package v1

// LINEChannelHandler handles LINE Official Account channel-specific configuration CRUD.
// Reference: This is a GoChat addition — Chatwoot does not have LINE channel support.
//
// LINE Messaging API: https://developers.line.biz/en/docs/messaging-api/
//
// gochat maps LINE channel operations to:
//   - POST   /api/v1/accounts/:id/channels/line_channel           → create LINE inbox
//   - GET    /api/v1/accounts/:id/channels/line_channel/:line_id  → get LINE channel
//   - PATCH  /api/v1/accounts/:id/channels/line_channel/:line_id  → update LINE channel
//   - DELETE /api/v1/accounts/:id/channels/line_channel/:line_id  → delete LINE channel
//   - GET    /api/v1/accounts/:id/channels/line_channel           → list LINE channels

import (
	"net/http"

	"github.com/gin-gonic/gin"

	pkgvalidator "github.com/gochat/gochat/pkg/validator"

	linechannel "github.com/gochat/gochat/internal/channel/line"
	channelmodel "github.com/gochat/gochat/internal/model/channel"
	"github.com/gochat/gochat/internal/repository"
	"github.com/gochat/gochat/internal/service"
	applogger "github.com/gochat/gochat/pkg/logger"
)

// LINEChannelHandler handles LINE Official Account channel management.
// Follows FacebookChannelHandler pattern: uses top-level ChannelLINEService for CRUD,
// internal LineProvider for webhook setup via OnCreate.
type LINEChannelHandler struct {
	lineChannelSvc *service.ChannelLINEService
	lineProvider   *linechannel.LineProvider
	inboxSvc       *service.InboxService
	lineRepo       *repository.ChannelLINERepo
}

// NewLINEChannelHandler creates a new LINE channel handler.
func NewLINEChannelHandler(
	lineChannelSvc *service.ChannelLINEService,
	lineProvider *linechannel.LineProvider,
	inboxSvc *service.InboxService,
	lineRepo *repository.ChannelLINERepo,
) *LINEChannelHandler {
	return &LINEChannelHandler{
		lineChannelSvc: lineChannelSvc,
		lineProvider:   lineProvider,
		inboxSvc:       inboxSvc,
		lineRepo:       lineRepo,
	}
}

// === Create ===

// CreateLINEChannelRequest is the DTO for creating a LINE channel.
type CreateLINEChannelRequest struct {
	ChannelID          string `json:"channel_id" validate:"required"`
	Name               string `json:"name" validate:"required"`
	ChannelAccessToken string `json:"channel_access_token" validate:"required"`
	ChannelSecret      string `json:"channel_secret" validate:"required"`
}

// Create adds a new LINE channel and creates the associated inbox.
// POST /api/v1/accounts/:id/channels/line_channel
func (h *LINEChannelHandler) Create(c *gin.Context) {
	accountID := parseAccountIDParam(c)
	if accountID == 0 {
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid account_id"})
		return
	}

	var req CreateLINEChannelRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		applogger.L().Errorf("Failed to bind LINE channel create request: %v", err)
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid request body"})
		return
	}
	if err := pkgvalidator.ValidateStruct(req); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid request body"})
		return
	}
	if err := h.inboxSvc.EnsureCanCreateInbox(c.Request.Context(), accountID); err != nil {
		if renderInboxLimitExceeded(c, err) {
			return
		}
		c.JSON(http.StatusUnprocessableEntity, gin.H{"error": "failed to create inbox"})
		return
	}

	ch := &channelmodel.ChannelLINE{
		AccountID: accountID,
		ChannelID: req.ChannelID,
		Name:      req.Name,
	}

	if err := h.lineChannelSvc.Create(c.Request.Context(), ch); err != nil {
		applogger.L().Errorf("Failed to create LINE channel: %v", err)
		c.JSON(http.StatusUnprocessableEntity, gin.H{"error": "failed to create LINE channel"})
		return
	}

