package main

import (
	"context"
	"fmt"
	"os"
	"os/signal"
	"strconv"
	"strings"
	"time"

	"github.com/google/go-github/v43/github"
	"golang.org/x/oauth2"
)

func handleInterrupt(client *github.Client, ctx context.Context, apprv *approvalEnvironment) {
	newState := "closed"
	closeComment := "Workflow cancelled, closing issue."
	fmt.Println(closeComment)
	_, _, err := client.Issues.CreateComment(ctx, apprv.repoOwner, apprv.repo, apprv.approvalIssueNumber, &github.IssueComment{
		Body: &closeComment,
	})
	if err != nil {
		fmt.Printf("error commenting on issue: %v\n", err)
		return
	}
	_, _, err = client.Issues.Edit(ctx, apprv.repoOwner, apprv.repo, apprv.approvalIssueNumber, &github.IssueRequest{State: &newState})
	if err != nil {
		fmt.Printf("error closing issue: %v\n", err)
		return
	}
}

func newCommentLoopChannel(ctx context.Context, apprv *approvalEnvironment, client *github.Client, approvers []string, minimumApprovals int) chan int {
	channel := make(chan int)
	go func() {
		for {
			comments, _, err := client.Issues.ListComments(ctx, apprv.repoOwner, apprv.repo, apprv.approvalIssueNumber, &github.IssueListCommentsOptions{})
			if err != nil {
				fmt.Printf("error getting comments: %v\n", err)
				channel <- 1
				close(channel)
			}

			approved, err := approvalFromComments(comments, approvers, minimumApprovals)
			if err != nil {
				fmt.Printf("error getting approval from comments: %v\n", err)
				channel <- 1
				close(channel)
			}
			fmt.Printf("Workflow status: %s\n", approved)
			switch approved {
			case approvalStatusApproved:
				newState := "closed"
				closeComment := "All approvers have approved, continuing workflow and closing this issue."
				_, _, err := client.Issues.CreateComment(ctx, apprv.repoOwner, apprv.repo, apprv.approvalIssueNumber, &github.IssueComment{
					Body: &closeComment,
				})
				if err != nil {
					fmt.Printf("error commenting on issue: %v\n", err)
					channel <- 1
					close(channel)
				}
				_, _, err = client.Issues.Edit(ctx, apprv.repoOwner, apprv.repo, apprv.approvalIssueNumber, &github.IssueRequest{State: &newState})
				if err != nil {
					fmt.Printf("error closing issue: %v\n", err)
					channel <- 1
					close(channel)
				}
				channel <- 0
				fmt.Println("Workflow manual approval completed")
				close(channel)
			case approvalStatusDenied:
				newState := "closed"
				closeComment := "Request denied. Closing issue and failing workflow."
				_, _, err := client.Issues.CreateComment(ctx, apprv.repoOwner, apprv.repo, apprv.approvalIssueNumber, &github.IssueComment{
					Body: &closeComment,
				})
				if err != nil {
					fmt.Printf("error commenting on issue: %v\n", err)
					channel <- 1
					close(channel)
				}
				_, _, err = client.Issues.Edit(ctx, apprv.repoOwner, apprv.repo, apprv.approvalIssueNumber, &github.IssueRequest{State: &newState})
				if err != nil {
					fmt.Printf("error closing issue: %v\n", err)
					channel <- 1
					close(channel)
				}
				channel <- 1
				close(channel)
			}

			time.Sleep(pollingInterval)
		}
	}()
	return channel
}

func newGithubClient(ctx context.Context) *github.Client {
	token := os.Getenv(envVarToken)
	ts := oauth2.StaticTokenSource(
		&oauth2.Token{AccessToken: token},
	)
	tc := oauth2.NewClient(ctx, ts)
	return github.NewClient(tc)
}

func main() {
	repoFullName := os.Getenv(envVarRepoFullName)
	runID, err := strconv.Atoi(os.Getenv(envVarRunID))
	if err != nil {
		fmt.Printf("error getting runID: %v\n", err)
		os.Exit(1)
	}
	repoOwner := os.Getenv(envVarRepoOwner)

	ctx := context.Background()
	client := newGithubClient(ctx)

	requiredApproversRaw := os.Getenv(envVarApprovers)
	fmt.Printf("Required approvers: %s\n", requiredApproversRaw)
	approvers := strings.Split(requiredApproversRaw, ",")

	minimumApprovalsRaw := os.Getenv(envVarMinimumApprovals)
	minimumApprovals := len(approvers)
	if minimumApprovalsRaw != "" {
		minimumApprovals, err = strconv.Atoi(minimumApprovalsRaw)
		if err != nil {
			fmt.Printf("error parsing minimum number of approvals: %v\n", err)
			os.Exit(1)
		}
	}

	if minimumApprovals > len(approvers) {
		fmt.Printf("error: minimum required approvals (%v) is greater than the total number of approvers (%v)\n", minimumApprovals, len(approvers))
		os.Exit(1)
	}

	apprv, err := newApprovalEnvironment(client, repoFullName, repoOwner, runID, approvers, minimumApprovals)
	if err != nil {
		fmt.Printf("error creating approval environment: %v\n", err)
		os.Exit(1)
	}

	err = apprv.createApprovalIssue(ctx)
	if err != nil {
		fmt.Printf("error creating issue: %v", err)
		os.Exit(1)
	}

	killSignalChannel := make(chan os.Signal, 1)
	signal.Notify(killSignalChannel, os.Interrupt)

	commentLoopChannel := newCommentLoopChannel(ctx, apprv, client, approvers, minimumApprovals)

	select {
	case exitCode := <-commentLoopChannel:
		os.Exit(exitCode)
	case _ = <-killSignalChannel:
		handleInterrupt(client, ctx, apprv)
		os.Exit(1)
	}
}