using System.Security.Cryptography;
using System.Text;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Routing;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Options;
using TeamUp.Modules.Skills.Domain;
using TeamUp.Modules.Skills.Indexing;
using TeamUp.Modules.Skills.Persistence;
using TeamUp.Modules.Skills.Sync;
using TeamUp.SharedKernel.Access;
using TeamUp.SharedKernel.Auditing;
using TeamUp.SharedKernel.Modularity;

namespace TeamUp.Modules.Skills.Endpoints;

internal static class SkillsEndpoints
{
    public static void Map(IEndpointRouteBuilder endpoints)
    {
        var group = endpoints.MapGroup("/api/skills").WithTags("Skills");

        group.MapGet("/ping", () => TypedResults.Ok(new ModulePing("skills")));
        group.MapGet("/", ListSkills).RequireAuthorization();
        group.MapGet("/marketplace", Marketplace).RequireAuthorization();
        group.MapGet("/{key}", GetSkill).RequireAuthorization();
        group.MapPost("/authored", AuthorSkill).RequireAuthorization();
        group.MapPost("/{key}/fork", ForkSkill).RequireAuthorization();
        group.MapPost("/{key}/publish", PublishSkill).RequireAuthorization();
        group.MapPost("/{key}/unpublish", UnpublishSkill).RequireAuthorization();
        group.MapPost("/install", InstallSkill).RequireAuthorization();
        group.MapPost("/index", IndexSkill).RequireAuthorization();
        group.MapPost("/sync", Sync).RequireAuthorization();
        group.MapPost("/webhook/gitea", Webhook).AllowAnonymous();
    }

    // Re-syncing the shared builtin library is an operator action, not a tenant one.
    private static async Task<IResult> Sync(
        HttpContext http, IOptions<SkillAdminOptions> admin, SkillSyncService sync, CancellationToken ct)
    {
        if (!IsPlatformAdmin(http, admin))
        {
            return Results.Forbid();
        }

        return Results.Ok(new SyncResult(await sync.SyncAsync(ct)));
    }

    // Gitea push webhook → re-sync the source. Re-reads only the trusted Git source (no caller
    // content). Signature verification + changed-file-only sync via the job queue land later.
    private static async Task<IResult> Webhook(SkillSyncService sync, CancellationToken ct) =>
        Results.Ok(new SyncResult(await sync.SyncAsync(ct)));

    /// <summary>
    /// Builtins (null-org, all-tenant-visible) may only be managed by a platform operator holding
    /// the configured admin key. Fails closed when no key is configured.
    /// </summary>
    private static bool IsPlatformAdmin(HttpContext http, IOptions<SkillAdminOptions> admin)
    {
        var configured = admin.Value.AdminKey;
        if (string.IsNullOrEmpty(configured) ||
            !http.Request.Headers.TryGetValue("X-Skills-Admin-Key", out var provided))
        {
            return false;
        }

        return CryptographicOperations.FixedTimeEquals(
            Encoding.UTF8.GetBytes(provided.ToString()), Encoding.UTF8.GetBytes(configured));
    }

    private static async Task<IResult> ListSkills(
        Guid? organizationId, string? role, string? visibility,
        IPermissionService permissions, SkillsDbContext db, CancellationToken ct)
    {
        // The library a company sees = the shared builtin starter skills (null org) + its own.
        IQueryable<Skill> query = db.Skills.Where(s => s.OrganizationId == null);
        if (organizationId is { } orgId)
        {
            if (!permissions.Has(Capability.ViewBoard, ScopeRef.Org(orgId)))
            {
                return Results.Forbid();
            }

            query = db.Skills.Where(s => s.OrganizationId == null || s.OrganizationId == orgId);
        }

        if (!string.IsNullOrWhiteSpace(role))
        {
            query = query.Where(s => s.Roles.Contains(role));
        }

        if (Enum.TryParse<SkillVisibility>(visibility, ignoreCase: true, out var vis))
        {
            query = query.Where(s => s.Visibility == vis);
        }

