var shop = use('internal/shop')
var pkg = use('package')

if (!args || length(args) < 1) {
    log.console("Usage: cell why <package>")
    $stop()
    return
}

var target = args[0]
log.console("Searching for '" + target + "'...")

var target_clean = target
if (starts_with(target_clean, '/')) target_clean = text(target_clean, 1)

var found = false

// DFS to find paths
// current_pkg: canonical path of current package (null for root)
// stack: array of {alias, pkg} leading to current_pkg

function search(current_pkg, stack) {
    var deps = pkg.dependencies(current_pkg)
    
    // Sort for consistent output
    var aliases = sort(array(deps))
    
    for (var i = 0; i < length(aliases); i++) {
        var alias = aliases[i]
        var locator = deps[alias]
        var parsed = shop.parse_package(locator)
        if (!parsed) continue
        
        var canon = parsed.path
        
        var locator_clean = locator
        if (search(locator, '@') != null) locator_clean = array(locator, '@')[0]
        
        // Check if match
        // 1. Alias matches
        // 2. Package name matches
        // 3. Canonical path matches (exact or clean)
        // 4. Locator matches (exact or clean)
        var match = (alias == target) || 
                    (parsed.name == target) || 
                    (canon == target) || 
                    (canon == target_clean) ||
                    (locator == target) ||
                    (locator_clean == target)
        
        var node = { alias: alias, pkg: canon, locator: locator }
        var new_stack = stack.concat([node])
        
        if (match) {
            found = true
            print_stack(new_stack)
            // Don't recurse if we found the target in this branch
            continue 
        }
        
        // Recurse if not seen in current stack (cycle detection)
        var cycle = false
        for (var j = 0; j < length(stack); j++) {
            if (stack[j].pkg == canon) {
                cycle = true
                break
            }
        }
        
        if (!cycle) {
            search(canon, new_stack)
        }
    }
}

function print_stack(stack) {
    // Calculate max width for alignment if needed, but simple tree is fine
    var output = "project"
    log.console(output)
    
    for (var i = 0; i < length(stack); i++) {
        var node = stack[i]
        var indent = ""
        for (var j = 0; j <= i; j++) indent += "  "
        
        var info = node.locator
        if (node.alias != parsed_name(node.locator)) {
             // info += " (aliased as " + node.alias + ")"
        }
        
        log.console(indent + "-> " + node.alias + " (" + info + ")")
    }
    log.console("")
}

function parsed_name(locator) {
    var parsed = shop.parse_package(locator)
    return parsed ? parsed.name : ""
}

search(null, [])

if (!found) {
    log.console("Package '" + target + "' not found in dependency tree.")
}

$stop()