module pg

import orm
import time
import net.conv

// ---- ORM on Conn (single pinned connection) ----

// select is used internally by V's ORM for processing `SELECT ` queries.
pub fn (c &Conn) select(config orm.SelectConfig, data orm.QueryData, where orm.QueryData) ![][]orm.Primitive {
	c.ensure_active()!
	where_with_tenant := orm.apply_tenant_filter(config.table, where)
	query := orm.orm_select_gen(config, '"', true, '$', 1, where_with_tenant)

	rows := pg_stmt_worker(c, query, where_with_tenant, data)!

	mut ret := [][]orm.Primitive{}

	for row in rows {
		mut row_data := []orm.Primitive{}
		for i, val in row.vals {
			row_data << val_to_primitive(val, config.types[i])!
		}
		ret << row_data
	}

	return ret
}

// insert is used internally by V's ORM for processing `INSERT ` queries.
pub fn (c &Conn) insert(table orm.Table, data orm.QueryData) ! {
	c.ensure_active()!
	query, converted_data :=
		orm.orm_stmt_gen(.pg, table, '"', .insert, true, '$', 1, data, orm.QueryData{})
	pg_stmt_worker(c, query, converted_data, orm.QueryData{})!
}

// update is used internally by V's ORM for processing `UPDATE ` queries.
pub fn (c &Conn) update(table orm.Table, data orm.QueryData, where orm.QueryData) ! {
	c.ensure_active()!
	where_with_tenant := orm.apply_tenant_filter(table, where)
	query, _ := orm.orm_stmt_gen(.default, table, '"', .update, true, '$', 1, data,
		where_with_tenant)
	pg_stmt_worker(c, query, data, where_with_tenant)!
}

// delete is used internally by V's ORM for processing `DELETE ` queries.
pub fn (c &Conn) delete(table orm.Table, where orm.QueryData) ! {
	c.ensure_active()!
	where_with_tenant := orm.apply_tenant_filter(table, where)
	query, _ := orm.orm_stmt_gen(.default, table, '"', .delete, true, '$', 1, orm.QueryData{},
		where_with_tenant)
	pg_stmt_worker(c, query, orm.QueryData{}, where_with_tenant)!
}

// last_id is used internally by V's ORM for post-processing `INSERT ` queries.
pub fn (c &Conn) last_id() int {
	query := 'SELECT LASTVAL();'

	return c.q_int(query) or { 0 }
}

// create is used internally by V's ORM for processing table creation queries (DDL).
pub fn (c &Conn) create(table orm.Table, fields []orm.TableField) ! {
	query := orm.orm_table_gen(.pg, table, '"', true, 0, fields, pg_type_from_v, false) or {
		return err
	}
	stmts := query.split(';')
	for stmt in stmts {
		if stmt != '' {
			c.exec(stmt + ';')!
		}
	}
}

// drop is used internally by V's ORM for processing table destroying queries (DDL).
pub fn (c &Conn) drop(table orm.Table) ! {
	query := 'DROP TABLE "${table.name}";'
	c.exec(query)!
}

// orm_begin starts a transaction on this conn.
pub fn (c &Conn) orm_begin() ! {
	c.begin_on_conn()!
}

// orm_commit commits the transaction on this conn.
pub fn (c &Conn) orm_commit() ! {
	c.commit()!
}

// orm_rollback rolls back the transaction on this conn.
pub fn (c &Conn) orm_rollback() ! {
	c.rollback()!
}

// orm_savepoint creates a savepoint on this conn.
pub fn (c &Conn) orm_savepoint(name string) ! {
	c.savepoint(name)!
}

// orm_rollback_to rolls back to a savepoint on this conn.
pub fn (c &Conn) orm_rollback_to(name string) ! {
	c.rollback_to(name)!
}

// orm_release_savepoint releases a savepoint on this conn.
pub fn (c &Conn) orm_release_savepoint(name string) ! {
	c.release_savepoint(name)!
}

// ---- ORM on DB (acquire-use-release per call) ----

// select acquires a conn from the pool and runs the ORM SELECT on it.
pub fn (mut db DB) select(config orm.SelectConfig, data orm.QueryData, where orm.QueryData) ![][]orm.Primitive {
	mut c := db.pool.acquire()!
	defer {
		c.close() or {}
	}
	return c.select(config, data, where)
}

