package pq

import (
	"database/sql/driver"
	"fmt"
	"io"
	"net"
	"net/url"
	"regexp"
	"runtime"
	"strings"
)

// Error severities
const (
	Efatal   = "FATAL"
	Epanic   = "PANIC"
	Ewarning = "WARNING"
	Enotice  = "NOTICE"
	Edebug   = "DEBUG"
	Einfo    = "INFO"
	Elog     = "LOG"
)

// Error represents an error communicating with the server.
//
// See http://www.postgresql.org/docs/current/static/protocol-error-fields.html for details of the fields
type Error struct {
	Severity         string
	Code             ErrorCode
	Message          string
	Detail           string
	Hint             string
	Position         string
	InternalPosition string
	InternalQuery    string
	Where            string
	Schema           string
	Table            string
	Column           string
	DataTypeName     string
	Constraint       string
	File             string
	Line             string
	Routine          string
}

// ErrorCode is a five-character error code.
type ErrorCode string

// Name returns a more human friendly rendering of the error code, namely the
// "condition name".
//
// See http://www.postgresql.org/docs/9.3/static/errcodes-appendix.html for
// details.
func (ec ErrorCode) Name() string {
	return errorCodeNames[ec]
}

func (ec ErrorCode) String() string {
	return string(ec)
}

// ErrorClass is only the class part of an error code.
type ErrorClass string

// Name returns the condition name of an error class.  It is equivalent to the
// condition name of the "standard" error code (i.e. the one having the last
// three characters "000").
func (ec ErrorClass) Name() string {
	return errorCodeNames[ErrorCode(ec+"000")]
}

// Class returns the error class, e.g. "28".
//
// See http://www.postgresql.org/docs/9.3/static/errcodes-appendix.html for
// details.
func (ec ErrorCode) Class() ErrorClass {
	return ErrorClass(ec[0:2])
}

