/*
 * Helpers for doing long range seeks.
 */

// TOP

#if !defined(FCODER_LONG_SEEK_H)
#define FCODER_LONG_SEEK_H

#include "4coder_helper/4coder_streaming.h"
#include "4coder_lib/4coder_mem.h"
#include "4cpp/4cpp_lexer.h"

//
// Whitespace Based Seeks
//

static int32_t
seek_line_end(Application_Links *app, Buffer_Summary *buffer, int32_t pos){
    char chunk[1024];
    int32_t chunk_size = sizeof(chunk);
    Stream_Chunk stream = {0};
    
    int32_t still_looping;
    char at_pos;
    
    if (init_stream_chunk(&stream, app, buffer, pos, chunk, chunk_size)){
        still_looping = 1;
        do{
            for (; pos < stream.end; ++pos){
                at_pos = stream.data[pos];
                if (at_pos == '\n'){
                    goto double_break;
                }
            }
            still_looping = forward_stream_chunk(&stream);
        }while(still_looping);
        double_break:;
        
        if (pos > buffer->size){
            pos = buffer->size;
        }
    }
    
    return(pos);
}

static int32_t
seek_line_beginning(Application_Links *app, Buffer_Summary *buffer, int32_t pos){
    char chunk[1024];
    int32_t chunk_size = sizeof(chunk);
    Stream_Chunk stream = {0};
    
    int32_t still_looping;
    char at_pos;
    
    --pos;
    if (init_stream_chunk(&stream, app, buffer, pos, chunk, chunk_size)){
        still_looping = 1;
        do{
            for (; pos >= stream.start; --pos){
                at_pos = stream.data[pos];
                if (at_pos == '\n'){
                    goto double_break;
                }
            }
            still_looping = backward_stream_chunk(&stream);
        }while(still_looping);
        double_break:;
        
        if (pos != 0){
            ++pos;
        }
        if (pos < 0){
            pos = 0;
        }
    }
    
    return(pos);
}

static void
move_past_lead_whitespace(Application_Links *app, View_Summary *view, Buffer_Summary *buffer){
    refresh_view(app, view);
    
    int32_t new_pos = seek_line_beginning(app, buffer, view->cursor.pos);
    char space[1024];
    Stream_Chunk chunk = {0};
    int32_t still_looping = false;
    
    int32_t i = new_pos;
    if (init_stream_chunk(&chunk, app, buffer, i, space, sizeof(space))){
        do{
            for (; i < chunk.end; ++i){
                char at_pos = chunk.data[i];
                if (at_pos == '\n' || !char_is_whitespace(at_pos)){
                    goto break2;
                }
            }
            still_looping = forward_stream_chunk(&chunk);
        }while(still_looping);
        break2:;
        
        if (i > view->cursor.pos){
            view_set_cursor(app, view, seek_pos(i), true);
        }
    }
}

static int32_t
buffer_seek_whitespace_up(Application_Links *app, Buffer_Summary *buffer, int32_t pos){
    char chunk[1024];
    int32_t chunk_size = sizeof(chunk);
    Stream_Chunk stream = {0};
    
    char at_pos;
    
    --pos;
    if (init_stream_chunk(&stream, app, buffer, pos, chunk, chunk_size)){
        // Step 1: Find the first non-whitespace character
        // behind the current position.
        int32_t still_looping = 1;
        while (still_looping){
            for (; pos >= stream.start; --pos){
                at_pos = stream.data[pos];
                if (!char_is_whitespace(at_pos)){
                    goto double_break_1;
                }
            }
            still_looping = backward_stream_chunk(&stream);
        }
        double_break_1:;
        
