#include "interpreter.h"
#include "parser.h"
#include "types.h"
#include "include/uthash.h"
#include <stdlib.h>
#include <string.h>

int currentInstruction = 0;

void runtimeError(GroundRuntimeError error, char* what, GroundInstruction* where, int whereLine) {
    printf("Ground runtime error:\n  ErrorType: ");
    switch (error) {
        case ARG_TYPE_MISMATCH: {
            printf("ArgTypeMismatch");
            break;
        }
        case TOO_FEW_ARGS: {
            printf("TooFewArgs");
            break;
        }
        case TOO_MANY_ARGS: {
            printf("TooManyArgs");
            break;
        }
        case UNKNOWN_LABEL: {
            printf("UnknownLabel");
            break;
        }
        case UNKNOWN_VARIABLE: {
            printf("UnknownVariable");
            break;
        }
        default:
        case FIXME: {
            printf("FIXME (please report issue to https://chsp.au/ground/cground)");
        }
    }
    printf("\n");
    if (what != NULL) {
        printf("  ErrorContext: %s\n", what);
    }
    if (where != NULL) {
        printf("  ErrorInstruction: ");
        printGroundInstruction(where);
        printf("\n");
    }
    if (whereLine > -1) {
        printf("  ErrorLine: %d\n", whereLine + 1);
    }
    exit(1);
}

GroundLabel* findLabel(GroundLabel* head, const char *id) {
    GroundLabel *item;
    HASH_FIND_STR(head, id, item);
    return item;
}

void deleteLabel(GroundLabel** head, GroundLabel *item) {
    HASH_DEL(*head, item);
    free(item);
}

void addLabel(GroundLabel **head, const char *id, int data) {
    GroundLabel* label = findLabel(*head, id);
    if (label) {
        deleteLabel(head, label);
    }
    GroundLabel* item = malloc(sizeof(GroundLabel));
    snprintf(item->id, MAX_ID_LEN, "%s", id);
    item->lineNum = data;
    HASH_ADD_STR(*head, id, item);
}

GroundVariable* findVariable(GroundVariable* head, const char *id) {
    GroundVariable *item;
    HASH_FIND_STR(head, id, item);
    return item;
}

void deleteVariable(GroundVariable** head, GroundVariable *item) {
    HASH_DEL(*head, item);
    free(item);
}

void addVariable(GroundVariable **head, const char *id, GroundValue data) {
    GroundVariable* variable = findVariable(*head, id);
    if (variable) {
        deleteVariable(head, variable);
    }
    GroundVariable* item = malloc(sizeof(GroundVariable));
    snprintf(item->id, MAX_ID_LEN, "%s", id);
    item->value = data;
    HASH_ADD_STR(*head, id, item);
}

void interpretGroundProgram(GroundProgram* in) {
    GroundLabel* labels = NULL;
    GroundVariable* variables = NULL;

    GroundScope scope;
    scope.labels = &labels;
    scope.variables = &variables;
    // Preprocess all labels
    for (int i = 0; i < in->size; i++) {
        if (in->instructions[i].type == CREATELABEL) {
            addLabel(scope.labels, in->instructions[i].args.args[0].value.refName, i);
        }
    }
    while (currentInstruction < in->size) {
        interpretGroundInstruction(in->instructions[currentInstruction], &scope);
        currentInstruction++;
    }
    
}

void interpretGroundInstruction(GroundInstruction inst, GroundScope* scope) {
    GroundInstruction copied_inst = copyGroundInstruction(&inst);
    GroundInstruction* in = &copied_inst;

