#include <stdio.h>
#include <string.h>
#include <errno.h>
#include "sector.h"

#define VERTS_CAP 512
#define SECTS_CAP 512
#define NUMS_CAP  512
#define MAX_QUEUE 32

#define hfov (0.73f*SH)  // Affects the horizontal field of vision
#define vfov (.2f*SH)    // Affects the vertical field of vision

void vline(int x, int y1, int y2, uint32_t col);

int map_draw(map_t *map, uint SW, uint SH)
{
    int ytop[SW], ybottom[SW];
    for(uint i = 0; i < SW; i++) {
        ytop[i] = 0;
        ybottom[i] = SH-1;
    }

    struct { int sx1, sx2 } now = {0, SW-1};
    struct sector *sect = &map->sectors[map->player.sector];

    for(size_t i = 0; i < sect->nverts; i++)
    {
        map->player.pos.z = sect->floor + 6; //temp

        size_t s0 = sect->vertices[i], s1 = sect->vertices[i+1];

        float vx1 = map->vertices[s0].x - map->player.pos.x, vy1 = map->vertices[s0].y - map->player.pos.y;
        float vx2 = map->vertices[s1].x - map->player.pos.x, vy2 = map->vertices[s1].y - map->player.pos.y;

        float pcos = map->player.anglecos,   psin = map->player.anglesin;
        float tx1 = vx1 * psin - vy1 * pcos, tz1 = vx1 * pcos + vy1 * psin;
        float tx2 = vx2 * psin - vy2 * pcos, tz2 = vx2 * pcos + vy2 * psin;

        if(tz1 <= 0 && tz2 <= 0) continue;

        // ??? magic
        if(tz1 <= 0 || tz2 <= 0)
        {
            float nearz = 1e-4f, farz = 5, nearside = 1e-5f, farside = 20.f;
            // Find an intersection between the wall and the approximate edges of player's view
            struct xy i1 = intersect(tx1,tz1,tx2,tz2, -nearside,nearz, -farside,farz);
            struct xy i2 = intersect(tx1,tz1,tx2,tz2,  nearside,nearz,  farside,farz);
            if(tz1 < nearz) { if(i1.y > 0) { tx1 = i1.x; tz1 = i1.y; } else { tx1 = i2.x; tz1 = i2.y; } }
            if(tz2 < nearz) { if(i1.y > 0) { tx2 = i1.x; tz2 = i1.y; } else { tx2 = i2.x; tz2 = i2.y; } }
        }

        float xscale1 = hfov / tz1, yscale1 = vfov / tz1;    int x1 = SW/2 - (int)(tx1 * xscale1);
        float xscale2 = hfov / tz2, yscale2 = vfov / tz2;    int x2 = SW/2 - (int)(tx2 * xscale2);
        if(x1 >= x2 || x2 < now.sx1 || x1 > now.sx2) continue; // Only render if it's visible
        /* Acquire the floor and ceiling heights, relative to where the player's view is */
        float yceil  = sect->ceil  - map->player.pos.z;
        float yfloor = sect->floor - map->player.pos.z;

        size_t neighbor = sect->neighbors[i];

        int y1a  = SH/2 - (int)(yceil * yscale1),  y1b = SH/2 - (int)(yfloor * yscale1);
        int y2a  = SH/2 - (int)(yceil * yscale2),  y2b = SH/2 - (int)(yfloor * yscale2);

        int beginx = max(x1, now.sx1), endx = min(x2, now.sx2);
        for(int x = beginx; x <= endx; ++x)
        {
            // int z = ((x - x1) * (tz2-tz1) / (x2-x1) + tz1) * 8;
            /* Acquire the Y coordinates for our ceiling & floor for this X coordinate. Clamp them. */
            int ya = (x - x1) * (y2a-y1a) / (x2-x1) + y1a, cya = clamp(ya, ytop[x],ybottom[x]); // top
            int yb = (x - x1) * (y2b-y1b) / (x2-x1) + y1b, cyb = clamp(yb, ytop[x],ybottom[x]); // bottom

            /* Render ceiling: everything above this sector's ceiling height. */
            vline(x, ytop[x], cya-1, COLOR_GREEN);
            /* Render floor: everything below this sector's floor height. */
            vline(x, cyb+1, ybottom[x], COLOR_BLUE);

            if(neighbor == (size_t)-1)
            {
                // vline(x, cya, cyb, x==x1||x==x2 ? COLOR_LIGHTWHITE : COLOR_WHITE);
                vline(x, cya, cyb, COLOR_WHITE);
            }
            else
            {
                vline(x, cya, cyb, COLOR_RED);
            }
        }
    }
    return 0;
}

int map_load(map_t *map, char *filename)
{
    int ret = 1;

