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

use indicatif::{ProgressBar, ProgressStyle};
use yansi::Paint;

use crate::{
  error::{PakkerError, Result},
  model::{
    Config,
    LockFile,
    Project,
    credentials::ResolvedCredentials,
    enums::{ProjectSide, ProjectType, UpdateStrategy},
  },
  platform::create_platform,
  resolver::DependencyResolver,
  ui_utils::prompt_curseforge_api_key,
};

/// Parse a common project argument (slug or ID with optional file ID)
/// Format: "input" or "`input#file_id`"
fn parse_common_arg(input: &str) -> (String, Option<String>) {
  if let Some((project_input, file_id)) = input.split_once('#') {
    (project_input.to_string(), Some(file_id.to_string()))
  } else {
    (input.to_string(), None)
  }
}

/// Parse a GitHub argument (owner/repo with optional tag)
/// Format: "owner/repo" or "owner/repo#tag"
fn parse_github_arg(input: &str) -> Result<(String, String, Option<String>)> {
  let (repo_part, tag) = if let Some((r, t)) = input.split_once('#') {
    (r, Some(t.to_string()))
  } else {
    (input, None)
  };

  if let Some((owner, repo)) = repo_part.split_once('/') {
    Ok((owner.to_string(), repo.to_string(), tag))
  } else {
    Err(PakkerError::InvalidInput(format!(
      "Invalid GitHub format '{input}'. Expected: owner/repo or owner/repo#tag"
    )))
  }
}

fn get_loaders(lockfile: &LockFile) -> Vec<String> {
  lockfile.loaders.keys().cloned().collect()
}

#[expect(
  clippy::future_not_send,
  reason = "not required to be Send; only called from single-threaded context"
)]
#[expect(
  clippy::too_many_arguments,
  reason = "CLI command handler maps directly from clap args"
)]
pub async fn execute(
  cf_arg: Option<String>,
  mr_arg: Option<String>,
  gh_arg: Option<String>,
  project_type: Option<ProjectType>,
  project_side: Option<ProjectSide>,
  update_strategy: Option<UpdateStrategy>,
  redistributable: Option<bool>,
  subpath: Option<String>,
  aliases: Vec<String>,
  export: Option<bool>,
  no_deps: bool,
  yes: bool,
  lockfile_path: &Path,
  config_path: &Path,
) -> Result<()> {
  // At least one platform must be specified
  if cf_arg.is_none() && mr_arg.is_none() && gh_arg.is_none() {
    return Err(PakkerError::InvalidInput(
      "At least one platform must be specified (--cf, --mr, or --gh)"
        .to_string(),
    ));
  }

  log::info!("Adding project with explicit platform specification");

  // Load lockfile
  let lockfile_dir = lockfile_path.parent().unwrap_or_else(|| Path::new("."));
  let config_dir = config_path.parent().unwrap_or_else(|| Path::new("."));

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

  // Load config if available
  let _config = Config::load(config_dir).ok();

  // Get MC versions and loaders from lockfile
  let mc_versions = &lockfile.mc_versions;
  let loaders = get_loaders(&lockfile);

  // Fetch projects from each specified platform
  let mut projects_to_merge: Vec<Project> = Vec::new();

  // CurseForge
  if let Some(cf_input) = cf_arg {
    log::info!("Fetching from CurseForge: {cf_input}");
    let (input, file_id) = parse_common_arg(&cf_input);

    let credentials = ResolvedCredentials::load();
    let mut cf_api_key = credentials.curseforge_api_key().map(String::from);

    // Prompt for missing CurseForge credentials
    if cf_api_key.is_none() && !yes {
      if let Some(key) = prompt_curseforge_api_key(false)? {
        cf_api_key = Some(key);
      }
    }

    let platform = create_platform("curseforge", cf_api_key)?;

    let spinner = ProgressBar::new_spinner();
    spinner.set_style(
      ProgressStyle::default_spinner()
        .template("{spinner:.green} {msg}")
        .expect("spinner template is valid"),
    );
    spinner.enable_steady_tick(Duration::from_millis(80));
    spinner.set_message("Fetching from CurseForge...");

    let mut project = platform
      .request_project_with_files(&input, mc_versions, &loaders)
      .await
      .map_err(|e| {
        PakkerError::ProjectNotFound(format!(
          "CurseForge project '{input}': {e}"
        ))
      })?;

    spinner.finish_and_clear();