// errorCodeNames is a mapping between the five-character error codes and the
// human readable "condition names". It is derived from the list at
// http://www.postgresql.org/docs/9.3/static/errcodes-appendix.html
var errorCodeNames = map[ErrorCode]string{
	// Class 00 - Successful Completion
	"00000": "successful_completion",
	// Class 01 - Warning
	"01000": "warning",
	"0100C": "dynamic_result_sets_returned",
	"01008": "implicit_zero_bit_padding",
	"01003": "null_value_eliminated_in_set_function",
	"01007": "privilege_not_granted",
	"01006": "privilege_not_revoked",
	"01004": "string_data_right_truncation",
	"01P01": "deprecated_feature",
	// Class 02 - No Data (this is also a warning class per the SQL standard)
	"02000": "no_data",
	"02001": "no_additional_dynamic_result_sets_returned",
	// Class 03 - SQL Statement Not Yet Complete
	"03000": "sql_statement_not_yet_complete",
	// Class 08 - Connection Exception
	"08000": "connection_exception",
	"08003": "connection_does_not_exist",
	"08006": "connection_failure",
	"08001": "sqlclient_unable_to_establish_sqlconnection",
	"08004": "sqlserver_rejected_establishment_of_sqlconnection",
	"08007": "transaction_resolution_unknown",
	"08P01": "protocol_violation",
	// Class 09 - Triggered Action Exception
	"09000": "triggered_action_exception",
	// Class 0A - Feature Not Supported
	"0A000": "feature_not_supported",
	// Class 0B - Invalid Transaction Initiation
	"0B000": "invalid_transaction_initiation",
	// Class 0F - Locator Exception
	"0F000": "locator_exception",
	"0F001": "invalid_locator_specification",
	// Class 0L - Invalid Grantor
	"0L000": "invalid_grantor",
	"0LP01": "invalid_grant_operation",
	// Class 0P - Invalid Role Specification
	"0P000": "invalid_role_specification",
	// Class 0Z - Diagnostics Exception
	"0Z000": "diagnostics_exception",
	"0Z002": "stacked_diagnostics_accessed_without_active_handler",
	// Class 20 - Case Not Found
	"20000": "case_not_found",
	// Class 21 - Cardinality Violation
	"21000": "cardinality_violation",
	// Class 22 - Data Exception
	"22000": "data_exception",
	"2202E": "array_subscript_error",
	"22021": "character_not_in_repertoire",
	"22008": "datetime_field_overflow",
	"22012": "division_by_zero",
	"22005": "error_in_assignment",
	"2200B": "escape_character_conflict",
	"22022": "indicator_overflow",
	"22015": "interval_field_overflow",
	"2201E": "invalid_argument_for_logarithm",
	"22014": "invalid_argument_for_ntile_function",
	"22016": "invalid_argument_for_nth_value_function",
	"2201F": "invalid_argument_for_power_function",
	"2201G": "invalid_argument_for_width_bucket_function",
	"22018": "invalid_character_value_for_cast",
	"22007": "invalid_datetime_format",
	"22019": "invalid_escape_character",
	"2200D": "invalid_escape_octet",
	"22025": "invalid_escape_sequence",
	"22P06": "nonstandard_use_of_escape_character",
	"22010": "invalid_indicator_parameter_value",
	"22023": "invalid_parameter_value",
	"2201B": "invalid_regular_expression",
	"2201W": "invalid_row_count_in_limit_clause",
	"2201X": "invalid_row_count_in_result_offset_clause",
	"22009": "invalid_time_zone_displacement_value",
	"2200C": "invalid_use_of_escape_character",
	"2200G": "most_specific_type_mismatch",
	"22004": "null_value_not_allowed",
	"22002": "null_value_no_indicator_parameter",
	"22003": "numeric_value_out_of_range",
	"2200H": "sequence_generator_limit_exceeded",
	"22026": "string_data_length_mismatch",
	"22001": "string_data_right_truncation",
	"22011": "substring_error",
	"22027": "trim_error",
	"22024": "unterminated_c_string",
	"2200F": "zero_length_character_string",
	"22P01": "floating_point_exception",
	"22P02": "invalid_text_representation",
	"22P03": "invalid_binary_representation",
	"22P04": "bad_copy_file_format",
	"22P05": "untranslatable_character",
	"2200L": "not_an_xml_document",
	"2200M": "invalid_xml_document",
	"2200N": "invalid_xml_content",
	"2200S": "invalid_xml_comment",
	"2200T": "invalid_xml_processing_instruction",
	// Class 23 - Integrity Constraint Violation
	"23000": "integrity_constraint_violation",
	"23001": "restrict_violation",
	"23502": "not_null_violation",
	"23503": "foreign_key_violation",
	"23505": "unique_violation",
	"23514": "check_violation",
	"23P01": "exclusion_violation",
	// Class 24 - Invalid Cursor State
	"24000": "invalid_cursor_state",
	// Class 25 - Invalid Transaction State
	"25000": "invalid_transaction_state",
	"25001": "active_sql_transaction",
	"25002": "branch_transaction_already_active",
	"25008": "held_cursor_requires_same_isolation_level",
	"25003": "inappropriate_access_mode_for_branch_transaction",
	"25004": "inappropriate_isolation_level_for_branch_transaction",
	"25005": "no_active_sql_transaction_for_branch_transaction",
	"25006": "read_only_sql_transaction",
	"25007": "schema_and_data_statement_mixing_not_supported",
	"25P01": "no_active_sql_transaction",
	"25P02": "in_failed_sql_transaction",
	// Class 26 - Invalid SQL Statement Name
	"26000": "invalid_sql_statement_name",
	// Class 27 - Triggered Data Change Violation
	"27000": "triggered_data_change_violation",
	// Class 28 - Invalid Authorization Specification
	"28000": "invalid_authorization_specification",
	"28P01": "invalid_password",
	// Class 2B - Dependent Privilege Descriptors Still Exist
	"2B000": "dependent_privilege_descriptors_still_exist",
	"2BP01": "dependent_objects_still_exist",
