package forgepb

import (
	"bytes"
	"errors"
	"fmt"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"time"

	"github.com/google/uuid"
	"go.wit.com/lib/hostname"
	"go.wit.com/lib/protobuf/gitpb"
	"go.wit.com/lib/protobuf/httppb"
	"go.wit.com/log"
	timestamppb "google.golang.org/protobuf/types/known/timestamppb"
)

func (p *Patches) HttpPostVerbose(baseURL string, route string) (*Patches, *httppb.HttpRequest, error) {
	p.PrintTable()
	return p.HttpPost(baseURL, route)
}

func (p *Set) HttpPostVerbose(baseURL string, route string) (*Set, *httppb.HttpRequest, error) {
	p.PrintTable()
	return p.HttpPost(baseURL, route)
}

func (p *Sets) HttpPostVerbose(baseURL string, route string) (*Sets, *httppb.HttpRequest, error) {
	p.PrintTable()
	return p.HttpPost(baseURL, route)
}

func newPatchset(name string) *Set {
	pset := new(Set)
	pset.Name = name
	pset.Ctime = timestamppb.New(time.Now())
	pset.Uuid = uuid.New().String()
	pset.Hostname, _ = hostname.Get()
	pset.Patches = NewPatches()

	return pset
}

// creates a patchset
// works from the user branches against the devel branches
func (f *Forge) MakeDevelPatchSet(name string) (*Set, error) {
	pset := newPatchset(name)
	if os.Getenv("GIT_AUTHOR_NAME") == "" {
		return nil, fmt.Errorf("GIT_AUTHOR_NAME not set")
	} else {
		pset.GitAuthorName = os.Getenv("GIT_AUTHOR_NAME")
	}
	if os.Getenv("GIT_AUTHOR_EMAIL") == "" {
		return nil, fmt.Errorf("GIT_AUTHOR_EMAIL not set")
	} else {
		pset.GitAuthorEmail = os.Getenv("GIT_AUTHOR_EMAIL")
	}

	dir, err := os.MkdirTemp("", "forge")
	if err != nil {
		return nil, err
	}
	// defer os.RemoveAll(dir) // clean up
	pset.TmpDir = dir

	all := f.Repos.SortByFullPath()
	for all.Scan() {
		repo := all.Next()

		if !repo.IsLocalBranch(repo.GetUserBranchName()) {
			// log.Info("repo doesn't have user branch", repo.GetGoPath())
			continue
		}
		if !repo.IsLocalBranch(repo.GetDevelBranchName()) {
			// log.Info("repo doesn't have devel branch", repo.GetGoPath())
			continue
		}

		if repo.ActualGetDevelHash() == repo.ActualGetUserHash() {
			continue
		}

		// make a patchset from user to devel
		// TODO: verify branches are otherwise exact
		pset.StartBranchName = repo.GetDevelBranchName()
		pset.EndBranchName = repo.GetUserBranchName()

		err := pset.makePatchSetNew(repo)
		if err != nil {
			return nil, err
		}
	}
	return pset, nil
}

func (pset *Set) makePatchSetNew(repo *gitpb.Repo) error {
	startBranch := pset.StartBranchName
	endBranch := pset.EndBranchName
	repoDir := filepath.Join(pset.TmpDir, repo.GetGoPath())
	err := os.MkdirAll(repoDir, 0755)
	if err != nil {
		return err
	}

	// maybe better? maybe worse?
	// git format-patch -o patches --stdout <commit-range> > my-patch.mbox
	// git format-patch --stdout -5 > my-patch.mbox  # last 5 patches
	// git am < my-patch.mbox
	// git format-patch branch1..branch2
	// export GIT_COMMITTER_DATE="2024-01-01T12:00:00"
	// export GIT_AUTHOR_DATE="2024-01-01T12:00:00"
	// export GIT_COMMITTER_NAME="Your Name"
	// export GIT_COMMITTER_EMAIL="your.email@example.com"
	// export GIT_AUTHOR_NAME="Your Name"
	// export GIT_AUTHOR_EMAIL="your.email@example.com"
	// git am < patch.mbox

	cmd := []string{"git", "format-patch", "-o", repoDir, startBranch + ".." + endBranch}
	r := repo.Run(cmd)
	if r.Error != nil {
		log.Info("git format-patch", repo.FullPath)
		log.Info("git format-patch", cmd)
		log.Info("git format-patch error", r.Error)
		return r.Error
	}
	if r.Exit != 0 {
		log.Info("git format-patch", repo.FullPath)
		log.Info("git format-patch", cmd)
		log.Info("git format-patch exit", r.Exit)
		return errors.New(fmt.Sprintf("git returned %d", r.Exit))
	}
	if len(r.Stdout) == 0 {
		log.Infof("No patches in %s (%s,%s)\n", repo.FullPath, repo.ActualGetDevelHash(), repo.ActualGetUserHash())
		// git created no files to add
		return nil
	}

	err = pset.addPatchFiles(repo, repoDir)
	log.Infof("Added %d patches for %s len=%d\n", len(r.Stdout), repo.FullPath, pset.Patches.Len())
	// pset.PrintTable()
	return err
}

