// Copyright (c) 2026 Probo Inc <hello@probo.com>.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

package cookiebanner_v1

import (
	"encoding/json"
	"errors"
	"fmt"
	"net/http"
	"net/url"
	"strings"
	"time"

	"github.com/go-chi/chi/v5"
	"go.gearno.de/kit/httpserver"
	"go.gearno.de/kit/log"
	"go.probo.inc/probo/pkg/cookiebanner"
	"go.probo.inc/probo/pkg/coredata"
	"go.probo.inc/probo/pkg/geoloc"
	"go.probo.inc/probo/pkg/gid"
	"go.probo.inc/probo/pkg/server/api/clientip"
	"go.probo.inc/probo/pkg/server/jsonx"
	"go.probo.inc/probo/pkg/uri"
)

type Handler struct {
	logger          *log.Logger
	cookieBannerSvc *cookiebanner.Service
	geolocSvc       *geoloc.Service
}

func NewMux(
	logger *log.Logger,
	cookieBannerSvc *cookiebanner.Service,
	geolocSvc *geoloc.Service,
) *chi.Mux {
	h := &Handler{
		logger:          logger,
		cookieBannerSvc: cookieBannerSvc,
		geolocSvc:       geolocSvc,
	}

	r := chi.NewMux()
	r.Route("/{bannerID}", func(r chi.Router) {
		r.Use(newSDKVersionMiddleware())
		r.Use(newCORSMiddleware(logger, cookieBannerSvc))
		r.Get("/config", h.handleGetConfig)
		r.Get("/consents/{visitorID}", h.handleGetConsent)
		r.Post("/consents", h.handlePostConsent)
		r.Post("/detected-cookies", h.handleReportDetectedCookies)
		r.Post("/report", h.handleReportDetectedTrackers)
	})

	return r
}

func (h *Handler) handleGetConfig(w http.ResponseWriter, r *http.Request) {
	bannerID, err := gid.ParseGID(chi.URLParam(r, "bannerID"))
	if err != nil {
		jsonx.RenderBadRequest(w, fmt.Errorf("invalid banner id"))
		return
	}

	lang := r.URL.Query().Get("lang")
	sdkVersion := sdkVersionFromContext(r.Context())
	cc := h.resolveCountryCode(r)
	regulation, _ := cookiebanner.ResolveRegulation(cc)

	config, err := h.cookieBannerSvc.GetActiveBannerConfig(r.Context(), bannerID, lang, regulation, sdkVersion)
	if err != nil {
		if errors.Is(err, cookiebanner.ErrBannerNotFound) {
			jsonx.RenderNotFound(w, fmt.Errorf("banner not found"))
			return
		}

		if errors.Is(err, cookiebanner.ErrNoPublishedVersion) {
			jsonx.RenderNotFound(w, fmt.Errorf("no published version"))
			return
		}

		h.logger.ErrorCtx(r.Context(), "cannot get banner config", log.Error(err), log.String("sdk_version", sdkVersion))
		jsonx.RenderInternalServerError(w)

		return
	}

	httpserver.RenderJSON(w, http.StatusOK, config)
}

func (h *Handler) resolveCountryCode(r *http.Request) *coredata.CountryCode {
	ip := clientip.Extract(r)

	cc, err := h.geolocSvc.LookupCountry(r.Context(), ip)
	if err != nil {
		h.logger.ErrorCtx(
			r.Context(),
			"cannot resolve country for IP",
			log.Error(err),
			log.String("sdk_version", sdkVersionFromContext(r.Context())),
		)

		return nil
	}

	if cc == "" {
		return nil
	}

	return &cc
}

func (h *Handler) handleGetConsent(w http.ResponseWriter, r *http.Request) {
	bannerID, err := gid.ParseGID(chi.URLParam(r, "bannerID"))
	if err != nil {
		jsonx.RenderBadRequest(w, fmt.Errorf("invalid banner id"))
		return
	}

	visitorID := chi.URLParam(r, "visitorID")
	if visitorID == "" {
		jsonx.RenderBadRequest(w, fmt.Errorf("missing visitor id"))
		return
	}

