package sync

import (
	"GoNavi-Wails/internal/connection"
	"GoNavi-Wails/internal/db"
	"fmt"
	"strings"
)

type genericLegacyPlanner struct{}

type mysqlToPGLikePlanner struct{}

type mysqlToClickHousePlanner struct{}

type pgLikeToClickHousePlanner struct{}

type clickHouseToMySQLPlanner struct{}

type clickHouseToPGLikePlanner struct{}

type mysqlToMongoPlanner struct{}

type pgLikeToMongoPlanner struct{}

type clickHouseToMongoPlanner struct{}

type tdengineToMongoPlanner struct{}

type mongoToMySQLPlanner struct{}

type mongoToPGLikePlanner struct{}

type pgLikeToMySQLPlanner struct{}

type tdengineToMySQLPlanner struct{}

type tdengineToPGLikePlanner struct{}

type mongoToRelationalPlanner struct{}

func buildSchemaMigrationPlan(config SyncConfig, tableName string, sourceDB db.Database, targetDB db.Database) (SchemaMigrationPlan, []connection.ColumnDefinition, []connection.ColumnDefinition, error) {
	ctx := MigrationBuildContext{
		Config:    config,
		TableName: tableName,
		SourceDB:  sourceDB,
		TargetDB:  targetDB,
	}
	planner := resolveMigrationPlanner(ctx)
	if planner == nil {
		return buildSchemaMigrationPlanLegacy(config, tableName, sourceDB, targetDB)
	}
	return planner.BuildPlan(ctx)
}

func resolveMigrationPlanner(ctx MigrationBuildContext) MigrationPlanner {
	planners := []MigrationPlanner{
		mysqlToPGLikePlanner{},
		mySQLLikeToTDenginePlanner{},
		pgLikeToTDenginePlanner{},
		clickHouseToTDenginePlanner{},
		tdengineToTDenginePlanner{},
		tdengineToPGLikePlanner{},
		tdengineToMySQLPlanner{},
		mysqlToClickHousePlanner{},
		pgLikeToClickHousePlanner{},
		clickHouseToMySQLPlanner{},
		clickHouseToPGLikePlanner{},
		mysqlToMongoPlanner{},
		pgLikeToMongoPlanner{},
		clickHouseToMongoPlanner{},
		tdengineToMongoPlanner{},
		mongoToMySQLPlanner{},
		mongoToPGLikePlanner{},
		pgLikeToMySQLPlanner{},
		mongoToRelationalPlanner{},
		genericLegacyPlanner{},
	}
	bestLevel := MigrationSupportLevelUnsupported
	var bestPlanner MigrationPlanner
	for _, planner := range planners {
		level := planner.SupportLevel(ctx)
		if migrationSupportRank(level) > migrationSupportRank(bestLevel) {
			bestLevel = level
			bestPlanner = planner
		}
	}
	return bestPlanner
}

func migrationSupportRank(level MigrationSupportLevel) int {
	switch level {
	case MigrationSupportLevelFull:
		return 4
	case MigrationSupportLevelPlanned:
		return 3
	case MigrationSupportLevelPartial:
		return 2
	default:
		return 1
	}
}

func isMySQLLikeType(dbType string) bool {
	return isMySQLLikeWritableTargetType(dbType)
}

func classifyMigrationDataModel(dbType string) MigrationDataModel {
	switch normalizeMigrationDBType(dbType) {
	case "mysql", "mariadb", "oceanbase", "postgres", "kingbase", "highgo", "vastbase", "opengauss", "oracle", "sqlserver", "dameng", "sqlite", "duckdb":
		return MigrationDataModelRelational
	case "mongodb":
		return MigrationDataModelDocument
	case "clickhouse", "diros", "sphinx":
		return MigrationDataModelColumnar
	case "tdengine":
		return MigrationDataModelTimeSeries
	case "redis":
		return MigrationDataModelKeyValue
	default:
		return MigrationDataModelCustom
	}
}

func (genericLegacyPlanner) Name() string { return "generic-legacy-planner" }

func (genericLegacyPlanner) SupportLevel(ctx MigrationBuildContext) MigrationSupportLevel {
	_ = ctx
	return MigrationSupportLevelPartial
}

func (genericLegacyPlanner) BuildPlan(ctx MigrationBuildContext) (SchemaMigrationPlan, []connection.ColumnDefinition, []connection.ColumnDefinition, error) {
	return buildSchemaMigrationPlanLegacy(ctx.Config, ctx.TableName, ctx.SourceDB, ctx.TargetDB)
}

func (mysqlToPGLikePlanner) Name() string { return "mysql-pglike-planner" }

func (mysqlToPGLikePlanner) SupportLevel(ctx MigrationBuildContext) MigrationSupportLevel {
	sourceType := resolveMigrationDBType(ctx.Config.SourceConfig)
	targetType := resolveMigrationDBType(ctx.Config.TargetConfig)
	if isMySQLLikeSourceType(sourceType) && isPGLikeTarget(targetType) {
		return MigrationSupportLevelFull
	}
	return MigrationSupportLevelUnsupported
}

