package tgcore

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io"
	"net"
	"net/http"
	"strings"
	"time"
)

var API string

func Init(token string) {
	API = "https://api.telegram.org/bot" + token
}

func TG(method string, body interface{}) (map[string]interface{}, error) {
	jsonBody, err := json.Marshal(body)
	if err != nil {
		return nil, err
	}
	resp, err := http.Post(API+"/"+method, "application/json", bytes.NewReader(jsonBody))
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	data, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}
	var result map[string]interface{}
	if err := json.Unmarshal(data, &result); err != nil {
		return nil, err
	}
	return result, nil
}

func Allowed(chatID int64, allowedIDs []int64) bool {
	if len(allowedIDs) == 0 {
		return true
	}
	for _, id := range allowedIDs {
		if id == chatID {
			return true
		}
	}
	return false
}

func SendMessage(chatID int64, text string, opts map[string]interface{}) error {
	safeText := text
	body := map[string]interface{}{
		"chat_id":                  chatID,
		"text":                     safeText,
		"parse_mode":               "HTML",
		"disable_web_page_preview": true,
	}
	if opts != nil {
		for k, v := range opts {
			body[k] = v
		}
	}

	_, err := TG("sendMessage", body)
	if err != nil && (strings.Contains(err.Error(), "parse") || strings.Contains(err.Error(), "HTML")) {
		delete(body, "parse_mode")
		_, err = TG("sendMessage", body)
	}
	return err
}

// TgHandler is the callback handler interface
type TgHandler interface {
	List(chatID int64, page string)
	Links(chatID int64, page string)
	Feeds(chatID int64, page string)
	// Session callbacks
	SessionCallback(chatID int64, action string)
	MenuCallback(chatID int64, action string)
}

func HandleCallback(chatID int64, queryID string, data string, h TgHandler) {
	if data == "" {
		return
	}

	// Session callbacks
	if strings.HasPrefix(data, "session_") {
		action := strings.TrimPrefix(data, "session_")
		if h != nil {
			h.SessionCallback(chatID, action)
		}
		TG("answerCallbackQuery", map[string]interface{}{"callback_query_id": queryID})
		return
	}

	// Menu callbacks
	if strings.HasPrefix(data, "menu_") {
		action := strings.TrimPrefix(data, "menu_")
		if h != nil {
			h.MenuCallback(chatID, action)
		}
		TG("answerCallbackQuery", map[string]interface{}{"callback_query_id": queryID})
		return
	}

	// Pagination callbacks: list_N, links_N, feeds_N
	parts := strings.SplitN(data, "_", 2)
	if len(parts) == 2 {
		cmd := parts[0]
		page := parts[1]
		if h != nil {
			switch cmd {
			case "list":
				h.List(chatID, page)
			case "links":
				h.Links(chatID, page)
			case "feeds":
				h.Feeds(chatID, page)
			}
		}
	}
	TG("answerCallbackQuery", map[string]interface{}{"callback_query_id": queryID})
}

func GetInt64(m map[string]interface{}, key string) int64 {
	if v, ok := m[key]; ok {
		switch n := v.(type) {
		case float64:
			return int64(n)
		case int64:
			return n
		}
	}
	return 0
}

func GetString(m map[string]interface{}, key string) string {
	if v, ok := m[key]; ok {
		if s, ok := v.(string); ok {
			return s
		}
	}
	return ""
}

// === Inlined from helpers ===

var lanIPCache struct {
	ip string
	ts time.Time
}

func GetLanIP(preferIface string) string {
	if lanIPCache.ip != "" && time.Since(lanIPCache.ts) < 30*time.Second {
		return lanIPCache.ip
	}

	ip := "0.0.0.0"
	ifaces, err := net.Interfaces()
	if err != nil {
		lanIPCache.ip = ip
		lanIPCache.ts = time.Now()
		return ip
	}

	type candidate struct {
		name    string
		address string
	}
	var candidates []candidate

	for _, iface := range ifaces {
		addrs, err := iface.Addrs()
		if err != nil {
			continue
		}
		for _, addr := range addrs {
			ipNet, ok := addr.(*net.IPNet)
			if !ok {
				continue
			}
			ip4 := ipNet.IP.To4()
			if ip4 == nil {
				continue
			}
			if ip4.IsLoopback() {
				continue
			}
			ipStr := ip4.String()
			if strings.HasPrefix(ipStr, "169.254.") {
				continue
			}
			candidates = append(candidates, candidate{name: iface.Name, address: ipStr})
		}
	}

	prefLower := strings.ToLower(preferIface)
	for _, c := range candidates {
		if strings.Contains(strings.ToLower(c.name), prefLower) {
			ip = c.address
			lanIPCache.ip = ip
			lanIPCache.ts = time.Now()
			return ip
		}
	}

	for _, c := range candidates {
		n := strings.ToLower(c.name)
		if !strings.Contains(n, "vmware") && !strings.Contains(n, "virtual") && !strings.Contains(n, "vethernet") {
			ip = c.address
			lanIPCache.ip = ip
			lanIPCache.ts = time.Now()
			return ip
		}
	}

	if len(candidates) > 0 {
		ip = candidates[0].address
	}

	lanIPCache.ip = ip
	lanIPCache.ts = time.Now()
	return ip
}

func CheckPort(port int) bool {
	conn, err := net.DialTimeout("tcp", fmt.Sprintf("127.0.0.1:%d", port), 1500*time.Millisecond)
	if err != nil {
		return false
	}
	conn.Close()
	return true
}

func WaitForReady(port int, timeoutMs int) bool {
	if timeoutMs <= 0 {
		timeoutMs = 30000
	}
	deadline := time.Now().Add(time.Duration(timeoutMs) * time.Millisecond)
	for time.Now().Before(deadline) {
		if CheckPort(port) {
			return true
		}
		time.Sleep(1500 * time.Millisecond)
	}
	return false
}

func MakeSlug(title string) string {
	dateStr := time.Now().Format("2006-01-02")
	slugPart := title
	// Replace non-word, non-CJK chars with -
	slugPart = strings.Map(func(r rune) rune {
		if (r >= 0x4e00 && r <= 0x9fff) || (r >= 'a' && r <= 'z') || (r >= 'A' && r <= 'Z') || (r >= '0' && r <= '9') || r == '-' {
			return r
		}
		return '-'
	}, slugPart)
	slugPart = strings.Trim(slugPart, "-")
	slugPart = strings.ToLower(slugPart)
	if slugPart == "" {
		slugPart = "post"
	}
	return dateStr + "-" + slugPart
}

func SessionSummary(title string, categories, tags []string, content string) string {
	lines := 0
	chars := len([]rune(content))
	for _, ch := range content {
		if ch == '\n' {
			lines++
		}
	}
	if content != "" {
		lines++
	}

	displayTitle := title
	if displayTitle == "" {
		displayTitle = "未命名"
	}

	parts := []string{
		fmt.Sprintf("📝 <b>%s</b>", displayTitle),
	}
	if len(categories) > 0 {
		parts = append(parts, "📂 "+strings.Join(categories, "、"))
	}
	if len(tags) > 0 {
		parts = append(parts, "🏷 "+strings.Join(tags, "、"))
	}
	if chars > 0 {
		parts = append(parts, fmt.Sprintf("✍ %d 行 %d 字", lines, chars))
	}
	return strings.Join(parts, "  ·  ")
}