/* build.c - Simple, POSIX, non-Cytoplasm utility to build out 
 * the entirety of Parsee from scratch, without any Makefiles.
 *
 * The main reason why this tool exists is merely because the 
 * current Make-based building is not POSIX compliant, and I 
 * am simply not porting it to be. The Makefile shall stay 
 * supported however, but if possible, use build.c.
 * To run it, just build it with:
 *  cc build.c -o /tmp/build && /tmp/build
 *
 * TODO: Parallel jobs, CFLAGS and LDFLAGS.
 *
 * Note that this bit is formatted differently.
 * --------------------------------
 * LICENSE: CC0
 * Written-By: LDA [lda@freetards.xyz] [@fourier:ari.lt] */

#include <sys/wait.h>
#include <sys/stat.h>
#include <stdbool.h>
#include <dirent.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>

#define DEFAULT_BUILD_PATH              "build.conf"
#define DEFAULT_COMPILER                "cc"
#define Compiler(info)  (info.basic.cc ? info.basic.cc : DEFAULT_COMPILER)

static char *
string_rep_ext(char *in, char *ext1, char *ext2)
{
    char *end;
    size_t inLen;
    if (!in || !ext1 || !ext2)
    {
        return NULL;
    }

    inLen = strlen(in);
    end = inLen + in;

    while (end >= in)
    {
        if (!strcmp(end, ext1))
        {
            size_t cpyLen = end - in;
            size_t extLen = strlen(ext2);
            char *ret = malloc(cpyLen + extLen + 1);

            memcpy(ret, in, cpyLen);
            memcpy(ret + cpyLen, ext2, extLen);
            ret[cpyLen + extLen] = '\0';
            return ret;
        }
        end--;
    }
    return NULL;
}
static char *
string_dup(char *in)
{
    char *out;
    size_t len;
    if (!in)
    {
        return NULL;
    }
    len = strlen(in);
    out = malloc(len + 1);
    memcpy(out, in, len);
    out[len] = '\0';

    return out;
}
static char *
string_cat(char *in1, char *in2)
{
    char *out;
    size_t len1, len2;
    if (!in1)
    {
        return string_dup(in2);
    }
    if (!in2)
    {
        return string_dup(in1);
    }

    len1 = strlen(in1);
    len2 = strlen(in2);
    out = malloc(len1 + len2 + 1);
    memcpy(out, in1, len1);
    memcpy(out + len1, in2, len2);
    out[len1 + len2] = '\0';

    return out;
}
static char *
trim_nl(char *in)
{
    char *tc;
    if (!in)
    {
        return NULL;
    }

    while ((tc = strrchr(in, '\n')))
    {
        *tc = '\0';
    }

    return in;
}

typedef struct str_array {
    char **values;
    size_t quantity;
} str_array_t;
static str_array_t *
str_array_create(void)
{
    str_array_t *ret = malloc(sizeof(*ret));

    ret->values = NULL;
    ret->quantity = 0;
    return ret;
}
static void
str_array_free(str_array_t *arr)
{
    size_t i;
    if (!arr)
    {
        return;
    }

    for (i = 0; i < arr->quantity; i++)
    {
        if (arr->values[i]) free(arr->values[i]);
    }
    if (arr->values) free(arr->values);
    free(arr);
}
static void
str_array_set(str_array_t *arr, size_t i, char *str)
{
    if (!arr)
    {
        return;
    }

    if (i >= arr->quantity)
    {
        size_t size = (i+1) * sizeof(*arr->values);
        size_t j;
        arr->values = realloc(arr->values, size);
        for (j = arr->quantity; j <= i; j++)
        {
            arr->values[j] = NULL;
        }
        arr->quantity = i + 1 ;
    }
    if (arr->values[i]) free(arr->values[i]);
    arr->values[i] = string_dup(str);
}
static void
str_array_add(str_array_t *arr, char *str)
{
    if (!arr)
    {
        return;
    }
    str_array_set(arr, arr->quantity, str);
}
static char *
str_array_get(str_array_t *arr, size_t i)
{
    if (!arr)
    {
        return NULL;
    }
    return i < arr->quantity ? arr->values[i] : NULL;
}
static size_t
str_array_len(str_array_t *arr)
{
    return arr ? arr->quantity : 0;
}

typedef struct buildinfo {
    struct basic {
        char *codename;
        char *version;

        char *name;

        char *binary;

        char *src;
        char *inc;
        char *obj;

        char *cc;
    } basic;

    char *repo;
} buildinfo_t;
static void
destroy_buildinfo(buildinfo_t *info)
{
    if (!info)
    {
        return;
    }
    
