#include "pocketpy/lexer.h"

namespace pkpy{


static const uint32_t kLoRangeA[] = {170,186,443,448,660,1488,1519,1568,1601,1646,1649,1749,1774,1786,1791,1808,1810,1869,1969,1994,2048,2112,2144,2208,2230,2308,2365,2384,2392,2418,2437,2447,2451,2474,2482,2486,2493,2510,2524,2527,2544,2556,2565,2575,2579,2602,2610,2613,2616,2649,2654,2674,2693,2703,2707,2730,2738,2741,2749,2768,2784,2809,2821,2831,2835,2858,2866,2869,2877,2908,2911,2929,2947,2949,2958,2962,2969,2972,2974,2979,2984,2990,3024,3077,3086,3090,3114,3133,3160,3168,3200,3205,3214,3218,3242,3253,3261,3294,3296,3313,3333,3342,3346,3389,3406,3412,3423,3450,3461,3482,3507,3517,3520,3585,3634,3648,3713,3716,3718,3724,3749,3751,3762,3773,3776,3804,3840,3904,3913,3976,4096,4159,4176,4186,4193,4197,4206,4213,4238,4352,4682,4688,4696,4698,4704,4746,4752,4786,4792,4800,4802,4808,4824,4882,4888,4992,5121,5743,5761,5792,5873,5888,5902,5920,5952,5984,5998,6016,6108,6176,6212,6272,6279,6314,6320,6400,6480,6512,6528,6576,6656,6688,6917,6981,7043,7086,7098,7168,7245,7258,7401,7406,7413,7418,8501,11568,11648,11680,11688,11696,11704,11712,11720,11728,11736,12294,12348,12353,12447,12449,12543,12549,12593,12704,12784,13312,19968,40960,40982,42192,42240,42512,42538,42606,42656,42895,42999,43003,43011,43015,43020,43072,43138,43250,43259,43261,43274,43312,43360,43396,43488,43495,43514,43520,43584,43588,43616,43633,43642,43646,43697,43701,43705,43712,43714,43739,43744,43762,43777,43785,43793,43808,43816,43968,44032,55216,55243,63744,64112,64285,64287,64298,64312,64318,64320,64323,64326,64467,64848,64914,65008,65136,65142,65382,65393,65440,65474,65482,65490,65498,65536,65549,65576,65596,65599,65616,65664,66176,66208,66304,66349,66370,66384,66432,66464,66504,66640,66816,66864,67072,67392,67424,67584,67592,67594,67639,67644,67647,67680,67712,67808,67828,67840,67872,67968,68030,68096,68112,68117,68121,68192,68224,68288,68297,68352,68416,68448,68480,68608,68864,69376,69415,69424,69600,69635,69763,69840,69891,69956,69968,70006,70019,70081,70106,70108,70144,70163,70272,70280,70282,70287,70303,70320,70405,70415,70419,70442,70450,70453,70461,70480,70493,70656,70727,70751,70784,70852,70855,71040,71128,71168,71236,71296,71352,71424,71680,71935,72096,72106,72161,72163,72192,72203,72250,72272,72284,72349,72384,72704,72714,72768,72818,72960,72968,72971,73030,73056,73063,73066,73112,73440,73728,74880,77824,82944,92160,92736,92880,92928,93027,93053,93952,94032,94208,100352,110592,110928,110948,110960,113664,113776,113792,113808,123136,123214,123584,124928,126464,126469,126497,126500,126503,126505,126516,126521,126523,126530,126535,126537,126539,126541,126545,126548,126551,126553,126555,126557,126559,126561,126564,126567,126572,126580,126585,126590,126592,126603,126625,126629,126635,131072,173824,177984,178208,183984,194560};
