// Copyright 2020 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

package main

import (
	"context"
	"fmt"
	"time"

	"github.com/maruel/subcommands"
	"go.chromium.org/luci/auth"
	"go.chromium.org/luci/common/retry"
	"go.chromium.org/luci/common/retry/transient"
)

func cmdTriggerCQ(authOpts auth.Options) *subcommands.Command {
	return &subcommands.Command{
		UsageLine: "trigger-cq -host <gerrit-host> -project <gerrit-project> -change-num <change-num> [-wait] [-timeout <timeout>] [-dryrun]",
		ShortDesc: "Trigger CQ on a CL.",
		LongDesc:  "Trigger CQ on a CL.",
		CommandRun: func() subcommands.CommandRun {
			c := &triggerCQRun{}
			c.Init(authOpts)
			return c
		},
	}
}

type triggerCQRun struct {
	commonFlags
	changeNum int64
	wait      bool
	timeout   time.Duration
	dryRun    bool
}

func (c *triggerCQRun) Init(defaultAuthOpts auth.Options) {
	c.commonFlags.Init(defaultAuthOpts)
	c.Flags.Int64Var(&c.changeNum, "change-num", 0, "Gerrit change number.")
	c.Flags.BoolVar(&c.wait, "wait", true, "If set, to wait for CQ to complete.")
	c.Flags.DurationVar(&c.timeout, "timeout", 0, "Wait this long for CQ to finish; indefinite if not set.")
	c.Flags.BoolVar(&c.dryRun, "dryrun", false, "If set, apply CQ+1; otherwise apply CQ+2.")
}

func (c *triggerCQRun) Parse(a subcommands.Application, args []string) error {
	if err := c.commonFlags.Parse(); err != nil {
		return err
	}
	if c.changeNum == 0 {
		return fmt.Errorf("-change-num is required")
	}
	return nil
}

func (c *triggerCQRun) main(a subcommands.Application) error {
	ctx := context.Background()
	client, err := newGerritClient(ctx, c.gerritHost, c.gerritProject, c.parsedAuthOpts)
	if err != nil {
		return err
	}
	if err := client.setCQLabel(ctx, c.changeNum, c.dryRun); err != nil {
		return err
	}
	if !c.wait {
		return nil
	}
	// Check for CQ completion once a minute.
	retryPolicy := transient.Only(func() retry.Iterator {
		return &retry.ExponentialBackoff{
			Limited: retry.Limited{
				Delay:   time.Minute,
				Retries: -1,
			},
			Multiplier: 1,
		}
	})
	var cancel context.CancelFunc
	if c.timeout > 0 {
		ctx, cancel = context.WithTimeout(ctx, c.timeout)
		defer cancel()
	}
	return retry.Retry(ctx, retryPolicy, func() error {
		return client.checkCQCompletion(ctx, c.changeNum)
	}, nil)
}

func (c *triggerCQRun) Run(a subcommands.Application, args []string, env subcommands.Env) int {
	if err := c.Parse(a, args); err != nil {
		fmt.Fprintf(a.GetErr(), "%s: %s\n", a.GetName(), err)
		return 1
	}

	if err := c.main(a); err != nil {
		fmt.Fprintf(a.GetErr(), "%s: %s\n", a.GetName(), err)
		return 1
	}
	return 0
}