module main

import config
import db.pg
import os

type GitlyDb = pg.DB

fn connect_db(conf config.Config) !GitlyDb {
    if conninfo := first_env_opt(['GITLY_DB_CONNINFO', 'DATABASE_URL'], conf.pg.conninfo) {
        return GitlyDb(pg.connect_with_conninfo(conninfo)!)
    }
    return GitlyDb(pg.connect(
        host:     first_env(['GITLY_DB_HOST', 'PGHOST'], conf.pg.host)
        port:     first_int_env(['GITLY_DB_PORT', 'PGPORT'], conf.pg.port)
        dbname:   first_env(['GITLY_DB_NAME', 'PGDATABASE'], conf.pg.dbname)
        user:     first_env(['GITLY_DB_USER', 'PGUSER'], conf.pg.user)
        password: first_env(['GITLY_DB_PASSWORD', 'PGPASSWORD'], conf.pg.password)
    )!)
}

fn db_backend_name() string {
    return 'postgres'
}

fn db_exec_values(db &GitlyDb, query string) ![][]string {
    rows := db.exec_no_null(query)!
    mut values := [][]string{cap: rows.len}
    for row in rows {
        values << row.vals.clone()
    }
    return values
}

fn db_last_insert_id(db &GitlyDb) int {
    rows := db.exec_no_null('SELECT lastval()') or { return 0 }
    if rows.len > 0 && rows[0].vals.len > 0 {
        return rows[0].vals[0].int()
    }
    return 0
}

fn db_column_exists(db &GitlyDb, table_name string, column_name string) !bool {
    rows := db_exec_values(db,
        'select column_name from information_schema.columns where table_name = ${sql_literal(table_name.to_lower())} and column_name = ${sql_literal(column_name)}')!
    return rows.len > 0
}

fn db_bool_column_type() string {
    return 'BOOLEAN NOT NULL DEFAULT false'
}

fn first_env(keys []string, fallback string) string {
    for key in keys {
        value := os.getenv(key)
        if value != '' {
            return value
        }
    }
    return fallback
}

fn first_env_opt(keys []string, fallback string) ?string {
    value := first_env(keys, fallback)
    if value == '' {
        return none
    }
    return value
}

fn first_int_env(keys []string, fallback int) int {
    for key in keys {
        value := os.getenv(key)
        if value != '' {
            return value.int()
        }
    }
    return fallback
}