#ifndef APFL_CONTEXT_H
#define APFL_CONTEXT_H

#ifdef __cplusplus
extern "C" {
#endif

#include <stdint.h>
#include <setjmp.h>

#include "bytecode.h"
#include "hashmap.h"
#include "gc.h"
#include "value.h"
#include "scope.h"

#define RESULT_OFF_FOR_LONGJMP 1

struct scopes {
    // Both scope and closure_scope can be null
    struct scope *local;
    struct scope *closure;
};

struct matcher_capture_transfer {
    struct apfl_string *var;
    size_t path_start;
    size_t path_len;
    bool local;
};

struct matcher {
    struct matcher_instruction_list *instructions;
    size_t value_count;
    struct apfl_value *values;
};

struct stack {
    struct apfl_value *items;
    size_t len;
    size_t cap;
};

struct matcher_stack {
    struct matcher **items;
    size_t len;
    size_t cap;
};

struct func_call_stack_entry {
    size_t pc;
    struct instruction_list *instructions;

    // scopes.scope will be created lazily
    struct scopes scopes;

    size_t execution_line;

    struct function *function; // Can be NULL, in that case it's the toplevel
    size_t subfunction_index; // Not set, if function == NULL

    struct matcher_stack matcher_stack;
    bool returning_from_matcher;
    bool matcher_result;
};

struct cfunc_deferred {
    apfl_cfunc_defer_callback cb;
    void *opaque;
};

struct cfunc_call_stack_entry {
    struct cfunction *func;

    struct cfunc_deferred *deferred_list;
    size_t deferred_len;
    size_t deferred_cap;
};

enum matcher_mode {
    MATCHER_MODE_VALUE,
    MATCHER_MODE_STOP,
    MATCHER_MODE_LIST_START,
    MATCHER_MODE_LIST_END,
    MATCHER_MODE_LIST_REMAINING,
    MATCHER_MODE_LIST_UNDERFLOW,
    MATCHER_MODE_PAIR_L,
    MATCHER_MODE_PAIR_R,
};

struct matcher_state {
    enum matcher_mode mode;

    size_t lower;
    size_t upper;
};

struct matcher_call_stack_entry {
    size_t pc;
    bool from_predicate;
    struct matcher *matcher;
    struct scopes scopes;

    size_t capture_index;
    size_t capture_count;
    struct apfl_value *captures;
    struct matcher_capture_transfer *transfers;

    struct matcher_state *matcher_state_stack;
    size_t matcher_state_stack_len;
    size_t matcher_state_stack_cap;
};

struct func_dispatch_call_stack_entry {
    size_t subfunc;
    struct scopes scopes;
    bool returning_from_matcher;
    bool matcher_result;
    struct function *function;
};

struct call_stack_entry {
    enum apfl_call_stack_entry_type type;

    struct stack stack;

    union {
        struct func_call_stack_entry func;
        struct cfunc_call_stack_entry cfunc;
        struct matcher_call_stack_entry matcher;
        struct func_dispatch_call_stack_entry func_dispatch;
    };
};

struct call_stack {
    struct call_stack_entry *items;
    size_t len;
    size_t cap;
};

struct error_handler {
    jmp_buf jump;
};

struct iterative_runners_list {
    apfl_iterative_runner *items;
    size_t len;
    size_t cap;
};

struct apfl_ctx_data {
    struct gc gc;

    apfl_panic_callback panic_callback;
    void *panic_callback_data;

    struct stack toplevel_stack;

    struct scope *globals;
    struct call_stack call_stack;

    struct error_handler *error_handler;

    struct iterative_runners_list iterative_runners;

    struct apfl_io_writer output_writer;

    struct apfl_hashmap *registry;
};

void apfl_matcher_call_stack_entry_deinit(struct apfl_allocator, struct matcher_call_stack_entry *);
void apfl_call_stack_entry_deinit(struct apfl_allocator, struct call_stack_entry *);

void apfl_cfunc_run_deferred(apfl_ctx ctx, struct call_stack_entry *cse);

struct stack apfl_stack_new(void);

bool apfl_stack_push(apfl_ctx, struct apfl_value);
void apfl_stack_must_push(apfl_ctx ctx, struct apfl_value value);
bool apfl_stack_check_index(apfl_ctx, apfl_stackidx *);
bool apfl_stack_has_index(apfl_ctx, apfl_stackidx);
bool apfl_stack_pop(apfl_ctx, struct apfl_value *value, apfl_stackidx);
struct apfl_value apfl_stack_must_pop(apfl_ctx, apfl_stackidx);
bool apfl_stack_get(apfl_ctx, struct apfl_value *value, apfl_stackidx);
struct apfl_value apfl_stack_must_get(apfl_ctx, apfl_stackidx);
bool apfl_stack_drop(apfl_ctx, apfl_stackidx);
bool apfl_stack_drop_multi(apfl_ctx ctx, size_t count, apfl_stackidx *indices);
void apfl_stack_clear(apfl_ctx);
struct apfl_value *apfl_stack_push_placeholder(apfl_ctx);

// Like apfl_tostring, but ensures it's a dynamically allocated string and returns the underlying string.
struct apfl_string *apfl_to_dynamic_string(apfl_ctx ctx, apfl_stackidx index);

/* Raise an error with a message formatted according to fmt.
 *
 * fmt allows placeholders in the form of `{<param>:<type>}`, where `<param>:`
 * is optional. Each of these placeholders then takes a vararg. The following
 * placeholders are implemented:
 *
 * - string: Expects a `struct apfl_string_view` parameter and replaces the
 *   placeholder with that string. With the param `c`, a C `char *` string is
 *   expected instead.
 * - type: Expects an `enum apfl_type` and will replace the placeholder with the
 *   name of that type. With the param `value` a `struct apfl_value` is expected
 *   instead and the type of that value is used. With the param `stack` a
 *   `apfl_stackidx` is expected instead and the type of the value at the given
 *    stack index is used instead.
 */
noreturn void apfl_raise_errorfmt(apfl_ctx ctx, const char *fmt, ...);

struct call_stack_entry *apfl_call_stack_cur_entry(apfl_ctx);

struct scope *apfl_closure_scope_for_func(apfl_ctx, struct scopes);

struct apfl_io_writer apfl_get_output_writer(apfl_ctx);

enum apfl_result apfl_do_protected(
    apfl_ctx ctx,
    void (*callback)(apfl_ctx, void *),
    void *opaque,
    void (*errcallback)(apfl_ctx, void *)
);

bool apfl_ctx_register_iterative_runner(apfl_ctx, apfl_iterative_runner);
void apfl_ctx_unregister_iterative_runner(apfl_ctx, apfl_iterative_runner);

struct matcher *apfl_matcher_new(struct gc *, struct matcher_instruction_list *);
void apfl_matcher_deinit(struct apfl_allocator, struct matcher *);
void apfl_gc_matcher_traverse(struct matcher *, gc_visitor, void *);

void apfl_iterative_runner_visit_gc_objects(apfl_iterative_runner, gc_visitor, void *);

void apfl_load_bytecode(apfl_ctx, struct apfl_io_reader);

#ifdef __cplusplus
}
#endif

#endif