    if (info->basic.codename)
    {
        free(info->basic.codename);
        info->basic.codename = NULL;
    }
    if (info->basic.version)
    {
        free(info->basic.version);
        info->basic.version = NULL;
    }
    if (info->basic.name)
    {
        free(info->basic.name);
        info->basic.name = NULL;
    }
    if (info->basic.binary)
    {
        free(info->basic.binary);
        info->basic.binary = NULL;
    }
    if (info->basic.src)
    {
        free(info->basic.src);
        info->basic.src = NULL;
    }
    if (info->basic.inc)
    {
        free(info->basic.inc);
        info->basic.inc = NULL;
    }
    if (info->basic.obj)
    {
        free(info->basic.obj);
        info->basic.obj = NULL;
    }

    if (info->repo)
    {
        free(info->repo);
        info->repo = NULL;
    }
}

static char *
cmd_stdout(char *cmd)
{
    FILE *f;
    char *line = NULL;
    size_t size;
    if (!cmd)
    {
        return NULL;
    }
    if (!(f = popen(cmd, "r")))
    {
        return NULL;
    }

    getline(&line, &size, f);
    pclose(f);
    return line;
}
static int
exec_code(char *program, char *argv[])
{
    pid_t forkRet;
    if (!program || !argv)
    {
        return -1;
    }

    forkRet = fork();
    if (forkRet == 0)
    {
        /* Child */
        execvp(program, argv);
        exit(0);
    }
    else
    {
        /* Parent */
        int status;
        if (waitpid(forkRet, &status, 0) == -1)
        {
            return -1;
        }
        return status;
    }
}


static char *
strchrn(char *s, char c)
{
    s = strchr(s, c);
    return s ? s+1 : NULL;
}
static char *
strchrl(char *s, char c)
{
    char *s1 = NULL;
    while ((s = strchr(s, c)))
    {
        s1 = s;
        s++;
    }
    return s1;
}
static void
mkdir_rec(char *dir)
{
    char tmp[PATH_MAX];
    char *start;
    if (!dir || strlen(dir) >= PATH_MAX - 1)
    {
        return;
    }

    memset(tmp, '\0', sizeof(tmp));
    for (start = dir; start && *start; start = strchrn(start, '/'))
    {
        char subtmp[PATH_MAX];
        char *next = strchr(start, '/');
        if (!next)
        {
            next = start + strlen(start);
        }
        memcpy(subtmp, start, next - start);
        subtmp[next - start] = '\0';

        {
            memcpy(tmp, dir, start - dir);
            tmp[strlen(tmp) - 1] = '\0';
            mkdir(tmp, 0770);
        }
    }
}
static bool
build_file(char *cSource, buildinfo_t info, bool isTool)
{
    char *args[16] = { 0 };
    char *oFileName, *objPath, *oFile;
    int ret, i = 0;
    int srclen;

    char *code, *name, *vers, *repo;
    if (!cSource)
    {
        return false;
    }

    if (!isTool)
    {
        srclen      = strncmp(cSource, "src", 3) ?
            strlen(info.basic.obj) + 1 :
            strlen(info.basic.src) + 1 ;
        objPath     = string_cat(info.basic.obj, "/");
        oFile       = string_rep_ext(cSource + srclen, ".c", ".o");
        oFileName   = string_cat(objPath, oFile);
    }
    else
    {
        srclen      = 6;
        objPath     = string_dup("tools/out/");
        oFile       = string_rep_ext(cSource + srclen, ".c", "");
        oFileName   = string_cat(objPath, oFile);
    }
    mkdir_rec(oFileName);

    args[i++]   = Compiler(info);
    if (isTool)
    {
        args[i++]   = "-lCytoplasm";
        args[i++]   = "-I.";
    }
    else
    {
        args[i++]   = "-c";
    }
    args[i++]   = cSource;
    args[i++]   = "-o";
    args[i++]   = oFileName;

    args[i++]   = "-I";
    args[i++]   = info.basic.inc;
    args[i++]   = "-I";
    args[i++]   = info.basic.src;
    
