package handlers

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

	"github.com/go-chi/chi"
	"github.com/google/uuid"
	"sneak.berlin/go/webhooker/internal/database"
)

// WebhookListItem holds data for the webhook list view.
type WebhookListItem struct {
	database.Webhook
	EntrypointCount int64
	TargetCount     int64
	EventCount      int64
}

// HandleSourceList shows a list of user's webhooks.
func (h *Handlers) HandleSourceList() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		userID, ok := h.getUserID(r)
		if !ok {
			http.Redirect(w, r, "/pages/login", http.StatusSeeOther)
			return
		}

		var webhooks []database.Webhook
		if err := h.db.DB().Where("user_id = ?", userID).Order("created_at DESC").Find(&webhooks).Error; err != nil {
			h.log.Error("failed to list webhooks", "error", err)
			http.Error(w, "Internal server error", http.StatusInternalServerError)
			return
		}

		// Build list items with counts
		items := make([]WebhookListItem, len(webhooks))
		for i := range webhooks {
			items[i].Webhook = webhooks[i]
			h.db.DB().Model(&database.Entrypoint{}).Where("webhook_id = ?", webhooks[i].ID).Count(&items[i].EntrypointCount)
			h.db.DB().Model(&database.Target{}).Where("webhook_id = ?", webhooks[i].ID).Count(&items[i].TargetCount)
			h.db.DB().Model(&database.Event{}).Where("webhook_id = ?", webhooks[i].ID).Count(&items[i].EventCount)
		}

		data := map[string]interface{}{
			"Webhooks": items,
		}
		h.renderTemplate(w, r, "sources_list.html", data)
	}
}

// HandleSourceCreate shows the form to create a new webhook.
func (h *Handlers) HandleSourceCreate() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		data := map[string]interface{}{
			"Error": "",
		}
		h.renderTemplate(w, r, "sources_new.html", data)
	}
}

// HandleSourceCreateSubmit handles the webhook creation form submission.
func (h *Handlers) HandleSourceCreateSubmit() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		userID, ok := h.getUserID(r)
		if !ok {
			http.Redirect(w, r, "/pages/login", http.StatusSeeOther)
			return
		}

		if err := r.ParseForm(); err != nil {
			http.Error(w, "Bad request", http.StatusBadRequest)
			return
		}

		name := r.FormValue("name")
		description := r.FormValue("description")
		retentionStr := r.FormValue("retention_days")

		if name == "" {
			data := map[string]interface{}{
				"Error": "Name is required",
			}
			w.WriteHeader(http.StatusBadRequest)
			h.renderTemplate(w, r, "sources_new.html", data)
			return
		}

		retentionDays := 30
		if retentionStr != "" {
			if v, err := strconv.Atoi(retentionStr); err == nil && v > 0 {
				retentionDays = v
			}
		}

		tx := h.db.DB().Begin()
		if tx.Error != nil {
			h.log.Error("failed to begin transaction", "error", tx.Error)
			http.Error(w, "Internal server error", http.StatusInternalServerError)
			return
		}

		webhook := &database.Webhook{
			UserID:        userID,
			Name:          name,
			Description:   description,
			RetentionDays: retentionDays,
		}

		if err := tx.Create(webhook).Error; err != nil {
			tx.Rollback()
			h.log.Error("failed to create webhook", "error", err)
			http.Error(w, "Internal server error", http.StatusInternalServerError)
			return
		}

		// Auto-create one entrypoint
		entrypoint := &database.Entrypoint{
			WebhookID:   webhook.ID,
			Path:        uuid.New().String(),
			Description: "Default entrypoint",
			Active:      true,
		}

		if err := tx.Create(entrypoint).Error; err != nil {
			tx.Rollback()
			h.log.Error("failed to create entrypoint", "error", err)
			http.Error(w, "Internal server error", http.StatusInternalServerError)
			return
		}

		if err := tx.Commit().Error; err != nil {
			h.log.Error("failed to commit transaction", "error", err)
			http.Error(w, "Internal server error", http.StatusInternalServerError)
			return
		}

		h.log.Info("webhook created",
			"webhook_id", webhook.ID,
			"name", name,
			"user_id", userID,
		)

