using System.Text.Json;
using System.Text.Json.Nodes;
using SoroushAsadi.Data;

namespace SoroushAsadi.Services;

/// <summary>
/// Merges hardcoded default content with admin overrides stored in SQLite.
/// Sections are keyed by name ("hero", "services", etc.).
/// The stored JSON is {"fa": {...}, "en": {...}} for bilingual sections,
/// or a slug-keyed map for "posts".
/// </summary>
public class ContentService(AppDbContext db)
{
    private static readonly JsonSerializerOptions _json =
        new() { PropertyNameCaseInsensitive = true };

    // ── Public API ────────────────────────────────────────────────────────

    /// <summary>Returns the merged content for a section as a JsonNode.
    /// Callers get the locale-specific sub-object (e.g. node["en"]).</summary>
    public JsonNode? GetSection(string key)
    {
        try
        {
            var row = db.ContentSections.Find(key);
            if (row is null) return null;
            return JsonNode.Parse(row.DataJson);
        }
        catch { return null; }
    }

    /// <summary>Returns merged bilingual content for the given section + locale.</summary>
    public JsonNode? GetSectionLocale(string key, string locale)
    {
        var node = GetSection(key);
        return node?[locale];
    }

    /// <summary>Returns all section rows (for admin listing).</summary>
    public IReadOnlyList<string> GetSectionKeys() =>
        db.ContentSections.Select(s => s.Key).ToList();

    /// <summary>Upserts a section's JSON data.</summary>
    public void SaveSection(string key, string json)
    {
        var row = db.ContentSections.Find(key);
        if (row is null)
        {
            row = new Models.ContentSection { Key = key };
            db.ContentSections.Add(row);
        }
        row.DataJson = json;
        row.UpdatedAt = DateTimeOffset.UtcNow.ToUnixTimeMilliseconds();
        db.SaveChanges();
    }

    /// <summary>Deletes a section override (restores built-in default).</summary>
    public void DeleteSection(string key)
    {
        var row = db.ContentSections.Find(key);
        if (row is not null)
        {
            db.ContentSections.Remove(row);
            db.SaveChanges();
        }
    }

    // ── Posts (stored under key "posts") ─────────────────────────────────

    public const string PostsKey = "posts";

    /// <summary>Returns the slug→PostContent map from DB, or empty.</summary>
    public Dictionary<string, JsonNode> GetPostOverrides()
    {
        try
        {
            var row = db.ContentSections.Find(PostsKey);
            if (row is null) return [];
            var parsed = JsonNode.Parse(row.DataJson);
            if (parsed is not JsonObject obj) return [];
            return obj.ToDictionary(kv => kv.Key, kv => kv.Value!);
        }
        catch { return []; }
    }

    /// <summary>Saves a single post override.</summary>
    public void SavePost(string slug, JsonNode content)
    {
        var row = db.ContentSections.Find(PostsKey);
        JsonObject obj;
        if (row is null)
        {
            obj = [];
            row = new Models.ContentSection { Key = PostsKey };
            db.ContentSections.Add(row);
        }
        else
        {
            obj = JsonNode.Parse(row.DataJson) as JsonObject ?? [];
        }
        obj[slug] = content.DeepClone();
        row.DataJson = obj.ToJsonString();
        row.UpdatedAt = DateTimeOffset.UtcNow.ToUnixTimeMilliseconds();
        db.SaveChanges();
    }
}