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{}
    }
}