#include "lumacs/keybinding.hpp"
#include <sstream>
#include <algorithm>
#include <cctype>

namespace lumacs {

// ============================================================================
// Key Implementation
// ============================================================================

Key::Key(const std::string& key_name) {
    *this = parse(key_name);
}

Key Key::parse(const std::string& key_str) {
    Key key;
    
    if (key_str.empty()) {
        return key;
    }
    
    std::string remaining = key_str;
    
    // Parse modifiers
    while (true) {
        if (remaining.length() >= 2 && remaining.substr(0, 2) == "C-") {
            key.ctrl = true;
            remaining = remaining.substr(2);
        } else if (remaining.length() >= 2 && (remaining.substr(0, 2) == "M-" || remaining.substr(0, 2) == "A-")) {
            key.meta = true;
            remaining = remaining.substr(2);
        } else if (remaining.length() >= 2 && remaining.substr(0, 2) == "S-") {
            key.shift = true;
            remaining = remaining.substr(2);
        } else {
            break;
        }
    }
    
    // The rest is the key name
    key.name = remaining;
    
    return key;
}

std::string Key::to_string() const {
    std::string result;
    
    if (ctrl) result += "C-";
    if (meta) result += "M-";
    if (shift) result += "S-";
    
    result += name;
    
    return result;
}

bool Key::operator==(const Key& other) const {
    return name == other.name && 
           ctrl == other.ctrl && 
           meta == other.meta && 
           shift == other.shift;
}

bool Key::operator<(const Key& other) const {
    if (name != other.name) return name < other.name;
    if (ctrl != other.ctrl) return ctrl < other.ctrl;
    if (meta != other.meta) return meta < other.meta;
    return shift < other.shift;
}

// ============================================================================
// KeySequence Implementation
// ============================================================================

KeySequence::KeySequence(const std::vector<Key>& keys) : keys_(keys) {
}

KeySequence::KeySequence(const std::string& key_sequence_str) {
    if (key_sequence_str.empty()) {
        return;
    }
    
    // Split by spaces, but handle quoted strings
    std::istringstream iss(key_sequence_str);
    std::string token;
    
    while (iss >> token) {
        keys_.emplace_back(Key::parse(token));
    }
}

void KeySequence::add_key(const Key& key) {
    keys_.push_back(key);
}

void KeySequence::add_key(const std::string& key_str) {
    keys_.emplace_back(Key::parse(key_str));
}

bool KeySequence::is_prefix_of(const KeySequence& other) const {
    if (keys_.size() > other.keys_.size()) {
        return false;
    }
    
    return std::equal(keys_.begin(), keys_.end(), other.keys_.begin());
}

bool KeySequence::has_prefix(const KeySequence& prefix) const {
    return prefix.is_prefix_of(*this);
}

std::string KeySequence::to_string() const {
    if (keys_.empty()) {
        return "";
    }
    
    std::string result = keys_[0].to_string();
    
    for (size_t i = 1; i < keys_.size(); ++i) {
        result += " " + keys_[i].to_string();
    }
    
    return result;
}

void KeySequence::clear() {
    keys_.clear();
}

KeySequence KeySequence::subsequence(size_t start_index) const {
    if (start_index >= keys_.size()) {
        return KeySequence();
    }
    
    std::vector<Key> sub_keys(keys_.begin() + start_index, keys_.end());
    return KeySequence(sub_keys);
}

bool KeySequence::operator==(const KeySequence& other) const {
    return keys_ == other.keys_;
}

bool KeySequence::operator<(const KeySequence& other) const {
    return keys_ < other.keys_;
}

// ============================================================================
// KeyBinding Implementation
// ============================================================================

KeyBinding::KeyBinding(const KeySequence& seq, KeyBindingFunction func, std::string desc)
    : sequence(seq), function(std::move(func)), description(std::move(desc)) {
}

KeyBinding::KeyBinding(const std::string& key_str, KeyBindingFunction func, std::string desc)
    : sequence(key_str), function(std::move(func)), description(std::move(desc)) {
}

// ============================================================================
// KeyBindingManager Implementation
// ============================================================================