		http.Redirect(w, r, "/source/"+webhook.ID, http.StatusSeeOther)
	}
}

// HandleSourceDetail shows details for a specific webhook.
func (h *Handlers) HandleSourceDetail() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		userID, ok := h.getUserID(r)
		if !ok {
			http.Redirect(w, r, "/pages/login", http.StatusSeeOther)
			return
		}

		sourceID := chi.URLParam(r, "sourceID")

		var webhook database.Webhook
		if err := h.db.DB().Where("id = ? AND user_id = ?", sourceID, userID).First(&webhook).Error; err != nil {
			http.NotFound(w, r)
			return
		}

		var entrypoints []database.Entrypoint
		h.db.DB().Where("webhook_id = ?", webhook.ID).Find(&entrypoints)

		var targets []database.Target
		h.db.DB().Where("webhook_id = ?", webhook.ID).Find(&targets)

		// Recent events with delivery info
		var events []database.Event
		h.db.DB().Where("webhook_id = ?", webhook.ID).Order("created_at DESC").Limit(20).Find(&events)

		// Build host URL for display
		host := r.Host
		scheme := "https"
		if r.TLS == nil {
			scheme = "http"
		}
		// Check X-Forwarded headers
		if fwdProto := r.Header.Get("X-Forwarded-Proto"); fwdProto != "" {
			scheme = fwdProto
		}

		data := map[string]interface{}{
			"Webhook":     webhook,
			"Entrypoints": entrypoints,
			"Targets":     targets,
			"Events":      events,
			"BaseURL":     scheme + "://" + host,
		}
		h.renderTemplate(w, r, "source_detail.html", data)
	}
}

// HandleSourceEdit shows the form to edit a webhook.
func (h *Handlers) HandleSourceEdit() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		userID, ok := h.getUserID(r)
		if !ok {
			http.Redirect(w, r, "/pages/login", http.StatusSeeOther)
			return
		}

		sourceID := chi.URLParam(r, "sourceID")

		var webhook database.Webhook
		if err := h.db.DB().Where("id = ? AND user_id = ?", sourceID, userID).First(&webhook).Error; err != nil {
			http.NotFound(w, r)
			return
		}

		data := map[string]interface{}{
			"Webhook": webhook,
			"Error":   "",
		}
		h.renderTemplate(w, r, "source_edit.html", data)
	}
}

// HandleSourceEditSubmit handles the webhook edit form submission.
func (h *Handlers) HandleSourceEditSubmit() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		userID, ok := h.getUserID(r)
		if !ok {
			http.Redirect(w, r, "/pages/login", http.StatusSeeOther)
			return
		}

		sourceID := chi.URLParam(r, "sourceID")

		var webhook database.Webhook
		if err := h.db.DB().Where("id = ? AND user_id = ?", sourceID, userID).First(&webhook).Error; err != nil {
			http.NotFound(w, r)
			return
		}

		if err := r.ParseForm(); err != nil {
			http.Error(w, "Bad request", http.StatusBadRequest)
			return
		}

		name := r.FormValue("name")
		if name == "" {
			data := map[string]interface{}{
				"Webhook": webhook,
				"Error":   "Name is required",
			}
			w.WriteHeader(http.StatusBadRequest)
			h.renderTemplate(w, r, "source_edit.html", data)
			return
		}

		webhook.Name = name
		webhook.Description = r.FormValue("description")
		if retStr := r.FormValue("retention_days"); retStr != "" {
			if v, err := strconv.Atoi(retStr); err == nil && v > 0 {
				webhook.RetentionDays = v
			}
		}

		if err := h.db.DB().Save(&webhook).Error; err != nil {
			h.log.Error("failed to update webhook", "error", err)
			http.Error(w, "Internal server error", http.StatusInternalServerError)
			return
		}

		http.Redirect(w, r, "/source/"+webhook.ID, http.StatusSeeOther)
	}
}

// HandleSourceDelete handles webhook deletion (soft delete).
func (h *Handlers) HandleSourceDelete() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		userID, ok := h.getUserID(r)
		if !ok {
			http.Redirect(w, r, "/pages/login", http.StatusSeeOther)
			return
		}

		sourceID := chi.URLParam(r, "sourceID")

		var webhook database.Webhook
		if err := h.db.DB().Where("id = ? AND user_id = ?", sourceID, userID).First(&webhook).Error; err != nil {
			http.NotFound(w, r)
			return
		}

		tx := h.db.DB().Begin()
		if tx.Error != nil {
			h.log.Error("failed to begin transaction", "error", tx.Error)
			http.Error(w, "Internal server error", http.StatusInternalServerError)
			return
		}

		// Soft-delete child records in dependency order (deepest first).

