#define _XOPEN_SOURCE

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <strings.h>
#include <ctype.h>
#include <setjmp.h>
#include <stdarg.h>

#include "types.h"

uw_unit uw_unit_v = {};

#define ERROR_BUF_LEN 1024

typedef struct regions {
  struct regions *next;
} regions;

typedef struct {
  void (*func)(void*);
  void *arg;
} cleanup;

struct uw_context {
  char *headers, *headers_end;

  char *outHeaders, *outHeaders_front, *outHeaders_back;
  char *page, *page_front, *page_back;
  char *heap, *heap_front, *heap_back;
  char **inputs;

  void *db;

  jmp_buf jmp_buf;

  regions *regions;

  cleanup *cleanup, *cleanup_front, *cleanup_back;

  char error_message[ERROR_BUF_LEN];
};

extern int uw_inputs_len;

uw_context uw_init(size_t outHeaders_len, size_t page_len, size_t heap_len) {
  uw_context ctx = malloc(sizeof(struct uw_context));

  ctx->headers = ctx->headers_end = NULL;

  ctx->outHeaders_front = ctx->outHeaders = malloc(outHeaders_len);
  ctx->outHeaders_back = ctx->outHeaders_front + outHeaders_len;

  ctx->heap_front = ctx->heap = malloc(heap_len);

  ctx->page_front = ctx->page = malloc(page_len);
  ctx->page_back = ctx->page_front + page_len;

  ctx->heap_front = ctx->heap = malloc(heap_len);
  ctx->heap_back = ctx->heap_front + heap_len;

  ctx->inputs = calloc(uw_inputs_len, sizeof(char *));

  ctx->db = NULL;

  ctx->regions = NULL;

  ctx->cleanup_front = ctx->cleanup_back = ctx->cleanup = malloc(0);

  ctx->error_message[0] = 0;

  return ctx;
}

void uw_set_db(uw_context ctx, void *db) {
  ctx->db = db;
}

void *uw_get_db(uw_context ctx) {
  return ctx->db;
}

void uw_free(uw_context ctx) {
  free(ctx->outHeaders);
  free(ctx->page);
  free(ctx->heap);
  free(ctx->inputs);
  free(ctx->cleanup);
  free(ctx);
}

void uw_reset_keep_request(uw_context ctx) {
  ctx->outHeaders_front = ctx->outHeaders;
  ctx->page_front = ctx->page;
  ctx->heap_front = ctx->heap;
  ctx->regions = NULL;
  ctx->cleanup_front = ctx->cleanup;

  ctx->error_message[0] = 0;
}

void uw_reset_keep_error_message(uw_context ctx) {
  ctx->outHeaders_front = ctx->outHeaders;
  ctx->page_front = ctx->page;
  ctx->heap_front = ctx->heap;
  ctx->regions = NULL;
  ctx->cleanup_front = ctx->cleanup;
}

void uw_reset(uw_context ctx) {
  uw_reset_keep_request(ctx);
  memset(ctx->inputs, 0, uw_inputs_len * sizeof(char *));
}

void uw_db_init(uw_context);
void uw_handle(uw_context, char *);

failure_kind uw_begin_init(uw_context ctx) {
  int r = setjmp(ctx->jmp_buf);

  if (r == 0)
    uw_db_init(ctx);

  return r;
}

void uw_set_headers(uw_context ctx, char *headers) {
  char *s = headers, *s2;
  ctx->headers = headers;

  while (s2 = strchr(s, '\r')) {
    s = s2;

    if (s[1] == 0)
      break;

    *s = 0;
    s += 2;
  }

  ctx->headers_end = s;
}

failure_kind uw_begin(uw_context ctx, char *path) {
  int r = setjmp(ctx->jmp_buf);

  if (r == 0)
    uw_handle(ctx, path);

  return r;
}

__attribute__((noreturn)) void uw_error(uw_context ctx, failure_kind fk, const char *fmt, ...) {
  cleanup *cl;

  va_list ap;
  va_start(ap, fmt);

  vsnprintf(ctx->error_message, ERROR_BUF_LEN, fmt, ap);

  for (cl = ctx->cleanup; cl < ctx->cleanup_front; ++cl)
    cl->func(cl->arg);

  ctx->cleanup_front = ctx->cleanup;