    // If file_id specified, filter to that file
    if let Some(fid) = file_id {
      project.files.retain(|f| f.id == fid);
      if project.files.is_empty() {
        return Err(PakkerError::FileSelectionError(format!(
          "File ID '{fid}' not found for CurseForge project '{input}'"
        )));
      }
    }

    projects_to_merge.push(project);
    spinner.finish_and_clear();
  }

  // Modrinth
  if let Some(mr_input) = mr_arg {
    log::info!("Fetching from Modrinth: {mr_input}");
    let (input, file_id) = parse_common_arg(&mr_input);

    let platform = create_platform("modrinth", None)?;

    let spinner = ProgressBar::new_spinner();
    spinner.set_style(
      ProgressStyle::default_spinner()
        .template("{spinner:.green} {msg}")
        .expect("spinner template is valid"),
    );
    spinner.enable_steady_tick(Duration::from_millis(80));
    spinner.set_message("Fetching from Modrinth...");

    let mut project = platform
      .request_project_with_files(&input, mc_versions, &loaders)
      .await
      .map_err(|e| {
        PakkerError::ProjectNotFound(format!("Modrinth project '{input}': {e}"))
      })?;

    // If file_id specified, filter to that file
    if let Some(fid) = file_id {
      project.files.retain(|f| f.id == fid);
      if project.files.is_empty() {
        return Err(PakkerError::FileSelectionError(format!(
          "File ID '{fid}' not found for Modrinth project '{input}'"
        )));
      }
    }

    spinner.finish_and_clear();
    projects_to_merge.push(project);
  }

  // GitHub
  if let Some(gh_input) = gh_arg {
    log::info!("Fetching from GitHub: {gh_input}");
    let (owner, repo, tag) = parse_github_arg(&gh_input)?;

    let gh_token = std::env::var("GITHUB_TOKEN").ok();
    let platform = create_platform("github", gh_token)?;

    let spinner = ProgressBar::new_spinner();
    spinner.set_style(
      ProgressStyle::default_spinner()
        .template("{spinner:.green} {msg}")
        .expect("spinner template is valid"),
    );
    spinner.enable_steady_tick(Duration::from_millis(80));
    spinner.set_message("Fetching from GitHub...");

    let repo_path = format!("{owner}/{repo}");
    let mut project = platform
      .request_project_with_files(&repo_path, mc_versions, &loaders)
      .await
      .map_err(|e| {
        PakkerError::ProjectNotFound(format!(
          "GitHub repository '{owner}/{repo}': {e}"
        ))
      })?;

    // If tag specified, filter to that tag
    if let Some(t) = tag {
      project.files.retain(|f| f.id == t);
      if project.files.is_empty() {
        return Err(PakkerError::FileSelectionError(format!(
          "Tag '{t}' not found for GitHub repository '{owner}/{repo}'"
        )));
      }
    }

    spinner.finish_and_clear();
    projects_to_merge.push(project);
  }

  // Merge all fetched projects into one
  if projects_to_merge.is_empty() {
    return Err(PakkerError::ProjectNotFound(
      "No projects could be fetched from specified platforms".to_string(),
    ));
  }

  let mut combined_project = projects_to_merge.remove(0);
  for project in projects_to_merge {
    combined_project.merge(project);
  }

  // Apply user-specified properties
  if let Some(pt) = project_type {
    combined_project.r#type = pt;
  }
  if let Some(ps) = project_side {
    combined_project.side = ps;
  }
  if let Some(us) = update_strategy {
    combined_project.update_strategy = us;
  }
  if let Some(r) = redistributable {
    combined_project.redistributable = r;
  }
  if let Some(sp) = subpath {
    combined_project.subpath = Some(sp);
  }
  if let Some(e) = export {
    combined_project.export = e;
  }

  // Add aliases
  for alias in aliases {
    combined_project.aliases.insert(alias);
  }

  // Check if project already exists
  let existing_pos = lockfile.projects.iter().position(|p| {
    // Check if any platform ID matches
    combined_project.id.iter().any(|(platform, id)| {
      p.id
        .get(platform)
        .is_some_and(|existing_id| existing_id == id)
    })
  });

  let project_name = combined_project.get_name();

  if let Some(pos) = existing_pos {
    let existing_project = &lockfile.projects[pos];
    let existing_name = existing_project.get_name();

    if !yes {
      let prompt_msg = format!(
        "Project '{existing_name}' already exists. Replace with \
         '{project_name}'?"
      );
      if !crate::ui_utils::prompt_yes_no(&prompt_msg, false, yes)? {
        log::info!("Operation cancelled by user");
        return Ok(());
      }
    }

    log::info!("Replacing existing project: {existing_name}");
    lockfile.projects[pos] = combined_project.clone();
    println!(
      "{}",
      format!("✓ Replaced '{existing_name}' with '{project_name}'").green()
    );
  } else {
    if !yes {
      let prompt_msg = format!("Add project '{project_name}'?");
      if !crate::ui_utils::prompt_yes_no(&prompt_msg, true, yes)? {
        log::info!("Operation cancelled by user");
        return Ok(());
      }
    }

    lockfile.add_project(combined_project.clone());
    println!("{}", format!("✓ Added '{project_name}'").green());
  }

