package debian

import (
	"bufio"
	"os"
	"strings"

	"go.wit.com/lib/fhelp"
	"go.wit.com/lib/protobuf/zoopb"
	"go.wit.com/log"
)

// obviously a hack at this point
// read the package list file from mirrors.wit.com
func InitWitMirrors(m *zoopb.Machine) error {
	m.Wit = zoopb.NewPackages()
	err := scanPackageListFile(m, "/var/lib/apt/lists/mirrors.wit.com_wit_dists_sid_main_binary-amd64_Packages")
	return err
}

// adds the package if the name isn't there
// if it's newer, remove the old package and use the new one
func AddIfNewer(all *zoopb.Packages, p *zoopb.Package) {
	check := all.FindByPackage(p.Package)
	if check == nil {
		all.Append(p)
		return
	}
	v1, _ := fhelp.NewDebVersion(check.Version)
	v2, _ := fhelp.NewDebVersion(p.Version)
	if v1.Equal(v2) {
		// log.Info("do nothing", v1, v2)
		return
	}
	if v1.LessThan(v2) {
		// log.Info("removing", v1, "using", v2)
		all.Delete(check)
		all.Append(p)
	} else {
		// log.Info("keeping", v1, "got:", v2)
	}
}

func fillPB(p *zoopb.Package, namemap map[string]string) error {
	for varname, s := range namemap {
		s = strings.TrimSpace(s)
		varname = strings.TrimSpace(varname)
		varname := strings.TrimSuffix(varname, ":")
		// some junk that was in some that we made
		if varname == "size" || varname == "servers" || varname == "GoPath" {
			continue
		}
		if varname == "MD5sum" {
			varname = "MD5SUM"
		}
		if varname == "Build-Depends" {
			varname = "BuildDepends"
		}
		if varname == "Package-Build-Date" {
			varname = "PackageBuildDate"
		}
		if varname == "Git-Tag-Date" {
			varname = "GitTagDate"
		}
		if ok, err := SetString(p, varname, s); ok {
			continue
		} else {
			log.Printf("%s: var=%s val=%s err=%v\n", p.Package, varname, s, err)
		}
	}
	// log.Info("")
	return nil
}

// breaks up the apt list file into sections
// then sends each section to be processed
// and added to zoopb.Machine.Wit
func scanPackageListFile(m *zoopb.Machine, filename string) error {
	file, err := os.Open(filename)
	if err != nil {
		return err
	}
	defer file.Close()
	scanner := bufio.NewScanner(file)
	var debInfo string
	for scanner.Scan() {
		line := scanner.Text()
		if line == "" {
			p, namemap := parsePackageInfo(debInfo)
			_ = namemap
			fillPB(p, namemap)
			AddIfNewer(m.Wit, p)
			debInfo = ""
		}
		debInfo += line + "\n"
	}
	p, _ := parsePackageInfo(debInfo)
	m.Wit.Append(p)
	return nil
}

/*
func (m *Machine) addPackage(name string, version string, filename string) {
	if name == "" {
		return
	}
	// log.Info("addPackage:", name, version, filename)
	var deb *DebPackage
	var ok bool
	deb, ok = allp[name]
	if !ok {
		deb = NewPackage()
		deb.name.SetLabel(name)
		allp[name] = deb
	}
	newversion := new(Version)
	newversion.v = version
	newversion.file = filename
	deb.versions = append(deb.versions, newversion)
}
*/

// parses dpkg -s foo.deb
func parsePackageInfo(lines string) (*zoopb.Package, map[string]string) {
	var name string
	var version string
	var filename string
	var gopath string
	var last string
	namemap := make(map[string]string)

	for _, line := range strings.Split(lines, "\n") {
		if line == "" {
			continue
		}
		if strings.HasPrefix(line, " ") {
			namemap[last] += line + "\n"
			// these are usually Description: lines
			continue
		}
		if strings.HasPrefix(line, "#") {
			// skip comment lines. (probably doesn't happen in debian list files
			continue
		}
		line = strings.TrimSpace(line)
		parts := strings.Split(line, " ")
		if len(parts) == 1 {
			namemap[parts[0]] = ""
		}
		if len(parts) < 2 {
			continue
		}
		last = parts[0]
		namemap[last] = strings.Join(parts[1:], " ") + "\n"
		if last == "Package:" {
			name = parts[1]
		}
		if last == "Version:" {
			version = parts[1]
		}
		if last == "Filename:" {
			filename = strings.Join(parts[1:], " ")
		}
		if last == "GoPath:" {
			gopath = parts[1]
		}
	}

	p := zoopb.Package{
		Package:   name,
		Version:   version,
		Filename:  filename,
		Namespace: gopath,
	}

	return &p, namemap
}