// Copyright (C) 2026 Dcntrlized
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published
// by the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

package containers

import (
	"context"
	"fmt"
	"strings"

	"git.dcntrlized.org/Dcntrlized/Maestro/lib/docker"
	"git.dcntrlized.org/Dcntrlized/Maestro/lib/logger"
	libregistry "git.dcntrlized.org/Dcntrlized/Maestro/lib/registry"
	"git.dcntrlized.org/Dcntrlized/Maestro/lib/types"
	"github.com/docker/docker/api/types/container"
	"github.com/docker/docker/api/types/filters"
	"github.com/docker/docker/api/types/network"
)

const (
	// DCNTRLIZEDNetwork is the external Docker network every dcntrlized service joins.
	DCNTRLIZEDNetwork = "dcntrlized_net"
	// DatabaseServiceName is the shared database service (image, container and DNS name).
	DatabaseServiceName = "dcntrlized-db"
	// AuthServiceName is the shared auth service (image, container and DNS name).
	AuthServiceName = "dcntrlized-auth"
)

// EnsureDCNTRLIZEDNetwork creates the external dcntrlized_net network when it is
// missing. Every service compose file declares it as external, so it must exist
// before any compose project is started.
func EnsureDCNTRLIZEDNetwork(ctx context.Context, dc *docker.DockerClient) error {
	if _, err := dc.NetworkInspect(ctx, DCNTRLIZEDNetwork, network.InspectOptions{}); err == nil {
		return nil
	}
	if _, err := dc.NetworkCreate(ctx, DCNTRLIZEDNetwork, network.CreateOptions{}); err != nil {
		return fmt.Errorf("failed to create network %s: %w", DCNTRLIZEDNetwork, err)
	}
	logger.Info("Created external Docker network %s", DCNTRLIZEDNetwork)
	return nil
}

// EnsureDatabaseRunning ensures the shared database container is running. On a
// fresh host — when the database is not installed yet — it resolves the
// database from the registry and installs it automatically before starting it.
// The database is infrastructure, so this must never be invoked for the
// database service itself (StartContainer guards that).
func EnsureDatabaseRunning(ctx context.Context) error {
	return ensureInfraRunning(ctx, DatabaseServiceName, "shared database")
}

// EnsureAuthRunning ensures the shared auth service container is running. The
// auth service is hidden infrastructure: every consumer proxies /auth/* to it
// and validates action tokens with its key, so it must be up before services
// that depend on it start. Like the database, it is installed automatically
// from the registry when it is missing.
func EnsureAuthRunning(ctx context.Context) error {
	return ensureInfraRunning(ctx, AuthServiceName, "shared auth service")
}

// ensureInfraRunning makes sure a hidden infrastructure container (shared
// database, shared auth service) is running. When the service is not installed
// yet it resolves the registry item and installs it first, so a fresh host
// boots with its infrastructure without manual UI steps. Failures are returned
// to the caller, which treats them as non-fatal warnings.
func ensureInfraRunning(ctx context.Context, serviceName, label string) error {
	dc, err := docker.NewDockerClient()
	if err != nil {
		return fmt.Errorf("failed to initialize docker client: %w", err)
	}
	defer dc.Close()

	if err := EnsureDCNTRLIZEDNetwork(ctx, dc); err != nil {
		return err
	}

	if infraRunning(ctx, dc, serviceName) {
		return nil
	}
	if !IsInstalled(serviceName) {
		logger.Info("%s %s not installed; installing from the registry...", label, serviceName)
		item, err := libregistry.ItemByName(ctx, serviceName)
		if err != nil {
			return fmt.Errorf("failed to resolve %s %s from the registry: %w", label, serviceName, err)
		}
		if err := InstallContainer(ctx, *item); err != nil {
			return fmt.Errorf("failed to install %s %s: %w", label, serviceName, err)
		}
	}

	logger.Info("Starting %s %s...", label, serviceName)
	if err := StartContainer(ctx, types.RegistryContainer{Name: serviceName}); err != nil {
		return fmt.Errorf("failed to start %s %s: %w", label, serviceName, err)
	}
	return nil
}

// infraRunning reports whether the named infrastructure container is currently up.
func infraRunning(ctx context.Context, dc *docker.DockerClient, serviceName string) bool {
	filter := filters.NewArgs()
	filter.Add("label", "org.dcntrlized.service="+serviceName)

	containers, err := dc.ContainerList(ctx, container.ListOptions{All: true, Filters: filter})
	if err != nil {
		logger.Warn("Failed to list %s containers: %v", serviceName, err)
		return false
	}
	for _, c := range containers {
		if c.State != "running" && c.State != "restarting" {
			continue
		}
		// Only the canonical container (e.g. "dcntrlized-auth") counts as the
		// shared infrastructure being up. Dev lookalikes (auth-debug) share the
		// role label but must never satisfy the check.
		for _, n := range c.Names {
			if strings.TrimPrefix(n, "/") == serviceName {
				return true
			}
		}
	}
	return false
}