  // Resolve dependencies unless --no-deps is specified
  if !no_deps {
    log::info!("Resolving dependencies...");

    let dep_spinner = ProgressBar::new_spinner();
    dep_spinner.set_style(
      ProgressStyle::default_spinner()
        .template("{spinner:.green} {msg}")
        .expect("spinner template is valid"),
    );
    dep_spinner.enable_steady_tick(Duration::from_millis(80));
    dep_spinner.set_message("Resolving dependencies...");

    let platforms = create_all_platforms();
    let mut resolver = DependencyResolver::new();

    let deps = resolver
      .resolve(&mut combined_project, &mut lockfile, &platforms)
      .await?;

    dep_spinner.finish_and_clear();

    for dep in deps {
      // Skip if already in lockfile
      if lockfile.projects.iter().any(|p| {
        dep.id.iter().any(|(platform, id)| {
          p.id
            .get(platform)
            .is_some_and(|existing_id| existing_id == id)
        })
      }) {
        continue;
      }

      let dep_name = dep.get_name();

      // Prompt user for confirmation unless --yes flag is set
      if !yes {
        let prompt_msg =
          format!("Add dependency '{dep_name}' required by '{project_name}'?");
        if !crate::ui_utils::prompt_yes_no(&prompt_msg, true, yes)? {
          log::info!("Skipping dependency: {dep_name}");
          continue;
        }
      }

      log::info!("Adding dependency: {dep_name}");
      lockfile.add_project(dep);
      println!("{}", format!("  ✓ Added dependency '{dep_name}'").green());
    }
  }

  // Save lockfile
  lockfile.save(lockfile_dir)?;

  log::info!("Successfully completed add-prj operation");

  Ok(())
}

fn create_all_platforms()
-> HashMap<String, Box<dyn crate::platform::PlatformClient>> {
  let mut platforms = HashMap::new();

  let credentials = ResolvedCredentials::load();
  let curseforge_key = credentials.curseforge_api_key().map(String::from);
  let github_token = credentials.github_access_token().map(String::from);

  if let Ok(platform) = create_platform("multiplatform", curseforge_key) {
    platforms.insert("multiplatform".to_string(), platform);
  } else if let Ok(platform) = create_platform("modrinth", None) {
    platforms.insert("modrinth".to_string(), platform);
  }
  if let Ok(platform) = create_platform("github", github_token) {
    platforms.insert("github".to_string(), platform);
  }

  platforms
}

#[cfg(test)]
mod tests {
  use super::*;

  #[test]
  fn test_parse_common_arg_without_file_id() {
    let (input, file_id) = parse_common_arg("fabric-api");
    assert_eq!(input, "fabric-api");
    assert_eq!(file_id, None);
  }

  #[test]
  fn test_parse_common_arg_with_file_id() {
    let (input, file_id) = parse_common_arg("fabric-api#12345");
    assert_eq!(input, "fabric-api");
    assert_eq!(file_id, Some("12345".to_string()));
  }

  #[test]
  fn test_parse_github_arg_owner_repo() {
    let result = parse_github_arg("FabricMC/fabric");
    assert!(result.is_ok());
    let (owner, repo, tag) = result.unwrap();
    assert_eq!(owner, "FabricMC");
    assert_eq!(repo, "fabric");
    assert_eq!(tag, None);
  }

  #[test]
  fn test_parse_github_arg_with_tag() {
    let result = parse_github_arg("FabricMC/fabric#v0.15.0");
    assert!(result.is_ok());
    let (owner, repo, tag) = result.unwrap();
    assert_eq!(owner, "FabricMC");
    assert_eq!(repo, "fabric");
    assert_eq!(tag, Some("v0.15.0".to_string()));
  }

  #[test]
  fn test_parse_github_arg_invalid() {
    let result = parse_github_arg("invalid-format");
    assert!(result.is_err());
    assert!(
      result
        .unwrap_err()
        .to_string()
        .contains("Invalid GitHub format")
    );
  }

  #[test]
  fn test_parse_github_arg_missing_repo() {
    let result = parse_github_arg("FabricMC/");
    assert!(result.is_ok());
    let (owner, repo, tag) = result.unwrap();
    assert_eq!(owner, "FabricMC");
    assert_eq!(repo, "");
    assert_eq!(tag, None);
  }
}