        // Order so the FIRST row per key is exactly the one the run-time catalog resolves
        // (SkillCatalog.GetByKeysAsync): a Published row beats a Draft, the org's own beats the
        // shared builtin, then the latest version — using the same Ordinal version comparison.
        // The seat picker collapses to the first row per key, so display matches what will run.
        var skills = (await query.ToListAsync(ct))
            .OrderBy(s => s.SkillKey, StringComparer.Ordinal)
            .ThenByDescending(s => s.Status == SkillStatus.Published)
            .ThenByDescending(s => s.OrganizationId == organizationId)
            .ThenByDescending(s => s.Version, StringComparer.Ordinal)
            .ToList();

        return Results.Ok(skills.Select(ToSummary).ToList());
    }

    // Marketplace seam (read-only groundwork): publicly-shared, org-authored skills from any org.
    // Publishing controls and install-into-your-org land in the next step.
    // The marketplace: published skills other orgs have listed publicly. Excludes your own skills
    // and flags any whose key already exists in your library (installed or authored).
    private static async Task<IResult> Marketplace(
        Guid organizationId, IPermissionService permissions, SkillsDbContext db, CancellationToken ct)
    {
        if (!permissions.Has(Capability.ViewBoard, ScopeRef.Org(organizationId)))
        {
            return Results.Forbid();
        }

        var listed = await db.Skills
            .Where(s => s.Origin == SkillOrigin.Authored
                && s.Visibility == SkillVisibility.Public
                && s.Status == SkillStatus.Published
                && s.OrganizationId != null
                && s.OrganizationId != organizationId)
            .OrderBy(s => s.SkillKey)
            .ThenByDescending(s => s.Version)
            .ToListAsync(ct);

        // Flag by (key, version) — matching the install conflict rule — so a newer, not-yet-owned
        // version of a key you already hold still shows as installable.
        var owned = (await db.Skills
            .Where(s => s.OrganizationId == organizationId)
            .Select(s => new { s.SkillKey, s.Version })
            .ToListAsync(ct))
            .Select(s => (s.SkillKey, s.Version))
            .ToHashSet();

        return Results.Ok(listed
            .Select(s => new MarketplaceEntry(ToSummary(s), owned.Contains((s.SkillKey, s.Version))))
            .ToList());
    }

    private static async Task<IResult> PublishSkill(
        string key, PublishSkillRequest request, ICurrentUser user, IPermissionService permissions,
        IAuditLog audit, SkillsDbContext db, TimeProvider clock, CancellationToken ct)
    {
        if (!permissions.Has(Capability.ManageSkills, ScopeRef.Org(request.OrganizationId)))
        {
            return Results.Forbid();
        }

        var skill = await db.Skills.FirstOrDefaultAsync(
            s => s.OrganizationId == request.OrganizationId && s.SkillKey == key && s.Version == request.Version, ct);
        if (skill is null)
        {
            return Results.NotFound();
        }

        // Only golden-tested (published) skills may be listed — the marketplace inherits the eval gate.
        if (skill.Status != SkillStatus.Published)
        {
            return Results.BadRequest("Only a published (golden-tested) skill can be listed on the marketplace.");
        }

        skill.SetVisibility(SkillVisibility.Public, clock.GetUtcNow());
        await db.SaveChangesAsync(ct);
        await audit.WriteAsync(
            new AuditEvent("skill.published", "Skill", skill.Id, user.MemberId, $"{skill.SkillKey}@{skill.Version}"), ct);
        return Results.Ok(ToDetail(skill));
    }

    private static async Task<IResult> UnpublishSkill(
        string key, PublishSkillRequest request, ICurrentUser user, IPermissionService permissions,
        IAuditLog audit, SkillsDbContext db, TimeProvider clock, CancellationToken ct)
    {
        if (!permissions.Has(Capability.ManageSkills, ScopeRef.Org(request.OrganizationId)))
        {
            return Results.Forbid();
        }

        var skill = await db.Skills.FirstOrDefaultAsync(
            s => s.OrganizationId == request.OrganizationId && s.SkillKey == key && s.Version == request.Version, ct);
        if (skill is null)
        {
            return Results.NotFound();
        }

        skill.SetVisibility(SkillVisibility.PrivateToOrg, clock.GetUtcNow());
        await db.SaveChangesAsync(ct);
        await audit.WriteAsync(
            new AuditEvent("skill.unpublished", "Skill", skill.Id, user.MemberId, $"{skill.SkillKey}@{skill.Version}"), ct);
        return Results.Ok(ToDetail(skill));
    }

