// Package database define database operation functions
package database

import (
	"context"
	"fmt"

	"modelRT/constants"
	"modelRT/model"
	"modelRT/sql"

	"gorm.io/gorm"
)

type parameterInitializationRoute struct {
	TableName      string `gorm:"column:name"`
	ModelName      string `gorm:"column:tag"`
	AttributeGroup string `gorm:"column:group_name"`
}

// QueryParameterInitializationRecords loads every parameter accepted by the
// data-object query API. Dynamic parameters are resolved through
// project_manager; component parameters are read directly from component.
func QueryParameterInitializationRecords(ctx context.Context, db *gorm.DB) ([]model.ParameterInitializationRecord, error) {
	if db == nil {
		return nil, fmt.Errorf("postgres client is nil")
	}

	var routes []parameterInitializationRoute
	if err := db.WithContext(ctx).
		Raw(
			compactParameterSQL(sql.ParameterInitializationRoutes),
			constants.SupportedDynamicParameterAttributeGroups(),
		).
		Scan(&routes).Error; err != nil {
		return nil, fmt.Errorf("query parameter initialization routes: %w", err)
	}
	if err := validateParameterInitializationRoutes(routes); err != nil {
		return nil, err
	}

	records := make([]model.ParameterInitializationRecord, 0)
	for _, route := range routes {
		quotedTableName := `"` + route.TableName + `"`
		query := compactParameterSQL(
			fmt.Sprintf(sql.DynamicParameterInitializationRows, quotedTableName),
		)

		var tableRecords []model.ParameterInitializationRecord
		if err := db.WithContext(ctx).
			Raw(query, route.TableName, route.ModelName, route.AttributeGroup).
			Scan(&tableRecords).Error; err != nil {
			return nil, fmt.Errorf(
				"query parameter initialization table %q for model %q group %q: %w",
				route.TableName,
				route.ModelName,
				route.AttributeGroup,
				err,
			)
		}
		if err := validateParameterInitializationRecords(tableRecords); err != nil {
			return nil, fmt.Errorf("validate parameter initialization table %q: %w", route.TableName, err)
		}
		records = append(records, tableRecords...)
	}

	var componentRecords []model.ParameterInitializationRecord
	if err := db.WithContext(ctx).
		Raw(compactParameterSQL(sql.ComponentParameterInitializationRows)).
		Scan(&componentRecords).Error; err != nil {
		return nil, fmt.Errorf("query component parameter initialization records: %w", err)
	}
	if err := validateParameterInitializationRecords(componentRecords); err != nil {
		return nil, fmt.Errorf("validate component parameter initialization records: %w", err)
	}
	records = append(records, componentRecords...)
	return records, nil
}

func validateParameterInitializationRoutes(routes []parameterInitializationRoute) error {
	seen := make(map[string]struct{}, len(routes))
	for _, route := range routes {
		if !validParameterTableName(route.TableName) {
			return fmt.Errorf("project_manager contains unsupported parameter table name %q", route.TableName)
		}
		if !constants.IsSupportedParameterAttributeGroup(route.AttributeGroup) ||
			route.AttributeGroup == constants.ComponentParameterAttributeGroup {
			return fmt.Errorf("project_manager contains unsupported dynamic attribute group %q", route.AttributeGroup)
		}

		key := route.ModelName + "\x00" + route.AttributeGroup
		if _, exists := seen[key]; exists {
			return fmt.Errorf(
				"model %q and attribute group %q match more than one project_manager record",
				route.ModelName,
				route.AttributeGroup,
			)
		}
		seen[key] = struct{}{}
	}
	return nil
}

func validateParameterInitializationRecords(records []model.ParameterInitializationRecord) error {
	for _, record := range records {
		switch record.DynamicRecordCount {
		case 1:
		case 0:
			return fmt.Errorf(
				"component %q has no %q parameter record",
				record.ComponentTag,
				record.AttributeGroup,
			)
		default:
			return fmt.Errorf(
				"component %q has %d %q parameter records",
				record.ComponentTag,
				record.DynamicRecordCount,
				record.AttributeGroup,
			)
		}
		if record.AttributeName == "" || record.AttributeType == "" {
			return fmt.Errorf(
				"component %q group %q contains an invalid parameter column",
				record.ComponentTag,
				record.AttributeGroup,
			)
		}
		switch record.DescriptionCount {
		case 0:
			return fmt.Errorf("parameter description not found for attribute %q", record.AttributeName)
		case 1:
			if !record.Description.Valid {
				return fmt.Errorf("parameter description is null for attribute %q", record.AttributeName)
			}
		default:
			return fmt.Errorf("ambiguous parameter description for attribute %q", record.AttributeName)
		}
	}
	return nil
}