#include <memory.h>
#include "malunal/containers/vector.h"


typedef struct {
  object_t    object;
  container_t container;

  allocator_mptr_t allocator;
  malunal_size_t   stride;
  malunal_size_t   count;
  malunal_size_t   capacity;
  malunal_mptr_t   buffer;
} impl_t;

typedef       impl_t* impl_mptr_t;
typedef const impl_t* impl_iptr_t;
_Static_assert(
  sizeof(vector_container_t) == sizeof(impl_t),
  "Vector container must be the size of its implementation"
);


static
error_t
vector_object_cast_impl(
  malunal_mptr_t  object,
  uuid_iptr_t     uuid,
  malunal_mptr_t* out
) {
  if (object == null)
    return (error_t) {
      .domain = &ERROR_DOMAIN_CONTAINER_T,
      .code   = CONTAINER_ERROR_NULL_CONTAINER
    };

  impl_mptr_t self = (impl_mptr_t)object;
  if (uuid_equals(&UUID_OBJECT_T, uuid)) {
    *out = &self->object;
    return NO_ERROR;
  }

  if (uuid_equals(&UUID_CONTAINER_T, uuid)) {
    *out = &self->container;
    return NO_ERROR;
  }

  *out = null;
  return (error_t) {
    .domain = &ERROR_DOMAIN_CONTAINER_T,
    .code   = CONTAINER_ERROR_FAILURE
  };
}

static
malunal_uint32_t
vector_object_retain_impl(
  malunal_mptr_t object
) {
  // TODO: figure out how to handle this.
}

static
malunal_uint32_t
vector_object_release_impl(
  malunal_mptr_t object
) {
  // TODO: figure out how to handle this.
}

static const
object_vtable_t vector_object_vtable = {
  .cast    = &vector_object_cast_impl,
  .retain  = &vector_object_retain_impl,
  .release = &vector_object_release_impl
};

static const
container_vtable_t vector_container_vtable = {
  .allocator = (container_allocator_pfn_t)&vector_container_allocator,
  .stride    = (container_stride_pfn_t)&vector_container_stride,
  .count     = (container_count_pfn_t)&vector_container_count,
  .capacity  = (container_capacity_pfn_t)&vector_container_capacity,
  .append    = (container_append_pfn_t)&vector_container_append,
  .remove    = (container_remove_pfn_t)&vector_container_remove,
  .contains  = (container_contains_pfn_t)&vector_container_contains,
  .clear     = (container_clear_pfn_t)&vector_container_clear
};

static
error_t
vector_container_realloc(impl_mptr_t self) {
  if ((float)self->count / self->capacity < 0.75f)
    return NO_ERROR;

  malunal_mptr_t buffer;
  malunal_size_t oldcap = self->stride * self->capacity;
  error_t        result = allocator_acquire(self->allocator, oldcap * 2, &buffer);
  if (result.domain != null)
    return result;

  buffer = memmove(buffer, self->buffer, oldcap);
  result = allocator_dispose(self->allocator, self->buffer, oldcap);
  self->buffer   = buffer;
  self->capacity = self->capacity * 2;
  return NO_ERROR;
}

error_t
vector_container_init(
  malunal_size_t          stride,
  malunal_size_t          capacity,
  allocator_mptr_t        allocator,
  vector_container_mptr_t vector
) {
  if (vector == null)
    return (error_t) {
      .domain = &ERROR_DOMAIN_CONTAINER_T,
      .code   = CONTAINER_ERROR_NULL_CONTAINER
    };

  impl_mptr_t self   = (impl_mptr_t)vector;
  error_t     result = allocator_acquire(
    allocator,
    stride * capacity,
    &self->buffer
  );

  if (result.domain != null)
    return result;

  self->object    = (object_t)   { &vector_object_vtable    };
  self->container = (container_t){ &vector_container_vtable };
  self->allocator = allocator;
  self->stride    = stride;
  self->count     = 0;
  self->capacity  = capacity;
  return NO_ERROR;
}

error_t
vector_container_free(
  vector_container_mptr_t vector
) {
  if (vector == null)
    return (error_t) {
      .domain = &ERROR_DOMAIN_CONTAINER_T,
      .code   = CONTAINER_ERROR_NULL_CONTAINER
    };

  impl_mptr_t self   = (impl_mptr_t)vector;
  error_t     result = allocator_dispose(
    self->allocator,
    self->buffer,
    self->stride * self->capacity
  );

  if (result.domain != null)
    return result;

  self->stride   = 0;
  self->count    = 0;
  self->capacity = 0;
  self->buffer   = null;
  return NO_ERROR;
}

error_t
vector_container_allocator(
  vector_container_iptr_t vector,
  allocator_mptr_t*       out
) {
  if (vector == null)
    return (error_t) {
      .domain = &ERROR_DOMAIN_CONTAINER_T,
      .code   = CONTAINER_ERROR_NULL_CONTAINER
    };

  impl_iptr_t self = (impl_iptr_t)vector;
  *out = self->allocator;
  return NO_ERROR;
}

error_t
vector_container_stride(
  vector_container_iptr_t vector,
  malunal_size_t*         out
) {
  if (vector == null)
    return (error_t) {
      .domain = &ERROR_DOMAIN_CONTAINER_T,
      .code   = CONTAINER_ERROR_NULL_CONTAINER
    };

  impl_iptr_t self = (impl_iptr_t)vector;
  *out = self->stride;
  return NO_ERROR;
}

