package handlers

import (
	"fmt"
	"log/slog"
	"net/http"
	"strconv"
	"strings"

	"veola/internal/apify"
	"veola/internal/auth"
	"veola/internal/ebay"
	"veola/internal/email"
	"veola/internal/models"
	"veola/internal/ntfy"
	"veola/templates"
)

// settingsKeys are the non-secret operational settings editable from the
// Settings page. API credentials (Apify, eBay, ntfy, Resend) are deliberately
// NOT here — they are managed only in config.toml on the server, so the UI
// never reads or writes them. The Test buttons verify them.
var settingsKeys = []string{
	"ebay_daily_call_limit",
	"ntfy_base_url",
	"ntfy_default_topic",
	"global_poll_interval_minutes",
	"match_confidence_threshold",
	"apify_cost_per_call",
	"monthly_budget_usd",
}

func (a *App) settingsData(r *http.Request) (templates.SettingsData, error) {
	values, err := a.Store.GetAllSettings(r.Context())
	if err != nil {
		return templates.SettingsData{}, err
	}
	if values == nil {
		values = map[string]string{}
	}
	users, _ := a.Store.ListUsers(r.Context())
	cur := auth.CurrentUserFromRequest(r)
	ebayUsed, ebayLimit := a.Scheduler.EbayUsage(r.Context())
	apifyToday, apifyMonth, costPerCall, monthlyBudget := a.Scheduler.ApifyUsage(r.Context())
	return templates.SettingsData{
		Page:             a.page(r, "Settings", "settings"),
		Values:           values,
		IsAdmin:          cur != nil && cur.Role == models.RoleAdmin,
		Users:            users,
		EbayUsedToday:    ebayUsed,
		EbayDailyLimit:   ebayLimit,
		ApifyToday:       apifyToday,
		ApifyMonth:       apifyMonth,
		ApifyCostPerCall: costPerCall,
		MonthlyBudget:    monthlyBudget,
		ForwardAuthMode:  a.Cfg.Auth.ForwardAuthEnabled(),
	}, nil
}

// PostEmailPrefs lets the signed-in user set their own notification email and
// opt into deal-alert / weekly-digest email. Available to every user, not just
// admins (each user owns their own delivery prefs).
func (a *App) PostEmailPrefs(w http.ResponseWriter, r *http.Request) {
	cur := auth.CurrentUserFromRequest(r)
	if cur == nil {
		http.Redirect(w, r, "/login", http.StatusSeeOther)
		return
	}
	if err := r.ParseForm(); err != nil {
		http.Error(w, "bad form", http.StatusBadRequest)
		return
	}
	email := strings.TrimSpace(r.PostFormValue("email"))
	// In forward-auth mode, Authentik is the single source of truth for email
	// addresses — Veola never writes them. For a forward row this also preserves
	// the IdP match key (changing it would orphan the row on next sign-in); for
	// a break-glass local row it keeps email management centralized in Authentik.
	// Only the opt-in toggles are editable here. When forward-auth is off (pure
	// local deployment, no IdP), local users set their own Resend address.
	if a.Cfg.Auth.ForwardAuthEnabled() || cur.AuthSource == "forward" {
		email = cur.Email
	}
	dealAlerts := r.PostFormValue("email_deal_alerts") == "1"
	weeklyDigest := r.PostFormValue("email_weekly_digest") == "1"

	d, err := a.settingsData(r)
	if err != nil {
		a.serverError(w, r, err)
		return
	}
	if email == "" && (dealAlerts || weeklyDigest) {
		d.EmailError = "Set an email address to receive email notifications."
		render(w, r, templates.Settings(d))
		return
	}
	if err := a.Store.UpdateUserEmailPrefs(r.Context(), cur.ID, email, dealAlerts, weeklyDigest); err != nil {
		a.serverError(w, r, err)
		return
	}
	// Reflect the saved values immediately on the already-built data (CurrentUser
	// in d predates the write); no need to reassemble the whole settings page.
	if d.Page.CurrentUser != nil {
		d.Page.CurrentUser.Email = email
		d.Page.CurrentUser.EmailDealAlerts = dealAlerts
		d.Page.CurrentUser.EmailWeeklyDigest = weeklyDigest
	}
	d.EmailMsg = "Email preferences saved."
	render(w, r, templates.Settings(d))
}

