package v1

import (
	"encoding/json"
	"net/http"
	"time"

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

// CannedResponseHandler handles CannedResponse CRUD + search endpoints.
// Reference: Chatwoot CannedResponsesController — CRUD + search by short_code/content
type CannedResponseHandler struct {
	svc *canned.CannedResponseService
}

type cannedResponseInput struct {
	ShortCode *string `json:"short_code"`
	Content   *string `json:"content"`
}

type cannedResponsePayload struct {
	ID        uint      `json:"id"`
	AccountID uint      `json:"account_id"`
	ShortCode string    `json:"short_code"`
	Content   string    `json:"content"`
	CreatedAt time.Time `json:"created_at"`
	UpdatedAt time.Time `json:"updated_at"`
}

// NewCannedResponseHandler creates a new CannedResponseHandler.
func NewCannedResponseHandler(svc *canned.CannedResponseService) *CannedResponseHandler {
	return &CannedResponseHandler{svc: svc}
}

func bindCannedResponseInput(c *gin.Context) (cannedResponseInput, error) {
	var body map[string]json.RawMessage
	if err := c.ShouldBindJSON(&body); err != nil {
		return cannedResponseInput{}, err
	}

	if raw, ok := body["canned_response"]; ok {
		var wrapped cannedResponseInput
		if err := json.Unmarshal(raw, &wrapped); err != nil {
			return cannedResponseInput{}, err
		}
		return wrapped, nil
	}

	var input cannedResponseInput
	if raw, ok := body["short_code"]; ok {
		if err := json.Unmarshal(raw, &input.ShortCode); err != nil {
			return cannedResponseInput{}, err
		}
	}
	if raw, ok := body["content"]; ok {
		if err := json.Unmarshal(raw, &input.Content); err != nil {
			return cannedResponseInput{}, err
		}
	}
	return input, nil
}

func serializeCannedResponse(cr canned.CannedResponse) cannedResponsePayload {
	return cannedResponsePayload{
		ID:        cr.ID,
		AccountID: cr.AccountID,
		ShortCode: cr.ShortCode,
		Content:   cr.Content,
		CreatedAt: cr.CreatedAt,
		UpdatedAt: cr.UpdatedAt,
	}
}

func serializeCannedResponses(responses []canned.CannedResponse) []cannedResponsePayload {
	payload := make([]cannedResponsePayload, 0, len(responses))
	for _, cr := range responses {
		payload = append(payload, serializeCannedResponse(cr))
	}
	return payload
}

// Create creates a new canned response.
// POST /api/v1/accounts/:account_id/canned_responses
// Reference: Chatwoot CannedResponsesController#create
func (h *CannedResponseHandler) Create(c *gin.Context) {
	accountID, err := parseUintParam(c, "account_id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid account_id")
		return
	}

	req, err := bindCannedResponseInput(c)
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrValidation, err.Error())
		return
	}
	if req.ShortCode == nil || *req.ShortCode == "" || req.Content == nil || *req.Content == "" {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrValidation, "short_code and content are required")
		return
	}

	cr := &canned.CannedResponse{
		AccountID: accountID,
		ShortCode: *req.ShortCode,
		Content:   *req.Content,
	}

	if err := h.svc.Create(c.Request.Context(), cr); err != nil {
		applogger.L().Errorf("Create canned response: %v", err)
		handleServiceError(c, err)
		return
	}

	c.JSON(http.StatusOK, serializeCannedResponse(*cr))
}

// Get retrieves a canned response by ID.
// GET /api/v1/accounts/:account_id/canned_responses/:id
// Reference: Chatwoot CannedResponsesController#show
func (h *CannedResponseHandler) Get(c *gin.Context) {
	id, err := parseUintParam(c, "id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid id")
		return
	}
	accountID, err := parseUintParam(c, "account_id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid account_id")
		return
	}

	cr, svcErr := h.svc.GetByAccountAndID(c.Request.Context(), accountID, id)
	if svcErr != nil {
		handleServiceError(c, svcErr)
		return
	}

