package app

import (
	"context"
	"errors"

	"github.com/rs/zerolog"
	"go.opentelemetry.io/otel/codes"
	"go.opentelemetry.io/otel/trace"

	"gitea.libretechconsulting.com/rmcguire/go-app/pkg/config"
	"gitea.libretechconsulting.com/rmcguire/go-app/pkg/otel"
	"gitea.libretechconsulting.com/rmcguire/go-app/pkg/srv"
)

type App struct {
	AppContext    context.Context
	HTTP          *AppHTTP
	cfg           *config.AppConfig
	l             *zerolog.Logger
	tracer        trace.Tracer
	shutdownFuncs []shutdownFunc
	appDone       chan interface{}
}

type AppHTTP struct {
	Funcs        []srv.HTTPFunc
	HealthChecks []srv.HealthCheckFunc
	httpDone     <-chan interface{}
}

type (
	healthCheckFunc func(context.Context) error
	shutdownFunc    func(context.Context) error
)

func (a *App) Done() <-chan interface{} {
	return a.appDone
}

func (a *App) MustRun() {
	if a.cfg != nil {
		panic(errors.New("already ran app trying to run"))
	}

	// Set up app
	a.cfg = config.MustFromCtx(a.AppContext)
	a.l = zerolog.Ctx(a.AppContext)
	a.shutdownFuncs = make([]shutdownFunc, 0)
	a.appDone = make(chan interface{})
	a.HTTP.httpDone = make(chan interface{})

	if len(a.HTTP.Funcs) < 1 {
		a.l.Warn().Msg("no http funcs provided, only serving health and metrics")
	}

	// Start OTEL
	a.initOTEL()
	var initSpan trace.Span
	_, initSpan = a.tracer.Start(a.AppContext, "init")

	// Start HTTP
	a.initHTTP()

	// Monitor app lifecycle
	go a.run()

	// Startup Complete
	a.l.Info().
		Str("name", a.cfg.Name).
		Str("version", a.cfg.Version).
		Str("logLevel", a.cfg.Logging.Level).
		Msg("app initialized")
	initSpan.SetStatus(codes.Ok, "")
	initSpan.End()
}

func (a *App) initHTTP() {
	var httpShutdown shutdownFunc
	httpShutdown, a.HTTP.httpDone = srv.MustInitHTTPServer(
		a.AppContext,
		a.HTTP.Funcs,
		a.HTTP.HealthChecks...,
	)
	a.shutdownFuncs = append(a.shutdownFuncs, httpShutdown)
}

func (a *App) initOTEL() {
	var otelShutdown shutdownFunc
	a.AppContext, otelShutdown = otel.Init(a.AppContext)
	a.shutdownFuncs = append(a.shutdownFuncs, otelShutdown)
	a.tracer = otel.MustTracerFromCtx(a.AppContext)
}