		// Collect event IDs for this webhook
		var eventIDs []string
		tx.Model(&database.Event{}).Where("webhook_id = ?", webhook.ID).Pluck("id", &eventIDs)

		if len(eventIDs) > 0 {
			// Collect delivery IDs for these events
			var deliveryIDs []string
			tx.Model(&database.Delivery{}).Where("event_id IN ?", eventIDs).Pluck("id", &deliveryIDs)

			if len(deliveryIDs) > 0 {
				// Soft-delete delivery results
				tx.Where("delivery_id IN ?", deliveryIDs).Delete(&database.DeliveryResult{})
			}

			// Soft-delete deliveries
			tx.Where("event_id IN ?", eventIDs).Delete(&database.Delivery{})
		}

		// Soft-delete events, entrypoints, targets, and the webhook itself
		tx.Where("webhook_id = ?", webhook.ID).Delete(&database.Event{})
		tx.Where("webhook_id = ?", webhook.ID).Delete(&database.Entrypoint{})
		tx.Where("webhook_id = ?", webhook.ID).Delete(&database.Target{})
		tx.Delete(&webhook)

		if err := tx.Commit().Error; err != nil {
			h.log.Error("failed to commit deletion", "error", err)
			http.Error(w, "Internal server error", http.StatusInternalServerError)
			return
		}

		h.log.Info("webhook deleted", "webhook_id", webhook.ID, "user_id", userID)
		http.Redirect(w, r, "/sources", http.StatusSeeOther)
	}
}

// HandleSourceLogs shows the request/response logs for a webhook.
func (h *Handlers) HandleSourceLogs() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		userID, ok := h.getUserID(r)
		if !ok {
			http.Redirect(w, r, "/pages/login", http.StatusSeeOther)
			return
		}

		sourceID := chi.URLParam(r, "sourceID")

		var webhook database.Webhook
		if err := h.db.DB().Where("id = ? AND user_id = ?", sourceID, userID).First(&webhook).Error; err != nil {
			http.NotFound(w, r)
			return
		}

		// Pagination
		page := 1
		if p := r.URL.Query().Get("page"); p != "" {
			if v, err := strconv.Atoi(p); err == nil && v > 0 {
				page = v
			}
		}
		perPage := 25
		offset := (page - 1) * perPage

		var totalEvents int64
		h.db.DB().Model(&database.Event{}).Where("webhook_id = ?", webhook.ID).Count(&totalEvents)

		var events []database.Event
		h.db.DB().Where("webhook_id = ?", webhook.ID).
			Order("created_at DESC").
			Offset(offset).
			Limit(perPage).
			Find(&events)

		// Load deliveries for each event
		type EventWithDeliveries struct {
			database.Event
			Deliveries []database.Delivery
		}
		eventsWithDeliveries := make([]EventWithDeliveries, len(events))
		for i := range events {
			eventsWithDeliveries[i].Event = events[i]
			h.db.DB().Where("event_id = ?", events[i].ID).Preload("Target").Find(&eventsWithDeliveries[i].Deliveries)
		}

		totalPages := int(totalEvents) / perPage
		if int(totalEvents)%perPage != 0 {
			totalPages++
		}

		data := map[string]interface{}{
			"Webhook":     webhook,
			"Events":      eventsWithDeliveries,
			"Page":        page,
			"TotalPages":  totalPages,
			"TotalEvents": totalEvents,
			"HasPrev":     page > 1,
			"HasNext":     page < totalPages,
			"PrevPage":    page - 1,
			"NextPage":    page + 1,
		}
		h.renderTemplate(w, r, "source_logs.html", data)
	}
}

// HandleEntrypointCreate handles adding a new entrypoint to a webhook.
func (h *Handlers) HandleEntrypointCreate() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		userID, ok := h.getUserID(r)
		if !ok {
			http.Redirect(w, r, "/pages/login", http.StatusSeeOther)
			return
		}

		sourceID := chi.URLParam(r, "sourceID")

