#!/usr/bin/env python3
# -*- coding: utf-8 -*-"
#
# Copyright 2020 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""Find missing stable and backported mainline fix patches in chromeos."""

from __future__ import print_function

import MySQLdb # pylint: disable=import-error

import common

DEFAULT_MERGED_REASON = 'Fix merged into linux chrome'


def upstream_fixes_for_shas(db, upstream_shas):
    """Returns list of fixer sha's for a given upstream sha.

    TODO(*): remove this after build_ordered_fixes_table_map moved to SQL CTE
    Note: above todo is blocked by migration to MySQL 5.7, once upgraded then we can switch
    """
    upstream_shas = ["\'" + sha + "\'" for sha in upstream_shas]
    c = db.cursor()

    # format string here since we are inserting n elements
    q = """SELECT fixedby_upstream_sha
            FROM upstream_fixes
            WHERE upstream_sha IN ({})""".format(', '.join(upstream_shas))
    c.execute(q)

    return [a[0] for a in c.fetchall()]


def get_fixes_table_primary_key(db, fixes_table, fix_change_id):
    """Retrieves the primary keys from a fixes table using changeid."""
    c = db.cursor(MySQLdb.cursors.DictCursor)

    q = """SELECT kernel_sha, fixedby_upstream_sha
            FROM {fixes_table}
            WHERE fix_change_id = %s""".format(fixes_table=fixes_table)

    c.execute(q, [fix_change_id])
    row = c.fetchone()
    return (row['kernel_sha'], row['fixedby_upstream_sha'])


def get_fix_status_and_changeid(db, fixes_table, kernel_sha, fixedby_upstream_sha):
    """Get branch, fix_change_id, initial_status and status for one or more rows in fixes table."""
    c = db.cursor(MySQLdb.cursors.DictCursor)

    q = """SELECT '{fixes_table}' AS 'table', branch, kernel_sha, fixedby_upstream_sha,
                  fix_change_id, initial_status, status
           FROM {fixes_table}""".format(fixes_table=fixes_table)

    if kernel_sha and fixedby_upstream_sha:
        q += ' WHERE kernel_sha = %s AND fixedby_upstream_sha = %s'
        sha_list = [kernel_sha, fixedby_upstream_sha]
    elif fixedby_upstream_sha:
        q += ' WHERE fixedby_upstream_sha = %s'
        sha_list = [fixedby_upstream_sha]
    else:
        q += ' WHERE kernel_sha = %s'
        sha_list = [kernel_sha]

    c.execute(q, sha_list)
    return c.fetchall()


def get_fix_status_and_changeid_from_list(db, fixes_table, sha_list):
    """Get branch, fix_change_id, initial_status and status for one or more rows in fixes table.

    The SHA or SHAs to identify commits are provided as anonymous SHA list. SHAs may either
    be from the upstream kernel or from the ChromeOS kernel. One or two SHAs must be provided.
    If there is one SHA, it must ieither be from the upstream kernel or from a ChromeOS branch.
    If there are two SHAs, one must be from the upstream kernel, the other must be from a ChromeOS
    branch.
    """
    c = db.cursor(MySQLdb.cursors.DictCursor)
    # find out which SHA is which
    kernel_sha = None
    fixedby_upstream_sha = None
    q = """SELECT sha FROM linux_upstream
            WHERE sha = %s"""
    c.execute(q, [sha_list[0]])
    if c.fetchone():
        # First SHA is upstream SHA
        fixedby_upstream_sha = sha_list[0]
        if len(sha_list) > 1:
            kernel_sha = sha_list[1]
    else:
        kernel_sha = sha_list[0]
        if len(sha_list) > 1:
            fixedby_upstream_sha = sha_list[1]

    return get_fix_status_and_changeid(db, fixes_table, kernel_sha, fixedby_upstream_sha)


def update_change_abandoned(db, fixes_table, kernel_sha, fixedby_upstream_sha, reason=None):
    """Updates fixes_table unique fix row to indicate fix cl has been abandoned.

    Function will only abandon rows in the table which have status OPEN or CONFLICT.
    """
    c = db.cursor()
    q = """UPDATE {fixes_table}
            SET status = 'ABANDONED', close_time = %s, reason = %s
            WHERE kernel_sha = %s
            AND fixedby_upstream_sha = %s
            AND (status = 'OPEN' OR status = 'CONFLICT')""".format(fixes_table=fixes_table)
    close_time = common.get_current_time()
    c.execute(q, [close_time, reason, kernel_sha, fixedby_upstream_sha])
    db.commit()


def update_change_restored(db, fixes_table, kernel_sha, fixedby_upstream_sha, reason=None):
    """Updates fixes_table unique fix row to indicate fix cl has been reopened."""
    rows = get_fix_status_and_changeid(db, fixes_table, kernel_sha, fixedby_upstream_sha)
    row = rows[0]
    status = 'OPEN' if row['fix_change_id'] else row['initial_status']

    c = db.cursor()
    q = """UPDATE {fixes_table}
            SET status = %s, close_time = %s, reason = %s
            WHERE kernel_sha = %s
            AND fixedby_upstream_sha = %s
            AND status = 'ABANDONED'""".format(fixes_table=fixes_table)
    c.execute(q, [status, None, reason, kernel_sha, fixedby_upstream_sha])
    db.commit()


def update_change_merged(db, fixes_table, kernel_sha, fixedby_upstream_sha,
                            reason=DEFAULT_MERGED_REASON):
    """Updates fixes_table unique fix row to indicate fix cl has been merged."""
    c = db.cursor()
    q = """UPDATE {fixes_table}
            SET status = 'MERGED', close_time = %s, reason = %s
            WHERE kernel_sha = %s
            AND fixedby_upstream_sha = %s""".format(fixes_table=fixes_table)
    close_time = common.get_current_time()
    c.execute(q, [close_time, reason, kernel_sha, fixedby_upstream_sha])
    db.commit()


def update_change_status(db, fixes_table, fix_change_id, status):
    """Updates fixes_table with the latest status from Gerrit API.

    This is done to synchronize CL's that are
    abandoned/restored on Gerrit with our database state
    """
    kernel_sha, fixedby_upstream_sha = get_fixes_table_primary_key(db, fixes_table, fix_change_id)
    if status == common.Status.OPEN:
        update_change_restored(db, fixes_table, kernel_sha, fixedby_upstream_sha)
    elif status == common.Status.ABANDONED:
        update_change_abandoned(db, fixes_table, kernel_sha, fixedby_upstream_sha)
    elif status == common.Status.MERGED:
        update_change_merged(db, fixes_table, kernel_sha, fixedby_upstream_sha)
    else:
        raise ValueError('Change should be either OPEN, ABANDONED, or MERGED')


def update_conflict_to_open(db, fixes_table, kernel_sha, fixedby_upstream_sha, fix_change_id):
    """Updates fixes_table to represent an open change that previously resulted in conflict."""
    c = db.cursor()
    reason = 'Patch applies cleanly after originally conflicting.'
    q = """UPDATE {fixes_table}
            SET status = 'OPEN', fix_change_id = %s, reason = %s
            WHERE kernel_sha = %s
            AND fixedby_upstream_sha = %s""".format(fixes_table=fixes_table)
    c.execute(q, [fix_change_id, reason, kernel_sha, fixedby_upstream_sha])
    db.commit()