package model

import (
	"fmt"
	"sort"
	"strings"
	"sync"
	"time"

	"github.com/QuantumNous/new-api/common"
	"github.com/QuantumNous/new-api/constant"
	"github.com/QuantumNous/new-api/setting/ratio_setting"
)

var group2model2channels map[string]map[string][]int // enabled channel
var channelsIDM map[int]*Channel                     // all channels include disabled
var channelSyncLock sync.RWMutex

func InitChannelCache() {
	if !common.MemoryCacheEnabled {
		return
	}
	newChannelId2channel := make(map[int]*Channel)
	var channels []*Channel
	DB.Find(&channels)
	for _, channel := range channels {
		newChannelId2channel[channel.Id] = channel
	}
	var abilities []*Ability
	DB.Find(&abilities)
	groups := make(map[string]bool)
	for _, ability := range abilities {
		groups[ability.Group] = true
	}
	newGroup2model2channels := make(map[string]map[string][]int)
	for group := range groups {
		newGroup2model2channels[group] = make(map[string][]int)
	}
	for _, channel := range channels {
		if channel.Status != common.ChannelStatusEnabled {
			continue // skip disabled channels
		}
		groups := strings.Split(channel.Group, ",")
		for _, group := range groups {
			models := strings.Split(channel.Models, ",")
			for _, model := range models {
				if _, ok := newGroup2model2channels[group][model]; !ok {
					newGroup2model2channels[group][model] = make([]int, 0)
				}
				newGroup2model2channels[group][model] = append(newGroup2model2channels[group][model], channel.Id)
			}
		}
	}

	// sort by priority
	for group, model2channels := range newGroup2model2channels {
		for model, channels := range model2channels {
			sort.Slice(channels, func(i, j int) bool {
				return newChannelId2channel[channels[i]].GetPriority() > newChannelId2channel[channels[j]].GetPriority()
			})
			newGroup2model2channels[group][model] = channels
		}
	}

	channelSyncLock.Lock()
	group2model2channels = newGroup2model2channels
	//channelsIDM = newChannelId2channel
	for i, channel := range newChannelId2channel {
		if channel.ChannelInfo.IsMultiKey {
			channel.Keys = channel.GetKeys()
			if channel.ChannelInfo.MultiKeyMode == constant.MultiKeyModePolling {
				if oldChannel, ok := channelsIDM[i]; ok {
					// 存在旧的渠道，如果是多key且轮询，保留轮询索引信息
					if oldChannel.ChannelInfo.IsMultiKey && oldChannel.ChannelInfo.MultiKeyMode == constant.MultiKeyModePolling {
						channel.ChannelInfo.MultiKeyPollingIndex = oldChannel.ChannelInfo.MultiKeyPollingIndex
					}
				}
			}
		}
	}
	channelsIDM = newChannelId2channel
	channelSyncLock.Unlock()
	common.SysLog("channels synced from database")
}

func SyncChannelCache(frequency int) {
	for {
		time.Sleep(time.Duration(frequency) * time.Second)
		common.SysLog("syncing channels from database")
		InitChannelCache()
	}
}

func GetRandomSatisfiedChannel(group string, model string, retry int) (*Channel, error) {
	// if memory cache is disabled, get channel directly from database
	if !common.MemoryCacheEnabled {
		return GetChannel(group, model, retry)
	}

	channelSyncLock.RLock()
	defer channelSyncLock.RUnlock()

	// First, try to find channels with the exact model name.
	channels := group2model2channels[group][model]

