// 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.

package driver

import (
	"fmt"
	"io"
	"io/ioutil"
	"os"
	"sync"

	"github.com/golang/protobuf/jsonpb"
	"github.com/golang/protobuf/proto"
	tnProto "go.chromium.org/chromiumos/config/go/api/test/harness/tnull/v1"
	results "go.chromium.org/chromiumos/config/go/api/test/results/v2"
	rtd "go.chromium.org/chromiumos/config/go/api/test/rtd/v1"

	"go.chromium.org/luci/common/errors"
	"go.chromium.org/luci/common/sync/parallel"
)

type progressSinkInternalClient struct {
	config        *rtd.ProgressSinkClientConfig
	driver        *Driver
	failureReason error
}

func (c *progressSinkInternalClient) archiveArtifact(req *rtd.ArchiveArtifactRequest) *rtd.ArchiveArtifactResponse {
	c.failureReason = errors.Reason("'archiveArtifact' Not yet implemented").Err()
	c.printErr(c.failureReason)
	return nil
}

func (c *progressSinkInternalClient) reportLog(req *rtd.ReportLogRequest) *rtd.ReportLogResponse {
	c.failureReason = errors.Reason("'reportLog' Not yet implemented").Err()
	c.printErr(c.failureReason)
	return nil
}

func (c *progressSinkInternalClient) reportResult(req *rtd.ReportResultRequest) *rtd.ReportResultResponse {
	c.failureReason = errors.Reason("'reportResult' Not yet implemented").Err()
	c.printErr(c.failureReason)
	return nil
}

func (c *progressSinkInternalClient) debugLog(req proto.Message, resp proto.Message) *rtd.ReportLogResponse {
	// This form of the method is temporary and serves as a stand-in for an actual RTS connection
	localDebug := c.driver.debugErr
	m := jsonpb.Marshaler{EmitDefaults: true, Indent: "  "}
	fmt.Fprintln(localDebug, "Request:")
	if err := m.Marshal(localDebug, req); err != nil {
		err = errors.Annotate(err, "failed to marshal request:").Err()
		fmt.Fprintln(localDebug, err)
	}
	fmt.Fprintln(localDebug, "Response:")
	if err := m.Marshal(localDebug, resp); err != nil {
		err = errors.Annotate(err, "failed to marshal response:").Err()
		fmt.Fprintln(localDebug, err)
	}
	return nil
}

func (c *progressSinkInternalClient) printErr(err error) {
	// This method is temporary and serves as a stand-in for an actual RTS connection
	c.failureReason = err
	fmt.Fprintln(c.driver.debugErr, err)
}

// Driver is a single-instance object which runs all the operations for a test
type Driver struct {
	artifacts  []*tnProto.MockArtifact
	emitResult sync.Once
	client     *progressSinkInternalClient
	config     *rtd.ProgressSinkClientConfig
	logs       []*tnProto.MockLog
	result     *results.Result
	debugErr   io.Writer
}

func (d *Driver) SetDebugErrDestination(dest io.Writer) {
	d.debugErr = dest
}

// Setup sets config and prepares a result/logs/artifacts. It is called only once.
func (d *Driver) Setup(testName string, setup tnProto.SetupStep) error {
	d.config = setup.Config
	d.client = &progressSinkInternalClient{config: setup.Config, driver: d}
	d.result = setup.Result
	d.logs = setup.Logs
	d.artifacts = setup.Artifacts
	return d.client.failureReason
}

// Archive sends all the stored mock artifacts to the RPC service, in parallel
func (d *Driver) Archive(requestName string) error {
	return parallel.WorkPool(0, func(fchan chan<- func() error) {
		for _, a := range d.artifacts {
			a := a
			fchan <- func() error {
				tmp, err := ioutil.TempFile("", "")
				if err != nil {
					return errors.Annotate(err, "archiving %s", a.Name).Err()
				}
				ioutil.WriteFile(tmp.Name(), a.FileBytes, os.ModePerm)
				req := &rtd.ArchiveArtifactRequest{
					Name:      a.Name,
					Request:   requestName,
					LocalPath: tmp.Name(),
				}
				resp := d.client.archiveArtifact(req)
				d.client.debugLog(req, resp)
				return d.client.failureReason
			}
		}
	})
}

// Log reports all the stored mock logs to the RPC service, in parallel
func (d *Driver) Log(requestName string) error {
	return parallel.WorkPool(0, func(fchan chan<- func() error) {
		for _, l := range d.logs {
			l := l
			for _, m := range l.Messages {
				m := m
				fchan <- func() error {
					req := &rtd.ReportLogRequest{
						Name:    l.Name,
						Request: requestName,
						Data:    []byte(m),
					}
					resp := d.client.reportLog(req)
					d.client.debugLog(req, resp)
					return d.client.failureReason
				}
			}
		}
	})
}

// Result reports the already-stored result to the RPC service
func (d *Driver) Result(requestName string) error {
	var wasFirstTime bool
	d.emitResult.Do(func() {
		req := &rtd.ReportResultRequest{
			Request: requestName,
			Result:  d.result,
		}
		resp := d.client.reportResult(req)
		d.client.debugLog(req, resp)
		wasFirstTime = true
	})
	if !wasFirstTime {
		return errors.Reason("Result cannot be called twice.").Err()
	}
	return d.client.failureReason
}