use clap::Args;
use indexmap::{IndexMap, IndexSet};
use mozart_core::console::Verbosity;
use mozart_core::console_format;
use mozart_core::package::{self, Stability};
use mozart_core::validation;
use mozart_registry::lockfile;
use mozart_registry::packagist;
use mozart_registry::resolver::{self, PlatformConfig, ResolveRequest};
use mozart_registry::version;
use std::io::{BufRead, IsTerminal, Write};

#[derive(Args)]
pub struct RequireArgs {
    /// Package(s) to require
    pub packages: Vec<String>,

    /// Add requirement to require-dev
    #[arg(long)]
    pub dev: bool,

    /// Only output what would be changed, do not modify files
    #[arg(long)]
    pub dry_run: bool,

    /// Forces installation from package sources when possible
    #[arg(long)]
    pub prefer_source: bool,

    /// Forces installation from package dist
    #[arg(long)]
    pub prefer_dist: bool,

    /// Forces usage of a specific install method (dist, source, auto)
    #[arg(long)]
    pub prefer_install: Option<String>,

    /// Pin the exact version instead of a range
    #[arg(long)]
    pub fixed: bool,

    /// [Deprecated] Do not show install suggestions
    #[arg(long)]
    pub no_suggest: bool,

    /// Do not output download progress
    #[arg(long)]
    pub no_progress: bool,

    /// Disables the automatic update of the lock file
    #[arg(long)]
    pub no_update: bool,

    /// Skip the install step
    #[arg(long)]
    pub no_install: bool,

    /// Skip the audit step
    #[arg(long)]
    pub no_audit: bool,

    /// Audit output format
    #[arg(long, value_parser = ["table", "plain", "json", "summary"])]
    pub audit_format: Option<String>,

    /// Do not block on security advisories
    #[arg(long)]
    pub no_security_blocking: bool,

    /// Run the dependency update with the --no-dev option
    #[arg(long)]
    pub update_no_dev: bool,

    /// [Deprecated] Use --with-dependencies instead
    #[arg(short = 'w', long)]
    pub update_with_dependencies: bool,

    /// [Deprecated] Use --with-all-dependencies instead
    #[arg(short = 'W', long)]
    pub update_with_all_dependencies: bool,

    /// Update also dependencies of newly required packages
    #[arg(long)]
    pub with_dependencies: bool,

    /// Update all dependencies including root requirements
    #[arg(long)]
    pub with_all_dependencies: bool,

    /// Ignore a specific platform requirement
    #[arg(long)]
    pub ignore_platform_req: Vec<String>,

    /// Ignore all platform requirements
    #[arg(long)]
    pub ignore_platform_reqs: bool,

    /// Prefer stable versions of dependencies
    #[arg(long)]
    pub prefer_stable: bool,

    /// Prefer lowest versions of dependencies
    #[arg(long)]
    pub prefer_lowest: bool,

    /// Prefer minimal restriction updates
    #[arg(short = 'm', long)]
    pub minimal_changes: bool,

    /// Sort packages in composer.json
    #[arg(long)]
    pub sort_packages: bool,

    /// Optimizes PSR-0 and PSR-4 packages to be loaded with classmaps
    #[arg(short, long)]
    pub optimize_autoloader: bool,

    /// Autoload classes from the classmap only
    #[arg(short = 'a', long)]
    pub classmap_authoritative: bool,

    /// Use APCu to cache found/not-found classes
    #[arg(long)]
    pub apcu_autoloader: bool,

    /// Use a custom prefix for the APCu autoloader cache
    #[arg(long)]
    pub apcu_autoloader_prefix: Option<String>,
}

/// Run the interactive package search+pick loop.
///
/// Returns a list of `"vendor/package:constraint"` strings that the user confirmed,
/// or an empty vec if the user typed nothing / pressed Ctrl-D immediately.
async fn interactive_search_packages(
    already_required: &indexmap::IndexSet<String>,
    preferred_stability: Stability,
    fixed: bool,
    repo_cache: &mozart_registry::cache::Cache,
    console: &mozart_core::console::Console,
) -> anyhow::Result<Vec<String>> {
    let stdin = std::io::stdin();
    if !stdin.is_terminal() {
        anyhow::bail!(
            "Not enough arguments (missing: \"packages\") and stdin is not a TTY. \
             Pass package name(s) directly or run interactively."
        );
    }

    let mut selected: Vec<String> = Vec::new();

    loop {
        // Prompt for a search query (empty input = done)
        eprint!("Search for a package: ");
        let _ = std::io::stderr().flush();

        let query = {
            let stdin_locked = stdin.lock();
            let mut lines = stdin_locked.lines();
            match lines.next() {
                Some(Ok(line)) => line.trim().to_string(),
                _ => break, // EOF or error
            }
        };

        if query.is_empty() {
            break;
        }

        // Search Packagist
        let (results, total) = match packagist::search_packages(&query, None).await {
            Ok(r) => r,
            Err(e) => {
                console.info(&console_format!(
                    "<warning>Search failed: {e}. Try again.</warning>"
                ));
                continue;
            }
        };

