package downloader

import (
	"fmt"
	"math/rand"
	"os"
	"time"

	"github.com/briandowns/spinner"
	"github.com/mathismqn/godeez/internal/deezer"
	"github.com/mathismqn/godeez/internal/logger"
)

type downloadResult struct {
	skipped  bool
	path     string
	warnings []string
	err      error
}

type downloadStats struct {
	downloaded int
	skipped    int
	failed     int
	warnings   int
}

type progressTracker struct {
	logger       *logger.Logger
	stats        downloadStats
	totalSongs   int
	resourceType string
}

func newProgressTracker(logger *logger.Logger, totalSongs int, resourceType string) *progressTracker {
	return &progressTracker{
		logger:       logger,
		totalSongs:   totalSongs,
		resourceType: resourceType,
	}
}

func (pt *progressTracker) startDownload(index int, song *deezer.Song) *spinner.Spinner {
	trackProgress := fmt.Sprintf("[%d/%d]", index+1, pt.totalSongs)

	sp := spinner.New(spinner.CharSets[14], 100*time.Millisecond)
	sp.Writer = os.Stdout
	sp.Prefix = trackProgress + " "
	sp.Suffix = fmt.Sprintf(" Downloading: %s - %s", song.Artist, song.GetTitle())
	sp.Start()

	return sp
}

func (pt *progressTracker) handleResult(index int, song *deezer.Song, result downloadResult) {
	trackProgress := fmt.Sprintf("[%d/%d]", index+1, pt.totalSongs)
	songTitle := song.GetTitle()

	if result.skipped {
		pt.stats.skipped++
		fmt.Printf("%s ↷ Skipped: %s - %s\n    Already exists at: %s\n",
			trackProgress, song.Artist, songTitle, result.path)
		return
	}

	if result.err != nil {
		pt.stats.failed++
		pt.logger.Errorf("Failed to download %s - %s: %v\n", song.Artist, songTitle, result.err)
		fmt.Printf("%s ✖ Failed: %s - %s:\n    Error: %v\n",
			trackProgress, song.Artist, songTitle, result.err)
		return
	}

	pt.stats.downloaded++
	if len(result.warnings) > 0 {
		pt.stats.warnings++
	}
	pt.logger.Infof("Downloaded %s - %s\n", song.Artist, songTitle)

	symbol := "✔"
	if len(result.warnings) > 0 {
		symbol = "⚠"
	}
	fmt.Printf("%s %s Downloaded: %s - %s\n", trackProgress, symbol, song.Artist, songTitle)

	for _, w := range result.warnings {
		pt.logger.Warnf("Warning: %s\n", w)
		fmt.Printf("    Warning: %s\n", w)
	}
}

func (pt *progressTracker) printSummary(resourceTitle, resourceID, outputDir string, elapsed time.Duration) {
	if pt.stats.downloaded > 0 || pt.stats.failed > 0 {
		pt.logger.Infof("Resource %s (%s): %d downloaded, %d skipped, %d failed\n",
			resourceTitle, resourceID, pt.stats.downloaded, pt.stats.skipped, pt.stats.failed)
	}

	if pt.resourceType != "track" {
		warningsLine := ""
		if pt.stats.warnings > 0 {
			warningsLine = fmt.Sprintf("\nWarnings:       %d", pt.stats.warnings)
		}
		fmt.Printf(`
================== [ Summary ] ==================
Downloaded:     %d
Skipped:        %d
Failed:         %d%s
Elapsed time:   %s
Files saved to: %s
=================================================
`,
			pt.stats.downloaded,
			pt.stats.skipped,
			pt.stats.failed,
			warningsLine,
			elapsed.Round(time.Second),
			outputDir,
		)

		if pt.stats.downloaded > 0 {
			pt.showSupportMessage()
		}
	}
}

func (pt *progressTracker) showSupportMessage() {
	if rand.Float64() < 0.1 {
		fmt.Printf("\n💖 Enjoying GoDeez? Give us a ⭐ on GitHub: https://github.com/mathismqn/godeez\n")
	}
}