package main

import (
	"errors"
	"fmt"
	"io"
	"os/exec"
	"strings"
	"time"
)

func GetCommitHash(hashfmt string) (string, error) {
	gitCmd := exec.Command("git", "log", "-n", "1", "--pretty=format:"+hashfmt)
	gitCmd.Dir = ModulePath

	stdout, err := gitCmd.StdoutPipe()
	if err != nil {
		return "", err
	}

	if err := gitCmd.Start(); err != nil {
		return "", err
	}

	hashData, err := io.ReadAll(stdout)
	if err != nil {
		return "", err
	}

	if err := gitCmd.Wait(); err != nil {
		return "", err
	}

	trimmedHash := strings.TrimSpace(string(hashData))
	if trimmedHash == "" {
		return "", errors.New("no valid hash found")
	}

	return trimmedHash, nil
}

func GetVersionTag() (string, error) {
	gitCmd := exec.Command("git", "log", "-n", "1", "--pretty=format:%(describe:tags)")
	gitCmd.Dir = ModulePath

	stdout, err := gitCmd.StdoutPipe()
	if err != nil {
		return "", err
	}

	if err := gitCmd.Start(); err != nil {
		return "", err
	}

	tagData, err := io.ReadAll(stdout)
	if err != nil {
		return "", err
	}

	if err := gitCmd.Wait(); err != nil {
		return "", err
	}

	trimmedTag := strings.TrimSpace(string(tagData))
	if trimmedTag == "" {
		return "", errors.New("no valid version tag found")
	}

	return trimmedTag, nil
}

func WorkTreeChanged() bool {
	gitCmd := exec.Command("git", "status", "--porcelain")
	gitCmd.Dir = ModulePath

	stdout, err := gitCmd.StdoutPipe()
	if err != nil {
		return false
	}

	if err := gitCmd.Start(); err != nil {
		return false
	}

	data, err := io.ReadAll(stdout)
	if err != nil {
		return false
	}

	if err := gitCmd.Wait(); err != nil {
		return false
	}

	return len(data) != 0
}

func GatherMetaData() {
	if !WorkTreeChanged() {
		VersionTag, _ = GetVersionTag()
		CommitHash, _ = GetCommitHash("%H")
	} else {
		hash, _ := GetCommitHash("%h")
		VersionTag = fmt.Sprintf("(devel-%s)", hash)
	}

	BuildTime = time.Now().Format(time.RFC3339)
}

func BuildLdFlags(os, arch string) string {
	b := &strings.Builder{}

	b.WriteString("-ldflags=")

	if !*KeepDebugFlags {
		b.WriteString("-s -w")
	}

	if CommitHash != "" {
		b.WriteString(" -X ")
		b.WriteString("git.milar.in/milarin/buildinfo.Commit")
		b.WriteString("=")
		b.WriteString(CommitHash)
	}

	if VersionTag != "" {
		b.WriteString(" -X ")
		b.WriteString("git.milar.in/milarin/buildinfo.Version")
		b.WriteString("=")
		b.WriteString(VersionTag)
	}

	b.WriteString(" -X ")
	b.WriteString("git.milar.in/milarin/buildinfo.Name")
	b.WriteString("=")
	b.WriteString(ProjectName)

	b.WriteString(" -X ")
	b.WriteString("git.milar.in/milarin/buildinfo.BuildTime")
	b.WriteString("=")
	b.WriteString(BuildTime)

	b.WriteString(" -X ")
	b.WriteString("git.milar.in/milarin/buildinfo.OS")
	b.WriteString("=")
	b.WriteString(os)

	b.WriteString(" -X ")
	b.WriteString("git.milar.in/milarin/buildinfo.Arch")
	b.WriteString("=")
	b.WriteString(arch)

	return b.String()
}