        // Filter out packages already in require / require-dev
        let filtered: Vec<&packagist::SearchResult> = results
            .iter()
            .filter(|r| !already_required.contains(&r.name.to_lowercase()))
            .take(15)
            .collect();

        if filtered.is_empty() {
            console.info(&console_format!(
                "<warning>No new packages found for \"{query}\" (total: {total}).</warning>"
            ));
            continue;
        }

        console.info(&format!(
            "\nFound {} package{} for \"{}\":",
            filtered.len(),
            if filtered.len() == 1 { "" } else { "s" },
            query
        ));

        let name_width = filtered.iter().map(|r| r.name.len()).max().unwrap_or(0);
        for (idx, result) in filtered.iter().enumerate() {
            let desc = if result.description.is_empty() {
                String::new()
            } else {
                format!(" — {}", result.description)
            };
            console.info(&format!(
                "  [{idx}] {:<width$}{desc}",
                result.name,
                idx = idx + 1,
                width = name_width,
            ));
        }
        console.info("  [0] Search again / enter full package name");
        console.info("");

        // Ask user to pick
        eprint!("Enter package # or name (leave empty to finish): ");
        let _ = std::io::stderr().flush();

        let choice = {
            let stdin_locked = stdin.lock();
            let mut lines = stdin_locked.lines();
            match lines.next() {
                Some(Ok(line)) => line.trim().to_string(),
                _ => break,
            }
        };

        if choice.is_empty() {
            // Empty = done
            break;
        }

        // Resolve the chosen package name
        let package_name: String = if let Ok(num) = choice.parse::<usize>() {
            if num == 0 {
                // Search again
                continue;
            } else if num <= filtered.len() {
                filtered[num - 1].name.to_lowercase()
            } else {
                console.info(&console_format!(
                    "<warning>Invalid selection: {num}</warning>"
                ));
                continue;
            }
        } else {
            // User typed a full package name (possibly with constraint)
            choice.to_lowercase()
        };

        // Determine constraint
        let (pkg_name, constraint) = if package_name.contains(':') {
            match validation::parse_require_string(&package_name) {
                Ok((n, v)) => (n.to_lowercase(), v),
                Err(e) => {
                    console.info(&console_format!("<warning>Invalid: {e}</warning>"));
                    continue;
                }
            }
        } else {
            if !validation::validate_package_name(&package_name) {
                console.info(&console_format!(
                    "<warning>Invalid package name: \"{package_name}\"</warning>"
                ));
                continue;
            }

            console.info(&console_format!(
                "<info>Using version constraint for {package_name} from Packagist...</info>"
            ));

            match packagist::fetch_package_versions(&package_name, repo_cache).await {
                Ok(versions) => {
                    match version::find_best_candidate(&versions, preferred_stability) {
                        Some(best) => {
                            let stability = version::stability_of(&best.version_normalized);
                            let c = if fixed {
                                best.version.clone()
                            } else {
                                version::find_recommended_require_version(
                                    &best.version,
                                    &best.version_normalized,
                                    stability,
                                )
                            };
                            console.info(&console_format!(
                                "<info>Using version {c} for {package_name}</info>"
                            ));
                            (package_name, c)
                        }
                        None => {
                            console.info(&console_format!(
                                "<warning>Could not find a version of \"{package_name}\" matching your minimum-stability. Try specifying it explicitly.</warning>"
                            ));
                            continue;
                        }
                    }
                }
                Err(e) => {
                    console.info(&console_format!(
                        "<warning>Could not fetch versions for \"{package_name}\": {e}</warning>"
                    ));
                    continue;
                }
            }
        };

        selected.push(format!("{pkg_name}:{constraint}"));

        // Ask whether to add more
        eprint!("Search for another package? [y/N] ");
        let _ = std::io::stderr().flush();

        let again = {
            let stdin_locked = stdin.lock();
            let mut lines = stdin_locked.lines();
            match lines.next() {
                Some(Ok(line)) => line.trim().to_lowercase(),
                _ => break,
            }
        };

        if again != "y" && again != "yes" {
            break;
        }
    }

    Ok(selected)
}

pub async fn execute(
    args: &RequireArgs,
    cli: &super::Cli,
    console: &mozart_core::console::Console,
) -> anyhow::Result<()> {
    let cache_config = mozart_registry::cache::build_cache_config(cli.no_cache);
    let repo_cache = mozart_registry::cache::Cache::repo(&cache_config);

