use std::{collections::HashMap, path::Path};

use indicatif::{ProgressBar, ProgressStyle};

use crate::{
  cli::UpdateArgs,
  error::{MultiError, PakkerError},
  model::{Config, LockFile, UpdateStrategy},
  platform::create_platform,
  ui_utils::{prompt_select, prompt_typo_suggestion, prompt_yes_no},
};

pub async fn execute(
  args: UpdateArgs,
  lockfile_path: &Path,
  config_path: &Path,
) -> Result<(), PakkerError> {
  // Load expects directory path, so get parent directory
  let lockfile_dir = lockfile_path.parent().unwrap_or(Path::new("."));
  let config_dir = config_path.parent().unwrap_or(Path::new("."));

  let mut lockfile = LockFile::load(lockfile_dir)?;
  let _config = Config::load(config_dir)?;

  // Create platforms
  let mut platforms = HashMap::new();
  if let Ok(platform) = create_platform("modrinth", None) {
    platforms.insert("modrinth".to_string(), platform);
  }
  if let Ok(platform) =
    create_platform("curseforge", std::env::var("CURSEFORGE_API_KEY").ok())
  {
    platforms.insert("curseforge".to_string(), platform);
  }

  // Collect all known project identifiers for typo suggestions
  let all_slugs: Vec<String> = lockfile
    .projects
    .iter()
    .flat_map(|p| {
      let mut ids = Vec::new();
      if let Some(ref pakku_id) = p.pakku_id {
        ids.push(pakku_id.clone());
      }
      ids.extend(p.slug.values().cloned());
      ids.extend(p.name.values().cloned());
      ids.extend(p.aliases.iter().cloned());
      ids
    })
    .collect();

  let project_indices: Vec<_> = if args.inputs.is_empty() {
    (0..lockfile.projects.len()).collect()
  } else {
    let mut indices = Vec::new();
    for input in &args.inputs {
      if let Some((idx, _)) = lockfile
        .projects
        .iter()
        .enumerate()
        .find(|(_, p)| p.matches_input(input))
      {
        indices.push(idx);
      } else {
        // Try typo suggestion
        if let Ok(Some(suggestion)) = prompt_typo_suggestion(input, &all_slugs)
          && let Some((idx, _)) = lockfile
            .projects
            .iter()
            .enumerate()
            .find(|(_, p)| p.matches_input(&suggestion))
        {
          log::info!("Using suggested project: {suggestion}");
          indices.push(idx);
          continue;
        }
        return Err(PakkerError::ProjectNotFound(input.clone()));
      }
    }
    indices
  };

  // Capture count before consuming the iterator
  let total_projects = project_indices.len();

  // Create progress bar
  let pb = ProgressBar::new(total_projects as u64);
  pb.set_style(
    ProgressStyle::default_bar()
      .template("{spinner:.green} [{bar:40.cyan/blue}] {pos}/{len} {msg}")
      .unwrap()
      .progress_chars("#>-"),
  );

  let mut skipped_pinned = 0;
  let mut update_errors = MultiError::new();

  for idx in project_indices {
    let old_project = &lockfile.projects[idx];

    // Skip projects with UpdateStrategy::None (pinned)
    if old_project.update_strategy == UpdateStrategy::None {
      pb.println(format!(
        "  {} - Skipped (update strategy: NONE)",
        old_project.get_name()
      ));
      skipped_pinned += 1;
      pb.inc(1);
      continue;
    }

    pb.set_message(format!("Updating {}...", old_project.get_name()));

    let slug = old_project
      .slug
      .values()
      .next()
      .ok_or_else(|| PakkerError::InvalidProject("No slug found".into()))?;

    // Find updated project from one of the platforms
    let mut updated_project = None;
    for platform in platforms.values() {
      if let Ok(project) = platform
        .request_project_with_files(
          slug,
          &lockfile.mc_versions,
          &lockfile.loaders.keys().cloned().collect::<Vec<_>>(),
        )
        .await
      {
        updated_project = Some(project);
        break;
      }
    }

    if updated_project.is_none() {
      // Failed to fetch update info from any platform
      update_errors.push(PakkerError::PlatformApiError(format!(
        "Failed to check updates for '{}'",
        old_project.get_name()
      )));
      pb.inc(1);
      continue;
    }

    if let Some(mut updated_project) = updated_project
      && !updated_project.files.is_empty()
      && let Some(old_file) = lockfile.projects[idx].files.first()
    {
      // Clone data needed for comparisons to avoid borrow issues
      let new_file_id = updated_project.files.first().unwrap().id.clone();
      let new_file_name =
        updated_project.files.first().unwrap().file_name.clone();
      let old_file_name = old_file.file_name.clone();
      let project_name = old_project.get_name();

      if new_file_id == old_file.id {
        pb.println(format!("  {project_name} - Already up to date"));
      } else {
        // Interactive confirmation and version selection if not using --yes
        // flag
        let mut should_update = args.yes || args.all;
        let mut selected_idx: Option<usize> = None;

        if !args.yes && !args.all {
          pb.suspend(|| {
            // First, confirm the update
            let prompt_msg = format!(
              "Update '{project_name}' from {old_file_name} to \
               {new_file_name}?"
            );
            should_update = prompt_yes_no(&prompt_msg, true).unwrap_or(false);

            // If confirmed and multiple versions available, offer selection
            if should_update && updated_project.files.len() > 1 {
              let choices: Vec<String> = updated_project
                .files
                .iter()
                .map(|f| format!("{} ({})", f.file_name, f.id))
                .collect();

              let choice_refs: Vec<&str> =
                choices.iter().map(std::string::String::as_str).collect();

              if let Ok(idx) = prompt_select(
                &format!("Select version for {project_name}:"),
                &choice_refs,
              ) {
                selected_idx = Some(idx);
              }
            }
          });
        }

        // Apply file selection outside the closure
        if let Some(idx) = selected_idx
          && idx > 0
        {
          updated_project.files.swap(0, idx);
        }

        if should_update {
          let selected_file = updated_project.files.first().unwrap();
          pb.println(format!(
            "  {} -> {}",
            old_file_name, selected_file.file_name
          ));
          lockfile.projects[idx] = updated_project;
        } else {
          pb.println(format!("  {project_name} - Skipped by user"));
        }
      }
    }
    pb.inc(1);
  }

  if skipped_pinned > 0 {
    pb.finish_with_message(format!(
      "Update complete ({skipped_pinned} pinned projects skipped)"
    ));
  } else {
    pb.finish_with_message("Update complete");
  }
  lockfile.save(lockfile_dir)?;

  // Report any errors that occurred during updates
  if !update_errors.is_empty() {
    let error_list = update_errors.errors();
    log::warn!(
      "{} project(s) encountered errors during update check",
      error_list.len()
    );
    for err in error_list {
      log::warn!("  - {err}");
    }

    // Extend with any additional collected errors and check if we should fail
    let all_errors = update_errors.into_errors();
    if all_errors.len() == total_projects {
      // All projects failed - return error
      let mut multi = MultiError::new();
      multi.extend(all_errors);
      return multi.into_result(());
    }
  }

  Ok(())
}