// git show <original_commit_hash> | git patch-id
// git cat-file -p <commit_hash> | grep tree
// process each file in pDir/
func (p *Set) addPatchFiles(repo *gitpb.Repo, fullDir string) error {
	var baderr error
	// log.Info("ADD PATCH FILES ADDED DIR", fullDir)
	filepath.Walk(fullDir, func(path string, info os.FileInfo, err error) error {
		if err != nil {
			// Handle possible errors, like permission issues
			fmt.Fprintf(os.Stderr, "error accessing path %q: %v\n", path, err)
			baderr = err
			return err
		}

		if info.IsDir() {
			return nil
		}
		data, err := os.ReadFile(path)
		if err != nil {
			log.Info("addPatchFile() failed", path)
			baderr = err
			return err
		}
		patch := new(Patch)
		patch.Filename, _ = filepath.Rel(p.TmpDir, path)
		patch.Data = data
		if err := patch.parseData(); err != nil {
			log.Info("parseData() failed", err)
			return err
		}
		if err := findPatchId(repo, patch); err != nil {
			log.Info("findPatchId() failed", err)
			return err
		}
		patch.StartHash = repo.ActualDevelHash()
		patch.NewHash = "na"
		patch.Namespace = repo.GetGoPath()
		if p.Patches == nil {
			log.Info("SHOULD NOT HAVE HAPPENED. p.Patches == nil")
			p.Patches = new(Patches)
		}
		p.Patches.Append(patch)
		// log.Info("ADDED PATCH FILE", path)
		return nil
	})
	return baderr
}

// looks at the git format-patch output
// saves the commit Hash
// saves the diff lines
func (p *Patch) parseData() error {
	lines := strings.Split(string(p.Data), "\n")
	for _, line := range lines {
		fields := strings.Fields(line)
		if len(fields) < 2 {
			continue
		}
		switch fields[0] {
		case "From":
			p.CommitHash = fields[1]
		case "Subject:":
			p.Comment = line
		case "diff":
			p.Files = append(p.Files, line)
		}
	}
	return nil
}

// just an example of how to walk only directories
func onlyWalkDirs(pDir string) error {
	log.Info("DIR", pDir)
	// var all []string
	var baderr error
	filepath.WalkDir(pDir, func(path string, d os.DirEntry, err error) error {
		if err != nil {
			// Handle possible errors, like permission issues
			fmt.Fprintf(os.Stderr, "error accessing path %q: %v\n", path, err)
			baderr = err
			return err
		}

		log.Info("TESTING DIR", path)
		if d.IsDir() {
			return filepath.SkipDir
		}
		log.Info("NEVER GETS HERE? WHAT IS THIS?", path)
		return nil
	})
	return baderr
}

// func runPipe() error {
func findPatchId(repo *gitpb.Repo, p *Patch) error {
	if p.CommitHash == "" {
		return log.Errorf("%s commit hash not found", p.Filename)
	}

	// 1. Create the command to get the diff for the commit.
	//    "git show" is the perfect tool for this.
	cmdShow := exec.Command("git", "show", p.CommitHash)
	cmdShow.Dir = repo.GetFullPath()

	// 2. Create the command to calculate the patch-id from stdin.
	cmdPipeID := exec.Command("git", "patch-id", "--stable")
	cmdPipeID.Dir = repo.GetFullPath()

	// 3. Connect the output of "git show" to the input of "git patch-id".
	//    This is the Go equivalent of the shell pipe `|`.
	pipe, err := cmdShow.StdoutPipe()
	if err != nil {
		return fmt.Errorf("failed to create pipe: %w", err)
	}
	cmdPipeID.Stdin = pipe

	// 4. We need a buffer to capture the final output from git patch-id.
	var output bytes.Buffer
	cmdPipeID.Stdout = &output

	// 5. Start the reading command (patch-id) first.
	if err := cmdPipeID.Start(); err != nil {
		return fmt.Errorf("failed to start git-patch-id: %w", err)
	}

	// 6. Run the writing command (show). This will block until it's done.
	if err := cmdShow.Run(); err != nil {
		return fmt.Errorf("failed to run git-show: %w", err)
	}

	// 7. Wait for the reading command to finish.
	if err := cmdPipeID.Wait(); err != nil {
		return fmt.Errorf("failed to wait for git-patch-id: %w", err)
	}

	fields := strings.Fields(output.String())
	if len(fields) != 2 {
		return fmt.Errorf("git-patch-id produced empty output")
	}

	if fields[1] != p.CommitHash {
		return fmt.Errorf("patchid did not match %s != %v", p.CommitHash, fields)
	}

	p.PatchId = fields[1]
	return nil
}