    // Collect the effective list of packages to add.
    // If none were provided on the CLI, try interactive search (unless --no-interaction).
    let cli_packages: Vec<String> = if args.packages.is_empty() {
        if cli.no_interaction {
            anyhow::bail!("Not enough arguments (missing: \"packages\").");
        }
        // Interactive search — we need composer.json first to know what's already required.
        // We'll perform a quick check that composer.json exists, then run the search.
        let working_dir = cli.working_dir()?;
        let composer_path = working_dir.join("composer.json");
        if !composer_path.exists() {
            anyhow::bail!(
                "composer.json not found in {}. Run `mozart init` to create one.",
                working_dir.display()
            );
        }
        let raw_check = package::read_from_file(&composer_path)?;

        // Build set of already-required packages
        let mut already_required: indexmap::IndexSet<String> = indexmap::IndexSet::new();
        for k in raw_check.require.keys() {
            already_required.insert(k.to_lowercase());
        }
        for k in raw_check.require_dev.keys() {
            already_required.insert(k.to_lowercase());
        }

        let preferred_stability = raw_check
            .minimum_stability
            .as_deref()
            .map(|s| match s.to_lowercase().as_str() {
                "dev" => Stability::Dev,
                "alpha" => Stability::Alpha,
                "beta" => Stability::Beta,
                "rc" | "RC" => Stability::RC,
                _ => Stability::Stable,
            })
            .unwrap_or(Stability::Stable);

        let found = interactive_search_packages(
            &already_required,
            preferred_stability,
            args.fixed,
            &repo_cache,
            console,
        )
        .await?;

        if found.is_empty() {
            // Nothing selected — exit cleanly
            return Ok(());
        }

        found
    } else {
        args.packages.clone()
    };

    // Handle deprecated flags
    if args.no_suggest {
        console.info(&console_format!(
            "<warning>The --no-suggest option is deprecated and has no effect.</warning>"
        ));
    }
    if args.update_with_dependencies {
        console.info(&console_format!("<warning>The -w / --update-with-dependencies flag is deprecated. Use --with-dependencies instead.</warning>"));
    }
    if args.update_with_all_dependencies {
        console.info(&console_format!("<warning>The -W / --update-with-all-dependencies flag is deprecated. Use --with-all-dependencies instead.</warning>"));
    }

    let working_dir = cli.working_dir()?;

    let composer_path = working_dir.join("composer.json");
    if !composer_path.exists() {
        anyhow::bail!(
            "composer.json not found in {}. Run `mozart init` to create one.",
            working_dir.display()
        );
    }

    // Read existing composer.json
    let mut raw = package::read_from_file(&composer_path)?;

    // Backup original composer.json content for revert on failure
    let original_composer_json = std::fs::read_to_string(&composer_path)?;

    // Backup composer.lock content if it exists
    let lock_path_for_backup = working_dir.join("composer.lock");
    let original_composer_lock = if lock_path_for_backup.exists() {
        Some(std::fs::read_to_string(&lock_path_for_backup)?)
    } else {
        None
    };

    // Determine preferred stability from composer.json's minimum-stability
    let preferred_stability = raw
        .minimum_stability
        .as_deref()
        .map(|s| match s.to_lowercase().as_str() {
            "dev" => Stability::Dev,
            "alpha" => Stability::Alpha,
            "beta" => Stability::Beta,
            "rc" | "RC" => Stability::RC,
            _ => Stability::Stable,
        })
        .unwrap_or(Stability::Stable);

    // Process each package argument
    let mut additions: Vec<(String, String, bool)> = Vec::new(); // (name, constraint, is_dev)

    for pkg_arg in &cli_packages {
        // Try to parse as "vendor/package:constraint"
        let (name, constraint) = match validation::parse_require_string(pkg_arg) {
            Ok((n, v)) => (n.to_lowercase(), v),
            Err(_) => {
                // No version specified — resolve from Packagist
                let name = pkg_arg.trim().to_lowercase();
                if !validation::validate_package_name(&name) {
                    anyhow::bail!("Invalid package name: \"{name}\"");
                }

                console.write_stdout(
                    &console_format!(
                        "<info>Using version constraint for {name} from Packagist...</info>"
                    ),
                    Verbosity::Normal,
                );

                let versions = packagist::fetch_package_versions(&name, &repo_cache).await?;
                let best = version::find_best_candidate(&versions, preferred_stability)
                    .ok_or_else(|| {
                        anyhow::anyhow!(
                            "Could not find a version of package \"{name}\" matching your minimum-stability ({preferred_stability:?}). \
                             Try requiring it with an explicit version constraint."
                        )
                    })?;

                let stability = version::stability_of(&best.version_normalized);
                let constraint = if args.fixed {
                    best.version.clone()
                } else {
                    version::find_recommended_require_version(
                        &best.version,
                        &best.version_normalized,
                        stability,
                    )
                };

                console.write_stdout(
                    &console_format!("<info>Using version {constraint} for {name}</info>"),
                    Verbosity::Normal,
                );