    // Copy a publicly-listed skill into the caller's org as a private Installed copy.
    private static async Task<IResult> InstallSkill(
        InstallSkillRequest request, ICurrentUser user, IPermissionService permissions,
        IAuditLog audit, SkillsDbContext db, SkillIndexer indexer, CancellationToken ct)
    {
        if (!permissions.Has(Capability.ManageSkills, ScopeRef.Org(request.OrganizationId)))
        {
            return Results.Forbid();
        }

        var source = await db.Skills.FirstOrDefaultAsync(s => s.Id == request.SourceSkillId, ct);
        if (source is null)
        {
            return Results.NotFound();
        }

        if (source.Origin != SkillOrigin.Authored
            || source.Visibility != SkillVisibility.Public
            || source.Status != SkillStatus.Published)
        {
            return Results.BadRequest("That skill is not published to the marketplace.");
        }

        if (source.OrganizationId == request.OrganizationId)
        {
            return Results.BadRequest("That skill already belongs to your organization.");
        }

        if (await db.Skills.AnyAsync(
            s => s.OrganizationId == request.OrganizationId && s.SkillKey == source.SkillKey && s.Version == source.Version, ct))
        {
            return Results.Conflict("This skill version is already in your library.");
        }

        var manifest = ToManifest(source);
        manifest.Visibility = "private"; // an installed copy is private until the installer chooses to publish it
        try
        {
            // insertOnly: the DB unique index is the source of truth, so a race with a concurrent
            // install/author of the same (org, key, version) becomes a clean 409, never a clobber.
            var skill = await indexer.IndexAsync(
                manifest, source.Body, SkillOwnership.Installed(request.OrganizationId, user.MemberId),
                insertOnly: true, cancellationToken: ct);
            await audit.WriteAsync(
                new AuditEvent("skill.installed", "Skill", skill.Id, user.MemberId, $"{skill.SkillKey}@{skill.Version}"), ct);
            return Results.Ok(ToDetail(skill));
        }
        catch (DbUpdateException)
        {
            return Results.Conflict("This skill version is already in your library.");
        }
    }

    private static async Task<IResult> GetSkill(
        string key, Guid? organizationId, IPermissionService permissions, SkillsDbContext db, CancellationToken ct)
    {
        if (organizationId is { } orgId && !permissions.Has(Capability.ViewBoard, ScopeRef.Org(orgId)))
        {
            return Results.Forbid();
        }

        var versions = await db.Skills
            .Where(s => s.SkillKey == key && (s.OrganizationId == null || s.OrganizationId == organizationId))
            .OrderByDescending(s => s.OrganizationId != null) // org's own first, then builtins
            .ThenByDescending(s => s.Version)
            .ToListAsync(ct);

        return versions.Count == 0
            ? Results.NotFound()
            : Results.Ok(versions.Select(ToDetail).ToList());
    }

    private static async Task<IResult> AuthorSkill(
        AuthorSkillRequest request, ICurrentUser user, IPermissionService permissions,
        IAuditLog audit, SkillIndexer indexer, CancellationToken ct)
    {
        if (!permissions.Has(Capability.ManageSkills, ScopeRef.Org(request.OrganizationId)))
        {
            return Results.Forbid();
        }

        if (string.IsNullOrWhiteSpace(request.SkillKey) ||
            string.IsNullOrWhiteSpace(request.Name) ||
            string.IsNullOrWhiteSpace(request.Version) ||
            string.IsNullOrWhiteSpace(request.Body))
        {
            return Results.BadRequest("skillKey, name, version, and body are required.");
        }

        var manifest = ToManifest(request);
        var skill = await indexer.IndexAsync(
            manifest, request.Body.Trim(), SkillOwnership.Authored(request.OrganizationId, user.MemberId), cancellationToken: ct);

        await audit.WriteAsync(
            new AuditEvent("skill.authored", "Skill", skill.Id, user.MemberId, $"{skill.SkillKey}@{skill.Version}"), ct);
        return Results.Ok(ToDetail(skill));
    }

    private static async Task<IResult> ForkSkill(
        string key, ForkSkillRequest request, ICurrentUser user, IPermissionService permissions,
        IAuditLog audit, SkillsDbContext db, SkillIndexer indexer, CancellationToken ct)
    {
        if (!permissions.Has(Capability.ManageSkills, ScopeRef.Org(request.OrganizationId)))
        {
            return Results.Forbid();
        }