  longjmp(ctx->jmp_buf, fk);
}

void uw_push_cleanup(uw_context ctx, void (*func)(void *), void *arg) {
  if (ctx->cleanup_front >= ctx->cleanup_back) {
    int len = ctx->cleanup_back - ctx->cleanup, newLen;
    if (len == 0)
      newLen = 1;
    else
      newLen = len * 2;
    ctx->cleanup = realloc(ctx->cleanup, newLen);
    ctx->cleanup_front = ctx->cleanup + len;
    ctx->cleanup_back = ctx->cleanup + newLen;
  }

  ctx->cleanup_front->func = func;
  ctx->cleanup_front->arg = arg;
  ++ctx->cleanup_front;
}

void uw_pop_cleanup(uw_context ctx) {
  if (ctx->cleanup_front == ctx->cleanup)
    uw_error(ctx, FATAL, "Attempt to pop from empty cleanup action stack");

  --ctx->cleanup_front;
  ctx->cleanup_front->func(ctx->cleanup_front->arg);
}

char *uw_error_message(uw_context ctx) {
  return ctx->error_message;
}

int uw_input_num(char*);

void uw_set_input(uw_context ctx, char *name, char *value) {
  int n = uw_input_num(name);

  if (n < 0)
    uw_error(ctx, FATAL, "Bad input name %s", name);

  if (n >= uw_inputs_len)
    uw_error(ctx, FATAL, "For input name %s, index %d is out of range", name, n);

  ctx->inputs[n] = value;

  //printf("[%d] %s = %s\n", n, name, value);
}

char *uw_get_input(uw_context ctx, int n) {
  if (n < 0)
    uw_error(ctx, FATAL, "Negative input index %d", n);
  if (n >= uw_inputs_len)
    uw_error(ctx, FATAL, "Out-of-bounds input index %d", n);
  //printf("[%d] = %s\n", n, ctx->inputs[n]);
  return ctx->inputs[n];
}

char *uw_get_optional_input(uw_context ctx, int n) {
  if (n < 0)
    uw_error(ctx, FATAL, "Negative input index %d", n);
  if (n >= uw_inputs_len)
    uw_error(ctx, FATAL, "Out-of-bounds input index %d", n);
  //printf("[%d] = %s\n", n, ctx->inputs[n]);
  return (ctx->inputs[n] == NULL ? "" : ctx->inputs[n]);
}

static void uw_check_heap(uw_context ctx, size_t extra) {
  if (ctx->heap_back - ctx->heap_front < extra) {
    size_t desired = ctx->heap_front - ctx->heap + extra, next;
    char *new_heap;

    next = ctx->heap_back - ctx->heap;
    if (next == 0)
      next = 1;
    for (; next < desired; next *= 2);

    new_heap = realloc(ctx->heap, next);
    ctx->heap_front = new_heap + (ctx->heap_front - ctx->heap);
    ctx->heap_back = new_heap + next;

    if (new_heap != ctx->heap) {
      ctx->heap = new_heap;
      uw_error(ctx, UNLIMITED_RETRY, "Couldn't allocate new heap chunk contiguously");
    }

    ctx->heap = new_heap;
  }
}

void *uw_malloc(uw_context ctx, size_t len) {
  void *result;

  uw_check_heap(ctx, len);

  result = ctx->heap_front;
  ctx->heap_front += len;
  return result;
}

void uw_begin_region(uw_context ctx) {
  regions *r = (regions *) ctx->heap_front;

  uw_check_heap(ctx, sizeof(regions));

  ctx->heap_front += sizeof(regions);

  r->next = ctx->regions;
  ctx->regions = r;
}

void uw_end_region(uw_context ctx) {
  regions *r = ctx->regions;

  if (r == NULL)
    uw_error(ctx, FATAL, "Region stack underflow");

  ctx->heap_front = (char *) r;
  ctx->regions = r->next;
}

void uw_memstats(uw_context ctx) {
  printf("Headers: %d/%d\n", ctx->outHeaders_front - ctx->outHeaders, ctx->outHeaders_back - ctx->outHeaders);
  printf("Page: %d/%d\n", ctx->page_front - ctx->page, ctx->page_back - ctx->page);
  printf("Heap: %d/%d\n", ctx->heap_front - ctx->heap, ctx->heap_back - ctx->heap);
}

int uw_really_send(int sock, const void *buf, size_t len) {
  while (len > 0) {
    size_t n = send(sock, buf, len, 0);

    if (n < 0)
      return n;