	// Class 2D - Invalid Transaction Termination
	"2D000": "invalid_transaction_termination",
	// Class 2F - SQL Routine Exception
	"2F000": "sql_routine_exception",
	"2F005": "function_executed_no_return_statement",
	"2F002": "modifying_sql_data_not_permitted",
	"2F003": "prohibited_sql_statement_attempted",
	"2F004": "reading_sql_data_not_permitted",
	// Class 34 - Invalid Cursor Name
	"34000": "invalid_cursor_name",
	// Class 38 - External Routine Exception
	"38000": "external_routine_exception",
	"38001": "containing_sql_not_permitted",
	"38002": "modifying_sql_data_not_permitted",
	"38003": "prohibited_sql_statement_attempted",
	"38004": "reading_sql_data_not_permitted",
	// Class 39 - External Routine Invocation Exception
	"39000": "external_routine_invocation_exception",
	"39001": "invalid_sqlstate_returned",
	"39004": "null_value_not_allowed",
	"39P01": "trigger_protocol_violated",
	"39P02": "srf_protocol_violated",
	// Class 3B - Savepoint Exception
	"3B000": "savepoint_exception",
	"3B001": "invalid_savepoint_specification",
	// Class 3D - Invalid Catalog Name
	"3D000": "invalid_catalog_name",
	// Class 3F - Invalid Schema Name
	"3F000": "invalid_schema_name",
	// Class 40 - Transaction Rollback
	"40000": "transaction_rollback",
	"40002": "transaction_integrity_constraint_violation",
	"40001": "serialization_failure",
	"40003": "statement_completion_unknown",
	"40P01": "deadlock_detected",
	// Class 42 - Syntax Error or Access Rule Violation
	"42000": "syntax_error_or_access_rule_violation",
	"42601": "syntax_error",
	"42501": "insufficient_privilege",
	"42846": "cannot_coerce",
	"42803": "grouping_error",
	"42P20": "windowing_error",
	"42P19": "invalid_recursion",
	"42830": "invalid_foreign_key",
	"42602": "invalid_name",
	"42622": "name_too_long",
	"42939": "reserved_name",
	"42804": "datatype_mismatch",
	"42P18": "indeterminate_datatype",
	"42P21": "collation_mismatch",
	"42P22": "indeterminate_collation",
	"42809": "wrong_object_type",
	"42703": "undefined_column",
	"42883": "undefined_function",
	"42P01": "undefined_table",
	"42P02": "undefined_parameter",
	"42704": "undefined_object",
	"42701": "duplicate_column",
	"42P03": "duplicate_cursor",
	"42P04": "duplicate_database",
	"42723": "duplicate_function",
	"42P05": "duplicate_prepared_statement",
	"42P06": "duplicate_schema",
	"42P07": "duplicate_table",
	"42712": "duplicate_alias",
	"42710": "duplicate_object",
	"42702": "ambiguous_column",
	"42725": "ambiguous_function",
	"42P08": "ambiguous_parameter",
	"42P09": "ambiguous_alias",
	"42P10": "invalid_column_reference",
	"42611": "invalid_column_definition",
	"42P11": "invalid_cursor_definition",
	"42P12": "invalid_database_definition",
	"42P13": "invalid_function_definition",
	"42P14": "invalid_prepared_statement_definition",
	"42P15": "invalid_schema_definition",
	"42P16": "invalid_table_definition",
	"42P17": "invalid_object_definition",
	// Class 44 - WITH CHECK OPTION Violation
	"44000": "with_check_option_violation",
	// Class 53 - Insufficient Resources
	"53000": "insufficient_resources",
	"53100": "disk_full",
	"53200": "out_of_memory",
	"53300": "too_many_connections",
	"53400": "configuration_limit_exceeded",
	// Class 54 - Program Limit Exceeded
	"54000": "program_limit_exceeded",
	"54001": "statement_too_complex",
	"54011": "too_many_columns",
	"54023": "too_many_arguments",
	// Class 55 - Object Not In Prerequisite State
	"55000": "object_not_in_prerequisite_state",
	"55006": "object_in_use",
	"55P02": "cant_change_runtime_param",
	"55P03": "lock_not_available",
	// Class 57 - Operator Intervention
	"57000": "operator_intervention",
	"57014": "query_canceled",
	"57P01": "admin_shutdown",
	"57P02": "crash_shutdown",
	"57P03": "cannot_connect_now",
	"57P04": "database_dropped",
	// Class 58 - System Error (errors external to PostgreSQL itself)
	"58000": "system_error",
	"58030": "io_error",
	"58P01": "undefined_file",
	"58P02": "duplicate_file",
	// Class F0 - Configuration File Error
	"F0000": "config_file_error",
	"F0001": "lock_file_exists",
	// Class HV - Foreign Data Wrapper Error (SQL/MED)
	"HV000": "fdw_error",
	"HV005": "fdw_column_name_not_found",
	"HV002": "fdw_dynamic_parameter_value_needed",
	"HV010": "fdw_function_sequence_error",
	"HV021": "fdw_inconsistent_descriptor_information",
	"HV024": "fdw_invalid_attribute_value",
	"HV007": "fdw_invalid_column_name",
	"HV008": "fdw_invalid_column_number",
	"HV004": "fdw_invalid_data_type",
	"HV006": "fdw_invalid_data_type_descriptors",
	"HV091": "fdw_invalid_descriptor_field_identifier",
	"HV00B": "fdw_invalid_handle",
	"HV00C": "fdw_invalid_option_index",
	"HV00D": "fdw_invalid_option_name",
	"HV090": "fdw_invalid_string_length_or_buffer_length",
	"HV00A": "fdw_invalid_string_format",
	"HV009": "fdw_invalid_use_of_null_pointer",
	"HV014": "fdw_too_many_handles",
	"HV001": "fdw_out_of_memory",
	"HV00P": "fdw_no_schemas",
	"HV00J": "fdw_option_name_not_found",
	"HV00K": "fdw_reply_handle",
	"HV00Q": "fdw_schema_not_found",
	"HV00R": "fdw_table_not_found",
	"HV00L": "fdw_unable_to_create_execution",
	"HV00M": "fdw_unable_to_create_reply",
	"HV00N": "fdw_unable_to_establish_connection",
	// Class P0 - PL/pgSQL Error
	"P0000": "plpgsql_error",
	"P0001": "raise_exception",
	"P0002": "no_data_found",
	"P0003": "too_many_rows",
	// Class XX - Internal Error
	"XX000": "internal_error",
	"XX001": "data_corrupted",
	"XX002": "index_corrupted",
}