static const uint32_t kLoRangeB[] = {170,186,443,451,660,1514,1522,1599,1610,1647,1747,1749,1775,1788,1791,1808,1839,1957,1969,2026,2069,2136,2154,2228,2237,2361,2365,2384,2401,2432,2444,2448,2472,2480,2482,2489,2493,2510,2525,2529,2545,2556,2570,2576,2600,2608,2611,2614,2617,2652,2654,2676,2701,2705,2728,2736,2739,2745,2749,2768,2785,2809,2828,2832,2856,2864,2867,2873,2877,2909,2913,2929,2947,2954,2960,2965,2970,2972,2975,2980,2986,3001,3024,3084,3088,3112,3129,3133,3162,3169,3200,3212,3216,3240,3251,3257,3261,3294,3297,3314,3340,3344,3386,3389,3406,3414,3425,3455,3478,3505,3515,3517,3526,3632,3635,3653,3714,3716,3722,3747,3749,3760,3763,3773,3780,3807,3840,3911,3948,3980,4138,4159,4181,4189,4193,4198,4208,4225,4238,4680,4685,4694,4696,4701,4744,4749,4784,4789,4798,4800,4805,4822,4880,4885,4954,5007,5740,5759,5786,5866,5880,5900,5905,5937,5969,5996,6000,6067,6108,6210,6264,6276,6312,6314,6389,6430,6509,6516,6571,6601,6678,6740,6963,6987,7072,7087,7141,7203,7247,7287,7404,7411,7414,7418,8504,11623,11670,11686,11694,11702,11710,11718,11726,11734,11742,12294,12348,12438,12447,12538,12543,12591,12686,12730,12799,19893,40943,40980,42124,42231,42507,42527,42539,42606,42725,42895,42999,43009,43013,43018,43042,43123,43187,43255,43259,43262,43301,43334,43388,43442,43492,43503,43518,43560,43586,43595,43631,43638,43642,43695,43697,43702,43709,43712,43714,43740,43754,43762,43782,43790,43798,43814,43822,44002,55203,55238,55291,64109,64217,64285,64296,64310,64316,64318,64321,64324,64433,64829,64911,64967,65019,65140,65276,65391,65437,65470,65479,65487,65495,65500,65547,65574,65594,65597,65613,65629,65786,66204,66256,66335,66368,66377,66421,66461,66499,66511,66717,66855,66915,67382,67413,67431,67589,67592,67637,67640,67644,67669,67702,67742,67826,67829,67861,67897,68023,68031,68096,68115,68119,68149,68220,68252,68295,68324,68405,68437,68466,68497,68680,68899,69404,69415,69445,69622,69687,69807,69864,69926,69956,70002,70006,70066,70084,70106,70108,70161,70187,70278,70280,70285,70301,70312,70366,70412,70416,70440,70448,70451,70457,70461,70480,70497,70708,70730,70751,70831,70853,70855,71086,71131,71215,71236,71338,71352,71450,71723,71935,72103,72144,72161,72163,72192,72242,72250,72272,72329,72349,72440,72712,72750,72768,72847,72966,72969,73008,73030,73061,73064,73097,73112,73458,74649,75075,78894,83526,92728,92766,92909,92975,93047,93071,94026,94032,100343,101106,110878,110930,110951,111355,113770,113788,113800,113817,123180,123214,123627,125124,126467,126495,126498,126500,126503,126514,126519,126521,126523,126530,126535,126537,126539,126543,126546,126548,126551,126553,126555,126557,126559,126562,126564,126570,126578,126583,126588,126590,126601,126619,126627,126633,126651,173782,177972,178205,183969,191456,195101};