    buf += n;
    len -= n;
  }

  return 0;
}

int uw_send(uw_context ctx, int sock) {
  int n = uw_really_send(sock, ctx->outHeaders, ctx->outHeaders_front - ctx->outHeaders);

  if (n < 0)
    return n;

  n = uw_really_send(sock, "\r\n", 2);

  if (n < 0)
    return n;

  return uw_really_send(sock, ctx->page, ctx->page_front - ctx->page);
}

static void uw_check_headers(uw_context ctx, size_t extra) {
  size_t desired = ctx->outHeaders_front - ctx->outHeaders + extra, next;
  char *new_outHeaders;

  next = ctx->outHeaders_back - ctx->outHeaders;
  if (next < desired) {
    if (next == 0)
      next = 1;
    for (; next < desired; next *= 2);

    new_outHeaders = realloc(ctx->outHeaders, next);
    ctx->outHeaders_front = new_outHeaders + (ctx->outHeaders_front - ctx->outHeaders);
    ctx->outHeaders_back = new_outHeaders + next;
    ctx->outHeaders = new_outHeaders;
  }
}

void uw_write_header(uw_context ctx, uw_Basis_string s) {
  int len = strlen(s);

  uw_check_headers(ctx, len + 1);
  strcpy(ctx->outHeaders_front, s);
  ctx->outHeaders_front += len;
}

static void uw_check(uw_context ctx, size_t extra) {
  size_t desired = ctx->page_front - ctx->page + extra, next;
  char *new_page;

  next = ctx->page_back - ctx->page;
  if (next < desired) {
    if (next == 0)
      next = 1;
    for (; next < desired; next *= 2);

    new_page = realloc(ctx->page, next);
    ctx->page_front = new_page + (ctx->page_front - ctx->page);
    ctx->page_back = new_page + next;
    ctx->page = new_page;
  }
}

static void uw_writec_unsafe(uw_context ctx, char c) {
  *(ctx->page_front)++ = c;
}

void uw_writec(uw_context ctx, char c) {
  uw_check(ctx, 1);
  uw_writec_unsafe(ctx, c);
}

static void uw_write_unsafe(uw_context ctx, const char* s) {
  int len = strlen(s);
  memcpy(ctx->page_front, s, len);
  ctx->page_front += len;
}

void uw_write(uw_context ctx, const char* s) {
  uw_check(ctx, strlen(s) + 1);
  uw_write_unsafe(ctx, s);
  *ctx->page_front = 0;
}


char *uw_Basis_attrifyInt(uw_context ctx, uw_Basis_int n) {
  char *result;
  int len;
  uw_check_heap(ctx, INTS_MAX);
  result = ctx->heap_front;
  sprintf(result, "%lld%n", n, &len);
  ctx->heap_front += len+1;
  return result;
}

char *uw_Basis_attrifyFloat(uw_context ctx, uw_Basis_float n) {
  char *result;
  int len;
  uw_check_heap(ctx, FLOATS_MAX);
  result = ctx->heap_front;
  sprintf(result, "%g%n", n, &len);
  ctx->heap_front += len+1;
  return result;
}

char *uw_Basis_attrifyString(uw_context ctx, uw_Basis_string s) {
  int len = strlen(s);
  char *result, *p;
  uw_check_heap(ctx, len * 6 + 1);

  result = p = ctx->heap_front;

  for (; *s; s++) {
    char c = *s;

    if (c == '"') {
      strcpy(p, "&quot;");
      p += 6;
    } else if (c == '&') {
      strcpy(p, "&amp;");
      p += 5;
    }
    else if (isprint(c))
      *p++ = c;
    else {
      int len2;
      sprintf(p, "&#%d;%n", c, &len2);
      p += len2;
    }
  }

