package gitea

import (
	"bufio"
	"crypto/tls"
	"encoding/json"
	"fmt"
	"net"
	"net/http"
	"net/url"
	"strings"
	"time"

	"software-station/internal/models"
)

func CheckSourceSecurity(serverURL, token, owner, repo string) *models.SourceSecurity {
	u, err := url.Parse(serverURL)
	if err != nil {
		return nil
	}
	domain := u.Hostname()

	security := &models.SourceSecurity{
		Domain: domain,
	}

	// TLS Check
	conf := &tls.Config{
		InsecureSkipVerify: false,
		MinVersion:         tls.VersionTLS12,
	}
	// Use port 443 for HTTPS domains
	port := "443"
	if u.Port() != "" {
		port = u.Port()
	}

	dialer := &net.Dialer{Timeout: 5 * time.Second}
	conn, err := tls.DialWithDialer(dialer, "tcp", net.JoinHostPort(domain, port), conf)
	if err == nil {
		security.TLSValid = true
		_ = conn.Close()
	}

	return security
}

func FetchUserGPGKeys(server, token, username string) ([]string, error) {
	url := fmt.Sprintf("%s/api/v1/users/%s/gpg_keys", server, username)
	req, err := http.NewRequest("GET", url, nil)
	if err != nil {
		return nil, err
	}

	if token != "" {
		req.Header.Set("Authorization", "token "+token)
	}

	client := &http.Client{Timeout: DefaultTimeout}
	resp, err := client.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("gitea gpg api returned status %d", resp.StatusCode)
	}

	var giteaKeys []struct {
		PublicKey string `json:"public_key"`
	}

	if err := json.NewDecoder(resp.Body).Decode(&giteaKeys); err != nil {
		return nil, err
	}

	keys := make([]string, len(giteaKeys))
	for i, k := range giteaKeys {
		keys[i] = k.PublicKey
	}

	return keys, nil
}

func FetchContributors(server, token, owner, repo string) ([]models.Contributor, error) {
	url := fmt.Sprintf("%s%s/%s/%s%s", server, RepoAPIPath, owner, repo, ContributorsSuffix)
	req, err := http.NewRequest("GET", url, nil)
	if err != nil {
		return nil, err
	}

	if token != "" {
		req.Header.Set("Authorization", "token "+token)
	}

	client := &http.Client{Timeout: DefaultTimeout}
	resp, err := client.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("gitea api returned status %d", resp.StatusCode)
	}

	var giteaContributors []struct {
		Username  string `json:"username"`
		AvatarURL string `json:"avatar_url"`
	}

	if err := json.NewDecoder(resp.Body).Decode(&giteaContributors); err != nil {
		return nil, err
	}

	contributors := make([]models.Contributor, len(giteaContributors))
	for i, c := range giteaContributors {
		keys, _ := FetchUserGPGKeys(server, token, c.Username)
		contributors[i] = models.Contributor{
			Username:  c.Username,
			AvatarURL: c.AvatarURL,
			GPGKeys:   keys,
		}
	}

	return contributors, nil
}

func DetectOS(filename string) string {
	lower := strings.ToLower(filename)

	if strings.HasSuffix(lower, ".whl") {
		if strings.Contains(lower, "win") || strings.Contains(lower, "windows") {
			return models.OSWindows
		}
		if strings.Contains(lower, "macosx") || strings.Contains(lower, "darwin") {
			return models.OSMacOS
		}
		if strings.Contains(lower, "linux") {
			return models.OSLinux
		}
		return models.OSUnknown
	}

	if strings.HasSuffix(lower, ".tar.gz") || strings.HasSuffix(lower, ".tgz") || strings.HasSuffix(lower, ".zip") {
		if strings.Contains(lower, "win") || strings.Contains(lower, "windows") {
			return models.OSWindows
		}
		if strings.Contains(lower, "mac") || strings.Contains(lower, "darwin") || strings.Contains(lower, "osx") {
			return models.OSMacOS
		}
		if strings.Contains(lower, "linux") {
			return models.OSLinux
		}
		if strings.Contains(lower, "freebsd") {
			return models.OSFreeBSD
		}
		if strings.Contains(lower, "openbsd") {
			return models.OSOpenBSD
		}
		return models.OSUnknown
	}

