/* vi: set sw=4 ts=4:
 *
 * sort.c - put input lines into order
 *
 * Copyright 2004, 2008 Rob Landley <rob@landley.net>
 *
 * See http://www.opengroup.org/onlinepubs/007904975/utilities/sort.html

USE_SORT(NEWTOY(sort, USE_SORT_BIG("S:T:m" "o:k*t:bgMcszdfi") "run", TOYFLAG_USR|TOYFLAG_BIN))

config SORT
    bool "sort"
    default y
    help
      usage: sort [-run] [FILE...]

      Sort all lines of text from input files (or stdin) to stdout.

      -r    reverse
      -u    unique lines only
      -n    numeric order (instead of alphabetical)

config SORT_BIG
    bool "  all SuSv3 options (Support -ktcsbdfiozgM)"
    default y
    depends on SORT
    help
      usage: sort [-bcdfgiMsz] [-k#[,#[x]] [-t X]] [-o FILE]

      -b    ignore leading blanks (or trailing blanks in second part of key)
      -c    check whether input is sorted
      -d    dictionary order (use alphanumeric and whitespace chars only)
      -f    force uppercase (case insensitive sort)
      -g    general numeric sort (double precision with nan and inf)
      -i    ignore nonprinting characters
      -M    month sort (jan, feb, etc).
      -s    skip fallback sort (only sort with keys)
      -z    zero (null) terminated input
      -k    sort by "key" (see below)
      -t    use a key separator other than whitespace
      -o    output to FILE instead of stdout

      This version of sort requires floating point.

      Sorting by key looks at a subset of the words on each line.  -k2
      uses the second word to the end of the line, -k2,2 looks at only
      the second word, -k2,4 looks from the start of the second to the end
      of the fourth word.  Specifying multiple keys uses the later keys as
      tie breakers, in order.  A type specifier appended to a sort key
          (such as -2,2n) applies only to sorting that key.
*/

#include "toys.h"
#include <math.h>

DEFINE_GLOBALS(
    char *key_separator;
    struct arg_list *raw_keys;
    char *outfile;
    char *ignore1, ignore2;   // GNU compatability NOPs for -S and -T.

    void *key_list;
    int linecount;
    char **lines;
)

#define TT this.sort

// The sort types are n, g, and M.
// u, c, s, and z apply to top level only, not to keys.
// b at top level implies bb.
// The remaining options can be applied to search keys.

#define FLAG_n      1  // Sort type: numeric
#define FLAG_u      2  // Unique
#define FLAG_r      4  // Reverse output order

#define FLAG_i      8  // Ignore !isprint()
#define FLAG_f     16  // Force uppercase
#define FLAG_d     32  // Ignore !(isalnum()|isspace())
#define FLAG_z     64  // Input is null terminated, not \n
#define FLAG_s    128  // Stable sort, no ascii fallback at end
#define FLAG_c    256  // Check only.  No output, exit(!ordered)
#define FLAG_M    512  // Sort type: date
#define FLAG_g   1024  // Sort type: strtod()
#define FLAG_b   2048  // Ignore leading blanks

// Left off dealing with FLAG_b/FLAG_bb logic...

#define FLAG_bb 32768  // Ignore trailing blanks

struct sort_key
{
    struct sort_key *next_key;  // linked list
    unsigned range[4];          // start word, start char, end word, end char
    int flags;
};

// Copy of the part of this string corresponding to a key/flags.

static char *get_key_data(char *str, struct sort_key *key, int flags)
{
    int start=0, end, len, i, j;

    // Special case whole string, so we don't have to make a copy

    if(key->range[0]==1 && !key->range[1] && !key->range[2] && !key->range[3]
        && !(flags&(FLAG_b&FLAG_d&FLAG_f&FLAG_i&FLAG_bb))) return str;

    // Find start of key on first pass, end on second pass

    len = strlen(str);
    for (j=0; j<2; j++) {
        if (!key->range[2*j]) end=len;

        // Loop through fields
        else {
            end=0;
            for (i=1; i < key->range[2*j]+j; i++) {

                // Skip leading blanks
                if (str[end] && !TT.key_separator)
                    while (isspace(str[end])) end++;

                // Skip body of key
                for (; str[end]; end++) {
                    if (TT.key_separator) {
                        if (str[end]==*TT.key_separator) break;
                    } else if (isspace(str[end])) break;
                }
            }
        }
        if (!j) start=end;
    }