  *p++ = 0;
  ctx->heap_front = p;
  return result;
}

static void uw_Basis_attrifyInt_w_unsafe(uw_context ctx, uw_Basis_int n) {
  int len;

  sprintf(ctx->page_front, "%lld%n", n, &len);
  ctx->page_front += len;
}

uw_unit uw_Basis_attrifyInt_w(uw_context ctx, uw_Basis_int n) {
  uw_check(ctx, INTS_MAX);
  uw_Basis_attrifyInt_w_unsafe(ctx, n);

  return uw_unit_v;
}

uw_unit uw_Basis_attrifyFloat_w(uw_context ctx, uw_Basis_float n) {
  int len;

  uw_check(ctx, FLOATS_MAX);
  sprintf(ctx->page_front, "%g%n", n, &len);
  ctx->page_front += len;

  return uw_unit_v;
}

uw_unit uw_Basis_attrifyString_w(uw_context ctx, uw_Basis_string s) {
  uw_check(ctx, strlen(s) * 6);

  for (; *s; s++) {
    char c = *s;

    if (c == '"')
      uw_write_unsafe(ctx, "&quot;");
    else if (c == '&')
      uw_write_unsafe(ctx, "&amp;");
    else if (isprint(c))
      uw_writec_unsafe(ctx, c);
    else {
      uw_write_unsafe(ctx, "&#");
      uw_Basis_attrifyInt_w_unsafe(ctx, c);
      uw_writec_unsafe(ctx, ';');
    }
  }

  return uw_unit_v;
}


char *uw_Basis_urlifyInt(uw_context ctx, uw_Basis_int n) {
  int len;
  char *r;

  uw_check_heap(ctx, INTS_MAX);
  r = ctx->heap_front;
  sprintf(r, "%lld%n", n, &len);
  ctx->heap_front += len+1;
  return r;
}

char *uw_Basis_urlifyFloat(uw_context ctx, uw_Basis_float n) {
  int len;
  char *r;

  uw_check_heap(ctx, FLOATS_MAX);
  r = ctx->heap_front;
  sprintf(r, "%g%n", n, &len);
  ctx->heap_front += len+1;
  return r;
}

char *uw_Basis_urlifyString(uw_context ctx, uw_Basis_string s) {
  char *r, *p;

  uw_check_heap(ctx, strlen(s) * 3 + 1);

  for (r = p = ctx->heap_front; *s; s++) {
    char c = *s;

    if (c == ' ')
      *p++ = '+';
    else if (isalnum(c))
      *p++ = c;
    else {
      sprintf(p, "%%%02X", c);
      p += 3;
    }
  }

  *p++ = 0;
  ctx->heap_front = p;
  return r;
}

char *uw_Basis_urlifyBool(uw_context ctx, uw_Basis_bool b) {
  if (b == uw_Basis_False)
    return "0";
  else
    return "1";
}

static void uw_Basis_urlifyInt_w_unsafe(uw_context ctx, uw_Basis_int n) {
  int len;

  sprintf(ctx->page_front, "%lld%n", n, &len);
  ctx->page_front += len;
}

uw_unit uw_Basis_urlifyInt_w(uw_context ctx, uw_Basis_int n) {
  uw_check(ctx, INTS_MAX);
  uw_Basis_urlifyInt_w_unsafe(ctx, n);

  return uw_unit_v;
}

uw_unit uw_Basis_urlifyFloat_w(uw_context ctx, uw_Basis_float n) {
  int len;

  uw_check(ctx, FLOATS_MAX);
  sprintf(ctx->page_front, "%g%n", n, &len);
  ctx->page_front += len;

  return uw_unit_v;
}

uw_unit uw_Basis_urlifyString_w(uw_context ctx, uw_Basis_string s) {
  uw_check(ctx, strlen(s) * 3);

  for (; *s; s++) {
    char c = *s;

    if (c == ' ')
      uw_writec_unsafe(ctx, '+');
    else if (isalnum(c))
      uw_writec_unsafe(ctx, c);
    else {
      sprintf(ctx->page_front, "%%%02X", c);
      ctx->page_front += 3;
    }
  }

  return uw_unit_v;
}

uw_unit uw_Basis_urlifyBool_w(uw_context ctx, uw_Basis_bool b) {
  if (b == uw_Basis_False)
    uw_writec(ctx, '0');
  else
    uw_writec(ctx, '1');

  return uw_unit_v;
}


static char *uw_unurlify_advance(char *s) {
  char *new_s = strchr(s, '/');

  if (new_s)
    *new_s++ = 0;
  else
    new_s = strchr(s, 0);

  return new_s;
}

uw_Basis_int uw_Basis_unurlifyInt(uw_context ctx, char **s) {
  char *new_s = uw_unurlify_advance(*s);
  uw_Basis_int r;

  r = atoll(*s);
  *s = new_s;
  return r;
}

uw_Basis_float uw_Basis_unurlifyFloat(uw_context ctx, char **s) {
  char *new_s = uw_unurlify_advance(*s);
  uw_Basis_float r;

