package main

import (
	"encoding/json"
	"flag"
	"fmt"
	"io"
	"net/http"
	"os"
	"strings"
)

const (
	CurrentVersion = "v0.1.0"
	ReleaseURL     = "https://gitea.sanplex.xyz/Sansan/dimma/releases/latest"
)

type ReleaseInfo struct {
	TagName string `json:"tag_name"`
}

func main() {
	check := flag.Bool("check", false, "Check for updates")
	flag.Parse()

	if !*check {
		flag.Usage()
		return
	}

	fmt.Printf("Current version: %s\n", CurrentVersion)

	latestVersion, err := fetchLatestVersion()
	if err != nil {
		fmt.Printf("Error fetching latest version: %v\n", err)
		return
	}

	fmt.Printf("Latest version: %s\n", latestVersion)

	if compareVersions(latestVersion, CurrentVersion) > 0 {
		fmt.Printf("Update available: %s\n", latestVersion)
	} else {
		fmt.Println("Up to date")
	}
}

func fetchLatestVersion() (string, error) {
	resp, err := http.Get(ReleaseURL)
	if err != nil {
		return "", err
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return "", fmt.Errorf("HTTP %d", resp.StatusCode)
	}

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return "", err
	}

	// Gitea releases API returns JSON with tag_name
	var release ReleaseInfo
	if err := json.Unmarshal(body, &release); err != nil {
		// Try to extract from HTML if not JSON
		release.TagName = extractVersionFromHTML(string(body))
		if release.TagName == "" {
			return "", fmt.Errorf("failed to parse release info")
		}
	}

	return release.TagName, nil
}

func extractVersionFromHTML(html string) string {
	// Simple extraction from HTML (fallback for non-API URLs)
	// Looks for patterns like "v0.1.0" or "0.1.0"
	parts := strings.Split(html, "v")
	for _, part := range parts {
		if len(part) > 0 && part[0] >= '0' && part[0] <= '9' {
			version := "v" + strings.Split(part, "\"")[0]
			version = strings.Split(version, " ")[0]
			version = strings.Split(version, ">")[0]
			version = strings.TrimSpace(version)
			if version != "" {
				return version
			}
		}
	}
	return ""
}

func compareVersions(a, b string) int {
	// Simple version comparison (v0.1.0 format)
	a = strings.TrimPrefix(a, "v")
	b = strings.TrimPrefix(b, "v")
	return strings.Compare(a, b)
}