		// Verify ownership
		var webhook database.Webhook
		if err := h.db.DB().Where("id = ? AND user_id = ?", sourceID, userID).First(&webhook).Error; err != nil {
			http.NotFound(w, r)
			return
		}

		if err := r.ParseForm(); err != nil {
			http.Error(w, "Bad request", http.StatusBadRequest)
			return
		}

		description := r.FormValue("description")

		entrypoint := &database.Entrypoint{
			WebhookID:   webhook.ID,
			Path:        uuid.New().String(),
			Description: description,
			Active:      true,
		}

		if err := h.db.DB().Create(entrypoint).Error; err != nil {
			h.log.Error("failed to create entrypoint", "error", err)
			http.Error(w, "Internal server error", http.StatusInternalServerError)
			return
		}

		http.Redirect(w, r, "/source/"+webhook.ID, http.StatusSeeOther)
	}
}

// HandleTargetCreate handles adding a new target to a webhook.
func (h *Handlers) HandleTargetCreate() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		userID, ok := h.getUserID(r)
		if !ok {
			http.Redirect(w, r, "/pages/login", http.StatusSeeOther)
			return
		}

		sourceID := chi.URLParam(r, "sourceID")

		var webhook database.Webhook
		if err := h.db.DB().Where("id = ? AND user_id = ?", sourceID, userID).First(&webhook).Error; err != nil {
			http.NotFound(w, r)
			return
		}

		if err := r.ParseForm(); err != nil {
			http.Error(w, "Bad request", http.StatusBadRequest)
			return
		}

		name := r.FormValue("name")
		targetType := database.TargetType(r.FormValue("type"))
		url := r.FormValue("url")
		maxRetriesStr := r.FormValue("max_retries")

		if name == "" {
			http.Error(w, "Name is required", http.StatusBadRequest)
			return
		}

		// Validate target type
		switch targetType {
		case database.TargetTypeHTTP, database.TargetTypeRetry, database.TargetTypeDatabase, database.TargetTypeLog:
			// valid
		default:
			http.Error(w, "Invalid target type", http.StatusBadRequest)
			return
		}

		// Build config JSON for HTTP-based targets
		var configJSON string
		if targetType == database.TargetTypeHTTP || targetType == database.TargetTypeRetry {
			if url == "" {
				http.Error(w, "URL is required for HTTP targets", http.StatusBadRequest)
				return
			}
			cfg := map[string]interface{}{
				"url": url,
			}
			configBytes, err := json.Marshal(cfg)
			if err != nil {
				http.Error(w, "Internal server error", http.StatusInternalServerError)
				return
			}
			configJSON = string(configBytes)
		}

		maxRetries := 5
		if maxRetriesStr != "" {
			if v, err := strconv.Atoi(maxRetriesStr); err == nil && v > 0 {
				maxRetries = v
			}
		}

		target := &database.Target{
			WebhookID:  webhook.ID,
			Name:       name,
			Type:       targetType,
			Active:     true,
			Config:     configJSON,
			MaxRetries: maxRetries,
		}

		if err := h.db.DB().Create(target).Error; err != nil {
			h.log.Error("failed to create target", "error", err)
			http.Error(w, "Internal server error", http.StatusInternalServerError)
			return
		}

		http.Redirect(w, r, "/source/"+webhook.ID, http.StatusSeeOther)
	}
}

// HandleEntrypointDelete handles deleting an individual entrypoint.
func (h *Handlers) HandleEntrypointDelete() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		userID, ok := h.getUserID(r)
		if !ok {
			http.Redirect(w, r, "/pages/login", http.StatusSeeOther)
			return
		}

		sourceID := chi.URLParam(r, "sourceID")
		entrypointID := chi.URLParam(r, "entrypointID")

		// Verify webhook ownership
		var webhook database.Webhook
		if err := h.db.DB().Where("id = ? AND user_id = ?", sourceID, userID).First(&webhook).Error; err != nil {
			http.NotFound(w, r)
			return
		}