// PostTestResend sends a test email to the admin's own address to verify the
// Resend configuration.
func (a *App) PostTestResend(w http.ResponseWriter, r *http.Request) {
	cur := auth.CurrentUserFromRequest(r)
	if cur == nil || cur.Role != models.RoleAdmin {
		http.Error(w, "forbidden", http.StatusForbidden)
		return
	}
	d, err := a.settingsData(r)
	if err != nil {
		a.serverError(w, r, err)
		return
	}
	apiKey := strings.TrimSpace(d.Values["resend_api_key"])
	if apiKey == "" {
		apiKey = a.Cfg.Resend.APIKey
	}
	from := a.Cfg.Resend.From
	to := ""
	if cur != nil {
		to = cur.Email
	}
	if to == "" {
		d.TestResendOK = "Set your notification email below first, then test."
		render(w, r, templates.Settings(d))
		return
	}
	client := email.New(apiKey, from)
	if err := client.Send(r.Context(), email.Message{
		To:      to,
		Subject: "Veola test email",
		HTML:    "<p>Test email from Veola settings. Resend is configured correctly.</p>",
		Text:    "Test email from Veola settings. Resend is configured correctly.",
	}); err != nil {
		d.TestResendOK = "Resend test failed: " + err.Error()
	} else {
		d.TestResendOK = "Sent a test email to " + to + "."
	}
	render(w, r, templates.Settings(d))
}

func (a *App) GetSettings(w http.ResponseWriter, r *http.Request) {
	d, err := a.settingsData(r)
	if err != nil {
		a.serverError(w, r, err)
		return
	}
	render(w, r, templates.Settings(d))
}

func (a *App) PostSettings(w http.ResponseWriter, r *http.Request) {
	cur := auth.CurrentUserFromRequest(r)
	if cur == nil || cur.Role != models.RoleAdmin {
		http.Error(w, "forbidden", http.StatusForbidden)
		return
	}
	if err := r.ParseForm(); err != nil {
		http.Error(w, "bad form", http.StatusBadRequest)
		return
	}
	for _, k := range settingsKeys {
		v := strings.TrimSpace(r.PostFormValue(k))
		if err := a.Store.SetSetting(r.Context(), k, v); err != nil {
			a.serverError(w, r, err)
			return
		}
	}
	http.Redirect(w, r, "/settings", http.StatusSeeOther)
}

func (a *App) PostPasswordChange(w http.ResponseWriter, r *http.Request) {
	cur := auth.CurrentUserFromRequest(r)
	if cur == nil {
		http.Redirect(w, r, "/login", http.StatusSeeOther)
		return
	}
	if err := r.ParseForm(); err != nil {
		http.Error(w, "bad form", http.StatusBadRequest)
		return
	}
	current := r.PostFormValue("current_password")
	next := r.PostFormValue("new_password")
	confirm := r.PostFormValue("new_password_confirm")

	d, err := a.settingsData(r)
	if err != nil {
		a.serverError(w, r, err)
		return
	}

	switch {
	case !auth.CheckPassword(cur.PasswordHash, current):
		d.PasswordError = "Current password is incorrect"
	case len(next) < auth.MinPasswordLen:
		d.PasswordError = fmt.Sprintf("New password must be at least %d characters", auth.MinPasswordLen)
	case next != confirm:
		d.PasswordError = "New passwords do not match"
	}
	if d.PasswordError != "" {
		render(w, r, templates.Settings(d))
		return
	}

