package heroku

import (
	"context"
	"fmt"
	"log"
	"strings"
	"sync"
	"time"

	"github.com/cyberdelia/heroku-go/v3"
	"github.com/hashicorp/terraform/helper/resource"
	"github.com/hashicorp/terraform/helper/schema"
)

// Global lock to prevent parallelism for heroku_addon since
// the Heroku API cannot handle a single application requesting
// multiple addons simultaneously.
var addonLock sync.Mutex

func resourceHerokuAddon() *schema.Resource {
	return &schema.Resource{
		Create: resourceHerokuAddonCreate,
		Read:   resourceHerokuAddonRead,
		Update: resourceHerokuAddonUpdate,
		Delete: resourceHerokuAddonDelete,

		Schema: map[string]*schema.Schema{
			"app": {
				Type:     schema.TypeString,
				Required: true,
				ForceNew: true,
			},

			"plan": {
				Type:     schema.TypeString,
				Required: true,
			},

			"config": {
				Type:     schema.TypeList,
				Optional: true,
				ForceNew: true,
				Elem: &schema.Schema{
					Type: schema.TypeMap,
				},
			},

			"provider_id": {
				Type:     schema.TypeString,
				Computed: true,
			},

			"config_vars": {
				Type:     schema.TypeList,
				Computed: true,
				Elem: &schema.Schema{
					Type: schema.TypeString,
				},
			},
		},
	}
}

func resourceHerokuAddonCreate(d *schema.ResourceData, meta interface{}) error {
	addonLock.Lock()
	defer addonLock.Unlock()

	client := meta.(*heroku.Service)

	app := d.Get("app").(string)
	opts := heroku.AddOnCreateOpts{Plan: d.Get("plan").(string)}

	if v := d.Get("config"); v != nil {
		config := make(map[string]string)
		for _, v := range v.([]interface{}) {
			for k, v := range v.(map[string]interface{}) {
				config[k] = v.(string)
			}
		}

		opts.Config = &config
	}

	log.Printf("[DEBUG] Addon create configuration: %#v, %#v", app, opts)
	a, err := client.AddOnCreate(context.TODO(), app, opts)
	if err != nil {
		return err
	}

	d.SetId(a.ID)
	log.Printf("[INFO] Addon ID: %s", d.Id())

	// Wait for the Addon to be provisioned
	log.Printf("[DEBUG] Waiting for Addon (%s) to be provisioned", d.Id())
	stateConf := &resource.StateChangeConf{
		Pending: []string{"provisioning"},
		Target:  []string{"provisioned"},
		Refresh: AddOnStateRefreshFunc(client, app, d.Id()),
		Timeout: 20 * time.Minute,
	}

	if _, err := stateConf.WaitForState(); err != nil {
		return fmt.Errorf("Error waiting for Addon (%s) to be provisioned: %s", d.Id(), err)
	}
	log.Printf("[INFO] Addon provisioned: %s", d.Id())

	return resourceHerokuAddonRead(d, meta)
}

func resourceHerokuAddonRead(d *schema.ResourceData, meta interface{}) error {
	client := meta.(*heroku.Service)

	addon, err := resourceHerokuAddonRetrieveByApp(
		d.Get("app").(string), d.Id(), client)
	if err != nil {
		return err
	}

	// Determine the plan. If we were configured without a specific plan,
	// then just avoid the plan altogether (accepting anything that
	// Heroku sends down).
	plan := addon.Plan.Name
	if v := d.Get("plan").(string); v != "" {
		if idx := strings.IndexRune(v, ':'); idx == -1 {
			idx = strings.IndexRune(plan, ':')
			if idx > -1 {
				plan = plan[:idx]
			}
		}
	}

	d.Set("name", addon.Name)
	d.Set("plan", plan)
	d.Set("provider_id", addon.ProviderID)
	if err := d.Set("config_vars", addon.ConfigVars); err != nil {
		return err
	}

	return nil
}

func resourceHerokuAddonUpdate(d *schema.ResourceData, meta interface{}) error {
	client := meta.(*heroku.Service)

	app := d.Get("app").(string)

	if d.HasChange("plan") {
		ad, err := client.AddOnUpdate(
			context.TODO(), app, d.Id(), heroku.AddOnUpdateOpts{Plan: d.Get("plan").(string)})
		if err != nil {
			return err
		}

		// Store the new ID
		d.SetId(ad.ID)
	}

	return resourceHerokuAddonRead(d, meta)
}

func resourceHerokuAddonDelete(d *schema.ResourceData, meta interface{}) error {
	client := meta.(*heroku.Service)

	log.Printf("[INFO] Deleting Addon: %s", d.Id())

	// Destroy the app
	_, err := client.AddOnDelete(context.TODO(), d.Get("app").(string), d.Id())
	if err != nil {
		return fmt.Errorf("Error deleting addon: %s", err)
	}

	d.SetId("")
	return nil
}

func resourceHerokuAddonRetrieve(id string, client *heroku.Service) (*heroku.AddOn, error) {
	addon, err := client.AddOnInfo(context.TODO(), id)

	if err != nil {
		return nil, fmt.Errorf("Error retrieving addon: %s", err)
	}

	return addon, nil
}

func resourceHerokuAddonRetrieveByApp(app string, id string, client *heroku.Service) (*heroku.AddOn, error) {
	addon, err := client.AddOnInfoByApp(context.TODO(), app, id)

	if err != nil {
		return nil, fmt.Errorf("Error retrieving addon: %s", err)
	}

	return addon, nil
}

// AddOnStateRefreshFunc returns a resource.StateRefreshFunc that is used to
// watch an AddOn.
func AddOnStateRefreshFunc(client *heroku.Service, appID, addOnID string) resource.StateRefreshFunc {
	return func() (interface{}, string, error) {
		addon, err := resourceHerokuAddonRetrieveByApp(appID, addOnID, client)

		if err != nil {
			return nil, "", err
		}

		// The type conversion here can be dropped when the vendored version of
		// heroku-go is updated.
		return (*heroku.AddOn)(addon), addon.State, nil
	}
}