	// If no channels found, try to find channels with the normalized model name.
	if len(channels) == 0 {
		normalizedModel := ratio_setting.FormatMatchingModelName(model)
		channels = group2model2channels[group][normalizedModel]
	}

	if len(channels) == 0 {
		return nil, nil
	}

	uniquePriorities := make(map[int]bool)
	for _, channelId := range channels {
		if channel, ok := channelsIDM[channelId]; ok {
			uniquePriorities[int(channel.GetPriority())] = true
		} else {
			return nil, fmt.Errorf("数据库一致性错误，渠道# %d 不存在，请联系管理员修复", channelId)
		}
	}
	var sortedUniquePriorities []int
	for priority := range uniquePriorities {
		sortedUniquePriorities = append(sortedUniquePriorities, priority)
	}
	sort.Sort(sort.Reverse(sort.IntSlice(sortedUniquePriorities)))

	if len(sortedUniquePriorities) == 0 {
		return nil, nil
	}
	if retry < 0 {
		retry = 0
	}
	if retry >= len(channels) {
		retry = len(channels) - 1
	}

	orderedChannels := make([]*Channel, 0, len(channels))
	for _, priority := range sortedUniquePriorities {
		targetPriority := int64(priority)
		targetChannels := make([]*Channel, 0)
		for _, channelId := range channels {
			channel, ok := channelsIDM[channelId]
			if !ok {
				return nil, fmt.Errorf("数据库一致性错误，渠道# %d 不存在，请联系管理员修复", channelId)
			}
			if channel.GetPriority() == targetPriority {
				targetChannels = append(targetChannels, channel)
			}
		}
		sort.SliceStable(targetChannels, func(i, j int) bool {
			left := targetChannels[i]
			right := targetChannels[j]
			if left.GetWeight() != right.GetWeight() {
				return left.GetWeight() > right.GetWeight()
			}
			if left.GetPriority() != right.GetPriority() {
				return left.GetPriority() > right.GetPriority()
			}
			return left.Id < right.Id
		})
		orderedChannels = append(orderedChannels, targetChannels...)
	}

	if len(orderedChannels) == 0 {
		return nil, nil
	}
	if retry >= len(orderedChannels) {
		retry = len(orderedChannels) - 1
	}
	return orderedChannels[retry], nil
}

func CacheGetChannel(id int) (*Channel, error) {
	if !common.MemoryCacheEnabled {
		return GetChannelById(id, true)
	}
	channelSyncLock.RLock()
	defer channelSyncLock.RUnlock()

	c, ok := channelsIDM[id]
	if !ok {
		return nil, fmt.Errorf("渠道# %d，已不存在", id)
	}
	return c, nil
}

func CacheGetChannelInfo(id int) (*ChannelInfo, error) {
	if !common.MemoryCacheEnabled {
		channel, err := GetChannelById(id, true)
		if err != nil {
			return nil, err
		}
		return &channel.ChannelInfo, nil
	}
	channelSyncLock.RLock()
	defer channelSyncLock.RUnlock()

	c, ok := channelsIDM[id]
	if !ok {
		return nil, fmt.Errorf("渠道# %d，已不存在", id)
	}
	return &c.ChannelInfo, nil
}

func CacheUpdateChannelStatus(id int, status int) {
	if !common.MemoryCacheEnabled {
		return
	}
	channelSyncLock.Lock()
	defer channelSyncLock.Unlock()
	if channel, ok := channelsIDM[id]; ok {
		channel.Status = status
	}
	if status != common.ChannelStatusEnabled {
		// delete the channel from group2model2channels
		for group, model2channels := range group2model2channels {
			for model, channels := range model2channels {
				for i, channelId := range channels {
					if channelId == id {
						// remove the channel from the slice
						group2model2channels[group][model] = append(channels[:i], channels[i+1:]...)
						break
					}
				}
			}
		}
	}
}

func CacheUpdateChannel(channel *Channel) {
	if !common.MemoryCacheEnabled {
		return
	}
	channelSyncLock.Lock()
	defer channelSyncLock.Unlock()
	if channel == nil {
		return
	}

	println("CacheUpdateChannel:", channel.Id, channel.Name, channel.Status, channel.ChannelInfo.MultiKeyPollingIndex)

	println("before:", channelsIDM[channel.Id].ChannelInfo.MultiKeyPollingIndex)
	channelsIDM[channel.Id] = channel
	println("after :", channelsIDM[channel.Id].ChannelInfo.MultiKeyPollingIndex)
}