        // Step 2: Continue scanning backward, at each '\n'
        // mark the beginning of another line by setting
        // no_hard to true, set it back to false if a
        // non-whitespace character is discovered before
        // the next '\n'
        int32_t no_hard = false;
        while (still_looping){
            for (; pos >= stream.start; --pos){
                at_pos = stream.data[pos];
                if (at_pos == '\n'){
                    if (no_hard){
                        goto double_break_2;
                    }
                    else{
                        no_hard = true;
                    }
                }
                else if (!char_is_whitespace(at_pos)){
                    no_hard = false;
                }
            }
            still_looping = backward_stream_chunk(&stream);
        }
        double_break_2:;
        
        if (pos != 0){
            ++pos;
        }
    }
    
    return(pos);
}

static int32_t
buffer_seek_whitespace_down(Application_Links *app, Buffer_Summary *buffer, int32_t pos){
    char chunk[1024];
    int32_t chunk_size = sizeof(chunk);
    Stream_Chunk stream = {0};
    
    if (init_stream_chunk(&stream, app, buffer, pos, chunk, chunk_size)){
        // step 1: find the first non-whitespace character
        // ahead of the current position.
        bool32 still_looping = true;
        do{
            for (; pos < stream.end; ++pos){
                char at_pos = stream.data[pos];
                if (!char_is_whitespace(at_pos)){
                    goto double_break_1;
                }
            }
            still_looping = forward_stream_chunk(&stream);
        } while(still_looping);
        double_break_1:;
        
        // step 2: continue scanning forward, at each '\n'
        // mark it as the beginning of a new line by updating
        // the prev_endline value.  if another '\n' is found
        // with non-whitespace then the previous line was
        // all whitespace.
        bool32 no_hard = false;
        int32_t prev_endline = -1;
        while(still_looping){
            for (; pos < stream.end; ++pos){
                char at_pos = stream.data[pos];
                if (at_pos == '\n'){
                    if (no_hard){
                        goto double_break_2;
                    }
                    else{
                        no_hard = true;
                        prev_endline = pos;
                    }
                }
                else if (!char_is_whitespace(at_pos)){
                    no_hard = false;
                }
            }
            still_looping = forward_stream_chunk(&stream);
        }
        double_break_2:;
        
        if (prev_endline == -1 || prev_endline+1 >= buffer->size){
            pos = buffer->size;
        }
        else{
            pos = prev_endline+1;
        }
    }
    
    return(pos);
}
static int32_t
buffer_seek_whitespace_right(Application_Links *app, Buffer_Summary *buffer, int32_t pos){
    char data_chunk[1024];
    Stream_Chunk stream = {0};
    
    if (init_stream_chunk(&stream, app, buffer, pos, data_chunk, sizeof(data_chunk))){
        
        bool32 still_looping = true;
        do{
            for (; pos < stream.end; ++pos){
                if (!char_is_whitespace(stream.data[pos])){
                    goto double_break1;
                }
            }
            still_looping = forward_stream_chunk(&stream);
        }while(still_looping);
        double_break1:;
        
        still_looping = true;
        do{
            for (; pos < stream.end; ++pos){
                if (char_is_whitespace(stream.data[pos])){
                    goto double_break2;
                }
            }
            still_looping = forward_stream_chunk(&stream);
        }while(still_looping);
        double_break2:;
    }
    
    return(pos);
}

static int32_t
buffer_seek_whitespace_left(Application_Links *app, Buffer_Summary *buffer, int32_t pos){
    char data_chunk[1024];
    Stream_Chunk stream = {0};
    
    --pos;
    if (pos > 0){
        if (init_stream_chunk(&stream, app, buffer,
                              pos, data_chunk, sizeof(data_chunk))){
            
            bool32 still_looping = 1;
            do{
                for (; pos >= stream.start; --pos){
                    if (!char_is_whitespace(stream.data[pos])){
                        goto double_break1;
                    }
                }
                still_looping = backward_stream_chunk(&stream);
            }while(still_looping);
            double_break1:;
            
            still_looping = 1;
            do{
                for (; pos >= stream.start; --pos){
                    if (char_is_whitespace(stream.data[pos])){
                        ++pos;
                        goto double_break2;
                    }
                }
                still_looping = backward_stream_chunk(&stream);
            }while(still_looping);
            double_break2:;
        }
    }
    else{
        pos = 0;
    }
    
