using System.Text;
using System.Text.Json;
using Distribution.Features.GeneralLedger;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;

namespace Distribution.Features.FinanceReport;

/// <summary>
/// Proxies the General Ledger service's reports (TrialBalance, GeneralLedger, BalanceSheet, ProfitAndLoss, CashFlow,
/// BudgetVsActual, TaxSummary). Query parameters are forwarded as-is; Json is returned as the GL data payload and
/// Pdf/Csv are returned as downloadable files.
/// </summary>
[ApiController]
[Route("api/reports/finance")]
public class FinanceReportController(IGeneralLedgerClient gl) : ControllerBase
{
    /// <summary>Active GL accounts (code + name) for the report filters' account dropdown.</summary>
    [HttpGet("accounts")]
    [Authorize("finance-reports.view")]
    public async Task<IActionResult> Accounts(CancellationToken ct)
    {
        GeneralLedgerResult result;
        try { result = await gl.SendAsync(HttpMethod.Get, "v1/accounts?isActive=true", null, ct); }
        catch (HttpRequestException) { return StatusCode(502, new { error = "The General Ledger service is unreachable." }); }

        if (!result.Success || GlJson.Data(result) is not { } data)
            return StatusCode(502, new { error = GlJson.Message(result) ?? "Could not load GL accounts." });

        var items = GlJson.Get(data, "items");
        var accounts = items is { ValueKind: JsonValueKind.Array }
            ? items.Value.EnumerateArray()
                .Select(a => new { accountCode = GlJson.GetString(a, "accountCode") ?? "", accountName = GlJson.GetString(a, "accountName") ?? "" })
                .OrderBy(a => a.accountCode, StringComparer.Ordinal)
                .ToList()
            : [];
        return Ok(accounts);
    }

    [HttpGet("{reportType}")]
    [Authorize("finance-reports.view")]
    public async Task<IActionResult> Get(string reportType, [FromQuery] string outputFormat = "Json", CancellationToken ct = default)
    {
        var query = new StringBuilder($"v1/reports?reportType={Uri.EscapeDataString(reportType)}&outputFormat={Uri.EscapeDataString(outputFormat)}");
        foreach (var (key, values) in Request.Query)
        {
            if (key is "reportType" or "outputFormat") continue;
            foreach (var v in values)
                query.Append('&').Append(Uri.EscapeDataString(key)).Append('=').Append(Uri.EscapeDataString(v ?? ""));
        }

        GeneralLedgerResult result;
        try { result = await gl.SendAsync(HttpMethod.Get, query.ToString(), null, ct); }
        catch (HttpRequestException) { return StatusCode(502, new { error = "The General Ledger service is unreachable." }); }

        if (!result.Success)
            return StatusCode(result.StatusCode is >= 400 and < 500 ? result.StatusCode : 502,
                new { error = GlJson.Message(result) ?? "The General Ledger service rejected the request." });

        var data = GlJson.Data(result);
        if (data is null) return StatusCode(502, new { error = "The General Ledger service returned no data." });

        if (!outputFormat.Equals("Json", StringComparison.OrdinalIgnoreCase))
        {
            var base64 = GlJson.GetString(data.Value, "contentBase64");
            if (base64 is null) return StatusCode(502, new { error = "The General Ledger service returned no file." });
            return File(Convert.FromBase64String(base64),
                GlJson.GetString(data.Value, "contentType") ?? "application/octet-stream",
                GlJson.GetString(data.Value, "fileName"));
        }

        return Content(data.Value.GetRawText(), "application/json");
    }
}