// Package middleware provides HTTP middleware for the API.
package middleware

import (
	"log/slog"
	"net/http"
	"time"
)

// responseWriter wraps http.ResponseWriter to capture the status code and track write state.
type responseWriter struct {
	http.ResponseWriter
	statusCode int  // HTTP status code written (default: 200)
	written    bool // whether WriteHeader or Write has been called
}

// WriteHeader captures the status code before writing.
func (rw *responseWriter) WriteHeader(code int) {
	if !rw.written {
		rw.statusCode = code
		rw.written = true
		rw.ResponseWriter.WriteHeader(code)
	}
}

// Write captures that data has been written.
func (rw *responseWriter) Write(b []byte) (int, error) {
	if !rw.written {
		rw.statusCode = http.StatusOK
		rw.written = true
	}
	return rw.ResponseWriter.Write(b)
}

// Logging middleware logs incoming requests with method, path, status code, and duration.
func Logging(logger *slog.Logger) func(next http.Handler) http.Handler {
	return func(next http.Handler) http.Handler {
		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			start := time.Now()
			rw := &responseWriter{
				ResponseWriter: w,
				statusCode:     http.StatusOK,
			}

			next.ServeHTTP(rw, r)

			duration := time.Since(start).Seconds()
			logger.Info(
				"request",
				slog.String("method", r.Method),
				slog.String("path", r.URL.Path),
				slog.Int("status", rw.statusCode),
				slog.Float64("duration_sec", duration),
			)
		})
	}
}