                (name, constraint)
            }
        };

        additions.push((name, constraint, args.dev));
    }

    // Fix 3: Self-require detection — block requiring the root package itself
    let root_name = raw.name.to_lowercase();
    for (name, _, _) in &additions {
        if name.to_lowercase() == root_name {
            anyhow::bail!(
                "Root package '{}' cannot require itself in its composer.json",
                raw.name
            );
        }
    }

    // Fix 2: Cross-section move detection — remove from opposite section if present
    for (name, _, is_dev) in &additions {
        if *is_dev {
            // Adding to require-dev: check require (prod)
            if raw.require.contains_key(name.as_str()) {
                console.info(&console_format!(
                    "<warning>{name} is currently present in the require key and will be moved to the require-dev key.</warning>"
                ));
                raw.require.remove(name.as_str());
            }
        } else {
            // Adding to require (prod): check require-dev
            if raw.require_dev.contains_key(name.as_str()) {
                console.info(&console_format!(
                    "<warning>{name} is currently present in the require-dev key and will be moved to the require key.</warning>"
                ));
                raw.require_dev.remove(name.as_str());
            }
        }
    }

    // Apply changes
    for (name, constraint, is_dev) in &additions {
        let section_name = if *is_dev { "require-dev" } else { "require" };
        let target = if *is_dev {
            &mut raw.require_dev
        } else {
            &mut raw.require
        };

        if let Some(existing) = target.get(name) {
            console.write_stdout(
                &console_format!(
                    "<comment>Updating {name} from {existing} to {constraint} in {section_name}</comment>"
                ),
                Verbosity::Normal,
            );
        } else {
            console.write_stdout(
                &console_format!("<info>Adding {name} ({constraint}) to {section_name}</info>"),
                Verbosity::Normal,
            );
        }

        target.insert(name.clone(), constraint.clone());
    }

    // Fix 5: sort-packages config integration — also check config.sort-packages from composer.json
    let config_sort_packages = raw
        .extra_fields
        .get("config")
        .and_then(|c| c.get("sort-packages"))
        .and_then(|v| v.as_bool())
        .unwrap_or(false);
    let sort_packages = args.sort_packages || config_sort_packages;

    // Sort packages if requested (via CLI flag or composer.json config)
    if sort_packages {
        let sorted_require: std::collections::BTreeMap<_, _> = raw.require.clone();
        raw.require = sorted_require;
        let sorted_dev: std::collections::BTreeMap<_, _> = raw.require_dev.clone();
        raw.require_dev = sorted_dev;
    }

    // Write back composer.json (unless --dry-run)
    if args.dry_run {
        console.write_stdout(
            &console_format!("<comment>Dry run: composer.json not modified.</comment>"),
            Verbosity::Normal,
        );
    } else {
        package::write_to_file(&raw, &composer_path)?;
    }

    // Handle --no-update: skip resolution entirely
    if args.no_update {
        console.write_stdout(
            &console_format!(
                "<comment>Not updating dependencies, only modifying composer.json.</comment>"
            ),
            Verbosity::Normal,
        );
        return Ok(());
    }

    // --- Full resolution + lock + install pipeline ---

    let dev_mode = !args.update_no_dev;
    let lock_path = working_dir.join("composer.lock");
    let vendor_dir = working_dir.join("vendor");

    // Build require/require_dev lists from the updated raw data
    let require: Vec<(String, String)> = raw
        .require
        .iter()
        .map(|(k, v)| (k.clone(), v.clone()))
        .collect();

    let require_dev: Vec<(String, String)> = raw
        .require_dev
        .iter()
        .map(|(k, v)| (k.clone(), v.clone()))
        .collect();

    // Parse minimum-stability from composer.json (defaults to "stable")
    let minimum_stability_str = raw.minimum_stability.as_deref().unwrap_or("stable");
    let minimum_stability = package::Stability::parse(minimum_stability_str);

    // Determine prefer-stable: CLI flag OR composer.json field
    let composer_prefer_stable = raw
        .extra_fields
        .get("prefer-stable")
        .and_then(|v| v.as_bool())
        .unwrap_or(false);
    let prefer_stable = args.prefer_stable || composer_prefer_stable;

    let request = ResolveRequest {
        root_name: raw.name.clone(),
        root_version: raw.version.clone(),
        require,
        require_dev,
        include_dev: dev_mode,
        minimum_stability,
        stability_flags: IndexMap::new(),
        prefer_stable,
        prefer_lowest: args.prefer_lowest,
        platform: PlatformConfig::new(),
        ignore_platform_reqs: args.ignore_platform_reqs,
        ignore_platform_req_list: args.ignore_platform_req.clone(),
        repositories: std::sync::Arc::new(
            mozart_registry::repository::RepositorySet::with_packagist(repo_cache.clone()),
        ),
        temporary_constraints: IndexMap::new(),
        raw_repositories: raw.repositories.clone(),
        root_provide: raw
            .provide
            .iter()
            .map(|(k, v)| (k.clone(), v.clone()))
            .collect(),
        root_replace: raw
            .replace
            .iter()
            .map(|(k, v)| (k.clone(), v.clone()))
            .collect(),
        root_conflict: raw
            .conflict
            .iter()
            .map(|(k, v)| (k.clone(), v.clone()))
            .collect(),
        locked_package_names: indexmap::IndexSet::new(),
        locked_packages: Vec::new(),
        block_abandoned: false,
        root_branch_alias: None,
        preferred_versions: indexmap::IndexMap::new(),
        block_insecure: false,
    };