static bool is_possible_number_char(char c){
    switch(c){
        case '0': case '1': case '2': case '3': case '4': case '5': case '6': case '7': case '8': case '9':
        case 'a': case 'b': case 'c': case 'd': case 'e': case 'f':
        case 'A': case 'B': case 'C': case 'D': case 'E': case 'F':
        case '.': case 'L': case 'x': case 'o': case 'j': return true;
        default: return false;
    }
}

static bool is_unicode_Lo_char(uint32_t c) {
    // open a hole for carrot
    if(c == U'🥕') return true;
    auto index = std::lower_bound(kLoRangeA, kLoRangeA + 476, c) - kLoRangeA;
    if(c == kLoRangeA[index]) return true;
    index -= 1;
    if(index < 0) return false;
    return c >= kLoRangeA[index] && c <= kLoRangeB[index];
}

    bool Lexer::match_n_chars(int n, char c0){
        const char* c = curr_char;
        for(int i=0; i<n; i++){
            if(*c == '\0') return false;
            if(*c != c0) return false;
            c++;
        }
        for(int i=0; i<n; i++) eatchar_include_newline();
        return true;
    }

    bool Lexer::match_string(const char* s){
        int s_len = strlen(s);
        bool ok = strncmp(curr_char, s, s_len) == 0;
        if(ok) for(int i=0; i<s_len; i++) eatchar_include_newline();
        return ok;
    }

    int Lexer::eat_spaces(){
        int count = 0;
        while (true) {
            switch (peekchar()) {
                case ' ' : count+=1; break;
                case '\t': count+=4; break;
                default: return count;
            }
            eatchar();
        }
    }

    bool Lexer::eat_indentation(){
        if(brackets_level > 0) return true;
        int spaces = eat_spaces();
        if(peekchar() == '#') skip_line_comment();
        if(peekchar() == '\0' || peekchar() == '\n') return true;
        // https://docs.python.org/3/reference/lexical_analysis.html#indentation
        if(spaces > indents.top()){
            indents.push(spaces);
            nexts.push_back(Token{TK("@indent"), token_start, 0, current_line, brackets_level, {}});
        } else if(spaces < indents.top()){
            while(spaces < indents.top()){
                indents.pop();
                nexts.push_back(Token{TK("@dedent"), token_start, 0, current_line, brackets_level, {}});
            }
            if(spaces != indents.top()){
                return false;
            }
        }
        return true;
    }

    char Lexer::eatchar() {
        char c = peekchar();
        if(c == '\n') throw std::runtime_error("eatchar() cannot consume a newline");
        curr_char++;
        return c;
    }

    char Lexer::eatchar_include_newline() {
        char c = peekchar();
        curr_char++;
        if (c == '\n'){
            current_line++;
            src->line_starts.push_back(curr_char);
        }
        return c;
    }

    int Lexer::eat_name() {
        curr_char--;
        while(true){
            unsigned char c = peekchar();
            int u8bytes = utf8len(c, true);
            if(u8bytes == 0) return 1;
            if(u8bytes == 1){
                if(isalpha(c) || c=='_' || isdigit(c)) {
                    curr_char++;
                    continue;
                }else{
                    break;
                }
            }
            // handle multibyte char
            Str u8str(curr_char, u8bytes);
            if(u8str.size != u8bytes) return 2;
            uint32_t value = 0;
            for(int k=0; k < u8bytes; k++){
                uint8_t b = u8str[k];
                if(k==0){
                    if(u8bytes == 2) value = (b & 0b00011111) << 6;
                    else if(u8bytes == 3) value = (b & 0b00001111) << 12;
                    else if(u8bytes == 4) value = (b & 0b00000111) << 18;
                }else{
                    value |= (b & 0b00111111) << (6*(u8bytes-k-1));
                }
            }
            if(is_unicode_Lo_char(value)) curr_char += u8bytes;
            else break;
        }

        int length = (int)(curr_char - token_start);
        if(length == 0) return 3;
        std::string_view name(token_start, length);

        if(src->mode == JSON_MODE){
            if(name == "true"){
                add_token(TK("True"));
            } else if(name == "false"){
                add_token(TK("False"));
            } else if(name == "null"){
                add_token(TK("None"));
            } else {
                return 4;
            }
            return 0;
        }

        if(kTokenKwMap.count(name)){
            add_token(kTokenKwMap.at(name));
        } else {
            add_token(TK("@id"));
        }
        return 0;
    }

    void Lexer::skip_line_comment() {
        char c;
        while ((c = peekchar()) != '\0') {
            if (c == '\n') return;
            eatchar();
        }
    }
    
    bool Lexer::matchchar(char c) {
        if (peekchar() != c) return false;
        eatchar_include_newline();
        return true;
    }

    void Lexer::add_token(TokenIndex type, TokenValue value) {
        switch(type){
            case TK("{"): case TK("["): case TK("("): brackets_level++; break;
            case TK(")"): case TK("]"): case TK("}"): brackets_level--; break;
        }
        auto token = Token{
            type,
            token_start,
            (int)(curr_char - token_start),
            current_line - ((type == TK("@eol")) ? 1 : 0),
            brackets_level,
            value
        };
        // handle "not in", "is not", "yield from"
        if(!nexts.empty()){
            auto& back = nexts.back();
            if(back.type == TK("not") && type == TK("in")){
                back.type = TK("not in");
                return;
            }
            if(back.type == TK("is") && type == TK("not")){
                back.type = TK("is not");
                return;
            }
            if(back.type == TK("yield") && type == TK("from")){
                back.type = TK("yield from");
                return;
            }
            nexts.push_back(token);
        }
    }

    void Lexer::add_token_2(char c, TokenIndex one, TokenIndex two) {
        if (matchchar(c)) add_token(two);
        else add_token(one);
    }