  r = atof(*s);
  *s = new_s;
  return r;
}

static uw_Basis_string uw_unurlifyString_to(uw_context ctx, char *r, char *s) {
  char *s1, *s2;
  int n;

  for (s1 = r, s2 = s; *s2; ++s1, ++s2) {
    char c = *s2;

    switch (c) {
    case '+':
      *s1 = ' ';
      break;
    case '%':
      if (s2[1] == 0)
        uw_error(ctx, FATAL, "Missing first character of escaped URL byte");
      if (s2[2] == 0)
        uw_error(ctx, FATAL, "Missing second character of escaped URL byte");
      if (sscanf(s2+1, "%02X", &n) != 1)
        uw_error(ctx, FATAL, "Invalid escaped URL byte starting at: %s", s2);
      *s1 = n;
      s2 += 2;
      break;
    default:
      *s1 = c;
    }
  }
  *s1++ = 0;
  return s1;
}

uw_Basis_bool uw_Basis_unurlifyBool(uw_context ctx, char **s) {
  char *new_s = uw_unurlify_advance(*s);
  uw_Basis_bool r;
  
  if (*s[0] == 0 || !strcmp(*s, "0") || !strcmp(*s, "off"))
    r = uw_Basis_False;
  else
    r = uw_Basis_True;

  *s = new_s;
  return r;
}

uw_Basis_string uw_Basis_unurlifyString(uw_context ctx, char **s) {
  char *new_s = uw_unurlify_advance(*s);
  char *r, *s1, *s2;
  int len, n;

  len = strlen(*s);
  uw_check_heap(ctx, len + 1);

  r = ctx->heap_front;
  ctx->heap_front = uw_unurlifyString_to(ctx, ctx->heap_front, *s);
  *s = new_s;
  return r;
}


char *uw_Basis_htmlifyInt(uw_context ctx, uw_Basis_int n) {
  int len;
  char *r;

  uw_check_heap(ctx, INTS_MAX);
  r = ctx->heap_front;
  sprintf(r, "%lld%n", n, &len);
  ctx->heap_front += len+1;
  return r;
}

uw_unit uw_Basis_htmlifyInt_w(uw_context ctx, uw_Basis_int n) {
  int len;

  uw_check(ctx, INTS_MAX);
  sprintf(ctx->page_front, "%lld%n", n, &len);
  ctx->page_front += len;
  
  return uw_unit_v;
}

char *uw_Basis_htmlifyFloat(uw_context ctx, uw_Basis_float n) {
  int len;
  char *r;

  uw_check_heap(ctx, FLOATS_MAX);
  r = ctx->heap_front;
  sprintf(r, "%g%n", n, &len);
  ctx->heap_front += len+1;
  return r;
}

uw_unit uw_Basis_htmlifyFloat_w(uw_context ctx, uw_Basis_float n) {
  int len;

  uw_check(ctx, FLOATS_MAX);
  sprintf(ctx->page_front, "%g%n", n, &len);
  ctx->page_front += len;

  return uw_unit_v;
}

char *uw_Basis_htmlifyString(uw_context ctx, uw_Basis_string s) {
  char *r, *s2;

  uw_check_heap(ctx, strlen(s) * 5 + 1);

  for (r = s2 = ctx->heap_front; *s; s++) {
    char c = *s;

    switch (c) {
    case '<':
      strcpy(s2, "&lt;");
      s2 += 4;
      break;
    case '&':
      strcpy(s2, "&amp;");
      s2 += 5;
      break;
    default:
      if (isprint(c))
        *s2++ = c;
      else {
        int len2;
        sprintf(s2, "&#%d;%n", c, &len2);
        s2 += len2;
      }
    }
  }

