package main

import (
	"errors"
	"flag"
	"fmt"
	"io/fs"
	"math"
	"os"
	"path/filepath"
	"regexp"
	"sort"
	"strconv"
	"strings"
	"time"

	"github.com/fatih/color"
	"github.com/peterbourgon/ff/v3"
)

var (
	Version   = "develop"
	resultmap = map[string]string{
		"y": "✔",
		"n": "✘",
		"a": "◒",
		"u": "‽",
		"i": "ⓘ",
		"w": "⚠",
	}
	supernums = map[int]string{
		0: "⁰",
		1: "¹",
		2: "²",
		3: "³",
		4: "⁴",
		5: "⁵",
		6: "⁶",
		7: "⁷",
		8: "⁸",
		9: "⁹",
	}
	refresh = time.Hour * 24 * 30
)

func main() {
	fs := flag.NewFlagSet("caniuse", flag.ContinueOnError)
	versionFlag := fs.Bool("version", false, "Show the CLI version and exit")
	fs.BoolVar(versionFlag, "v", *versionFlag, "--version")

	if err := ff.Parse(fs, os.Args[1:],
		ff.WithEnvVarPrefix("CANIUSE"),
	); err != nil {
		fmt.Println(err)
		return
	}

	if *versionFlag {
		fmt.Printf("caniuse %s", Version)
		return
	}

	if fs.NArg() != 1 {
		fmt.Println("caniuse requires one argument")
		return
	}

	data, err := loadData()
	if err != nil {
		fmt.Printf("could not load data: %v", err)
	}

	query := fs.Arg(0)

	// Find a single feature
	if feat, ok := data.Data[query]; ok {
		fmt.Println(formatFeat(feat, data, false))
		return
	}

	// Find multiple features
	features := search(query, data)
	switch len(features) {
	case 0:
		fmt.Printf("%q not found", query)
	case 1:
		fmt.Println(formatFeat(data.Data[features[0]], data, false))
	default:
		for _, feat := range features {
			fmt.Println(formatFeat(data.Data[feat], data, true))
		}

	}
}

var clumpRe = regexp.MustCompile(`\W*`)

func search(query string, data Data) []string {
	var results []string
	query = strings.ToLower(query)
	for key, dat := range data.Data {
		matcher := clumpRe.ReplaceAllString(strings.ToLower(key+dat.Title+dat.Description+dat.Keywords+strings.Join(dat.Categories, "")), "")
		if strings.Contains(matcher, query) {
			results = append(results, key)
		}
	}
	return results
}

var replaceNoteRe = regexp.MustCompile(`[\r\n]+`)

func formatFeat(feat data, d Data, short bool) string {
	bold := color.New(color.Bold)

	var out strings.Builder
	out.WriteString(bold.Sprint(feat.Title))

	var p []string
	if feat.UsagePercY > 0 {
		p = append(p, fmt.Sprintf("%s %s%%", resultmap["y"], color.GreenString("%.2f", feat.UsagePercY)))
	}
	if feat.UsagePercA > 0 {
		p = append(p, fmt.Sprintf("%s %s%%", resultmap["a"], color.YellowString("%.2f", feat.UsagePercA)))
	}
	percentages := strings.Join(p, " ")
	out.WriteString(" " + percentages)

	status := fmt.Sprintf(" [%s]\n", d.Statuses[feat.Status])
	out.WriteString(status)

	if !short {
		out.WriteString("\t" + strings.TrimSpace(feat.Description) + "\n\n")
	}

	if short {
		out.WriteString("\t")
	}

	needNote := make(map[int]struct{})
	browsers := make([]string, 0, len(feat.Stats))
	for browser := range feat.Stats {
		if d.Agents[browser].Type != "desktop" {
			continue
		}
		browsers = append(browsers, browser)
	}
	sort.Strings(browsers)
	for _, browser := range browsers {
		agent := d.Agents[browser]
		stats := feat.Stats[browser]
		if !short {
			out.WriteString("\t")
		}
		out.WriteString(agent.Browser + " ")