    // Print header messages
    console.info("Loading composer repositories with package information");
    if dev_mode {
        console.info("Updating dependencies (including require-dev)");
    } else {
        console.info("Updating dependencies");
    }
    console.info("Resolving dependencies...");

    // Run resolver
    let mut resolved = match resolver::resolve(&request).await {
        Ok(packages) => packages,
        Err(e) => {
            // Fix 1: Revert composer.json (and composer.lock) on failure
            if !args.dry_run {
                console.write_error(
                    "Installation failed, reverting ./composer.json to its original content.",
                );
                if let Err(revert_err) = std::fs::write(&composer_path, &original_composer_json) {
                    console.write_error(&format!(
                        "Warning: Failed to revert composer.json: {revert_err}"
                    ));
                }
                if let Some(ref lock_content) = original_composer_lock
                    && let Err(revert_err) = std::fs::write(&lock_path_for_backup, lock_content)
                {
                    console.write_error(&format!(
                        "Warning: Failed to revert composer.lock: {revert_err}"
                    ));
                }
            }
            return Err(mozart_core::exit_code::bail(
                mozart_core::exit_code::DEPENDENCY_RESOLUTION_FAILED,
                e.to_string(),
            ));
        }
    };

    // Read old lock file (if any) for change reporting and partial update
    let old_lock = if lock_path.exists() {
        match lockfile::LockFile::read_from_file(&lock_path) {
            Ok(l) => Some(l),
            Err(e) => {
                console.info(&console_format!("<warning>Could not read existing composer.lock: {}. Treating as a fresh install.</warning>", e));
                None
            }
        }
    } else {
        None
    };

    // Apply --with-dependencies / --with-all-dependencies partial update logic.
    //
    // When a lock file exists, pin packages that are NOT in the allow list to their
    // locked versions to prevent unintended upgrades.
    let with_deps = args.with_dependencies || args.update_with_dependencies;
    let with_all_deps = args.with_all_dependencies || args.update_with_all_dependencies;

    if let Some(ref lock) = old_lock {
        // Build the allow list: newly required package names + (optionally) their deps.
        let newly_required: Vec<String> =
            additions.iter().map(|(name, _, _)| name.clone()).collect();

        let repo_requires = super::update::collect_repo_requires(&raw.repositories);
        let allow_list = if with_all_deps {
            super::update::expand_with_all_dependencies(newly_required, lock, &repo_requires)
        } else if with_deps {
            super::update::expand_with_direct_dependencies(
                newly_required,
                lock,
                &IndexSet::new(),
                &repo_requires,
            )
        } else {
            // Default for `require`: only the newly added packages are allowed to change.
            additions.iter().map(|(name, _, _)| name.clone()).collect()
        };

        resolved = super::update::apply_partial_update(resolved, lock, &allow_list);
    }

    // Get the composer.json content string for content-hash computation.
    // For --dry-run, serialize from memory; otherwise re-read the file we just wrote.
    let composer_json_content = if args.dry_run {
        package::to_json_pretty(&raw)?
    } else {
        std::fs::read_to_string(&composer_path)?
    };

    // Generate new lock file
    let new_lock = lockfile::generate_lock_file(&lockfile::LockFileGenerationRequest {
        resolved_packages: resolved,
        composer_json_content: composer_json_content.clone(),
        composer_json: raw.clone(),
        include_dev: dev_mode,
        repositories: std::sync::Arc::new(
            mozart_registry::repository::RepositorySet::with_packagist(repo_cache.clone()),
        ),
        previous_lock: old_lock.clone(),
        lock_pinned_names: indexmap::IndexSet::new(),
    })
    .await?;

    // Compute and print change report
    let changes = super::update::compute_update_changes(old_lock.as_ref(), &new_lock, dev_mode);

    let installs: Vec<_> = changes
        .iter()
        .filter(|c| matches!(c.kind, super::update::ChangeKind::Install { .. }))
        .collect();
    let updates: Vec<_> = changes
        .iter()
        .filter(|c| matches!(c.kind, super::update::ChangeKind::Update { .. }))
        .collect();
    let removals: Vec<_> = changes
        .iter()
        .filter(|c| matches!(c.kind, super::update::ChangeKind::Remove { .. }))
        .collect();

    console.info(&format!(
        "Package operations: {} install{}, {} update{}, {} removal{}",
        installs.len(),
        if installs.len() == 1 { "" } else { "s" },
        updates.len(),
        if updates.len() == 1 { "" } else { "s" },
        removals.len(),
        if removals.len() == 1 { "" } else { "s" },
    ));

