package main

import (
	"context"
	"fmt"
	"net/http"
	"os"
	"os/signal"
	"syscall"
	"time"

	"github.com/prabhupadasays/spsays-bff/internal/config"
	"github.com/prabhupadasays/spsays-bff/internal/server"
	"go.uber.org/zap"
	"go.uber.org/zap/zapcore"
)

// newLogger builds the app logger, routing logs by level: Debug/Info/Warn go
// to stdout and only Error/Fatal/Panic go to stderr. Hosting platforms tag
// every stderr line as "error", so without this split a routine Debug/Info
// line shows up with a misleading error badge. Production uses JSON at Info+;
// development uses colored console at Debug+.
func newLogger(production bool) *zap.Logger {
	var encoder zapcore.Encoder
	minLevel := zapcore.DebugLevel
	if production {
		encoder = zapcore.NewJSONEncoder(zap.NewProductionEncoderConfig())
		minLevel = zapcore.InfoLevel
	} else {
		encCfg := zap.NewDevelopmentEncoderConfig()
		encCfg.EncodeLevel = zapcore.CapitalColorLevelEncoder
		encoder = zapcore.NewConsoleEncoder(encCfg)
	}

	low := zap.LevelEnablerFunc(func(l zapcore.Level) bool {
		return l >= minLevel && l < zapcore.ErrorLevel
	})
	high := zap.LevelEnablerFunc(func(l zapcore.Level) bool {
		return l >= zapcore.ErrorLevel
	})
	core := zapcore.NewTee(
		zapcore.NewCore(encoder, zapcore.Lock(os.Stdout), low),
		zapcore.NewCore(encoder, zapcore.Lock(os.Stderr), high),
	)
	return zap.New(core, zap.AddCaller(), zap.AddStacktrace(zapcore.ErrorLevel))
}

func main() {
	// Load config
	cfg, err := config.Load()
	if err != nil {
		fmt.Fprintf(os.Stderr, "failed to load config: %v\n", err)
		os.Exit(1)
	}

	// Initialize logger — routes normal logs to stdout, errors to stderr.
	logger := newLogger(cfg.Env == "production")
	defer logger.Sync()

	sugar := logger.Sugar()

	// Create server
	srv := server.New(cfg, logger)

	// Start HTTP server
	httpServer := &http.Server{
		Addr:         fmt.Sprintf(":%d", cfg.Port),
		Handler:      srv.Router(),
		ReadTimeout:  15 * time.Second,
		WriteTimeout: 15 * time.Second,
		IdleTimeout:  60 * time.Second,
	}

	// Graceful shutdown
	go func() {
		sugar.Infof("🚀 Server starting on port %d (%s)", cfg.Port, cfg.Env)
		if err := httpServer.ListenAndServe(); err != nil && err != http.ErrServerClosed {
			sugar.Fatalf("server error: %v", err)
		}
	}()

	quit := make(chan os.Signal, 1)
	signal.Notify(quit, syscall.SIGINT, syscall.SIGTERM)
	<-quit

	sugar.Info("🛑 Shutting down server...")

	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
	defer cancel()

	if err := httpServer.Shutdown(ctx); err != nil {
		sugar.Fatalf("forced shutdown: %v", err)
	}

	// Close connections
	srv.Close()

	sugar.Info("✅ Server stopped gracefully")
}