    return(pos);
}

//
// Boundary Type Seeks
//

static int32_t
buffer_seek_alphanumeric_right(Application_Links *app, Buffer_Summary *buffer, int32_t pos){
    char data_chunk[1024];
    Stream_Chunk stream = {0};
    
    if (init_stream_chunk(&stream, app, buffer, pos, data_chunk, sizeof(data_chunk))){
        
        bool32 still_looping = true;
        do{
            for (; pos < stream.end; ++pos){
                if (char_is_alpha_numeric_true_utf8(stream.data[pos])){
                    goto double_break1;
                }
            }
            still_looping = forward_stream_chunk(&stream);
        }while(still_looping);
        double_break1:;
        
        still_looping = true;
        do{
            for (; pos < stream.end; ++pos){
                if (!char_is_alpha_numeric_true_utf8(stream.data[pos])){
                    goto double_break2;
                }
            }
            still_looping = forward_stream_chunk(&stream);
        }while(still_looping);
        double_break2:;
    }
    
    return(pos);
}

static int32_t
buffer_seek_alphanumeric_left(Application_Links *app, Buffer_Summary *buffer, int32_t pos){
    char data_chunk[1024];
    Stream_Chunk stream = {0};
    
    --pos;
    if (pos > 0){
        if (init_stream_chunk(&stream, app, buffer, pos, data_chunk, sizeof(data_chunk))){
            bool32 still_looping = true;
            do{
                for (; pos >= stream.start; --pos){
                    if (char_is_alpha_numeric_true_utf8(stream.data[pos])){
                        goto double_break1;
                    }
                }
                still_looping = backward_stream_chunk(&stream);
            }while(still_looping);
            double_break1:;
            
            still_looping = true;
            do{
                for (; pos >= stream.start; --pos){
                    if (!char_is_alpha_numeric_true_utf8(stream.data[pos])){
                        ++pos;
                        goto double_break2;
                    }
                }
                still_looping = backward_stream_chunk(&stream);
            }while(still_looping);
            double_break2:;
        }
    }
    else{
        pos = 0;
    }
    
    return(pos);
}

static int32_t
buffer_seek_alphanumeric_or_underscore_right(Application_Links *app, Buffer_Summary *buffer, int32_t pos){
    char data_chunk[1024];
    Stream_Chunk stream = {0};
    
    if (init_stream_chunk(&stream, app, buffer, pos, data_chunk, sizeof(data_chunk))){
        bool32 still_looping = true;
        do{
            for (; pos < stream.end; ++pos){
                if (char_is_alpha_numeric_utf8(stream.data[pos])){
                    goto double_break1;
                }
            }
            still_looping = forward_stream_chunk(&stream);
        }while(still_looping);
        double_break1:;
        
        still_looping = true;
        do{
            for (; pos < stream.end; ++pos){
                if (!char_is_alpha_numeric_utf8(stream.data[pos])){
                    goto double_break2;
                }
            }
            still_looping = forward_stream_chunk(&stream);
        }while(still_looping);
        double_break2:;
    }
    
    return(pos);
}

static int32_t
buffer_seek_alphanumeric_or_underscore_left(Application_Links *app, Buffer_Summary *buffer, int32_t pos){
    char data_chunk[1024];
    Stream_Chunk stream = {0};
    
    --pos;
    if (pos > 0){
        if (init_stream_chunk(&stream, app, buffer, pos, data_chunk, sizeof(data_chunk))){
            
            bool32 still_looping = true;
            do{
                for (; pos >= stream.start; --pos){
                    if (char_is_alpha_numeric_utf8(stream.data[pos])){
                        goto double_break1;
                    }
                }
                still_looping = backward_stream_chunk(&stream);
            }while(still_looping);
            double_break1:;
            
            still_looping = true;
            do{
                for (; pos >= stream.start; --pos){
                    if (!char_is_alpha_numeric_utf8(stream.data[pos])){
                        ++pos;
                        goto double_break2;
                    }
                }
                still_looping = backward_stream_chunk(&stream);
            }while(still_looping);
            double_break2:;
        }
    }
    else{
        pos = 0;
    }
    
    return(pos);
}

static int32_t
buffer_seek_range_camel_right(Application_Links *app, Buffer_Summary *buffer, int32_t pos, int32_t an_pos){
    char data_chunk[1024];
    Stream_Chunk stream = {0};
    
