use std::error::Error;

use std::fmt::{self, Debug, Display, Formatter};

use atoi::atoi;

use smallvec::alloc::borrow::Cow;

use crate::error::DatabaseError;

use crate::postgres::message::{Notice, PgSeverity};

/// An error returned from the PostgreSQL database.

pub struct PgDatabaseError(pub(crate) Notice);

// Error message fields are documented:

// https://www.postgresql.org/docs/current/protocol-error-fields.html

impl PgDatabaseError {

#[inline]

pub fn severity(&self) -> PgSeverity {

self.0.severity()

}

/// The [SQLSTATE](https://www.postgresql.org/docs/current/errcodes-appendix.html) code for

/// this error.

#[inline]

pub fn code(&self) -> &str {

self.0.code()

}

/// The primary human-readable error message. This should be accurate but

/// terse (typically one line).

#[inline]

pub fn message(&self) -> &str {

self.0.message()

}

/// An optional secondary error message carrying more detail about the problem.

/// Might run to multiple lines.

#[inline]

pub fn detail(&self) -> Option<&str> {

self.0.get(b'D')

}

/// An optional suggestion what to do about the problem. This is intended to differ from

/// `detail` in that it offers advice (potentially inappropriate) rather than hard facts.

/// Might run to multiple lines.

#[inline]

pub fn hint(&self) -> Option<&str> {

self.0.get(b'H')

}

/// Indicates an error cursor position as an index into the original query string; or,

/// a position into an internally generated query.

#[inline]

pub fn position(&self) -> Option<PgErrorPosition<'_>> {

self.0

.get_raw(b'P')

.and_then(atoi)

.map(PgErrorPosition::Original)

.or_else(|| {

let position = self.0.get_raw(b'p').and_then(atoi)?;

let query = self.0.get(b'q')?;

Some(PgErrorPosition::Internal { position, query })

})

}

/// An indication of the context in which the error occurred. Presently this includes a call

/// stack traceback of active procedural language functions and internally-generated queries.

/// The trace is one entry per line, most recent first.

pub fn r#where(&self) -> Option<&str> {

self.0.get(b'W')

}

/// If this error is with a specific database object, the

/// name of the schema containing that object, if any.

pub fn schema(&self) -> Option<&str> {

self.0.get(b's')

}

/// If this error is with a specific table, the name of the table.

pub fn table(&self) -> Option<&str> {

self.0.get(b't')

}

/// If the error is with a specific table column, the name of the column.

pub fn column(&self) -> Option<&str> {

self.0.get(b'c')

}

/// If the error is with a specific data type, the name of the data type.

pub fn data_type(&self) -> Option<&str> {

self.0.get(b'd')

}

/// If the error is with a specific constraint, the name of the constraint.

/// For this purpose, indexes are constraints, even if they weren't created

/// with constraint syntax.

pub fn constraint(&self) -> Option<&str> {

self.0.get(b'n')

}

/// The file name of the source-code location where this error was reported.

pub fn file(&self) -> Option<&str> {

self.0.get(b'F')

}

/// The line number of the source-code location where this error was reported.

pub fn line(&self) -> Option<usize> {

self.0.get_raw(b'L').and_then(atoi)

}

/// The name of the source-code routine reporting this error.

pub fn routine(&self) -> Option<&str> {

self.0.get(b'R')

}

}

#[derive(Debug, Eq, PartialEq)]

pub enum PgErrorPosition<'a> {

/// A position (in characters) into the original query.

Original(usize),

/// A position into the internally-generated query.

Internal {

/// The position in characters.

position: usize,

/// The text of a failed internally-generated command. This could be, for example,

/// the SQL query issued by a PL/pgSQL function.

query: &'a str,

},

}

impl Debug for PgDatabaseError {

fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {

f.debug_struct("PgDatabaseError")

.field("severity", &self.severity())

.field("code", &self.code())

.field("message", &self.message())

.field("detail", &self.detail())

.field("hint", &self.hint())

.field("position", &self.position())

.field("where", &self.r#where())

.field("schema", &self.schema())

.field("table", &self.table())

.field("column", &self.column())

.field("data_type", &self.data_type())

.field("constraint", &self.constraint())

.field("file", &self.file())

.field("line", &self.line())

.field("routine", &self.routine())

.finish()

}

}

impl Display for PgDatabaseError {

fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {

f.write_str(self.message())

}

}

impl Error for PgDatabaseError {}

impl DatabaseError for PgDatabaseError {

fn message(&self) -> &str {

self.message()

}

fn code(&self) -> Option<Cow<'_, str>> {

Some(Cow::Borrowed(self.code()))

}

fn offset(&self) -> Option<usize> {

self.0.get_raw(b'P').and_then(atoi)

}

#[doc(hidden)]

fn as_error(&self) -> &(dyn Error + Send + Sync + 'static) {

self

}

#[doc(hidden)]

fn as_error_mut(&mut self) -> &mut (dyn Error + Send + Sync + 'static) {

self

}

#[doc(hidden)]

fn into_error(self: Box<Self>) -> Box<dyn Error + Send + Sync + 'static> {

self

}

fn is_transient_in_connect_phase(&self) -> bool {

// https://www.postgresql.org/docs/current/errcodes-appendix.html

[

// too_many_connections

// This may be returned if we just un-gracefully closed a connection,

// give the database a chance to notice it and clean it up.

"53300",

// cannot_connect_now

// Returned if the database is still starting up.

"57P03",

]

.contains(&self.code())

}

fn constraint(&self) -> Option<&str> {

self.constraint()

}

}