#include "include/memory.h"
#include "include/errors.h"
#include "include/utils.h"
#include "include/types.h"
using namespace std;

Memory::Memory(void) {
    scopes.emplace_back();
    scopes.back().depth = 0;
}

bool Memory::contains(string identifier) {
    for (auto rit = scopes.rbegin(); rit != scopes.rend(); ++rit) {
        Scope& scope = *rit;
        if (scope.vars.contains(identifier)) return true;
        if (scope.type == ScopeType::Function) {
            Closure closure = std::get<1>(std::get<Function>(scope.fn->value));
            if (closure.contains(identifier)) return true;
            break;
        }
    }
    
    return false;
}

bool Memory::contains_top(string identifier) {
    Scope& top = scopes.back();
    return top.vars.contains(identifier);
}

void Memory::add_scope(ScopeType type, MemoryVar* fn, CodePosition entry_pos) {
    Scope& top = scopes.back();
    Scope& newScope = scopes.emplace_back();
    newScope.depth = top.depth + 1;
    newScope.type = type;
    newScope.fn = fn;
    newScope.entry_pos = entry_pos;
}

void Memory::remove_scope(void) {
    scopes.pop_back();
}

MemoryVar& Memory::get(string identifier) {
    for (auto rit = scopes.rbegin(); rit != scopes.rend(); ++rit) {
        Scope& scope = *rit;
        if (scope.vars.contains(identifier)) return scope.vars[identifier];
        if (scope.type == ScopeType::Function) {
            Closure closure = std::get<1>(std::get<Function>(scope.fn->value));
            if (closure.contains(identifier)) return closure.at(identifier);
            break;
        }
    }
    
    throw exception();
}

Scope& Memory::get_function_scope(void) {
    for (auto rit = scopes.rbegin(); rit != scopes.rend(); ++rit) {
        Scope& scope = *rit;
        if (scope.type == ScopeType::Function) return scope;
    }
    
    // Tmp: no flow control
    throw InternalError();
}

void Memory::declare(string identifier, Type type) {
    Scope& top = scopes.back();
    top.vars[identifier].type = type;
    top.vars[identifier].identifier = identifier;
}

void Memory::update(string identifier, EvalResult value) {
    for (auto rit = scopes.rbegin(); rit != scopes.rend(); ++rit) {
        Scope& scope = *rit;
        if (scope.vars.contains(identifier)) {
            scope.vars[identifier].value = value;
            scope.vars[identifier].initialized = true;
            return;
        }
        if (scope.type == ScopeType::Function) {
            Closure closure = std::get<1>(std::get<Function>(scope.fn->value));
            if (closure.contains(identifier)) {
                MemoryVar& var = closure.at(identifier);
                var.value = value;
                var.initialized = true;
            }
        }
    }
    
    throw exception();
}

Closure Memory::make_closure(void) {
    Closure closure;
    
    for (auto rit = scopes.rbegin(); rit != scopes.rend(); ++rit) {
        Scope& scope = *rit;
        for (auto& [identifier, var] : scope.vars) {
            if (!closure.contains(identifier)) closure.insert_or_assign(identifier, var);
        }
    }

    return closure;
}

StackTrace Memory::get_trace(CodePosition pos) {
    StackTrace trace = {};

    for (auto rit = scopes.rbegin(); rit != scopes.rend(); ++rit) {
        Scope& scope = *rit;
        if (scope.type == ScopeType::Function) {
            StackTraceEntry entry = { scope.fn->identifier, pos };
            trace.push_back(entry);
            pos = scope.entry_pos;
        }
    }

    StackTraceEntry top = { "<repl>", pos };
    trace.push_back(top);

    return trace;
}

Scope& Memory::_debug_top(void) {
    Scope& top = scopes.back();
    return top;
}

void _debug_print_memory_var(MemoryVar var) {
    if (var.initialized && !holds_alternative<monostate>(var.value)) {
        cout << " ";
        if (holds_alternative<int>(var.value)) {
            cout << get<int>(var.value);
        } else if (holds_alternative<double>(var.value)) {
            cout << get<double>(var.value);
        } else {
            cout << "{Unsupported}";
        }
    } else {
        cout << setw (5) << "{}";
    }
}

void _debug_print_scope(Scope scope) {
    for (auto it : scope.vars) {
        if (it.first.length() > 6) {
            cout << it.first.substr(0, 6) << "..";
        } else {
            cout << setw (6) << it.first << "  ";
        }
        cout << "|";
        cout << setw (7) << _debug_get_type_type_name(it.second.type.type) << " |";
        
        _debug_print_memory_var(it.second);
        cout << endl;
    }
}

void Memory::_debug_print(void) {
    cout << BOLD "  Name  |  Type  |  Value" RESET << endl;
    for (auto rit = scopes.rbegin(); rit != scopes.rend(); ++rit) {
        Scope& scope = *rit;
        if (rit != scopes.rbegin()) {
            cout << "   ---  New Scope  ---" << endl;
        }

        _debug_print_scope(scope);
    }
}