package commands

import (
	"fmt"
	"os"
	"strings"

	"git.dws.rip/DWS/onyx/internal/core"
	"git.dws.rip/DWS/onyx/internal/git"
	gogit "github.com/go-git/go-git/v5"
	"github.com/spf13/cobra"
)

const (
	// OnyxWorkspaceRef is the ref where ephemeral commits are stored
	OnyxWorkspaceRef = "refs/onyx/workspaces/current"

	// MaxCommitTitleLength is the maximum length for a commit title
	MaxCommitTitleLength = 72
)

// NewSaveCmd creates the save command
func NewSaveCmd() *cobra.Command {
	var message string

	cmd := &cobra.Command{
		Use:   "save",
		Short: "Save the current work as a permanent commit",
		Long: `Converts the current ephemeral snapshot into a permanent commit
in the active workstream. This is similar to 'git commit' but works
with Onyx's workstream model.`,
		RunE: func(cmd *cobra.Command, args []string) error {
			return runSave(message)
		},
	}

	cmd.Flags().StringVarP(&message, "message", "m", "", "Commit message (required)")
	cmd.MarkFlagRequired("message")

	return cmd
}

// runSave executes the save command
func runSave(message string) error {
	// Validate the commit message
	if err := validateCommitMessage(message); err != nil {
		return err
	}

	// Get current directory
	cwd, err := os.Getwd()
	if err != nil {
		return fmt.Errorf("failed to get current directory: %w", err)
	}

	// Check if this is an Onyx repository
	if !core.IsOnyxRepo(cwd) {
		return fmt.Errorf("not an Onyx repository")
	}

	// Open the repository
	repo, err := core.Open(cwd)
	if err != nil {
		return fmt.Errorf("failed to open repository: %w", err)
	}
	defer repo.Close()

	// Use ExecuteWithTransaction to capture state_before and state_after
	err = core.ExecuteWithTransaction(repo, "save", message, func() error {
		return executeSave(repo, message)
	})

	if err != nil {
		return err
	}

	fmt.Printf("Successfully saved commit: %s\n", message)
	return nil
}

// executeSave performs the actual save operation
func executeSave(repo *core.OnyxRepository, message string) error {
	gitBackend := git.NewGitBackend(repo.GetGitRepo())
	gitRepo := repo.GetGitRepo()

	// 1. Try to read current ephemeral commit from workspace ref
	ephemeralCommitSHA, err := getEphemeralCommit(gitBackend)

	var treeHash string
	if err != nil {
		// No ephemeral commit yet - this is the first commit or daemon isn't running
		// Use worktree to stage and get tree from working directory
		worktree, err := gitRepo.Worktree()
		if err != nil {
			return fmt.Errorf("failed to get worktree: %w", err)
		}

		// Get all files including untracked ones
		status, err := worktree.Status()
		if err != nil {
			return fmt.Errorf("failed to get status: %w", err)
		}

		// Add all files (including untracked) to the index
		for file := range status {
			_, err = worktree.Add(file)
			if err != nil {
				return fmt.Errorf("failed to add file %s: %w", file, err)
			}
		}

		if len(status) == 0 {
			return fmt.Errorf("no changes to commit")
		}

		// Create a temporary commit to get the tree hash
		// This is a workaround since we need the tree object
		tempCommitHash, err := worktree.Commit("temp for tree extraction", &gogit.CommitOptions{
			All:               true,
			AllowEmptyCommits: false,
		})
		if err != nil {
			return fmt.Errorf("failed to create temporary commit: %w", err)
		}

		// Get the tree hash from the temporary commit
		tempCommit, err := gitRepo.CommitObject(tempCommitHash)
		if err != nil {
			return fmt.Errorf("failed to get temporary commit: %w", err)
		}

		treeHash = tempCommit.TreeHash.String()

		// Note: We leave the temp commit in place - it will be orphaned
		// when we create the real commit, and can be cleaned up by git gc
	} else {
		// 2. Get the commit object to extract the tree
		ephemeralCommit, err := gitBackend.GetCommit(ephemeralCommitSHA)
		if err != nil {
			return fmt.Errorf("failed to get ephemeral commit object: %w", err)
		}
		treeHash = ephemeralCommit.TreeHash.String()
	}

	// 3. Create workstream manager
	wsManager := core.NewWorkstreamManager(repo)

	// 4. Get the current workstream
	currentWorkstream, err := wsManager.GetCurrentWorkstream()
	if err != nil {
		return fmt.Errorf("no active workstream. Use 'onx new' to create one: %w", err)
	}

	// 5. Determine the parent commit
	var parentSHA string
	if !currentWorkstream.IsEmpty() {
		latestCommit, err := currentWorkstream.GetLatestCommit()
		if err != nil {
			return err
		}
		parentSHA = latestCommit.SHA
	} else {
		// For the first commit in the workstream, use the base commit
		baseCommitSHA := currentWorkstream.Metadata["base_commit"]
		if baseCommitSHA == "" {
			// Fallback to getting the base branch HEAD
			baseBranch := currentWorkstream.BaseBranch
			if baseBranch == "" {
				baseBranch = "main"
			}
			branchRef := fmt.Sprintf("refs/heads/%s", baseBranch)
			sha, err := gitBackend.GetRef(branchRef)
			if err == nil {
				parentSHA = sha
			}
		} else {
			parentSHA = baseCommitSHA
		}
	}

	// 6. Create new commit with the user's message
	commitSHA, err := gitBackend.CreateCommit(treeHash, parentSHA, message, "User")
	if err != nil {
		return fmt.Errorf("failed to create commit: %w", err)
	}

	// 7. Add commit to workstream using the manager
	if err := wsManager.AddCommitToWorkstream(commitSHA, message); err != nil {
		return fmt.Errorf("failed to add commit to workstream: %w", err)
	}

	return nil
}

// getEphemeralCommit retrieves the current ephemeral commit SHA
func getEphemeralCommit(gitBackend *git.GitBackend) (string, error) {
	sha, err := gitBackend.GetRef(OnyxWorkspaceRef)
	if err != nil {
		return "", fmt.Errorf("no ephemeral commit found. The daemon may not be running")
	}
	return sha, nil
}

// validateCommitMessage validates the commit message
func validateCommitMessage(message string) error {
	// Check if message is empty
	if strings.TrimSpace(message) == "" {
		return fmt.Errorf("commit message cannot be empty")
	}

	// Split into lines
	lines := strings.Split(message, "\n")

	// Validate title (first line)
	title := strings.TrimSpace(lines[0])
	if title == "" {
		return fmt.Errorf("commit message title cannot be empty")
	}

	if len(title) > MaxCommitTitleLength {
		return fmt.Errorf("commit message title is too long (%d characters). Maximum is %d characters", len(title), MaxCommitTitleLength)
	}

	return nil
}