	consent, err := h.cookieBannerSvc.GetVisitorConsent(r.Context(), bannerID, visitorID)
	if err != nil {
		if errors.Is(err, cookiebanner.ErrBannerNotFound) {
			jsonx.RenderNotFound(w, fmt.Errorf("banner not found"))
			return
		}

		if errors.Is(err, cookiebanner.ErrConsentNotFound) {
			jsonx.RenderNotFound(w, fmt.Errorf("consent not found"))
			return
		}

		h.logger.ErrorCtx(
			r.Context(),
			"cannot get visitor consent",
			log.Error(err),
			log.String("sdk_version", sdkVersionFromContext(r.Context())),
		)
		jsonx.RenderInternalServerError(w)

		return
	}

	httpserver.RenderJSON(w, http.StatusOK, consent)
}

type (
	postConsentBody struct {
		VisitorID   string                       `json:"visitor_id"`
		Version     int                          `json:"version"`
		Action      coredata.CookieConsentAction `json:"action"`
		ConsentData json.RawMessage              `json:"consent_data"`
	}

	postConsentResponse struct {
		ID        string    `json:"id"`
		VisitorID string    `json:"visitor_id"`
		Action    string    `json:"action"`
		CreatedAt time.Time `json:"created_at"`
	}
)

func (h *Handler) handlePostConsent(w http.ResponseWriter, r *http.Request) {
	bannerID, err := gid.ParseGID(chi.URLParam(r, "bannerID"))
	if err != nil {
		jsonx.RenderBadRequest(w, fmt.Errorf("invalid banner id"))
		return
	}

	var body postConsentBody
	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
		jsonx.RenderBadRequest(w, fmt.Errorf("invalid request body"))
		return
	}

	ip := clientip.Extract(r)
	ua := r.UserAgent()
	sdkVersion := sdkVersionFromContext(r.Context())
	cc := h.resolveCountryCode(r)
	regulation, regulationSource := cookiebanner.ResolveRegulation(cc)

	cm := coredata.CookieConsentMode(cookiebanner.ConsentModeForRegulation(regulation))

	req := cookiebanner.RecordConsentRequest{
		Version:          body.Version,
		VisitorID:        body.VisitorID,
		IPAddress:        &ip,
		UserAgent:        &ua,
		ConsentData:      body.ConsentData,
		Action:           body.Action,
		SdkVersion:       sdkVersion,
		Regulation:       &regulation,
		RegulationSource: regulationSource,
		CountryCode:      cc,
		ConsentMode:      &cm,
	}

	record, err := h.cookieBannerSvc.RecordConsent(r.Context(), bannerID, req)
	if err != nil {
		if errors.Is(err, cookiebanner.ErrBannerNotFound) {
			jsonx.RenderNotFound(w, fmt.Errorf("banner not found"))
			return
		}

		if errors.Is(err, cookiebanner.ErrVersionNotFound) || errors.Is(err, cookiebanner.ErrVersionNotPublished) {
			jsonx.RenderBadRequest(w, fmt.Errorf("invalid version"))
			return
		}

		h.logger.ErrorCtx(r.Context(), "cannot record consent", log.Error(err), log.String("sdk_version", sdkVersion))
		jsonx.RenderInternalServerError(w)

		return
	}

	httpserver.RenderJSON(
		w,
		http.StatusCreated,
		postConsentResponse{
			ID:        record.ID.String(),
			VisitorID: record.VisitorID,
			Action:    string(record.Action),
			CreatedAt: record.CreatedAt,
		},
	)
}

type detectedCookieEntry struct {
	Name          string  `json:"name"`
	MaxAgeSeconds *int    `json:"max_age_seconds"`
	Source        string  `json:"source"`
	InitiatorURL  *string `json:"initiator_url,omitempty"`
}

type reportDetectedCookiesBody struct {
	Cookies []detectedCookieEntry `json:"cookies"`
}

const (
	maxDetectedCookiesPerRequest = 100
	maxInitiatorURLLength        = 1024
)

