package migrations

import (
	"fmt"
	"strings"

	"github.com/grafana/grafana/pkg/services/sqlstore/migrator"
	"github.com/grafana/grafana/pkg/setting"
)

func getKeyColumn(name string, isPrimaryKey bool) *migrator.Column {
	return &migrator.Column{
		Name:         name,
		Type:         migrator.DB_NVarchar,
		Length:       1024,
		Nullable:     false,
		IsPrimaryKey: isPrimaryKey,
		IsLatin:      true, // only used in MySQL
	}
}

func addObjectStorageMigrations(mg *migrator.Migrator) {
	tables := []migrator.Table{}
	tables = append(tables, migrator.Table{
		Name: "object",
		Columns: []*migrator.Column{
			// Object path contains everything required to make it unique across all instances
			// orgId + scope + kind + uid
			getKeyColumn("path", true),

			// This is an optimization for listing everything at the same level in the object store
			getKeyColumn("parent_folder_path", false),

			// The object type
			{Name: "kind", Type: migrator.DB_NVarchar, Length: 255, Nullable: false},

			// The raw object body (any byte array)
			{Name: "body", Type: migrator.DB_LongBlob, Nullable: false},
			{Name: "size", Type: migrator.DB_BigInt, Nullable: false},
			{Name: "etag", Type: migrator.DB_NVarchar, Length: 32, Nullable: false, IsLatin: true}, // md5(body)
			{Name: "version", Type: migrator.DB_NVarchar, Length: 128, Nullable: false},

			// Who changed what when -- We should avoid JOINs with other tables in the database
			{Name: "updated_at", Type: migrator.DB_BigInt, Nullable: false},
			{Name: "created_at", Type: migrator.DB_BigInt, Nullable: false},
			{Name: "updated_by", Type: migrator.DB_NVarchar, Length: 190, Nullable: false},
			{Name: "created_by", Type: migrator.DB_NVarchar, Length: 190, Nullable: false},

			// For objects that are synchronized from an external source (ie provisioning or git)
			{Name: "sync_src", Type: migrator.DB_Text, Nullable: true},
			{Name: "sync_time", Type: migrator.DB_BigInt, Nullable: true},

			// Summary data (always extracted from the `body` column)
			{Name: "name", Type: migrator.DB_NVarchar, Length: 255, Nullable: false},
			{Name: "description", Type: migrator.DB_NVarchar, Length: 255, Nullable: true},
			{Name: "labels", Type: migrator.DB_Text, Nullable: true}, // JSON object
			{Name: "fields", Type: migrator.DB_Text, Nullable: true}, // JSON object
			{Name: "errors", Type: migrator.DB_Text, Nullable: true}, // JSON object
		},
		Indices: []*migrator.Index{
			{Cols: []string{"parent_folder_path"}}, // list in folder
			{Cols: []string{"kind"}},               // filter by type
		},
	})

	tables = append(tables, migrator.Table{
		Name: "object_labels",
		Columns: []*migrator.Column{
			getKeyColumn("path", false),
			{Name: "label", Type: migrator.DB_NVarchar, Length: 191, Nullable: false},
			{Name: "value", Type: migrator.DB_NVarchar, Length: 1024, Nullable: false},
		},
		Indices: []*migrator.Index{
			{Cols: []string{"path", "label"}, Type: migrator.UniqueIndex},
		},
	})

	tables = append(tables, migrator.Table{
		Name: "object_ref",
		Columns: []*migrator.Column{
			// Source:
			getKeyColumn("path", false),

			// Address (defined in the body, not resolved, may be invalid and change)
			{Name: "kind", Type: migrator.DB_NVarchar, Length: 255, Nullable: false},
			{Name: "type", Type: migrator.DB_NVarchar, Length: 255, Nullable: true},
			{Name: "uid", Type: migrator.DB_NVarchar, Length: 1024, Nullable: true},

			// Runtime calcs (will depend on the system state)
			{Name: "resolved_ok", Type: migrator.DB_Bool, Nullable: false},
			getKeyColumn("resolved_to", false),
			{Name: "resolved_warning", Type: migrator.DB_NVarchar, Length: 255, Nullable: false},
			{Name: "resolved_time", Type: migrator.DB_DateTime, Nullable: false}, // resolution cache timestamp
		},
		Indices: []*migrator.Index{
			{Cols: []string{"path"}, Type: migrator.IndexType},
			{Cols: []string{"kind"}, Type: migrator.IndexType},
			{Cols: []string{"resolved_to"}, Type: migrator.IndexType},
		},
	})

	tables = append(tables, migrator.Table{
		Name: "object_history",
		Columns: []*migrator.Column{
			getKeyColumn("path", false),
			{Name: "version", Type: migrator.DB_NVarchar, Length: 128, Nullable: false},

			// Raw bytes
			{Name: "body", Type: migrator.DB_LongBlob, Nullable: false},
			{Name: "size", Type: migrator.DB_BigInt, Nullable: false},
			{Name: "etag", Type: migrator.DB_NVarchar, Length: 32, Nullable: false, IsLatin: true}, // md5(body)

			// Who changed what when
			{Name: "updated_at", Type: migrator.DB_BigInt, Nullable: false},
			{Name: "updated_by", Type: migrator.DB_NVarchar, Length: 190, Nullable: false},

			// Commit message
			{Name: "message", Type: migrator.DB_Text, Nullable: false}, // defaults to empty string
		},
		Indices: []*migrator.Index{
			{Cols: []string{"path", "version"}, Type: migrator.UniqueIndex},
			{Cols: []string{"updated_by"}, Type: migrator.IndexType},
		},
	})

	// !!! This should not run in production!
	// The object store SQL schema is still in active development and this
	// will only be called when the feature toggle is enabled
	// this check should not be necessary, but is added as an extra check
	if setting.Env == setting.Prod {
		return
	}

	// Migration cleanups: given that this is a complex setup
	// that requires a lot of testing before we are ready to push out of dev
	// this script lets us easy wipe previous changes and initialize clean tables
	suffix := " (v2)" // change this when we want to wipe and reset the object tables
	mg.AddMigration("ObjectStore init: cleanup"+suffix, migrator.NewRawSQLMigration(strings.TrimSpace(`
		DELETE FROM migration_log WHERE migration_id LIKE 'ObjectStore init%';
	`)))

	// Initialize all tables
	for t := range tables {
		mg.AddMigration("ObjectStore init: drop "+tables[t].Name+suffix, migrator.NewRawSQLMigration(
			fmt.Sprintf("DROP TABLE IF EXISTS %s", tables[t].Name),
		))
		mg.AddMigration("ObjectStore init: table "+tables[t].Name+suffix, migrator.NewAddTableMigration(tables[t]))
		for i := range tables[t].Indices {
			mg.AddMigration(fmt.Sprintf("ObjectStore init: index %s[%d]"+suffix, tables[t].Name, i), migrator.NewAddIndexMigration(tables[t], tables[t].Indices[i]))
		}
	}

	// TODO: add collation support to `migrator.Column`
	mg.AddMigration("ObjectStore init: set path collation in object tables"+suffix, migrator.NewRawSQLMigration("").
		// MySQL `utf8mb4_unicode_ci` collation is set in `mysql_dialect.go`
		// SQLite uses a `BINARY` collation by default
		Postgres("ALTER TABLE object ALTER COLUMN path TYPE VARCHAR(1024) COLLATE \"C\";")) // Collate C - sorting done based on character code byte values
}