using SurrealDb.Net;
using TarninaHub.Application.Abstractions;
using TarninaHub.Application.Dtos;

namespace TarninaHub.Infrastructure.Persistence;

public sealed class InnovationService : IInnovationService
{
    private const string SelectFields =
        "type::string(id) AS id, title, summary, description, type::string(challenge) AS challenge, " +
        "stage, cost, contact, media, published, updated_at";

    private readonly ISurrealDbClient _client;

    public InnovationService(ISurrealDbClient client)
    {
        _client = client;
    }

    public async Task<IReadOnlyList<InnovationResponse>> ListAsync(
        string? challengeId,
        string? stage,
        string? query,
        bool onlyPublished,
        CancellationToken cancellationToken)
    {
        var where = BuildFilter(challengeId, stage, query, onlyPublished, out var parameters);

        var response = await _client.RawQuery(
            $"SELECT {SelectFields} FROM innovation{where} ORDER BY updated_at DESC;",
            parameters,
            cancellationToken);
        response.EnsureAllOks();

        var rows = response.GetValue<List<InnovationRow>>(0) ?? [];

        return rows.Select(Map).ToList();
    }

    public async Task<InnovationResponse?> GetAsync(string innovationId, CancellationToken cancellationToken)
    {
        var (table, id) = SurrealRecordId.Split(innovationId);

        var response = await _client.RawQuery(
            $"SELECT {SelectFields} FROM type::record($table, $id) LIMIT 1;",
            new Dictionary<string, object?> { ["table"] = table, ["id"] = id },
            cancellationToken);
        response.EnsureAllOks();

        var rows = response.GetValue<List<InnovationRow>>(0) ?? [];

        return rows.Count > 0 ? Map(rows[0]) : null;
    }

    public async Task<InnovationResponse> CreateAsync(
        InnovationRequest request,
        CancellationToken cancellationToken)
    {
        var id = Guid.NewGuid().ToString("N");
        var (challengeTable, challengeId) = SurrealRecordId.Split(request.ChallengeId);

        var parameters = new Dictionary<string, object?>
        {
            ["id"] = id,
            ["title"] = request.Title,
            ["summary"] = request.Summary ?? string.Empty,
            ["description"] = request.Description ?? string.Empty,
            ["challengeTable"] = challengeTable,
            ["challengeId"] = challengeId,
            ["stage"] = request.Stage,
            ["media"] = request.Media ?? [],
            ["published"] = request.Published,
        };

        var assignments = new List<string>
        {
            "title = $title", "summary = $summary", "description = $description",
            "challenge = type::record($challengeTable, $challengeId)", "stage = $stage",
            "media = $media", "published = $published", "updated_at = time::now()",
        };

        AppendOptional(assignments, parameters, "cost", request.Cost);
        AppendOptionalObject(assignments, parameters, "contact", request.Contact);

        var response = await _client.RawQuery(
            "CREATE type::record('innovation', $id) SET " + string.Join(", ", assignments) + "; " +
            $"SELECT {SelectFields} FROM type::record('innovation', $id) LIMIT 1;",
            parameters,
            cancellationToken);
        response.EnsureAllOks();

        var rows = response.GetValue<List<InnovationRow>>(1) ?? [];

        return Map(rows[0]);
    }

    public async Task<InnovationResponse?> UpdateAsync(
        string innovationId,
        InnovationRequest request,
        CancellationToken cancellationToken)
    {
        var (table, id) = SurrealRecordId.Split(innovationId);
        var (challengeTable, challengeId) = SurrealRecordId.Split(request.ChallengeId);

        var parameters = new Dictionary<string, object?>
        {
            ["table"] = table,
            ["id"] = id,
            ["title"] = request.Title,
            ["summary"] = request.Summary ?? string.Empty,
            ["description"] = request.Description ?? string.Empty,
            ["challengeTable"] = challengeTable,
            ["challengeId"] = challengeId,
            ["stage"] = request.Stage,
            ["media"] = request.Media ?? [],
            ["published"] = request.Published,
        };

        var assignments = new List<string>
        {
            "title = $title", "summary = $summary", "description = $description",
            "challenge = type::record($challengeTable, $challengeId)", "stage = $stage",
            "media = $media", "published = $published", "updated_at = time::now()",
        };

        AppendOptional(assignments, parameters, "cost", request.Cost, clearWhenMissing: true);
        AppendOptionalObject(assignments, parameters, "contact", request.Contact, clearWhenMissing: true);

        var response = await _client.RawQuery(
            $"UPDATE type::record($table, $id) SET {string.Join(", ", assignments)}; " +
            $"SELECT {SelectFields} FROM type::record($table, $id) LIMIT 1;",
            parameters,
            cancellationToken);
        response.EnsureAllOks();

        var rows = response.GetValue<List<InnovationRow>>(1) ?? [];

        return rows.Count > 0 ? Map(rows[0]) : null;
    }

    private static string BuildFilter(
        string? challengeId,
        string? stage,
        string? query,
        bool onlyPublished,
        out Dictionary<string, object?> parameters)
    {
        parameters = new Dictionary<string, object?>();
        var clauses = new List<string>();

        if (!string.IsNullOrWhiteSpace(challengeId))
        {
            var (table, id) = SurrealRecordId.Split(challengeId);
            clauses.Add("challenge = type::record($challengeTable, $challengeId)");
            parameters["challengeTable"] = table;
            parameters["challengeId"] = id;
        }

        if (!string.IsNullOrWhiteSpace(stage))
        {
            clauses.Add("stage = $stage");
            parameters["stage"] = stage;
        }

        if (!string.IsNullOrWhiteSpace(query))
        {
            clauses.Add(
                "(string::contains(string::lowercase(title), string::lowercase($query)) " +
                "OR string::contains(string::lowercase(summary), string::lowercase($query)))");
            parameters["query"] = query;
        }

        if (onlyPublished)
        {
            clauses.Add("published = true");
        }

        return clauses.Count > 0 ? " WHERE " + string.Join(" AND ", clauses) : string.Empty;
    }

    private static void AppendOptional(
        List<string> assignments,
        Dictionary<string, object?> parameters,
        string field,
        string? value,
        bool clearWhenMissing = false)
    {
        if (!string.IsNullOrWhiteSpace(value))
        {
            assignments.Add($"{field} = $field_{field}");
            parameters[$"field_{field}"] = value;
        }
        else if (clearWhenMissing)
        {
            assignments.Add($"{field} = NONE");
        }
    }

    private static void AppendOptionalObject(
        List<string> assignments,
        Dictionary<string, object?> parameters,
        string field,
        IReadOnlyDictionary<string, object?>? value,
        bool clearWhenMissing = false)
    {
        if (value is not null)
        {
            assignments.Add($"{field} = $field_{field}");
            parameters[$"field_{field}"] = value;
        }
        else if (clearWhenMissing)
        {
            assignments.Add($"{field} = NONE");
        }
    }

    private static InnovationResponse Map(InnovationRow row) => new(
        row.Id,
        row.Title,
        row.Summary,
        row.Description,
        row.Challenge,
        row.Stage,
        row.Cost,
        row.Contact is null ? null : row.Contact,
        row.Media.Select(item => (IReadOnlyDictionary<string, object?>)item).ToList(),
        row.Published,
        row.UpdatedAt);
}