	// Create inbox for the LINE channel
	inboxReq := service.CreateInboxRequest{
		Name:        req.Name,
		ChannelType: "line",
		Enabled:     true,
		Channel:     lineCreateChannelConfig(req),
	}
	inbox, err := h.inboxSvc.Create(c.Request.Context(), accountID, inboxReq)
	if err != nil {
		applogger.L().Errorf("Failed to create inbox for LINE channel: %v", err)
		if delErr := h.lineChannelSvc.Delete(c.Request.Context(), ch.ID); delErr != nil {
			applogger.L().Warnf("Failed to rollback LINE channel after inbox creation failure: %v", delErr)
		}
		if renderInboxLimitExceeded(c, err) {
			return
		}
		c.JSON(http.StatusUnprocessableEntity, gin.H{"error": "failed to create inbox"})
		return
	}

	ch.InboxID = inbox.ID
	if err := h.lineChannelSvc.Update(c.Request.Context(), ch); err != nil {
		applogger.L().Errorf("Failed to update LINE channel with inbox_id: %v", err)
	}
	inbox, err = h.inboxSvc.BindChannel(c.Request.Context(), accountID, inbox.ID, ch.ID, inboxReq.Channel)
	if err != nil {
		applogger.L().Warnf("Failed to bind LINE inbox channel config: %v", err)
	}

	c.JSON(http.StatusOK, serializeInbox(inbox))
}

// === Get ===

// Get retrieves a LINE channel by ID.
// GET /api/v1/accounts/:id/channels/line_channel/:line_id
func (h *LINEChannelHandler) Get(c *gin.Context) {
	lineID, err := parseUintParam(c, "line_id")
	if err != nil {
		applogger.L().Errorf("Invalid line_id: %v", err)
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid line_id"})
		return
	}

	ch, err := h.lineChannelSvc.GetByID(c.Request.Context(), lineID)
	if err != nil {
		applogger.L().Errorf("Failed to get LINE channel: %v", err)
		c.JSON(http.StatusNotFound, gin.H{"error": "LINE channel not found"})
		return
	}

	c.JSON(http.StatusOK, h.serializeInboxForLINEChannel(c, ch))
}

// === Update ===

// UpdateLINEChannelRequest is the DTO for updating a LINE channel.
type UpdateLINEChannelRequest struct {
	Name               string `json:"name,omitempty"`
	ChannelAccessToken string `json:"channel_access_token,omitempty"`
	ChannelSecret      string `json:"channel_secret,omitempty"`
}

// Update modifies an existing LINE channel.
// PATCH /api/v1/accounts/:id/channels/line_channel/:line_id
func (h *LINEChannelHandler) Update(c *gin.Context) {
	accountID := parseAccountIDParam(c)
	if accountID == 0 {
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid account_id"})
		return
	}

	lineID, err := parseUintParam(c, "line_id")
	if err != nil {
		applogger.L().Errorf("Invalid line_id: %v", err)
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid line_id"})
		return
	}

	ch, err := h.lineChannelSvc.GetByID(c.Request.Context(), lineID)
	if err != nil {
		applogger.L().Errorf("Failed to get LINE channel: %v", err)
		c.JSON(http.StatusNotFound, gin.H{"error": "LINE channel not found"})
		return
	}

	if ch.AccountID != accountID {
		c.JSON(http.StatusForbidden, gin.H{"error": "channel does not belong to this account"})
		return
	}

	var req UpdateLINEChannelRequest
	if err := c.ShouldBindJSON(&req); err != nil {
		applogger.L().Errorf("Failed to bind LINE channel update request: %v", err)
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid request body"})
		return
	}

	if req.Name != "" {
		ch.Name = req.Name
	}

	if err := h.lineChannelSvc.Update(c.Request.Context(), ch); err != nil {
		applogger.L().Errorf("Failed to update LINE channel: %v", err)
		c.JSON(http.StatusUnprocessableEntity, gin.H{"error": "failed to update LINE channel"})
		return
	}
	if req.Name != "" {
		if _, inboxErr := h.inboxSvc.Update(c.Request.Context(), accountID, ch.InboxID, service.UpdateInboxRequest{Name: req.Name}); inboxErr != nil {
			applogger.L().Warnf("Failed to update LINE inbox name: %v", inboxErr)
		}
	}
	inbox, bindErr := h.inboxSvc.BindChannel(c.Request.Context(), accountID, ch.InboxID, ch.ID, lineUpdateChannelConfig(req, ch))
	if bindErr != nil {
		applogger.L().Warnf("Failed to update LINE inbox channel config: %v", bindErr)
		c.JSON(http.StatusOK, h.serializeInboxForLINEChannel(c, ch))
		return
	}

