/**
 * @file main.cc
 * @brief Parses command-line options, validates runtime mode selection,
 * initializes shared infrastructure, and executes the pipeline entry flow.
 */

#include <spdlog/spdlog.h>
#include <spdlog/fmt/fmt.h>

#include <boost/di.hpp>
#include <boost/program_options.hpp>
#include <exception>
#include <memory>
#include <optional>
#include <string>
#include <thread>

#include "biergarten_pipeline_orchestrator.h"
#include "concurrency/bounded_channel.h"
#include "data_generation/llama_generator.h"
#include "data_generation/mock_generator.h"
#include "data_generation/prompt_formatting/gemma4_jinja_prompt_formatter.h"
#include "data_model/models.h"
#include "llama_backend_state.h"
#include "services/database/export_service.h"
#include "services/database/sqlite_export_service.h"
#include "services/datetime/timer.h"
#include "services/enrichment/enrichment_service.h"
#include "services/enrichment/mock_enrichment.h"
#include "services/enrichment/wikipedia_service.h"
#include "services/logging/log_dispatcher.h"
#include "services/logging/log_entry.h"
#include "services/logging/log_producer.h"
#include "services/logging/logger.h"
#include "services/prompting/prompt_directory.h"
#include "web_client/http_web_client.h"

namespace di = boost::di;

static constexpr size_t kLogMaxCount = 512;

int main(const int argc, char** argv) {
  spdlog::set_level(spdlog::level::debug);
  spdlog::set_pattern("│ %Y-%m-%d %H:%M:%S.%e │ %^%-7l%$ │ %v");
  BoundedChannel<LogEntry> log_channel(kLogMaxCount);
  auto log_dispatcher = std::make_unique<LogDispatcher>(log_channel);
  std::thread log_thread([&log_dispatcher] { log_dispatcher->Run(); });

  std::shared_ptr<ILogger> log_producer =
      std::make_shared<LogProducer>(log_channel);

  auto shutdown = [&](const int exit_code) {
    log_channel.Close();
    log_thread.join();
    return exit_code;
  };

  try {
    Timer timer;

#ifndef BIERGARTEN_MOCK_ONLY
    const LlamaBackendState llama_backend_state;
#endif

    log_producer->Log(LogLevel::Info, PipelinePhase::Startup, "STARTING PIPELINE");

    const std::optional<ApplicationOptions> parsed_options =
        ParseArguments(argc, argv, log_producer);

    if (!parsed_options.has_value()) {
      return shutdown(0);
    }

    const auto options = *parsed_options;
    const std::string model_path = options.generator.model_path.string();
    const auto sampling = options.generator.sampling.value_or(SamplingOptions{});

    std::unique_ptr<IPromptDirectory> prompt_directory;

    if (!options.generator.use_mocked) {
      try {
        prompt_directory = std::make_unique<PromptDirectory>(
            options.pipeline.prompt_dir, log_producer);
      } catch (const std::exception& dir_error) {
        log_producer->Log(LogLevel::Error, PipelinePhase::Startup,
                          fmt::format("Invalid --prompt-dir: {}", dir_error.what()));
        return shutdown(1);
      }
    }

    const auto injector = di::make_injector(
        di::bind<ILogger>().to(log_producer),
        di::bind<ApplicationOptions>().to(options),
        di::bind<std::string>().to(model_path),
        di::bind<IExportService>().to<SqliteExportService>(),
        di::bind<IPromptFormatter>().to(
            [options, log_producer] {
              if (options.generator.use_mocked) {
                log_producer->Log(LogLevel::Info, PipelinePhase::Startup,
                                  "Prompt formatter: none (mock mode)");
                return std::unique_ptr<IPromptFormatter>(nullptr);
              }
              log_producer->Log(LogLevel::Info, PipelinePhase::Startup,
                                "Prompt formatter: Gemma4JinjaPromptFormatter");
              return std::unique_ptr<IPromptFormatter>(
                  std::make_unique<Gemma4JinjaPromptFormatter>());
            }),
        di::bind<WebClient>().to([options, log_producer] {
          if (options.generator.use_mocked) {
            log_producer->Log(LogLevel::Info, PipelinePhase::Startup,
                              "Web client: none (mock mode)");
            return std::unique_ptr<WebClient>(nullptr);
          }
          log_producer->Log(LogLevel::Info, PipelinePhase::Startup,
                            "Web client: HttpWebClient");
          return std::unique_ptr<WebClient>(
              std::make_unique<HttpWebClient>(log_producer));
        }),
        di::bind<IEnrichmentService>().to(
            [options, &log_producer](
                const auto& inj) -> std::unique_ptr<IEnrichmentService> {
              if (options.generator.use_mocked) {
                log_producer->Log(LogLevel::Info, PipelinePhase::Startup,
                                  "Enrichment: mock");
                return std::make_unique<MockEnrichmentService>();
              }
              log_producer->Log(LogLevel::Info, PipelinePhase::Startup,
                                "Enrichment: Wikipedia");
              return std::make_unique<WikipediaEnrichmentService>(
                  inj.template create<std::unique_ptr<WebClient>>(),
                  log_producer);
            }),
        di::bind<DataGenerator>().to(
            [&options, &model_path, &sampling, &prompt_directory,
             &log_producer](const auto& inj) -> std::unique_ptr<DataGenerator> {
              if (options.generator.use_mocked) {
                log_producer->Log(LogLevel::Info, PipelinePhase::Startup,
                                  "Generator: mock");
                return std::make_unique<MockGenerator>();
              }
              log_producer->Log(
                  LogLevel::Info, PipelinePhase::Startup,
                  fmt::format(
                      "Generator: LlamaGenerator | model={} | temp={:.2f} top_p={:.2f} top_k={} n_ctx={} seed={}",
                      model_path,
                      sampling.temperature,
                      sampling.top_p,
                      sampling.top_k,
                      sampling.n_ctx,
                      sampling.seed));
              return std::make_unique<LlamaGenerator>(
                  options, model_path, log_producer,
                  inj.template create<std::unique_ptr<IPromptFormatter>>(),
                  std::move(prompt_directory));
            }));

    const auto orchestrator =
        injector.create<std::unique_ptr<BiergartenPipelineOrchestrator>>();

    if (!orchestrator->Run()) {
      log_producer->Log(LogLevel::Error, PipelinePhase::Teardown,
                        "Pipeline execution failed");
      return shutdown(1);
    }

    log_producer->Log(LogLevel::Info, PipelinePhase::Teardown,
                      fmt::format("Pipeline complete in {} ms", timer.Elapsed()));

    return shutdown(0);

  } catch (const std::exception& exception) {
    if (log_producer) {
      log_producer->Log(LogLevel::Error, PipelinePhase::Teardown,
                        fmt::format("Unhandled fatal error: {}", exception.what()));
    }
    return shutdown(1);
  }
}