// SPDX-License-Identifier: AGPL-3.0-or-later

package handler

import (
	"encoding/json"
	"io/fs"
	"net/http"
	"net/url"
	"strings"

	"kode.naiv.no/olemd/favoritter/internal/middleware"
	"kode.naiv.no/olemd/favoritter/internal/render"
	"kode.naiv.no/olemd/favoritter/web"
)

// initPWACache pre-computes the manifest JSON and service worker JS
// so they can be served without per-request allocations.
func (h *Handler) initPWACache() {
	bp := h.deps.Config.BasePath

	manifest := map[string]any{
		"name":             h.deps.Config.SiteName,
		"short_name":       h.deps.Config.SiteName,
		"description":      "Lagre og del dine favoritter",
		"start_url":        bp + "/",
		"scope":            bp + "/",
		"display":          "standalone",
		"background_color": "#ffffff",
		"theme_color":      "#1095c1",
		"icons": []map[string]any{
			{"src": bp + "/static/icons/icon-192.png", "sizes": "192x192", "type": "image/png"},
			{"src": bp + "/static/icons/icon-512.png", "sizes": "512x512", "type": "image/png"},
			{"src": bp + "/static/icons/icon-512-maskable.png", "sizes": "512x512", "type": "image/png", "purpose": "maskable"},
		},
		"share_target": map[string]any{
			"action": bp + "/share",
			"method": "GET",
			"params": map[string]string{
				"url":   "url",
				"text":  "text",
				"title": "title",
			},
		},
	}
	h.manifestJSON, _ = json.Marshal(manifest)

	staticFS, err := fs.Sub(web.StaticFS, "static")
	if err == nil {
		if data, err := fs.ReadFile(staticFS, "sw.js"); err == nil {
			h.swJS = []byte(strings.ReplaceAll(string(data), "{{BASE_PATH}}", bp))
		}
	}
}

// handleManifest serves the pre-computed Web App Manifest.
func (h *Handler) handleManifest(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/manifest+json")
	w.Write(h.manifestJSON)
}

// handleServiceWorker serves the pre-computed service worker JS.
func (h *Handler) handleServiceWorker(w http.ResponseWriter, r *http.Request) {
	w.Header().Set("Content-Type", "application/javascript")
	w.Header().Set("Cache-Control", "no-cache")
	w.Write(h.swJS)
}

// handleShare receives Android share intents via the Web Share Target API
// and redirects to the new-fave form with pre-filled values.
// Uses GET to avoid CSRF issues (Android cannot provide CSRF tokens).
func (h *Handler) handleShare(w http.ResponseWriter, r *http.Request) {
	sharedURL := r.URL.Query().Get("url")
	sharedTitle := r.URL.Query().Get("title")
	sharedText := r.URL.Query().Get("text")

	// Many Android apps send the URL in the "text" field instead of "url".
	if sharedURL == "" && sharedText != "" {
		sharedURL = extractURL(sharedText)
		if sharedURL != "" {
			sharedText = strings.TrimSpace(strings.Replace(sharedText, sharedURL, "", 1))
		}
	}

	description := sharedTitle
	if description == "" && sharedText != "" {
		description = sharedText
		sharedText = ""
	}

	target := h.deps.Config.BasePath + "/faves/new?"
	params := url.Values{}
	if sharedURL != "" {
		params.Set("url", sharedURL)
	}
	if description != "" {
		params.Set("description", description)
	}
	if sharedText != "" {
		params.Set("notes", sharedText)
	}

	http.Redirect(w, r, target+params.Encode(), http.StatusSeeOther)
}

// handleFaveNewPreFill shows the new fave form, optionally pre-filled
// from query parameters (used by share target and bookmarklets).
func (h *Handler) handleFaveNewPreFill(w http.ResponseWriter, r *http.Request) {
	user := middleware.UserFromContext(r.Context())

	h.deps.Renderer.Page(w, r, "fave_form", render.PageData{
		Title: "Ny favoritt",
		Data: map[string]any{
			"IsNew":          true,
			"DefaultPrivacy": user.DefaultFavePrivacy,
			"Description":    r.URL.Query().Get("description"),
			"URL":            r.URL.Query().Get("url"),
			"Notes":          r.URL.Query().Get("notes"),
		},
	})
}

// extractURL finds the first http:// or https:// URL in a string.
func extractURL(s string) string {
	for _, word := range strings.Fields(s) {
		if strings.HasPrefix(word, "http://") || strings.HasPrefix(word, "https://") {
			return word
		}
	}
	return ""
}