    Str Lexer::eat_string_until(char quote, bool raw) {
        bool quote3 = match_n_chars(2, quote);
        small_vector_2<char, 32> buff;
        while (true) {
            char c = eatchar_include_newline();
            if (c == quote){
                if(quote3 && !match_n_chars(2, quote)){
                    buff.push_back(c);
                    continue;
                }
                break;
            }
            if (c == '\0'){
                if(quote3 && src->mode == REPL_MODE){
                    throw NeedMoreLines(false);
                }
                SyntaxError("EOL while scanning string literal");
            }
            if (c == '\n'){
                if(!quote3) SyntaxError("EOL while scanning string literal");
                else{
                    buff.push_back(c);
                    continue;
                }
            }
            if (!raw && c == '\\') {
                switch (eatchar_include_newline()) {
                    case '"':  buff.push_back('"');  break;
                    case '\'': buff.push_back('\''); break;
                    case '\\': buff.push_back('\\'); break;
                    case 'n':  buff.push_back('\n'); break;
                    case 'r':  buff.push_back('\r'); break;
                    case 't':  buff.push_back('\t'); break;
                    case 'b':  buff.push_back('\b'); break;
                    case 'x': {
                        char hex[3] = {eatchar(), eatchar(), '\0'};
                        size_t parsed;
                        char code;
                        try{
                            code = (char)std::stoi(hex, &parsed, 16);
                        }catch(...){
                            SyntaxError("invalid hex char");
                        }
                        if (parsed != 2) SyntaxError("invalid hex char");
                        buff.push_back(code);
                    } break;
                    default: SyntaxError("invalid escape char");
                }
            } else {
                buff.push_back(c);
            }
        }
        return Str(buff.data(), buff.size());
    }

    void Lexer::eat_string(char quote, StringType type) {
        Str s = eat_string_until(quote, type == RAW_STRING);
        if(type == F_STRING){
            add_token(TK("@fstr"), s);
            return;
        }
        if(type == NORMAL_BYTES){
            add_token(TK("@bytes"), s);
            return;
        }
        add_token(TK("@str"), s);
    }

    void Lexer::eat_number() {
        const char* i = token_start;
        while(is_possible_number_char(*i)) i++;

        bool is_scientific_notation = false;
        if(*(i-1) == 'e' && (*i == '+' || *i == '-')){
            i++;
            while(isdigit(*i) || *i=='j') i++;
            is_scientific_notation = true;
        }

        std::string_view text(token_start, i - token_start);
        this->curr_char = i;

        if(text[0] != '.' && !is_scientific_notation){
            // try long
            if(i[-1] == 'L'){
                add_token(TK("@long"));
                return;
            }
            // try integer
            i64 int_out;
            switch(parse_uint(text, &int_out, -1)){
                case IntParsingResult::Success:
                    add_token(TK("@num"), int_out);
                    return;
                case IntParsingResult::Overflow:
                    SyntaxError("int literal is too large");
                    return;
                case IntParsingResult::Failure:
                    break;  // do nothing
            }
        }

        // try float
        double float_out;
        char* p_end;
        try{
            float_out = std::strtod(text.data(), &p_end);
        }catch(...){
            SyntaxError("invalid number literal");
        }
        
        if(p_end == text.data() + text.size()){
            add_token(TK("@num"), (f64)float_out);
            return;
        }

        if(i[-1] == 'j' && p_end == text.data() + text.size() - 1){
            add_token(TK("@imag"), (f64)float_out);
            return;
        }