    ++pos;
    if (pos < an_pos){
        stream.max_end = an_pos;
        if (init_stream_chunk(&stream, app, buffer, pos, data_chunk, sizeof(data_chunk))){
            
            uint8_t c = 0, pc = stream.data[pos];
            ++pos;
            
            bool32 still_looping = false;
            do{
                for (; pos < stream.end; ++pos){
                    c = stream.data[pos];
                    if (char_is_upper(c) && char_is_lower_utf8(pc)){
                        goto double_break1;
                    }
                    pc = c;
                }
                still_looping = forward_stream_chunk(&stream);
            }while(still_looping);
            double_break1:;
        }
    }
    else{
        pos = an_pos;
    }
    
    return(pos);
}

static int32_t
buffer_seek_range_camel_left(Application_Links *app, Buffer_Summary *buffer, int32_t pos, int32_t an_pos){
    char data_chunk[1024];
    Stream_Chunk stream = {0};
    
    --pos;
    if (pos > 0){
        stream.min_start = an_pos+1;
        if (init_stream_chunk(&stream, app, buffer, pos, data_chunk, sizeof(data_chunk))){
            
            char c = 0, pc = stream.data[pos];
            
            bool32 still_looping = false;
            do{
                for (; pos >= stream.start; --pos){
                    c = stream.data[pos];
                    if (char_is_upper(c) && char_is_lower_utf8(pc)){
                        goto double_break1;
                    }
                    pc = c;
                }
                still_looping = backward_stream_chunk(&stream);
            }while(still_looping);
            double_break1:;
        }
    }
    else{
        pos = 0;
    }
    
    return(pos);
}

static int32_t
buffer_seek_alphanumeric_or_camel_right(Application_Links *app, Buffer_Summary *buffer, int32_t pos){
    int32_t an_pos = buffer_seek_alphanumeric_right(app, buffer, pos);
    int32_t result = buffer_seek_range_camel_right(app, buffer, pos, an_pos);
    return(result);
}

static int32_t
buffer_seek_alphanumeric_or_camel_left(Application_Links *app, Buffer_Summary *buffer, int32_t pos){
    int32_t an_pos = buffer_seek_alphanumeric_left(app, buffer, pos);
    int32_t result = buffer_seek_range_camel_left(app, buffer, pos, an_pos);
    return(result);
}

static int32_t
seek_token_left(Cpp_Token_Array *tokens, int32_t pos){
    Cpp_Get_Token_Result get = cpp_get_token(*tokens, pos);
    if (get.token_index == -1){
        get.token_index = 0;
    }
    
    Cpp_Token *token = tokens->tokens + get.token_index;
    if (token->start == pos && get.token_index > 0){
        --token;
    }
    
    return(token->start);
}

static int32_t
seek_token_right(Cpp_Token_Array *tokens, int32_t pos){
    Cpp_Get_Token_Result get = cpp_get_token(*tokens, pos);
    if (get.in_whitespace){
        ++get.token_index;
    }
    if (get.token_index >= tokens->count){
        get.token_index = tokens->count-1;
    }
    
    Cpp_Token *token = tokens->tokens + get.token_index;
    return(token->start + token->size);
}

static Cpp_Token_Array
buffer_get_all_tokens(Application_Links *app, Partition *part, Buffer_Summary *buffer){
    Cpp_Token_Array array = {0};
    
    if (buffer->exists && buffer->is_lexed){
        array.count = buffer_token_count(app, buffer);
        array.max_count = array.count;
        array.tokens = push_array(part, Cpp_Token, array.count);
        buffer_read_tokens(app, buffer, 0, array.count, array.tokens);
    }
    
    return(array);
}

static int32_t
buffer_boundary_seek(Application_Links *app, Buffer_Summary *buffer, Partition *part, int32_t start_pos, bool32 seek_forward, Seek_Boundary_Flag flags)/*
DOC_PARAM(buffer, The buffer parameter specifies the buffer through which to seek.)
DOC_PARAM(start_pos, The beginning position of the seek is specified by start_pos measured in absolute position.)
DOC_PARAM(seek_forward, If this parameter is non-zero it indicates that the seek should move foward through the buffer.)
DOC_PARAM(flags, This field specifies the types of boundaries at which the seek should stop.)

