package reports

import (
	_ "embed"
	"fmt"
	"image/color"
	"image/jpeg"
	"image/png"
	"os"
	"path/filepath"
	"strings"
	"time"

	"github.com/atridad/wrapped-cli/pkg/config"
	"github.com/atridad/wrapped-cli/pkg/models"
	"github.com/fogleman/gg"
)

//go:embed BitCount.ttf
var fontData []byte

var fontPath string

func init() {
	tmpDir := os.TempDir()
	fontPath = filepath.Join(tmpDir, "BitCount.ttf")
	if _, err := os.Stat(fontPath); os.IsNotExist(err) {
		if err := os.WriteFile(fontPath, fontData, 0644); err != nil {
			fmt.Fprintf(os.Stderr, "Warning: failed to write embedded font: %v\n", err)
		}
	}
}

const (
	canvasW = 2100
	canvasH = 1740
	gridGap = 30
	radius  = 36
	unitCol = 487
	twoCol  = 1005
	fourCol = 2040
)

var (
	bgColor       = color.RGBA{9, 9, 11, 255}
	cardBg        = color.RGBA{24, 24, 27, 255}
	cardBgPurple  = color.RGBA{30, 20, 36, 255}
	cardBgBlue    = color.RGBA{15, 23, 42, 255}
	accentMagenta = color.RGBA{220, 90, 255, 255}
	accentCyan    = color.RGBA{0, 244, 255, 255}
	accentOrange  = color.RGBA{255, 150, 0, 255}
	accentGreen   = color.RGBA{34, 255, 100, 255}
	accentBlue    = color.RGBA{100, 180, 255, 255}
	textPrimary   = color.RGBA{255, 255, 255, 255}
	textSecondary = color.RGBA{200, 200, 215, 255}
	textMuted     = color.RGBA{150, 150, 170, 255}
	borderColor   = color.RGBA{60, 60, 70, 255}
	barTrack      = color.RGBA{50, 50, 65, 255}
)

type bentoCard struct {
	x, y, w, h float64
	bg         color.RGBA
	accent     color.RGBA
}

func col(n int) float64 {
	return float64(gridGap + n*(unitCol+gridGap))
}

func cardLayout() []bentoCard {
	r1y := float64(gridGap)
	r1h := float64(360)
	r2y := r1y + r1h + gridGap
	r2h := float64(360)
	r3y := r2y + r2h + gridGap
	r3h := float64(450)
	r4y := r3y + r3h + gridGap
	r4h := float64(420)

	return []bentoCard{
		{col(0), r1y, twoCol, r1h, cardBgPurple, accentMagenta},
		{col(2), r1y, unitCol, r1h, cardBg, accentOrange},
		{col(3), r1y, unitCol, r1h, cardBg, accentCyan},
		{col(0), r2y, unitCol, r2h, cardBg, accentGreen},
		{col(1), r2y, unitCol, r2h, cardBg, accentOrange},
		{col(2), r2y, twoCol, r2h, cardBgBlue, accentBlue},
		{col(0), r3y, fourCol, r3h, cardBg, accentMagenta},
		{col(0), r4y, fourCol, r4h, cardBg, accentCyan},
	}
}

func loadFont(dc *gg.Context, size float64) {
	if err := dc.LoadFontFace(fontPath, size); err != nil {
		fmt.Fprintf(os.Stderr, "Warning: failed to load embedded font: %v\n", err)
	}
}

func drawCard(dc *gg.Context, c bentoCard) {
	dc.DrawRoundedRectangle(c.x, c.y, c.w, c.h, radius)
	dc.SetColor(c.bg)
	dc.Fill()
	dc.DrawRoundedRectangle(c.x, c.y, c.w, c.h, radius)
	dc.SetColor(borderColor)
	dc.SetLineWidth(1)
	dc.Stroke()
}