    {
        char *pre = string_cat("\"", info.basic.version);
        char *pos = string_cat(pre, "\"");
        vers = string_cat("-DVERSION=", pos);
        args[i++]   = vers;

        free(pos);
        free(pre);
    }
    {
        char *pre = string_cat("\"", info.basic.name);
        char *pos = string_cat(pre, "\"");
        name = string_cat("-DNAME=", pos);
        args[i++]   = name;

        free(pos);
        free(pre);
    }
    {
        char *pre = string_cat("\"", info.basic.codename);
        char *pos = string_cat(pre, "\"");
        code = string_cat("-DCODE=", pos);
        args[i++]   = code;

        free(pos);
        free(pre);
    }
    {
        char *pre = string_cat("\"", info.repo);
        char *pos = string_cat(pre, "\"");
        repo = string_cat("-DREPOSITORY=", pos);
        args[i++]   = repo;

        free(pos);
        free(pre);
    }

    args[i++]   = NULL;
    
    ret = exec_code(Compiler(info), args);
    free(objPath);
    free(oFileName);
    free(oFile);
    free(vers);
    free(name);
    free(code);
    free(repo);
    return ret == EXIT_SUCCESS;
}
static bool
finalise_file(str_array_t *arr, buildinfo_t info)
{
    str_array_t *flags;
    size_t i;
    bool ret = true;
    if (!arr)
    {
        return false;
    }

    flags = str_array_create();
    str_array_add(flags, Compiler(info));

    str_array_add(flags, "-lCytoplasm");

    for (i = 0; i < str_array_len(arr); i++)
    {
        char *file = str_array_get(arr, i);
        if (file)
        {
            size_t srclen   = strncmp(file, "src", 3) ?
                strlen(info.basic.obj) + 1 :
                strlen(info.basic.src) + 1 ;
            char *objPath   = string_cat(info.basic.obj, "/");
            char *oFile     = string_rep_ext(file + srclen, ".c", ".o");
            char *oFileName = string_cat(objPath, oFile);

            str_array_add(flags, oFileName);

            free(oFileName);
            free(oFile);
            free(objPath);
        }
    }

    str_array_add(flags, "-o");
    str_array_add(flags, info.basic.binary);
    str_array_add(flags, NULL);
    ret = exec_code(Compiler(info), flags->values);
    
    str_array_free(flags);
    return ret;
}

static str_array_t *
collect_sources(char *dir, bool head, char *ext)
{
    DIR *handle;
    str_array_t *ret;
    struct dirent *ent;
    if (!dir)
    {
        return NULL;
    }

    ret = str_array_create();
    handle = opendir(dir);
    if (!handle)
    {
        printf("error: cannot open directory '%s'\n", dir);
        return ret;
    }
    while ((ent = readdir(handle)))
    {
        char *name = ent->d_name;
        if (*name == '.') continue;

        if (strlen(name) > strlen(ext) && 
            !strcmp(name + strlen(name) - strlen(ext), ext))
        {
            char *d1 = string_cat(dir, "/");
            char *na = string_cat(d1, name);
            str_array_add(ret, na);
            free(d1);
            free(na);
            continue;
        }
        if (!strchr(name, '.') && 
            strcmp(name, "out") &&
            strcmp(name, "Makefile"))
        {
            str_array_t *sub;
            char *d1 = string_cat(dir, "/");
            char *d2 = string_cat(d1, name);
            size_t i;

            sub = collect_sources(d2, false, ext);
            for (i = 0; i < str_array_len(sub); i++)
            {
                char *file = str_array_get(sub, i);
                str_array_add(ret, file);
            }
            str_array_free(sub);
            free(d2);
            free(d1);
        }
    }
    closedir(handle);
    return ret;
}

static char *
process_png(char *png, buildinfo_t info)
{
    size_t i = 0;
    char *symbol;
    char *cFile, *oFile;
    char *pcFile, *poFile;
    char *pcFile1, *poFile1;
    char *filename, *symbol1;
    char *arguments[8] = { 0 };
    if (!png)
    {
        return NULL;
    }

    if (!(filename = strchrl(png, '/')))
    {
        return NULL;
    }
    filename++;

    pcFile1= string_cat(info.basic.obj, "/");
    pcFile = string_cat(pcFile1, filename);
    cFile = string_rep_ext(pcFile, ".png", ".c");
    free(pcFile);
    free(pcFile1);

    poFile1= string_cat(info.basic.obj, "/");
    poFile = string_cat(poFile1, filename);
    oFile = string_rep_ext(poFile, ".png", ".o");
    free(poFile);
    free(poFile1);

    symbol1 = string_rep_ext(filename, ".png", "");
    symbol = string_cat("media_", symbol1);
    free(symbol1);

    mkdir_rec(oFile);
    mkdir_rec(cFile);

    /* Build the image into Base64 */
    arguments[i++] = "tools/out/b64";
    arguments[i++] = png;
    arguments[i++] = symbol;
    arguments[i++] = cFile;
    arguments[i++] = NULL;

    if (exec_code(arguments[0], arguments))
    {
        free(symbol);
        free(cFile);
        free(oFile);
        return NULL;
    }

