package database

import (
	"context"
	"trbot/database/db_struct"
	"trbot/database/redis_db"
	"trbot/database/yaml_db"
	"trbot/utils"

	"github.com/go-telegram/bot/models"
	"github.com/rs/zerolog"
)

type DatabaseBackend struct {
	// 数据库名称
	Name string

	// 数据库等级，低优先级的数据库不会实时同步更改，程序仅会在高优先级数据库不可用才会尝试使用其中的数据
	IsLowLevel bool

	// 数据库初始化函数
	Initializer func(ctx context.Context) error

	// 数据库保存和读取函数
	SaveDatabase func(ctx context.Context) error
	ReadDatabase func(ctx context.Context) error

	// 操作数据库的函数
	InitUser              func(ctx context.Context, user *models.User) error
	InitChat              func(ctx context.Context, chat *models.Chat) error
	GetChatInfo           func(ctx context.Context, id int64) (*db_struct.ChatInfo, error)
	IncrementalUsageCount func(ctx context.Context, chatID int64, fieldName db_struct.ChatInfoField_UsageCount) error
	RecordLatestData      func(ctx context.Context, chatID int64, fieldName db_struct.ChatInfoField_LatestData, value string) error
	UpdateOperationStatus func(ctx context.Context, chatID int64, fieldName db_struct.ChatInfoField_Status, value bool) error
	SetCustomFlag         func(ctx context.Context, chatID int64, fieldName db_struct.ChatInfoField_CustomFlag, value string) error
}

var DBBackends []DatabaseBackend
var DBBackends_LowLevel []DatabaseBackend

func AddDatabaseBackends(ctx context.Context, backends ...DatabaseBackend) int {
	logger := zerolog.Ctx(ctx)

	if DBBackends == nil { DBBackends = []DatabaseBackend{} }
	if DBBackends_LowLevel == nil { DBBackends_LowLevel = []DatabaseBackend{} }

	var count int
	for _, db := range backends {
		err := db.Initializer(ctx)
		if err != nil {
			logger.Error().
				Err(err).
				Str("database", db.Name).
				Msg("Failed to initialize database")
		} else {
 			if db.IsLowLevel {
				DBBackends_LowLevel = append(DBBackends_LowLevel, db)
			} else {
				DBBackends = append(DBBackends, db)
			}
			logger.Info().
				Str("database", db.Name).
				Str("databaseLevel", utils.TextForTrueOrFalse(db.IsLowLevel, "low", "high")).
				Msg("Database initialized")
			count++
		}
	}

	return count
}

func InitAndListDatabases(ctx context.Context) {
	// redis
	AddDatabaseBackends(ctx, DatabaseBackend{
		Name:        "redis",
		Initializer: redis_db.InitializeDB,

		InitUser:              redis_db.InitUser,
		InitChat:              redis_db.InitChat,
		GetChatInfo:           redis_db.GetChatInfo,
		IncrementalUsageCount: redis_db.IncrementalUsageCount,
		RecordLatestData:      redis_db.RecordLatestData,
		UpdateOperationStatus: redis_db.UpdateOperationStatus,
		SetCustomFlag:         redis_db.SetCustomFlag,
	})
	// yaml
	AddDatabaseBackends(ctx, DatabaseBackend{
		Name:        "yaml",
		IsLowLevel:  true,
		Initializer: yaml_db.InitializeDB,

		SaveDatabase: yaml_db.SaveDatabase,
		ReadDatabase: yaml_db.ReadDatabase,

		InitUser:              yaml_db.InitUser,
		InitChat:              yaml_db.InitChat,
		GetChatInfo:           yaml_db.GetChatInfo,
		IncrementalUsageCount: yaml_db.IncrementalUsageCount,
		RecordLatestData:      yaml_db.RecordLatestData,
		UpdateOperationStatus: yaml_db.UpdateOperationStatus,
		SetCustomFlag:         yaml_db.SetCustomFlag,
	})

	if len(DBBackends) + len(DBBackends_LowLevel) == 0 {
		zerolog.Ctx(ctx).Fatal().
			Msg("No database available")
	}

	zerolog.Ctx(ctx).Info().
		Int("highLevel", len(DBBackends)).
		Int("lowLevel", len(DBBackends_LowLevel)).
		Msg("Available databases")
}