identified")
		return
	}

	// Accept both wrapped {"campaign": {...}} (Chatwoot style) and flat {...} payloads.
	// The frontend sends flat payload, so we prefer that format.
	var req service.CreateCampaignRequest
	var wrapper struct {
		Campaign service.CreateCampaignRequest `json:"campaign"`
	}
	rawBody, err := c.GetRawData()
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "cannot read request body")
		return
	}
	// Try wrapped format first (Chatwoot style)
	if err := json.Unmarshal(rawBody, &wrapper); err == nil && wrapper.Campaign.Title != "" {
		req = wrapper.Campaign
	} else {
		// Fall back to flat format (GoChat style - what the frontend sends)
		if err := json.Unmarshal(rawBody, &req); err != nil {
			response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, err.Error())
			return
		}
	}

	campaign, svcErr := h.svc.Create(c.Request.Context(), accountID, req)
	if svcErr != nil {
		applogger.L().Errorf("Create campaign for account %d: %v", accountID, svcErr)
		handleServiceError(c, svcErr)
		return
	}

	c.JSON(http.StatusOK, serializeCampaign(campaign, accountID))
}

// Update updates an existing campaign.
// PUT /api/v1/accounts/:id/campaigns/:campaign_id
func (h *CampaignHandler) Update(c *gin.Context) {
	accountID := getAccountID(c)
	if accountID == 0 {
		response.AbortWithStatusError(c, http.StatusUnauthorized, response.ErrUnauthorized, "account not identified")
		return
	}

	id, err := strconv.ParseUint(c.Param("campaign_id"), 10, 32)
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid campaign ID")
		return
	}

	// Chatwoot: params.require(:campaign) → request body must be {"campaign": {...}}
	var wrapper struct {
		Campaign service.UpdateCampaignRequest `json:"campaign"`
	}
	if err := c.ShouldBindJSON(&wrapper); err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, err.Error())
		return
	}
	req := wrapper.Campaign

	campaign, svcErr := h.svc.Update(c.Request.Context(), uint(id), accountID, req)
	if svcErr != nil {
		applogger.L().Errorf("Update campaign %d for account %d: %v", id, accountID, svcErr)
		handleServiceError(c, svcErr)
		return
	}

	c.JSON(http.StatusOK, serializeCampaign(campaign, accountID))
}

// Delete soft-deletes a campaign.
// DELETE /api/v1/accounts/:id/campaigns/:campaign_id
func (h *CampaignHandler) Delete(c *gin.Context) {
	accountID := getAccountID(c)
	if accountID == 0 {
		response.AbortWithStatusError(c, http.StatusUnauthorized, response.ErrUnauthorized, "account not identified")
		return
	}

	id, err := strconv.ParseUint(c.Param("campaign_id"), 10, 32)
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid campaign ID")
		return
	}

	if svcErr := h.svc.Delete(c.Request.Context(), uint(id), accountID); svcErr != nil {
		applogger.L().Errorf("Delete campaign %d for account %d: %v", id, accountID, svcErr)
		handleServiceError(c, svcErr)
		return
	}

	c.Status(http.StatusOK)
}

// Start triggers a campaign execution.
// POST /api/v1/accounts/:id/campaigns/:campaign_id/start
func (h *CampaignHandler) Start(c *gin.Context) {
	accountID := getAccountID(c)
	if accountID == 0 {
		response.AbortWithStatusError(c, http.StatusUnauthorized, response.ErrUnauthorized, "account not identified")
		return
	}

	id, err := strconv.ParseUint(c.Param("campaign_id"), 10, 32)
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid campaign ID")
		return
	}

	if svcErr := h.svc.Start(c.Request.Context(), uint(id), accountID); svcErr != nil {
		applogger.L().Errorf("Start campaign %d for account %d: %v", id, accountID, svcErr)
		handleServiceError(c, svcErr)
		return
	}

	response.OK(c, gin.H{"message": "campaign triggered successfully"})
}

func serializeCampaigns(campaigns []campaign.Campaign, accountID uint) []map[string]any {
	payload := make([]map[string]any, 0, len(campaigns))
	for i := range campaigns {
		payload = append(payload, serializeCampaign(&campaigns[i], accountID))
	}
	return payload
}

func serializeCampaign(item *campaign.Campaign, accountID uint) map[string]any {
	if item == nil {
		return map[string]any{}
	}
	id := item.DisplayID
	if id == 0 {
		id = item.ID
	}
	payload := map[string]any{
		"id":                                 id,
		"title":                              item.Title,
		"description":                        item.Description,
		"account_id":                         item.AccountID,
		"inbox":                              nil,
		"sender":                             nil,
		"message":                            item.Message,
		"template_params":                    campaignJSONValue(item.TemplateParams),
		"campaign_status":                    item.CampaignStatus,
		"enabled":                            item.Enabled,
		"campaign_type":                      item.CampaignType,
		"trigger_rules":                      campaignJSONValue(item.TriggerRules),
		"trigger_only_during_business_hours": item.TriggerOnlyDuringBusinessHours,
		"created_at":                         item.CreatedAt,
		"updated_at":                         item.UpdatedAt,
	}
	if item.Inbox.ID != 0 {
		payload["inbox"] = serializeInbox(&item.Inbox, nil, false)
	}
	if item.Sender != nil && item.Sender.ID != 0 {
		payload["sender"] = serializeAgentUser(item.Sender, accountID, "", "", false, 0)
	}
	if item.CampaignType == campaign.CampaignTypeOneOff {
		if item.ScheduledAt != nil {
			payload["scheduled_at"] = item.ScheduledAt.Unix()
		} else {
			payload["scheduled_at"] = nil
		}
		payload["audience"] = campaignJSONValue(item.Audience)
	}
	return payload
}

func campaignJSONValue(raw string) any {
	trimmed := strings.TrimSpace(raw)
	if trimmed == "" {
		return map[string]any{}
	}
	var value any
	if err := json.Unmarshal([]byte(trimmed), &value); err != nil {
		return trimmed
	}
	return value
}

// Stop marks a campaign as completed.
// POST /api/v1/accounts/:id/campaigns/:campaign_id/stop
func (h *CampaignHandler) Stop(c *gin.Context) {
	accountID := getAccountID(c)
	if accountID == 0 {
		response.AbortWithStatusError(c, http.StatusUnauthorized, response.ErrUnauthorized, "account not identified")
		return
	}

	id, err := strconv.ParseUint(c.Param("campaign_id"), 10, 32)
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid campaign ID")
		return
	}

	if svcErr := h.svc.Stop(c.Request.Context(), uint(id), accountID); svcErr != nil {
		applogger.L().Errorf("Stop campaign %d for account %d: %v", id, accountID, svcErr)
		handleServiceError(c, svcErr)
		return
	}

	response.OK(c, gin.H{"message": "campaign stopped successfully"})
}