	osMap := []struct {
		patterns []string
		suffixes []string
		os       string
	}{
		{
			patterns: []string{"windows"},
			suffixes: []string{".exe", ".msi"},
			os:       models.OSWindows,
		},
		{
			patterns: []string{"linux"},
			suffixes: []string{".deb", ".rpm", ".appimage", ".flatpak"},
			os:       models.OSLinux,
		},
		{
			patterns: []string{"mac", "darwin"},
			suffixes: []string{".dmg", ".pkg"},
			os:       models.OSMacOS,
		},
		{
			patterns: []string{"freebsd"},
			os:       models.OSFreeBSD,
		},
		{
			patterns: []string{"openbsd"},
			os:       models.OSOpenBSD,
		},
		{
			patterns: []string{"android"},
			suffixes: []string{".apk"},
			os:       models.OSAndroid,
		},
		{
			patterns: []string{"arm", "aarch64"},
			os:       models.OSARM,
		},
	}

	for _, entry := range osMap {
		for _, p := range entry.patterns {
			if strings.Contains(lower, p) {
				return entry.os
			}
		}
		for _, s := range entry.suffixes {
			if strings.HasSuffix(lower, s) {
				return entry.os
			}
		}
	}

	return models.OSUnknown
}

func FetchRepoInfo(server, token, owner, repo string) (string, []string, string, bool, string, error) {
	url := fmt.Sprintf("%s%s/%s/%s", server, RepoAPIPath, owner, repo)
	req, err := http.NewRequest("GET", url, nil)
	if err != nil {
		return "", nil, "", false, "", err
	}

	if token != "" {
		req.Header.Set("Authorization", "token "+token)
	}

	client := &http.Client{Timeout: DefaultTimeout}
	resp, err := client.Do(req)
	if err != nil {
		return "", nil, "", false, "", err
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return "", nil, "", false, "", fmt.Errorf("gitea api returned status %d", resp.StatusCode)
	}

	var info struct {
		Description   string   `json:"description"`
		Topics        []string `json:"topics"`
		DefaultBranch string   `json:"default_branch"`
		Licenses      []string `json:"licenses"`
		Private       bool     `json:"private"`
		AvatarURL     string   `json:"avatar_url"`
	}
	if err := json.NewDecoder(resp.Body).Decode(&info); err != nil {
		return "", nil, "", false, "", err
	}

	license := ""
	if len(info.Licenses) > 0 {
		license = info.Licenses[0]
	}
	if license == "" {
		// Try to detect license from file if API returns nothing
		license = detectLicenseFromFile(server, token, owner, repo, info.DefaultBranch)
	}

	return info.Description, info.Topics, license, info.Private, info.AvatarURL, nil
}

func detectLicenseFromFile(server, token, owner, repo, defaultBranch string) string {
	branches := []string{"main", "master"}
	if defaultBranch != "" {
		branches = append([]string{defaultBranch}, "main", "master")
	}
	seen := make(map[string]bool)
	var finalBranches []string
	for _, b := range branches {
		if !seen[b] {
			seen[b] = true
			finalBranches = append(finalBranches, b)
		}
	}

	for _, branch := range finalBranches {
		url := fmt.Sprintf("%s/%s/%s/raw/branch/%s/LICENSE", server, owner, repo, branch)
		req, err := http.NewRequest("GET", url, nil)
		if err != nil {
			continue
		}
		if token != "" {
			req.Header.Set("Authorization", "token "+token)
		}

		client := &http.Client{Timeout: DefaultTimeout}
		resp, err := client.Do(req)
		if err != nil {
			continue
		}
		defer resp.Body.Close()

