package lanesnapshot

import (
	"context"
	"fmt"
	"strings"

	"inbox/internal/app/lanegit"
	"inbox/internal/base/timeutil"
	"inbox/internal/domain/lane"
	"inbox/internal/domain/task"
)

type Service struct {
	runner lanegit.Runner
	clock  timeutil.Clock
}

func NewService(runner lanegit.Runner, clock timeutil.Clock) *Service {
	if runner == nil {
		runner = lanegit.ExecRunner{}
	}
	if clock == nil {
		clock = timeutil.SystemClock{}
	}
	return &Service{runner: runner, clock: clock}
}

func (s *Service) Capture(ctx context.Context, item lane.Record, taskRecord task.Record) (string, error) {
	worktree := strings.TrimSpace(item.WorktreePath)
	if worktree == "" {
		return "", fmt.Errorf("lane %s has empty worktree path", item.ID)
	}

	headBefore, err := s.headCommit(ctx, worktree)
	if err != nil {
		return "", err
	}
	changed, err := s.hasChanges(ctx, worktree)
	if err != nil {
		return "", err
	}
	if !changed {
		return headBefore, nil
	}
	if _, err := lanegit.Run(ctx, s.runner, worktree, nil, "add", "-A"); err != nil {
		return "", err
	}
	staged, err := s.hasStagedChanges(ctx, worktree)
	if err != nil {
		return "", err
	}
	if !staged {
		return headBefore, nil
	}

	msg := fmt.Sprintf("lane(%s): complete task %s - %s", strings.TrimSpace(item.Slug), taskRecord.ID, strings.TrimSpace(taskRecord.Title))
	env := map[string]string{
		"GIT_AUTHOR_NAME":     "Inbox",
		"GIT_AUTHOR_EMAIL":    "inbox@local",
		"GIT_COMMITTER_NAME":  "Inbox",
		"GIT_COMMITTER_EMAIL": "inbox@local",
		"GIT_AUTHOR_DATE":     timeutil.FormatRFC3339(s.clock.Now()),
		"GIT_COMMITTER_DATE":  timeutil.FormatRFC3339(s.clock.Now()),
	}
	if _, err := lanegit.Run(ctx, s.runner, worktree, env, "commit", "-m", msg); err != nil {
		return "", err
	}
	return s.headCommit(ctx, worktree)
}

func (s *Service) headCommit(ctx context.Context, worktree string) (string, error) {
	out, err := lanegit.Run(ctx, s.runner, worktree, nil, "rev-parse", "HEAD")
	if err != nil {
		return "", err
	}
	return strings.TrimSpace(out), nil
}

func (s *Service) hasChanges(ctx context.Context, worktree string) (bool, error) {
	out, err := lanegit.Run(ctx, s.runner, worktree, nil, "status", "--porcelain")
	if err != nil {
		return false, err
	}
	return strings.TrimSpace(out) != "", nil
}

func (s *Service) hasStagedChanges(ctx context.Context, worktree string) (bool, error) {
	_, err := s.runner.Run(ctx, worktree, nil, "git", "diff", "--cached", "--quiet", "--exit-code")
	if err == nil {
		return false, nil
	}
	if lanegit.IsExitCode(err, 1) {
		return true, nil
	}
	return false, fmt.Errorf("git diff --cached --quiet --exit-code: %w", err)
}