using FlatRender.ContentSvc.Domain.Entities;
using FlatRender.ContentSvc.Infrastructure.Data;
using FlatRender.ContentSvc.Models;
using Microsoft.EntityFrameworkCore;

namespace FlatRender.ContentSvc.Application.Services;

/// <summary>
/// CRUD for admin-authored preset stories (premade example videos) per template.
/// Public callers see published stories only; admins see drafts too.
/// </summary>
public class PresetStoryService(ContentDbContext db)
{
    public async Task<List<PresetStorySummary>> GetByProjectAsync(Guid projectId, bool publishedOnly) =>
        await db.PresetStories
            .Where(s => s.ProjectId == projectId && (!publishedOnly || s.IsPublished))
            .OrderBy(s => s.Sort).ThenByDescending(s => s.CreatedAt)
            .Select(s => new PresetStorySummary(
                s.Id, s.ProjectId, s.Name, s.Description, s.Demo, s.MusicId,
                s.Sort, s.IsPublished, s.Scenes.Count, s.CreatedAt, s.UpdatedAt))
            .ToListAsync();

    public async Task<PresetStoryResponse?> GetAsync(Guid id, bool publishedOnly)
    {
        var s = await db.PresetStories
            .Include(x => x.Scenes).ThenInclude(ps => ps.Scene)
            .FirstOrDefaultAsync(x => x.Id == id);
        if (s == null || (publishedOnly && !s.IsPublished)) return null;
        return ToResponse(s);
    }

    public async Task<PresetStoryResponse> CreateAsync(SavePresetStoryRequest req)
    {
        var story = new PresetStory
        {
            ProjectId = req.ProjectId,
            Name = req.Name,
            Description = req.Description,
            Demo = req.Demo,
            MusicId = req.MusicId,
            ScenesSpa = req.ScenesSpa,
            Sort = req.Sort,
            IsPublished = req.IsPublished,
            Scenes = MapScenes(req.Scenes),
        };
        db.PresetStories.Add(story);
        await db.SaveChangesAsync();
        return await ReloadAsync(story.Id);
    }

    public async Task<PresetStoryResponse> UpdateAsync(Guid id, SavePresetStoryRequest req)
    {
        var story = await db.PresetStories.Include(s => s.Scenes).FirstOrDefaultAsync(s => s.Id == id)
            ?? throw new KeyNotFoundException($"Preset story {id} not found");
        story.Name = req.Name;
        story.Description = req.Description;
        story.Demo = req.Demo;
        story.MusicId = req.MusicId;
        if (req.ScenesSpa != null) story.ScenesSpa = req.ScenesSpa;
        story.Sort = req.Sort;
        story.IsPublished = req.IsPublished;
        story.UpdatedAt = DateTime.UtcNow;
        // Replace the scene set wholesale (small, ordered list).
        if (req.Scenes != null)
        {
            db.PresetScenes.RemoveRange(story.Scenes);
            story.Scenes = MapScenes(req.Scenes);
        }
        await db.SaveChangesAsync();
        return await ReloadAsync(story.Id);
    }

    public async Task DeleteAsync(Guid id)
    {
        var story = await db.PresetStories.FirstOrDefaultAsync(s => s.Id == id)
            ?? throw new KeyNotFoundException($"Preset story {id} not found");
        story.DeletedAt = DateTime.UtcNow; // soft delete (global query filter hides it)
        await db.SaveChangesAsync();
    }

    // ── helpers ───────────────────────────────────────────────────────────────
    private static List<PresetScene> MapScenes(List<PresetSceneInput>? scenes) =>
        (scenes ?? []).Select(s => new PresetScene
        {
            SceneId = s.SceneId,
            Sort = s.Sort,
            DefaultDurationSec = s.DefaultDurationSec,
        }).ToList();

    private async Task<PresetStoryResponse> ReloadAsync(Guid id) =>
        ToResponse(await db.PresetStories.Include(x => x.Scenes).ThenInclude(ps => ps.Scene)
            .FirstAsync(x => x.Id == id));

    private static PresetStoryResponse ToResponse(PresetStory s) => new(
        s.Id, s.ProjectId, s.Name, s.Description, s.Demo, s.MusicId, s.ScenesSpa,
        s.Sort, s.IsPublished, s.CreatedAt, s.UpdatedAt,
        s.Scenes.OrderBy(ps => ps.Sort).Select(ps => new PresetSceneResponse(
            ps.Id, ps.SceneId, ps.Scene?.Key, ps.Scene?.Title, ps.Sort, ps.DefaultDurationSec)).ToList());
}