package main

import (
	"context"
	"encoding/json"
	"errors"
	"flag"
	"fmt"
	"os"
	"time"

	"github.com/jackc/pgx/v5/pgxpool"

	"github.com/loyaly/behavision-server/internal/provision"
	"github.com/loyaly/behavision-server/internal/secret"
)

// runProvision handles `behavision-server provision ...`.
//
// Everything it prints that is a secret is printed ONCE and never stored in
// recoverable form afterwards, so the operator has to copy it now. That is the
// point: a credential a support engineer can look up later is a credential
// anyone with support access has.
func runProvision(args []string) error {
	if len(args) == 0 {
		return errors.New(provisionUsage)
	}
	dsn := os.Getenv("DATABASE_URL")
	if dsn == "" {
		return errors.New("DATABASE_URL is required")
	}
	ctx, cancel := context.WithTimeout(context.Background(), 60*time.Second)
	defer cancel()

	pool, err := pgxpool.New(ctx, dsn)
	if err != nil {
		return err
	}
	defer pool.Close()
	if err := pool.Ping(ctx); err != nil {
		return fmt.Errorf("database unreachable: %w", err)
	}

	box, boxErr := secret.FromEnv("BEHAVISION_SECRET_KEY")
	p := &provision.Provisioner{Pool: pool, Secrets: box}

	switch args[0] {
	case "client":
		fs := flag.NewFlagSet("provision client", flag.ContinueOnError)
		slug := fs.String("slug", "", "short name used in MQTT topics, e.g. acme")
		name := fs.String("name", "", "display name")
		if err := fs.Parse(args[1:]); err != nil {
			return err
		}
		if *slug == "" || *name == "" {
			return errors.New("provision client -slug acme -name \"Acme Retail\"")
		}
		id, err := p.CreateClient(ctx, *slug, *name)
		if err != nil {
			return err
		}
		fmt.Printf("client %s created: %s\n", *slug, id)
		return nil

	case "site":
		fs := flag.NewFlagSet("provision site", flag.ContinueOnError)
		client := fs.String("client", "", "client slug")
		slug := fs.String("slug", "", "site slug, e.g. store1")
		name := fs.String("name", "", "display name")
		tz := fs.String("tz", "Asia/Kolkata", "IANA timezone; footfall is bucketed in it")
		if err := fs.Parse(args[1:]); err != nil {
			return err
		}
		if *client == "" || *slug == "" || *name == "" {
			return errors.New("provision site -client acme -slug store1 -name \"Acme Chennai\"")
		}
		if boxErr != nil {
			return boxErr
		}
		res, err := p.CreateSite(ctx, *client, *slug, *name, *tz)
		if err != nil {
			return err
		}
		fmt.Printf("site created: %s\n", res.SiteID)
		fmt.Printf("\nAdd this broker user to Mosquitto, then this site can publish:\n\n")
		fmt.Printf("  mosquitto_passwd -b /mosquitto/config/passwd %s '%s'\n\n",
			res.Username, res.Password)
		// The broker keeps a hash; we keep it sealed. Neither side can show it
		// again, which is why it is printed here in full.
		fmt.Printf("The password is stored encrypted and handed out only at "+
			"enrolment.\nIt is not recoverable from the logs. Copy it now.\n")
		return nil

	case "user":
		fs := flag.NewFlagSet("provision user", flag.ContinueOnError)
		client := fs.String("client", "", "client slug (omit for a platform admin)")
		email := fs.String("email", "", "sign-in address")
		role := fs.String("role", "manager", "owner | manager | staff | admin")
		name := fs.String("name", "", "full name")
		pw := fs.String("password", "", "leave empty to generate one")
		if err := fs.Parse(args[1:]); err != nil {
			return err
		}
		id, password, err := p.CreateUser(ctx, *client, *email, *role, *name, *pw)
		if err != nil {
			return err
		}
		fmt.Printf("user %s created: %s (%s)\n", *email, id, *role)
		if *pw == "" {
			fmt.Printf("\n  password: %s\n\n", password)
			fmt.Printf("Stored only as a bcrypt hash. Copy it now.\n")
		}
		return nil

	case "token":
		fs := flag.NewFlagSet("provision token", flag.ContinueOnError)
		client := fs.String("client", "", "client slug")
		site := fs.String("site", "", "site slug")
		label := fs.String("label", "", "note, e.g. \"front counter PC\"")
		days := fs.Int("days", 7, "how long the code stays valid")
		if err := fs.Parse(args[1:]); err != nil {
			return err
		}
		if *client == "" || *site == "" {
			return errors.New("provision token -client acme -site store1")
		}
		code, expires, err := p.IssueEnrolmentToken(ctx, *client, *site, *label,
			time.Duration(*days)*24*time.Hour)
		if err != nil {
			return err
		}
		fmt.Printf("\n  installation code: %s\n\n", code)
		fmt.Printf("Valid once, until %s.\n", expires.Format(time.RFC1123))
		return nil

	case "key":
		// JSON by default so it can be piped straight into an env file without
		// somebody retyping 44 base64 characters and getting one wrong - and
		// -raw for a shell, because the obvious `export KEY=$(... | tail -1)`
		// captures the whole JSON object and hands the server a key it cannot
		// parse. That was in RUN.md, on the first step of the first setup.
		fs := flag.NewFlagSet("provision key", flag.ContinueOnError)
		raw := fs.Bool("raw", false, "print only the key, for $(...) in a shell")
		if err := fs.Parse(args[1:]); err != nil {
			return err
		}
		k, err := secret.NewKey()
		if err != nil {
			return err
		}
		if *raw {
			fmt.Println(k)
			fmt.Fprintln(os.Stderr,
				"\nStore this with the database backups' key material, NOT beside them.")
			return nil
		}
		out, _ := json.Marshal(map[string]string{"BEHAVISION_SECRET_KEY": k})
		fmt.Println(string(out))
		fmt.Fprintln(os.Stderr,
			"\nStore this with the database backups' key material, NOT beside them.\n"+
				"Losing it makes every site's broker password unrecoverable;\n"+
				"leaking it with a database dump hands them all over.")
		return nil
	}
	return errors.New(provisionUsage)
}

const provisionUsage = `usage:
  behavision-server provision key
  behavision-server provision client -slug acme -name "Acme Retail"
  behavision-server provision site   -client acme -slug store1 -name "Chennai" -tz Asia/Kolkata
  behavision-server provision user   -client acme -email a@acme.com -role manager
  behavision-server provision token  -client acme -site store1`