		if resp.StatusCode == http.StatusOK {
			scanner := bufio.NewScanner(resp.Body)
			for i := 0; i < 5 && scanner.Scan(); i++ {
				line := strings.ToUpper(scanner.Text())
				if strings.Contains(line, "MIT LICENSE") {
					return "MIT"
				}
				if strings.Contains(line, "GNU GENERAL PUBLIC LICENSE") || strings.Contains(line, "GPL") {
					return "GPL"
				}
				if strings.Contains(line, "APACHE LICENSE") {
					return "Apache-2.0"
				}
				if strings.Contains(line, "BSD") {
					return "BSD"
				}
			}
			return "LICENSE"
		}
	}
	return ""
}

func IsSBOM(filename string) bool {
	lower := strings.ToLower(filename)
	return strings.Contains(lower, "sbom") ||
		strings.Contains(lower, "cyclonedx") ||
		strings.Contains(lower, "spdx") ||
		strings.HasSuffix(lower, ".cdx.json") ||
		strings.HasSuffix(lower, ".spdx.json")
}

func FetchReleases(server, token, owner, repo string) ([]models.Release, error) {
	url := fmt.Sprintf("%s%s/%s/%s%s", server, RepoAPIPath, owner, repo, ReleasesSuffix)
	req, err := http.NewRequest("GET", url, nil)
	if err != nil {
		return nil, err
	}

	if token != "" {
		req.Header.Set("Authorization", "token "+token)
	}

	client := &http.Client{Timeout: DefaultTimeout}
	resp, err := client.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("gitea api returned status %d", resp.StatusCode)
	}

	var giteaReleases []struct {
		TagName   string    `json:"tag_name"`
		Body      string    `json:"body"`
		CreatedAt time.Time `json:"created_at"`
		Assets    []struct {
			Name string `json:"name"`
			Size int64  `json:"size"`
			URL  string `json:"browser_download_url"`
		} `json:"assets"`
	}

	if err := json.NewDecoder(resp.Body).Decode(&giteaReleases); err != nil {
		return nil, err
	}

	contributors, _ := FetchContributors(server, token, owner, repo)
	security := CheckSourceSecurity(server, token, owner, repo)

	var releases []models.Release
	for _, gr := range giteaReleases {
		var assets []models.Asset
		var checksumsURL string

		for _, ga := range gr.Assets {
			if ga.Name == "SHA256SUMS" {
				checksumsURL = ga.URL
				continue
			}
			assets = append(assets, models.Asset{
				Name:   ga.Name,
				Size:   ga.Size,
				URL:    ga.URL,
				OS:     DetectOS(ga.Name),
				IsSBOM: IsSBOM(ga.Name),
			})
		}

		if checksumsURL != "" {
			checksums, err := fetchAndParseChecksums(checksumsURL, token)
			if err == nil {
				for i := range assets {
					if sha, ok := checksums[assets[i].Name]; ok {
						assets[i].SHA256 = sha
					}
				}
			}
		}

		releases = append(releases, models.Release{
			TagName:      gr.TagName,
			Body:         gr.Body,
			CreatedAt:    gr.CreatedAt,
			Assets:       assets,
			Contributors: contributors,
			Security:     security,
		})
	}

	return releases, nil
}

func fetchAndParseChecksums(url, token string) (map[string]string, error) {
	req, err := http.NewRequest("GET", url, nil)
	if err != nil {
		return nil, err
	}
	if token != "" {
		req.Header.Set("Authorization", "token "+token)
	}

	client := &http.Client{Timeout: DefaultTimeout}
	resp, err := client.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("failed to fetch checksums: %d", resp.StatusCode)
	}

	checksums := make(map[string]string)
	scanner := bufio.NewScanner(resp.Body)
	for scanner.Scan() {
		line := strings.TrimSpace(scanner.Text())
		if line == "" {
			continue
		}
		parts := strings.Fields(line)
		if len(parts) >= 2 {
			checksums[parts[1]] = parts[0]
		}
	}
	return checksums, nil
}