func (mysqlToPGLikePlanner) BuildPlan(ctx MigrationBuildContext) (SchemaMigrationPlan, []connection.ColumnDefinition, []connection.ColumnDefinition, error) {
	return buildMySQLToPGLikePlan(ctx.Config, ctx.TableName, ctx.SourceDB, ctx.TargetDB)
}

func (tdengineToMySQLPlanner) Name() string { return "tdengine-mysql-planner" }

func (tdengineToMySQLPlanner) SupportLevel(ctx MigrationBuildContext) MigrationSupportLevel {
	sourceType := resolveMigrationDBType(ctx.Config.SourceConfig)
	targetType := resolveMigrationDBType(ctx.Config.TargetConfig)
	if sourceType == "tdengine" && isMySQLLikeWritableTargetType(targetType) {
		return MigrationSupportLevelFull
	}
	return MigrationSupportLevelUnsupported
}

func (tdengineToMySQLPlanner) BuildPlan(ctx MigrationBuildContext) (SchemaMigrationPlan, []connection.ColumnDefinition, []connection.ColumnDefinition, error) {
	return buildTDengineToMySQLPlan(ctx.Config, ctx.TableName, ctx.SourceDB, ctx.TargetDB)
}

func (tdengineToPGLikePlanner) Name() string { return "tdengine-pglike-planner" }

func (tdengineToPGLikePlanner) SupportLevel(ctx MigrationBuildContext) MigrationSupportLevel {
	sourceType := resolveMigrationDBType(ctx.Config.SourceConfig)
	targetType := resolveMigrationDBType(ctx.Config.TargetConfig)
	if sourceType == "tdengine" && isPGLikeTarget(targetType) {
		return MigrationSupportLevelFull
	}
	return MigrationSupportLevelUnsupported
}

func (tdengineToPGLikePlanner) BuildPlan(ctx MigrationBuildContext) (SchemaMigrationPlan, []connection.ColumnDefinition, []connection.ColumnDefinition, error) {
	return buildTDengineToPGLikePlan(ctx.Config, ctx.TableName, ctx.SourceDB, ctx.TargetDB)
}

func (mysqlToClickHousePlanner) Name() string { return "mysql-clickhouse-planner" }

func (mysqlToClickHousePlanner) SupportLevel(ctx MigrationBuildContext) MigrationSupportLevel {
	sourceType := resolveMigrationDBType(ctx.Config.SourceConfig)
	targetType := resolveMigrationDBType(ctx.Config.TargetConfig)
	if isMySQLCoreType(sourceType) && targetType == "clickhouse" {
		return MigrationSupportLevelFull
	}
	return MigrationSupportLevelUnsupported
}

func (mysqlToClickHousePlanner) BuildPlan(ctx MigrationBuildContext) (SchemaMigrationPlan, []connection.ColumnDefinition, []connection.ColumnDefinition, error) {
	return buildMySQLToClickHousePlan(ctx.Config, ctx.TableName, ctx.SourceDB, ctx.TargetDB)
}

func (pgLikeToClickHousePlanner) Name() string { return "pglike-clickhouse-planner" }

func (pgLikeToClickHousePlanner) SupportLevel(ctx MigrationBuildContext) MigrationSupportLevel {
	sourceType := resolveMigrationDBType(ctx.Config.SourceConfig)
	targetType := resolveMigrationDBType(ctx.Config.TargetConfig)
	if isPGLikeSource(sourceType) && targetType == "clickhouse" {
		return MigrationSupportLevelFull
	}
	return MigrationSupportLevelUnsupported
}

func (pgLikeToClickHousePlanner) BuildPlan(ctx MigrationBuildContext) (SchemaMigrationPlan, []connection.ColumnDefinition, []connection.ColumnDefinition, error) {
	return buildPGLikeToClickHousePlan(ctx.Config, ctx.TableName, ctx.SourceDB, ctx.TargetDB)
}

func (clickHouseToMySQLPlanner) Name() string { return "clickhouse-mysql-planner" }

func (clickHouseToMySQLPlanner) SupportLevel(ctx MigrationBuildContext) MigrationSupportLevel {
	sourceType := resolveMigrationDBType(ctx.Config.SourceConfig)
	targetType := resolveMigrationDBType(ctx.Config.TargetConfig)
	if sourceType == "clickhouse" && isMySQLLikeWritableTargetType(targetType) {
		return MigrationSupportLevelFull
	}
	return MigrationSupportLevelUnsupported
}

