// SPDX-License-Identifier: GPL-2.0
#include <stdbool.h>
#include <assert.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include "metricgroup.h"
#include "debug.h"
#include "evlist.h"
#include "expr.h"
#include "smt.h"
#include "tool_pmu.h"
#include <util/expr-bison.h>
#include <util/expr-flex.h>
#include "util/hashmap.h"
#include "util/header.h"
#include "util/pmu.h"
#include <perf/cpumap.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/zalloc.h>
#include <ctype.h>
#include <math.h>

struct expr_id_data {
        union {
                struct {
                        double val;
                        int source_count;
                } val;
                struct {
                        double val;
                        const char *metric_name;
                        const char *metric_expr;
                } ref;
        };

        enum {
                /* Holding a double value. */
                EXPR_ID_DATA__VALUE,
                /* Reference to another metric. */
                EXPR_ID_DATA__REF,
                /* A reference but the value has been computed. */
                EXPR_ID_DATA__REF_VALUE,
        } kind;
};

static size_t key_hash(long key, void *ctx __maybe_unused)
{
        const char *str = (const char *)key;
        size_t hash = 0;

        while (*str != '\0') {
                hash *= 31;
                hash += *str;
                str++;
        }
        return hash;
}

static bool key_equal(long key1, long key2, void *ctx __maybe_unused)
{
        return !strcmp((const char *)key1, (const char *)key2);
}

struct hashmap *ids__new(void)
{
        struct hashmap *hash;

        hash = hashmap__new(key_hash, key_equal, NULL);
        if (IS_ERR(hash))
                return NULL;
        return hash;
}

void ids__free(struct hashmap *ids)
{
        struct hashmap_entry *cur;
        size_t bkt;

        if (ids == NULL)
                return;

        hashmap__for_each_entry(ids, cur, bkt) {
                zfree(&cur->pkey);
                zfree(&cur->pvalue);
        }

        hashmap__free(ids);
}

int ids__insert(struct hashmap *ids, const char *id)
{
        struct expr_id_data *data_ptr = NULL, *old_data = NULL;
        char *old_key = NULL;
        int ret;

        ret = hashmap__set(ids, id, data_ptr, &old_key, &old_data);
        if (ret)
                free(data_ptr);
        free(old_key);
        free(old_data);
        return ret;
}

struct hashmap *ids__union(struct hashmap *ids1, struct hashmap *ids2)
{
        size_t bkt;
        struct hashmap_entry *cur;
        int ret;
        struct expr_id_data *old_data = NULL;
        char *old_key = NULL;

        if (!ids1)
                return ids2;

        if (!ids2)
                return ids1;

        if (hashmap__size(ids1) <  hashmap__size(ids2)) {
                struct hashmap *tmp = ids1;

                ids1 = ids2;
                ids2 = tmp;
        }
        hashmap__for_each_entry(ids2, cur, bkt) {
                ret = hashmap__set(ids1, cur->key, cur->value, &old_key, &old_data);
                free(old_key);
                free(old_data);

                if (ret) {
                        hashmap__free(ids1);
                        hashmap__free(ids2);
                        return NULL;
                }
        }
        hashmap__free(ids2);
        return ids1;
}

/* Caller must make sure id is allocated */
int expr__add_id(struct expr_parse_ctx *ctx, const char *id)
{
        return ids__insert(ctx->ids, id);
}

/* Caller must make sure id is allocated */
int expr__add_id_val(struct expr_parse_ctx *ctx, const char *id, double val)
{
        return expr__add_id_val_source_count(ctx, id, val, /*source_count=*/1);
}

/* Caller must make sure id is allocated */
int expr__add_id_val_source_count(struct expr_parse_ctx *ctx, const char *id,
                                  double val, int source_count)
{
        struct expr_id_data *data_ptr = NULL, *old_data = NULL;
        char *old_key = NULL;
        int ret;

        data_ptr = malloc(sizeof(*data_ptr));
        if (!data_ptr)
                return -ENOMEM;
        data_ptr->val.val = val;
        data_ptr->val.source_count = source_count;
        data_ptr->kind = EXPR_ID_DATA__VALUE;

