#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <yaml.h>

#include "fpga.h"

/*
 * FPGA registry loaded at runtime from a YAML file (no longer a
 * compile-time array). Lookup order for the file:
 *   1. $BS_FPGA_REGISTRY (if set and non-empty)
 *   2. "fpga_registry.yaml" relative to the current directory
 * — the same CWD-relative convention as bsdl_files/ and bscan_proxies/,
 * so run bs_explorer from the repository root.
 *
 * Loaded lazily on first access and cached for the process lifetime.
 * The schema is one flat mapping per entry; see fpga_registry.yaml.
 */

#define DEFAULT_REGISTRY_FILE  "fpga_registry.yaml"

static fpga_target *g_registry = NULL;
static int          g_count    = 0;
static int          g_loaded   = 0;            /* load attempted (success or not) */
static char         g_source[1024] = "";

/* ---- small helpers ----------------------------------------------- */

static char *xstrdup(const char *s)
{
    char  *p;
    size_t n;
    if (!s) return NULL;
    n = strlen(s) + 1;
    p = (char *)malloc(n);
    if (p) memcpy(p, s, n);
    return p;
}

static fpga_family parse_family(const char *s)
{
    if (!s)                                        return FPGA_FAMILY_UNKNOWN;
    if (!strcmp(s, "xilinx_7"))                    return FPGA_FAMILY_XILINX_7;
    if (!strcmp(s, "xilinx_us"))                   return FPGA_FAMILY_XILINX_US;
    if (!strcmp(s, "xilinx_usp"))                  return FPGA_FAMILY_XILINX_USP;
    if (!strcmp(s, "microsemi_igloo2"))            return FPGA_FAMILY_MICROSEMI_IGLOO2;
    if (!strcmp(s, "microsemi_smartfusion2"))      return FPGA_FAMILY_MICROSEMI_SMARTFUSION2;
    if (!strcmp(s, "lattice_machxo2"))             return FPGA_FAMILY_LATTICE_MACHXO2;
    if (!strcmp(s, "lattice_machxo3"))             return FPGA_FAMILY_LATTICE_MACHXO3;
    fprintf(stderr, "fpga: unknown family '%s'\n", s);
    return FPGA_FAMILY_UNKNOWN;
}

static unsigned int parse_caveats(const char *s)
{
    unsigned int flags = 0;
    char         buf[256];
    char        *tok;

    if (!s) return 0;
    strncpy(buf, s, sizeof(buf) - 1);
    buf[sizeof(buf) - 1] = '\0';

    for (tok = strtok(buf, " ,|"); tok; tok = strtok(NULL, " ,|")) {
        if (!strcmp(tok, "cclk_via_startup"))
            flags |= FPGA_CAVEAT_CCLK_VIA_STARTUP;
        else
            fprintf(stderr, "fpga: unknown caveat '%s'\n", tok);
    }
    return flags;
}

/* Apply one "key: value" pair (both scalars) to the entry being built. */
static void set_field(fpga_target *t, const char *key, const char *val)
{
    if      (!strcmp(key, "name"))            { free((void *)t->name);            t->name = xstrdup(val); }
    else if (!strcmp(key, "idcode"))          t->idcode         = strtoul(val, NULL, 0);
    else if (!strcmp(key, "idcode_mask"))     t->idcode_mask    = strtoul(val, NULL, 0);
    else if (!strcmp(key, "family"))          t->family         = parse_family(val);
    else if (!strcmp(key, "bsdl"))            { free((void *)t->bsdl_filename);   t->bsdl_filename = xstrdup(val); }
    else if (!strcmp(key, "ir_length"))       t->ir_length      = (int)strtol(val, NULL, 0);
    else if (!strcmp(key, "ir_cfg_in"))       t->ir_cfg_in      = (unsigned int)strtoul(val, NULL, 0);
    else if (!strcmp(key, "ir_user1"))        t->ir_user1       = (unsigned int)strtoul(val, NULL, 0);
    else if (!strcmp(key, "ir_jprogram"))     t->ir_jprogram    = (unsigned int)strtoul(val, NULL, 0);
    else if (!strcmp(key, "ir_jstart"))       t->ir_jstart      = (unsigned int)strtoul(val, NULL, 0);
    else if (!strcmp(key, "ir_jshutdown"))    t->ir_jshutdown   = (unsigned int)strtoul(val, NULL, 0);
    else if (!strcmp(key, "ir_isc_disable"))  t->ir_isc_disable = (unsigned int)strtoul(val, NULL, 0);
    else if (!strcmp(key, "proxy_bitstream")) { free((void *)t->proxy_bitstream); t->proxy_bitstream = xstrdup(val); }
    else if (!strcmp(key, "caveats"))         t->caveats        = parse_caveats(val);
    else fprintf(stderr, "fpga: unknown key '%s'\n", key);
}

static int commit_entry(const fpga_target *cur)
{
    fpga_target *tmp = (fpga_target *)realloc(g_registry,
                                              (g_count + 1) * sizeof(*g_registry));
    if (!tmp) {
        fprintf(stderr, "fpga: out of memory loading registry\n");
        return -1;
    }
    g_registry = tmp;
    g_registry[g_count++] = *cur;
    return 0;
}

