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

package server

import (
	"context"
	"log/slog"
	"strings"

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

// The entitlement-set forms (spec entitlement-set-management "Operator
// entitlement set creation", "Operator entitlement set editing", "Operator
// entitlement set rule management", "The Rules table is the rule form";
// spec form-library; design D1, D2, D7, D8 of staged-rule-changes). Two
// declarations: the set itself (create page and the composite's edit form,
// one declaration in two modes) and the Rules table, one batch form of the
// rows family whose editing rows carry the declaration's controls in the
// table's own columns.
//
// This file is the two forms' home; the registry is only the index
// (design D1). It sits beside operator_entitlement_sets.go, which parses
// through both declarations and never through r.FormValue.

const entitlementSetFormName = "operator.entitlement-set"

// entitlementSetForm is registered at package init, so the registry is
// complete for the invariants test, the route test and the
// registered-forms table whether or not a handler has been built (the
// same choice lane A made for operator.product).
var entitlementSetForm = forms.Register(forms.FormSpec{
	Name:   entitlementSetFormName,
	Kind:   forms.KindCreate,
	Family: forms.Stacked,
	Method: "POST",
	Path:   "/partials/operator/entitlement-sets",
	// The record side is a different route: the create page posts to the
	// collection, the edit form puts to the record.
	EditMethod: "PUT",
	EditPath:   "/partials/operator/entitlement-sets/{setID}",
	// Both sides re-render the operator body: saving a set changes its
	// rules section as well as the form, and a refusal must swap into the
	// same target the success does (design D9, lesson L§17).
	Target: "#operator-body",
	Swap:   "innerHTML",
	Fields: []forms.Field{
		forms.RecordName(),
		forms.RecordDescription(),
		entitlementSetActiveField(),
	},
	Commit:     "Create entitlement set",
	CommitEdit: "Save changes",
	WayOut:     forms.LinkOut("Cancel", "/operator/entitlement-sets"),
})

// entitlementSetActiveField is the set's Active state, edit-only because a
// set is created active (finding FA-3). Unlike the product's edit-only
// fields, this one carries a Notice: entitlement-set-management's own
// scenario asks that the edit form say, at the field, why Active appears
// only there, since "why is there no toggle on the create page" is a
// question an operator would otherwise have to guess at (a set is always
// created active by design D21, and deactivating one is how a set that
// products or pools still reference gets retired without being deleted).
func entitlementSetActiveField() forms.Field {
	f := forms.Field{
		Name:    "is_active",
		Label:   "Active",
		Control: forms.Checkbox,
		Value:   "true",
		Help:    forms.Help("Active", "Inactive sets stay with the products that use them but cannot be chosen for a product."),
		Notice:  "A set is created active; deactivating here retires a set that products or pools still reference.",
	}
	return f.On(forms.EditOnly)
}

// entitlementSetCreateForm renders the create page's form: unbound on a
// first visit, submission-bound on a refusal.
func entitlementSetCreateForm(values forms.Values, errs *forms.Errors) forms.FormView {
	mode := forms.ModeUnbound
	if errs.Any() {
		mode = forms.ModeSubmission
	}
	return forms.Render(entitlementSetForm, forms.Binding{
		Mode:   mode,
		Side:   forms.CreateOnly,
		Values: values,
		Errors: errs,
	})
}

// entitlementSetEditForm renders the composite's Details section, bound to
// the set or to a refused submission of it.
func entitlementSetEditForm(setID string, values forms.Values, errs *forms.Errors) forms.FormView {
	mode := forms.ModeRecord
	if errs.Any() {
		mode = forms.ModeSubmission
	}
	action, err := web.RouteURL(entitlementSetForm.EditPath, setID)
	if err != nil {
		action = entitlementSetForm.Path
	}
	return forms.Render(entitlementSetForm, forms.Binding{
		Mode:   mode,
		Side:   forms.EditOnly,
		Action: action,
		Values: values,
		Errors: errs,
	})
}

// entitlementSetEditValues binds a set record to the declaration's fields.
func entitlementSetEditValues(v EntitlementSetViewModel) forms.Values {
	values := forms.NewValues()
	values.Set("name", v.Name)
	values.Set("description", v.Description)
	if f, ok := entitlementSetForm.Field("is_active"); ok {
		values.SetBool(f, v.IsActive)
	}
	return values
}

// The rules form. One declaration, operator.entitlement-set.rules, of the
// batch kind in the rows family (design D1 of staged-rule-changes): the
// Rules table is the form's body, its editing rows carry the declaration's
// controls in the table's own columns, and the staged batch rides in one
// tray under the table. The Limit and "Per unit" fields declare a ShowIf
// condition on resourceKeyKind, a Hidden marker the handler fills from the
// selected key's database-derived kind, never from user choice, so the
// fields a key reveals are the declaration's own render
// (entitlement-set-management "the kind-dependent fields SHALL NOT be
// swapped in by a hand-built partial").