func (clickHouseToMySQLPlanner) BuildPlan(ctx MigrationBuildContext) (SchemaMigrationPlan, []connection.ColumnDefinition, []connection.ColumnDefinition, error) {
	return buildClickHouseToMySQLPlan(ctx.Config, ctx.TableName, ctx.SourceDB, ctx.TargetDB)
}

func (clickHouseToPGLikePlanner) Name() string { return "clickhouse-pglike-planner" }

func (clickHouseToPGLikePlanner) SupportLevel(ctx MigrationBuildContext) MigrationSupportLevel {
	sourceType := resolveMigrationDBType(ctx.Config.SourceConfig)
	targetType := resolveMigrationDBType(ctx.Config.TargetConfig)
	if sourceType == "clickhouse" && isPGLikeTarget(targetType) {
		return MigrationSupportLevelFull
	}
	return MigrationSupportLevelUnsupported
}

func (clickHouseToPGLikePlanner) BuildPlan(ctx MigrationBuildContext) (SchemaMigrationPlan, []connection.ColumnDefinition, []connection.ColumnDefinition, error) {
	return buildClickHouseToPGLikePlan(ctx.Config, ctx.TableName, ctx.SourceDB, ctx.TargetDB)
}

func (mysqlToMongoPlanner) Name() string { return "mysql-mongo-planner" }

func (mysqlToMongoPlanner) SupportLevel(ctx MigrationBuildContext) MigrationSupportLevel {
	sourceType := resolveMigrationDBType(ctx.Config.SourceConfig)
	targetType := resolveMigrationDBType(ctx.Config.TargetConfig)
	if isMySQLCoreType(sourceType) && targetType == "mongodb" {
		return MigrationSupportLevelFull
	}
	return MigrationSupportLevelUnsupported
}

func (mysqlToMongoPlanner) BuildPlan(ctx MigrationBuildContext) (SchemaMigrationPlan, []connection.ColumnDefinition, []connection.ColumnDefinition, error) {
	return buildMySQLToMongoPlan(ctx.Config, ctx.TableName, ctx.SourceDB, ctx.TargetDB)
}

func (pgLikeToMongoPlanner) Name() string { return "pglike-mongo-planner" }

func (pgLikeToMongoPlanner) SupportLevel(ctx MigrationBuildContext) MigrationSupportLevel {
	sourceType := resolveMigrationDBType(ctx.Config.SourceConfig)
	targetType := resolveMigrationDBType(ctx.Config.TargetConfig)
	if isPGLikeSource(sourceType) && targetType == "mongodb" {
		return MigrationSupportLevelFull
	}
	return MigrationSupportLevelUnsupported
}

func (pgLikeToMongoPlanner) BuildPlan(ctx MigrationBuildContext) (SchemaMigrationPlan, []connection.ColumnDefinition, []connection.ColumnDefinition, error) {
	return buildPGLikeToMongoPlan(ctx.Config, ctx.TableName, ctx.SourceDB, ctx.TargetDB)
}

func (clickHouseToMongoPlanner) Name() string { return "clickhouse-mongo-planner" }

func (clickHouseToMongoPlanner) SupportLevel(ctx MigrationBuildContext) MigrationSupportLevel {
	sourceType := resolveMigrationDBType(ctx.Config.SourceConfig)
	targetType := resolveMigrationDBType(ctx.Config.TargetConfig)
	if sourceType == "clickhouse" && targetType == "mongodb" {
		return MigrationSupportLevelFull
	}
	return MigrationSupportLevelUnsupported
}

func (clickHouseToMongoPlanner) BuildPlan(ctx MigrationBuildContext) (SchemaMigrationPlan, []connection.ColumnDefinition, []connection.ColumnDefinition, error) {
	return buildClickHouseToMongoPlan(ctx.Config, ctx.TableName, ctx.SourceDB, ctx.TargetDB)
}

func (tdengineToMongoPlanner) Name() string { return "tdengine-mongo-planner" }

func (tdengineToMongoPlanner) SupportLevel(ctx MigrationBuildContext) MigrationSupportLevel {
	sourceType := resolveMigrationDBType(ctx.Config.SourceConfig)
	targetType := resolveMigrationDBType(ctx.Config.TargetConfig)
	if sourceType == "tdengine" && targetType == "mongodb" {
		return MigrationSupportLevelFull
	}
	return MigrationSupportLevelUnsupported
}

func (tdengineToMongoPlanner) BuildPlan(ctx MigrationBuildContext) (SchemaMigrationPlan, []connection.ColumnDefinition, []connection.ColumnDefinition, error) {
	return buildTDengineToMongoPlan(ctx.Config, ctx.TableName, ctx.SourceDB, ctx.TargetDB)
}

