#include "repl_input.h"
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

RavaREPLInput_t* rava_repl_input_create(void) {
    RavaREPLInput_t *input = malloc(sizeof(RavaREPLInput_t));
    if (!input) return NULL;
    input->capacity = RAVA_REPL_MAX_INPUT;
    input->buffer = malloc(input->capacity);
    if (!input->buffer) {
        free(input);
        return NULL;
    }
    input->buffer[0] = '\0';
    input->size = 0;
    input->brace_depth = 0;
    input->bracket_depth = 0;
    input->paren_depth = 0;
    input->in_string = false;
    input->string_delimiter = 0;
    input->line_count = 0;
    return input;
}

void rava_repl_input_destroy(RavaREPLInput_t *input) {
    if (!input) return;
    free(input->buffer);
    free(input);
}

void rava_repl_input_reset(RavaREPLInput_t *input) {
    if (!input) return;
    input->buffer[0] = '\0';
    input->size = 0;
    input->brace_depth = 0;
    input->bracket_depth = 0;
    input->paren_depth = 0;
    input->in_string = false;
    input->string_delimiter = 0;
    input->line_count = 0;
}

static void update_nesting(RavaREPLInput_t *input, const char *line) {
    for (const char *p = line; *p; p++) {
        if (input->in_string) {
            if (*p == '\\' && *(p + 1)) {
                p++;
                continue;
            }
            if (*p == input->string_delimiter) {
                input->in_string = false;
            }
            continue;
        }
        switch (*p) {
            case '"':
            case '\'':
                input->in_string = true;
                input->string_delimiter = *p;
                break;
            case '{':
                input->brace_depth++;
                break;
            case '}':
                input->brace_depth--;
                break;
            case '[':
                input->bracket_depth++;
                break;
            case ']':
                input->bracket_depth--;
                break;
            case '(':
                input->paren_depth++;
                break;
            case ')':
                input->paren_depth--;
                break;
            case '/':
                if (*(p + 1) == '/') {
                    return;
                }
                break;
        }
    }
}

static bool ends_with_operator(const char *line) {
    size_t len = strlen(line);
    while (len > 0 && isspace(line[len - 1])) len--;
    if (len == 0) return false;
    char last = line[len - 1];
    if (last == '+' || last == '-' || last == '*' || last == '/' || last == '%' ||
        last == '&' || last == '|' || last == '^' || last == '=' || last == '<' ||
        last == '>' || last == '!' || last == '?' || last == ':' || last == ',') {
        return true;
    }
    return false;
}

RavaREPLInputState_e rava_repl_input_append(RavaREPLInput_t *input, const char *line) {
    if (!input || !line) return RAVA_REPL_INPUT_ERROR;
    size_t line_len = strlen(line);
    if (input->size + line_len + 2 > input->capacity) {
        return RAVA_REPL_INPUT_ERROR;
    }
    if (input->size > 0) {
        input->buffer[input->size++] = '\n';
    }
    memcpy(input->buffer + input->size, line, line_len);
    input->size += line_len;
    input->buffer[input->size] = '\0';
    input->line_count++;
    update_nesting(input, line);
    if (input->in_string) return RAVA_REPL_INPUT_CONTINUE;
    if (input->brace_depth > 0) return RAVA_REPL_INPUT_CONTINUE;
    if (input->bracket_depth > 0) return RAVA_REPL_INPUT_CONTINUE;
    if (input->paren_depth > 0) return RAVA_REPL_INPUT_CONTINUE;
    if (ends_with_operator(input->buffer)) return RAVA_REPL_INPUT_CONTINUE;
    return RAVA_REPL_INPUT_COMPLETE;
}

const char* rava_repl_input_get(RavaREPLInput_t *input) {
    if (!input) return NULL;
    return input->buffer;
}

bool rava_repl_input_is_empty(RavaREPLInput_t *input) {
    if (!input) return true;
    return input->size == 0;
}

static bool starts_with_keyword(const char *code, const char *keyword) {
    size_t len = strlen(keyword);
    if (strncmp(code, keyword, len) != 0) return false;
    char next = code[len];
    return next == ' ' || next == '\t' || next == '\n' || next == '(' || next == '{' || next == '[';
}