// sanitizeInitiatorURL validates and normalises a script URL captured
// in the customer page's stack trace. It drops the value when it does
// not parse as an http(s) URL with a host, or when it exceeds the
// length cap. Returns nil for missing or invalid input.
func sanitizeInitiatorURL(raw *string) *string {
	if raw == nil {
		return nil
	}

	s := strings.TrimSpace(*raw)
	if s == "" || len(s) > maxInitiatorURLLength {
		return nil
	}

	u, err := url.Parse(s)
	if err != nil {
		return nil
	}

	if u.Scheme != "http" && u.Scheme != "https" {
		return nil
	}

	if u.Host == "" {
		return nil
	}

	return &s
}

func (h *Handler) handleReportDetectedCookies(w http.ResponseWriter, r *http.Request) {
	bannerID, err := gid.ParseGID(chi.URLParam(r, "bannerID"))
	if err != nil {
		jsonx.RenderBadRequest(w, fmt.Errorf("invalid banner id"))
		return
	}

	var body reportDetectedCookiesBody
	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
		jsonx.RenderBadRequest(w, fmt.Errorf("invalid request body"))
		return
	}

	if len(body.Cookies) == 0 {
		jsonx.RenderBadRequest(w, fmt.Errorf("cookies list is empty"))
		return
	}

	if len(body.Cookies) > maxDetectedCookiesPerRequest {
		jsonx.RenderBadRequest(w, fmt.Errorf("too many cookies, maximum is %d", maxDetectedCookiesPerRequest))
		return
	}

	detected := make([]cookiebanner.DetectedCookie, 0, len(body.Cookies))
	for _, c := range body.Cookies {
		name := strings.TrimSpace(c.Name)
		if name == "" {
			continue
		}

		var source coredata.CookieSource

		switch strings.TrimSpace(c.Source) {
		case "pre-existing":
			source = coredata.CookieSourcePreExisting
		case "http":
			source = coredata.CookieSourceHTTP
		default:
			source = coredata.CookieSourceScript
		}

		detected = append(
			detected,
			cookiebanner.DetectedCookie{
				Name:          name,
				MaxAgeSeconds: c.MaxAgeSeconds,
				Source:        source,
				InitiatorURL:  sanitizeInitiatorURL(c.InitiatorURL),
			},
		)
	}

	if len(detected) == 0 {
		jsonx.RenderBadRequest(w, fmt.Errorf("no valid cookie names provided"))
		return
	}

	req := cookiebanner.ReportDetectedCookiesRequest{
		Cookies: detected,
	}

	if err := h.cookieBannerSvc.ReportDetectedCookies(r.Context(), bannerID, req); err != nil {
		if errors.Is(err, cookiebanner.ErrBannerNotFound) {
			jsonx.RenderNotFound(w, fmt.Errorf("banner not found"))
			return
		}

		h.logger.ErrorCtx(
			r.Context(),
			"cannot report detected cookies",
			log.Error(err),
			log.String("sdk_version", sdkVersionFromContext(r.Context())),
		)
		jsonx.RenderInternalServerError(w)

		return
	}

	w.WriteHeader(http.StatusNoContent)
}

type detectedStorageEntry struct {
	Key          string  `json:"key"`
	StorageType  string  `json:"storage_type"`
	ValueSize    *int    `json:"value_size"`
	Source       string  `json:"source"`
	InitiatorURL *string `json:"initiator_url,omitempty"`
}

type detectedResourceEntry struct {
	URL          uri.URI `json:"url"`
	ResourceType string  `json:"resource_type"`
}

type reportDetectedTrackersBody struct {
	Cookies   []detectedCookieEntry   `json:"cookies"`
	Storage   []detectedStorageEntry  `json:"storage"`
	Resources []detectedResourceEntry `json:"resources"`
}

const maxDetectedTrackersPerRequest = 100

func (h *Handler) handleReportDetectedTrackers(w http.ResponseWriter, r *http.Request) {
	bannerID, err := gid.ParseGID(chi.URLParam(r, "bannerID"))
	if err != nil {
		jsonx.RenderBadRequest(w, fmt.Errorf("invalid banner id"))
		return
	}

	var body reportDetectedTrackersBody
	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
		jsonx.RenderBadRequest(w, fmt.Errorf("invalid request body"))
		return
	}

	total := len(body.Cookies) + len(body.Storage) + len(body.Resources)
	if total == 0 {
		jsonx.RenderBadRequest(w, fmt.Errorf("no items provided"))
		return
	}