// insert acquires a conn from the pool, runs the ORM INSERT on it, and
// stashes LASTVAL() captured on the same session for the calling thread.
// V's `sql db { insert ... }` macro emits a follow-up `db.last_id()` call;
// stashing here lets that read return the correct id even though the pool
// may hand out a different conn for the second call.
pub fn (mut db DB) insert(table orm.Table, data orm.QueryData) ! {
	mut c := db.pool.acquire()!
	defer {
		c.close() or {}
	}
	c.insert(table, data)!
	db.pool.stash_last_id(c.last_id())
}

// update acquires a conn from the pool and runs the ORM UPDATE on it.
pub fn (mut db DB) update(table orm.Table, data orm.QueryData, where orm.QueryData) ! {
	mut c := db.pool.acquire()!
	defer {
		c.close() or {}
	}
	c.update(table, data, where)!
}

// delete acquires a conn from the pool and runs the ORM DELETE on it.
pub fn (mut db DB) delete(table orm.Table, where orm.QueryData) ! {
	mut c := db.pool.acquire()!
	defer {
		c.close() or {}
	}
	c.delete(table, where)!
}

// create acquires a conn from the pool and runs CREATE TABLE on it.
pub fn (mut db DB) create(table orm.Table, fields []orm.TableField) ! {
	mut c := db.pool.acquire()!
	defer {
		c.close() or {}
	}
	c.create(table, fields)!
}

// drop acquires a conn from the pool and runs DROP TABLE on it.
pub fn (mut db DB) drop(table orm.Table) ! {
	mut c := db.pool.acquire()!
	defer {
		c.close() or {}
	}
	c.drop(table)!
}

// last_id returns the id stashed by this thread's most recent `DB.insert`
// (or 0 if there is none). LASTVAL() itself is session-scoped, so calling
// it on a freshly-checked-out pool conn would return the wrong value or 0;
// `DB.insert` captures it on the same conn that ran the INSERT and stashes
// it per-thread, which is what V's ORM macro expects.
pub fn (mut db DB) last_id() int {
	return db.pool.take_last_id()
}

// ---- ORM on Tx (use the pinned conn) ----

// select runs the ORM SELECT on the pinned transaction conn.
pub fn (mut tx Tx) select(config orm.SelectConfig, data orm.QueryData, where orm.QueryData) ![][]orm.Primitive {
	tx.ensure_active()!
	return tx.conn.select(config, data, where)
}

// insert runs the ORM INSERT on the pinned transaction conn.
pub fn (mut tx Tx) insert(table orm.Table, data orm.QueryData) ! {
	tx.ensure_active()!
	tx.conn.insert(table, data)!
}

// update runs the ORM UPDATE on the pinned transaction conn.
pub fn (mut tx Tx) update(table orm.Table, data orm.QueryData, where orm.QueryData) ! {
	tx.ensure_active()!
	tx.conn.update(table, data, where)!
}

// delete runs the ORM DELETE on the pinned transaction conn.
pub fn (mut tx Tx) delete(table orm.Table, where orm.QueryData) ! {
	tx.ensure_active()!
	tx.conn.delete(table, where)!
}

// create runs CREATE TABLE on the pinned transaction conn.
pub fn (mut tx Tx) create(table orm.Table, fields []orm.TableField) ! {
	tx.ensure_active()!
	tx.conn.create(table, fields)!
}

// drop runs DROP TABLE on the pinned transaction conn.
pub fn (mut tx Tx) drop(table orm.Table) ! {
	tx.ensure_active()!
	tx.conn.drop(table)!
}

// last_id returns the last inserted id on the pinned conn.
pub fn (mut tx Tx) last_id() int {
	if tx.done || isnil(tx.conn) {
		return 0
	}
	return tx.conn.last_id()
}

// orm_begin is a no-op on Tx (begin already ran when the Tx was created).
// It exists so Tx satisfies `orm.TransactionalConnection` for nested savepoints.
pub fn (mut tx Tx) orm_begin() ! {
}

// orm_commit commits the Tx.
pub fn (mut tx Tx) orm_commit() ! {
	tx.commit()!
}