func label(dc *gg.Context, c bentoCard, text string) {
	loadFont(dc, 18)
	dc.SetColor(textSecondary)
	dc.DrawString(text, c.x+36, c.y+48)
}

func bigNum(dc *gg.Context, c bentoCard, value, sub string) {
	loadFont(dc, 96)
	dc.SetColor(c.accent)
	dc.DrawString(value, c.x+36, c.y+165)

	if sub != "" {
		loadFont(dc, 21)
		dc.SetColor(textSecondary)
		dc.DrawString(sub, c.x+36, c.y+204)
	}
}

func bigText(dc *gg.Context, c bentoCard, value string, size float64) {
	loadFont(dc, size*1.5)
	dc.SetColor(c.accent)
	dc.DrawString(value, c.x+36, c.y+165)
}

func filledBar(dc *gg.Context, x, y, totalW, h, pct float64, fill color.RGBA) {
	dc.DrawRoundedRectangle(x, y, totalW, h, 6)
	dc.SetColor(barTrack)
	dc.Fill()

	fillW := totalW * pct
	if fillW < 8 {
		fillW = 8
	}
	dc.DrawRoundedRectangle(x, y, fillW, h, 6)
	dc.SetColor(fill)
	dc.Fill()
}

func renderCommitsCard(dc *gg.Context, c bentoCard, stats *models.UserStats) {
	label(dc, c, "TOTAL COMMITS")
	bigNum(dc, c, formatNumber(stats.TotalCommits),
		fmt.Sprintf("%.1f commits per day on average", stats.AverageCommitsPerDay))

	dc.DrawRoundedRectangle(c.x+36, c.y+c.h-60, c.w-72, 15, 7)
	dc.SetColor(color.RGBA{70, 50, 90, 255})
	dc.Fill()
	dc.DrawRoundedRectangle(c.x+36, c.y+c.h-60, (c.w-72)*0.72, 15, 7)
	dc.SetColor(c.accent)
	dc.Fill()
}

func renderReposCard(dc *gg.Context, c bentoCard, stats *models.UserStats) {
	label(dc, c, "REPOSITORIES")
	bigNum(dc, c, formatNumber(stats.TotalRepositories), "worked on this year")

	y := c.y + 240
	maxW := c.w - 72
	for i, repo := range stats.TopRepositories {
		if i >= 3 {
			break
		}
		loadFont(dc, 18)
		dc.SetColor(textMuted)
		dc.DrawString(truncate(repo.Name, maxW, dc), c.x+36, y)
		y += 36
	}
}

func renderActiveDayCard(dc *gg.Context, c bentoCard, stats *models.UserStats) {
	label(dc, c, "MOST ACTIVE DAY")
	bigText(dc, c, stats.MostActiveDay, 72)

	if len(stats.CommitsByWeekday) > 0 {
		loadFont(dc, 21)
		dc.SetColor(textSecondary)
		dc.DrawString(
			fmt.Sprintf("%d commits that day", stats.CommitsByWeekday[0].Count),
			c.x+36, c.y+204,
		)
	}
}

func renderAvgCard(dc *gg.Context, c bentoCard, stats *models.UserStats) {
	label(dc, c, "AVG COMMITS / DAY")
	bigNum(dc, c, fmt.Sprintf("%.1f", stats.AverageCommitsPerDay), "daily average")
}

func renderActiveMonthCard(dc *gg.Context, c bentoCard, stats *models.UserStats) {
	label(dc, c, "MOST ACTIVE MONTH")
	bigText(dc, c, stats.MostActiveMonth, 66)
}

func renderTopRepoCard(dc *gg.Context, c bentoCard, stats *models.UserStats) {
	label(dc, c, "TOP REPOSITORY")

	if len(stats.TopRepositories) == 0 {
		return
	}

	top := stats.TopRepositories[0]
	maxW := c.w - 72

	loadFont(dc, 48)
	dc.SetColor(c.accent)
	dc.DrawString(truncate(top.Name, maxW, dc), c.x+36, c.y+150)