DOC_RETURN(This call returns the absolute position where the seek stopped.
If the seek goes below 0 the returned value is -1.
If the seek goes past the end the returned value is the size of the buffer.)

DOC_SEE(Seek_Boundary_Flag)
DOC_SEE(4coder_Buffer_Positioning_System)
*/{
    int32_t result = 0;
    
    // TODO(allen): reduce duplication?
    Temp_Memory temp = begin_temp_memory(part);
    if (buffer->exists){
        int32_t pos[4];
        int32_t size = buffer->size;
        int32_t new_pos = 0;
        
        if (start_pos < 0){
            start_pos = 0;
        }
        else if (start_pos > size){
            start_pos = size;
        }
        
        if (seek_forward){
            for (int32_t i = 0; i < ArrayCount(pos); ++i){
                pos[i] = size;
            }
            
            if (flags & BoundaryWhitespace){
                pos[0] = buffer_seek_whitespace_right(app, buffer, start_pos);
            }
            
            if (flags & BoundaryToken){
                if (buffer->tokens_are_ready){
                    Cpp_Token_Array array = buffer_get_all_tokens(app, part, buffer);
                    pos[1] = seek_token_right(&array, start_pos);
                }
                else{
                    pos[1] = buffer_seek_whitespace_right(app, buffer, start_pos);
                }
            }
            
            if (flags & BoundaryAlphanumeric){
                pos[2] = buffer_seek_alphanumeric_right(app, buffer, start_pos);
                if (flags & BoundaryCamelCase){
                    pos[3] = buffer_seek_range_camel_right(app, buffer, start_pos, pos[2]);
                }
            }
            else{
                if (flags & BoundaryCamelCase){
                    pos[3] = buffer_seek_alphanumeric_or_camel_right(app, buffer, start_pos);
                }
            }
            
            new_pos = size;
            for (int32_t i = 0; i < ArrayCount(pos); ++i){
                if (pos[i] < new_pos){
                    new_pos = pos[i];
                }
            }
        }
        else{
            for (int32_t i = 0; i < ArrayCount(pos); ++i){
                pos[i] = 0;
            }
            
            if (flags & BoundaryWhitespace){
                pos[0] = buffer_seek_whitespace_left(app, buffer, start_pos);
            }
            
            if (flags & BoundaryToken){
                if (buffer->tokens_are_ready){
                    Cpp_Token_Array array = buffer_get_all_tokens(app, part, buffer);
                    pos[1] = seek_token_left(&array, start_pos);
                }
                else{
                    pos[1] = buffer_seek_whitespace_left(app, buffer, start_pos);
                }
            }
            
            if (flags & BoundaryAlphanumeric){
                pos[2] = buffer_seek_alphanumeric_left(app, buffer, start_pos);
                if (flags & BoundaryCamelCase){
                    pos[3] = buffer_seek_range_camel_left(app, buffer, start_pos, pos[2]);
                }
            }
            else{
                if (flags & BoundaryCamelCase){
                    pos[3] = buffer_seek_alphanumeric_or_camel_left(app, buffer, start_pos);
                }
            }
            
            new_pos = 0;
            for (int32_t i = 0; i < ArrayCount(pos); ++i){
                if (pos[i] > new_pos){
                    new_pos = pos[i];
                }
            }
        }
        result = new_pos;
    }
    end_temp_memory(temp);
    
