#include "strstream.h"

#include <string.h>
#include <stdlib.h>
#include <limits.h>
#include <stdarg.h>
#include <stdio.h>
#include <math.h> // HUGE_VALF
#include "tracelog.h"

/* == INPUT STREAM ============================================ */

str_istream_t istrInit(const char *str) {
    return istrInitLen(str, strlen(str));
}

str_istream_t istrInitLen(const char *str, size_t len) {
    str_istream_t res;
    res.start = res.cur = str;
    res.size = len;
    return res;
}

char istrGet(str_istream_t *ctx) {
    return *ctx->cur++;
}

void istrIgnore(str_istream_t *ctx, char delim) {
    size_t position = ctx->cur - ctx->start;
    size_t i;
    for(i = position; 
        i < ctx->size && *ctx->cur != delim; 
        ++i, ++ctx->cur);
}

char istrPeek(str_istream_t *ctx) {
    return *ctx->cur;
}

void istrSkip(str_istream_t *ctx, size_t n) {
    size_t remaining = ctx->size - (ctx->cur - ctx->start);
    if(n > remaining) {
        warn("skipping more then remaining: %zu -> %zu", n, remaining);
        return;
    }
    ctx->cur += n;
}

void istrRead(str_istream_t *ctx, char *buf, size_t len) {
    size_t remaining = ctx->size - (ctx->cur - ctx->start);
    if(len > remaining) {
        warn("istrRead: trying to read len %zu from remaining %zu", len, remaining);
        return;
    }
    memcpy(buf, ctx->cur, len);
    ctx->cur += len;
}

size_t istrReadMax(str_istream_t *ctx, char *buf, size_t len) {
    size_t remaining = ctx->size - (ctx->cur - ctx->start);
    len = remaining < len ? remaining : len;
    memcpy(buf, ctx->cur, len);
    ctx->cur += len;
    return len;
}

void istrRewind(str_istream_t *ctx) {
    ctx->cur = ctx->start;
}

size_t istrTell(str_istream_t *ctx) {
    return ctx->cur - ctx->start;
}

bool istrIsFinished(str_istream_t *ctx) {
    return ctx->cur == (ctx->start + ctx->size + 1);
}

bool istrGetbool(str_istream_t *ctx, bool *val) {
    size_t remaining = ctx->size - (ctx->cur - ctx->start);
    if(strncmp(ctx->cur, "true", remaining) == 0) {
        *val = true;
        return true;
    }
    if(strncmp(ctx->cur, "false", remaining) == 0) {
        *val = false;
        return true;
    }
    return false;
}

bool istrGetu8(str_istream_t *ctx, uint8_t *val) {
    char *end = NULL;
    *val = (uint8_t) strtoul(ctx->cur, &end, 0);
    
    if(ctx->cur == end) {
        warn("istrGetu8: no valid conversion could be performed");
        return false;
    }
    else if(*val == UINT8_MAX) {
        warn("istrGetu8: value read is out of the range of representable values");
        return false;
    }

    ctx->cur = end;
    return true;
}

bool istrGetu16(str_istream_t *ctx, uint16_t *val) {
    char *end = NULL;
    *val = (uint16_t) strtoul(ctx->cur, &end, 0);
    
    if(ctx->cur == end) {
        warn("istrGetu16: no valid conversion could be performed");
        return false;
    }
    else if(*val == UINT16_MAX) {
        warn("istrGetu16: value read is out of the range of representable values");
        return false;
    }
    
    ctx->cur = end;
    return true;
}

bool istrGetu32(str_istream_t *ctx, uint32_t *val) {
    char *end = NULL;
    *val = (uint32_t) strtoul(ctx->cur, &end, 0);
    
    if(ctx->cur == end) {
        warn("istrGetu32: no valid conversion could be performed");
        return false;
    }
    else if(*val == UINT32_MAX) {
        warn("istrGetu32: value read is out of the range of representable values");
        return false;
    }
    