KeyBindingManager::KeyBindingManager() 
    : sequence_timeout_(std::chrono::milliseconds(1000)) {
}

void KeyBindingManager::bind(const KeySequence& sequence, KeyBindingFunction function, const std::string& description) {
    if (sequence.empty() || !function) {
        return;
    }
    
    bindings_[sequence] = KeyBinding(sequence, std::move(function), description);
}

void KeyBindingManager::bind(const std::string& key_str, KeyBindingFunction function, const std::string& description) {
    bind(KeySequence(key_str), std::move(function), description);
}

void KeyBindingManager::unbind(const KeySequence& sequence) {
    bindings_.erase(sequence);
}

void KeyBindingManager::unbind(const std::string& key_str) {
    unbind(KeySequence(key_str));
}

KeyResult KeyBindingManager::process_key(const Key& key) {
    // Check for timeout first
    if (is_building_sequence() && has_sequence_timed_out()) {
        clear_partial_sequence();
        // Fall through to process this key as a new sequence
    }
    
    // Add this key to the current sequence
    current_sequence_.add_key(key);
    
    // Update timestamp
    sequence_start_time_ = std::chrono::steady_clock::now();
    
    // Check for exact binding
    auto exact_binding = find_exact_binding(current_sequence_);
    if (exact_binding.has_value()) {
        // Found exact match
        clear_partial_sequence();
        
        try {
            bool success = exact_binding->function();
            return success ? KeyResult::Executed : KeyResult::Failed;
        } catch (...) {
            return KeyResult::Failed;
        }
    }
    
    // Check if this could be a prefix for other bindings
    if (has_prefix_bindings_impl(current_sequence_)) {
        return KeyResult::Partial;
    }
    
    // No binding found, clear sequence and return unbound
    clear_partial_sequence();
    return KeyResult::Unbound;
}

KeyResult KeyBindingManager::process_key(const std::string& key_str) {
    return process_key(Key::parse(key_str));
}

bool KeyBindingManager::has_binding(const KeySequence& sequence) const {
    return has_exact_binding(sequence) || has_prefix_bindings(sequence);
}

bool KeyBindingManager::has_exact_binding(const KeySequence& sequence) const {
    return bindings_.find(sequence) != bindings_.end();
}

bool KeyBindingManager::has_prefix_bindings(const KeySequence& sequence) const {
    return has_prefix_bindings_impl(sequence);
}

void KeyBindingManager::clear_partial_sequence() {
    current_sequence_.clear();
    sequence_start_time_ = std::chrono::steady_clock::time_point{};
}

bool KeyBindingManager::is_building_sequence() const {
    return !current_sequence_.empty();
}

std::string KeyBindingManager::current_sequence_display() const {
    if (current_sequence_.empty()) {
        return "";
    }
    
    return current_sequence_.to_string() + "-";
}

std::vector<KeyBinding> KeyBindingManager::get_all_bindings() const {
    std::vector<KeyBinding> result;
    result.reserve(bindings_.size());
    
    for (const auto& [sequence, binding] : bindings_) {
        result.push_back(binding);
    }
    
    return result;
}

void KeyBindingManager::set_sequence_timeout(std::chrono::milliseconds timeout) {
    sequence_timeout_ = timeout;
}

bool KeyBindingManager::has_sequence_timed_out() const {
    if (!is_building_sequence()) {
        return false;
    }
    
    auto now = std::chrono::steady_clock::now();
    return (now - sequence_start_time_) > sequence_timeout_;
}

std::optional<KeyBinding> KeyBindingManager::find_exact_binding(const KeySequence& sequence) const {
    auto it = bindings_.find(sequence);
    if (it != bindings_.end()) {
        return it->second;
    }
    return std::nullopt;
}

bool KeyBindingManager::has_prefix_bindings_impl(const KeySequence& sequence) const {
    // Check if any registered binding has this sequence as a prefix
    for (const auto& [binding_sequence, binding] : bindings_) {
        if (sequence.is_prefix_of(binding_sequence) && sequence != binding_sequence) {
            return true;
        }
    }
    return false;
}

} // namespace lumacs