// orm_rollback rolls back the Tx.
pub fn (mut tx Tx) orm_rollback() ! {
	tx.rollback()!
}

// orm_savepoint creates a savepoint inside the Tx.
pub fn (mut tx Tx) orm_savepoint(name string) ! {
	tx.savepoint(name)!
}

// orm_rollback_to rolls back to a savepoint inside the Tx.
pub fn (mut tx Tx) orm_rollback_to(name string) ! {
	tx.rollback_to(name)!
}

// orm_release_savepoint releases a savepoint inside the Tx.
pub fn (mut tx Tx) orm_release_savepoint(name string) ! {
	tx.release_savepoint(name)!
}

// ---- utils ----

fn pg_stmt_binder(mut types []u32, mut vals []&char, mut lens []int, mut formats []int, d orm.QueryData) {
	for data in d.data {
		pg_stmt_match(mut types, mut vals, mut lens, mut formats, data)
	}
}

fn pg_stmt_match_array[T](mut types []u32, mut vals []&char, mut lens []int, mut formats []int, data []T) {
	for element in data {
		pg_stmt_match(mut types, mut vals, mut lens, mut formats, orm.Primitive(element))
	}
}

fn pg_stmt_match(mut types []u32, mut vals []&char, mut lens []int, mut formats []int, data orm.Primitive) {
	match data {
		bool {
			types << u32(Oid.t_bool)
			vals << &char(&data)
			lens << int(sizeof(bool))
			formats << 1
		}
		u8 {
			types << u32(Oid.t_char)
			vals << &char(&data)
			lens << int(sizeof(u8))
			formats << 1
		}
		u16 {
			types << u32(Oid.t_int2)
			num := conv.hton16(data)
			vals << &char(&num)
			lens << int(sizeof(u16))
			formats << 1
		}
		u32 {
			types << u32(Oid.t_int4)
			num := conv.hton32(data)
			vals << &char(&num)
			lens << int(sizeof(u32))
			formats << 1
		}
		u64 {
			types << u32(Oid.t_int8)
			num := conv.hton64(data)
			vals << &char(&num)
			lens << int(sizeof(u64))
			formats << 1
		}
		i8 {
			types << u32(Oid.t_char)
			vals << &char(&data)
			lens << int(sizeof(i8))
			formats << 1
		}
		i16 {
			types << u32(Oid.t_int2)
			num := conv.hton16(u16(data))
			vals << &char(&num)
			lens << int(sizeof(i16))
			formats << 1
		}
		int {
			types << u32(Oid.t_int4)
			num := conv.hton32(u32(data))
			vals << &char(&num)
			lens << int(sizeof(int))
			formats << 1
		}
		i64 {
			types << u32(Oid.t_int8)
			num := conv.hton64(u64(data))
			vals << &char(&num)
			lens << int(sizeof(i64))
			formats << 1
		}
		f32 {
			types << u32(Oid.t_float4)
			num := conv.htonf32(f32(data))
			vals << &char(&num)
			lens << int(sizeof(f32))
			formats << 1
		}
		f64 {
			types << u32(Oid.t_float8)
			num := conv.htonf64(f64(data))
			vals << &char(&num)
			lens << int(sizeof(f64))
			formats << 1
		}
		string {
			// If paramTypes is NULL, or any particular element in the array is zero,
			// the server infers a data type for the parameter symbol in the same way
			// it would do for an untyped literal string.
			types << u32(0)
			vals << &char(data.str)
			lens << data.len
			formats << 0
		}
		time.Time {
			datetime := data.format_ss()
			types << u32(0)
			vals << &char(datetime.str)
			lens << datetime.len
			formats << 0
		}
		orm.InfixType {
			pg_stmt_match(mut types, mut vals, mut lens, mut formats, data.right)
		}
		orm.Null {
			types << u32(0) // we do not know col type, let server infer
			vals << &char(unsafe { nil }) // NULL pointer indicates NULL
			lens << int(0) // ignored
			formats << 0 // ignored
		}
		[]orm.Primitive {
			pg_stmt_match_array(mut types, mut vals, mut lens, mut formats, data)
		}
		[]bool {
			pg_stmt_match_array(mut types, mut vals, mut lens, mut formats, data)
		}
		[]f32 {
			pg_stmt_match_array(mut types, mut vals, mut lens, mut formats, data)
		}
		[]f64 {
			pg_stmt_match_array(mut types, mut vals, mut lens, mut formats, data)
		}
		[]i16 {
			pg_stmt_match_array(mut types, mut vals, mut lens, mut formats, data)
		}
		[]i64 {
			pg_stmt_match_array(mut types, mut vals, mut lens, mut formats, data)
		}
		[]i8 {
			pg_stmt_match_array(mut types, mut vals, mut lens, mut formats, data)
		}
		[]int {
			pg_stmt_match_array(mut types, mut vals, mut lens, mut formats, data)
		}
		[]string {
			pg_stmt_match_array(mut types, mut vals, mut lens, mut formats, data)
		}
		[]time.Time {
			pg_stmt_match_array(mut types, mut vals, mut lens, mut formats, data)
		}
		[]u16 {
			pg_stmt_match_array(mut types, mut vals, mut lens, mut formats, data)
		}
		[]u32 {
			pg_stmt_match_array(mut types, mut vals, mut lens, mut formats, data)
		}
		[]u64 {
			pg_stmt_match_array(mut types, mut vals, mut lens, mut formats, data)
		}
		[]u8 {
			pg_stmt_match_array(mut types, mut vals, mut lens, mut formats, data)
		}
		[]orm.InfixType {
			pg_stmt_match_array(mut types, mut vals, mut lens, mut formats, data)
		}
	}
}

