package controller

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

	"ezops/model"

	"gorm.io/gorm"
)

// dispatchCategoryAlert 按告警集合策略发送告警通知 // Logan.Li
func dispatchCategoryAlert(db *gorm.DB, category string, ruleName, hostname, metric, severity, message string, value, threshold float64) {
	var policy model.AlertNotifyPolicy
	if err := db.Where("category = ? AND enabled = ?", category, true).First(&policy).Error; err != nil {
		fallbackNotifyChannels(db, ruleName, hostname, metric, severity, message, value, threshold)
		return
	}
	title := buildNotifyTitle(db, ruleName, hostname, metric, severity)
	content := buildAlertContent(ruleName, hostname, metric, severity, message, value, threshold)
	sent, _ := dispatchToPolicyContacts(db, &policy, title, content, severity, false)
	if sent == 0 {
		fallbackNotifyChannels(db, ruleName, hostname, metric, severity, message, value, threshold)
	}
}

// dispatchCategoryRecovery 按告警集合策略发送恢复通知 // Logan.Li
func dispatchCategoryRecovery(db *gorm.DB, category, ruleName, hostname, metric, message string) {
	var policy model.AlertNotifyPolicy
	if err := db.Where("category = ? AND enabled = ?", category, true).First(&policy).Error; err != nil {
		fallbackNotifyRecovery(db, ruleName, hostname, metric, message)
		return
	}
	title := fmt.Sprintf("%s — 已恢复正常", ruleName)
	content := fmt.Sprintf("**告警已恢复**\\n\\n目标：%s\\n指标：%s\\n详情：%s\\n恢复时间：%s",
		hostname, metric, message, time.Now().Format("2006-01-02 15:04:05"))
	sent, _ := dispatchToPolicyContacts(db, &policy, title, content, "info", true)
	if sent == 0 {
		fallbackNotifyRecovery(db, ruleName, hostname, metric, message)
	}
}

// resolvePolicyContactIDs 展开策略中的联系组与直接联系人 // Logan.Li
func resolvePolicyContactIDs(db *gorm.DB, policy *model.AlertNotifyPolicy) []uint {
	idSet := make(map[uint]struct{})

	var groupIDs []uint
	if policy.ContactGroupIDs != "" && policy.ContactGroupIDs != "null" {
		_ = json.Unmarshal([]byte(policy.ContactGroupIDs), &groupIDs)
	}
	for _, gid := range groupIDs {
		var g model.AlertContactGroup
		if db.First(&g, gid).Error != nil {
			continue
		}
		var cids []uint
		if g.ContactIDs != "" && g.ContactIDs != "null" {
			_ = json.Unmarshal([]byte(g.ContactIDs), &cids)
		}
		for _, cid := range cids {
			idSet[cid] = struct{}{}
		}
	}

	var directIDs []uint
	if policy.ContactIDs != "" && policy.ContactIDs != "null" {
		_ = json.Unmarshal([]byte(policy.ContactIDs), &directIDs)
	}
	for _, cid := range directIDs {
		idSet[cid] = struct{}{}
	}

	ids := make([]uint, 0, len(idSet))
	for id := range idSet {
		ids = append(ids, id)
	}
	return ids
}

// dispatchToPolicyContacts 向策略解析出的联系人发送通知 // Logan.Li
func dispatchToPolicyContacts(db *gorm.DB, policy *model.AlertNotifyPolicy, title, content, severity string, isRecovery bool) (sent, skipped int) {
	if policy == nil || !policy.Enabled {
		return 0, 1
	}
	contactIDs := resolvePolicyContactIDs(db, policy)
	if len(contactIDs) == 0 {
		return 0, 1
	}

	for _, cid := range contactIDs {
		var contact model.AlertContact
		if db.First(&contact, cid).Error != nil || contact.WebhookURL == "" {
			skipped++
			continue
		}
		var err error
		switch contact.ChannelType {
		case "feishu", "":
			if isRecovery {
				err = sendFeishuRecovery(db, feishuConfigFromURL(contact.WebhookURL), title, content)
			} else {
				err = sendFeishuAlert(db, feishuConfigFromURL(contact.WebhookURL), title, content, severity)
			}
		case "dingtalk", "wechat", "webhook":
			err = sendGenericWebhook(contact.WebhookURL, title, content)
		default:
			err = sendGenericWebhook(contact.WebhookURL, title, content)
		}
		if err != nil {
			fmt.Printf("[AlertNotify] 通知失败 (联系人:%s): %v\n", contact.Name, err)
			skipped++
		} else {
			sent++
		}
	}
	return sent, skipped
}

// feishuConfigFromURL 联系人 webhook 转飞书配置 JSON // Logan.Li
func feishuConfigFromURL(url string) string {
	b, _ := json.Marshal(model.FeishuWebhookConfig{URL: url})
	return string(b)
}

// sendGenericWebhook 钉钉/企微/通用 Webhook 文本通知 // Logan.Li
func sendGenericWebhook(webhookURL, title, content string) error {
	body := map[string]interface{}{
		"msgtype": "text",
		"text": map[string]string{
			"content": title + "\n" + strings.ReplaceAll(content, "\\n", "\n"),
		},
	}
	raw, _ := json.Marshal(body)
	req, err := http.NewRequest("POST", webhookURL, bytes.NewReader(raw))
	if err != nil {
		return err
	}
	req.Header.Set("Content-Type", "application/json")
	client := &http.Client{Timeout: 10 * time.Second}
	resp, err := client.Do(req)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusOK {
		b, _ := io.ReadAll(resp.Body)
		return fmt.Errorf("HTTP %d: %s", resp.StatusCode, string(b))
	}
	return nil
}

// fallbackNotifyChannels 无策略时回退到全局 NotifyChannel // Logan.Li
func fallbackNotifyChannels(db *gorm.DB, ruleName, hostname, metric, severity, message string, value, threshold float64) {
	var channels []model.NotifyChannel
	db.Where("enabled = ? AND type = ?", true, "feishu").Find(&channels)
	title := buildNotifyTitle(db, ruleName, hostname, metric, severity)
	content := buildAlertContent(ruleName, hostname, metric, severity, message, value, threshold)
	for _, ch := range channels {
		if err := sendFeishuAlert(db, ch.Config, title, content, severity); err != nil {
			fmt.Printf("[AlertNotify] 飞书回退通知失败 (渠道:%s): %v\n", ch.Name, err)
		}
	}
}

func fallbackNotifyRecovery(db *gorm.DB, ruleName, hostname, metric, message string) {
	var channels []model.NotifyChannel
	db.Where("enabled = ? AND type = ?", true, "feishu").Find(&channels)
	title := fmt.Sprintf("%s — 已恢复正常", ruleName)
	content := fmt.Sprintf("**告警已恢复**\\n\\n主机：%s\\n指标：%s\\n详情：%s\\n恢复时间：%s",
		hostname, metric, message, time.Now().Format("2006-01-02 15:04:05"))
	for _, ch := range channels {
		if err := sendFeishuRecovery(db, ch.Config, title, content); err != nil {
			fmt.Printf("[AlertNotify] 飞书恢复回退失败 (渠道:%s): %v\n", ch.Name, err)
		}
	}
}