package vcs

import (
	"bytes"
	"context"
	"encoding/json"
	"errors"
	"io"
	"io/ioutil"
	"os"
	"os/exec"
	"strconv"
	"strings"
	"time"
)

type cmdVCS struct {
	log    logger
	module string
	cmd    string
}

func NewCommand(l logger, cmd string, module string) VCS {
	return &cmdVCS{log: l, cmd: cmd, module: module}
}

func (c *cmdVCS) List(ctx context.Context) ([]Version, error) {
	b, err := c.exec(ctx, "MODULE="+c.module, "ACTION=list", "VERSION=latest", "FILEPATH="+c.module+"/@v/list")
	if err != nil {
		return nil, err
	}
	versions := []Version{}
	for _, line := range strings.Split(string(b), "\n") {
		versions = append(versions, Version(line))
	}
	return versions, nil
}

func (c *cmdVCS) Timestamp(ctx context.Context, version Version) (time.Time, error) {
	b, err := c.exec(ctx, "MODULE="+c.module, "ACTION=timestamp", "VERSION="+version.String(),
		"FILEPATH="+c.module+"/@v/"+version.String()+".info")
	if err != nil {
		return time.Time{}, err
	}
	info := struct {
		Version string
		Time    time.Time
	}{}
	if json.Unmarshal(b, &info) == nil {
		return info.Time, nil
	}
	if t, err := time.Parse(time.RFC3339, string(b)); err == nil {
		return t, nil
	}
	if sec, err := strconv.ParseInt(string(b), 10, 64); err == nil {
		return time.Unix(sec, 0), nil
	}
	return time.Time{}, errors.New("unknown time format")
}

func (c *cmdVCS) Zip(ctx context.Context, version Version) (io.ReadCloser, error) {
	b, err := c.exec(ctx, "MODULE="+c.module, "ACTION=zip", "VERSION="+version.String(),
		"FILEPATH="+c.module+"/@v/"+version.String()+".zip")
	if err != nil {
		return nil, err
	}
	return ioutil.NopCloser(bytes.NewReader(b)), nil
}

func (c *cmdVCS) exec(ctx context.Context, env ...string) ([]byte, error) {
	cmd := exec.Command("sh", "-c", c.cmd)
	cmd.Env = append(os.Environ(), env...)
	cmd.Stderr = os.Stderr
	return cmd.Output()
}