package main

import (
	"fmt"
	"os"
	"sort"
	"strings"
	"sync"
	"time"

	alpm "github.com/jguer/go-alpm"
	rpc "github.com/mikkeloscar/aur"
)

type aurWarnings struct {
	Orphans   []string
	OutOfDate []string
	Missing   []string
}

// Query is a collection of Results
type aurQuery []rpc.Pkg

// Query holds the results of a repository search.
type repoQuery []alpm.Package

func (q aurQuery) Len() int {
	return len(q)
}

func (q aurQuery) Less(i, j int) bool {
	var result bool

	switch config.SortBy {
	case "votes":
		result = q[i].NumVotes > q[j].NumVotes
	case "popularity":
		result = q[i].Popularity > q[j].Popularity
	case "name":
		result = lessRunes([]rune(q[i].Name), []rune(q[j].Name))
	case "base":
		result = lessRunes([]rune(q[i].PackageBase), []rune(q[j].PackageBase))
	case "submitted":
		result = q[i].FirstSubmitted < q[j].FirstSubmitted
	case "modified":
		result = q[i].LastModified < q[j].LastModified
	case "id":
		result = q[i].ID < q[j].ID
	case "baseid":
		result = q[i].PackageBaseID < q[j].PackageBaseID
	}

	if config.SortMode == bottomUp {
		return !result
	}

	return result
}

func (q aurQuery) Swap(i, j int) {
	q[i], q[j] = q[j], q[i]
}

// FilterPackages filters packages based on source and type from local repository.
func filterPackages() (local []alpm.Package, remote []alpm.Package,
	localNames []string, remoteNames []string, err error) {
	localDb, err := alpmHandle.LocalDb()
	if err != nil {
		return
	}
	dbList, err := alpmHandle.SyncDbs()
	if err != nil {
		return
	}

	f := func(k alpm.Package) error {
		found := false
		// For each DB search for our secret package.
		_ = dbList.ForEach(func(d alpm.Db) error {
			if found {
				return nil
			}
			_, err := d.PkgByName(k.Name())
			if err == nil {
				found = true
				local = append(local, k)
				localNames = append(localNames, k.Name())
			}
			return nil
		})

		if !found {
			remote = append(remote, k)
			remoteNames = append(remoteNames, k.Name())
		}
		return nil
	}

	err = localDb.PkgCache().ForEach(f)
	return
}

// NarrowSearch searches AUR and narrows based on subarguments
func narrowSearch(pkgS []string, sortS bool) (aurQuery, error) {
	var r []rpc.Pkg
	var err error
	var usedIndex int

	if len(pkgS) == 0 {
		return nil, nil
	}

	for i, word := range pkgS {
		r, err = rpc.Search(word)
		if err == nil {
			usedIndex = i
			break
		}
	}

	if err != nil {
		return nil, err
	}

	if len(pkgS) == 1 {
		if sortS {
			sort.Sort(aurQuery(r))
		}
		return r, err
	}

	var aq aurQuery
	var n int

	for _, res := range r {
		match := true
		for i, pkgN := range pkgS {
			if usedIndex == i {
				continue
			}

			if !(strings.Contains(res.Name, pkgN) || strings.Contains(strings.ToLower(res.Description), pkgN)) {
				match = false
				break
			}
		}

		if match {
			n++
			aq = append(aq, res)
		}
	}

	if sortS {
		sort.Sort(aq)
	}

	return aq, err
}

// SyncSearch presents a query to the local repos and to the AUR.
func syncSearch(pkgS []string) (err error) {
	pkgS = removeInvalidTargets(pkgS)
	var aurErr error
	var repoErr error
	var aq aurQuery
	var pq repoQuery

	if mode == modeAUR || mode == modeAny {
		aq, aurErr = narrowSearch(pkgS, true)
	}
	if mode == modeRepo || mode == modeAny {
		pq, repoErr = queryRepo(pkgS)
		if repoErr != nil {
			return err
		}
	}

	if config.SortMode == bottomUp {
		if mode == modeAUR || mode == modeAny {
			aq.printSearch(1)
		}
		if mode == modeRepo || mode == modeAny {
			pq.printSearch()
		}
	} else {
		if mode == modeRepo || mode == modeAny {
			pq.printSearch()
		}
		if mode == modeAUR || mode == modeAny {
			aq.printSearch(1)
		}
	}