    return(result);
}

//
// Character Seeks
//

void
buffer_seek_delimiter_forward(Application_Links *app, Buffer_Summary *buffer, int32_t pos, char delim, int32_t *result){
    if (buffer->exists){
        char chunk[1024];
        int32_t size = sizeof(chunk);
        Stream_Chunk stream = {0};
        
        if (init_stream_chunk(&stream, app, buffer, pos, chunk, size)){
            int32_t still_looping = 1;
            do{
                for(; pos < stream.end; ++pos){
                    char at_pos = stream.data[pos];
                    if (at_pos == delim){
                        *result = pos;
                        goto finished;
                    }
                }
                still_looping = forward_stream_chunk(&stream);
            }while (still_looping);
        }
    }
    
    *result = buffer->size;
    
    finished:;
}

static void
buffer_seek_delimiter_backward(Application_Links *app, Buffer_Summary *buffer, int32_t pos, char delim, int32_t *result){
    if (buffer->exists){
        char chunk[1024];
        int32_t size = sizeof(chunk);
        Stream_Chunk stream = {0};
        
        if (init_stream_chunk(&stream, app, buffer, pos, chunk, size)){
            int32_t still_looping = 1;
            do{
                for(; pos >= stream.start; --pos){
                    char at_pos = stream.data[pos];
                    if (at_pos == delim){
                        *result = pos;
                        goto finished;
                    }
                }
                still_looping = backward_stream_chunk(&stream);
            }while (still_looping);
        }
    }
    
    *result = 0;
    
    finished:;
}

//
// Buffer Substring Seeks
//

// TODO(allen): This duplication is driving me crazy... I've gotta
// upgrade the meta programming system another level.

// NOTE(allen): This is limitted to a string size of 512.
// You can push it up or do something more clever by just
// replacing char read_buffer[512]; with more memory.
static void
buffer_seek_string_forward(Application_Links *app, Buffer_Summary *buffer, int32_t pos, int32_t end, char *str, int32_t size, int32_t *result){
    char read_buffer[512];
    
    if (buffer->size > end){
        *result = buffer->size;
    }
    else{
        *result = end;
    }
    
    if (size > 0 && size <= sizeof(read_buffer)){
        if (buffer->exists){
            String read_str = make_fixed_width_string(read_buffer);
            String needle_str = make_string(str, size);
            char first_char = str[0];
            
            read_str.size = size;
            
            char chunk[1024];
            Stream_Chunk stream = {0};
            stream.max_end = end;
            
            if (init_stream_chunk(&stream, app, buffer, pos, chunk, sizeof(chunk))){
                int32_t still_looping = 1;
                do{
                    for(; pos < stream.end; ++pos){
                        char at_pos = stream.data[pos];
                        if (at_pos == first_char){
                            buffer_read_range(app, buffer, pos, pos+size, read_buffer);
                            if (match_ss(needle_str, read_str)){
                                *result = pos;
                                goto finished;
                            }
                        }
                    }
                    still_looping = forward_stream_chunk(&stream);
                }while (still_looping);
            }
        }
        
        if (end == 0){
            *result = buffer->size;
        }
        else{
            *result = end;
        }
        
        finished:;
    }
}

// NOTE(allen): This is limitted to a string size of 512.
// You can push it up or do something more clever by just
// replacing char read_buffer[512]; with more memory.
static void
buffer_seek_string_backward(Application_Links *app, Buffer_Summary *buffer, int32_t pos, int32_t min, char *str, int32_t size, int32_t *result){
    char read_buffer[512];
    