    // Insert variables prefixed with $
    for (int i = 0; i < in->args.length; i++) {
        if (in->args.args[i].type == VALREF) {
            GroundVariable* variable = findVariable(*scope->variables, in->args.args[i].value.refName);
            if (variable) {
                free(in->args.args[i].value.refName); // Free the strdup'd refName
                in->args.args[i].value.value = variable->value;
                in->args.args[i].type = VALUE;
            } else {
                runtimeError(UNKNOWN_VARIABLE, NULL, in, currentInstruction);
            }
        }
    }
    switch (in->type) {
        // We can safely ignore any CREATELABEL instructions, these have been preprocessed
        case CREATELABEL: {
            break;
        }
        case IF: {
            if (in->args.length < 2) {
                runtimeError(TOO_FEW_ARGS, "Expecting 2 arguments", in, currentInstruction);
            }
            if (in->args.length > 2) {
                runtimeError(TOO_MANY_ARGS, "Expecting 2 arguments", in, currentInstruction);
            }
            if (in->args.args[0].type != VALUE || in->args.args[0].value.value.type != BOOL) {
                runtimeError(ARG_TYPE_MISMATCH, "Expecting a bool for arg 0", in, currentInstruction);
            }
            if (in->args.args[1].type != LINEREF) {
                runtimeError(ARG_TYPE_MISMATCH, "Expecting a LineRef for arg 1", in, currentInstruction);
            }

            if (in->args.args[0].value.value.data.boolVal) {
                GroundLabel* label = findLabel(*scope->labels, in->args.args[1].value.refName);
                if (label) {
                    currentInstruction = label->lineNum;
                } else {
                    runtimeError(UNKNOWN_LABEL, NULL, in, currentInstruction);
                }
            }
            break;
        }
        case JUMP: {
            if (in->args.length < 1) {
                runtimeError(TOO_FEW_ARGS, "Expecting 1 argument", in, currentInstruction);
            }
            if (in->args.length > 1) {
                runtimeError(TOO_MANY_ARGS, "Expecting 1 argument", in, currentInstruction);
            }
            if (in->args.args[0].type != LINEREF) {
                runtimeError(ARG_TYPE_MISMATCH, "Expecting a LineRef for arg 1", in, currentInstruction);
            }

            GroundLabel* label = findLabel(*scope->labels, in->args.args[0].value.refName);
            if (label) {
                currentInstruction = label->lineNum;
            } else {
                runtimeError(UNKNOWN_LABEL, NULL, in, currentInstruction);
            }
            break;
        }
        case END: {
            if (in->args.length < 1 || in->args.args[0].type != VALUE || in->args.args[0].value.value.type != INT) {
                exit(0);
            } else {
                exit(in->args.args[0].value.value.data.intVal);
            }
            break;
        }
        case PRINT: {
            if (in->args.length < 1) {
                runtimeError(TOO_FEW_ARGS, "Expecting 1 or more args", in, currentInstruction);
            }
            for (int i = 0; i < in->args.length; i++) {
                if (i != 0) printf(" ");
                printGroundArg(&in->args.args[i]);
            }
            break;
        }
        case PRINTLN: {
            if (in->args.length < 1) {
                runtimeError(TOO_FEW_ARGS, "Expecting 1 or more args", in, currentInstruction);
            }
            for (int i = 0; i < in->args.length; i++) {
                if (i != 0) printf(" ");
                printGroundArg(&in->args.args[i]);
            }
            printf("\n");
            break;
        }
        case INPUT: {
            if (in->args.length < 1) {
                runtimeError(TOO_FEW_ARGS, "Expecting 1 arg", in, currentInstruction);
            }
            if (in->args.args[0].type != DIRREF) {
                runtimeError(ARG_TYPE_MISMATCH, "Expecting a DirectRef for arg 1", in, currentInstruction);
            }
            char buffer[256];
            if (fgets(buffer, sizeof(buffer), stdin) != NULL) {
                buffer[strcspn(buffer, "\n")] = '\0';
                addVariable(scope->variables, in->args.args[0].value.refName, createStringGroundValue(buffer));
            } else {
                runtimeError(FIXME, "Failed to read input from console with fgets", in, currentInstruction);
            }
            break;
        }

