// Filename: internal/repository/key_cache.go
package repository

import (
	"encoding/json"
	"fmt"
	"gemini-balancer/internal/models"
	"strconv"
)

const (
	KeyGroup               = "group:%d:keys:active"
	KeyDetails             = "key:%d:details"
	KeyMapping             = "mapping:%d:%d"
	KeyGroupSequential     = "group:%d:keys:sequential"
	KeyGroupLRU            = "group:%d:keys:lru"
	KeyGroupRandomMain     = "group:%d:keys:random:main"
	KeyGroupRandomCooldown = "group:%d:keys:random:cooldown"
	BasePoolSequential     = "basepool:%s:keys:sequential"
	BasePoolLRU            = "basepool:%s:keys:lru"
	BasePoolRandomMain     = "basepool:%s:keys:random:main"
	BasePoolRandomCooldown = "basepool:%s:keys:random:cooldown"
)

func (r *gormKeyRepository) LoadAllKeysToStore() error {
	r.logger.Info("Starting to load all keys and associations into cache, including polling structures...")
	var allMappings []*models.GroupAPIKeyMapping
	if err := r.db.Preload("APIKey").Find(&allMappings).Error; err != nil {
		return fmt.Errorf("failed to load all mappings with APIKeys from DB: %w", err)
	}

	keyMap := make(map[uint]*models.APIKey)
	for _, m := range allMappings {
		if m.APIKey != nil {
			keyMap[m.APIKey.ID] = m.APIKey
		}
	}
	keysToDecrypt := make([]models.APIKey, 0, len(keyMap))
	for _, k := range keyMap {
		keysToDecrypt = append(keysToDecrypt, *k)
	}
	if err := r.decryptKeys(keysToDecrypt); err != nil {
		r.logger.WithError(err).Error("Critical error during cache preload: batch decryption failed.")
	}
	decryptedKeyMap := make(map[uint]models.APIKey)
	for _, k := range keysToDecrypt {
		decryptedKeyMap[k.ID] = k
	}

	activeKeysByGroup := make(map[uint][]*models.GroupAPIKeyMapping)
	pipe := r.store.Pipeline()
	detailsToSet := make(map[string][]byte)
	var allGroups []*models.KeyGroup
	if err := r.db.Find(&allGroups).Error; err == nil {
		for _, group := range allGroups {
			pipe.Del(
				fmt.Sprintf(KeyGroup, group.ID),
				fmt.Sprintf(KeyGroupSequential, group.ID),
				fmt.Sprintf(KeyGroupLRU, group.ID),
				fmt.Sprintf(KeyGroupRandomMain, group.ID),
				fmt.Sprintf(KeyGroupRandomCooldown, group.ID),
			)
		}
	} else {
		r.logger.WithError(err).Error("Failed to get all groups for cache cleanup")
	}

	for _, mapping := range allMappings {
		if mapping.APIKey == nil {
			continue
		}
		decryptedKey, ok := decryptedKeyMap[mapping.APIKeyID]
		if !ok {
			continue
		}
		keyJSON, _ := json.Marshal(decryptedKey)
		detailsToSet[fmt.Sprintf(KeyDetails, decryptedKey.ID)] = keyJSON
		mappingJSON, _ := json.Marshal(mapping)
		detailsToSet[fmt.Sprintf(KeyMapping, mapping.KeyGroupID, decryptedKey.ID)] = mappingJSON
		if mapping.Status == models.StatusActive {
			activeKeysByGroup[mapping.KeyGroupID] = append(activeKeysByGroup[mapping.KeyGroupID], mapping)
		}
	}

	for groupID, activeMappings := range activeKeysByGroup {
		if len(activeMappings) == 0 {
			continue
		}
		var activeKeyIDs []interface{}
		lruMembers := make(map[string]float64)
		for _, mapping := range activeMappings {
			keyIDStr := strconv.FormatUint(uint64(mapping.APIKeyID), 10)
			activeKeyIDs = append(activeKeyIDs, keyIDStr)
			var score float64
			if mapping.LastUsedAt != nil {
				score = float64(mapping.LastUsedAt.UnixMilli())
			}
			lruMembers[keyIDStr] = score
		}
		pipe.SAdd(fmt.Sprintf(KeyGroup, groupID), activeKeyIDs...)
		pipe.LPush(fmt.Sprintf(KeyGroupSequential, groupID), activeKeyIDs...)
		pipe.SAdd(fmt.Sprintf(KeyGroupRandomMain, groupID), activeKeyIDs...)
		go r.store.ZAdd(fmt.Sprintf(KeyGroupLRU, groupID), lruMembers)
	}