    // Key with explicit separator starts after the separator
    if (TT.key_separator && str[start]==*TT.key_separator) start++;

    // Strip leading and trailing whitespace if necessary
    if (flags&FLAG_b) while (isspace(str[start])) start++;
    if (flags&FLAG_bb) while (end>start && isspace(str[end-1])) end--;

    // Handle offsets on start and end
    if (key->range[3]) {
        end += key->range[3]-1;
        if (end>len) end=len;
    }
    if (key->range[1]) {
        start += key->range[1]-1;
        if (start>len) start=len;
    }

    // Make the copy
    if (end<start) end=start;
    str = xstrndup(str+start, end-start);

    // Handle -d
    if (flags&FLAG_d) {
        for (start = end = 0; str[end]; end++)
            if (isspace(str[end]) || isalnum(str[end])) str[start++] = str[end];
        str[start] = 0;
    }

    // Handle -i
    if (flags&FLAG_i) {
        for (start = end = 0; str[end]; end++)
            if (isprint(str[end])) str[start++] = str[end];
        str[start] = 0;
    }

    // Handle -f
    if (flags*FLAG_f) for(i=0; str[i]; i++) str[i] = toupper(str[i]);

    return str;
}

// append a sort_key to key_list.

static struct sort_key *add_key(void)
{
    void **stupid_compiler = &TT.key_list;
    struct sort_key **pkey = (struct sort_key **)stupid_compiler;

    while (*pkey) pkey = &((*pkey)->next_key);
    return *pkey = xzalloc(sizeof(struct sort_key));
}

// Perform actual comparison
static int compare_values(int flags, char *x, char *y)
{
    int ff = flags & (FLAG_n|FLAG_g|FLAG_M);

    // Ascii sort
    if (!ff) return strcmp(x, y);

    if (CFG_SORT_BIG && ff == FLAG_g) {
        char *xx,*yy;
        double dx = strtod(x,&xx), dy = strtod(y,&yy);
        int xinf, yinf;

        // not numbers < NaN < -infinity < numbers < +infinity)

        if (x==xx) return y==yy ? 0 : -1;
        if (y==yy) return 1;

        // Check for isnan
        if (dx!=dx) return (dy!=dy) ? 0 : -1;
        if (dy!=dy) return 1;

        // Check for infinity.  (Could underflow, but avoids needing libm.)
        xinf = (1.0/dx == 0.0);
        yinf = (1.0/dy == 0.0);
        if (xinf) {
            if(dx<0) return (yinf && dy<0) ? 0 : -1;
            return (yinf && dy>0) ? 0 : 1;
        }
        if (yinf) return dy<0 ? 1 : -1;

        return dx>dy ? 1 : (dx<dy ? -1 : 0);
    } else if (CFG_SORT_BIG && ff == FLAG_M) {
        struct tm thyme;
        int dx;
        char *xx,*yy;

        xx = strptime(x,"%b",&thyme);
        dx = thyme.tm_mon;
        yy = strptime(y,"%b",&thyme);
        if (!xx) return !yy ? 0 : -1;
        else if (!yy) return 1;
        else return dx==thyme.tm_mon ? 0 : dx-thyme.tm_mon;

    // This has to be ff == FLAG_n
    } else {
        // Full floating point version of -n
        if (CFG_SORT_BIG) {
            double dx = atof(x), dy = atof(y);

            return dx>dy ? 1 : (dx<dy ? -1 : 0);
        // Integer version of -n for tiny systems
        } else return atoi(x)-atoi(y);
    }
}


// Callback from qsort(): Iterate through key_list and perform comparisons.
static int compare_keys(const void *xarg, const void *yarg)
{
    int flags = toys.optflags, retval = 0;
    char *x, *y, **xx = (char **)xarg, **yy = (char **)yarg;
    struct sort_key *key;

    if (CFG_SORT_BIG) {
        for (key=(struct sort_key *)TT.key_list; !retval && key;
             key = key->next_key)
        {
            flags = key->flags ? key->flags : toys.optflags;

            // Chop out and modify key chunks, handling -dfib

            x = get_key_data(*xx, key, flags);
            y = get_key_data(*yy, key, flags);

            retval = compare_values(flags, x, y);

            // Free the copies get_key_data() made.

            if (x != *xx) free(x);
            if (y != *yy) free(y);

            if (retval) break;
        }
    } else retval = compare_values(flags, *xx, *yy);