	if total > maxDetectedTrackersPerRequest {
		jsonx.RenderBadRequest(w, fmt.Errorf("too many items, maximum is %d", maxDetectedTrackersPerRequest))
		return
	}

	var req cookiebanner.ReportDetectedTrackersRequest

	for _, c := range body.Cookies {
		name := strings.TrimSpace(c.Name)
		if name == "" {
			continue
		}

		var source coredata.CookieSource

		switch strings.TrimSpace(c.Source) {
		case "pre-existing":
			source = coredata.CookieSourcePreExisting
		case "http":
			source = coredata.CookieSourceHTTP
		case "extension":
			source = coredata.CookieSourceExtension
		default:
			source = coredata.CookieSourceScript
		}

		req.Cookies = append(
			req.Cookies,
			cookiebanner.DetectedCookie{
				Name:          name,
				MaxAgeSeconds: c.MaxAgeSeconds,
				Source:        source,
				InitiatorURL:  sanitizeInitiatorURL(c.InitiatorURL),
			},
		)
	}

	for _, s := range body.Storage {
		key := strings.TrimSpace(s.Key)
		if key == "" {
			continue
		}

		var storageType coredata.TrackerType

		switch strings.TrimSpace(s.StorageType) {
		case "local_storage":
			storageType = coredata.TrackerTypeLocalStorage
		case "session_storage":
			storageType = coredata.TrackerTypeSessionStorage
		case "indexed_db":
			storageType = coredata.TrackerTypeIndexedDB
		case "cache_storage":
			storageType = coredata.TrackerTypeCacheStorage
		default:
			continue
		}

		var source coredata.CookieSource

		switch strings.TrimSpace(s.Source) {
		case "pre-existing":
			source = coredata.CookieSourcePreExisting
		case "extension":
			source = coredata.CookieSourceExtension
		default:
			source = coredata.CookieSourceScript
		}

		req.Storage = append(
			req.Storage,
			cookiebanner.DetectedStorageItem{
				Key:          key,
				StorageType:  storageType,
				ValueSize:    s.ValueSize,
				Source:       &source,
				InitiatorURL: sanitizeInitiatorURL(s.InitiatorURL),
			},
		)
	}

	for _, res := range body.Resources {
		// The URI type validates scheme+host on UnmarshalText, so a
		// non-empty value here is guaranteed to be a valid URL. We
		// still need to reject the zero value, which occurs when the
		// `url` JSON field is missing.
		if res.URL == "" {
			continue
		}

		var resourceType coredata.TrackerResourceType

		switch strings.TrimSpace(res.ResourceType) {
		case "script":
			resourceType = coredata.TrackerResourceTypeScript
		case "iframe":
			resourceType = coredata.TrackerResourceTypeIframe
		case "image":
			resourceType = coredata.TrackerResourceTypeImage
		case "stylesheet":
			resourceType = coredata.TrackerResourceTypeStylesheet
		case "font":
			resourceType = coredata.TrackerResourceTypeFont
		case "beacon":
			resourceType = coredata.TrackerResourceTypeBeacon
		case "fetch":
			resourceType = coredata.TrackerResourceTypeFetch
		case "media":
			resourceType = coredata.TrackerResourceTypeMedia
		case "service_worker":
			resourceType = coredata.TrackerResourceTypeServiceWorker
		default:
			continue
		}

		req.Resources = append(
			req.Resources,
			cookiebanner.DetectedResourceItem{
				URL:          res.URL,
				ResourceType: resourceType,
			},
		)
	}

	if len(req.Cookies)+len(req.Storage)+len(req.Resources) == 0 {
		jsonx.RenderBadRequest(w, fmt.Errorf("no valid items provided"))
		return
	}

	if err := h.cookieBannerSvc.ReportDetectedTrackers(r.Context(), bannerID, req); err != nil {
		if errors.Is(err, cookiebanner.ErrBannerNotFound) {
			jsonx.RenderNotFound(w, fmt.Errorf("banner not found"))
			return
		}

		h.logger.ErrorCtx(r.Context(), "cannot report detected trackers", log.Error(err), log.String("sdk_version", sdkVersionFromContext(r.Context())))
		jsonx.RenderInternalServerError(w)

		return
	}

	w.WriteHeader(http.StatusNoContent)
}