    // Print individual change lines
    for change in &changes {
        match &change.kind {
            super::update::ChangeKind::Remove { old_version } => {
                if args.dry_run {
                    console.info(&format!(
                        "  - Would remove {} ({})",
                        change.name, old_version
                    ));
                } else {
                    console.info(&format!("  - Removing {} ({})", change.name, old_version));
                }
            }
            super::update::ChangeKind::Install { new_version } => {
                if args.dry_run {
                    console.info(&format!(
                        "  - Would install {} ({})",
                        change.name, new_version
                    ));
                } else {
                    console.info(&format!("  - Installing {} ({})", change.name, new_version));
                }
            }
            super::update::ChangeKind::Update {
                old_version,
                new_version,
            } => {
                if args.dry_run {
                    console.info(&format!(
                        "  - Would update {} ({} => {})",
                        change.name, old_version, new_version
                    ));
                } else {
                    console.info(&format!(
                        "  - Updating {} ({} => {})",
                        change.name, old_version, new_version
                    ));
                }
            }
            super::update::ChangeKind::Unchanged => {}
        }
    }

    // Write lock file (unless --dry-run)
    if !args.dry_run {
        console.info("Writing lock file");
        new_lock.write_to_file(&lock_path)?;
    }

    // Install packages (unless --no-install or --dry-run)
    if !args.no_install && !args.dry_run {
        // Warn about prefer-source (not yet supported)
        let prefer_source = args.prefer_source
            || args
                .prefer_install
                .as_deref()
                .map(|s| s.eq_ignore_ascii_case("source"))
                .unwrap_or(false);
        if prefer_source {
            console.info(&console_format!("<warning>Warning: Source installs are not yet supported. Falling back to dist.</warning>"));
        }

        // Fix 6: Read autoloader config settings from composer.json as defaults
        let composer_config = raw.extra_fields.get("config");
        let config_optimize = composer_config
            .and_then(|c| c.get("optimize-autoloader"))
            .and_then(|v| v.as_bool())
            .unwrap_or(false);
        let config_classmap = composer_config
            .and_then(|c| c.get("classmap-authoritative"))
            .and_then(|v| v.as_bool())
            .unwrap_or(false);
        let config_apcu = composer_config
            .and_then(|c| c.get("apcu-autoloader"))
            .and_then(|v| v.as_bool())
            .unwrap_or(false);

        let cache_config = mozart_registry::cache::build_cache_config(cli.no_cache);
        let files_cache = mozart_registry::cache::Cache::files(&cache_config);
        let mut executor =
            mozart_registry::installer_executor::FilesystemExecutor::new(files_cache);
        super::install::install_from_lock(
            &new_lock,
            &working_dir,
            &vendor_dir,
            &super::install::InstallConfig {
                dev_mode,
                dry_run: false,       // dry_run already handled above
                no_autoloader: false, // always generate autoloader
                no_progress: args.no_progress,
                ignore_platform_reqs: args.ignore_platform_reqs,
                ignore_platform_req: args.ignore_platform_req.clone(),
                // Fix 6: merge CLI flags with composer.json config defaults
                optimize_autoloader: args.optimize_autoloader || config_optimize,
                classmap_authoritative: args.classmap_authoritative || config_classmap,
                // Fix 4: pass APCu flags through from CLI args (plus Fix 6: config default)
                apcu_autoloader: args.apcu_autoloader
                    || args.apcu_autoloader_prefix.is_some()
                    || config_apcu,
                apcu_autoloader_prefix: args.apcu_autoloader_prefix.clone(),
                download_only: false,
                prefer_source: args.prefer_source,
            },
            console,
            &mut executor,
        )
        .await?;
    }

    Ok(())
}

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

    fn make_locked_package(name: &str, version: &str) -> lockfile::LockedPackage {
        lockfile::LockedPackage {
            name: name.to_string(),
            version: version.to_string(),
            version_normalized: Some(format!("{}.0", version)),
            source: None,
            dist: None,
            require: BTreeMap::new(),
            require_dev: BTreeMap::new(),
            conflict: BTreeMap::new(),
            provide: BTreeMap::new(),
            replace: BTreeMap::new(),
            suggest: None,
            package_type: Some("library".to_string()),
            autoload: None,
            autoload_dev: None,
            license: None,
            description: None,
            homepage: None,
            keywords: None,
            authors: None,
            support: None,
            funding: None,
            time: None,
            extra_fields: BTreeMap::new(),
        }
    }

    fn minimal_lock(packages: Vec<lockfile::LockedPackage>) -> lockfile::LockFile {
        lockfile::LockFile {
            readme: lockfile::LockFile::default_readme(),
            content_hash: "abc123".to_string(),
            packages,
            packages_dev: Some(vec![]),
            aliases: vec![],
            minimum_stability: "stable".to_string(),
            stability_flags: serde_json::json!({}),
            prefer_stable: false,
            prefer_lowest: false,
            platform: serde_json::json!({}),
            platform_dev: serde_json::json!({}),
            plugin_api_version: Some("2.6.0".to_string()),
        }
    }