    FILE *fp = fopen(filename, "rb");
    if(!fp) {
        log_critical(LOG_SYSTEM, "fopen (%s): %s\n", filename, strerror(errno));
        return ret;
    }

    // temp structures
    struct xy vertices[VERTS_CAP];
    size_t verts = 0;
    struct sector sectors[SECTS_CAP];
    size_t sects = 0;
    player_t player = {0};

    char line[512], *ptr;
    int offset = 0;
    while(fgets(line, sizeof(line), fp) != NULL)
    {
        char word[256] = {0};
        if(sscanf(ptr = line, "%s %n", word, &offset) != 1) word[0] = '\0';

        switch(word[0])
        {
        case 'v':; // vertex
            struct xy vert;
            sscanf(ptr += offset, "%f %n", &vert.x, &offset);

            while(sscanf(ptr += offset, "%f %n", &vert.y, &offset) != EOF) {
                if(verts >= VERTS_CAP) {
                    log_critical(LOG_APPLICATION, "VERTS_CAP of %d reached", VERTS_CAP);
                    goto exit;
                }
                vertices[verts++] = vert;
            }
            break;
        case 's': // sector
            if(sects >= SECTS_CAP) {
                log_critical(LOG_APPLICATION, "SECTS_CAP of %d reached", SECTS_CAP);
                goto exit;
            }

            sscanf(ptr += offset, "%f %f %n", &sectors[sects].floor, &sectors[sects].ceil, &offset);

            size_t numbers[NUMS_CAP];
            size_t nums = 0;
            while(sscanf(ptr += offset, "%s %n", word, &offset) != EOF) {
                if(nums >= NUMS_CAP) {
                    log_critical(LOG_APPLICATION, "NUMS_CAP of %d reached", NUMS_CAP);
                    goto exit;
                }

                numbers[nums++] = (word[0] == 'x') ? -1 : atoi(word);
            }

            size_t nverts = nums/2;
            // populate vertices
            sectors[sects].vertices = malloc((nverts + 1) * sizeof(*sectors[sects].vertices));
            for(size_t i = 0; i < nverts; i++)
                sectors[sects].vertices[i+1] = numbers[i];
            sectors[sects].vertices[0] = sectors[sects].vertices[nverts]; // need to form a loop

            // populate neighbors
            sectors[sects].neighbors = malloc(nverts * sizeof(*sectors[sects].neighbors));
            for(size_t i = 0; i < nverts; i++)
                sectors[sects].neighbors[i] = numbers[nverts + i];

            sectors[sects++].nverts = nverts;
            break;
        case 'p': // player
            sscanf(ptr += offset, "%f %f %f %zu %n", &player.pos.x, &player.pos.y, &player.angle, &player.sector, &offset);
            break;
        }
    }

    map->sectors = malloc(sects * sizeof(*sectors));
    map->nsects = sects;
    memcpy(map->sectors, sectors, sects * sizeof(*sectors));

    map->vertices = malloc(verts * sizeof(*vertices));
    map->nverts = verts;
    memcpy(map->vertices, vertices, verts * sizeof(*vertices));

    map->player = player;

    ret = 0;
exit:
    fclose(fp);
    return ret;
}

void map_unload(map_t *map)
{
    for(size_t i = 0; i < map->nsects; i++) {
        free(map->sectors[i].vertices);
        free(map->sectors[i].neighbors);
    }

    free(map->sectors);
    free(map->vertices);
}

int map_save(map_t *map, char *filename)
{
    FILE *fp = fopen(filename, "wb");
    if(!fp) {
        log_error(LOG_SYSTEM, "fopen (%s): %s\n", filename, strerror(errno));
        return 1;
    }

    (void)map;

    // something something

    return 0;
}

void map_print(map_t *map)
{
    log("%zu %zu", map->nverts, map->nsects);
    for(size_t i = 0; i < map->nverts; i++) {
        printf("v %zu {%.1f %.1f}\n", i, map->vertices[i].x, map->vertices[i].y);
    }

    for(size_t i = 0; i < map->nsects; i++)
    {
        printf("s %zu  %.1f %.1f  ", i, map->sectors[i].floor, map->sectors[i].ceil);

        for(size_t j = 0; j < map->sectors[i].nverts + 1; j++)
            printf("%zu ", map->sectors[i].vertices[j]);
        printf("  ");

        for(size_t j = 0; j < map->sectors[i].nverts; j++)
            printf("%zu ", map->sectors[i].neighbors[j]);
        printf("\n");
    }

    printf("p %.1f %.1f %.1f %zu", map->player.pos.x, map->player.pos.y, map->player.angle, map->player.sector);
}