        SyntaxError("invalid number literal");
    }

    bool Lexer::lex_one_token() {
        while (peekchar() != '\0') {
            token_start = curr_char;
            char c = eatchar_include_newline();
            switch (c) {
                case '\'': case '"': eat_string(c, NORMAL_STRING); return true;
                case '#': skip_line_comment(); break;
                case '~': add_token(TK("~")); return true;
                case '{': add_token(TK("{")); return true;
                case '}': add_token(TK("}")); return true;
                case ',': add_token(TK(",")); return true;
                case ':': add_token(TK(":")); return true;
                case ';': add_token(TK(";")); return true;
                case '(': add_token(TK("(")); return true;
                case ')': add_token(TK(")")); return true;
                case '[': add_token(TK("[")); return true;
                case ']': add_token(TK("]")); return true;
                case '@': add_token(TK("@")); return true;
                case '\\': {
                    // line continuation character
                    char c = eatchar_include_newline();
                    if (c != '\n'){
                        if(src->mode == REPL_MODE && c == '\0') throw NeedMoreLines(false);
                        SyntaxError("expected newline after line continuation character");
                    }
                    eat_spaces();
                    return true;
                }
                case '%': add_token_2('=', TK("%"), TK("%=")); return true;
                case '&': add_token_2('=', TK("&"), TK("&=")); return true;
                case '|': add_token_2('=', TK("|"), TK("|=")); return true;
                case '^': add_token_2('=', TK("^"), TK("^=")); return true;
                case '.': {
                    if(matchchar('.')) {
                        if(matchchar('.')) {
                            add_token(TK("..."));
                        } else {
                            add_token(TK(".."));
                        }
                    } else {
                        char next_char = peekchar();
                        if(next_char >= '0' && next_char <= '9'){
                            eat_number();
                        }else{
                            add_token(TK("."));
                        }
                    }
                    return true;
                }
                case '=': add_token_2('=', TK("="), TK("==")); return true;
                case '+':
                    if(matchchar('+')){
                        add_token(TK("++"));
                    }else{
                        add_token_2('=', TK("+"), TK("+="));
                    }
                    return true;
                case '>': {
                    if(matchchar('=')) add_token(TK(">="));
                    else if(matchchar('>')) add_token_2('=', TK(">>"), TK(">>="));
                    else add_token(TK(">"));
                    return true;
                }
                case '<': {
                    if(matchchar('=')) add_token(TK("<="));
                    else if(matchchar('<')) add_token_2('=', TK("<<"), TK("<<="));
                    else add_token(TK("<"));
                    return true;
                }
                case '-': {
                    if(matchchar('-')){
                        add_token(TK("--"));
                    }else{
                        if(matchchar('=')) add_token(TK("-="));
                        else if(matchchar('>')) add_token(TK("->"));
                        else add_token(TK("-"));
                    }
                    return true;
                }
                case '!':
                    if(matchchar('=')) add_token(TK("!="));
                    else SyntaxError("expected '=' after '!'");
                    break;
                case '*':
                    if (matchchar('*')) {
                        add_token(TK("**"));  // '**'
                    } else {
                        add_token_2('=', TK("*"), TK("*="));
                    }
                    return true;
                case '/':
                    if(matchchar('/')) {
                        add_token_2('=', TK("//"), TK("//="));
                    } else {
                        add_token_2('=', TK("/"), TK("/="));
                    }
                    return true;
                case ' ': case '\t': eat_spaces(); break;
                case '\n': {
                    add_token(TK("@eol"));
                    if(!eat_indentation()) IndentationError("unindent does not match any outer indentation level");
                    return true;
                }
                default: {
                    if(c == 'f'){
                        if(matchchar('\'')) {eat_string('\'', F_STRING); return true;}
                        if(matchchar('"')) {eat_string('"', F_STRING); return true;}
                    }else if(c == 'r'){
                        if(matchchar('\'')) {eat_string('\'', RAW_STRING); return true;}
                        if(matchchar('"')) {eat_string('"', RAW_STRING); return true;}
                    }else if(c == 'b'){
                        if(matchchar('\'')) {eat_string('\'', NORMAL_BYTES); return true;}
                        if(matchchar('"')) {eat_string('"', NORMAL_BYTES); return true;}
                    }
                    if (c >= '0' && c <= '9') {
                        eat_number();
                        return true;
                    }
                    switch (eat_name())
                    {
                        case 0: break;
                        case 1: SyntaxError("invalid char: " + std::string(1, c)); break;
                        case 2: SyntaxError("invalid utf8 sequence: " + std::string(1, c)); break;
                        case 3: SyntaxError("@id contains invalid char"); break;
                        case 4: SyntaxError("invalid JSON token"); break;
                        default: PK_FATAL_ERROR();
                    }
                    return true;
                }
            }
        }