	hash, err := auth.HashPassword(next)
	if err != nil {
		http.Error(w, "hash error", http.StatusInternalServerError)
		return
	}
	if err := a.Store.UpdateUserPassword(r.Context(), cur.ID, hash); err != nil {
		a.serverError(w, r, err)
		return
	}
	d.PasswordMsg = "Password updated"
	render(w, r, templates.Settings(d))
}

func (a *App) PostTestNtfy(w http.ResponseWriter, r *http.Request) {
	cur := auth.CurrentUserFromRequest(r)
	if cur == nil || cur.Role != models.RoleAdmin {
		http.Error(w, "forbidden", http.StatusForbidden)
		return
	}
	d, err := a.settingsData(r)
	if err != nil {
		a.serverError(w, r, err)
		return
	}
	baseURL := strings.TrimSpace(d.Values["ntfy_base_url"])
	if baseURL == "" {
		baseURL = a.Cfg.Ntfy.BaseURL
	}
	topic := strings.TrimSpace(d.Values["ntfy_default_topic"])
	if topic == "" {
		topic = a.Cfg.Ntfy.DefaultTopic
	}
	if baseURL == "" || topic == "" {
		d.TestNtfyOK = "Set ntfy base URL and default topic first."
		render(w, r, templates.Settings(d))
		return
	}
	client := ntfy.NewWithBasicAuth(baseURL, a.Cfg.Ntfy.Username, a.Cfg.Ntfy.Password)
	if err := client.Send(r.Context(), ntfy.Notification{
		Topic:    topic,
		Title:    "Veola test",
		Message:  "Test notification from Veola settings.",
		Priority: "default",
		Tags:     []string{"white_check_mark"},
	}); err != nil {
		d.TestNtfyOK = "Ntfy test failed: " + err.Error()
	} else {
		d.TestNtfyOK = fmt.Sprintf("Sent test notification to %s/%s", baseURL, topic)
	}
	render(w, r, templates.Settings(d))
}

func (a *App) PostTestApify(w http.ResponseWriter, r *http.Request) {
	cur := auth.CurrentUserFromRequest(r)
	if cur == nil || cur.Role != models.RoleAdmin {
		http.Error(w, "forbidden", http.StatusForbidden)
		return
	}
	d, err := a.settingsData(r)
	if err != nil {
		a.serverError(w, r, err)
		return
	}
	apiKey := strings.TrimSpace(d.Values["apify_api_key"])
	actorID := a.Cfg.Apify.Actors.ActiveListings
	if apiKey == "" {
		apiKey = a.Cfg.Apify.APIKey
	}
	if apiKey == "" || actorID == "" {
		d.TestApifyOK = "Apify API key or active_listings actor is not configured."
		render(w, r, templates.Settings(d))
		return
	}
	client := apify.New(apiKey)
	var proxy *apify.ProxyConfiguration
	p := a.Cfg.Apify.Proxy
	if p.UseApifyProxy {
		proxy = &apify.ProxyConfiguration{
			UseApifyProxy:     true,
			ApifyProxyGroups:  p.Groups,
			ApifyProxyCountry: p.Country,
		}
	}
	raw, err := client.Run(r.Context(), actorID, apify.ActiveListingInput{
		SearchQueries:        []string{"test"},
		MaxProductsPerSearch: 1,
		MaxSearchPages:       1,
		ListingType:          "all",
		ProxyConfiguration:   proxy,
	})
	if err != nil {
		d.TestApifyOK = "Apify test failed: " + err.Error()
	} else {
		// The test launches a real, billed actor run; count it toward the
		// budget view like every other Apify run.
		if incErr := a.Store.IncrementApifyUsage(r.Context()); incErr != nil {
			slog.Error("apify usage increment failed", "err", incErr)
		}
		d.TestApifyOK = fmt.Sprintf("Apify returned %d item(s).", len(raw))
	}
	render(w, r, templates.Settings(d))
}