        case SET: {
            if (in->args.length < 2) {
                runtimeError(TOO_FEW_ARGS, "Expecting 2 args", in, currentInstruction);
            }
            if (in->args.length > 2) {
                runtimeError(TOO_MANY_ARGS, "Expecting 2 args", in, currentInstruction);
            }
            if (in->args.args[0].type != DIRREF) {
                runtimeError(ARG_TYPE_MISMATCH, "Expecting a DirectRef for arg 1", in, currentInstruction);
            }
            if (in->args.args[1].type != VALUE) {
                runtimeError(ARG_TYPE_MISMATCH, "Expecting a Value for arg 2", in, currentInstruction);
            }

            addVariable(scope->variables, in->args.args[0].value.refName, in->args.args[1].value.value);
            break;
        }

        case ADD: {
            if (in->args.length < 3) {
                runtimeError(TOO_FEW_ARGS, "Expecting 3 args", in, currentInstruction);
            }
            if (in->args.length > 3) {
                runtimeError(TOO_MANY_ARGS, "Expecting 3 args", in, currentInstruction);
            }
            if (in->args.args[0].type != VALUE) {
                runtimeError(ARG_TYPE_MISMATCH, "Expecting a Value for arg 1", in, currentInstruction);
            }
            if (in->args.args[1].type != VALUE) {
                runtimeError(ARG_TYPE_MISMATCH, "Expecting a Value for arg 2", in, currentInstruction);
            }
            if (in->args.args[2].type != DIRREF) {
                runtimeError(ARG_TYPE_MISMATCH, "Expecting a DirectRef for arg 3", in, currentInstruction);
            }

            GroundValue* left = &in->args.args[0].value.value;
            GroundValue* right = &in->args.args[1].value.value;

            if (left->type == STRING) {
                if (right->type != STRING) {
                    runtimeError(ARG_TYPE_MISMATCH, "Expecting a String for arg 2", in, currentInstruction);
                }
                char* newString = malloc(strlen(left->data.stringVal) + strlen(right->data.stringVal));
                strcpy(newString, left->data.stringVal);
                strcat(newString, right->data.stringVal);

                addVariable(scope->variables, in->args.args[2].value.refName, createStringGroundValue(newString));
            }
            else if (left->type == INT || left->type == DOUBLE) {
                if (right->type != INT && right->type != DOUBLE) {
                    runtimeError(ARG_TYPE_MISMATCH, "Expecting an Int or Double for arg 2", in, currentInstruction);
                }

                if (left->type == DOUBLE || right->type == DOUBLE) {
                    double result = 0;
                    
                    if (left->type == INT) {
                        result += left->data.intVal;
                    } else if (left->type == DOUBLE) {
                        result += left->data.doubleVal;
                    }
    
                    if (right->type == INT) {
                        result += right->data.intVal;
                    } else if (right->type == DOUBLE) {
                        result += right->data.doubleVal;
                    }

                    addVariable(scope->variables, in->args.args[2].value.refName, createDoubleGroundValue(result));
                } else {
                    int64_t result = left->data.intVal + right->data.intVal;
                    addVariable(scope->variables, in->args.args[2].value.refName, createIntGroundValue(result));
                }
            } else {
                runtimeError(ARG_TYPE_MISMATCH, "Expecting an Int, Double, or String for arg 1", in, currentInstruction);
            }
            break;
        }
        case SUBTRACT: {
            if (in->args.length < 3) {
                runtimeError(TOO_FEW_ARGS, "Expecting 3 args", in, currentInstruction);
            }
            if (in->args.length > 3) {
                runtimeError(TOO_MANY_ARGS, "Expecting 3 args", in, currentInstruction);
            }
            if (in->args.args[0].type != VALUE) {
                runtimeError(ARG_TYPE_MISMATCH, "Expecting a Value for arg 1", in, currentInstruction);
            }
            if (in->args.args[1].type != VALUE) {
                runtimeError(ARG_TYPE_MISMATCH, "Expecting a Value for arg 2", in, currentInstruction);
            }
            if (in->args.args[2].type != DIRREF) {
                runtimeError(ARG_TYPE_MISMATCH, "Expecting a DirectRef for arg 3", in, currentInstruction);
            }