		results := makeResults(agent, stats)
		if len(results) == 1 {
			results[0].version = ""
		}

		for _, result := range results {
			out.WriteString(makeResult(result, needNote))
		}
		if !short {
			out.WriteString("\n")
		}
	}

	if !short {
		out.WriteString("\n")
	}

	if !short {
		nums := make([]string, 0, len(feat.NotesByNum))
		for num := range feat.NotesByNum {
			nums = append(nums, num)
		}
		sort.Strings(nums)
		for _, num := range nums {
			n, _ := strconv.Atoi(num)
			if _, ok := needNote[n]; !ok {
				continue
			}
			out.WriteString(fmt.Sprintf("\t%s%s\n", color.YellowString(supernums[n]), feat.NotesByNum[num]))
		}
		if feat.Notes != "" {
			out.WriteString(fmt.Sprintf("\t%s %s", resultmap["i"], replaceNoteRe.ReplaceAllString(feat.Notes, " ")))
		}
	}

	return out.String()
}

var supportRe = regexp.MustCompile(`#(\d+)`)

func makeResult(stat browserStat, nums map[int]struct{}) string {
	support := string(stat.support[0])
	var out strings.Builder
	bace := "\u2800"
	if s, ok := resultmap[support]; ok {
		out.WriteString(s)
	} else {
		out.WriteString(support)
	}
	out.WriteString(bace)
	if stat.version != "" {
		out.WriteString(stat.version)
	}
	if strings.Contains(string(stat.support), "x") {
		out.WriteString("ᵖ")
	}
	match := supportRe.FindStringSubmatch(string(stat.support))
	if match != nil {
		num, _ := strconv.Atoi(match[1])
		nums[num] = struct{}{}
		out.WriteString(supernums[num])
	}
	if stat.usage > 0 {
		str := out.String()
		if string(str[len(str)-1]) != bace {
			out.WriteString(" ")
		}
		out.WriteString(fmt.Sprintf("(%f) ", math.Round(stat.usage*1)/1))
	}
	out.WriteString("  ")

	str := out.String()
	switch support {
	case "y":
		return color.GreenString(str)
	case "n":
		return color.RedString(str)
	case "a":
		return color.YellowString(str)
	default:
		return str
	}
}

func makeResults(browser browser, stats map[string]support) []browserStat {
	var results []browserStat
	var current browserStat
	for idx, version := range browser.Versions {
		if version == "" {
			continue
		}
		support := stats[version]

		var usage float64
		if u, ok := browser.UsageGlobal[version]; ok {
			usage = u
		}

		ver := version
		if len(browser.Versions) > idx {
			ver += "+"
		}

		if support[0] == 'p' {
			support = "n" + support[1:]
		}

		if current.version == "" || current.support != support {
			current = browserStat{
				version: ver,
				support: support,
				usage:   0,
			}
			results = append(results, current)
		}

		current.usage += usage
	}
	return results
}

func loadData() (Data, error) {
	var data Data

	cache, err := os.UserCacheDir()
	if err != nil {
		return data, fmt.Errorf("could not determine cache dir: %v", err)
	}

	caniuseCache := filepath.Join(cache, "caniuse")
	if err := os.MkdirAll(caniuseCache, os.ModePerm); err != nil {
		return data, fmt.Errorf("could not create dir %q: %v", caniuseCache, err)
	}

	dataPath := filepath.Join(caniuseCache, "data.json")
	fi, err := os.Stat(dataPath)
	if err != nil && !errors.Is(err, fs.ErrNotExist) {
		return data, fmt.Errorf("could not stat %q: %v", dataPath, err)
	} else if errors.Is(err, fs.ErrNotExist) || time.Since(fi.ModTime()) > refresh {
		color.Blue("updating caniuse data...")
		if err := Download(dataPath); err != nil {
			return data, fmt.Errorf("could not download data: %v", err)
		}
	}

	return Load(dataPath)
}