const (
	entitlementSetRulesFormName = "operator.entitlement-set.rules"
	// entitlementSetRulesRoute is where every row action, Undo and Discard
	// all post; entitlementSetRulesApplyRoute is the commit's own path
	// (design D2: a row action re-renders the section, the commit applies
	// the batch and re-renders the body).
	entitlementSetRulesRoute      = "/partials/operator/entitlement-sets/{setID}/rules"
	entitlementSetRulesApplyRoute = "/partials/operator/entitlement-sets/{setID}/rules/apply"
	// entitlementSetRulesTarget is the section every row action swaps.
	entitlementSetRulesTarget = "#entitlement-set-rules"
	// entitlementSetRulesNewRow is the instance of the one editing row that
	// belongs to no stored rule: the add form Add rule opens above the table.
	entitlementSetRulesNewRow     = "new"
	entitlementSetRuleNumericKind = "numeric"
	// entitlementSetRuleAddKeyPrefix names a delta that adds a rule the set
	// does not have yet, whose key cannot be a rule id.
	entitlementSetRuleAddKeyPrefix = "new:"
)

var entitlementSetRulesForm = forms.Register(forms.FormSpec{
	Name:         entitlementSetRulesFormName,
	Kind:         forms.KindBatch,
	Family:       forms.Rows,
	Method:       "POST",
	Path:         entitlementSetRulesRoute,
	CommitAction: entitlementSetRulesApplyRoute,
	// A row action re-renders the Rules section whole, from the submitted
	// state, so two open editors and a staged change survive every press
	// (design D2). The commit carries its own target, the operator body.
	Target: entitlementSetRulesTarget,
	Swap:   "outerHTML",
	Fields: []forms.Field{
		entitlementSetRuleKeyField(),
		entitlementSetRuleKindField(),
		entitlementSetRuleValueField(),
		entitlementSetRulePerUnitField(),
		entitlementSetRulePolicyField(),
		entitlementSetRuleNoteField(),
	},
	Commit: "Apply changes",
	WayOut: forms.WayOut{Label: "Discard all"},
})

// The three verbs a delta carries.
const (
	entitlementSetRuleVerbAdd    = "add"
	entitlementSetRuleVerbEdit   = "edit"
	entitlementSetRuleVerbRemove = "remove"
)

// The acts a row action posts. An empty act is the plain re-render the add
// form's resource-key select fires on change: the handler re-reads the whole
// submitted state and renders it back, which is how choosing a key reveals
// that kind's fields beside the select.
const (
	entitlementSetRuleActAdd     = "add"
	entitlementSetRuleActEdit    = "edit"
	entitlementSetRuleActCancel  = "cancel"
	entitlementSetRuleActStage   = "stage"
	entitlementSetRuleActRemove  = "remove"
	entitlementSetRuleActUndo    = "undo"
	entitlementSetRuleActDiscard = "discard"
)

// entitlementSetRuleKeyField is the key-first picker, the add form's first
// field: choosing a key derives the rule's shape (entitlement-set-management
// "The form SHALL NOT expose a rule-type selector"). Its on-change swap posts
// the whole form and re-renders the section, so the kind-dependent fields
// appear beside the select that is already open and nothing typed elsewhere
// is lost. The concrete path is filled in per render
// (entitlementSetRulesSpecFor), because Field.Attrs is fixed at declaration
// time and cannot embed the set's id. One rung narrower than a select's
// natural third, so the add form's five columns and its two buttons fit one
// dense row at the laptop width; the table's cells ignore the width.
func entitlementSetRuleKeyField() forms.Field {
	return forms.Field{
		Name:           "resource_key",
		Label:          "Resource",
		Control:        forms.Select,
		RuntimeOptions: true,
		Width:          forms.WidthNarrower,
	}
}

// entitlementSetRuleKindField is the ShowIf marker: the selected key's kind,
// resolved server-side from the database on every request, never read back
// for the write itself (the rule's type is derived fresh at the commit;
// entitlement-set-management "Rule type cannot be chosen by the client").
func entitlementSetRuleKindField() forms.Field {
	return forms.Field{Name: "resource_key_kind", Label: "Resource key kind", Control: forms.Hidden, Optional: true}
}