            GroundValue* left = &in->args.args[0].value.value;
            GroundValue* right = &in->args.args[1].value.value;

            if (left->type == INT || left->type == DOUBLE) {
                if (right->type != INT && right->type != DOUBLE) {
                    runtimeError(ARG_TYPE_MISMATCH, "Expecting an Int or Double for arg 2", in, currentInstruction);
                }

                if (left->type == DOUBLE || right->type == DOUBLE) {
                    double result = 0;
                    
                    if (left->type == INT) {
                        result -= left->data.intVal;
                    } else if (left->type == DOUBLE) {
                        result -= left->data.doubleVal;
                    }
    
                    if (right->type == INT) {
                        result += right->data.intVal;
                    } else if (right->type == DOUBLE) {
                        result += right->data.doubleVal;
                    }

                    addVariable(scope->variables, in->args.args[2].value.refName, createDoubleGroundValue(result));
                } else {
                    int64_t result = left->data.intVal - right->data.intVal;
                    addVariable(scope->variables, in->args.args[2].value.refName, createIntGroundValue(result));
                }
            } else {
                runtimeError(ARG_TYPE_MISMATCH, "Expecting an Int or Double for arg 1", in, currentInstruction);
            }
            break;
        }
        case MULTIPLY: {
            if (in->args.length < 3) {
                runtimeError(TOO_FEW_ARGS, "Expecting 3 args", in, currentInstruction);
            }
            if (in->args.length > 3) {
                runtimeError(TOO_MANY_ARGS, "Expecting 3 args", in, currentInstruction);
            }
            if (in->args.args[0].type != VALUE) {
                runtimeError(ARG_TYPE_MISMATCH, "Expecting a Value for arg 1", in, currentInstruction);
            }
            if (in->args.args[1].type != VALUE) {
                runtimeError(ARG_TYPE_MISMATCH, "Expecting a Value for arg 2", in, currentInstruction);
            }
            if (in->args.args[2].type != DIRREF) {
                runtimeError(ARG_TYPE_MISMATCH, "Expecting a DirectRef for arg 3", in, currentInstruction);
            }

            GroundValue* left = &in->args.args[0].value.value;
            GroundValue* right = &in->args.args[1].value.value;

            if (left->type == INT || left->type == DOUBLE) {
                if (right->type != INT && right->type != DOUBLE) {
                    runtimeError(ARG_TYPE_MISMATCH, "Expecting an Int or Double for arg 2", in, currentInstruction);
                }

                if (left->type == DOUBLE || right->type == DOUBLE) {
                    double result = 0;
                    
                    if (left->type == INT) {
                        result *= left->data.intVal;
                    } else if (left->type == DOUBLE) {
                        result += left->data.doubleVal;
                    }
    
                    if (right->type == INT) {
                        result *= right->data.intVal;
                    } else if (right->type == DOUBLE) {
                        result += right->data.doubleVal;
                    }

                    addVariable(scope->variables, in->args.args[2].value.refName, createDoubleGroundValue(result));
                } else {
                    int64_t result = left->data.intVal * right->data.intVal;
                    addVariable(scope->variables, in->args.args[2].value.refName, createIntGroundValue(result));
                }
            } else {
                runtimeError(ARG_TYPE_MISMATCH, "Expecting an Int or Double for arg 1", in, currentInstruction);
            }
            break;
        }
        case DIVIDE: {
            if (in->args.length < 3) {
                runtimeError(TOO_FEW_ARGS, "Expecting 3 args", in, currentInstruction);
            }
            if (in->args.length > 3) {
                runtimeError(TOO_MANY_ARGS, "Expecting 3 args", in, currentInstruction);
            }
            if (in->args.args[0].type != VALUE) {
                runtimeError(ARG_TYPE_MISMATCH, "Expecting a Value for arg 1", in, currentInstruction);
            }
            if (in->args.args[1].type != VALUE) {
                runtimeError(ARG_TYPE_MISMATCH, "Expecting a Value for arg 2", in, currentInstruction);
            }
            if (in->args.args[2].type != DIRREF) {
                runtimeError(ARG_TYPE_MISMATCH, "Expecting a DirectRef for arg 3", in, currentInstruction);
            }