        ret = hashmap__set(ctx->ids, id, data_ptr, &old_key, &old_data);
        if (ret) {
                free(data_ptr);
        } else if (old_data) {
                data_ptr->val.val += old_data->val.val;
                data_ptr->val.source_count += old_data->val.source_count;
        }
        free(old_key);
        free(old_data);
        return ret;
}

int expr__add_ref(struct expr_parse_ctx *ctx, struct metric_ref *ref)
{
        struct expr_id_data *data_ptr = NULL, *old_data = NULL;
        char *old_key = NULL;
        char *name;
        int ret;

        data_ptr = zalloc(sizeof(*data_ptr));
        if (!data_ptr)
                return -ENOMEM;

        name = strdup(ref->metric_name);
        if (!name) {
                free(data_ptr);
                return -ENOMEM;
        }

        /*
         * Intentionally passing just const char pointers,
         * originally from 'struct pmu_event' object.
         * We don't need to change them, so there's no
         * need to create our own copy.
         */
        data_ptr->ref.metric_name = ref->metric_name;
        data_ptr->ref.metric_expr = ref->metric_expr;
        data_ptr->kind = EXPR_ID_DATA__REF;

        ret = hashmap__set(ctx->ids, name, data_ptr, &old_key, &old_data);
        if (ret)
                free(data_ptr);

        pr_debug2("adding ref metric %s: %s\n",
                  ref->metric_name, ref->metric_expr);

        free(old_key);
        free(old_data);
        return ret;
}

int expr__get_id(struct expr_parse_ctx *ctx, const char *id,
                 struct expr_id_data **data)
{
        if (!ctx || !id)
                return -1;
        return hashmap__find(ctx->ids, id, data) ? 0 : -1;
}

bool expr__subset_of_ids(struct expr_parse_ctx *haystack,
                         struct expr_parse_ctx *needles)
{
        struct hashmap_entry *cur;
        size_t bkt;
        struct expr_id_data *data;

        hashmap__for_each_entry(needles->ids, cur, bkt) {
                if (expr__get_id(haystack, cur->pkey, &data))
                        return false;
        }
        return true;
}


int expr__resolve_id(struct expr_parse_ctx *ctx, const char *id,
                     struct expr_id_data **datap)
{
        struct expr_id_data *data;

        if (expr__get_id(ctx, id, datap) || !*datap) {
                pr_debug("%s not found\n", id);
                return -1;
        }

        data = *datap;

        switch (data->kind) {
        case EXPR_ID_DATA__VALUE:
                pr_debug2("lookup(%s): val %f\n", id, data->val.val);
                break;
        case EXPR_ID_DATA__REF:
                pr_debug2("lookup(%s): ref metric name %s\n", id,
                        data->ref.metric_name);
                pr_debug("processing metric: %s ENTRY\n", id);
                data->kind = EXPR_ID_DATA__REF_VALUE;
                if (expr__parse(&data->ref.val, ctx, data->ref.metric_expr)) {
                        pr_debug("%s failed to count\n", id);
                        return -1;
                }
                pr_debug("processing metric: %s EXIT: %f\n", id, data->ref.val);
                break;
        case EXPR_ID_DATA__REF_VALUE:
                pr_debug2("lookup(%s): ref val %f metric name %s\n", id,
                        data->ref.val, data->ref.metric_name);
                break;
        default:
                assert(0);  /* Unreachable. */
        }

        return 0;
}

void expr__del_id(struct expr_parse_ctx *ctx, const char *id)
{
        struct expr_id_data *old_val = NULL;
        char *old_key = NULL;

        hashmap__delete(ctx->ids, id, &old_key, &old_val);
        free(old_key);
        free(old_val);
}

struct expr_parse_ctx *expr__ctx_new(void)
{
        struct expr_parse_ctx *ctx;

        ctx = calloc(1, sizeof(struct expr_parse_ctx));
        if (!ctx)
                return NULL;

        ctx->ids = hashmap__new(key_hash, key_equal, NULL);
        if (IS_ERR(ctx->ids)) {
                free(ctx);
                return NULL;
        }

        return ctx;
}

void expr__ctx_clear(struct expr_parse_ctx *ctx)
{
        struct hashmap_entry *cur;
        size_t bkt;

        hashmap__for_each_entry(ctx->ids, cur, bkt) {
                zfree(&cur->pkey);
                zfree(&cur->pvalue);
        }
        hashmap__clear(ctx->ids);
}

