/*
 * pkg - Repository scanner
 * https://rawnix.org
 *
 * Copyright (c) 2025 zorz@gmx.com
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include "repo.h"
#include <dirent.h>
#include <err.h>
#include <sys/stat.h>
#include <libgen.h>
#include <limits.h>
#include <unistd.h>

/*
 * Repo uses a larger bucket count than the default since
 * a typical ports tree has hundreds of entries and we want
 * fast lookups during dependency resolution.
 */
#define REPO_BUCKETS (HASH_BUCKETS * 2)

port_t *port_new(const char *name, const char *path, const char *collection)
{
    port_t *p = xmalloc(sizeof(port_t));

    p->name = xstrdup(name);
    p->path = xstrdup(path);
    p->collection = collection ? xstrdup(collection) : NULL;
    p->pkg = NULL;
    p->bad_name = false;
    return p;
}

void port_free(port_t *p)
{
    if (!p)
        return;
    free(p->name);
    free(p->path);
    free(p->collection);
    if (p->pkg)
        package_free(p->pkg);
    free(p);
}

bool port_recipe_locked(const port_t *p)
{
    char path[PATH_MAX];

    if (!p)
        return false;
    snprintf(path, sizeof(path), "%s/MAKEPKG.lock", p->path);
    return access(path, F_OK) == 0;
}

int port_load(port_t *p)
{
    char path[PATH_MAX];

    if (!p)
        return -1;
    if (p->pkg)
        return 0;

    p->pkg = package_new(p->name, p->path);

    /*
     * MAKEPKG.lock wins, exactly as in mkpkg.  `ports -u` overwrites
     * MAKEPKG with upstream's recipe but never the .lock, so this is
     * the operator's build.  Every decision pkg makes from a port —
     * deps for prepare/add/sysup, the version pkg_is_built() looks
     * for, what depdb records — has to come from the recipe mkpkg
     * will actually build.
     */
    snprintf(path, sizeof(path), "%s/%s", p->path,
             port_recipe_locked(p) ? "MAKEPKG.lock" : "MAKEPKG");
    if (makepkg_parse(path, p->pkg) != 0) {
        package_free(p->pkg);
        p->pkg = NULL;
        return -1;
    }


    /*
     * mkpkg names the package after name=, pkg looks for it under the
     * port's directory name.  They must be the same; a port where they
     * are not would build and then fail at install with "no package
     * file".  Refuse it up front, and say so once.
     */
    if (!p->pkg->name || strcmp(p->pkg->name, p->name) != 0) {
        if (!p->bad_name)
            warnx("port %s: MAKEPKG has name=%s; the port directory "
                  "and name= must be the same", p->path,
                  p->pkg->name ? p->pkg->name : "(none)");
        p->bad_name = true;
        package_free(p->pkg);
        p->pkg = NULL;
        return -1;
    }

    p->pkg->loaded = true;
    return 0;
}

repo_t *repo_new(void)
{
    repo_t *r = xmalloc(sizeof(repo_t));
    size_t i;

    r->bucket_count = REPO_BUCKETS;
    r->size = 0;
    r->buckets = xmalloc(r->bucket_count * sizeof(repo_hash_t *));

    for (i = 0; i < r->bucket_count; i++)
        r->buckets[i] = NULL;

    r->provides_buckets = NULL;
    r->provides_built = false;

    return r;
}

void repo_free(repo_t *r)
{
    size_t i;
    repo_hash_t *e, *next;

    if (!r)
        return;

    if (r->provides_buckets) {
        provides_hash_t *p, *pnext;
        for (i = 0; i < REPO_BUCKETS; i++) {
            p = r->provides_buckets[i];
            while (p) {
                pnext = p->next;
                free(p->key);
                strarray_free(&p->providers);
                free(p);
                p = pnext;
            }
        }
        free(r->provides_buckets);
    }

    for (i = 0; i < r->bucket_count; i++) {
        e = r->buckets[i];
        while (e) {
            next = e->next;
            free(e->key);
            port_free(e->port);
            free(e);
            e = next;
        }
    }

    free(r->buckets);
    free(r);
}

static int repo_add(repo_t *r, port_t *p)
{
    unsigned long hash;
    size_t idx;
    repo_hash_t *e, *existing;

    hash = hash_djb2(p->name);
    idx = hash % r->bucket_count;

    /* replace if exists (later collection wins) */
    for (existing = r->buckets[idx]; existing; existing = existing->next) {
        if (strcmp(existing->key, p->name) == 0) {
            port_free(existing->port);
            existing->port = p;
            return 0;
        }
    }

    e = xmalloc(sizeof(repo_hash_t));
    e->key = xstrdup(p->name);
    e->port = p;
    e->next = r->buckets[idx];
    r->buckets[idx] = e;
    r->size++;

    return 0;
}

int repo_scan(repo_t *r, const char *dir, const char *collection)
{
    DIR *d;
    struct dirent *ent;
    char path[PATH_MAX], makepkg[PATH_MAX + 16];
    struct stat st;
    port_t *p;
    int count = 0;

    d = opendir(dir);
    if (!d)
        return -1;

    while ((ent = readdir(d)) != NULL) {
        if (ent->d_name[0] == '.')
            continue;

        snprintf(path, sizeof(path), "%s/%s", dir, ent->d_name);

        if (stat(path, &st) != 0 || !S_ISDIR(st.st_mode))
            continue;