	if err := pipe.Exec(); err != nil {
		return fmt.Errorf("failed to execute pipeline for cache rebuild: %w", err)
	}
	for key, value := range detailsToSet {
		if err := r.store.Set(key, value, 0); err != nil {
			r.logger.WithError(err).Warnf("Failed to set key detail in cache: %s", key)
		}
	}

	r.logger.Info("Cache rebuild complete, including all polling structures.")
	return nil
}

func (r *gormKeyRepository) updateStoreCacheForKey(key *models.APIKey) error {
	if err := r.decryptKey(key); err != nil {
		return fmt.Errorf("failed to decrypt key %d for cache update: %w", key.ID, err)
	}
	keyJSON, err := json.Marshal(key)
	if err != nil {
		return fmt.Errorf("failed to marshal key %d for cache update: %w", key.ID, err)
	}
	return r.store.Set(fmt.Sprintf(KeyDetails, key.ID), keyJSON, 0)
}

func (r *gormKeyRepository) removeStoreCacheForKey(key *models.APIKey) error {
	groupIDs, err := r.GetGroupsForKey(key.ID)
	if err != nil {
		r.logger.Warnf("failed to get groups for key %d to clean up cache lists: %v", key.ID, err)
	}

	pipe := r.store.Pipeline()
	pipe.Del(fmt.Sprintf(KeyDetails, key.ID))

	for _, groupID := range groupIDs {
		pipe.Del(fmt.Sprintf(KeyMapping, groupID, key.ID))

		keyIDStr := strconv.FormatUint(uint64(key.ID), 10)
		pipe.SRem(fmt.Sprintf(KeyGroup, groupID), keyIDStr)
		pipe.LRem(fmt.Sprintf(KeyGroupSequential, groupID), 0, keyIDStr)
		pipe.SRem(fmt.Sprintf(KeyGroupRandomMain, groupID), keyIDStr)
		pipe.SRem(fmt.Sprintf(KeyGroupRandomCooldown, groupID), keyIDStr)
		go r.store.ZRem(fmt.Sprintf(KeyGroupLRU, groupID), keyIDStr)
	}
	return pipe.Exec()
}

func (r *gormKeyRepository) updateStoreCacheForMapping(mapping *models.GroupAPIKeyMapping) error {
	pipe := r.store.Pipeline()
	activeKeyListKey := fmt.Sprintf("group:%d:keys:active", mapping.KeyGroupID)
	pipe.LRem(activeKeyListKey, 0, mapping.APIKeyID)
	if mapping.Status == models.StatusActive {
		pipe.LPush(activeKeyListKey, mapping.APIKeyID)
	}
	return pipe.Exec()
}

func (r *gormKeyRepository) HandleCacheUpdateEventBatch(mappings []*models.GroupAPIKeyMapping) error {
	if len(mappings) == 0 {
		return nil
	}
	groupUpdates := make(map[uint]struct {
		ToAdd    []interface{}
		ToRemove []interface{}
	})
	for _, mapping := range mappings {
		keyIDStr := strconv.FormatUint(uint64(mapping.APIKeyID), 10)
		update, ok := groupUpdates[mapping.KeyGroupID]
		if !ok {
			update = struct {
				ToAdd    []interface{}
				ToRemove []interface{}
			}{}
		}
		if mapping.Status == models.StatusActive {
			update.ToRemove = append(update.ToRemove, keyIDStr)
			update.ToAdd = append(update.ToAdd, keyIDStr)
		} else {
			update.ToRemove = append(update.ToRemove, keyIDStr)
		}
		groupUpdates[mapping.KeyGroupID] = update
	}
	pipe := r.store.Pipeline()
	var pipelineError error
	for groupID, updates := range groupUpdates {
		activeKeyListKey := fmt.Sprintf("group:%d:keys:active", groupID)
		if len(updates.ToRemove) > 0 {
			for _, keyID := range updates.ToRemove {
				pipe.LRem(activeKeyListKey, 0, keyID)
			}
		}
		if len(updates.ToAdd) > 0 {
			pipe.LPush(activeKeyListKey, updates.ToAdd...)
		}
	}
	if err := pipe.Exec(); err != nil {
		pipelineError = fmt.Errorf("redis pipeline execution failed: %w", err)
	}
	return pipelineError
}