using ClaudeDo.Data;
using ClaudeDo.Data.Git;
using ClaudeDo.Data.Models;
using ClaudeDo.Data.Repositories;
using ClaudeDo.Worker.Config;
using Microsoft.EntityFrameworkCore;

namespace ClaudeDo.Worker.Runner;

public sealed record WorktreeContext(string WorktreePath, string BranchName, string BaseCommit);

public sealed class WorktreeManager
{
    private readonly GitService _git;
    private readonly IDbContextFactory<ClaudeDoDbContext> _dbFactory;
    private readonly WorkerConfig _cfg;
    private readonly ILogger<WorktreeManager> _logger;

    public WorktreeManager(GitService git, IDbContextFactory<ClaudeDoDbContext> dbFactory, WorkerConfig cfg, ILogger<WorktreeManager> logger)
    {
        _git = git;
        _dbFactory = dbFactory;
        _cfg = cfg;
        _logger = logger;
    }

    public async Task<WorktreeContext> CreateAsync(TaskEntity task, ListEntity list, CancellationToken ct)
    {
        var workingDir = list.WorkingDir
            ?? throw new InvalidOperationException("list.WorkingDir is null");

        if (!await _git.IsGitRepoAsync(workingDir, ct))
            throw new InvalidOperationException($"working_dir is not a git repository: {workingDir}");

        var baseCommit = await _git.RevParseHeadAsync(workingDir, ct);
        // Use the full task id (dashes stripped) in the branch name so
        // two GUIDs sharing an 8-char prefix cannot collide on the same branch.
        var idForBranch = task.Id.Replace("-", "");
        var branchName = $"claudedo/{idForBranch}";
        var slug = CommitMessageBuilder.ToSlug(list.Name);

        var worktreePath = _cfg.WorktreeRootStrategy.Equals("central", StringComparison.OrdinalIgnoreCase)
            ? Path.Combine(_cfg.CentralWorktreeRoot, slug, task.Id)
            : Path.Combine(Path.GetDirectoryName(workingDir)!, ".claudedo-worktrees", slug, task.Id);

        worktreePath = Path.GetFullPath(worktreePath);

        // Ensure parent directory exists.
        Directory.CreateDirectory(Path.GetDirectoryName(worktreePath)!);

        // Create the worktree (this also creates the directory).
        await _git.WorktreeAddAsync(workingDir, branchName, worktreePath, baseCommit, ct);

        // Insert worktrees row AFTER git succeeds — if git throws, no row is created.
        using var context = _dbFactory.CreateDbContext();
        var wtRepo = new WorktreeRepository(context);
        await wtRepo.AddAsync(new WorktreeEntity
        {
            TaskId = task.Id,
            Path = worktreePath,
            BranchName = branchName,
            BaseCommit = baseCommit,
            HeadCommit = null,
            DiffStat = null,
            State = WorktreeState.Active,
            CreatedAt = DateTime.UtcNow,
        }, ct);

        _logger.LogInformation("Created worktree for task {TaskId} at {Path} (branch {Branch}, base {Base})",
            task.Id, worktreePath, branchName, baseCommit);

        return new WorktreeContext(worktreePath, branchName, baseCommit);
    }

    /// <returns>true if a commit was made; false if no changes.</returns>
    public async Task<bool> CommitIfChangedAsync(WorktreeContext ctx, TaskEntity task, ListEntity list, CancellationToken ct)
    {
        if (!await _git.HasChangesAsync(ctx.WorktreePath, ct))
        {
            _logger.LogInformation("No changes in worktree for task {TaskId}, skipping commit", task.Id);
            return false;
        }

        await _git.AddAllAsync(ctx.WorktreePath, ct);

        var message = CommitMessageBuilder.Build(
            task.CommitType, list.Name, task.Title, task.Description, task.Id);

        await _git.CommitAsync(ctx.WorktreePath, message, ct);

        var head = await _git.RevParseHeadAsync(ctx.WorktreePath, ct);
        var diffStat = await _git.DiffStatAsync(ctx.WorktreePath, ctx.BaseCommit, head, ct);

        using var context = _dbFactory.CreateDbContext();
        var wtRepo = new WorktreeRepository(context);
        await wtRepo.UpdateHeadAsync(task.Id, head, diffStat, ct);

        _logger.LogInformation("Committed changes for task {TaskId}: {Head}", task.Id, head);
        return true;
    }
}