        token_start = curr_char;
        while(indents.size() > 1){
            indents.pop();
            add_token(TK("@dedent"));
            return true;
        }
        add_token(TK("@eof"));
        return false;
    }

    void Lexer::throw_err(StrName type, Str msg){
        int lineno = current_line;
        const char* cursor = curr_char;
        if(peekchar() == '\n'){
            lineno--;
            cursor--;
        }
        throw_err(type, msg, lineno, cursor);
    }

    Lexer::Lexer(VM* vm, std::shared_ptr<SourceData> src) : vm(vm), src(src) {
        this->token_start = src->source.c_str();
        this->curr_char = src->source.c_str();
        this->nexts.push_back(Token{TK("@sof"), token_start, 0, current_line, brackets_level, {}});
        this->indents.push(0);
    }

    vector<Token> Lexer::run() {
        PK_ASSERT(curr_char == src->source.c_str());
        while (lex_one_token());
        return std::move(nexts);
    }

inline constexpr bool f_startswith_2(std::string_view t, const char* prefix){
    if(t.length() < 2) return false;
    return t[0] == prefix[0] && t[1] == prefix[1];
}

IntParsingResult parse_uint(std::string_view text, i64* out, int base){
  *out = 0;

  if(base == -1){
    if(f_startswith_2(text, "0b")) base = 2;
    else if(f_startswith_2(text, "0o")) base = 8;
    else if(f_startswith_2(text, "0x")) base = 16;
    else base = 10;
  }

  if(base == 10){
    // 10-base  12334
    if(text.length() == 0) return IntParsingResult::Failure;
    for(char c : text){
      if(c >= '0' && c <= '9'){
        i64 prev_out = *out;
        *out = (*out * 10) + (c - '0');
        if(*out < prev_out) return IntParsingResult::Overflow;
      }else{
        return IntParsingResult::Failure;
      }
    }
    return IntParsingResult::Success;
  }else if(base == 2){
    // 2-base   0b101010
    if(f_startswith_2(text, "0b")) text.remove_prefix(2);
    if(text.length() == 0) return IntParsingResult::Failure;
    for(char c : text){
      if(c == '0' || c == '1'){
        i64 prev_out = *out;
        *out = (*out << 1) | (c - '0');
        if(*out < prev_out) return IntParsingResult::Overflow;
      }else{
        return IntParsingResult::Failure;
      }
    }
    return IntParsingResult::Success;
  }else if(base == 8){
    // 8-base   0o123
    if(f_startswith_2(text, "0o")) text.remove_prefix(2);
    if(text.length() == 0) return IntParsingResult::Failure;
    for(char c : text){
      if(c >= '0' && c <= '7'){
        i64 prev_out = *out;
        *out = (*out << 3) | (c - '0');
        if(*out < prev_out) return IntParsingResult::Overflow;
      }else{
        return IntParsingResult::Failure;
      }
    }
    return IntParsingResult::Success;
  }else if(base == 16){
    // 16-base  0x123
    if(f_startswith_2(text, "0x")) text.remove_prefix(2);
    if(text.length() == 0) return IntParsingResult::Failure;
    for(char c : text){
      i64 prev_out = *out;
      if(c >= '0' && c <= '9'){
        *out = (*out << 4) | (c - '0');
        if(*out < prev_out) return IntParsingResult::Overflow;
      }else if(c >= 'a' && c <= 'f'){
        *out = (*out << 4) | (c - 'a' + 10);
        if(*out < prev_out) return IntParsingResult::Overflow;
      }else if(c >= 'A' && c <= 'F'){
        *out = (*out << 4) | (c - 'A' + 10);
        if(*out < prev_out) return IntParsingResult::Overflow;
      }else{
        return IntParsingResult::Failure;
      }
    }
    return IntParsingResult::Success;
  }
  return IntParsingResult::Failure;
}

}   // namespace pkpy