	loadFont(dc, 19)
	dc.SetColor(textSecondary)
	dc.DrawString("your #1 repository this year", c.x+36, c.y+189)

	y := c.y + 246
	for i := 1; i < len(stats.TopRepositories) && i < 4; i++ {
		loadFont(dc, 18)
		dc.SetColor(textMuted)
		dc.DrawString(
			fmt.Sprintf("#%d  %s", i+1, truncate(stats.TopRepositories[i].Name, maxW-45, dc)),
			c.x+36, y,
		)
		y += 36
	}
}

func renderLanguagesCard(dc *gg.Context, c bentoCard, stats *models.UserStats) {
	label(dc, c, "LANGUAGES")

	if len(stats.Languages) == 0 {
		loadFont(dc, 22)
		dc.SetColor(textSecondary)
		dc.DrawString("No language data available.", c.x+36, c.y+150)
		return
	}

	const (
		numCols    = 2
		rowsPerCol = 5
		rowH       = 72.0
		startY     = 90.0
		labelW     = 165.0
		countW     = 135.0
		barH       = 21.0
	)

	maxCount := stats.Languages[0].Count
	halfW := (c.w - 72 - gridGap) / 2

	for i, lang := range stats.Languages {
		if i >= numCols*rowsPerCol {
			break
		}

		colIdx := i / rowsPerCol
		rowIdx := i % rowsPerCol

		baseX := c.x + 36 + float64(colIdx)*(halfW+float64(gridGap))
		baseY := c.y + startY + float64(rowIdx)*rowH

		pct := float64(lang.Count) / float64(maxCount)
		barW := halfW - labelW - countW - 15

		loadFont(dc, 19)
		dc.SetColor(textPrimary)
		dc.DrawString(truncatePx(lang.Language, labelW-12, dc), baseX, baseY+18)

		filledBar(dc, baseX+labelW, baseY+3, barW, barH, pct, c.accent)

		loadFont(dc, 18)
		dc.SetColor(textSecondary)
		dc.DrawString(
			fmt.Sprintf("%d  %.1f%%", lang.Count, lang.Percent),
			baseX+labelW+barW+15, baseY+19,
		)
	}
}

func renderActivityCard(dc *gg.Context, c bentoCard, stats *models.UserStats) {
	label(dc, c, "ACTIVITY PATTERNS")

	const (
		startY = 81.0
		rowH   = 42.0
		labelW = 66.0
		countW = 75.0
		barH   = 21.0
	)

	halfW := (c.w - 72 - float64(gridGap)) / 2
	lx := c.x + 36

	loadFont(dc, 18)
	dc.SetColor(textSecondary)
	dc.DrawString("By Weekday", lx, c.y+startY)

	if len(stats.CommitsByWeekday) > 0 {
		maxC := stats.CommitsByWeekday[0].Count
		barW := halfW - labelW - countW - 15

		for i, day := range stats.CommitsByWeekday {
			if i >= 7 {
				break
			}
			by := c.y + startY + 36 + float64(i)*rowH

			loadFont(dc, 18)
			dc.SetColor(textPrimary)
			dc.DrawString(day.Day[:3], lx, by+18)

			pct := float64(day.Count) / float64(maxC)
			filledBar(dc, lx+labelW, by+3, barW, barH, pct, accentCyan)

			loadFont(dc, 16)
			dc.SetColor(textMuted)
			dc.DrawString(formatNumber(day.Count), lx+labelW+barW+12, by+18)
		}
	}

	rx := c.x + 36 + halfW + float64(gridGap)

	loadFont(dc, 18)
	dc.SetColor(textSecondary)
	dc.DrawString("By Month", rx, c.y+startY)

	if len(stats.CommitsByMonth) > 0 {
		maxC := stats.CommitsByMonth[0].Count
		barW := halfW - labelW - countW - 15

