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

// Package usage converges the `fedwiki_sites` reservation counter on the
// site rows FedWiki owns (design D2 of slice3-walk-fixes).
//
// It sits below both callers -- the web handlers and the Temporal activities,
// which cannot import each other -- and below the integration root, which runs
// the boot repair.
package usage

import (
	"context"
	"database/sql"
	"errors"

	"git.coopcloud.tech/wiki-cafe/member-console/internal/entitlements"
	fwmod "git.coopcloud.tech/wiki-cafe/member-console/internal/integrations/fedwiki/store"
)

// ResourceKey is the entitlements resource key sites are counted under.
const ResourceKey = "fedwiki_sites"

// ActiveSites counts a workspace's active site rows: the display truth for
// every quota surface (design D1).
func ActiveSites(ctx context.Context, siteQ fwmod.Querier, workspaceID string) (int64, error) {
	return siteQ.CountActiveSitesByWorkspace(ctx, workspaceID)
}

// ReconcileWorkspace raises the workspace's counter to its active site row
// count, never lowering it: between a create workflow's gated increment and
// its row insert the counter legitimately exceeds the rows, and lowering there
// would erase that reservation. Real deletions are lowered by the decrement
// and status-drift paths, and by the exact set at boot.
//
// Returns the observed active row count. A workspace with no primary pool
// assignment has no counter to converge on and is not an error.
func ReconcileWorkspace(ctx context.Context, entQ entitlements.Querier, siteQ fwmod.Querier, workspaceID string) (int64, error) {
	observed, poolID, err := observe(ctx, entQ, siteQ, workspaceID)
	if err != nil || poolID == "" {
		return observed, err
	}
	_, err = entQ.RaiseNumericUsageTo(ctx, entitlements.RaiseNumericUsageToParams{
		PoolID:      poolID,
		ResourceKey: ResourceKey,
		Observed:    observed,
	})
	return observed, err
}

// SetWorkspaceExact sets the workspace's counter to its active site row count,
// for boot reconciliation only: no create workflow holds an unmaterialized
// reservation then, so the rows are the whole truth and an overstated counter
// (which refuses creates) comes back down.
//
// Reports whether a counter row was updated; a workspace whose pool has no
// usage row for the key has nothing to repair (the materializer creates the
// row when the entitlement is materialized).
func SetWorkspaceExact(ctx context.Context, entQ entitlements.Querier, siteQ fwmod.Querier, workspaceID string) (observed int64, updated bool, err error) {
	observed, poolID, err := observe(ctx, entQ, siteQ, workspaceID)
	if err != nil || poolID == "" {
		return observed, false, err
	}
	res, err := entQ.SetNumericUsage(ctx, entitlements.SetNumericUsageParams{
		PoolID:      poolID,
		ResourceKey: ResourceKey,
		Observed:    observed,
	})
	if err != nil {
		return observed, false, err
	}
	rows, err := res.RowsAffected()
	if err != nil {
		return observed, false, err
	}
	return observed, rows > 0, nil
}

// observe resolves the workspace's primary pool (the resolution every quota
// read uses) and counts its active site rows. An absent assignment yields an
// empty pool id rather than an error: nothing to reconcile.
func observe(ctx context.Context, entQ entitlements.Querier, siteQ fwmod.Querier, workspaceID string) (int64, string, error) {
	assignment, err := entQ.GetPrimaryPoolAssignmentByWorkspace(ctx, workspaceID)
	if errors.Is(err, sql.ErrNoRows) {
		return 0, "", nil
	}
	if err != nil {
		return 0, "", err
	}
	observed, err := siteQ.CountActiveSitesByWorkspace(ctx, workspaceID)
	if err != nil {
		return 0, "", err
	}
	return observed, assignment.PoolID, nil
}