package comicverse

import (
	"context"
	"crypto/ed25519"
	"database/sql"
	"errors"
	"fmt"
	"io"
	"io/fs"
	"log/slog"
	"net/http"

	"code.capytal.cc/capytal/comicverse/assets"
	"code.capytal.cc/capytal/comicverse/internals/joinedfs"
	"code.capytal.cc/capytal/comicverse/repository"
	"code.capytal.cc/capytal/comicverse/router"
	"code.capytal.cc/capytal/comicverse/service"
	"code.capytal.cc/capytal/comicverse/templates"
	"code.capytal.cc/loreddev/x/tinyssert"
	"github.com/aws/aws-sdk-go-v2/service/s3"
)

func New(cfg Config, opts ...Option) (http.Handler, error) {
	app := &app{
		db:         cfg.DB,
		s3:         cfg.S3,
		bucket:     cfg.Bucket,
		privateKey: cfg.PrivateKey,
		publicKey:  cfg.PublicKey,

		assets:          assets.Files(),
		templates:       templates.Templates(),
		developmentMode: false,
		ctx:             context.Background(),

		assert: tinyssert.New(),
		logger: slog.New(slog.NewTextHandler(io.Discard, &slog.HandlerOptions{Level: slog.LevelError})),
	}

	for _, opt := range opts {
		opt(app)
	}

	if app.db == nil {
		return nil, errors.New("database interface must not be nil")
	}
	if app.s3 == nil {
		return nil, errors.New("s3 client must not be nil")
	}
	if app.privateKey == nil || len(app.privateKey) == 0 {
		return nil, errors.New("private key client must not be nil")
	}
	if app.publicKey == nil || len(app.publicKey) == 0 {
		return nil, errors.New("public key client must not be nil")
	}
	if app.bucket == "" {
		return nil, errors.New("bucket must not be a empty string")
	}

	if app.assets == nil {
		return nil, errors.New("static files must not be a nil interface")
	}
	if app.templates == nil {
		return nil, errors.New("templates must not be a nil interface")
	}

	if app.ctx == nil {
		return nil, errors.New("context must not be a nil interface")
	}

	if app.logger == nil {
		return nil, errors.New("logger must not be a nil interface")
	}

	if app.assert == nil {
		return nil, errors.New("assertions must not be a nil interface")
	}

	return app, app.setup()
}

type Config struct {
	DB         *sql.DB
	S3         *s3.Client
	Bucket     string
	PrivateKey ed25519.PrivateKey // TODO: Put this inside a service so we can easily rotate keys
	PublicKey  ed25519.PublicKey
}

type Option func(*app)

func WithContext(ctx context.Context) Option {
	return func(app *app) { app.ctx = ctx }
}

func WithAssets(f fs.FS) Option {
	return func(app *app) { app.assets = joinedfs.Join(f, app.assets) }
}

func WithTemplates(t templates.ITemplate) Option {
	return func(app *app) { app.templates = t }
}

func WithAssertions(a tinyssert.Assertions) Option {
	return func(app *app) { app.assert = a }
}

func WithLogger(l *slog.Logger) Option {
	return func(app *app) { app.logger = l }
}

func WithDevelopmentMode() Option {
	return func(app *app) { app.developmentMode = true }
}

type app struct {
	db         *sql.DB
	s3         *s3.Client
	bucket     string
	privateKey ed25519.PrivateKey
	publicKey  ed25519.PublicKey

	ctx context.Context

	assets          fs.FS
	templates       templates.ITemplate
	developmentMode bool

	handler http.Handler

	assert tinyssert.Assertions
	logger *slog.Logger
}

func (app *app) setup() error {
	app.assert.NotNil(app.db)
	app.assert.NotNil(app.s3)
	app.assert.NotZero(app.bucket)
	app.assert.NotNil(app.ctx)
	app.assert.NotNil(app.assets)
	app.assert.NotNil(app.logger)

	userRepository, err := repository.NewUser(app.ctx, app.db, app.logger.WithGroup("repository.user"), app.assert)
	if err != nil {
		return fmt.Errorf("app: failed to start user repository: %w", err)
	}

	tokenRepository, err := repository.NewToken(app.ctx, app.db, app.logger.WithGroup("repository.token"), app.assert)
	if err != nil {
		return fmt.Errorf("app: failed to start token repository: %w", err)
	}

	projectRepository, err := repository.NewProject(app.ctx, app.db, app.logger.WithGroup("repository.project"), app.assert)
	if err != nil {
		return fmt.Errorf("app: failed to start project repository: %w", err)
	}

	permissionRepository, err := repository.NewPermissions(app.ctx, app.db, app.logger.WithGroup("repository.permission"), app.assert)
	if err != nil {
		return fmt.Errorf("app: failed to start permission repository: %w", err)
	}

	userService := service.NewUser(userRepository, app.logger.WithGroup("service.user"), app.assert)
	tokenService := service.NewToken(service.TokenConfig{
		PrivateKey: app.privateKey,
		PublicKey:  app.publicKey,
		Repository: tokenRepository,
		Logger:     app.logger.WithGroup("service.token"),
		Assertions: app.assert,
	})
	projectService := service.NewProject(projectRepository, permissionRepository, app.logger.WithGroup("service.project"), app.assert)

	app.handler, err = router.New(router.Config{
		UserService:    userService,
		TokenService:   tokenService,
		ProjectService: projectService,

		Templates:    app.templates,
		DisableCache: app.developmentMode,
		Assets:       app.assets,

		Assertions: app.assert,
		Logger:     app.logger.WithGroup("router"),
	})
	if err != nil {
		return errors.Join(errors.New("unable to initiate router"), err)
	}

	return err
}

func (app *app) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	app.assert.NotNil(app.handler)
	app.handler.ServeHTTP(w, r)
}