module sqlite

import orm
import time

// select is used internally by V's ORM for processing `SELECT ` queries
pub fn (db DB) select(config orm.SelectConfig, data orm.QueryData, where orm.QueryData) ![][]orm.Primitive {
    where_with_tenant := orm.apply_tenant_filter(config.table, where)
    $if trace_orm_where ? {
        eprintln('> sqlite.select: where.fields.len = ${where.fields.len}')
        eprintln('> sqlite.select: where.kinds.len = ${where.kinds.len}')
    }
    // 1. Create query and bind necessary data
    query := orm.orm_select_gen(config, '`', true, '?', 1, where_with_tenant)
    $if trace_sqlite ? {
        eprintln('> select query: "${query}"')
    }
    stmt := db.new_init_stmt(query)!
    defer {
        stmt.finalize()
    }
    mut c := 1
    sqlite_stmt_binder(stmt, where_with_tenant, query, mut c)!
    sqlite_stmt_binder(stmt, data, query, mut c)!

    mut ret := [][]orm.Primitive{}
    for {
        // 2. Parse returned values
        step := stmt.step()
        if step == sqlite_done {
            break
        }
        if step != sqlite_ok && step != sqlite_row {
            break
        }
        mut row := []orm.Primitive{}
        for i, typ in config.types {
            primitive := stmt.sqlite_select_column(i, typ)!
            row << primitive
        }
        ret << row
    }
    return ret
}

// sql stmt

// insert is used internally by V's ORM for processing `INSERT ` queries
pub fn (db DB) insert(table orm.Table, data orm.QueryData) ! {
    query, converted_data :=
        orm.orm_stmt_gen(.sqlite, table, '`', .insert, true, '?', 1, data, orm.QueryData{})
    sqlite_stmt_worker(db, query, converted_data, orm.QueryData{})!
}

// update is used internally by V's ORM for processing `UPDATE ` queries
pub fn (db DB) update(table orm.Table, data orm.QueryData, where orm.QueryData) ! {
    where_with_tenant := orm.apply_tenant_filter(table, where)
    query, _ := orm.orm_stmt_gen(.sqlite, table, '`', .update, true, '?', 1, data,
        where_with_tenant)
    sqlite_stmt_worker(db, query, data, where_with_tenant)!
}

// delete is used internally by V's ORM for processing `DELETE ` queries
pub fn (db DB) delete(table orm.Table, where orm.QueryData) ! {
    where_with_tenant := orm.apply_tenant_filter(table, where)
    query, _ := orm.orm_stmt_gen(.sqlite, table, '`', .delete, true, '?', 1, orm.QueryData{},
        where_with_tenant)
    sqlite_stmt_worker(db, query, orm.QueryData{}, where_with_tenant)!
}

// last_id is used internally by V's ORM for post-processing `INSERT ` queries
pub fn (db DB) last_id() int {
    query := 'SELECT last_insert_rowid();'

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

// DDL (table creation/destroying etc)

// create is used internally by V's ORM for processing table creation queries (DDL)
pub fn (db DB) create(table orm.Table, fields []orm.TableField) ! {
    query := orm.orm_table_gen(.sqlite, table, '`', true, 0, fields, sqlite_type_from_v, false) or {
        return err
    }
    sqlite_stmt_worker(db, query, orm.QueryData{}, orm.QueryData{})!
}

// drop is used internally by V's ORM for processing table destroying queries (DDL)
pub fn (db DB) drop(table orm.Table) ! {
    query := 'DROP TABLE `${table.name}`;'
    sqlite_stmt_worker(db, query, orm.QueryData{}, orm.QueryData{})!
}

// orm_begin starts a transaction for ORM helpers.
pub fn (mut db DB) orm_begin() ! {
    db.begin()!
}

// orm_commit commits a transaction for ORM helpers.
pub fn (mut db DB) orm_commit() ! {
    db.commit()!
}

// orm_rollback rolls back a transaction for ORM helpers.
pub fn (mut db DB) orm_rollback() ! {
    db.rollback()!
}

// orm_savepoint creates a savepoint for ORM helpers.
pub fn (mut db DB) orm_savepoint(name string) ! {
    db.savepoint(name)!
}

// orm_rollback_to rolls back to a savepoint for ORM helpers.
pub fn (mut db DB) orm_rollback_to(name string) ! {
    db.rollback_to(name)!
}

// orm_release_savepoint releases a savepoint for ORM helpers.
pub fn (mut db DB) orm_release_savepoint(name string) ! {
    db.release_savepoint(name)!
}