	if aurErr != nil {
		fmt.Fprintf(os.Stderr, "Error during AUR search: %s\n", aurErr)
		fmt.Fprintln(os.Stderr, "Showing Repo packages only")
	}

	return nil
}

// SyncInfo serves as a pacman -Si for repo packages and AUR packages.
func syncInfo(pkgS []string) (err error) {
	var info []*rpc.Pkg
	missing := false
	pkgS = removeInvalidTargets(pkgS)
	aurS, repoS, err := packageSlices(pkgS)
	if err != nil {
		return
	}

	if len(aurS) != 0 {
		noDb := make([]string, 0, len(aurS))

		for _, pkg := range aurS {
			_, name := splitDbFromName(pkg)
			noDb = append(noDb, name)
		}

		info, err = aurInfoPrint(noDb)
		if err != nil {
			missing = true
			fmt.Fprintln(os.Stderr, err)
		}
	}

	// Repo always goes first
	if len(repoS) != 0 {
		arguments := cmdArgs.copy()
		arguments.clearTargets()
		arguments.addTarget(repoS...)
		err = show(passToPacman(arguments))

		if err != nil {
			return
		}
	}

	if len(aurS) != len(info) {
		missing = true
	}

	if len(info) != 0 {
		for _, pkg := range info {
			PrintInfo(pkg)
		}
	}

	if missing {
		err = fmt.Errorf("")
	}

	return
}

// Search handles repo searches. Creates a RepoSearch struct.
func queryRepo(pkgInputN []string) (s repoQuery, err error) {
	dbList, err := alpmHandle.SyncDbs()
	if err != nil {
		return
	}

	dbList.ForEach(func(db alpm.Db) error {
		if len(pkgInputN) == 0 {
			pkgs := db.PkgCache()
			s = append(s, pkgs.Slice()...)
		} else {
			pkgs := db.Search(pkgInputN)
			s = append(s, pkgs.Slice()...)
		}
		return nil
	})

	if config.SortMode == bottomUp {
		for i, j := 0, len(s)-1; i < j; i, j = i+1, j-1 {
			s[i], s[j] = s[j], s[i]
		}
	}

	return
}

// PackageSlices separates an input slice into aur and repo slices
func packageSlices(toCheck []string) (aur []string, repo []string, err error) {
	dbList, err := alpmHandle.SyncDbs()
	if err != nil {
		return
	}

	for _, _pkg := range toCheck {
		db, name := splitDbFromName(_pkg)
		found := false

		if db == "aur" || mode == modeAUR {
			aur = append(aur, _pkg)
			continue
		} else if db != "" || mode == modeRepo {
			repo = append(repo, _pkg)
			continue
		}

		_ = dbList.ForEach(func(db alpm.Db) error {
			_, err := db.PkgByName(name)

			if err == nil {
				found = true
				return fmt.Errorf("")

			}
			return nil
		})

		if !found {
			_, errdb := dbList.PkgCachebyGroup(name)
			found = errdb == nil
		}

		if found {
			repo = append(repo, _pkg)
		} else {
			aur = append(aur, _pkg)
		}
	}

	return
}

// HangingPackages returns a list of packages installed as deps
// and unneeded by the system
// removeOptional decides whether optional dependencies are counted or not
func hangingPackages(removeOptional bool) (hanging []string, err error) {
	localDb, err := alpmHandle.LocalDb()
	if err != nil {
		return
	}

	// safePackages represents every package in the system in one of 3 states
	// State = 0 - Remove package from the system
	// State = 1 - Keep package in the system; need to iterate over dependencies
	// State = 2 - Keep package and have iterated over dependencies
	safePackages := make(map[string]uint8)
	// provides stores a mapping from the provides name back to the original package name
	provides := make(mapStringSet)
	packages := localDb.PkgCache()