    // Perform fallback sort if necessary
    if (!retval && !(CFG_SORT_BIG && (toys.optflags&FLAG_s))) {
        retval = strcmp(*xx, *yy);
        flags = toys.optflags;
    }

    return retval * ((flags&FLAG_r) ? -1 : 1);
}

// Callback from loopfiles to handle input files.
static void sort_read(int fd, char *name)
{
    // Read each line from file, appending to a big array.

    for (;;) {
        char * line = (CFG_SORT_BIG && (toys.optflags&FLAG_z))
                       ? get_rawline(fd, NULL, 0) : get_line(fd);

        if (!line) break;

        // handle -c here so we don't allocate more memory than necessary.
        if (CFG_SORT_BIG && (toys.optflags&FLAG_c)) {
            int j = (toys.optflags&FLAG_u) ? -1 : 0;

            if (TT.linecount && compare_keys((char *)TT.lines,line)>j)
                error_exit("%s: Check line %d\n", name, TT.linecount);

            if (TT.lines) free(TT.lines);
            else TT.linecount = 0;
            TT.lines = (char **)line;
        } else {
            if (!(TT.linecount&63))
                TT.lines = xrealloc(TT.lines, sizeof(char *)*(TT.linecount+64));
            TT.lines[TT.linecount] = line;
        }
        TT.linecount++;
    }
}

void sort_main(void)
{
    int idx, fd = 1;

    // Open output file if necessary.
    if (CFG_SORT_BIG && TT.outfile)
        fd = xcreate(TT.outfile, O_CREAT|O_TRUNC|O_WRONLY, 0666);

    // Parse -k sort keys.
    if (CFG_SORT_BIG && TT.raw_keys) {
        struct arg_list *arg;
 
        for (arg = TT.raw_keys; arg; arg = arg->next) {
            struct sort_key *key = add_key();
            char *temp;
            int flag;

            idx = 0;
            temp = arg->arg;
            while (*temp) {
                // Start of range
                key->range[2*idx] = (unsigned)strtol(temp, &temp, 10);
                if (*temp=='.')
                    key->range[(2*idx)+1] = (unsigned)strtol(temp+1, &temp, 10);

                // Handle flags appended to a key type.
                for (;*temp;temp++) {
                    char *temp2, *optlist;

                    // Note that a second comma becomes an "Unknown key" error.

                    if (*temp==',' && !idx++) {
                        temp++;
                        break;
                    }

                    // Which flag is this?

                    optlist = toys.which->options;
                    temp2 = index(optlist, *temp);
                    flag = (1<<(optlist-temp2+strlen(optlist)-1));

                    // Was it a flag that can apply to a key?

                    if (!temp2 || flag>FLAG_b
                        || (flag&(FLAG_u|FLAG_c|FLAG_s|FLAG_z)))
                    {
                        error_exit("Unknown key option.");
                    }
                    // b after , means strip _trailing_ space, not leading.
                    if (idx && flag==FLAG_b) flag = FLAG_bb;
                    key->flags |= flag;
                }
            }
        }
    }

    // global b flag strips both leading and trailing spaces
    if (toys.optflags&FLAG_b) toys.optflags |= FLAG_bb;

    // If no keys, perform alphabetic sort over the whole line.
    if (CFG_SORT_BIG && !TT.key_list) add_key()->range[0] = 1;

    // Open input files and read data, populating TT.lines[TT.linecount]
    loopfiles(toys.optargs, sort_read);

    // The compare (-c) logic was handled in sort_read(),
    // so if we got here, we're done.
    if (CFG_SORT_BIG && (toys.optflags&FLAG_c)) return;

    // Perform the actual sort
    qsort(TT.lines, TT.linecount, sizeof(char *), compare_keys);

    // handle unique (-u)
    if (toys.optflags&FLAG_u) {
        int jdx;

        for (jdx=0, idx=1; idx<TT.linecount; idx++) {
            if (!compare_keys(&TT.lines[jdx], &TT.lines[idx]))
                free(TT.lines[idx]);
            else TT.lines[++jdx] = TT.lines[idx];
        }
        if (TT.linecount) TT.linecount = jdx+1;
    }

    // Output result
    for (idx = 0; idx<TT.linecount; idx++) {
        char *s = TT.lines[idx];
        xwrite(fd, s, strlen(s));
        if (CFG_TOYBOX_FREE) free(s);
        xwrite(fd, "\n", 1);
    }

    if (CFG_TOYBOX_FREE) {
      if (fd != 1) close(fd);
      free(TT.lines);
    }
}