    *result = min-1;
    if (size > 0 && size <= sizeof(read_buffer)){
        if (buffer->exists){
            String read_str = make_fixed_width_string(read_buffer);
            String needle_str = make_string(str, size);
            char first_char = str[0];
            
            read_str.size = size;
            
            char chunk[1024];
            Stream_Chunk stream = {0};
            stream.min_start = min;
            
            if (init_stream_chunk(&stream, app, buffer, pos, chunk, sizeof(chunk))){
                int32_t still_looping = 1;
                do{
                    for(; pos >= stream.start; --pos){
                        char at_pos = stream.data[pos];
                        if (at_pos == first_char){
                            buffer_read_range(app, buffer, pos, pos+size, read_buffer);
                            if (match_ss(needle_str, read_str)){
                                *result = pos;
                                goto finished;
                            }
                        }
                    }
                    still_looping = backward_stream_chunk(&stream);
                }while (still_looping);
            }
        }
        
        finished:;
    }
}

// NOTE(allen): This is limitted to a string size of 512.
// You can push it up or do something more clever by just
// replacing char read_buffer[512]; with more memory.
static void
buffer_seek_string_insensitive_forward(Application_Links *app, Buffer_Summary *buffer, int32_t pos, int32_t end, char *str, int32_t size, int32_t *result){
    char read_buffer[512];
    char chunk[1024];
    int32_t chunk_size = sizeof(chunk);
    Stream_Chunk stream = {0};
    stream.max_end = end;
    
    if (buffer->size > end){
        *result = buffer->size;
    }
    else{
        *result = end;
    }
    
    if (size > 0 && size <= sizeof(read_buffer)){
        if (buffer->exists){
            String read_str = make_fixed_width_string(read_buffer);
            String needle_str = make_string(str, size);
            char first_char = char_to_upper(str[0]);
            
            read_str.size = size;
            
            if (init_stream_chunk(&stream, app, buffer, pos, chunk, chunk_size)){
                int32_t still_looping = 1;
                do{
                    for(; pos < stream.end; ++pos){
                        char at_pos = char_to_upper(stream.data[pos]);
                        if (at_pos == first_char){
                            buffer_read_range(app, buffer, pos, pos+size, read_buffer);
                            if (match_insensitive_ss(needle_str, read_str)){
                                *result = pos;
                                goto finished;
                            }
                        }
                    }
                    still_looping = forward_stream_chunk(&stream);
                }while (still_looping);
            }
        }
        
        finished:;
    }
}

// NOTE(allen): This is limitted to a string size of 512.
// You can push it up or do something more clever by just
// replacing char read_buffer[512]; with more memory.
static void
buffer_seek_string_insensitive_backward(Application_Links *app, Buffer_Summary *buffer, int32_t pos, int32_t min, char *str, int32_t size, int32_t *result){
    char read_buffer[512];
    char chunk[1024];
    int32_t chunk_size = sizeof(chunk);
    Stream_Chunk stream = {0};
    stream.min_start = min;
    
    *result = min-1;
    if (size > 0 && size <= sizeof(read_buffer)){
        if (buffer->exists){
            String read_str = make_fixed_width_string(read_buffer);
            String needle_str = make_string(str, size);
            char first_char = char_to_upper(str[0]);
            
            read_str.size = size;
            
            if (init_stream_chunk(&stream, app, buffer, pos, chunk, chunk_size)){
                int32_t still_looping = 1;
                do{
                    for(; pos >= stream.start; --pos){
                        char at_pos = char_to_upper(stream.data[pos]);
                        if (at_pos == first_char){
                            buffer_read_range(app, buffer, pos, pos+size, read_buffer);
                            if (match_insensitive_ss(needle_str, read_str)){
                                *result = pos;
                                goto finished;
                            }
                        }
                    }
                    still_looping = backward_stream_chunk(&stream);
                }while (still_looping);
            }
        }
        
        finished:;
    }
}


//
// Buffer Line Positioning
//

static bool32
read_line(Application_Links *app, Partition *part, Buffer_Summary *buffer, int32_t line, String *str){
    Partial_Cursor begin = {0};
    Partial_Cursor end = {0};
    
    bool32 success = false;
    
    if (buffer_compute_cursor(app, buffer, seek_line_char(line, 1), &begin)){
        if (buffer_compute_cursor(app, buffer, seek_line_char(line, -1), &end)){
            if (begin.line == line){
                if (0 <= begin.pos && begin.pos <= end.pos && end.pos <= buffer->size){
                    int32_t size = (end.pos - begin.pos);
                    *str = make_string(push_array(part, char, size+1), size+1);
                    if (str->str){
                        success = true;
                        buffer_read_range(app, buffer, begin.pos, end.pos, str->str);
                        str->size = size;
                        terminate_with_null(str);
                    }
                }
            }
        }
    }
    
