package pr

import (
	"crypto/tls"
	"encoding/json"
	"fmt"
	"io/ioutil"
	"net/http"
	"net/url"
	"os"
	"path"
	"sort"
	"strconv"
	"strings"
	"text/tabwriter"

	"git.sr.ht/~avanier/gitea-resource/util"
)

// List returns a slice of PRs
func List(stdinPayload util.STDINPayload) {
	var (
		err            error
		stdoutVersions []stdoutVersion
	)

	if stdinPayload.Source.SkipSSLVerification {
		http.DefaultTransport.(*http.Transport).TLSClientConfig = &tls.Config{InsecureSkipVerify: true}
	}

	client := &http.Client{}

	req, err := http.NewRequest("GET", composeAllPrURL(stdinPayload.Source), nil)

	if !stdinPayload.Source.Insecure && len(stdinPayload.Source.AccessToken) > 0 {
		req.Header.Add("Authorization", stdinPayload.Source.AccessToken)
	}

	response, err := client.Do(req)
	util.CheckResponse(response)

	/*
		CAVEAT EMPTOR

		This does not page. So, for some reason if you have more than 50 PRs addeed
		since you last checked, or you run this for the first time, and you set version
		to `every`, this will only show the 50 first. You can either change Gitea's
		number of API items returned, or create a PR a pager here.

		https://docs.gitea.io/en-us/api-usage/
	*/

	if err != nil {
		util.HandleError(err)
	}

	data, _ := ioutil.ReadAll(response.Body)

	prs := []pr{} // Slice of PRs
	err = json.Unmarshal(data, &prs)

	if err != nil {
		util.HandleError(err)
	}

	fmt.Fprintf(os.Stderr, "prs returned: %d\n", len(prs))
	fmt.Fprintf(os.Stderr, "minimum version: %s\n", stdinPayload.Version.Number)

	prs = filterPRs(prs, stdinPayload.Version.Number)
	prs = sortPRs(prs)

	table := tabwriter.NewWriter(os.Stderr, 0, 0, 1, ' ', tabwriter.TabIndent)
	header := []string{
		"Number",
		"Url",
		"Title",
		"Creator",
		"Date Created",
		"Base Ref",
		"Head Ref",
	}

	if len(prs) > 0 {
		fmt.Fprintln(table, strings.Join(header, "\t"))
	} else {
		fmt.Fprintln(os.Stderr, "no prs detected beyond the last known version")
	}

	for ind, onePr := range prs {
		stdoutVersions = append(stdoutVersions, stdoutVersion{Ref: strconv.Itoa(int(onePr.Number))})

		if ind == 0 {
			fmt.Printf("\n")
		}

		lineElems := []string{
			fmt.Sprint(onePr.Number),
			onePr.URL,
			onePr.Title,
			extractUser(onePr),
			onePr.Created,
			onePr.Base.Ref,
			onePr.Head.Ref,
		}

		fmt.Fprintln(table, strings.Join(lineElems, "\t"))
	}

	err = table.Flush()

	if err != nil {
		util.HandleError(err)
	}

	stdoutData, err := json.MarshalIndent(stdoutVersions, "", "    ")

	if err != nil {
		util.HandleError(err)
	}

	fmt.Fprintln(os.Stdout, string(stdoutData))
}

func composeAllPrURL(sourceConfig util.SourceConfig) string {
	urlString := &url.URL{}

	if sourceConfig.Insecure {
		urlString.Scheme = "http"
	} else {
		urlString.Scheme = "https"
	}

	urlString.Host = strings.Join([]string{
		sourceConfig.Hostname,
		sourceConfig.Port},
		":",
	)

	urlPath := path.Join(
		"api",
		"v1",
		"repos",
		sourceConfig.Owner,
		sourceConfig.Repo,
		"pulls",
	)

	urlString.Path = urlPath

	queryString := url.Values{}
	queryString.Set("state", "open")
	queryString.Set("sort", "oldest")

	urlString.RawQuery = queryString.Encode()

	return urlString.String()
}

func composeSinglePrURL(source util.STDINPayload) string {
	urlString := &url.URL{}

	if source.Source.Insecure {
		urlString.Scheme = "http"
	} else {
		urlString.Scheme = "https"
	}

	urlString.Host = strings.Join([]string{
		source.Source.Hostname,
		source.Source.Port},
		":",
	)

	urlPath := path.Join(
		"api",
		"v1",
		"repos",
		source.Source.Owner,
		source.Source.Repo,
		"pulls",
		source.Version.Number,
	)

	urlString.Path = urlPath

	return urlString.String()
}

func extractUser(onePr pr) string {
	var user string

	if onePr.User.FullName != "" {
		user = onePr.User.FullName
	} else {
		user = onePr.User.Username
	}

	return user
}

func sortPRs(prs []pr) []pr {
	sort.SliceStable(prs, func(leftInd, rightInd int) bool {
		return prs[leftInd].Number < prs[rightInd].Number
	})

	return prs
}

func filterPRs(prs []pr, minVersStr string) []pr {
	filteredPRs := []pr{}

	minVer, err := strconv.ParseInt(minVersStr, 10, 64)

	if err != nil {
		util.HandleError(err)
	}

	for _, onePR := range prs {
		if int64(onePR.Number) > minVer {
			filteredPRs = append(filteredPRs, onePR)
		}
	}

	return filteredPRs
}

// Get fetches the raw json of the PR object from the API and outputs it to a file
func Get(stdinPayload util.STDINPayload, dest string) {
	var (
		err    error
		thisPR pr
	)

	if stdinPayload.Source.SkipSSLVerification {
		http.DefaultTransport.(*http.Transport).TLSClientConfig = &tls.Config{InsecureSkipVerify: true}
	}

	client := &http.Client{}

	req, err := http.NewRequest("GET", composeSinglePrURL(stdinPayload), nil)

	if err != nil {
		util.HandleError(err)
	}

	if !stdinPayload.Source.Insecure && len(stdinPayload.Source.AccessToken) > 0 {
		req.Header.Add("Authorization", stdinPayload.Source.AccessToken)
	}

	response, err := client.Do(req)
	util.CheckResponse(response)

	data, _ := ioutil.ReadAll(response.Body)
	err = json.Unmarshal(data, &thisPR)

	if err != nil {
		util.HandleError(err)
	}

	metadataPayload := metadata{
		Number:    strconv.Itoa(int(thisPR.Number)),
		Title:     thisPR.Title,
		Base:      thisPR.Base.Ref,
		Head:      thisPR.Head.Ref,
		CreatedAt: thisPR.Created,
		CreatedBy: extractUser(thisPR),
	}

	stdoutPayload := getStdout{
		Version: stdoutVersion{
			Ref: strconv.Itoa(int(thisPR.Number)),
		},
		Metadata: metadataPayload,
	}

	stdoutData, err := json.MarshalIndent(stdoutPayload, "", "    ")
	fmt.Fprintln(os.Stdout, string(stdoutData))

	rawDestFile := path.Join(
		dest,
		"pr.json",
	)

	metaDestFile := path.Join(
		dest,
		"metadata.json",
	)

	err = ioutil.WriteFile(rawDestFile, data, 0644)

	if err != nil {
		util.HandleError(err)
	}

	fmt.Fprintf(os.Stderr, "raw data written to %s\n", rawDestFile)

	err = ioutil.WriteFile(metaDestFile, stdoutData, 0644)

	if err != nil {
		util.HandleError(err)
	}

	fmt.Fprintf(os.Stderr, "resource metadata written to %s\n", metaDestFile)

}