/* Walk the YAML event stream. The document is a mapping with a single
 * "fpgas" key holding a sequence of flat (scalar-only) mappings. */
static int load_registry(const char *path)
{
    FILE          *f;
    yaml_parser_t  parser;
    yaml_event_t   ev;
    int            done = 0;
    int            rc   = 0;

    int           in_fpgas         = 0;   /* inside the fpgas: sequence */
    int           in_item          = 0;   /* inside one entry mapping */
    int           expect_fpgas_seq = 0;   /* last top-level key was "fpgas" */
    char         *pending_key      = NULL;
    fpga_target   cur;

    f = fopen(path, "rb");
    if (!f) return -1;

    if (!yaml_parser_initialize(&parser)) { fclose(f); return -1; }
    yaml_parser_set_input_file(&parser, f);

    while (!done) {
        if (!yaml_parser_parse(&parser, &ev)) {
            fprintf(stderr, "fpga: YAML parse error in %s: %s (line %lu)\n",
                    path, parser.problem ? parser.problem : "?",
                    (unsigned long)parser.problem_mark.line + 1);
            rc = -1;
            break;
        }

        switch (ev.type) {
        case YAML_SCALAR_EVENT: {
            const char *v = (const char *)ev.data.scalar.value;
            if (!in_fpgas) {
                if (!strcmp(v, "fpgas"))
                    expect_fpgas_seq = 1;
            } else if (in_item) {
                if (!pending_key) {
                    pending_key = xstrdup(v);
                } else {
                    set_field(&cur, pending_key, v);
                    free(pending_key);
                    pending_key = NULL;
                }
            }
            break;
        }
        case YAML_SEQUENCE_START_EVENT:
            if (expect_fpgas_seq && !in_fpgas) {
                in_fpgas = 1;
                expect_fpgas_seq = 0;
            }
            break;
        case YAML_SEQUENCE_END_EVENT:
            if (in_fpgas && !in_item)
                in_fpgas = 0;             /* end of the fpgas list */
            break;
        case YAML_MAPPING_START_EVENT:
            if (in_fpgas && !in_item) {
                memset(&cur, 0, sizeof(cur));
                cur.idcode_mask = 0xFFFFFFFFUL;  /* safe default: exact match */
                in_item = 1;
            }
            break;
        case YAML_MAPPING_END_EVENT:
            if (in_item) {
                in_item = 0;
                free(pending_key);
                pending_key = NULL;
                if (commit_entry(&cur) != 0) {
                    rc = -1;
                    yaml_event_delete(&ev);
                    done = 1;
                    continue;
                }
            }
            break;
        case YAML_STREAM_END_EVENT:
            done = 1;
            break;
        default:
            break;
        }
        yaml_event_delete(&ev);
    }

    free(pending_key);
    yaml_parser_delete(&parser);
    fclose(f);
    return rc;
}

static void ensure_loaded(void)
{
    const char *path;

    if (g_loaded) return;
    g_loaded = 1;

    path = getenv("BS_FPGA_REGISTRY");
    if (!path || !*path) path = DEFAULT_REGISTRY_FILE;

    load_registry(path);   /* fills g_registry/g_count; warns on its own errors */

    if (g_count > 0) {
        strncpy(g_source, path, sizeof(g_source) - 1);
        g_source[sizeof(g_source) - 1] = '\0';
    } else {
        fprintf(stderr,
                "fpga: no targets loaded from '%s' "
                "(set BS_FPGA_REGISTRY, or run from the directory containing it)\n",
                path);
    }
}

/* ---- public API -------------------------------------------------- */

int fpga_get_target_count(void)
{
    ensure_loaded();
    return g_count;
}

const fpga_target *fpga_get_target_by_index(int index)
{
    ensure_loaded();
    if (index < 0 || index >= g_count) {
        return NULL;
    }
    return &g_registry[index];
}

const fpga_target *fpga_lookup_by_idcode(unsigned long idcode)
{
    int i;
    ensure_loaded();
    for (i = 0; i < g_count; i++) {
        const fpga_target *t = &g_registry[i];
        if ((idcode & t->idcode_mask) == (t->idcode & t->idcode_mask)) {
            return t;
        }
    }
    return NULL;
}

const char *fpga_family_name(fpga_family f)
{
    switch (f) {
    case FPGA_FAMILY_XILINX_7:                return "Xilinx 7-Series";
    case FPGA_FAMILY_XILINX_US:               return "Xilinx UltraScale";
    case FPGA_FAMILY_XILINX_USP:              return "Xilinx UltraScale+";
    case FPGA_FAMILY_MICROSEMI_IGLOO2:        return "Microsemi IGLOO2";
    case FPGA_FAMILY_MICROSEMI_SMARTFUSION2:  return "Microsemi SmartFusion2";
    case FPGA_FAMILY_LATTICE_MACHXO2:         return "Lattice MachXO2";
    case FPGA_FAMILY_LATTICE_MACHXO3:         return "Lattice MachXO3";
    case FPGA_FAMILY_UNKNOWN:
    default:                                  return "Unknown";
    }
}

const char *fpga_registry_source(void)
{
    ensure_loaded();
    return g_source[0] ? g_source : NULL;
}