func parseError(r *readBuf) *Error {
	err := new(Error)
	for t := r.byte(); t != 0; t = r.byte() {
		msg := r.string()
		switch t {
		case 'S':
			err.Severity = msg
		case 'C':
			err.Code = ErrorCode(msg)
		case 'M':
			err.Message = msg
		case 'D':
			err.Detail = msg
		case 'H':
			err.Hint = msg
		case 'P':
			err.Position = msg
		case 'p':
			err.InternalPosition = msg
		case 'q':
			err.InternalQuery = msg
		case 'W':
			err.Where = msg
		case 's':
			err.Schema = msg
		case 't':
			err.Table = msg
		case 'c':
			err.Column = msg
		case 'd':
			err.DataTypeName = msg
		case 'n':
			err.Constraint = msg
		case 'F':
			err.File = msg
		case 'L':
			err.Line = msg
		case 'R':
			err.Routine = msg
		}
	}
	return err
}

// Fatal returns true if the Error Severity is fatal.
func (err *Error) Fatal() bool {
	return err.Severity == Efatal
}

// SQLState returns the SQLState of the error.
func (err *Error) SQLState() string {
	return string(err.Code)
}

// Get implements the legacy PGError interface. New code should use the fields
// of the Error struct directly.
func (err *Error) Get(k byte) (v string) {
	switch k {
	case 'S':
		return err.Severity
	case 'C':
		return string(err.Code)
	case 'M':
		return err.Message
	case 'D':
		return err.Detail
	case 'H':
		return err.Hint
	case 'P':
		return err.Position
	case 'p':
		return err.InternalPosition
	case 'q':
		return err.InternalQuery
	case 'W':
		return err.Where
	case 's':
		return err.Schema
	case 't':
		return err.Table
	case 'c':
		return err.Column
	case 'd':
		return err.DataTypeName
	case 'n':
		return err.Constraint
	case 'F':
		return err.File
	case 'L':
		return err.Line
	case 'R':
		return err.Routine
	}
	return ""
}

func (err Error) Error() string {
	return "pq: " + err.Message
}

// PGError is an interface used by previous versions of pq. It is provided
// only to support legacy code. New code should use the Error type.
type PGError interface {
	Error() string
	Fatal() bool
	Get(k byte) (v string)
}

func errorf(s string, args ...interface{}) {
	panic(fmt.Errorf("pq: %s", fmt.Sprintf(s, args...)))
}

