// Copyright 2016-2018, Pulumi Corporation.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package cmd

import (
	"fmt"
	"sort"
	"strconv"

	"github.com/dustin/go-humanize"
	"github.com/pkg/errors"
	"github.com/spf13/cobra"

	"github.com/pulumi/pulumi/pkg/backend"
	"github.com/pulumi/pulumi/pkg/backend/display"
	"github.com/pulumi/pulumi/pkg/backend/httpstate"
	"github.com/pulumi/pulumi/pkg/backend/state"
	"github.com/pulumi/pulumi/pkg/tokens"
	"github.com/pulumi/pulumi/pkg/util/cmdutil"
	"github.com/pulumi/pulumi/pkg/workspace"
)

func newStackLsCmd() *cobra.Command {
	var allStacks bool
	var jsonOut bool
	cmd := &cobra.Command{
		Use:   "ls",
		Short: "List all known stacks",
		Args:  cmdutil.NoArgs,
		Run: cmdutil.RunFunc(func(cmd *cobra.Command, args []string) error {
			var packageFilter *tokens.PackageName
			if !allStacks {
				// Ensure we are in a project; if not, we will fail.
				projPath, err := workspace.DetectProjectPath()
				if err != nil {
					return errors.Wrapf(err, "could not detect current project")
				} else if projPath == "" {
					return errors.New("no Pulumi.yaml found; please run this command in a project directory")
				}

				proj, err := workspace.LoadProject(projPath)
				if err != nil {
					return errors.Wrap(err, "could not load current project")
				}
				packageFilter = &proj.Name
			}

			// Get the current backend.
			b, err := currentBackend(display.Options{Color: cmdutil.GetGlobalColorization()})
			if err != nil {
				return err
			}

			// Get the current stack so we can print a '*' next to it.
			var current string
			if s, _ := state.CurrentStack(commandContext(), b); s != nil {
				// If we couldn't figure out the current stack, just don't print the '*' later on instead of failing.
				current = s.Ref().String()
			}

			// List all of the stacks available.
			stackSummaries, err := b.ListStacks(commandContext(), packageFilter)
			if err != nil {
				return err
			}
			// Sort by stack name.
			sort.Slice(stackSummaries, func(i, j int) bool {
				return stackSummaries[i].Name().String() < stackSummaries[j].Name().String()
			})

			if jsonOut {
				return formatJSON(b, current, stackSummaries)
			}

			return formatConsole(b, current, stackSummaries)
		}),
	}
	cmd.PersistentFlags().BoolVarP(
		&jsonOut, "json", "j", false, "Emit outputs as JSON")
	cmd.PersistentFlags().BoolVarP(
		&allStacks, "all", "a", false, "List all stacks instead of just stacks for the current project")

	return cmd
}

// stackSummaryJSON is the shape of the --json output of this command. When --json is passed, we print an array
// of stackSummaryJSON objects.  While we can add fields to this structure in the future, we should not change
// existing fields.
type stackSummaryJSON struct {
	Name          string `json:"name"`
	Current       bool   `json:"current"`
	LastUpdate    string `json:"lastUpdate,omitEmpty"`
	ResourceCount *int   `json:"resourceCount,omitEmpty"`
	URL           string `json:"url,omitEmpty"`
}

func formatJSON(b backend.Backend, currentStack string, stackSummaries []backend.StackSummary) error {
	output := make([]stackSummaryJSON, len(stackSummaries))
	for idx, summary := range stackSummaries {
		summaryJSON := stackSummaryJSON{
			Name:          summary.Name().String(),
			ResourceCount: summary.ResourceCount(),
			Current:       summary.Name().String() == currentStack,
		}

		if summary.LastUpdate() != nil {
			summaryJSON.LastUpdate = summary.LastUpdate().UTC().Format(timeFormat)
		}

		if httpBackend, ok := b.(httpstate.Backend); ok {
			if consoleURL, err := httpBackend.StackConsoleURL(summary.Name()); err == nil {
				summaryJSON.URL = consoleURL
			}
		}

		output[idx] = summaryJSON
	}

	return printJSON(output)
}

func formatConsole(b backend.Backend, currentStack string, stackSummaries []backend.StackSummary) error {
	_, showURLColumn := b.(httpstate.Backend)

	// Devote 48 characters to the name width, unless there is a longer name.
	maxName := 47
	for _, summary := range stackSummaries {
		name := summary.Name().String()
		if len(name) > maxName {
			maxName = len(name)
		}
	}
	maxName++ // Account for adding the '*' to the currently selected stack.

	// Header string and formatting options to align columns.
	formatDirective := "%-" + strconv.Itoa(maxName) + "s %-24s %-18s"
	headers := []interface{}{"NAME", "LAST UPDATE", "RESOURCE COUNT"}
	if showURLColumn {
		formatDirective += " %s"
		headers = append(headers, "URL")
	}
	formatDirective = formatDirective + "\n"

	fmt.Printf(formatDirective, headers...)
	for _, summary := range stackSummaries {
		const none = "n/a"

		// Name column
		name := summary.Name().String()
		if name == currentStack {
			name += "*"
		}

		// Last update column
		lastUpdate := none
		if stackLastUpdate := summary.LastUpdate(); stackLastUpdate != nil {
			lastUpdate = humanize.Time(*stackLastUpdate)
		}

		// ResourceCount column
		resourceCount := none
		if stackResourceCount := summary.ResourceCount(); stackResourceCount != nil {
			resourceCount = strconv.Itoa(*stackResourceCount)
		}

		// Render the columns.
		values := []interface{}{name, lastUpdate, resourceCount}
		if showURLColumn {
			url := none
			if httpBackend, ok := b.(httpstate.Backend); ok {
				if consoleURL, err := httpBackend.StackConsoleURL(summary.Name()); err == nil {
					url = consoleURL
				}
			}
			values = append(values, url)
		}

		fmt.Printf(formatDirective, values...)
	}

	return nil
}