        /* a port holds a MAKEPKG, or only a MAKEPKG.lock -- the same
         * test as mkpkg's ports(8), which keeps a locked port whose
         * upstream recipe is gone */
        snprintf(makepkg, sizeof(makepkg), "%s/MAKEPKG", path);
        if (stat(makepkg, &st) != 0 || !S_ISREG(st.st_mode)) {
            snprintf(makepkg, sizeof(makepkg), "%s/MAKEPKG.lock", path);
            if (stat(makepkg, &st) != 0 || !S_ISREG(st.st_mode))
                continue;
        }

        p = port_new(ent->d_name, path, collection);
        if (repo_add(r, p) == 0)
            count++;
        else
            port_free(p);
    }

    closedir(d);
    return count;
}

int repo_scan_all(repo_t *r, char **dirs, size_t count)
{
    size_t i;
    int total = 0, n;
    char *copy, *col;

    for (i = 0; i < count; i++) {
        copy = xstrdup(dirs[i]);
        col = basename(copy);
        n = repo_scan(r, dirs[i], col);
        if (n > 0)
            total += n;
        free(copy);
    }

    return total;
}

port_t *repo_find(repo_t *r, const char *name)
{
    unsigned long hash;
    size_t idx;
    repo_hash_t *e;

    if (!r || !name)
        return NULL;

    hash = hash_djb2(name);
    idx = hash % r->bucket_count;

    for (e = r->buckets[idx]; e; e = e->next)
        if (strcmp(e->key, name) == 0)
            return e->port;

    return NULL;
}


strarray_t *repo_list(repo_t *r)
{
    strarray_t *arr;
    size_t i;
    repo_hash_t *e;

    arr = xmalloc(sizeof(strarray_t));
    strarray_init(arr);

    if (!r)
        return arr;

    for (i = 0; i < r->bucket_count; i++)
        for (e = r->buckets[i]; e; e = e->next)
            strarray_add(arr, e->key);

    return arr;
}

/*
 * Find variants of a package (e.g., vim-* for vim).
 *
 * A port only counts as a variant when its MAKEPKG declares a
 * variant=() description.  Matching on the name prefix alone is not
 * enough: unrelated packages legitimately share a prefix (hello vs
 * hello-data, foo vs foo-doc), and before this check `pkg add hello`
 * would stop at an interactive variant prompt — hanging scripted
 * runs — just because a sub-package existed.
 */
strarray_t *repo_find_variants(repo_t *r, const char *name)
{
    strarray_t *arr;
    size_t i, namelen;
    repo_hash_t *e;

    arr = xmalloc(sizeof(strarray_t));
    strarray_init(arr);

    if (!r || !name)
        return arr;

    namelen = strlen(name);

    for (i = 0; i < r->bucket_count; i++) {
        for (e = r->buckets[i]; e; e = e->next) {
            /* match "name-*" pattern */
            if (strncmp(e->key, name, namelen) != 0 ||
                e->key[namelen] != '-')
                continue;
            /* ...but only ports that declare variant=() */
            if (port_load(e->port) != 0)
                continue;
            if (e->port->pkg && e->port->pkg->variant &&
                e->port->pkg->variant->size > 0)
                strarray_add(arr, e->key);
        }
    }

    return arr;
}

/* Check if any package provides a virtual package */
bool repo_provides(repo_t *r, const char *name)
{
    strarray_t *prov = repo_providers(r, name);

    return prov != NULL && prov->size > 0;
}

/* ---- Provides index ---- */

static void provides_index_add(repo_t *r, const char *virt,
                               const char *port_name)
{
    unsigned long hash = hash_djb2(virt);
    size_t idx = hash % REPO_BUCKETS;
    provides_hash_t *e;

    for (e = r->provides_buckets[idx]; e; e = e->next) {
        if (strcmp(e->key, virt) == 0) {
            if (!strarray_contains(&e->providers, port_name))
                strarray_add(&e->providers, port_name);
            return;
        }
    }

    e = xmalloc(sizeof(provides_hash_t));
    e->key = xstrdup(virt);
    strarray_init(&e->providers);
    strarray_add(&e->providers, port_name);
    e->next = r->provides_buckets[idx];
    r->provides_buckets[idx] = e;
}

/*
 * Build the provides index in one pass over the repo.  This loads
 * every port (unavoidable — provides=() is only known after parsing),
 * but it happens at most ONCE per run.  Before this index, every
 * dep_satisfied() / find_provider() call walked and loaded the whole
 * tree, allocating a full name list each time.
 */
static void repo_build_provides(repo_t *r)
{
    size_t i, j;
    repo_hash_t *e;

    r->provides_buckets =
        xmalloc(REPO_BUCKETS * sizeof(provides_hash_t *));
    for (i = 0; i < REPO_BUCKETS; i++)
        r->provides_buckets[i] = NULL;

    for (i = 0; i < r->bucket_count; i++) {
        for (e = r->buckets[i]; e; e = e->next) {
            if (port_load(e->port) != 0)
                continue;
            if (!e->port->pkg || !e->port->pkg->provides)
                continue;
            for (j = 0; j < e->port->pkg->provides->size; j++)
                provides_index_add(r,
                                   e->port->pkg->provides->data[j],
                                   e->port->name);
        }
    }

    r->provides_built = true;
}

strarray_t *repo_providers(repo_t *r, const char *name)
{
    unsigned long hash;
    size_t idx;
    provides_hash_t *e;

    if (!r || !name)
        return NULL;

    if (!r->provides_built)
        repo_build_provides(r);

    hash = hash_djb2(name);
    idx = hash % REPO_BUCKETS;

    for (e = r->provides_buckets[idx]; e; e = e->next)
        if (strcmp(e->key, name) == 0)
            return &e->providers;

    return NULL;
}