		for i, month := range stats.CommitsByMonth {
			if i >= 7 {
				break
			}
			by := c.y + startY + 36 + float64(i)*rowH

			loadFont(dc, 18)
			dc.SetColor(textPrimary)
			dc.DrawString(month.Date.Format("Jan"), rx, by+18)

			pct := float64(month.Count) / float64(maxC)
			filledBar(dc, rx+labelW, by+3, barW, barH, pct, accentOrange)

			loadFont(dc, 16)
			dc.SetColor(textMuted)
			dc.DrawString(formatNumber(month.Count), rx+labelW+barW+12, by+18)
		}
	}
}

func formatNumber(n int) string {
	switch {
	case n >= 1_000_000:
		return fmt.Sprintf("%.1fM", float64(n)/1_000_000)
	case n >= 1_000:
		return fmt.Sprintf("%.1fK", float64(n)/1_000)
	default:
		return fmt.Sprintf("%d", n)
	}
}

func truncate(s string, maxPx float64, dc *gg.Context) string {
	return truncatePx(s, maxPx, dc)
}

func truncatePx(s string, maxPx float64, dc *gg.Context) string {
	w, _ := dc.MeasureString(s)
	if w <= maxPx {
		return s
	}
	for len(s) > 1 {
		s = s[:len(s)-1]
		w, _ = dc.MeasureString(s + "…")
		if w <= maxPx {
			return s + "…"
		}
	}
	return s
}

func ExportReportAsImage(stats *models.UserStats, format string) (string, error) {
	resultsDir, err := config.GetResultsDir()
	if err != nil {
		return "", err
	}

	dc := gg.NewContext(canvasW, canvasH)
	dc.SetColor(bgColor)
	dc.Clear()

	cards := cardLayout()
	for _, c := range cards {
		drawCard(dc, c)
	}

	renderCommitsCard(dc, cards[0], stats)
	renderReposCard(dc, cards[1], stats)
	renderActiveDayCard(dc, cards[2], stats)
	renderAvgCard(dc, cards[3], stats)
	renderActiveMonthCard(dc, cards[4], stats)
	renderTopRepoCard(dc, cards[5], stats)
	renderLanguagesCard(dc, cards[6], stats)
	renderActivityCard(dc, cards[7], stats)

	now := time.Now()
	timestamp := now.Format("2006-01-02 15-04-05")
	filenameWithExt := fmt.Sprintf("%s - Gitea Wrapped.%s", timestamp, format)
	filename := filepath.Join(resultsDir, filenameWithExt)

	switch format {
	case "png":
		f, err := os.Create(filename)
		if err != nil {
			return "", err
		}
		defer f.Close()
		if err := png.Encode(f, dc.Image()); err != nil {
			return "", err
		}
	case "jpg", "jpeg":
		f, err := os.Create(filename)
		if err != nil {
			return "", err
		}
		defer f.Close()
		if err := jpeg.Encode(f, dc.Image(), &jpeg.Options{Quality: 92}); err != nil {
			return "", err
		}
	default:
		return "", fmt.Errorf("unsupported format: %s", format)
	}

	return filenameWithExt, nil
}

func GenerateReportImage(stats *models.UserStats, format string) (string, error) {
	return ExportReportAsImage(stats, format)
}

func stripANSI(s string) string {
	b := make([]byte, 0, len(s))
	inEscape := false
	for i := 0; i < len(s); i++ {
		if s[i] == '\x1b' {
			inEscape = true
		} else if inEscape && s[i] == 'm' {
			inEscape = false
		} else if !inEscape {
			b = append(b, s[i])
		}
	}
	return string(b)
}

func getTextColor(line string) color.Color {
	if strings.Contains(line, "Overview") ||
		strings.Contains(line, "Languages") ||
		strings.Contains(line, "Activity") {
		return color.RGBA{0, 255, 255, 255}
	}
	return color.RGBA{200, 200, 200, 255}
}