  *s2++ = 0;
  ctx->heap_front = s2;
  return r;
}

uw_unit uw_Basis_htmlifyString_w(uw_context ctx, uw_Basis_string s) {
  uw_check(ctx, strlen(s) * 6);

  for (; *s; s++) {
    char c = *s;

    switch (c) {
    case '<':
      uw_write_unsafe(ctx, "&lt;");
      break;
    case '&':
      uw_write_unsafe(ctx, "&amp;");
      break;
    default:
      if (isprint(c))
        uw_writec_unsafe(ctx, c);
      else {
        uw_write_unsafe(ctx, "&#");
        uw_Basis_attrifyInt_w_unsafe(ctx, c);
        uw_writec_unsafe(ctx, ';');
      }
    }
  }

  return uw_unit_v;
}

uw_Basis_string uw_Basis_htmlifyBool(uw_context ctx, uw_Basis_bool b) {
  if (b == uw_Basis_False)
    return "False";
  else
    return "True";
}

uw_unit uw_Basis_htmlifyBool_w(uw_context ctx, uw_Basis_bool b) {
  if (b == uw_Basis_False) {
    uw_check(ctx, 6);
    strcpy(ctx->page_front, "False");
    ctx->page_front += 5;
  } else {
    uw_check(ctx, 5);
    strcpy(ctx->page_front, "True");
    ctx->page_front += 4;
  }

  return uw_unit_v;
}

#define TIME_FMT "%x %X"
#define TIME_FMT_PG "%Y-%m-%d %T"

uw_Basis_string uw_Basis_htmlifyTime(uw_context ctx, uw_Basis_time t) {
  size_t len;
  char *r;
  struct tm stm;

  if (localtime_r(&t, &stm)) {
    uw_check_heap(ctx, TIMES_MAX);
    r = ctx->heap_front;
    len = strftime(r, TIMES_MAX, TIME_FMT, &stm);
    ctx->heap_front += len+1;
    return r;
  } else
    return "<i>Invalid time</i>";
}

uw_unit uw_Basis_htmlifyTime_w(uw_context ctx, uw_Basis_time t) {
  size_t len;
  char *r;
  struct tm stm;

  if (localtime_r(&t, &stm)) {
    uw_check(ctx, TIMES_MAX);
    r = ctx->page_front;
    len = strftime(r, TIMES_MAX, TIME_FMT, &stm);
    ctx->page_front += len;
  } else {
    uw_check(ctx, 20);
    strcpy(ctx->page_front, "<i>Invalid time</i>");
    ctx->page_front += 19;
  }

  return uw_unit_v;
}

uw_Basis_string uw_Basis_strcat(uw_context ctx, uw_Basis_string s1, uw_Basis_string s2) {
  int len = strlen(s1) + strlen(s2) + 1;
  char *s;

  uw_check_heap(ctx, len);

  s = ctx->heap_front;

  strcpy(s, s1);
  strcat(s, s2);
  ctx->heap_front += len;

  return s;
}

uw_Basis_string uw_Basis_strdup(uw_context ctx, uw_Basis_string s1) {
  int len = strlen(s1) + 1;
  char *s;

  uw_check_heap(ctx, len);

  s = ctx->heap_front;

  strcpy(s, s1);
  ctx->heap_front += len;

  return s;
}


char *uw_Basis_sqlifyInt(uw_context ctx, uw_Basis_int n) {
  int len;
  char *r;

  uw_check_heap(ctx, INTS_MAX + 6);
  r = ctx->heap_front;
  sprintf(r, "%lld::int8%n", n, &len);
  ctx->heap_front += len+1;
  return r;
}

char *uw_Basis_sqlifyIntN(uw_context ctx, uw_Basis_int *n) {
  if (n == NULL)
    return "NULL";
  else
    return uw_Basis_sqlifyInt(ctx, *n);
}

char *uw_Basis_sqlifyFloat(uw_context ctx, uw_Basis_float n) {
  int len;
  char *r;

  uw_check_heap(ctx, FLOATS_MAX + 8);
  r = ctx->heap_front;
  sprintf(r, "%g::float8%n", n, &len);
  ctx->heap_front += len+1;
  return r;
}

char *uw_Basis_sqlifyFloatN(uw_context ctx, uw_Basis_float *n) {
  if (n == NULL)
    return "NULL";
  else
    return uw_Basis_sqlifyFloat(ctx, *n);
}


uw_Basis_string uw_Basis_sqlifyString(uw_context ctx, uw_Basis_string s) {
  char *r, *s2;

  uw_check_heap(ctx, strlen(s) * 2 + 10);

  r = s2 = ctx->heap_front;
  *s2++ = 'E';
  *s2++ = '\'';

  for (; *s; s++) {
    char c = *s;

    switch (c) {
    case '\'':
      strcpy(s2, "\\'");
      s2 += 2;
      break;
    case '\\':
      strcpy(s2, "\\\\");
      s2 += 2;
      break;
    default:
      if (isprint(c))
        *s2++ = c;
      else {
        sprintf(s2, "\\%3o", c);
        s2 += 4;
      }
    }
  }

