#include <assert.h>
#include <string.h>

#include "http_entry.h"
#include "http_decoder_util.h"
#include "http_decoder_half.h"
#include "http_decoder_table.h"

#define HTTP_DECODER_RESULT_QUEUE_SIZE 16

#define HTTP_DECODER_IS_CACHE_LINE 1
#define HTTP_DECODER_IS_CACHE_BODY 1
#define HTTP_DECODER_IS_CACHE_HEADER 1

#define HTTP_DECODER_CONTEXT "HTTP_DECODER_CONTEXT"
#define HTTP_DECODER_RESULT "HTTP_DECODER_RESULT"

size_t http_decoder_context_index = session_register_ex_data_index(HTTP_DECODER_CONTEXT);
size_t http_decoder_result_index = session_register_ex_data_index(HTTP_DECODER_RESULT);

/******************************************************************************
 * struct define
 ******************************************************************************/

// per http session
struct http_decoder_result
{
    struct stellar_session *http_session; // pointer reference

    struct http_decoder_half_data *req_data;
    struct http_decoder_half_data *resp_data;

    const char *close_reason;
};

// per tcp session
struct http_decoder
{
    struct http_decoder_half *c2s_half;
    struct http_decoder_half *s2c_half;
};

struct http_decoder_result_queue
{
    size_t del_index;
    size_t req_index;
    size_t resp_index;
    size_t queue_size;
    struct http_decoder_result **array;
};

struct http_decoder_context
{
    struct stellar_session *tcp_session; // pointer reference

    struct http_decoder *decoder;
    struct http_decoder_result_queue *decoder_result_queue;

    int current_packet_have_trigger_req_hdr_event;
    int current_packet_have_trigger_resp_hdr_event;
};

static void http_event_handler(enum http_event event, struct http_decoder_half_data **data, void *cb_args);

static inline void http_decoder_context_free_cb(void *data, void *cb_arg);
static inline void http_decoder_result_free_cb(void *data, void *cb_arg);

/******************************************************************************
 * http_decoder_result API
 ******************************************************************************/

struct http_decoder_result *http_decoder_result_create()
{
    struct http_decoder_result *result = safe_alloc(struct http_decoder_result, 1);
    assert(result);

    result->http_session = NULL;
    result->close_reason = NULL;
    result->req_data = NULL;
    result->resp_data = NULL;

    // create half data on use
    // result->req_data = http_decoder_half_data_create();
    // result->resp_data = http_decoder_half_data_create();
    // assert(result->req_data);
    // assert(result->resp_data);

    return result;
}

void http_decoder_result_destory(struct http_decoder_result *result)
{
    if (result)
    {
        http_decoder_half_data_destory(result->req_data);
        http_decoder_half_data_destory(result->resp_data);

        result->http_session = NULL;
        result->close_reason = NULL;

        safe_free(result);
    }
}

/******************************************************************************
 * http_decoder_result_queue API
 ******************************************************************************/

static struct http_decoder_result_queue *http_decoder_result_queue_create(size_t queue_size)
{
    struct http_decoder_result_queue *queue = safe_alloc(struct http_decoder_result_queue, 1);
    assert(queue);

    queue->del_index = 0;
    queue->req_index = 0;
    queue->resp_index = 0;
    queue->queue_size = queue_size;

    queue->array = safe_alloc(struct http_decoder_result *, queue->queue_size);
    assert(queue->array);

    return queue;
}

static void http_decoder_result_queue_destory(struct http_decoder_result_queue *queue)
{
    if (queue)
    {
        if (queue->array)
        {
            for (size_t i = 0; i < queue->queue_size; i++)
            {
                struct http_decoder_result *result = queue->array[i];
                if (result)
                {
                    http_decoder_result_destory(result);
                }
            }
            safe_free(queue->array);
        }

        queue->del_index = 0;
        queue->req_index = 0;
        queue->resp_index = 0;
        queue->queue_size = 0;

        safe_free(queue);
    }
}

static void http_decoder_result_queue_reinit(struct http_decoder_result_queue *queue)
{
    assert(queue);

    queue->del_index = 0;
    queue->req_index = 0;
    queue->resp_index = 0;
    // queue->queue_size;

    for (size_t i = 0; i < queue->queue_size; i++)
    {
        struct http_decoder_result *result = queue->array[i];
        if (result)
        {
            http_decoder_result_destory(result);
        }
    }

    struct http_decoder_result **temp = queue->array;
    memset(queue->array, 0, sizeof(struct http_decoder_result *) * queue->queue_size);
    queue->array = temp;
}