func (a *App) PostTestEbay(w http.ResponseWriter, r *http.Request) {
	cur := auth.CurrentUserFromRequest(r)
	if cur == nil || cur.Role != models.RoleAdmin {
		http.Error(w, "forbidden", http.StatusForbidden)
		return
	}
	d, err := a.settingsData(r)
	if err != nil {
		a.serverError(w, r, err)
		return
	}
	// Settings-table values win over config.toml. Both paths are trimmed:
	// a stray newline in the TOML would otherwise reach eBay verbatim.
	clientID := strings.TrimSpace(d.Values["ebay_client_id"])
	if clientID == "" {
		clientID = strings.TrimSpace(a.Cfg.Ebay.ClientID)
	}
	clientSecret := strings.TrimSpace(d.Values["ebay_client_secret"])
	if clientSecret == "" {
		clientSecret = strings.TrimSpace(a.Cfg.Ebay.ClientSecret)
	}
	if clientID == "" || clientSecret == "" {
		d.TestEbayOK = "Set the eBay App ID and Cert ID first."
		render(w, r, templates.Settings(d))
		return
	}
	if d.EbayDailyLimit > 0 && d.EbayUsedToday >= d.EbayDailyLimit {
		d.TestEbayOK = fmt.Sprintf("Daily eBay API call limit reached (%d/%d). Test skipped.", d.EbayUsedToday, d.EbayDailyLimit)
		render(w, r, templates.Settings(d))
		return
	}

	env := "production"
	if strings.EqualFold(strings.TrimSpace(a.Cfg.Ebay.Environment), "sandbox") {
		env = "sandbox"
	}
	// Echo back exactly what was sent (App ID masked, Cert ID length only) so
	// a failure points at the inputs, not just "it failed".
	inputs := fmt.Sprintf("%s, App ID %s, Cert ID %d chars", env, maskID(clientID), len(clientSecret))

	client := ebay.New(clientID, clientSecret, a.Cfg.Ebay.Environment)
	listings, err := client.Search(r.Context(), ebay.SearchParams{
		MarketplaceID: "EBAY_US",
		Query:         "test",
		Limit:         1,
	})
	// A real call was made; count it against the daily allowance.
	if n, incErr := a.Store.IncrementEbayUsage(r.Context()); incErr == nil {
		d.EbayUsedToday = n
	}
	if err != nil {
		msg := fmt.Sprintf("eBay test failed (%s): %s", inputs, err.Error())
		if ks := ebayKeysetEnv(clientID); ks != "" && ks != env {
			msg += fmt.Sprintf(" — the App ID looks like a %s keyset, but environment is %q. Set environment = %q in the [ebay] config block (or use your %s keyset).", ks, env, ks, env)
		}
		d.TestEbayOK = msg
	} else {
		d.TestEbayOK = fmt.Sprintf("eBay Browse API reachable (%s). Returned %d item(s).", inputs, len(listings))
	}
	render(w, r, templates.Settings(d))
}

// maskID returns a fingerprint of a credential for display: enough of the head
// to recognize it, the rest elided. Used only for the App ID (the non-secret
// half of the OAuth pair) — never for the Cert ID.
func maskID(s string) string {
	if len(s) <= 12 {
		return strings.Repeat("•", len(s))
	}
	return s[:12] + "…(" + strconv.Itoa(len(s)) + " chars)"
}

// ebayKeysetEnv guesses which environment an eBay App ID belongs to from the
// SBX/PRD marker eBay embeds in it (e.g. "Name-app-PRD-1a2b..."). Returns ""
// when no marker is present.
func ebayKeysetEnv(clientID string) string {
	up := strings.ToUpper(clientID)
	switch {
	case strings.Contains(up, "-SBX-"):
		return "sandbox"
	case strings.Contains(up, "-PRD-"):
		return "production"
	default:
		return ""
	}
}