		// Delete entrypoint (must belong to this webhook)
		result := h.db.DB().Where("id = ? AND webhook_id = ?", entrypointID, webhook.ID).Delete(&database.Entrypoint{})
		if result.Error != nil {
			h.log.Error("failed to delete entrypoint", "error", result.Error)
			http.Error(w, "Internal server error", http.StatusInternalServerError)
			return
		}

		http.Redirect(w, r, "/source/"+webhook.ID, http.StatusSeeOther)
	}
}

// HandleEntrypointToggle handles toggling the active state of an entrypoint.
func (h *Handlers) HandleEntrypointToggle() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		userID, ok := h.getUserID(r)
		if !ok {
			http.Redirect(w, r, "/pages/login", http.StatusSeeOther)
			return
		}

		sourceID := chi.URLParam(r, "sourceID")
		entrypointID := chi.URLParam(r, "entrypointID")

		// Verify webhook ownership
		var webhook database.Webhook
		if err := h.db.DB().Where("id = ? AND user_id = ?", sourceID, userID).First(&webhook).Error; err != nil {
			http.NotFound(w, r)
			return
		}

		// Find the entrypoint
		var entrypoint database.Entrypoint
		if err := h.db.DB().Where("id = ? AND webhook_id = ?", entrypointID, webhook.ID).First(&entrypoint).Error; err != nil {
			http.NotFound(w, r)
			return
		}

		// Toggle active state
		entrypoint.Active = !entrypoint.Active
		if err := h.db.DB().Save(&entrypoint).Error; err != nil {
			h.log.Error("failed to toggle entrypoint", "error", err)
			http.Error(w, "Internal server error", http.StatusInternalServerError)
			return
		}

		http.Redirect(w, r, "/source/"+webhook.ID, http.StatusSeeOther)
	}
}

// HandleTargetDelete handles deleting an individual target.
func (h *Handlers) HandleTargetDelete() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		userID, ok := h.getUserID(r)
		if !ok {
			http.Redirect(w, r, "/pages/login", http.StatusSeeOther)
			return
		}

		sourceID := chi.URLParam(r, "sourceID")
		targetID := chi.URLParam(r, "targetID")

		// Verify webhook ownership
		var webhook database.Webhook
		if err := h.db.DB().Where("id = ? AND user_id = ?", sourceID, userID).First(&webhook).Error; err != nil {
			http.NotFound(w, r)
			return
		}

		// Delete target (must belong to this webhook)
		result := h.db.DB().Where("id = ? AND webhook_id = ?", targetID, webhook.ID).Delete(&database.Target{})
		if result.Error != nil {
			h.log.Error("failed to delete target", "error", result.Error)
			http.Error(w, "Internal server error", http.StatusInternalServerError)
			return
		}

		http.Redirect(w, r, "/source/"+webhook.ID, http.StatusSeeOther)
	}
}

// HandleTargetToggle handles toggling the active state of a target.
func (h *Handlers) HandleTargetToggle() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		userID, ok := h.getUserID(r)
		if !ok {
			http.Redirect(w, r, "/pages/login", http.StatusSeeOther)
			return
		}

		sourceID := chi.URLParam(r, "sourceID")
		targetID := chi.URLParam(r, "targetID")

		// Verify webhook ownership
		var webhook database.Webhook
		if err := h.db.DB().Where("id = ? AND user_id = ?", sourceID, userID).First(&webhook).Error; err != nil {
			http.NotFound(w, r)
			return
		}

		// Find the target
		var target database.Target
		if err := h.db.DB().Where("id = ? AND webhook_id = ?", targetID, webhook.ID).First(&target).Error; err != nil {
			http.NotFound(w, r)
			return
		}

		// Toggle active state
		target.Active = !target.Active
		if err := h.db.DB().Save(&target).Error; err != nil {
			h.log.Error("failed to toggle target", "error", err)
			http.Error(w, "Internal server error", http.StatusInternalServerError)
			return
		}

		http.Redirect(w, r, "/source/"+webhook.ID, http.StatusSeeOther)
	}
}

// getUserID extracts the user ID from the session.
func (h *Handlers) getUserID(r *http.Request) (string, bool) {
	sess, err := h.session.Get(r)
	if err != nil {
		return "", false
	}
	if !h.session.IsAuthenticated(sess) {
		return "", false
	}
	return h.session.GetUserID(sess)
}