"""Functions that help you work with QMK keymaps.
"""
import os

import qmk.path

# The `keymap.c` template to use when a keyboard doesn't have its own
DEFAULT_KEYMAP_C = """#include QMK_KEYBOARD_H

/* THIS FILE WAS GENERATED!
 *
 * This file was generated by qmk-compile-json. You may or may not want to
 * edit it directly.
 */

const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
__KEYMAP_GOES_HERE__
};
"""


def template(keyboard):
    """Returns the `keymap.c` template for a keyboard.

    If a template exists in `keyboards/<keyboard>/templates/keymap.c` that
    text will be used instead of `DEFAULT_KEYMAP_C`.

    Args:
        keyboard
            The keyboard to return a template for.
    """
    template_name = 'keyboards/%s/templates/keymap.c' % keyboard

    if os.path.exists(template_name):
        with open(template_name, 'r') as fd:
            return fd.read()

    return DEFAULT_KEYMAP_C


def generate(keyboard, layout, layers):
    """Returns a keymap.c for the specified keyboard, layout, and layers.

    Args:
        keyboard
            The name of the keyboard

        layout
            The LAYOUT macro this keymap uses.

        layers
            An array of arrays describing the keymap. Each item in the inner array should be a string that is a valid QMK keycode.
    """
    layer_txt = []
    for layer_num, layer in enumerate(layers):
        if layer_num != 0:
            layer_txt[-1] = layer_txt[-1] + ','
        layer_keys = ', '.join(layer)
        layer_txt.append('\t[%s] = %s(%s)' % (layer_num, layout, layer_keys))

    keymap = '\n'.join(layer_txt)
    keymap_c = template(keyboard)

    return keymap_c.replace('__KEYMAP_GOES_HERE__', keymap)


def write(keyboard, keymap, layout, layers):
    """Generate the `keymap.c` and write it to disk.

    Returns the filename written to.

    Args:
        keyboard
            The name of the keyboard

        keymap
            The name of the keymap

        layout
            The LAYOUT macro this keymap uses.

        layers
            An array of arrays describing the keymap. Each item in the inner array should be a string that is a valid QMK keycode.
    """
    keymap_c = generate(keyboard, layout, layers)
    keymap_path = qmk.path.keymap(keyboard)
    keymap_dir = os.path.join(keymap_path, keymap)
    keymap_file = os.path.join(keymap_dir, 'keymap.c')

    if not os.path.exists(keymap_dir):
        os.makedirs(keymap_dir)

    with open(keymap_file, 'w') as keymap_fd:
        keymap_fd.write(keymap_c)

    return keymap_file