	// Mark explicit dependencies and enumerate the provides list
	setupResources := func(pkg alpm.Package) error {
		if pkg.Reason() == alpm.PkgReasonExplicit {
			safePackages[pkg.Name()] = 1
		} else {
			safePackages[pkg.Name()] = 0
		}

		pkg.Provides().ForEach(func(dep alpm.Depend) error {
			provides.Add(dep.Name, pkg.Name())
			return nil
		})
		return nil
	}
	packages.ForEach(setupResources)

	iterateAgain := true
	processDependencies := func(pkg alpm.Package) error {
		if state := safePackages[pkg.Name()]; state == 0 || state == 2 {
			return nil
		}

		safePackages[pkg.Name()] = 2

		// Update state for dependencies
		markDependencies := func(dep alpm.Depend) error {
			// Don't assume a dependency is installed
			state, ok := safePackages[dep.Name]
			if !ok {
				// Check if dep is a provides rather than actual package name
				if pset, ok2 := provides[dep.Name]; ok2 {
					for p := range pset {
						if safePackages[p] == 0 {
							iterateAgain = true
							safePackages[p] = 1
						}
					}
				}

				return nil
			}

			if state == 0 {
				iterateAgain = true
				safePackages[dep.Name] = 1
			}
			return nil
		}

		pkg.Depends().ForEach(markDependencies)
		if !removeOptional {
			pkg.OptionalDepends().ForEach(markDependencies)
		}
		return nil
	}

	for iterateAgain {
		iterateAgain = false
		packages.ForEach(processDependencies)
	}

	// Build list of packages to be removed
	packages.ForEach(func(pkg alpm.Package) error {
		if safePackages[pkg.Name()] == 0 {
			hanging = append(hanging, pkg.Name())
		}
		return nil
	})

	return
}

func lastBuildTime() (time.Time, error) {
	var time time.Time

	pkgs, _, _, _, err := filterPackages()
	if err != nil {
		return time, err
	}

	for _, pkg := range pkgs {
		thisTime := pkg.BuildDate()
		if thisTime.After(time) {
			time = thisTime
		}
	}

	return time, nil
}

// Statistics returns statistics about packages installed in system
func statistics() (info struct {
	Totaln    int
	Expln     int
	TotalSize int64
}, err error) {
	var tS int64 // TotalSize
	var nPkg int
	var ePkg int

	localDb, err := alpmHandle.LocalDb()
	if err != nil {
		return
	}

	for _, pkg := range localDb.PkgCache().Slice() {
		tS += pkg.ISize()
		nPkg++
		if pkg.Reason() == 0 {
			ePkg++
		}
	}

	info = struct {
		Totaln    int
		Expln     int
		TotalSize int64
	}{
		nPkg, ePkg, tS,
	}

	return
}

// Queries the aur for information about specified packages.
// All packages should be queried in a single rpc request except when the number
// of packages exceeds the number set in config.RequestSplitN.
// If the number does exceed config.RequestSplitN multiple rpc requests will be
// performed concurrently.
func aurInfo(names []string, warnings *aurWarnings) ([]*rpc.Pkg, error) {
	info := make([]*rpc.Pkg, 0, len(names))
	seen := make(map[string]int)
	var mux sync.Mutex
	var wg sync.WaitGroup
	var errs MultiError

	makeRequest := func(n, max int) {
		defer wg.Done()
		tempInfo, requestErr := rpc.Info(names[n:max])
		errs.Add(requestErr)
		if requestErr != nil {
			return
		}
		mux.Lock()
		for _, _i := range tempInfo {
			i := _i
			info = append(info, &i)
		}
		mux.Unlock()
	}

	for n := 0; n < len(names); n += config.RequestSplitN {
		max := min(len(names), n+config.RequestSplitN)
		wg.Add(1)
		go makeRequest(n, max)
	}

	wg.Wait()

	if err := errs.Return(); err != nil {
		return info, err
	}

	for k, pkg := range info {
		seen[pkg.Name] = k
	}

	for _, name := range names {
		i, ok := seen[name]
		if !ok {
			warnings.Missing = append(warnings.Missing, name)
			continue
		}

		pkg := info[i]

		if pkg.Maintainer == "" {
			warnings.Orphans = append(warnings.Orphans, name)
		}
		if pkg.OutOfDate != 0 {
			warnings.OutOfDate = append(warnings.OutOfDate, name)
		}
	}

	return info, nil
}

func aurInfoPrint(names []string) ([]*rpc.Pkg, error) {
	fmt.Println(bold(cyan("::") + bold(" Querying AUR...")))

	warnings := &aurWarnings{}
	info, err := aurInfo(names, warnings)
	if err != nil {
		return info, err
	}

	warnings.print()

	return info, nil
}