static void http_decoder_result_queue_inc_req_index(struct http_decoder_result_queue *queue)
{
    assert(queue);

    queue->req_index++;
    queue->req_index = queue->req_index % queue->queue_size;
}

static void http_decoder_result_queue_inc_resp_index(struct http_decoder_result_queue *queue)
{
    assert(queue);

    queue->resp_index++;
    queue->resp_index = queue->resp_index % queue->queue_size;
}

static void http_decoder_result_queue_inc_del_index(struct http_decoder_result_queue *queue)
{
    assert(queue);

    queue->del_index++;
    queue->del_index = queue->del_index % queue->queue_size;
}

// Create a new http result and add it to the queue
static void http_decoder_result_queue_push(struct http_decoder_result_queue *queue, struct stellar_session *tcp_session, size_t index)
{
    assert(queue);
    assert(index >= 0 && index < queue->queue_size);

    if (queue->array[index] == NULL)
    {
        queue->array[index] = http_decoder_result_create();
        assert(queue->array[index]);

        queue->array[index]->http_session = session_derive(tcp_session, "HTTP");
        assert(queue->array[index]->http_session);
    }

    if (session_get_ex_data(queue->array[index]->http_session, http_decoder_result_index) == NULL)
    {
        session_set_ex_data(queue->array[index]->http_session, http_decoder_result_index, queue->array[index], http_decoder_result_free_cb, NULL);
    }
}

// Remove the http result from the queue but not destroy it
static void http_decoder_result_queue_pop(struct http_decoder_result_queue *queue, size_t index, const char *close_reason)
{
    assert(queue);
    assert(index >= 0 && index < queue->queue_size);

    if (queue->array[index])
    {
        queue->array[index]->close_reason = close_reason;
        session_trigger(queue->array[index]->http_session, "http.closing");
        queue->array[index] = NULL;
    }
}

// Remove old http result if queue is full
static void http_decoder_result_queue_gc(struct http_decoder_result_queue *queue, size_t index, const char *close_reason)
{
    assert(queue);
    assert(index >= 0 && index < queue->queue_size);

    if (index == queue->del_index)
    {
        http_decoder_result_queue_pop(queue, index, close_reason);
        http_decoder_result_queue_inc_del_index(queue);
    }
}

static struct stellar_session *http_decoder_result_queue_get_session(struct http_decoder_result_queue *queue, size_t index)
{
    assert(queue);
    assert(index >= 0 && index < queue->queue_size);

    return (queue->array[index] ? queue->array[index]->http_session : NULL);
}

/******************************************************************************
 * http_decoder API
 ******************************************************************************/

static struct http_decoder *http_decoder_create()
{
    struct http_decoder *decoder = safe_alloc(struct http_decoder, 1);
    assert(decoder);

    decoder->c2s_half = http_decoder_half_create();
    decoder->s2c_half = http_decoder_half_create();
    assert(decoder->c2s_half);
    assert(decoder->s2c_half);

    return decoder;
}

static void http_decoder_destory(struct http_decoder *decoder)
{
    if (decoder)
    {
        http_decoder_half_destory(decoder->c2s_half);
        http_decoder_half_destory(decoder->s2c_half);

        safe_free(decoder);
    }
}

static void http_decoder_reinit(struct http_decoder *decoder, void *args)
{
    assert(decoder);

    http_decoder_half_init(decoder->c2s_half, http_event_handler, args, HTTP_DECODER_IS_CACHE_LINE, HTTP_DECODER_IS_CACHE_HEADER, HTTP_DECODER_IS_CACHE_BODY);
    http_decoder_half_init(decoder->s2c_half, http_event_handler, args, HTTP_DECODER_IS_CACHE_LINE, HTTP_DECODER_IS_CACHE_HEADER, HTTP_DECODER_IS_CACHE_BODY);
}

/******************************************************************************
 * http_decoder_context API
 ******************************************************************************/

static struct http_decoder_context *http_decoder_context_create()
{
    struct http_decoder_context *ctx = safe_alloc(struct http_decoder_context, 1);
    assert(ctx);

    ctx->decoder = http_decoder_create();
    assert(ctx->decoder);

    ctx->decoder_result_queue = http_decoder_result_queue_create(HTTP_DECODER_RESULT_QUEUE_SIZE);
    assert(ctx->decoder_result_queue);

    ctx->tcp_session = NULL;

    return ctx;
}

static void http_decoder_context_destory(struct http_decoder_context *ctx)
{
    if (ctx)
    {
        http_decoder_result_queue_destory(ctx->decoder_result_queue);
        http_decoder_destory(ctx->decoder);

        safe_free(ctx);
    }
}

static void http_decoder_context_reinit(struct http_decoder_context *ctx)
{
    assert(ctx);

    http_decoder_reinit(ctx->decoder, ctx);
    http_decoder_result_queue_reinit(ctx->decoder_result_queue);
}