// helper

// Executes query and bind prepared statement data directly
fn sqlite_stmt_worker(db DB, query string, data orm.QueryData, where orm.QueryData) ! {
    $if trace_sqlite ? {
        eprintln('> sqlite_stmt_worker query: "${query}"')
    }
    stmt := db.new_init_stmt(query)!
    defer {
        stmt.finalize()
    }
    mut c := 1
    sqlite_stmt_binder(stmt, data, query, mut c)!
    sqlite_stmt_binder(stmt, where, query, mut c)!
    stmt.orm_step(query)!
}

// Binds all values of d in the prepared statement
fn sqlite_stmt_binder(stmt Stmt, d orm.QueryData, query string, mut c &int) ! {
    for data in d.data {
        err := bind(stmt, mut c, data)

        if err != 0 {
            return stmt.db.error_message(err, query)
        }
        if !sqlite_primitive_is_array(data) {
            c++
        }
    }
}

fn sqlite_primitive_is_array(data orm.Primitive) bool {
    return match data {
        []orm.Primitive, []bool, []f32, []f64, []i16, []i64, []i8, []int, []string, []time.Time,
        []u16, []u32, []u64, []u8, []orm.InfixType {
            true
        }
        else {
            false
        }
    }
}

fn bind_array[T](stmt Stmt, mut c &int, data []T) int {
    mut err := 0
    for element in data {
        tmp_err := bind(stmt, mut c, orm.Primitive(element))
        c++
        if tmp_err != 0 {
            err = tmp_err
            break
        }
    }
    return err
}

// Universal bind function
fn bind(stmt Stmt, mut c &int, data orm.Primitive) int {
    mut err := 0
    match data {
        i8, i16, int, u8, u16, u32, bool {
            err = stmt.bind_int(c, int(data))
        }
        i64, u64 {
            err = stmt.bind_i64(c, i64(data))
        }
        f32, f64 {
            err = stmt.bind_f64(c, f64(data))
        }
        string {
            err = stmt.bind_text(c, data)
        }
        time.Time {
            err = stmt.bind_int(c, int(data.unix()))
        }
        orm.InfixType {
            err = bind(stmt, mut c, data.right)
        }
        orm.Null {
            err = stmt.bind_null(c)
        }
        []orm.Primitive {
            err = bind_array(stmt, mut c, data)
        }
        []bool {
            err = bind_array(stmt, mut c, data)
        }
        []f32 {
            err = bind_array(stmt, mut c, data)
        }
        []f64 {
            err = bind_array(stmt, mut c, data)
        }
        []i16 {
            err = bind_array(stmt, mut c, data)
        }
        []i64 {
            err = bind_array(stmt, mut c, data)
        }
        []i8 {
            err = bind_array(stmt, mut c, data)
        }
        []int {
            err = bind_array(stmt, mut c, data)
        }
        []string {
            err = bind_array(stmt, mut c, data)
        }
        []time.Time {
            err = bind_array(stmt, mut c, data)
        }
        []u16 {
            err = bind_array(stmt, mut c, data)
        }
        []u32 {
            err = bind_array(stmt, mut c, data)
        }
        []u64 {
            err = bind_array(stmt, mut c, data)
        }
        []u8 {
            err = bind_array(stmt, mut c, data)
        }
        []orm.InfixType {
            err = bind_array(stmt, mut c, data)
        }
    }

    return err
}

// Selects column in result and converts it to an orm.Primitive
fn (stmt Stmt) sqlite_select_column(idx int, typ int) !orm.Primitive {
    if typ in orm.nums || typ == -1 {
        return stmt.get_int(idx) or { return orm.Null{} }
    } else if typ in orm.num64 {
        return stmt.get_i64(idx) or { return orm.Null{} }
    } else if typ == typeof[f32]().idx {
        return f32(stmt.get_f64(idx) or { return orm.Null{} })
    } else if typ == typeof[f64]().idx {
        return stmt.get_f64(idx) or { return orm.Null{} }
    } else if typ == orm.type_string {
        if v := stmt.get_text(idx) {
            return v.clone()
        } else {
            return orm.Null{}
        }
    } else if typ == orm.enum_ {
        return stmt.get_i64(idx) or { return orm.Null{} }
    } else if typ == orm.time_ {
        if v := stmt.get_int(idx) {
            return time.unix(v)
        } else {
            return orm.Null{}
        }
    } else {
        return error('Unknown type ${typ}')
    }
}

// Convert type int to sql type string
fn sqlite_type_from_v(typ int) !string {
    return if typ in orm.nums || typ in orm.num64 || typ in [orm.serial, orm.time_, orm.enum_] {
        'INTEGER'
    } else if typ in orm.float {
        'REAL'
    } else if typ == orm.type_string {
        'TEXT'
    } else {
        error('Unknown type ${typ}')
    }
}