void expr__ctx_free(struct expr_parse_ctx *ctx)
{
        struct hashmap_entry *cur;
        size_t bkt;

        if (!ctx)
                return;

        zfree(&ctx->sctx.user_requested_cpu_list);
        hashmap__for_each_entry(ctx->ids, cur, bkt) {
                zfree(&cur->pkey);
                zfree(&cur->pvalue);
        }
        hashmap__free(ctx->ids);
        free(ctx);
}

static int
__expr__parse(double *val, struct expr_parse_ctx *ctx, const char *expr,
              bool compute_ids)
{
        YY_BUFFER_STATE buffer;
        void *scanner;
        int ret;

        pr_debug2("parsing metric: %s\n", expr);

        ret = expr_lex_init_extra(&ctx->sctx, &scanner);
        if (ret)
                return ret;

        buffer = expr__scan_string(expr, scanner);

#ifdef PARSER_DEBUG
        expr_debug = 1;
        expr_set_debug(1, scanner);
#endif

        ret = expr_parse(val, ctx, compute_ids, scanner);

        expr__flush_buffer(buffer, scanner);
        expr__delete_buffer(buffer, scanner);
        expr_lex_destroy(scanner);
        return ret;
}

int expr__parse(double *final_val, struct expr_parse_ctx *ctx,
                const char *expr)
{
        return __expr__parse(final_val, ctx, expr, /*compute_ids=*/false) ? -1 : 0;
}

int expr__find_ids(const char *expr, const char *one,
                   struct expr_parse_ctx *ctx)
{
        int ret = __expr__parse(NULL, ctx, expr, /*compute_ids=*/true);

        if (one)
                expr__del_id(ctx, one);

        return ret;
}

double expr_id_data__value(const struct expr_id_data *data)
{
        if (data->kind == EXPR_ID_DATA__VALUE)
                return data->val.val;
        assert(data->kind == EXPR_ID_DATA__REF_VALUE);
        return data->ref.val;
}

double expr_id_data__source_count(const struct expr_id_data *data)
{
        assert(data->kind == EXPR_ID_DATA__VALUE);
        return data->val.source_count;
}

double expr__get_literal(const char *literal, const struct expr_scanner_ctx *ctx)
{
        double result = NAN;
        enum tool_pmu_event ev = tool_pmu__str_to_event(literal + 1);

        if (ev != TOOL_PMU__EVENT_NONE) {
                u64 count;

                if (tool_pmu__read_event(ev, /*evsel=*/NULL,
                                         ctx->system_wide, ctx->user_requested_cpu_list,
                                         &count))
                        result = count;
                else
                        pr_err("Failure to read '%s'", literal);
        } else {
                pr_err("Unrecognized literal '%s'", literal);
        }

        pr_debug2("literal: %s = %f\n", literal, result);
        return result;
}

/* Does the event 'id' parse? Determine via ctx->ids if possible. */
double expr__has_event(const struct expr_parse_ctx *ctx, bool compute_ids, const char *id)
{
        struct evlist *tmp;
        double ret;

        if (hashmap__find(ctx->ids, id, /*value=*/NULL))
                return 1.0;

        if (!compute_ids)
                return 0.0;

        tmp = evlist__new();
        if (!tmp)
                return NAN;

        if (strchr(id, '@')) {
                char *tmp_id, *p;

                tmp_id = strdup(id);
                if (!tmp_id) {
                        ret = NAN;
                        goto out;
                }
                p = strchr(tmp_id, '@');
                *p = '/';
                p = strrchr(tmp_id, '@');
                *p = '/';
                ret = parse_event(tmp, tmp_id) ? 0 : 1;
                free(tmp_id);
        } else {
                ret = parse_event(tmp, id) ? 0 : 1;
        }
out:
        evlist__delete(tmp);
        return ret;
}

double expr__strcmp_cpuid_str(const struct expr_parse_ctx *ctx __maybe_unused,
                       bool compute_ids __maybe_unused, const char *test_id)
{
        double ret;
        struct perf_cpu cpu = {-1};
        char *cpuid = get_cpuid_allow_env_override(cpu);

        if (!cpuid)
                return NAN;

        ret = !strcmp_cpuid_str(test_id, cpuid);

        free(cpuid);
        return ret;
}