    ctx->cur = end;
    return true;
}

bool istrGetu64(str_istream_t *ctx, uint64_t *val) {
    char *end = NULL;
    *val = strtoull(ctx->cur, &end, 0);
    
    if(ctx->cur == end) {
        warn("istrGetu64: no valid conversion could be performed");
        return false;
    }
    else if(*val == ULLONG_MAX) {
        warn("istrGetu64: value read is out of the range of representable values");
        return false;
    }

    ctx->cur = end;
    return true;
}

bool istrGeti8(str_istream_t *ctx, int8_t *val) {
    char *end = NULL;
    *val = (int8_t) strtol(ctx->cur, &end, 0);
    
    if(ctx->cur == end) {
        warn("istrGeti8: no valid conversion could be performed");
        return false;
    }
    else if(*val == INT8_MAX || *val == INT8_MIN) {
        warn("istrGeti8: value read is out of the range of representable values");
        return false;
    }

    ctx->cur = end;
    return true;
}

bool istrGeti16(str_istream_t *ctx, int16_t *val) {
    char *end = NULL;
    *val = (int16_t) strtol(ctx->cur, &end, 0);
    
    if(ctx->cur == end) {
        warn("istrGeti16: no valid conversion could be performed");
        return false;
    }
    else if(*val == INT16_MAX || *val == INT16_MIN) {
        warn("istrGeti16: value read is out of the range of representable values");
        return false;
    }

    ctx->cur = end;
    return true;
}

bool istrGeti32(str_istream_t *ctx, int32_t *val) {
    char *end = NULL;
    *val = (int32_t) strtol(ctx->cur, &end, 0);
    
    if(ctx->cur == end) {
        warn("istrGeti32: no valid conversion could be performed");
        return false;
    }
    else if(*val == INT32_MAX || *val == INT32_MIN) {
        warn("istrGeti32: value read is out of the range of representable values");
        return false;
    }

    ctx->cur = end;
    return true;
}

bool istrGeti64(str_istream_t *ctx, int64_t *val) {
    char *end = NULL;
    *val = strtoll(ctx->cur, &end, 0);
    
    if(ctx->cur == end) {
        warn("istrGeti64: no valid conversion could be performed");
        return false;
    }
    else if(*val == INT64_MAX || *val == INT64_MIN) {
        warn("istrGeti64: value read is out of the range of representable values");
        return false;
    }

    ctx->cur = end;
    return true;
}

bool istrGetfloat(str_istream_t *ctx, float *val) {
    char *end = NULL;
    *val = strtof(ctx->cur, &end);
    
    if(ctx->cur == end) {
        warn("istrGetfloat: no valid conversion could be performed");
        return false;
    }
    else if(*val == HUGE_VALF || *val == -HUGE_VALF) {
        warn("istrGetfloat: value read is out of the range of representable values");
        return false;
    }

    ctx->cur = end;
    return true;
}

bool istrGetdouble(str_istream_t *ctx, double *val) {
    char *end = NULL;
    *val = strtod(ctx->cur, &end);
    
    if(ctx->cur == end) {
        warn("istrGetdouble: no valid conversion could be performed");
        return false;
    }
    else if(*val == HUGE_VAL || *val == -HUGE_VAL) {
        warn("istrGetdouble: value read is out of the range of representable values");
        return false;
    }

    ctx->cur = end;
    return true;
}

size_t istrGetstring(str_istream_t *ctx, char **val, char delim) {
    const char *from = ctx->cur;
    istrIgnore(ctx, delim);
    // if it didn't actually find it, it just reached the end of the string
    if(*ctx->cur != delim) {
        *val = NULL;
        return 0;
    }
    size_t len = ctx->cur - from;
    *val = malloc(len + 1);
    memcpy(*val, from, len);
    (*val)[len] = '\0';
    return len;
}

