package cli

import (
	"fmt"
	"os"
	"time"

	"github.com/spf13/cobra"

	"github.com/coder/coder/coderd/autobuild/schedule"
	"github.com/coder/coder/codersdk"
)

const autostartDescriptionLong = `To have your workspace build automatically at a regular time you can enable autostart.
When enabling autostart, provide the minute, hour, and day(s) of week.
The default schedule is at 09:00 in your local timezone (TZ env, UTC by default).
`

func autostart() *cobra.Command {
	autostartCmd := &cobra.Command{
		Annotations: workspaceCommand,
		Use:         "autostart enable <workspace>",
		Short:       "schedule a workspace to automatically start at a regular time",
		Long:        autostartDescriptionLong,
		Example:     "coder autostart enable my-workspace --minute 30 --hour 9 --days 1-5 --tz Europe/Dublin",
	}

	autostartCmd.AddCommand(autostartShow())
	autostartCmd.AddCommand(autostartEnable())
	autostartCmd.AddCommand(autostartDisable())

	return autostartCmd
}

func autostartShow() *cobra.Command {
	cmd := &cobra.Command{
		Use:  "show <workspace_name>",
		Args: cobra.ExactArgs(1),
		RunE: func(cmd *cobra.Command, args []string) error {
			client, err := createClient(cmd)
			if err != nil {
				return err
			}

			workspace, err := namedWorkspace(cmd, client, args[0])
			if err != nil {
				return err
			}

			if workspace.AutostartSchedule == nil || *workspace.AutostartSchedule == "" {
				_, _ = fmt.Fprintf(cmd.OutOrStdout(), "not enabled\n")
				return nil
			}

			validSchedule, err := schedule.Weekly(*workspace.AutostartSchedule)
			if err != nil {
				// This should never happen.
				_, _ = fmt.Fprintf(cmd.OutOrStdout(), "Invalid autostart schedule %q for workspace %s: %s\n", *workspace.AutostartSchedule, workspace.Name, err.Error())
				return nil
			}

			next := validSchedule.Next(time.Now())
			loc, _ := time.LoadLocation(validSchedule.Timezone())

			_, _ = fmt.Fprintf(cmd.OutOrStdout(),
				"schedule: %s\ntimezone: %s\nnext:     %s\n",
				validSchedule.Cron(),
				validSchedule.Timezone(),
				next.In(loc),
			)

			return nil
		},
	}
	return cmd
}

func autostartEnable() *cobra.Command {
	// yes some of these are technically numbers but the cron library will do that work
	var autostartMinute string
	var autostartHour string
	var autostartDayOfWeek string
	var autostartTimezone string
	cmd := &cobra.Command{
		Use:  "enable <workspace_name> <schedule>",
		Args: cobra.ExactArgs(1),
		RunE: func(cmd *cobra.Command, args []string) error {
			client, err := createClient(cmd)
			if err != nil {
				return err
			}

			spec := fmt.Sprintf("CRON_TZ=%s %s %s * * %s", autostartTimezone, autostartMinute, autostartHour, autostartDayOfWeek)
			validSchedule, err := schedule.Weekly(spec)
			if err != nil {
				return err
			}

			workspace, err := namedWorkspace(cmd, client, args[0])
			if err != nil {
				return err
			}

			err = client.UpdateWorkspaceAutostart(cmd.Context(), workspace.ID, codersdk.UpdateWorkspaceAutostartRequest{
				Schedule: &spec,
			})
			if err != nil {
				return err
			}

			_, _ = fmt.Fprintf(cmd.OutOrStdout(), "\nThe %s workspace will automatically start at %s.\n\n", workspace.Name, validSchedule.Next(time.Now()))

			return nil
		},
	}

	cmd.Flags().StringVar(&autostartMinute, "minute", "0", "autostart minute")
	cmd.Flags().StringVar(&autostartHour, "hour", "9", "autostart hour")
	cmd.Flags().StringVar(&autostartDayOfWeek, "days", "1-5", "autostart day(s) of week")
	tzEnv := os.Getenv("TZ")
	if tzEnv == "" {
		tzEnv = "UTC"
	}
	cmd.Flags().StringVar(&autostartTimezone, "tz", tzEnv, "autostart timezone")
	return cmd
}

func autostartDisable() *cobra.Command {
	return &cobra.Command{
		Use:  "disable <workspace_name>",
		Args: cobra.ExactArgs(1),
		RunE: func(cmd *cobra.Command, args []string) error {
			client, err := createClient(cmd)
			if err != nil {
				return err
			}

			workspace, err := namedWorkspace(cmd, client, args[0])
			if err != nil {
				return err
			}

			err = client.UpdateWorkspaceAutostart(cmd.Context(), workspace.ID, codersdk.UpdateWorkspaceAutostartRequest{
				Schedule: nil,
			})
			if err != nil {
				return err
			}

			_, _ = fmt.Fprintf(cmd.OutOrStdout(), "\nThe %s workspace will no longer automatically start.\n\n", workspace.Name)

			return nil
		},
	}
}