/******************************************************************************
 * free cb
 ******************************************************************************/

static inline void http_decoder_context_free_cb(void *data, void *cb_arg)
{
    http_decoder_context_destory((struct http_decoder_context *)data);
}

static inline void http_decoder_result_free_cb(void *data, void *cb_arg)
{
    http_decoder_result_destory((struct http_decoder_result *)data);
}

/******************************************************************************
 * http_decoder_entry
 ******************************************************************************/

/*
 * +-------+-------+-------+
 * | req1  | req2  | req3  |
 * +-------+-------+-------+
 * | resp1 | resp2 | resp3 |
 * +-------+-------+-------+
 *
 * case 1: req == null && resp == null
 * case 2: req == null && resp == part
 * case 3: req == null && resp == full
 *
 * case 4: req == part && resp == null
 * case 5: req == part && resp == part
 * case 6: req == part && resp == full
 *
 * case 7: req == full && resp == null
 * case 8: req == full && resp == part
 * case 9: req == full && resp == full
 */

static void http_event_handler(enum http_event event, struct http_decoder_half_data **data, void *cb_args)
{
    struct http_decoder_context *ctx = (struct http_decoder_context *)cb_args;
    assert(ctx);

    struct http_decoder_result_queue *queue = ctx->decoder_result_queue;
    assert(queue);

    // printf("event => %s\n", http_event_int2str(event));
    // http_decoder_half_data_dump(*data);

    struct stellar_session *req_session = http_decoder_result_queue_get_session(queue, queue->req_index);
    struct stellar_session *resp_session = http_decoder_result_queue_get_session(queue, queue->resp_index);

    switch (event)
    {
    case HTTP_EVENT_INIT:
        *data = http_decoder_half_data_create();
        break;
    case HTTP_EVENT_REQ_LINE:
        if (req_session == NULL)
        {
            http_decoder_result_queue_push(queue, ctx->tcp_session, queue->req_index);
            req_session = http_decoder_result_queue_get_session(queue, queue->req_index);
        }
        queue->array[queue->req_index]->req_data = *data;
        session_trigger(req_session, "http.opening");
        session_trigger(req_session, "http.req_line");
        break;
    case HTTP_EVENT_REQ_HDR:
        if (ctx->current_packet_have_trigger_req_hdr_event == 0)
        {
            session_trigger(req_session, "http.req_hdr");
            ctx->current_packet_have_trigger_req_hdr_event = 1;
        }
        break;
    case HTTP_EVENT_REQ_HDR_END:
        session_trigger(req_session, "http.req_hdr_end");
        break;
    case HTTP_EVENT_REQ_BODY_BEGIN:
        session_trigger(req_session, "http.req_body_begin");
        break;
    case HTTP_EVENT_REQ_BODY_DATA:
        session_trigger(req_session, "http.req_body_data");
        break;
    case HTTP_EVENT_REQ_BODY_END:
        session_trigger(req_session, "http.req_body_end");
        break;
    case HTTP_EVENT_REQ_END:
        session_trigger(req_session, "http.req_end");

        http_decoder_result_queue_inc_req_index(queue);
        http_decoder_result_queue_gc(queue, queue->req_index, "req queue full");
        *data = NULL;
        break;
    case HTTP_EVENT_RESP_LINE:
        // maybe only S2C traffic
        if (resp_session == NULL)
        {
            http_decoder_result_queue_push(queue, ctx->tcp_session, queue->resp_index);
            resp_session = http_decoder_result_queue_get_session(queue, queue->resp_index);

