#ifndef MAZE32_MAZE_H
#define MAZE32_MAZE_H

#include <stddef.h>
#include <stdint.h>

#ifdef __cplusplus
extern "C" {
#endif

#define MAZE32_MAZE_MAX_WIDTH 32U
#define MAZE32_MAZE_MAX_HEIGHT 32U
#define MAZE32_MAZE_MAX_CELLS (MAZE32_MAZE_MAX_WIDTH * MAZE32_MAZE_MAX_HEIGHT)
#define MAZE32_MAZE_DEFAULT_WIDTH 32U
#define MAZE32_MAZE_DEFAULT_HEIGHT 32U
#define MAZE32_MAZE_MAX_LANDMARK_PAIRS 16U
#define MAZE32_MAZE_MAX_ARTIFACT_PAIRS 16U
#define MAZE32_MAZE_RAM_BUDGET_BYTES (64U * 1024U)
#define MAZE32_MAZE_RUNTIME_BUDGET_MS 250U

typedef enum {
    MAZE32_PASSAGE_NORTH = 1U << 0U,
    MAZE32_PASSAGE_EAST = 1U << 1U,
    MAZE32_PASSAGE_SOUTH = 1U << 2U,
    MAZE32_PASSAGE_WEST = 1U << 3U,
} maze32_passage_t;

typedef struct {
    uint16_t x;
    uint16_t y;
} maze32_cell_t;

typedef struct {
    uint16_t width;
    uint16_t height;
    uint8_t initial_view_radius;
    uint8_t cross_half_pairs;
    uint16_t extra_cycle_pairs;
    uint16_t minimum_exit_separation;
    uint8_t landmark_pairs;
    uint8_t artifact_pairs;
    uint8_t maximum_attempts;
} maze32_maze_config_t;

typedef struct {
    maze32_cell_t cells[2];
    uint8_t kind;
} maze32_landmark_pair_t;

typedef struct {
    maze32_maze_config_t config;
    uint32_t requested_seed;
    uint32_t generation_seed;
    uint8_t generation_attempts;
    uint8_t passages[MAZE32_MAZE_MAX_CELLS];
    maze32_cell_t starts[2];
    maze32_cell_t keys[2];
    maze32_cell_t exits[2];
    maze32_cell_t compasses[2];
    maze32_landmark_pair_t landmarks[MAZE32_MAZE_MAX_LANDMARK_PAIRS];
    maze32_cell_t artifacts[MAZE32_MAZE_MAX_ARTIFACT_PAIRS][2];
} maze32_maze_t;

typedef struct {
    uint8_t visited[(MAZE32_MAZE_MAX_CELLS + 7U) / 8U];
    uint16_t traversal[MAZE32_MAZE_MAX_CELLS];
    uint16_t distances[MAZE32_MAZE_MAX_CELLS];
} maze32_maze_workspace_t;

typedef struct {
    uint16_t reachable_cells;
    uint16_t passage_edges;
    uint16_t cycle_count;
    uint16_t dead_end_count;
    uint16_t branching_cells;
    uint16_t cross_half_connections;
    uint16_t start_to_key[2];
    uint16_t key_to_exit[2];
    uint16_t start_to_exit[2];
    uint16_t start_to_compass[2];
    uint32_t landmark_distance_total[2];
    uint32_t artifact_distance_total[2];
} maze32_maze_metrics_t;

typedef enum {
    MAZE32_MAZE_OK = 0,
    MAZE32_MAZE_INVALID_ARGUMENT,
    MAZE32_MAZE_INVALID_CONFIG,
    MAZE32_MAZE_UNREACHABLE,
    MAZE32_MAZE_ASYMMETRIC,
    MAZE32_MAZE_INSUFFICIENT_CYCLES,
    MAZE32_MAZE_INSUFFICIENT_CROSSINGS,
    MAZE32_MAZE_PLACEMENT_COLLISION,
    MAZE32_MAZE_UNFAIR_PLACEMENT,
    MAZE32_MAZE_KEY_IN_INITIAL_VIEW,
    MAZE32_MAZE_GENERATION_EXHAUSTED,
} maze32_maze_result_t;

typedef struct {
    maze32_maze_result_t result;
    maze32_maze_result_t last_validation_result;
    uint8_t attempts;
    maze32_maze_metrics_t metrics;
} maze32_maze_report_t;

maze32_maze_config_t maze32_maze_default_config(void);
maze32_maze_result_t maze32_maze_generate(maze32_maze_t* maze, maze32_maze_workspace_t* workspace,
                                          const maze32_maze_config_t* config, uint32_t seed,
                                          maze32_maze_report_t* report);
maze32_maze_result_t maze32_maze_validate(const maze32_maze_t* maze,
                                          maze32_maze_workspace_t* workspace,
                                          maze32_maze_metrics_t* metrics);
uint16_t maze32_maze_cell_index(const maze32_maze_t* maze, maze32_cell_t cell);
maze32_cell_t maze32_maze_rotate(const maze32_maze_t* maze, maze32_cell_t cell);
int maze32_maze_has_passage(const maze32_maze_t* maze, maze32_cell_t cell,
                            maze32_passage_t passage);
uint64_t maze32_maze_hash(const maze32_maze_t* maze);
const char* maze32_maze_result_name(maze32_maze_result_t result);

#ifdef __cplusplus
}
#endif

#endif