    /* Compile it out */
    i = 0;
    arguments[i++] = Compiler(info);
    arguments[i++] = "-c";
    arguments[i++] = cFile;
    arguments[i++] = "-o";
    arguments[i++] = oFile;
    arguments[i++] = NULL;

    if (exec_code(arguments[0], arguments))
    {
        free(symbol);
        free(cFile);
        free(oFile);
        return NULL;
    }

    free(symbol);
    free(oFile);
    return cFile;
}
/* Builds the entirety of Parsee. */
static int
main_build(int argc, char *argv[])
{
    buildinfo_t info = { 0 };
    FILE *buildinfo = NULL;
    char *line = NULL;
    size_t size, i;
    ssize_t nread;
    str_array_t *sources, *images;

    /* Step 1: Get all basic information from build.conf */
    if (!(buildinfo = fopen(DEFAULT_BUILD_PATH, "r")))
    {
        printf("error: cannot open '%s'\n", DEFAULT_BUILD_PATH);
        goto fail;
    }
    while ((nread = getline(&line, &size, buildinfo)) != -1)
    {
        char *eq = strchr(line, '=');
        char *end = strchr(line, '\n');

        char *key, *val;
        if (!eq)
        {
            free(line);
            printf(
                "error: line in '%s' does not contain '='\n",
                DEFAULT_BUILD_PATH
            );
            goto fail;
        }

        /* Set delimiters */
        *eq = '\0';
        if (end) *end = '\0';

        key = line;
        val = eq + 1;

        /* Now, we have KV mappings. */
#define If(k, v, d) do \
        { \
            if (!strcmp(key, k) && !info.v) \
            { \
                info.v = string_dup(val); \
                printf("%s: %s\n", d, val); \
            } \
        } while (0)

        If("CODE", basic.codename, "Codename");
        If("NAME", basic.name, "Name");
        If("VERSION", basic.version, "Version");
        If("BINARY", basic.binary, "Binary name");

        If("INCLUDES", basic.inc, "Include path");
        If("SOURCE", basic.src, "Source path");
        If("OBJECT", basic.obj, "Object path");
        If("CC", basic.cc, "Compiler");
    }
    if (line)
    {
        free(line);
        line = NULL;
    }

    fclose(buildinfo);
    buildinfo = NULL;

    /* Step 2: Get all information from commands. */
    if (!(info.repo = cmd_stdout("git remote get-url origin")))
    {
        printf("error: cannot find origins url\n");
        goto fail;
    }
    info.repo = trim_nl(info.repo);


    /* Step 3: Build all utilities. */
    sources = collect_sources("tools", true, ".c");
    for (i = 0; i < str_array_len(sources); i++)
    {
        char *file = str_array_get(sources, i);
        printf("\tTOOL %s...\n", file);
        if (!build_file(file, info, true))
        {
            str_array_free(sources);
            goto fail;
        }
    }
    str_array_free(sources);

    /* Step 4: Build all media files. */
    sources = collect_sources(info.basic.src, true, ".c");
    images = collect_sources("etc/media", true, ".png");
    for (i = 0; i < str_array_len(images); i++)
    {
        char *file = str_array_get(images, i);
        char *out;

        out = process_png(file, info);
        if (!out)
        {
            str_array_free(images);
            str_array_free(sources);
            goto fail;
        }
        printf("\tPNG %s\n", file);
        str_array_add(sources, out);
        free(out);
    }
    str_array_free(images);

    /* Step 5: Build all of Parsee itself */
    for (i = 0; i < str_array_len(sources); i++)
    {
        char *file = str_array_get(sources, i);
        printf("\tCC %s...\n", file);
        if (!build_file(file, info, false))
        {
            str_array_free(sources);
            goto fail;
        }
    }
    printf("\tLINK\n");
    if (!finalise_file(sources, info))
    {
        str_array_free(sources);
        goto fail;
    }
    str_array_free(sources);
    /* Step 6: Build every Ayadoc */

    /* Step 7: Good! */

    destroy_buildinfo(&info);
    return EXIT_SUCCESS;
fail:
    if (buildinfo)
    {
        fclose(buildinfo);
        buildinfo = NULL;
    }
    destroy_buildinfo(&info);
    return EXIT_FAILURE;
}

int
main(int argc, char* argv[])
{
    /* TODO: Multiple flags(build/install/ayadoc/...) */
    return main_build(argc, argv);
}