            session_trigger(resp_session, "http.opening");
        }
        queue->array[queue->resp_index]->req_data = *data;
        session_trigger(resp_session, "http.resp_line");
        break;
    case HTTP_EVENT_RESP_HDR:
        if (ctx->current_packet_have_trigger_resp_hdr_event == 0)
        {
            session_trigger(resp_session, "http.resp_hdr");
            ctx->current_packet_have_trigger_resp_hdr_event = 1;
        }
        break;
    case HTTP_EVENT_RESP_HDR_END:
        session_trigger(resp_session, "http.resp_hdr_end");
        break;
    case HTTP_EVENT_RESP_BODY_BEGIN:
        session_trigger(resp_session, "http.resp_body_begin");
        break;
    case HTTP_EVENT_RESP_BODY_DATA:
        session_trigger(resp_session, "http.resp_body_data");
        break;
    case HTTP_EVENT_RESP_BODY_END:
        session_trigger(resp_session, "http.resp_body_end");
        break;
    case HTTP_EVENT_RESP_END:
        session_trigger(resp_session, "http.resp_end");
        session_trigger(resp_session, "http.closing");

        http_decoder_result_queue_inc_resp_index(queue);
        http_decoder_result_queue_gc(queue, queue->resp_index, "resp queue full");
        *data = NULL;
        break;
    default:
        assert(0);
        break;
    }
}

void http_entry(struct stellar_session *tcp_session, const char *tcp_event, int thread_id)
{
    uint8_t tcp_dir = session_get_l4_dir(tcp_session);
    const char *payload = session_get_l4_payload(tcp_session);
    size_t payload_len = session_get_l4_payload_length(tcp_session);
    struct http_decoder_context *ctx = (struct http_decoder_context *)session_get_ex_data(tcp_session, http_decoder_context_index);

    if (strncmp("tcp.opening", tcp_event, strlen(tcp_event)) == 0)
    {
        // nothing
    }

    if (strncmp("tcp.order_pkt", tcp_event, strlen(tcp_event)) == 0)
    {
        // fist order pakcet on this tcp session
        if (ctx == NULL)
        {
            // not http protocol
            if (http_decoder_half_identify(payload, (payload_len > 16 ? 16 : payload_len)) == -1)
            {
                pm_session_dettach_me(tcp_session);
                return;
            }
            // is http protocol
            else
            {
                ctx = http_decoder_context_create();
                ctx->tcp_session = tcp_session;
                http_decoder_context_reinit(ctx);
                session_set_ex_data(ctx->tcp_session, http_decoder_context_index, ctx, http_decoder_context_free_cb, NULL);
            }
        }
        ctx->current_packet_have_trigger_req_hdr_event = 0;
        ctx->current_packet_have_trigger_resp_hdr_event = 0;

        struct http_decoder_result_queue *queue = ctx->decoder_result_queue;
        assert(queue);
        struct http_decoder_half *current_half = NULL;
        if (tcp_dir == SESSION_DIR_C2S)
        {
            current_half = ctx->decoder->c2s_half;
        }
        else
        {
            current_half = ctx->decoder->s2c_half;
        }

        if (http_decoder_half_parse(current_half, payload, payload_len) == -1)
        {
            if (tcp_dir == SESSION_DIR_C2S)
            {
                http_decoder_result_queue_pop(queue, queue->req_index, "c2s missing fragment");
            }
            else
            {
                http_decoder_result_queue_pop(queue, queue->resp_index, "c2s missing fragment");
            }

            const char *start_ptr = payload;
            const char *end_ptr = payload + payload_len;
            const char *target = NULL;
            while (start_ptr < end_ptr && (target = strstr(start_ptr, "\r\n\r\n")) != NULL)
            {
                start_ptr = target + 4;
                if (start_ptr < end_ptr && http_decoder_half_identify(start_ptr, end_ptr - start_ptr) == 0)
                {
                    http_decoder_half_init(current_half, http_event_handler, ctx, HTTP_DECODER_IS_CACHE_LINE, HTTP_DECODER_IS_CACHE_HEADER, HTTP_DECODER_IS_CACHE_BODY);
                    http_decoder_half_parse(current_half, start_ptr, end_ptr - start_ptr);
                    break;
                }
                else
                {
                    continue;
                }
            };
        }
    }

    if (strncmp("tcp.closing", tcp_event, strlen(tcp_event)) == 0)
    {
        if (ctx)
        {
            struct http_decoder_result_queue *queue = ctx->decoder_result_queue;
            assert(queue);

            // trigger http closing event on all sub http session
            for (size_t i = 0; i < queue->queue_size; i++)
            {
                http_decoder_result_queue_pop(queue, i, "tcp closing");
            }

            // free tcp session ctx
            session_del_ex_data(ctx->tcp_session, http_decoder_context_index);
            http_decoder_context_destory(ctx);
        }
    }
}

