/******************************************************************************
               __               ____                __
              / /   ___  ____ _/ __/_____________ _/ /__
             / /   / _ \/ __ `/ /_/ ___/ ___/ __ `/ / _ \
            / /___/  __/ /_/ / __(__  ) /__/ /_/ / /  __/
           /_____/\___/\__,_/_/ /____/\___/\__,_/_/\___/

   (C)opyright 2025, Leafscale, LLC -  https://www.leafscale.com

   Project: Zygaena
  Filename: remove.reef
   Authors: Chris Tusa <chris.tusa@leafscale.com>
   License: <see LICENSE file included with this source code>
Description: Remove command - uninstall packages

******************************************************************************/

module commands.remove

import sys.args
import sys.process
import io.file
import io.dir
import io.path
import core.str
import core.config
import core.database
import core.pkgdb
import core.package
import core.port
import util.prompt
import util.mtree
import util.checksum
import types
import util.color
import fs.stat
import fs.ops
import util.priv
import exitcodes as ec
import core.result as res

export
    fn execute(opts: types.GlobalOptions): int
end export

fn execute(opts: types.GlobalOptions): int
    let argc = args.count()

    // Package arguments should be after the command
    if argc <= opts.cmd_index + 1
        print_usage()
        return ec.EXIT_USAGE()
    end if

    // Load configuration and apply command-line overrides
    let base_cfg = config.load()
    let cfg = config.apply_overrides(base_cfg, opts.root, opts.prefix, opts.no_chroot)
    let root_path = config.get_root(cfg)

    // Show root if set (verbose mode)
    if opts.verbose and str.length(root_path) > 0
        color.print_info("Using root: " + root_path)
    end if

    // Collect packages to remove
    mut packages: [string] = new [string](256)
    mut pkg_count = 0

    mut i = opts.cmd_index + 1
    while i < argc and pkg_count < 256
        let pkg_name = args.get(i)

        // Skip flags and their values
        if pkg_name == "--root" or pkg_name == "--prefix"
            i = i + 2  // Skip flag and its value
            continue
        elif pkg_name == "--no-chroot-scripts"
            i = i + 1  // valueless flag: skip only itself
            continue
        end if
        if str.starts_with(pkg_name, "-")
            i = i + 1
            continue
        end if

        // Check if installed (use rooted version if root is set)
        let installed = check_installed(pkg_name, root_path)
        if installed
            packages[pkg_count] = pkg_name
            pkg_count = pkg_count + 1
        else
            color.print_warning(pkg_name + " is not installed")
        end if

        i = i + 1
    end while

    if pkg_count == 0
        color.print_info("No packages to remove")
        return ec.EXIT_SUCCESS()
    end if

    // Check for reverse dependencies (packages that depend on these)
    mut dependents: [string] = new [string](256)
    mut dependent_count = 0

    i = 0
    while i < pkg_count
        let pkg_name = packages[i]
        let count = get_reverse_dependencies(pkg_name, dependents, dependent_count, 256)
        dependent_count = count
        i = i + 1
    end while

    // Warn if there are dependents
    if dependent_count > 0
        color.print_warning("The following installed packages depend on packages being removed:")
        i = 0
        while i < dependent_count
            println("  - " + dependents[i])
            i = i + 1
        end while

        // Require --force to proceed
        if not opts.force
            color.print_error("Use --force to remove packages with dependents")
            return ec.EXIT_DEPS_CONFLICT()
        end if
        color.print_warning("Proceeding with removal (--force specified)")
    end if

    // Ask for confirmation (unless -y flag)
    if not prompt.confirm_remove(packages, pkg_count, dependents, dependent_count, opts)
        color.print_info("Removal cancelled")
        return ec.EXIT_CANCELLED()
    end if

    // Dry-run: show what would be done and exit
    if opts.dry_run
        color.print_info("Dry run — no changes made")
        return ec.EXIT_SUCCESS()
    end if

    // Remove packages
    mut all_success = true
    i = 0
    while i < pkg_count
        if not remove_package(packages[i], root_path, cfg)
            color.print_error("Failed to remove: " + packages[i])
            all_success = false
        end if
        i = i + 1
    end while

    if all_success
        return ec.EXIT_SUCCESS()
    else
        return ec.EXIT_REMOVE_FAILED()
    end if
end execute