// entitlementSetRuleValueField is the Limit control of an editing row, in
// the table's own Limit column. No hint: the column header labels it at
// desktop width and its own label does below lg.
func entitlementSetRuleValueField() forms.Field {
	return forms.Field{
		Name:    "resource_value",
		Label:   "Limit",
		Control: forms.Number,
		Min:     "0",
		ShowIf:  forms.ShowIf{Field: "resource_key_kind", Equals: []string{entitlementSetRuleNumericKind}},
	}
}

// entitlementSetRulePerUnitField is the Per unit control, in the Per unit
// column. It carries no hint and no help icon of its own: the column
// header's help icon states what the flag does.
func entitlementSetRulePerUnitField() forms.Field {
	return forms.Field{
		Name:    "resource_per_unit",
		Label:   "Per unit",
		Control: forms.Checkbox,
		Value:   "true",
		ShowIf:  forms.ShowIf{Field: "resource_key_kind", Equals: []string{entitlementSetRuleNumericKind}},
	}
}

// entitlementSetRulePolicyField is the reduction policy, a field of the rule
// edited beside its limit in the Rules table's own column (design D7; the
// maintainer's decision 1 of 2026-09-19 moved it out of the tray). Its
// options are per row, because a rule whose stored value is dormant offers
// that value as its own option; a boolean row carries no policy control at
// all, because no reduction policy acts on a rule that grants or withholds a
// capability. One rung narrower in the add form's dense row, as the key
// select is, for the same reason.
func entitlementSetRulePolicyField() forms.Field {
	return forms.Field{
		Name:           "tier_reduction_policy",
		Label:          "Reduction policy",
		Control:        forms.Select,
		RuntimeOptions: true,
		Width:          forms.WidthNarrower,
		ShowIf:         forms.ShowIf{Field: "resource_key_kind", Equals: []string{entitlementSetRuleNumericKind}},
	}
}

// entitlementSetRuleNoteField is the batch's own field, rendered once in the
// tray before the commit.
func entitlementSetRuleNoteField() forms.Field {
	return forms.Field{
		Name:      "note",
		Label:     "Note",
		Control:   forms.Text,
		Optional:  true,
		MaxLen:    500,
		Placement: forms.PlaceTray,
	}
}

// The reduction policy's four stored values. Only clamp and force_reduce act
// at a rule commit, so only those two are offered on a new staging; block and
// defer are offered back to the rule that already carries one, selected, so
// the console rewrites a stored promise only when the operator picks another
// (design D7).
const (
	entitlementSetRulePolicyClamp       = "clamp"
	entitlementSetRulePolicyForceReduce = "force_reduce"
	entitlementSetRulePolicyBlock       = "block"
	entitlementSetRulePolicyDefer       = "defer"
)

// entitlementSetRulePolicyDefault is where a new rule's select opens: the
// console writes an acting value while the column default stays the model's.
const entitlementSetRulePolicyDefault = entitlementSetRulePolicyClamp

// entitlementSetRulePolicyOptions are one row's options: the two acting
// values, plus the stored value when it is one of the dormant two.
func entitlementSetRulePolicyOptions(stored string) []forms.Option {
	out := []forms.Option{
		{Value: entitlementSetRulePolicyClamp, Label: "Clamp"},
		{Value: entitlementSetRulePolicyForceReduce, Label: "Force reduce"},
	}
	switch stored {
	case entitlementSetRulePolicyBlock:
		out = append(out, forms.Option{Value: entitlementSetRulePolicyBlock, Label: "Block"})
	case entitlementSetRulePolicyDefer:
		out = append(out, forms.Option{Value: entitlementSetRulePolicyDefer, Label: "Defer"})
	}
	return out
}

// entitlementSetRulePolicyAccepted is what ParseBatchWith checks a submitted
// policy against: every value the page can render anywhere. Which of them one
// delta may actually carry is checked per delta against its own options,
// because a crafted submission can name a value no line offered.
func entitlementSetRulePolicyAccepted() []forms.Option {
	return []forms.Option{
		{Value: entitlementSetRulePolicyClamp, Label: "Clamp"},
		{Value: entitlementSetRulePolicyForceReduce, Label: "Force reduce"},
		{Value: entitlementSetRulePolicyBlock, Label: "Block"},
		{Value: entitlementSetRulePolicyDefer, Label: "Defer"},
	}
}

// entitlementSetRulePolicyOffered reports whether policy is one of the
// options a row whose stored value is stored would have offered.
func entitlementSetRulePolicyOffered(stored, policy string) bool {
	for _, o := range entitlementSetRulePolicyOptions(stored) {
		if o.Value == policy {
			return true
		}
	}
	return false
}