// TODO(ainar-g) Rename to errorf after removing panics.
func fmterrorf(s string, args ...interface{}) error {
	return fmt.Errorf("pq: %s", fmt.Sprintf(s, args...))
}

func errRecoverNoErrBadConn(err *error) {
	e := recover()
	if e == nil {
		// Do nothing
		return
	}
	var ok bool
	*err, ok = e.(error)
	if !ok {
		*err = fmt.Errorf("pq: unexpected error: %#v", e)
	}
}

func (cn *conn) errRecover(err *error) {
	e := recover()
	switch v := e.(type) {
	case nil:
		// Do nothing
	case runtime.Error:
		cn.err.set(driver.ErrBadConn)
		panic(v)
	case *Error:
		// if v.Fatal() {
		// 	*err = driver.ErrBadConn
		// } else {
		// 	*err = v
		// }
		*err = v
	case *net.OpError:
		cn.err.set(driver.ErrBadConn)
		*err = v
	case *safeRetryError:
		cn.err.set(driver.ErrBadConn)
		*err = driver.ErrBadConn
	case error:
		if v == io.EOF || v.Error() == "remote error: handshake failure" {
			*err = driver.ErrBadConn
		} else {
			*err = v
		}

	default:
		cn.err.set(driver.ErrBadConn)
		panic(fmt.Sprintf("unknown error: %#v", e))
	}

	// Any time we return ErrBadConn, we need to remember it since *Tx doesn't
	// mark the connection bad in database/sql.
	if *err == driver.ErrBadConn {
		cn.err.set(driver.ErrBadConn)
	}
}

type connectError struct {
	config         *Config
	msg            string
	err            error
	fallbackConfig *FallbackConfig
}

func (e *connectError) Error() string {
	sb := &strings.Builder{}
	sb.WriteString("failed to connect to ")
	var host = e.config.Host
	var port = e.config.Port
	if e.fallbackConfig != nil && e.fallbackConfig.Host != "" {
		host = e.fallbackConfig.Host
		port = e.fallbackConfig.Port
	}
	sb.WriteString(fmt.Sprintf("`host=%s port=%v user=%s database=%s`: %s ", host, port, e.config.User, e.config.Database, e.msg))
	if e.err != nil {
		sb.WriteString(e.err.Error())
	}
	return sb.String()
}

func (e *connectError) Unwrap() error {
	return e.err
}

type parseConfigError struct {
	connString string
	msg        string
	err        error
}

func (e *parseConfigError) Error() string {
	connString := redactPW(e.connString)
	if e.err == nil {
		return fmt.Sprintf("cannot parse `%s`: %s", connString, e.msg)
	}
	return fmt.Sprintf("cannot parse `%s`: %s (%s)", connString, e.msg, e.err.Error())
}

func (e *parseConfigError) Unwrap() error {
	return e.err
}

func redactPW(connString string) string {
	if strings.HasPrefix(connString, "postgres://") || strings.HasPrefix(connString, "postgresql://") {
		if u, err := url.Parse(connString); err == nil {
			return redactURL(u)
		}
	}
	quotedDSN := regexp.MustCompile(`password='[^']*'`)
	connString = quotedDSN.ReplaceAllLiteralString(connString, "password=xxxxx")
	plainDSN := regexp.MustCompile(`password=[^ ]*`)
	connString = plainDSN.ReplaceAllLiteralString(connString, "password=xxxxx")
	brokenURL := regexp.MustCompile(`:[^:@]+?@`)
	connString = brokenURL.ReplaceAllLiteralString(connString, ":xxxxxx@")
	return connString
}

func redactURL(u *url.URL) string {
	if u == nil {
		return ""
	}
	if _, pwSet := u.User.Password(); pwSet {
		u.User = url.UserPassword(u.User.Username(), "xxxxx")
	}
	return u.String()
}