  strcpy(s2, "'::text");
  ctx->heap_front = s2 + 8;
  return r;
}

uw_Basis_string uw_Basis_sqlifyStringN(uw_context ctx, uw_Basis_string s) {
  if (s == NULL)
    return "NULL";
  else
    return uw_Basis_sqlifyString(ctx, s);
}

char *uw_Basis_sqlifyBool(uw_context ctx, uw_Basis_bool b) {
  if (b == uw_Basis_False)
    return "FALSE";
  else
    return "TRUE";
}

char *uw_Basis_sqlifyBoolN(uw_context ctx, uw_Basis_bool *b) {
  if (b == NULL)
    return "NULL";
  else
    return uw_Basis_sqlifyBool(ctx, *b);
}

char *uw_Basis_sqlifyTime(uw_context ctx, uw_Basis_time t) {
  size_t len;
  char *r;
  struct tm stm;

  if (localtime_r(&t, &stm)) {
    uw_check_heap(ctx, TIMES_MAX);
    r = ctx->heap_front;
    len = strftime(r, TIMES_MAX, TIME_FMT, &stm);
    ctx->heap_front += len+1;
    return r;
  } else
    return "<Invalid time>";
}

char *uw_Basis_sqlifyTimeN(uw_context ctx, uw_Basis_time *t) {
  if (t == NULL)
    return "NULL";
  else
    return uw_Basis_sqlifyTime(ctx, *t);
}

char *uw_Basis_ensqlBool(uw_Basis_bool b) {
  static uw_Basis_int true = 1;
  static uw_Basis_int false = 0;

  if (b == uw_Basis_False)
    return (char *)&false;
  else
    return (char *)&true;
}

uw_Basis_string uw_Basis_intToString(uw_context ctx, uw_Basis_int n) {
  int len;
  char *r;

  uw_check_heap(ctx, INTS_MAX);
  r = ctx->heap_front;
  sprintf(r, "%lld%n", n, &len);
  ctx->heap_front += len+1;
  return r;
}

uw_Basis_string uw_Basis_floatToString(uw_context ctx, uw_Basis_float n) {
  int len;
  char *r;

  uw_check_heap(ctx, FLOATS_MAX);
  r = ctx->heap_front;
  sprintf(r, "%g%n", n, &len);
  ctx->heap_front += len+1;
  return r;
}

uw_Basis_string uw_Basis_boolToString(uw_context ctx, uw_Basis_bool b) {
  if (b == uw_Basis_False)
    return "False";
  else
    return "True";
}

uw_Basis_string uw_Basis_timeToString(uw_context ctx, uw_Basis_time t) {
  size_t len;
  char *r;
  struct tm stm;

  if (localtime_r(&t, &stm)) {
    uw_check_heap(ctx, TIMES_MAX);
    r = ctx->heap_front;
    len = strftime(r, TIMES_MAX, TIME_FMT, &stm);
    ctx->heap_front += len+1;
    return r;
  } else
    return "<Invalid time>";
}

uw_Basis_int *uw_Basis_stringToInt(uw_context ctx, uw_Basis_string s) {
  char *endptr;
  uw_Basis_int n = strtoll(s, &endptr, 10);

  if (*s != '\0' && *endptr == '\0') {
    uw_Basis_int *r = uw_malloc(ctx, sizeof(uw_Basis_int));
    *r = n;
    return r;
  } else
    return NULL;
}

uw_Basis_float *uw_Basis_stringToFloat(uw_context ctx, uw_Basis_string s) {
  char *endptr;
  uw_Basis_float n = strtod(s, &endptr);

  if (*s != '\0' && *endptr == '\0') {
    uw_Basis_float *r = uw_malloc(ctx, sizeof(uw_Basis_float));
    *r = n;
    return r;
  } else
    return NULL;
}

uw_Basis_bool *uw_Basis_stringToBool(uw_context ctx, uw_Basis_string s) {
  static uw_Basis_bool true = uw_Basis_True;
  static uw_Basis_bool false = uw_Basis_False;

  if (!strcasecmp (s, "True"))
    return &true;
  else if (!strcasecmp (s, "False"))
    return &false;
  else
    return NULL;
}