// Check if package is installed, using rooted check if root is set
fn check_installed(name: string, root_path: string): bool
    if str.length(root_path) > 0
        return database.is_installed_rooted(name, root_path)
    end if
    return database.is_installed(name)
end check_installed

proc print_usage()
    println("Usage: coral remove <package...>")
    println("")
    println("Remove one or more installed packages.")
    println("")
    println("Arguments:")
    println("  <package>    Name of installed package to remove")
    println("")
    println("Options:")
    println("  -y, --yes    Don't ask for confirmation")
    println("  -f, --force  Remove even if other packages depend on it")
    println("")
    println("Examples:")
    println("  coral remove vim")
    println("  coral remove vim nano htop")
    println("  coral remove --force libfoo")
end print_usage

fn remove_package(pkg_name: string, root_path: string, cfg: config.Config): bool
    // Check if package is installed (use rooted version if root is set)
    if not check_installed(pkg_name, root_path)
        color.print_error(pkg_name + " is not installed")
        return false
    end if

    color.print_action("Removing " + pkg_name + "...")

    let install_root = get_actual_root(root_path)
    // Resolve script execution context; abort early if confinement is required but impossible.
    // Defense-in-depth: main.reef already bars non-root for all non-query commands, so this abort
    // is currently unreachable via the CLI. Kept so confinement fails safely if that global gate is
    // ever relaxed.
    if package.script_wants_chroot(install_root, config.get_chroot_scripts(cfg)) and not priv.is_root()
        color.print_error("--root " + install_root + " runs maintainer scripts confined to the target via chroot, which requires root privileges.")
        color.print_error("Re-run as root, or pass --no-chroot-scripts to run them on the host (unconfined).")
        return false
    end if
    let script_ctx = package.resolve_script_ctx(install_root, config.get_chroot_scripts(cfg), priv.is_root())

    // Get package info (use rooted version if root is set)
    let pkg = get_installed_pkg(pkg_name, root_path)
    color.print_info("Package: " + pkg.info.name + " " + pkg.info.version)

    // Get file list from database (use rooted version if root is set)
    mut files: [string] = new [string](4096)
    let file_count = get_files_list(pkg_name, files, 4096, root_path)

    if file_count == 0
        color.print_warning("No files recorded for package")
    else
        color.print_info("Removing " + int_to_str(file_count) + " files...")
    end if

    // Run pre-remove script if present (abort on failure)
    let scripts_dir = database.get_scripts_dir(pkg_name)
    if database.has_stored_scripts(pkg_name)
        color.print_info("Running pre-remove script...")
        if not package.run_stored_pre_remove(script_ctx, scripts_dir, pkg.info.version)
            color.print_error("Pre-remove script failed, aborting removal of " + pkg_name)
            return false
        end if
    end if

    // Load config file list and manifest checksums for config protection
    mut config_files: [string] = new [string](256)
    let config_count = database.get_config_files(pkg_name, config_files, 256)

    mut manifest_entries: [mtree.ManifestEntry] = new [mtree.ManifestEntry](8192)
    mut manifest_count = 0
    let manifest_path = database.get_manifest_path(pkg_name)
    if file.fileExists(manifest_path)
        let manifest_content = res.unwrap_or(file.readFile(manifest_path), "")
        if str.length(manifest_content) > 0
            manifest_count = mtree.parse_manifest(manifest_content, manifest_entries, 8192)
        end if
    end if

    // Remove files (with proper root path, respecting config protection)
    let actual_root = get_actual_root(root_path)
    if not remove_files(files, file_count, actual_root, config_files, config_count, manifest_entries, manifest_count)
        color.print_warning("Some files could not be removed")
        // Continue anyway - unregister from database
    end if

    // Run post-remove script if present (warn on failure, don't abort)
    if database.has_stored_scripts(pkg_name)
        color.print_info("Running post-remove script...")
        if not package.run_stored_post_remove(script_ctx, scripts_dir, pkg.info.version)
            color.print_warning("Post-remove script failed")
        end if
    end if

    // Unregister from database (use rooted version if root is set)
    color.print_info("Unregistering package...")
    if not unregister_pkg(pkg_name, root_path)
        color.print_error("Failed to unregister package from database")
        return false
    end if

    // Update package database indexes
    if not pkgdb.rebuild_indexes_rooted(root_path)
        color.print_warning("Failed to update package indexes")
    end if

    color.print_success("Removed " + pkg_name)
    return true
end remove_package

// Get installed package info, using rooted check if root is set
fn get_installed_pkg(name: string, root_path: string): types.InstalledPackage
    if str.length(root_path) > 0
        return database.get_installed_rooted(name, root_path)
    end if
    return database.get_installed(name)
end get_installed_pkg

// Get files list, using rooted check if root is set
fn get_files_list(name: string, files: [string], max_count: int, root_path: string): int
    if str.length(root_path) > 0
        return database.get_files_rooted(name, files, max_count, root_path)
    end if
    return database.get_files(name, files, max_count)
end get_files_list

// Unregister package, using rooted version if root is set
fn unregister_pkg(name: string, root_path: string): bool
    if str.length(root_path) > 0
        return database.unregister_package_rooted(name, root_path)
    end if
    return database.unregister_package(name)
end unregister_pkg

