// Copyright 2025 Cloudbase Solutions SRL
//
//	Licensed under the Apache License, Version 2.0 (the "License"); you may
//	not use this file except in compliance with the License. You may obtain
//	a copy of the License at
//
//	     http://www.apache.org/licenses/LICENSE-2.0
//
//	Unless required by applicable law or agreed to in writing, software
//	distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
//	WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
//	License for the specific language governing permissions and limitations
//	under the License.
package entity

import (
	"context"
	"fmt"
	"log/slog"
	"sync"

	"golang.org/x/sync/errgroup"

	"github.com/cloudbase/garm/auth"
	dbCommon "github.com/cloudbase/garm/database/common"
	"github.com/cloudbase/garm/database/watcher"
	"github.com/cloudbase/garm/params"
	"github.com/cloudbase/garm/runner/common"
	garmUtil "github.com/cloudbase/garm/util"
)

func NewController(ctx context.Context, store dbCommon.Store, providers map[string]common.Provider) (*Controller, error) {
	consumerID := "entity-controller"
	ctx = garmUtil.WithSlogContext(
		ctx,
		slog.Any("worker", consumerID))
	ctx = auth.GetAdminContext(ctx)

	return &Controller{
		consumerID: consumerID,
		ctx:        ctx,
		store:      store,
		providers:  providers,
		Entities:   make(map[string]*Worker),
	}, nil
}

type Controller struct {
	consumerID string
	ctx        context.Context

	consumer dbCommon.Consumer
	store    dbCommon.Store

	providers map[string]common.Provider
	Entities  map[string]*Worker

	running bool
	quit    chan struct{}

	mux sync.Mutex
}

func (c *Controller) loadAllRepositories() error {
	c.mux.Lock()
	defer c.mux.Unlock()
	repos, err := c.store.ListRepositories(c.ctx, params.RepositoryFilter{})
	if err != nil {
		return fmt.Errorf("fetching repositories: %w", err)
	}

	g, _ := errgroup.WithContext(c.ctx)
	for _, repo := range repos {
		g.Go(func() error {
			entity, err := repo.GetEntity()
			if err != nil {
				return fmt.Errorf("getting entity: %w", err)
			}
			worker, err := NewWorker(c.ctx, c.store, entity, c.providers)
			if err != nil {
				return fmt.Errorf("creating worker: %w", err)
			}
			if err := worker.Start(); err != nil {
				return fmt.Errorf("starting worker: %w", err)
			}
			c.Entities[entity.ID] = worker
			return nil
		})
	}
	if err := c.waitForErrorGroupOrContextCancelled(g); err != nil {
		return fmt.Errorf("waiting for error group: %w", err)
	}
	return nil
}

func (c *Controller) loadAllOrganizations() error {
	c.mux.Lock()
	defer c.mux.Unlock()
	orgs, err := c.store.ListOrganizations(c.ctx, params.OrganizationFilter{})
	if err != nil {
		return fmt.Errorf("fetching organizations: %w", err)
	}

	g, _ := errgroup.WithContext(c.ctx)
	for _, org := range orgs {
		g.Go(func() error {
			entity, err := org.GetEntity()
			if err != nil {
				return fmt.Errorf("getting entity: %w", err)
			}
			worker, err := NewWorker(c.ctx, c.store, entity, c.providers)
			if err != nil {
				return fmt.Errorf("creating worker: %w", err)
			}
			if err := worker.Start(); err != nil {
				return fmt.Errorf("starting worker: %w", err)
			}
			c.Entities[entity.ID] = worker
			return nil
		})
	}
	if err := c.waitForErrorGroupOrContextCancelled(g); err != nil {
		return fmt.Errorf("waiting for error group: %w", err)
	}
	return nil
}

func (c *Controller) loadAllEnterprises() error {
	c.mux.Lock()
	defer c.mux.Unlock()
	enterprises, err := c.store.ListEnterprises(c.ctx, params.EnterpriseFilter{})
	if err != nil {
		return fmt.Errorf("fetching enterprises: %w", err)
	}

	g, _ := errgroup.WithContext(c.ctx)

	for _, enterprise := range enterprises {
		g.Go(func() error {
			entity, err := enterprise.GetEntity()
			if err != nil {
				return fmt.Errorf("getting entity: %w", err)
			}
			worker, err := NewWorker(c.ctx, c.store, entity, c.providers)
			if err != nil {
				return fmt.Errorf("creating worker: %w", err)
			}
			if err := worker.Start(); err != nil {
				return fmt.Errorf("starting worker: %w", err)
			}
			c.Entities[entity.ID] = worker
			return nil
		})
	}
	if err := c.waitForErrorGroupOrContextCancelled(g); err != nil {
		return fmt.Errorf("waiting for error group: %w", err)
	}
	return nil
}

func (c *Controller) Start() error {
	c.mux.Lock()
	if c.running {
		c.mux.Unlock()
		return nil
	}
	c.mux.Unlock()

	g, _ := errgroup.WithContext(c.ctx)
	g.Go(func() error {
		if err := c.loadAllEnterprises(); err != nil {
			return fmt.Errorf("loading enterprises: %w", err)
		}
		return nil
	})

	g.Go(func() error {
		if err := c.loadAllOrganizations(); err != nil {
			return fmt.Errorf("loading organizations: %w", err)
		}
		return nil
	})

	g.Go(func() error {
		if err := c.loadAllRepositories(); err != nil {
			return fmt.Errorf("loading repositories: %w", err)
		}
		return nil
	})

	if err := c.waitForErrorGroupOrContextCancelled(g); err != nil {
		return fmt.Errorf("waiting for error group: %w", err)
	}

	consumer, err := watcher.RegisterConsumer(
		c.ctx, c.consumerID,
		composeControllerWatcherFilters(),
	)
	if err != nil {
		return fmt.Errorf("failed to create consumer for entity controller: %w", err)
	}

	c.mux.Lock()
	c.consumer = consumer
	c.running = true
	c.quit = make(chan struct{})
	c.mux.Unlock()

	go c.loop()

	return nil
}

func (c *Controller) Stop() error {
	slog.DebugContext(c.ctx, "stopping entity controller", "entity", c.consumerID)
	c.mux.Lock()
	defer c.mux.Unlock()
	if !c.running {
		return nil
	}
	slog.DebugContext(c.ctx, "stopping entity controller")

	for entityID, worker := range c.Entities {
		if err := worker.Stop(); err != nil {
			slog.ErrorContext(c.ctx, "stopping worker for entity", "entity_id", entityID, "error", err)
		}
	}

	c.running = false
	close(c.quit)
	c.consumer.Close()
	slog.DebugContext(c.ctx, "stopped entity controller", "entity", c.consumerID)
	return nil
}

func (c *Controller) loop() {
	defer c.Stop()
	for {
		select {
		case payload := <-c.consumer.Watch():
			slog.InfoContext(c.ctx, "received payload")
			go c.handleWatcherEvent(payload)
		case <-c.ctx.Done():
			return
		case <-c.quit:
			return
		}
	}
}