package main

import (
	"flag"
	"fmt"
	"os"
	"os/exec"
	"path"
	"strings"

	"git.xdrm.io/go/cliverage/coverage"
)

func main() {
	var codepath string
	var coverfile string
	var filepath string
	var showUsage bool

	flag.StringVar(&codepath, "d", "", "path to where lives your code")
	flag.StringVar(&coverfile, "c", "", "path to the coverage file")
	flag.StringVar(&filepath, "f", ".", "path to the file to print relative to -d option")
	flag.BoolVar(&showUsage, "h", false, "")
	flag.Usage = usage
	flag.Parse()

	// 1. show usage
	if showUsage {
		flag.Usage()
		os.Exit(0)
	}

	// 2. missing required arguments
	if len(codepath) < 1 || len(coverfile) < 1 {
		fmt.Printf("%s missing arguments.\n\n", warning("/!\\"))
		fmt.Printf("run -h to show usage.\n")
		os.Exit(1)
	}

	// 3. check codepath
	if info, err := os.Stat(codepath); true {
		if err != nil && os.IsNotExist(err) {
			fmt.Printf("%s codepath does not exist.\n\n", warning("/!\\"))
			os.Exit(1)
		}

		if !info.IsDir() {
			fmt.Printf("%s codepath is not a directory.\n\n", warning("/!\\"))
			os.Exit(1)
		}

		if err != nil {
			fmt.Printf("%s invalid codepath: %s.\n\n", warning("/!\\"), err)
			os.Exit(1)
		}
	}

	// 4. check coverfile
	if info, err := os.Stat(coverfile); true {

		if err != nil && os.IsNotExist(err) {
			fmt.Printf("%s coverfile does not exist.\n\n", warning("/!\\"))
			os.Exit(1)
		}

		if info.IsDir() {
			fmt.Printf("%s coverfile is not a file.\n\n", warning("/!\\"))
			os.Exit(1)
		}

		if err != nil {
			fmt.Printf("%s invalid coverfile: %s.\n\n", warning("/!\\"), err)
			os.Exit(1)
		}
	}

	// 5. extract package path
	os.Chdir(codepath)
	var getGoPkgPath = exec.Command("go", "list", ".")
	pkgPath, err := getGoPkgPath.Output()
	if err != nil {
		fmt.Printf("%s cannot get go package path: %s.\n\n", warning("/!\\"), err)
		os.Exit(1)
	}

	// 6. parse coverfile
	fdCoverfile, err := os.OpenFile(coverfile, os.O_RDONLY, 0755)
	if err != nil {
		fmt.Printf("%s cannot open coverfile: %s.\n\n", warning("/!\\"), err)
		os.Exit(1)
	}
	defer fdCoverfile.Close()
	parsedCoverage, err := coverage.Parse(fdCoverfile, strings.Trim(string(pkgPath), " \t\r\n"))
	if err != nil {
		fmt.Printf("%s error reading coverfile: %s.\n\n", warning("/!\\"), err)
		os.Exit(1)
	}

	// 7. iterate over files
	coveredFiles := parsedCoverage.GetFile(filepath)
	for fname, coveredChunks := range coveredFiles.Files {
		path := path.Join(codepath, fname)
		fmt.Printf("----- %s -----\n", fname)

		fdFile, err := os.OpenFile(path, os.O_RDONLY, 0755)
		if err != nil {
			fmt.Printf("%s cannot open file '%s': %s.\n\n", warning("/!\\"), path, err)
			continue
		}
		defer fdFile.Close()
		printCoverage(fdFile, os.Stdout, coveredChunks)
		fmt.Printf("\n\n")
	}

	os.Exit(0)
}