// Get actual root path (returns "/" if empty)
fn get_actual_root(root_path: string): string
    if str.length(root_path) == 0
        return "/"
    end if
    return root_path
end get_actual_root

// Remove files from system, respecting config file protection
fn remove_files(files: [string], file_count: int, root_path: string, config_files: [string], config_count: int, manifest_entries: [mtree.ManifestEntry], manifest_count: int): bool
    mut all_success = true

    // Remove files in reverse order
    mut i = file_count - 1
    while i >= 0
        let rel_path = files[i]
        let full_path = path.join_path(root_path, rel_path)

        if stat.is_symlink(full_path) or stat.exists(full_path)
            // Check if this is a config file that the user has modified
            if config_count > 0 and package.is_config_file(rel_path, config_files, config_count)
                // Look up the package's sha256 from the manifest
                let pkg_sha = find_manifest_sha256(rel_path, manifest_entries, manifest_count)
                if str.length(pkg_sha) > 0
                    let installed_sha = checksum.sha256_file(full_path)
                    if not str.equals(installed_sha, pkg_sha)
                        // User has modified this config — preserve it
                        color.print_info("Preserving modified config: " + rel_path)
                        i = i - 1
                        continue
                    end if
                end if
            end if

            if not res.is_ok(ops.remove_file(full_path))
                color.print_warning("Failed to remove: " + full_path)
                all_success = false
            end if
        end if

        i = i - 1
    end while

    // Try to remove empty parent directories
    i = file_count - 1
    while i >= 0
        let rel_path = files[i]
        let full_path = path.join_path(root_path, rel_path)
        let parent = path.dirname(full_path)

        if str.length(parent) > str.length(root_path) and dir.dir_exists(parent)
            dir.remove_dir(parent)
        end if

        i = i - 1
    end while

    return all_success
end remove_files

// Look up the sha256 for a given relative path in the manifest entries
fn find_manifest_sha256(rel_path: string, entries: [mtree.ManifestEntry], count: int): string
    mut i = 0
    while i < count
        let epath = mtree.entry_path(entries[i])
        // Compare with and without ./ prefix
        mut entry_rel = epath
        if str.starts_with(epath, "./")
            entry_rel = str.substring(epath, 2, str.length(epath) - 2)
        end if
        if str.equals(entry_rel, rel_path)
            return mtree.entry_sha256(entries[i])
        end if
        i = i + 1
    end while
    return ""
end find_manifest_sha256

// Get packages that depend on the given package
// Returns new total count (existing + new dependents)
fn get_reverse_dependencies(pkg_name: string, dependents: [string], current_count: int, max_count: int): int
    mut count = current_count

    // List all installed packages
    mut installed: [string] = new [string](512)
    let installed_count = database.list_installed(installed, 512)

    mut i = 0
    while i < installed_count and count < max_count
        let other_pkg = installed[i]

        // Skip the package being removed and already listed dependents
        if str.equals(other_pkg, pkg_name)
            i = i + 1
            continue
        end if

        // Check if already in dependents list
        if array_contains(dependents, count, other_pkg)
            i = i + 1
            continue
        end if

        // Try to find this package's port to get its dependencies
        let port_result = port.find(other_pkg)
        if port_result.success
            let p = port_result.port

            // Check runtime dependencies
            if depends_on(p.deps.runtime, p.deps.runtime_count, pkg_name)
                dependents[count] = other_pkg
                count = count + 1
            end if
        end if

        i = i + 1
    end while

    return count
end get_reverse_dependencies

// Check if a dependency list contains the given package
fn depends_on(deps: [string], dep_count: int, pkg_name: string): bool
    mut i = 0
    while i < dep_count
        let dep = deps[i]

        // Handle alternative dependencies (format: base:opt1,opt2)
        let colon_pos = str.index_of_char(dep, ':')
        mut base_dep = dep
        if colon_pos > 0
            base_dep = str.substring(dep, 0, colon_pos)
        end if

        if str.equals(base_dep, pkg_name)
            return true
        end if

        i = i + 1
    end while

    return false
end depends_on

// Helper to check if array contains a string
fn array_contains(arr: [string], count: int, s: string): bool
    mut i = 0
    while i < count
        if str.equals(arr[i], s)
            return true
        end if
        i = i + 1
    end while
    return false
end array_contains

// Helper: convert int to string
fn int_to_str(n: int): string
    if n == 0
        return "0"
    end if

    mut negative = false
    mut value = n
    if n < 0
        negative = true
        value = 0 - n
    end if

    mut result = ""
    while value > 0
        let digit = value % 10
        result = str.concat(str.substring("0123456789", digit, 1), result)
        value = value / 10
    end while

    if negative
        result = str.concat("-", result)
    end if

    return result
end int_to_str

end module