        // Fork a builtin (or the org's own) version into an editable, org-owned Authored copy.
        var source = await db.Skills.FirstOrDefaultAsync(
            s => s.SkillKey == key && s.Version == request.Version
                && (s.OrganizationId == null || s.OrganizationId == request.OrganizationId),
            ct);
        if (source is null)
        {
            return Results.NotFound();
        }

        var manifest = ToManifest(source);
        if (!string.IsNullOrWhiteSpace(request.Name))
        {
            manifest.Name = request.Name.Trim();
        }

        var skill = await indexer.IndexAsync(
            manifest, source.Body, SkillOwnership.Authored(request.OrganizationId, user.MemberId), cancellationToken: ct);

        await audit.WriteAsync(
            new AuditEvent("skill.forked", "Skill", skill.Id, user.MemberId, $"{skill.SkillKey}@{skill.Version}"), ct);
        return Results.Ok(ToDetail(skill));
    }

    // Posts raw content as a shared builtin → operator-only (otherwise any tenant could inject a
    // global skill). Tenants author org-owned skills via /authored instead.
    private static async Task<IResult> IndexSkill(
        HttpContext http, IOptions<SkillAdminOptions> admin, IndexRequest request, SkillIndexer indexer, CancellationToken ct)
    {
        if (!IsPlatformAdmin(http, admin))
        {
            return Results.Forbid();
        }

        if (string.IsNullOrWhiteSpace(request.Content))
        {
            return Results.BadRequest("content is required.");
        }

        try
        {
            var skill = await indexer.IndexAsync(
                request.Content, request.SourceRepo, request.SourcePath, request.SourceCommit, ct);
            return Results.Ok(ToDetail(skill));
        }
        catch (FormatException ex)
        {
            return Results.BadRequest(ex.Message);
        }
    }

    private static SkillManifest ToManifest(AuthorSkillRequest request) => new()
    {
        Id = request.SkillKey.Trim(),
        Name = request.Name.Trim(),
        Version = request.Version.Trim(),
        Summary = request.Summary,
        Roles = request.Roles ?? [],
        Inputs = request.Inputs,
        Outputs = request.Outputs,
        Actions = (request.Actions ?? [])
            .Select(a => new ManifestAction { Name = a.Name, Risk = a.Risk, Description = a.Description })
            .ToList(),
        Tools = request.Tools ?? [],
        Context = request.Context ?? [],
        // Authored skills are private by default; listing on the marketplace is an explicit publish step.
        Visibility = string.IsNullOrWhiteSpace(request.Visibility) ? "private" : request.Visibility,
        MinTier = string.IsNullOrWhiteSpace(request.MinTier) ? "free" : request.MinTier,
        GoldenTests = (request.GoldenTests ?? [])
            .Select(g => new GoldenExample { Input = g.Input, Expected = g.Expected })
            .ToList(),
    };

    private static SkillManifest ToManifest(Skill skill) => new()
    {
        Id = skill.SkillKey,
        Name = skill.Name,
        Version = skill.Version,
        Summary = skill.Summary,
        Roles = [.. skill.Roles],
        Inputs = skill.Inputs,
        Outputs = skill.Outputs,
        Actions = skill.Actions
            .Select(a => new ManifestAction { Name = a.Name, Risk = a.Risk.ToString(), Description = a.Description })
            .ToList(),
        Tools = [.. skill.Tools],
        Context = [.. skill.Context],
        Visibility = skill.Visibility.ToString(),
        MinTier = skill.MinTier.ToString(),
        GoldenTests = [.. skill.GoldenTests], // Skill.Index clones these onto the new row.
    };

    private static SkillSummary ToSummary(Skill skill) => new(
        skill.Id,
        skill.SkillKey,
        skill.Name,
        skill.Version,
        skill.Summary,
        skill.Roles,
        skill.Visibility.ToString(),
        skill.MinTier.ToString(),
        skill.Status.ToString(),
        skill.Origin.ToString(),
        skill.OrganizationId,
        skill.GoldenTests.Count,
        skill.Actions.Select(a => new ActionDto(a.Name, a.Risk.ToString(), a.Description)).ToList());

    private static SkillDetail ToDetail(Skill skill) => new(
        ToSummary(skill),
        skill.Inputs,
        skill.Outputs,
        skill.Tools,
        skill.Context,
        skill.GoldenTests.Select(g => new GoldenTestDto(g.Input, g.Expected)).ToList(),
        skill.Body);
}