RavaREPLCodeType_e rava_repl_input_detect_type(const char *code) {
    while (*code && isspace(*code)) code++;
    if (starts_with_keyword(code, "public") ||
        starts_with_keyword(code, "private") ||
        starts_with_keyword(code, "protected")) {
        const char *p = code;
        while (*p && !isspace(*p)) p++;
        while (*p && isspace(*p)) p++;
        if (starts_with_keyword(p, "class")) {
            return RAVA_REPL_CODE_CLASS_DECL;
        }
        if (starts_with_keyword(p, "static")) {
            p += 6;
            while (*p && isspace(*p)) p++;
        }
        bool has_paren = false;
        const char *scan = p;
        while (*scan && *scan != ';' && *scan != '{') {
            if (*scan == '(') {
                has_paren = true;
                break;
            }
            scan++;
        }
        if (has_paren) {
            return RAVA_REPL_CODE_METHOD_DECL;
        }
        return RAVA_REPL_CODE_VAR_DECL;
    }
    if (starts_with_keyword(code, "class")) {
        return RAVA_REPL_CODE_CLASS_DECL;
    }
    if (starts_with_keyword(code, "interface")) {
        return RAVA_REPL_CODE_CLASS_DECL;
    }
    if (starts_with_keyword(code, "enum")) {
        return RAVA_REPL_CODE_CLASS_DECL;
    }
    if (starts_with_keyword(code, "int") ||
        starts_with_keyword(code, "long") ||
        starts_with_keyword(code, "double") ||
        starts_with_keyword(code, "float") ||
        starts_with_keyword(code, "boolean") ||
        starts_with_keyword(code, "char") ||
        starts_with_keyword(code, "byte") ||
        starts_with_keyword(code, "short") ||
        starts_with_keyword(code, "String") ||
        starts_with_keyword(code, "void")) {
        const char *p = code;
        while (*p && !isspace(*p) && *p != '[') p++;
        if (*p == '[') {
            while (*p == '[' || *p == ']' || isspace(*p)) p++;
        }
        while (*p && isspace(*p)) p++;
        while (*p && (isalnum(*p) || *p == '_')) p++;
        while (*p && isspace(*p)) p++;
        if (*p == '[') {
            while (*p == '[' || *p == ']' || isspace(*p)) p++;
        }
        if (*p == '(') {
            return RAVA_REPL_CODE_METHOD_DECL;
        }
        if (*p == '=' || *p == ';' || *p == ',') {
            return RAVA_REPL_CODE_VAR_DECL;
        }
    }
    if (starts_with_keyword(code, "if") ||
        starts_with_keyword(code, "while") ||
        starts_with_keyword(code, "for") ||
        starts_with_keyword(code, "do") ||
        starts_with_keyword(code, "switch") ||
        starts_with_keyword(code, "try") ||
        starts_with_keyword(code, "return") ||
        starts_with_keyword(code, "break") ||
        starts_with_keyword(code, "continue") ||
        starts_with_keyword(code, "throw")) {
        return RAVA_REPL_CODE_STATEMENT;
    }
    const char *p = code;
    if (isupper(*p)) {
        while (*p && (isalnum(*p) || *p == '_')) p++;
        if (*p == '[') {
            while (*p == '[' || *p == ']' || isspace(*p)) p++;
        }
        while (*p && isspace(*p)) p++;
        if (islower(*p) || *p == '_') {
            const char *var_start = p;
            while (*p && (isalnum(*p) || *p == '_')) p++;
            if (p > var_start) {
                while (*p && isspace(*p)) p++;
                if (*p == '=' || *p == ';') {
                    return RAVA_REPL_CODE_VAR_DECL;
                }
            }
        }
    }

    p = code;
    bool has_semicolon = false;
    bool has_assign = false;
    while (*p) {
        if (*p == ';') has_semicolon = true;
        if (*p == '=' && *(p+1) != '=') has_assign = true;
        p++;
    }
    if (has_assign && has_semicolon) {
        return RAVA_REPL_CODE_STATEMENT;
    }
    return RAVA_REPL_CODE_EXPRESSION;
}