// entitlementSetRulePolicyLabel is a policy value as its select labels it
// ("Clamp", "Force reduce", "Block", "Defer"), which is how the table states
// it at rest; an unknown value reads as itself.
func entitlementSetRulePolicyLabel(value string) string {
	for _, o := range entitlementSetRulePolicyAccepted() {
		if o.Value == value {
			return o.Label
		}
	}
	return value
}

// entitlementSetRulePolicyWord is the same label lowered for a sentence
// ("reduction policy clamp becomes force reduce").
func entitlementSetRulePolicyWord(value string) string {
	return strings.ToLower(entitlementSetRulePolicyLabel(value))
}

// entitlementSetRulesSpecFor is the declaration with the resource-key
// select's escape-hatch Attrs filled in for one set: it fires a scoped POST to
// the row-action route on change, carrying the whole form and swapping the
// Rules section back, so choosing a key reveals that row's numeric fields and
// puts the row under its kind's group. The registered declaration carries no
// Attrs, because a set's route cannot be known until it renders; Parse never
// reads Attrs, so the registered value is enough for parsing (the org-type
// card's per-render copy is the precedent).
func entitlementSetRulesSpecFor(setID string) forms.FormSpec {
	spec := entitlementSetRulesForm
	action, err := web.RouteURL(entitlementSetRulesRoute, setID)
	if err != nil {
		action = entitlementSetRulesRoute
	}
	swap := map[string]string{
		"hx-post":    action,
		"hx-trigger": "change",
		"hx-sync":    "this:replace",
		"hx-include": "closest form",
		"hx-target":  entitlementSetRulesTarget,
		"hx-swap":    "outerHTML",
	}
	fields := make([]forms.Field, 0, len(spec.Fields))
	for _, f := range spec.Fields {
		if f.Name == "resource_key" {
			f.Attrs = swap
		}
		fields = append(fields, f)
	}
	spec.Fields = fields
	return spec
}

// entitlementSetRulesAction is the concrete row-action path for one set, and
// entitlementSetRulesApplyAction the commit's.
func entitlementSetRulesAction(setID string) string {
	action, err := web.RouteURL(entitlementSetRulesRoute, setID)
	if err != nil {
		return entitlementSetRulesRoute
	}
	return action
}

func entitlementSetRulesApplyAction(setID string) string {
	action, err := web.RouteURL(entitlementSetRulesApplyRoute, setID)
	if err != nil {
		return entitlementSetRulesApplyRoute
	}
	return action
}

// entitlementSetRuleKeyOptions builds the resource-key select's options: a
// "Choose a resource key" placeholder (spec form-conventions "A select that
// needs a choice opens with a placeholder option") followed by every key
// still available for a new rule on this set (finding #21: a key that already
// has an active rule on this set is excluded, since offering it could only
// 422).
func entitlementSetRuleKeyOptions(keys []ResourceKeyOption) []forms.Option {
	out := make([]forms.Option, 0, len(keys)+1)
	out = append(out, forms.ChooseOption("a resource key"))
	for _, k := range keys {
		out = append(out, forms.Option{Value: k.ResourceKey, Label: k.DisplayName + " (" + k.ResourceKey + ")"})
	}
	return out
}

// entitlementSetRulesParseOptions is the option set ParseBatchWith reads a
// request through: every key the page could have offered, and every policy
// value any row could have offered.
func entitlementSetRulesParseOptions(keys []ResourceKeyOption) map[string][]forms.Option {
	return map[string][]forms.Option{
		"resource_key":          entitlementSetRuleKeyOptions(keys),
		"tier_reduction_policy": entitlementSetRulePolicyAccepted(),
	}
}

// entitlementSetAvailableRuleKeys lists the resource keys usable for a new
// rule on setID: the catalog minus any key that already has an active rule on
// this set.
func (h *OperatorPartialsHandler) entitlementSetAvailableRuleKeys(ctx context.Context, setID string) []ResourceKeyOption {
	ruled := map[string]bool{}
	if rules, err := h.EntitlementsQ.GetActiveRulesBySetID(ctx, setID); err != nil {
		h.Logger.Error("failed to list rules for key availability", slog.Any("error", err))
	} else {
		for _, rule := range rules {
			if rule.ResourceKey.Valid {
				ruled[rule.ResourceKey.String] = true
			}
		}
	}
	keys, err := h.EntitlementsQ.ListResourceKeys(ctx)
	if err != nil {
		h.Logger.Error("failed to list resource keys", slog.Any("error", err))
		return nil
	}
	out := make([]ResourceKeyOption, 0, len(keys))
	for _, rk := range keys {
		if ruled[rk.ResourceKey] {
			continue
		}
		out = append(out, ResourceKeyOption{ResourceKey: rk.ResourceKey, DisplayName: rk.DisplayName})
	}
	return out
}