	c.JSON(http.StatusOK, serializeCannedResponse(*cr))
}

// Update updates a canned response.
// PUT /api/v1/accounts/:account_id/canned_responses/:id
// Reference: Chatwoot CannedResponsesController#update
func (h *CannedResponseHandler) Update(c *gin.Context) {
	id, err := parseUintParam(c, "id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid id")
		return
	}
	accountID, err := parseUintParam(c, "account_id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid account_id")
		return
	}

	req, err := bindCannedResponseInput(c)
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrValidation, err.Error())
		return
	}

	updates := map[string]interface{}{}
	if req.ShortCode != nil {
		updates["short_code"] = *req.ShortCode
	}
	if req.Content != nil {
		updates["content"] = *req.Content
	}

	if len(updates) == 0 {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrValidation, "no fields to update")
		return
	}

	if svcErr := h.svc.UpdateByAccountAndID(c.Request.Context(), accountID, id, updates); svcErr != nil {
		applogger.L().Errorf("Update canned response: %v", svcErr)
		handleServiceError(c, svcErr)
		return
	}

	cr, svcErr := h.svc.GetByAccountAndID(c.Request.Context(), accountID, id)
	if svcErr != nil {
		handleServiceError(c, svcErr)
		return
	}

	c.JSON(http.StatusOK, serializeCannedResponse(*cr))
}

// Delete soft-deletes a canned response.
// DELETE /api/v1/accounts/:account_id/canned_responses/:id
// Reference: Chatwoot CannedResponsesController#destroy
func (h *CannedResponseHandler) Delete(c *gin.Context) {
	id, err := parseUintParam(c, "id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid id")
		return
	}
	accountID, err := parseUintParam(c, "account_id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid account_id")
		return
	}

	if svcErr := h.svc.DeleteByAccountAndID(c.Request.Context(), accountID, id); svcErr != nil {
		applogger.L().Errorf("Delete canned response: %v", svcErr)
		handleServiceError(c, svcErr)
		return
	}

	c.Status(http.StatusOK)
}

// List returns all canned responses for an account.
// GET /api/v1/accounts/:account_id/canned_responses
// Reference: Chatwoot CannedResponsesController#index
func (h *CannedResponseHandler) List(c *gin.Context) {
	accountID, err := parseUintParam(c, "account_id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid account_id")
		return
	}

	searchQuery := c.Query("search")
	if searchQuery == "" {
		searchQuery = c.Query("q")
	}
	if searchQuery != "" {
		responses, svcErr := h.svc.Search(c.Request.Context(), accountID, searchQuery)
		if svcErr != nil {
			handleServiceError(c, svcErr)
			return
		}
		c.JSON(http.StatusOK, serializeCannedResponses(responses))
		return
	}

	responses, svcErr := h.svc.ListByAccount(c.Request.Context(), accountID)
	if svcErr != nil {
		handleServiceError(c, svcErr)
		return
	}

	c.JSON(http.StatusOK, serializeCannedResponses(responses))
}

// Search performs a ranked search over canned responses.
// GET /api/v1/accounts/:account_id/canned_responses/search?q=...
// Reference: Chatwoot CannedResponsesController#index with search parameter (order_by_search scope)
func (h *CannedResponseHandler) Search(c *gin.Context) {
	accountID, err := parseUintParam(c, "account_id")
	if err != nil {
		response.AbortWithStatusError(c, http.StatusBadRequest, response.ErrBadRequest, "invalid account_id")
		return
	}

	searchQuery := c.Query("search")
	if searchQuery == "" {
		searchQuery = c.Query("q")
	}
	responses, svcErr := h.svc.Search(c.Request.Context(), accountID, searchQuery)
	if svcErr != nil {
		handleServiceError(c, svcErr)
		return
	}

	c.JSON(http.StatusOK, serializeCannedResponses(responses))
}