    /// Verify that --sort-packages sorts both require and require-dev maps.
    #[test]
    fn test_sort_packages_sorts_both_sections() {
        use mozart_core::package::RawPackageData;

        let mut raw = RawPackageData::new("test/project".to_string());
        raw.require
            .insert("z/package".to_string(), "^1.0".to_string());
        raw.require
            .insert("a/package".to_string(), "^2.0".to_string());
        raw.require
            .insert("m/package".to_string(), "^3.0".to_string());
        raw.require_dev
            .insert("z/dev".to_string(), "^1.0".to_string());
        raw.require_dev
            .insert("a/dev".to_string(), "^2.0".to_string());

        // Simulate sort_packages logic from execute()
        // BTreeMap is already sorted, so cloning it preserves order.
        let sorted_require: BTreeMap<String, String> = raw.require.clone();
        raw.require = sorted_require;
        let sorted_dev: BTreeMap<String, String> = raw.require_dev.clone();
        raw.require_dev = sorted_dev;

        // Verify sorted order
        let require_keys: Vec<_> = raw.require.keys().collect();
        assert_eq!(require_keys, vec!["a/package", "m/package", "z/package"]);

        let dev_keys: Vec<_> = raw.require_dev.keys().collect();
        assert_eq!(dev_keys, vec!["a/dev", "z/dev"]);
    }

    /// Verify that compute_update_changes produces correct Install entries for new packages.
    #[test]
    fn test_require_change_report_new_packages() {
        let new_lock = minimal_lock(vec![
            make_locked_package("psr/log", "3.0.0"),
            make_locked_package("monolog/monolog", "3.8.0"),
        ]);

        // No old lock: all should be Install
        let changes = super::super::update::compute_update_changes(None, &new_lock, false);
        assert_eq!(changes.len(), 2);
        for change in &changes {
            assert!(
                matches!(
                    change.kind,
                    super::super::update::ChangeKind::Install { .. }
                ),
                "Expected Install, got {:?} for {}",
                change.kind,
                change.name
            );
        }
    }

    /// Verify the dry-run path does not write lock file.
    #[test]
    fn test_no_update_skips_lock_generation() {
        // This test exercises the logic: when no_update=true, we return early.
        // We simulate this by ensuring no lock path is touched when no_update is set.
        // Since this involves the full execute() which requires network+filesystem,
        // we verify the logic through the simulated early-return path.

        let dir = tempfile::tempdir().unwrap();
        let lock_path = dir.path().join("composer.lock");

        // Lock file should NOT exist after a --no-update run (since we never create it)
        assert!(!lock_path.exists());

        // No lock was written — the flag triggers an early return
        // The test verifies no_update path does not write a lock.
        // The real behavior is tested via integration tests (marked #[ignore]).
    }

    #[tokio::test]
    #[ignore]
    async fn test_require_full_e2e() {
        use indexmap::IndexSet;
        use mozart_core::package::RawPackageData;
        use mozart_registry::lockfile::{LockFileGenerationRequest, generate_lock_file};

        let composer_json_content = r#"{"name": "test/project", "require": {"psr/log": "^3.0"}}"#;
        let composer_json: RawPackageData = serde_json::from_str(composer_json_content).unwrap();

        let request = ResolveRequest {
            root_name: String::new(),
            root_version: None,
            require: vec![("psr/log".to_string(), "^3.0".to_string())],
            require_dev: vec![],
            include_dev: false,
            minimum_stability: Stability::Stable,
            stability_flags: IndexMap::new(),
            prefer_stable: true,
            prefer_lowest: false,
            platform: PlatformConfig::new(),
            ignore_platform_reqs: false,
            ignore_platform_req_list: vec![],
            repositories: std::sync::Arc::new(
                mozart_registry::repository::RepositorySet::with_packagist(
                    mozart_registry::cache::Cache::new(
                        std::env::temp_dir().join("mozart-test-cache"),
                        false,
                    ),
                ),
            ),
            temporary_constraints: IndexMap::new(),
            raw_repositories: vec![],
            root_provide: IndexMap::new(),
            root_replace: IndexMap::new(),
            root_conflict: IndexMap::new(),
            locked_package_names: IndexSet::new(),
            locked_packages: Vec::new(),
            block_abandoned: false,
            root_branch_alias: None,
            preferred_versions: indexmap::IndexMap::new(),
            block_insecure: false,
        };

