handler.go

package main

import (
	"encoding/json"
	"image"
	"math"
	"net/http"

	"github.com/wwgberlin/go-funk/audio"
	"github.com/wwgberlin/go-funk/renderer"
	"github.com/wwgberlin/go-funk/sampler"
)

func handler(data audio.WavData, defaults *RequestData, rdr renderer.RenderFunc) func(w http.ResponseWriter, req *http.Request) {
	return func(w http.ResponseWriter, r *http.Request) {
		reqData, err := parseRequest(r, defaults)
		if err != nil {
			http.Error(w, err.Error(), http.StatusBadRequest)
			return
		}

		compressed, err := sampler.Compress(data.Samples, reqData.Conf.Count, reqData.Sampler)
		if err != nil {
			http.Error(w, err.Error(), http.StatusBadRequest)
			return
		}

		rdr(w, renderer.Project(compressed, reqData.Conf.Height), data.Duration, reqData.Conf)
	}
}

func samplesHandler(data audio.WavData) func(w http.ResponseWriter, r *http.Request) {
	return func(w http.ResponseWriter, r *http.Request) {
		enc := json.NewEncoder(w)
		enc.Encode(data.Samples)
	}
}

func gifHandler(data audio.WavData) func(w http.ResponseWriter, req *http.Request) {
	defaults := RequestData{
		Sampler: sampler.AbsAvg,
		Conf: renderer.Config{
			Width:   50,
			Height:  100,
			Count:   3000,
			Colorer: renderer.Colors["black"],
		},
	}
	return handler(data, &defaults, renderer.MakeGif)
}

func gif2Handler(data audio.WavData) func(w http.ResponseWriter, req *http.Request) {

	defaults := RequestData{
		Sampler: sampler.AbsAvg,
		Conf: renderer.Config{
			Width:   50,
			Height:  100,
			Count:   3000,
			Colorer: renderer.Colors["black"],
		},
	}
	return handler(data, &defaults, renderer.MakeGif2)
}

func gopherHandler(data audio.WavData, img image.Image) func(w http.ResponseWriter, req *http.Request) {
	defaults := RequestData{
		Sampler: sampler.AbsAvg,
		Conf: renderer.Config{
			Width:   100,
			Height:  100,
			Count:   3000,
			Colorer: renderer.Colorer{ColorGopherFunc(img), ColorGopherPalette},
		},
	}
	return handler(data, &defaults, renderer.Gopher)
}

func waveformHandler(data audio.WavData) func(w http.ResponseWriter, r *http.Request) {
	defaults := RequestData{
		Sampler: sampler.AbsAvg,
		Conf: renderer.Config{
			Width:   1200,
			Count:   1200,
			Height:  math.MaxUint8,
			Colorer: renderer.Colors["black"],
		},
	}

	return handler(data, &defaults, renderer.DrawWaveform)
}