package repo

import (
	"context"
	"crypto/rand"
	"fmt"
	"math/big"
	"slices"
	"sort"
	"strings"

	"tangled.org/core/appview/db"
	"tangled.org/core/appview/models"
	"tangled.org/core/appview/pages/repoinfo"
	"tangled.org/core/types"

	"github.com/go-git/go-git/v5/plumbing/object"
)

func sortFiles(files []types.NiceTree) {
	sort.Slice(files, func(i, j int) bool {
		iIsFile := files[i].IsFile
		jIsFile := files[j].IsFile
		if iIsFile != jIsFile {
			return !iIsFile
		}
		return files[i].Name < files[j].Name
	})
}

func sortBranches(branches []types.Branch) {
	slices.SortFunc(branches, func(a, b types.Branch) int {
		if a.IsDefault {
			return -1
		}
		if b.IsDefault {
			return 1
		}
		if a.Commit != nil && b.Commit != nil {
			if a.Commit.Committer.When.Before(b.Commit.Committer.When) {
				return 1
			} else {
				return -1
			}
		}
		return strings.Compare(a.Name, b.Name)
	})
}

func uniqueEmails(commits []*object.Commit) []string {
	emails := make(map[string]struct{})
	for _, commit := range commits {
		if commit.Author.Email != "" {
			emails[commit.Author.Email] = struct{}{}
		}
		if commit.Committer.Email != "" {
			emails[commit.Committer.Email] = struct{}{}
		}
	}
	var uniqueEmails []string
	for email := range emails {
		uniqueEmails = append(uniqueEmails, email)
	}
	return uniqueEmails
}

func balanceIndexItems(commitCount, branchCount, tagCount, fileCount int) (commitsTrunc int, branchesTrunc int, tagsTrunc int) {
	if commitCount == 0 && tagCount == 0 && branchCount == 0 {
		return
	}

	// typically 1 item on right side = 2 files in height
	availableSpace := fileCount / 2

	// clamp tagcount
	if tagCount > 0 {
		tagsTrunc = 1
		availableSpace -= 1 // an extra subtracted for headers etc.
	}

	// clamp branchcount
	if branchCount > 0 {
		branchesTrunc = min(max(branchCount, 1), 3)
		availableSpace -= branchesTrunc // an extra subtracted for headers etc.
	}

	// show
	if commitCount > 0 {
		commitsTrunc = max(availableSpace, 3)
	}

	return
}

// emailToDidOrHandle takes an emailToDidMap from db.GetEmailToDid
// and resolves all dids to handles and returns a new map[string]string
func emailToDidOrHandle(r *Repo, emailToDidMap map[string]string) map[string]string {
	if emailToDidMap == nil {
		return nil
	}

	var dids []string
	for _, v := range emailToDidMap {
		dids = append(dids, v)
	}
	resolvedIdents := r.idResolver.ResolveIdents(context.Background(), dids)

	didHandleMap := make(map[string]string)
	for _, identity := range resolvedIdents {
		if !identity.Handle.IsInvalidHandle() {
			didHandleMap[identity.DID.String()] = fmt.Sprintf("@%s", identity.Handle.String())
		} else {
			didHandleMap[identity.DID.String()] = identity.DID.String()
		}
	}

	// Create map of email to didOrHandle for commit display
	emailToDidOrHandle := make(map[string]string)
	for email, did := range emailToDidMap {
		if didOrHandle, ok := didHandleMap[did]; ok {
			emailToDidOrHandle[email] = didOrHandle
		}
	}

	return emailToDidOrHandle
}

func randomString(n int) string {
	const letters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
	result := make([]byte, n)

	for i := 0; i < n; i++ {
		n, _ := rand.Int(rand.Reader, big.NewInt(int64(len(letters))))
		result[i] = letters[n.Int64()]
	}

	return string(result)
}

// grab pipelines from DB and munge that into a hashmap with commit sha as key
//
// golang is so blessed that it requires 35 lines of imperative code for this
func getPipelineStatuses(
	d *db.DB,
	repoInfo repoinfo.RepoInfo,
	shas []string,
) (map[string]models.Pipeline, error) {
	m := make(map[string]models.Pipeline)

	if len(shas) == 0 {
		return m, nil
	}

	ps, err := db.GetPipelineStatuses(
		d,
		db.FilterEq("repo_owner", repoInfo.OwnerDid),
		db.FilterEq("repo_name", repoInfo.Name),
		db.FilterEq("knot", repoInfo.Knot),
		db.FilterIn("sha", shas),
	)
	if err != nil {
		return nil, err
	}

	for _, p := range ps {
		m[p.Sha] = p
	}

	return m, nil
}