	c.JSON(http.StatusOK, serializeInbox(inbox))
}

// === Delete ===

// Delete removes a LINE channel and its associated inbox.
// DELETE /api/v1/accounts/:id/channels/line_channel/:line_id
func (h *LINEChannelHandler) Delete(c *gin.Context) {
	accountID := parseAccountIDParam(c)
	if accountID == 0 {
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid account_id"})
		return
	}

	lineID, err := parseUintParam(c, "line_id")
	if err != nil {
		applogger.L().Errorf("Invalid line_id: %v", err)
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid line_id"})
		return
	}

	ch, err := h.lineChannelSvc.GetByID(c.Request.Context(), lineID)
	if err != nil {
		applogger.L().Errorf("Failed to get LINE channel: %v", err)
		c.JSON(http.StatusNotFound, gin.H{"error": "LINE channel not found"})
		return
	}

	if ch.AccountID != accountID {
		c.JSON(http.StatusForbidden, gin.H{"error": "channel does not belong to this account"})
		return
	}

	// Delete inbox first
	if ch.InboxID > 0 {
		if err := h.inboxSvc.Delete(c.Request.Context(), ch.InboxID); err != nil {
			applogger.L().Errorf("Failed to delete inbox for LINE channel: %v", err)
		}
	}

	if err := h.lineChannelSvc.Delete(c.Request.Context(), lineID); err != nil {
		applogger.L().Errorf("Failed to delete LINE channel: %v", err)
		c.JSON(http.StatusUnprocessableEntity, gin.H{"error": "failed to delete LINE channel"})
		return
	}

	c.Status(http.StatusOK)
}

// === List ===

// List retrieves all LINE channels for an account.
// GET /api/v1/accounts/:id/channels/line_channel
func (h *LINEChannelHandler) List(c *gin.Context) {
	accountID := parseAccountIDParam(c)
	if accountID == 0 {
		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid account_id"})
		return
	}

	channels, err := h.lineChannelSvc.List(c.Request.Context())
	if err != nil {
		applogger.L().Errorf("Failed to list LINE channels: %v", err)
		c.JSON(http.StatusUnprocessableEntity, gin.H{"error": "failed to list LINE channels"})
		return
	}

	payload := make([]map[string]any, 0, len(channels))
	for i := range channels {
		if channels[i].AccountID == accountID {
			payload = append(payload, h.serializeInboxForLINEChannel(c, &channels[i]))
		}
	}
	c.JSON(http.StatusOK, gin.H{"payload": payload})
}

func (h *LINEChannelHandler) serializeInboxForLINEChannel(c *gin.Context, ch *channelmodel.ChannelLINE) map[string]any {
	if ch != nil && ch.InboxID > 0 {
		if inbox, err := h.inboxSvc.GetByAccountAndID(c.Request.Context(), ch.AccountID, ch.InboxID); err == nil {
			return serializeInbox(inbox)
		}
	}
	return gin.H{"id": ch.ID, "account_id": ch.AccountID, "inbox_id": ch.InboxID, "channel_id": ch.ChannelID, "name": ch.Name}
}

func lineChannelConfigFromModel(ch *channelmodel.ChannelLINE) map[string]any {
	return map[string]any{
		"line_channel_id": ch.ChannelID,
		"channel_id":      ch.ChannelID,
	}
}

func lineCreateChannelConfig(req CreateLINEChannelRequest) map[string]any {
	return map[string]any{
		"line_channel_id":      req.ChannelID,
		"line_channel_token":   req.ChannelAccessToken,
		"line_channel_secret":  req.ChannelSecret,
		"channel_id":           req.ChannelID,
		"channel_access_token": req.ChannelAccessToken,
		"channel_secret":       req.ChannelSecret,
	}
}

func lineUpdateChannelConfig(req UpdateLINEChannelRequest, ch *channelmodel.ChannelLINE) map[string]any {
	config := lineChannelConfigFromModel(ch)
	if req.ChannelAccessToken != "" {
		config["line_channel_token"] = req.ChannelAccessToken
		config["channel_access_token"] = req.ChannelAccessToken
	}
	if req.ChannelSecret != "" {
		config["line_channel_secret"] = req.ChannelSecret
		config["channel_secret"] = req.ChannelSecret
	}
	return config
}