/******************************************************************************
 * Public API: For HTTP consumer
 ******************************************************************************/

void http_session_get_request_line(struct stellar_session *http_session, struct http_request_line *line)
{
    struct http_decoder_result *result = (struct http_decoder_result *)session_get_ex_data(http_session, http_decoder_result_index);
    assert(result);
    assert(line);

    http_decoder_table_get_method(result->req_data->table, (struct rstring *)&line->method);
    http_decoder_table_get_uri(result->req_data->table, (struct rstring *)&line->uri);
    http_decoder_table_get_version(result->req_data->table, (struct rstring *)&line->version);

    line->major_version = result->req_data->major_version;
    line->minor_version = result->req_data->minor_version;
}

void http_session_get_response_line(struct stellar_session *http_session, struct http_response_line *line)
{
    struct http_decoder_result *result = (struct http_decoder_result *)session_get_ex_data(http_session, http_decoder_result_index);
    assert(result);
    assert(line);

    http_decoder_table_get_version(result->resp_data->table, (struct rstring *)&line->version);
    http_decoder_table_get_status(result->resp_data->table, (struct rstring *)&line->status);

    line->major_version = result->resp_data->major_version;
    line->minor_version = result->resp_data->minor_version;
    line->status_code = result->resp_data->status_code;
}

void http_session_get_request_raw_body(struct stellar_session *http_session, struct http_string *body)
{
    struct http_decoder_result *result = (struct http_decoder_result *)session_get_ex_data(http_session, http_decoder_result_index);
    assert(result);
    assert(body);

    http_decoder_table_get_body(result->req_data->table, (struct rstring *)body);
}

void http_session_get_response_raw_body(struct stellar_session *http_session, struct http_string *body)
{
    struct http_decoder_result *result = (struct http_decoder_result *)session_get_ex_data(http_session, http_decoder_result_index);
    assert(result);
    assert(body);

    http_decoder_table_get_body(result->resp_data->table, (struct rstring *)body);
}

void http_session_get_request_decompress_body(struct stellar_session *http_session, struct http_string *body)
{
    struct http_decoder_result *result = (struct http_decoder_result *)session_get_ex_data(http_session, http_decoder_result_index);
    assert(result);
    assert(body);

    body->str = result->req_data->decompress_body;
    body->len = result->req_data->decompress_body_len;
}

void http_session_get_response_decompress_body(struct stellar_session *http_session, struct http_string *body)
{
    struct http_decoder_result *result = (struct http_decoder_result *)session_get_ex_data(http_session, http_decoder_result_index);
    assert(result);
    assert(body);

    body->str = result->resp_data->decompress_body;
    body->len = result->resp_data->decompress_body_len;
}

size_t http_session_get_request_header(struct stellar_session *http_session, struct http_string *header_key, struct http_string header_val[], size_t val_size)
{
    struct http_decoder_result *result = (struct http_decoder_result *)session_get_ex_data(http_session, http_decoder_result_index);
    assert(result);
    assert(header_key);
    assert(header_val);
    assert(val_size);

    return http_decoder_table_get_header(result->req_data->table, (struct rstring *)header_key, (struct rstring *)header_val, val_size);
}

size_t http_session_get_response_header(struct stellar_session *http_session, struct http_string *header_key, struct http_string header_val[], size_t val_size)
{
    struct http_decoder_result *result = (struct http_decoder_result *)session_get_ex_data(http_session, http_decoder_result_index);
    assert(result);
    assert(header_key);
    assert(header_val);
    assert(val_size);

    return http_decoder_table_get_header(result->resp_data->table, (struct rstring *)header_key, (struct rstring *)header_val, val_size);
}

void http_session_iter_request_header(struct stellar_session *http_session, size_t *iter_index, struct http_string *header_key, struct http_string *header_val)
{
    struct http_decoder_result *result = (struct http_decoder_result *)session_get_ex_data(http_session, http_decoder_result_index);
    assert(result);
    assert(iter_index);
    assert(header_key);
    assert(header_val);

    http_decoder_table_iter_header(result->req_data->table, iter_index, (struct rstring *)header_key, (struct rstring *)header_val);
}

void http_session_iter_response_header(struct stellar_session *http_session, size_t *iter_index, struct http_string *header_key, struct http_string *header_val)
{
    struct http_decoder_result *result = (struct http_decoder_result *)session_get_ex_data(http_session, http_decoder_result_index);
    assert(result);
    assert(iter_index);
    assert(header_key);
    assert(header_val);

    http_decoder_table_iter_header(result->resp_data->table, iter_index, (struct rstring *)header_key, (struct rstring *)header_val);
}