uw_Basis_time *uw_Basis_stringToTime(uw_context ctx, uw_Basis_string s) {
  char *dot = strchr(s, '.'), *end = strchr(s, 0);
  struct tm stm;

  if (dot) {
    *dot = 0;
    if (strptime(s, TIME_FMT_PG, &stm) == end) {
      *dot = '.';
      uw_Basis_time *r = uw_malloc(ctx, sizeof(uw_Basis_time));
      *r = mktime(&stm);
      return r;
    }
    else {
      *dot = '.';
      return NULL;
    }
  }
  else {
    if (strptime(s, TIME_FMT_PG, &stm) == end) {
      uw_Basis_time *r = uw_malloc(ctx, sizeof(uw_Basis_time));
      *r = mktime(&stm);
      return r;
    }
    else if (strptime(s, TIME_FMT, &stm) == end) {
      uw_Basis_time *r = uw_malloc(ctx, sizeof(uw_Basis_time));
      *r = mktime(&stm);
      return r;
    }
    else
      return NULL;
  }
}

uw_Basis_int uw_Basis_stringToInt_error(uw_context ctx, uw_Basis_string s) {
  char *endptr;
  uw_Basis_int n = strtoll(s, &endptr, 10);

  if (*s != '\0' && *endptr == '\0')
    return n;
  else
    uw_error(ctx, FATAL, "Can't parse int: %s", s);
}

uw_Basis_float uw_Basis_stringToFloat_error(uw_context ctx, uw_Basis_string s) {
  char *endptr;
  uw_Basis_float n = strtod(s, &endptr);

  if (*s != '\0' && *endptr == '\0')
    return n;
  else
    uw_error(ctx, FATAL, "Can't parse float: %s", s);
}

uw_Basis_bool uw_Basis_stringToBool_error(uw_context ctx, uw_Basis_string s) {
  if (!strcasecmp(s, "T") || !strcasecmp (s, "True"))
    return uw_Basis_True;
  else if (!strcasecmp(s, "F") || !strcasecmp (s, "False"))
    return uw_Basis_False;
  else
    uw_error(ctx, FATAL, "Can't parse bool: %s", s);
}

uw_Basis_time uw_Basis_stringToTime_error(uw_context ctx, uw_Basis_string s) {
  char *dot = strchr(s, '.'), *end = strchr(s, 0);
  struct tm stm = {};

  if (dot) {
    *dot = 0;
    if (strptime(s, TIME_FMT_PG, &stm)) {
      *dot = '.';
      return mktime(&stm);
    }
    else {
      *dot = '.';
      uw_error(ctx, FATAL, "Can't parse time: %s", s);
    }
  }
  else {
    if (strptime(s, TIME_FMT_PG, &stm) == end)
      return mktime(&stm);
    else if (strptime(s, TIME_FMT, &stm) == end)
      return mktime(&stm);
    else
      uw_error(ctx, FATAL, "Can't parse time: %s", s);
  }
}

uw_Basis_string uw_Basis_requestHeader(uw_context ctx, uw_Basis_string h) {
  int len = strlen(h);
  char *s = ctx->headers, *p;

  while (p = strchr(s, ':')) {
    if (p - s == len && !strncasecmp(s, h, len)) {
      return p + 2;
    } else {
      if ((s = strchr(p, 0)) && s < ctx->headers_end)
        s += 2;
      else
        return NULL;
    }
  }
}

uw_Basis_string uw_Basis_get_cookie(uw_context ctx, uw_Basis_string c) {
  int len = strlen(c);
  char *s = ctx->headers, *p;

  while (p = strchr(s, ':')) {
    if (!strncasecmp(s, "Cookie: ", 8) && !strncmp(p + 2, c, len)
        && p + 2 + len < ctx->headers_end && p[2 + len] == '=') {
      return p + 3 + len;
    } else {
      if ((s = strchr(p, 0)) && s < ctx->headers_end)
        s += 2;
      else
        return NULL;
    }
  }
}

uw_unit uw_Basis_set_cookie(uw_context ctx, uw_Basis_string prefix, uw_Basis_string c, uw_Basis_string v) {
  uw_write_header(ctx, "Set-Cookie: ");
  uw_write_header(ctx, c);
  uw_write_header(ctx, "=");
  uw_write_header(ctx, v);
  uw_write_header(ctx, "; path=");
  uw_write_header(ctx, prefix);
  uw_write_header(ctx, "\r\n");

  return uw_unit_v;
}