size_t istrGetstringBuf(str_istream_t *ctx, char *val, size_t len) {
    size_t remaining = ctx->size - (ctx->cur - ctx->start);
    len -= 1;
    len = remaining < len ? remaining : len;
    memcpy(val, ctx->cur, len);
    val[len] = '\0';
    ctx->cur += len;
    return len;
}

strview_t istrGetview(str_istream_t *ctx, char delim) {
    const char *from = ctx->cur;
    istrIgnore(ctx, delim);
    // if it didn't actually find it, it just reached the end of the string
    if(*ctx->cur != delim) {
        return strvInitLen(NULL, 0);
    }
    size_t len = ctx->cur - from;
    return strvInitLen(from, len);
}

strview_t istrGetviewLen(str_istream_t *ctx, size_t off, size_t len) {
    size_t remaining = ctx->size - (ctx->cur - ctx->start) - off;
    if(len > remaining) len = remaining;
    return strvInitLen(ctx->cur + off, len);
}

/* == OUTPUT STREAM =========================================== */

static void _ostrRealloc(str_ostream_t *ctx, size_t atlest) {
    ctx->allocated = (ctx->allocated * 2) + atlest;
    ctx->buf = realloc(ctx->buf, ctx->allocated);
}

str_ostream_t ostrInit() {
    return ostrInitLen(1);
}

str_ostream_t ostrInitLen(size_t initial_alloc) {
    str_ostream_t stream;
    stream.buf = calloc(initial_alloc, 1);
    stream.size = 0;
    stream.allocated = initial_alloc;
    return stream;
}

str_ostream_t ostrInitStr(const char *cstr, size_t len) {
    str_ostream_t stream;
    stream.buf = malloc(len + 1);
    memcpy(stream.buf, cstr, len);
    return stream;
}

char ostrBack(str_ostream_t *ctx) {
    return ctx->buf[ctx->size - 1];
}

void ostrFree(str_ostream_t *ctx) {
    free(ctx->buf);
    ctx->size = 0;
    ctx->allocated = 0;
}

size_t ostrMove(str_ostream_t *ctx, char **str) {
    *str = ctx->buf;
    ctx->buf = NULL;
    size_t sz = ctx->size;
    ostrFree(ctx);
    return sz;
}

void ostrPrintf(str_ostream_t *ctx, const char *fmt, ...) {
    va_list va;
    va_start(va, fmt);

    // vsnprintf returns the length of the formatted string, even if truncated
    // we use this to get the actual length of the formatted string
    char buf[1];
    va_list vtemp;
    va_copy(vtemp, va);
    int len = vsnprintf(buf, sizeof(buf), fmt, vtemp);
    va_end(vtemp);
    if(len < 0) {
        err("couldn't format string \"%s\"", fmt);
        goto error;
    }

    size_t remaining = ctx->allocated - ctx->size;
    if(remaining < (size_t)len) {
        _ostrRealloc(ctx, len + 1);
        remaining = ctx->allocated - ctx->size;
    }

    // actual formatting here
    len = vsnprintf(ctx->buf + ctx->size, remaining, fmt, va);
    if(len < 0) {
        err("couldn't format stringh \"%s\"", fmt);
        goto error;
    }
    ctx->size += len;

error:
    va_end(va);
}

#define APPEND_BUF_LEN 20

void ostrPutc(str_ostream_t *ctx, char c) {
    if(ctx->size >= ctx->allocated) {
        _ostrRealloc(ctx, 1);
    }
    ctx->buf[ctx->size++] = c;
    ctx->buf[ctx->size] = '\0';
}

void ostrAppendbool(str_ostream_t *ctx, bool val) {
    ostrAppendview(ctx, strvInit(val ? "true" : "false"));
}

void ostrAppendu8(str_ostream_t *ctx, uint8_t val) {
    char buf[APPEND_BUF_LEN];
    int len = snprintf(buf, sizeof(buf), "%hhu", val);
    if(len <= 0) {
        err("ostrAppendu8: couldn't write %hhu", val);
        return;
    } 
    ostrAppendview(ctx, strvInitLen(buf, len));
}