    return(success);
}

static int32_t
buffer_get_line_start(Application_Links *app, Buffer_Summary *buffer, int32_t line){
    Partial_Cursor partial_cursor;
    int32_t result = buffer->size;
    if (line <= buffer->line_count){
        buffer_compute_cursor(app, buffer, seek_line_char(line, 1), &partial_cursor);
        result = partial_cursor.pos;
    }
    return(result);
}

static int32_t
buffer_get_line_end(Application_Links *app, Buffer_Summary *buffer, int32_t line){
    Partial_Cursor partial_cursor;
    int32_t result = buffer->size;
    if (line <= buffer->line_count){
        buffer_compute_cursor(app, buffer, seek_line_char(line, -1), &partial_cursor);
        result = partial_cursor.pos;
    }
    return(result);
}

static bool32
buffer_line_is_blank(Application_Links *app, Buffer_Summary *buffer, int32_t line){
    Partial_Cursor start, end;
    bool32 result = 0;
    if (line <= buffer->line_count){
        buffer_compute_cursor(app, buffer, seek_line_char(line, 1), &start);
        buffer_compute_cursor(app, buffer, seek_line_char(line, -1), &end);
        
        static const int32_t chunk_size = 1024;
        char chunk[chunk_size];
        Stream_Chunk stream = {0};
        int32_t i = start.pos;
        stream.max_end = end.pos;
        
        result = true;
        if (init_stream_chunk(&stream, app, buffer, i, chunk, chunk_size)){
            bool32 still_looping = false;
            do{
                for (;i < stream.end; ++i){
                    char c = stream.data[i];
                    if (!(c == ' ' || c == '\t' || c == '\r' || c == '\v' || c == '\n')){
                        result = false;
                        goto double_break;
                    }
                }
                still_looping = forward_stream_chunk(&stream);
            }while(still_looping);
        }
        double_break:;
    }
    return(result);
}

static int32_t
buffer_get_line_index(Application_Links *app, Buffer_Summary *buffer, int32_t pos){
    Partial_Cursor partial_cursor;
    buffer_compute_cursor(app, buffer, seek_pos(pos), &partial_cursor);
    return(partial_cursor.line);
}

static Cpp_Token*
get_first_token_at_line(Application_Links *app, Buffer_Summary *buffer, Cpp_Token_Array tokens, int32_t line, int32_t *line_start_out = 0){
    int32_t line_start = buffer_get_line_start(app, buffer, line);
    Cpp_Get_Token_Result get_token = cpp_get_token(tokens, line_start);
    
    if (get_token.in_whitespace){
        get_token.token_index += 1;
    }
    
    if (line_start_out){
        *line_start_out = line_start;
    }
    
    Cpp_Token *result = 0;
    if (get_token.token_index < tokens.count){
        result = tokens.tokens + get_token.token_index;
    }
    
    return(result);
}

static String
read_identifier_at_pos(Application_Links *app, Buffer_Summary *buffer, int32_t pos, char *space, int32_t max, Range *range_out){
    String query = {0};
    
    int32_t start = buffer_seek_alphanumeric_or_underscore_left(app, buffer, pos);
    int32_t end = buffer_seek_alphanumeric_or_underscore_right(app, buffer, start);
    
    if (!(start <= pos && pos < end)){
        end = buffer_seek_alphanumeric_or_underscore_right(app, buffer, pos);
        start = buffer_seek_alphanumeric_or_underscore_left(app, buffer, end);
    }
    
    if (start <= pos && pos < end){
        int32_t size = end - start;
        if (size <= max){
            if (range_out != 0){
                *range_out = make_range(start, end);
            }
            buffer_read_range(app, buffer, start, end, space);
            query = make_string_cap(space, size, max);
        }
    }
    
    return(query);
}

#endif

// BOTTOM