// SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Commercial
// SPDX-FileCopyrightText: 2025-2026 Christian Galo

package server

import (
	"context"
	"html/template"
	"log/slog"

	"git.coopcloud.tech/wiki-cafe/member-console/internal/web"
)

// The rule-less warning (design.md A8, M1): one sentence, identical on the
// five surfaces that hand a rank-0 product to a population or grant one, with
// the set's name linked to the set's page so the operator can add a rule
// without losing the preview. It is a warning and nothing more: every commit
// stays enabled and no control renders disabled.
//
// The condition is read from core.product_shape's active_rule_count, which is
// the sole source of the answer to whether a product's set provides anything
// (product-catalog; design.md M8, Decision 148). Nothing here counts
// entitlement_set_rules.

// ruleLessWarning returns the sentence for productID, or "" when the product
// carries a set with at least one active rule, carries no set at all, or
// cannot be read. A read failure is silent by design: the sentence is a
// warning, and a failed read must not invent one or block the preview.
func (h *OperatorPartialsHandler) ruleLessWarning(ctx context.Context, productID string) template.HTML {
	if productID == "" || h.BillingQ == nil || h.EntitlementsQ == nil {
		return ""
	}
	shape, err := h.BillingQ.GetProductShape(ctx, productID)
	if err != nil {
		h.Logger.Error("failed to read product shape for the rule-less warning",
			slog.Any("error", err), slog.String("product_id", productID))
		return ""
	}
	if shape.ActiveRuleCount > 0 {
		return ""
	}
	product, err := h.BillingQ.GetProductByID(ctx, productID)
	if err != nil {
		h.Logger.Error("failed to read the product for the rule-less warning",
			slog.Any("error", err), slog.String("product_id", productID))
		return ""
	}
	// No set at all is a different fact, reported by the readiness surfaces'
	// entitlement-set row; this sentence names a set.
	if !product.EntitlementSetID.Valid {
		return ""
	}
	setID := product.EntitlementSetID.UUID.String()
	set, err := h.EntitlementsQ.GetEntitlementSetByID(ctx, setID)
	if err != nil {
		h.Logger.Error("failed to read the entitlement set for the rule-less warning",
			slog.Any("error", err), slog.String("set_id", setID))
		return ""
	}
	return ruleLessWarningSentence(product.Name, setID, set.Name)
}

// ruleLessWarningSentence is the one wording, in one place, so the five
// surfaces cannot drift apart.
func ruleLessWarningSentence(productName, setID, setName string) template.HTML {
	setURL, err := web.RouteURL("/operator/entitlement-sets/{setID}", setID)
	if err != nil {
		setURL = "/operator/entitlement-sets"
	}
	return template.HTML(template.HTMLEscapeString(productName) +
		` provides nothing: its entitlement set <a href="` +
		template.HTMLEscapeString(setURL) + `">` + template.HTMLEscapeString(setName) +
		`</a> has no active rule.`)
}