            GroundValue* left = &in->args.args[0].value.value;
            GroundValue* right = &in->args.args[1].value.value;

            if (left->type == INT || left->type == DOUBLE) {
                if (right->type != INT && right->type != DOUBLE) {
                    runtimeError(ARG_TYPE_MISMATCH, "Expecting an Int or Double for arg 2", in, currentInstruction);
                }

                if (left->type == DOUBLE || right->type == DOUBLE) {
                    double result = 0;
                    
                    if (left->type == INT) {
                        result /= left->data.intVal;
                    } else if (left->type == DOUBLE) {
                        result /= left->data.doubleVal;
                    }
    
                    if (right->type == INT) {
                        result /= right->data.intVal;
                    } else if (right->type == DOUBLE) {
                        result /= right->data.doubleVal;
                    }

                    addVariable(scope->variables, in->args.args[2].value.refName, createDoubleGroundValue(result));
                } else {
                    int64_t result = left->data.intVal / right->data.intVal;
                    addVariable(scope->variables, in->args.args[2].value.refName, createIntGroundValue(result));
                }
            } else {
                runtimeError(ARG_TYPE_MISMATCH, "Expecting an Int or Double for arg 1", in, currentInstruction);
            }
            break;
        }
        case EQUAL: {
            if (in->args.length < 3) {
                runtimeError(TOO_FEW_ARGS, "Expecting 3 args", in, currentInstruction);
            }
            if (in->args.length > 3) {
                runtimeError(TOO_MANY_ARGS, "Expecting 3 args", in, currentInstruction);
            }
            if (in->args.args[0].type != VALUE) {
                runtimeError(ARG_TYPE_MISMATCH, "Expecting a Value for arg 1", in, currentInstruction);
            }
            if (in->args.args[1].type != VALUE) {
                runtimeError(ARG_TYPE_MISMATCH, "Expecting a Value for arg 2", in, currentInstruction);
            }
            if (in->args.args[2].type != DIRREF) {
                runtimeError(ARG_TYPE_MISMATCH, "Expecting a DirectRef for arg 3", in, currentInstruction);
            }

            GroundValue* left = &in->args.args[0].value.value;
            GroundValue* right = &in->args.args[1].value.value;

            if (left->type != right->type) {
                addVariable(scope->variables, in->args.args[2].value.refName, createBoolGroundValue(false));
            } else {
                switch (left->type) {
                    case INT: {
                        bool cond = (left->data.intVal == right->data.intVal);
                        addVariable(scope->variables, in->args.args[2].value.refName, createBoolGroundValue(cond));
                        break;
                    }
                    case DOUBLE: {
                        bool cond = (left->data.doubleVal == right->data.doubleVal);
                        addVariable(scope->variables, in->args.args[2].value.refName, createBoolGroundValue(cond));
                        break;
                    }
                    case STRING: {
                        bool cond = (strcmp(left->data.stringVal, right->data.stringVal) == 0);
                        addVariable(scope->variables, in->args.args[2].value.refName, createBoolGroundValue(cond));
                        break;
                    }
                    case CHAR: {
                        bool cond = (left->data.charVal == right->data.charVal);
                        addVariable(scope->variables, in->args.args[2].value.refName, createBoolGroundValue(cond));
                        break;
                    }
                    case BOOL: {
                        bool cond = (left->data.boolVal == right->data.boolVal);
                        addVariable(scope->variables, in->args.args[2].value.refName, createBoolGroundValue(cond));
                        break;
                    }
                    default: {
                        addVariable(scope->variables, in->args.args[2].value.refName, createBoolGroundValue(false));
                        break;
                    }
                }
            }
            break;
        }
        default: {
            runtimeError(FIXME, "Currently unimplemented instruction", in, currentInstruction);
        }
    }

    freeGroundInstruction(in);
}