func (mongoToMySQLPlanner) Name() string { return "mongo-mysql-planner" }

func (mongoToMySQLPlanner) SupportLevel(ctx MigrationBuildContext) MigrationSupportLevel {
	sourceType := resolveMigrationDBType(ctx.Config.SourceConfig)
	targetType := resolveMigrationDBType(ctx.Config.TargetConfig)
	if sourceType == "mongodb" && isMySQLLikeWritableTargetType(targetType) {
		return MigrationSupportLevelFull
	}
	return MigrationSupportLevelUnsupported
}

func (mongoToMySQLPlanner) BuildPlan(ctx MigrationBuildContext) (SchemaMigrationPlan, []connection.ColumnDefinition, []connection.ColumnDefinition, error) {
	return buildMongoToMySQLPlan(ctx.Config, ctx.TableName, ctx.SourceDB, ctx.TargetDB)
}

func (mongoToPGLikePlanner) Name() string { return "mongo-pglike-planner" }

func (mongoToPGLikePlanner) SupportLevel(ctx MigrationBuildContext) MigrationSupportLevel {
	sourceType := resolveMigrationDBType(ctx.Config.SourceConfig)
	targetType := resolveMigrationDBType(ctx.Config.TargetConfig)
	if sourceType == "mongodb" && isPGLikeTarget(targetType) {
		return MigrationSupportLevelFull
	}
	return MigrationSupportLevelUnsupported
}

func (mongoToPGLikePlanner) BuildPlan(ctx MigrationBuildContext) (SchemaMigrationPlan, []connection.ColumnDefinition, []connection.ColumnDefinition, error) {
	return buildMongoToPGLikePlan(ctx.Config, ctx.TableName, ctx.SourceDB, ctx.TargetDB)
}

func (pgLikeToMySQLPlanner) Name() string { return "pglike-mysql-planner" }

func (pgLikeToMySQLPlanner) SupportLevel(ctx MigrationBuildContext) MigrationSupportLevel {
	sourceType := resolveMigrationDBType(ctx.Config.SourceConfig)
	targetType := resolveMigrationDBType(ctx.Config.TargetConfig)
	if isPGLikeSource(sourceType) && isMySQLLikeWritableTargetType(targetType) {
		return MigrationSupportLevelFull
	}
	return MigrationSupportLevelUnsupported
}

func (pgLikeToMySQLPlanner) BuildPlan(ctx MigrationBuildContext) (SchemaMigrationPlan, []connection.ColumnDefinition, []connection.ColumnDefinition, error) {
	return buildPGLikeToMySQLPlan(ctx.Config, ctx.TableName, ctx.SourceDB, ctx.TargetDB)
}

func (mongoToRelationalPlanner) Name() string { return "mongo-relational-inference-planner" }

func (mongoToRelationalPlanner) SupportLevel(ctx MigrationBuildContext) MigrationSupportLevel {
	sourceType := resolveMigrationDBType(ctx.Config.SourceConfig)
	targetType := resolveMigrationDBType(ctx.Config.TargetConfig)
	if !shouldUseSchemaInference(sourceType, targetType) {
		return MigrationSupportLevelUnsupported
	}
	return MigrationSupportLevelPlanned
}

func (mongoToRelationalPlanner) BuildPlan(ctx MigrationBuildContext) (SchemaMigrationPlan, []connection.ColumnDefinition, []connection.ColumnDefinition, error) {
	sourceType := resolveMigrationDBType(ctx.Config.SourceConfig)
	targetType := resolveMigrationDBType(ctx.Config.TargetConfig)
	inference, err := inferSchemaForPair(sourceType, targetType, ctx.TableName)
	if err != nil {
		return SchemaMigrationPlan{}, nil, nil, err
	}
	plan := SchemaMigrationPlan{}
	plan.SourceSchema, plan.SourceTable = normalizeSchemaAndTable(sourceType, ctx.Config.SourceConfig.Database, ctx.TableName)
	plan.TargetSchema, plan.TargetTable = normalizeSchemaAndTable(targetType, ctx.Config.TargetConfig.Database, ctx.TableName)
	plan.SourceQueryTable = qualifiedNameForQuery(sourceType, plan.SourceSchema, plan.SourceTable, ctx.TableName)
	plan.TargetQueryTable = qualifiedNameForQuery(targetType, plan.TargetSchema, plan.TargetTable, ctx.TableName)
	plan.PlannedAction = "当前库对已进入迁移内核规划阶段，等待 schema 推断与目标方言生成器落地"
	for _, issue := range inference.Issues {
		msg := strings.TrimSpace(issue.Message)
		if msg == "" {
			continue
		}
		plan.Warnings = append(plan.Warnings, msg)
	}
	plan.Warnings = append(plan.Warnings, fmt.Sprintf("迁移对象=%s，目标类型=%s，当前仅提供规划入口，暂不执行自动建表", inference.Object.Kind, targetType))
	return dedupeSchemaMigrationPlan(plan), nil, nil, nil
}