void ostrAppendu16(str_ostream_t *ctx, uint16_t val) {
    char buf[APPEND_BUF_LEN];
    int len = snprintf(buf, sizeof(buf), "%hu", val);
    if(len <= 0) {
        err("ostrAppendu16: couldn't write %hu", val);
        return;
    } 
    ostrAppendview(ctx, strvInitLen(buf, len));
}

void ostrAppendu32(str_ostream_t *ctx, uint32_t val) {
    char buf[APPEND_BUF_LEN];
    int len = snprintf(buf, sizeof(buf), "%u", val);
    if(len <= 0) {
        err("ostrAppendu32: couldn't write %u", val);
        return;
    } 
    ostrAppendview(ctx, strvInitLen(buf, len));
}

void ostrAppendu64(str_ostream_t *ctx, uint64_t val) {
    char buf[APPEND_BUF_LEN];
#if _WIN32
    int len = snprintf(buf, sizeof(buf), "%llu", val);
#else
    int len = snprintf(buf, sizeof(buf), "%lu", val);
#endif
    if(len <= 0) {
        err("ostrAppendu64: couldn't write %lu", val);
        return;
    } 
    ostrAppendview(ctx, strvInitLen(buf, len));
}

void ostrAppendi8(str_ostream_t *ctx, int8_t val) {
    char buf[APPEND_BUF_LEN];
    int len = snprintf(buf, sizeof(buf), "%hhi", val);
    if(len <= 0) {
        err("ostrAppendi8: couldn't write %hhi", val);
        return;
    } 
    ostrAppendview(ctx, strvInitLen(buf, len));
}

void ostrAppendi16(str_ostream_t *ctx, int16_t val) {
    char buf[APPEND_BUF_LEN];
    int len = snprintf(buf, sizeof(buf), "%hi", val);
    if(len <= 0) {
        err("ostrAppendi16: couldn't write %hi", val);
        return;
    } 
    ostrAppendview(ctx, strvInitLen(buf, len));
}

void ostrAppendi32(str_ostream_t *ctx, int32_t val) {
    char buf[APPEND_BUF_LEN];
    int len = snprintf(buf, sizeof(buf), "%i", val);
    if(len <= 0) {
        err("ostrAppendi32: couldn't write %i", val);
        return;
    } 
    ostrAppendview(ctx, strvInitLen(buf, len));
}

void ostrAppendi64(str_ostream_t *ctx, int64_t val) {
    char buf[APPEND_BUF_LEN];
#if _WIN32
    int len = snprintf(buf, sizeof(buf), "%lli", val);
#else
    int len = snprintf(buf, sizeof(buf), "%li", val);
#endif
    if(len <= 0) {
        err("ostrAppendi64: couldn't write %li", val);
        return;
    } 
    ostrAppendview(ctx, strvInitLen(buf, len));
}

void ostrAppendfloat(str_ostream_t *ctx, float val) {
    char buf[APPEND_BUF_LEN * 3];
    int len = snprintf(buf, sizeof(buf), "%f", (double)val);
    if(len <= 0) {
        err("ostrAppendfloat: couldn't write %f", val);
        return;
    } 
    ostrAppendview(ctx, strvInitLen(buf, len));
}

void ostrAppenddouble(str_ostream_t *ctx, double val) {
    char buf[APPEND_BUF_LEN * 3];
    int len = snprintf(buf, sizeof(buf), "%f", val);
    if(len <= 0) {
        err("ostrAppenddouble: couldn't write %f", val);
        return;
    } 
    ostrAppendview(ctx, strvInitLen(buf, len));
}

void ostrAppendview(str_ostream_t *ctx, strview_t view) {
    if((ctx->allocated - ctx->size) < view.size) {
        _ostrRealloc(ctx, view.size + 1);
    }
    memcpy(ctx->buf + ctx->size, view.buf, view.size);
    ctx->size += view.size;
    ctx->buf[ctx->size] = '\0';
}