fn pg_type_from_v(typ int) !string {
	str := match typ {
		orm.type_idx['i8'], orm.type_idx['i16'], orm.type_idx['u8'], orm.type_idx['u16'] {
			'SMALLINT'
		}
		orm.type_idx['bool'] {
			'BOOLEAN'
		}
		orm.type_idx['int'], orm.type_idx['u32'] {
			'INT'
		}
		orm.time_ {
			'TIMESTAMP'
		}
		orm.enum_ {
			'BIGINT'
		}
		orm.type_idx['i64'], orm.type_idx['u64'] {
			'BIGINT'
		}
		orm.float[0] {
			'REAL'
		}
		orm.float[1] {
			'DOUBLE PRECISION'
		}
		orm.type_string {
			'TEXT'
		}
		orm.serial {
			'SERIAL'
		}
		else {
			''
		}
	}

	if str == '' {
		return error('Unknown type ${typ}')
	}
	return str
}

fn val_to_primitive(val ?string, typ int) !orm.Primitive {
	if str := val {
		match typ {
			// bool
			orm.type_idx['bool'] {
				return orm.Primitive(str == 't')
			}
			// i8
			orm.type_idx['i8'] {
				return orm.Primitive(str.i8())
			}
			// i16
			orm.type_idx['i16'] {
				return orm.Primitive(str.i16())
			}
			// int
			orm.type_idx['int'] {
				return orm.Primitive(str.int())
			}
			// i64
			orm.type_idx['i64'] {
				return orm.Primitive(str.i64())
			}
			// u8
			orm.type_idx['u8'] {
				data := str.i8()
				return orm.Primitive(*unsafe { &u8(&data) })
			}
			// u16
			orm.type_idx['u16'] {
				data := str.i16()
				return orm.Primitive(*unsafe { &u16(&data) })
			}
			// u32
			orm.type_idx['u32'] {
				data := str.int()
				return orm.Primitive(*unsafe { &u32(&data) })
			}
			// u64
			orm.type_idx['u64'] {
				data := str.i64()
				return orm.Primitive(*unsafe { &u64(&data) })
			}
			// f32
			orm.type_idx['f32'] {
				return orm.Primitive(str.f32())
			}
			// f64
			orm.type_idx['f64'] {
				return orm.Primitive(str.f64())
			}
			orm.type_string {
				return orm.Primitive(str)
			}
			orm.time_ {
				if str.contains_any(' /:-') {
					date_time_str := time.parse(str)!
					return orm.Primitive(date_time_str)
				}

				timestamp := str.int()
				return orm.Primitive(time.unix(timestamp))
			}
			orm.enum_ {
				return orm.Primitive(str.i64())
			}
			else {}
		}

		return error('Unknown field type ${typ}')
	} else {
		return orm.Null{}
	}
}