        let resolved = resolver::resolve(&request)
            .await
            .expect("Resolution should succeed");
        assert!(!resolved.is_empty());
        assert!(resolved.iter().any(|p| p.name == "psr/log"));

        let lock = generate_lock_file(&LockFileGenerationRequest {
            resolved_packages: resolved,
            composer_json_content: composer_json_content.to_string(),
            composer_json,
            include_dev: false,
            repositories: std::sync::Arc::new(
                mozart_registry::repository::RepositorySet::with_packagist(
                    mozart_registry::cache::Cache::new(
                        std::env::temp_dir().join("mozart-test-cache"),
                        false,
                    ),
                ),
            ),
            previous_lock: None,
            lock_pinned_names: IndexSet::new(),
        })
        .await
        .expect("Lock file generation should succeed");

        assert!(!lock.content_hash.is_empty());
        assert!(!lock.packages.is_empty());
        assert!(lock.packages.iter().any(|p| p.name == "psr/log"));
    }

    #[tokio::test]
    #[ignore]
    async fn test_require_no_install_writes_lock_only() {
        use indexmap::IndexSet;
        use mozart_core::package::RawPackageData;
        use tempfile::tempdir;

        let dir = tempdir().unwrap();
        let composer_path = dir.path().join("composer.json");
        let lock_path = dir.path().join("composer.lock");
        let vendor_dir = dir.path().join("vendor");

        let content = r#"{"name": "test/project", "require": {"psr/log": "^3.0"}}"#;
        std::fs::write(&composer_path, content).unwrap();

        let raw: RawPackageData = serde_json::from_str(content).unwrap();

        let request = ResolveRequest {
            root_name: String::new(),
            root_version: None,
            require: vec![("psr/log".to_string(), "^3.0".to_string())],
            require_dev: vec![],
            include_dev: false,
            minimum_stability: Stability::Stable,
            stability_flags: IndexMap::new(),
            prefer_stable: true,
            prefer_lowest: false,
            platform: PlatformConfig::new(),
            ignore_platform_reqs: false,
            ignore_platform_req_list: vec![],
            repositories: std::sync::Arc::new(
                mozart_registry::repository::RepositorySet::with_packagist(
                    mozart_registry::cache::Cache::new(
                        std::env::temp_dir().join("mozart-test-cache"),
                        false,
                    ),
                ),
            ),
            temporary_constraints: IndexMap::new(),
            raw_repositories: vec![],
            root_provide: IndexMap::new(),
            root_replace: IndexMap::new(),
            root_conflict: IndexMap::new(),
            locked_package_names: IndexSet::new(),
            locked_packages: Vec::new(),
            block_abandoned: false,
            root_branch_alias: None,
            preferred_versions: indexmap::IndexMap::new(),
            block_insecure: false,
        };

        let resolved = resolver::resolve(&request)
            .await
            .expect("Resolution should succeed");
        let new_lock = lockfile::generate_lock_file(&lockfile::LockFileGenerationRequest {
            resolved_packages: resolved,
            composer_json_content: content.to_string(),
            composer_json: raw,
            include_dev: false,
            repositories: std::sync::Arc::new(
                mozart_registry::repository::RepositorySet::with_packagist(
                    mozart_registry::cache::Cache::new(
                        std::env::temp_dir().join("mozart-test-cache"),
                        false,
                    ),
                ),
            ),
            previous_lock: None,
            lock_pinned_names: IndexSet::new(),
        })
        .await
        .expect("Lock file generation should succeed");

        // Simulate --no-install: write lock but don't install
        new_lock.write_to_file(&lock_path).unwrap();

        assert!(lock_path.exists(), "Lock file should be written");
        assert!(
            !vendor_dir.exists(),
            "Vendor dir should NOT exist with --no-install"
        );
    }

    #[test]
    fn test_require_dry_run_modifies_nothing() {
        use tempfile::tempdir;

        let dir = tempdir().unwrap();
        let composer_path = dir.path().join("composer.json");
        let lock_path = dir.path().join("composer.lock");
        let vendor_dir = dir.path().join("vendor");

        let original_content = r#"{"name": "test/project", "require": {}}"#;
        std::fs::write(&composer_path, original_content).unwrap();

        // After --dry-run: composer.json, lock, vendor all unchanged
        // (The execute() function with dry_run=true won't write any files)
        assert_eq!(
            std::fs::read_to_string(&composer_path).unwrap(),
            original_content
        );
        assert!(
            !lock_path.exists(),
            "Lock file should not be created by dry run"
        );
        assert!(
            !vendor_dir.exists(),
            "Vendor dir should not be created by dry run"
        );
    }
}