error_t
vector_container_count(
  vector_container_iptr_t vector,
  malunal_size_t*         out
) {
  if (vector == null)
    return (error_t) {
      .domain = &ERROR_DOMAIN_CONTAINER_T,
      .code   = CONTAINER_ERROR_NULL_CONTAINER
    };

  impl_iptr_t self = (impl_iptr_t)vector;
  *out = self->count;
  return NO_ERROR;
}

error_t
vector_container_capacity(
  vector_container_iptr_t vector,
  malunal_size_t*         out
) {
  if (vector == null)
    return (error_t) {
      .domain = &ERROR_DOMAIN_CONTAINER_T,
      .code   = CONTAINER_ERROR_NULL_CONTAINER
    };

  impl_iptr_t self = (impl_iptr_t)vector;
  *out = self->capacity;
  return NO_ERROR;
}

error_t
vector_container_append(
  vector_container_mptr_t vector,
  malunal_iptr_t          element
) {
  if (vector == null)
    return (error_t) {
      .domain = &ERROR_DOMAIN_CONTAINER_T,
      .code   = CONTAINER_ERROR_NULL_CONTAINER
    };

  impl_mptr_t self   = (impl_mptr_t)vector;
  error_t     result = vector_container_realloc(self);
  if (result.domain != null)
    return result;

  malunal_uint8_t* buffer = self->buffer;
  buffer += self->stride * self->count;
  memcpy(buffer, element, self->stride);
  self->count++;
  return NO_ERROR;
}

error_t
vector_container_remove(
  vector_container_mptr_t vector,
  malunal_iptr_t          element
) {
  if (vector == null)
    return (error_t) {
      .domain = &ERROR_DOMAIN_CONTAINER_T,
      .code   = CONTAINER_ERROR_NULL_CONTAINER
    };

  malunal_size_t index;
  impl_mptr_t    self   = (impl_mptr_t)vector;
  error_t        result = vector_container_index_of(vector, element, &index);
  if (result.domain != null)
    return result;

  return index != (malunal_size_t)-1
   ? vector_container_remove_at(vector, index)
   : NO_ERROR;
}

error_t
vector_container_contains(
  vector_container_iptr_t vector,
  malunal_iptr_t          element
) {
  if (vector == null)
    return (error_t) {
      .domain = &ERROR_DOMAIN_CONTAINER_T,
      .code   = CONTAINER_ERROR_NULL_CONTAINER
    };

  malunal_size_t index;
  impl_iptr_t    self   = (impl_iptr_t)vector;
  error_t        result = vector_container_index_of(vector, element, &index);
  if (result.domain != null)
    return result;

  return index == (malunal_size_t)-1
    ? (error_t) {
        .domain = &ERROR_DOMAIN_CONTAINER_T,
        .code   = CONTAINER_ERROR_FAILURE
      }
    : NO_ERROR;
}

error_t
vector_container_clear(
  vector_container_mptr_t vector
) {
  if (vector == null)
    return (error_t) {
      .domain = &ERROR_DOMAIN_CONTAINER_T,
      .code   = CONTAINER_ERROR_NULL_CONTAINER
    };

  impl_mptr_t self = (impl_mptr_t)vector;
  self->count = 0;
  return NO_ERROR;
}

error_t
vector_container_get(
  vector_container_iptr_t vector,
  malunal_size_t          index,
  malunal_mptr_t          element
) {
  if (vector == null)
    return (error_t) {
      .domain = &ERROR_DOMAIN_CONTAINER_T,
      .code   = CONTAINER_ERROR_NULL_CONTAINER
    };

  impl_iptr_t self = (impl_iptr_t)vector;
  if (index >= self->count)
    return (error_t) {
      .domain = &ERROR_DOMAIN_CONTAINER_T,
      .code   = CONTAINER_ERROR_OUT_OF_BOUNDS
    };

  malunal_uint8_t* buffer = self->buffer;
  buffer += self->stride * index;
  memcpy(element, buffer, self->stride);
  return NO_ERROR;
}

error_t
vector_container_set(
  vector_container_mptr_t vector,
  malunal_size_t          index,
  malunal_iptr_t          element
) {
  if (vector == null)
    return (error_t) {
      .domain = &ERROR_DOMAIN_CONTAINER_T,
      .code   = CONTAINER_ERROR_NULL_CONTAINER
    };

  impl_mptr_t self = (impl_mptr_t)vector;
  if (index >= self->count)
    return (error_t) {
      .domain = &ERROR_DOMAIN_CONTAINER_T,
      .code   = CONTAINER_ERROR_OUT_OF_BOUNDS
    };

  malunal_uint8_t* buffer = self->buffer;
  buffer += self->stride * index;
  memcpy(buffer, element, self->stride);
  return NO_ERROR;
}

error_t
vector_container_insert_at(
  vector_container_mptr_t vector,
  malunal_size_t          index,
  malunal_iptr_t          element
) {
  if (vector == null)
    return (error_t) {
      .domain = &ERROR_DOMAIN_CONTAINER_T,
      .code   = CONTAINER_ERROR_NULL_CONTAINER
    };

  impl_mptr_t self = (impl_mptr_t)vector;
  if (index > self->count)
    return (error_t) {
      .domain = &ERROR_DOMAIN_CONTAINER_T,
      .code   = CONTAINER_ERROR_OUT_OF_BOUNDS
    };

  error_t result = vector_container_realloc(self);
  if (result.domain != null)
    return result;

  malunal_uint8_t* orig = self->buffer;
  orig += self->stride * index;

  malunal_uint8_t* dest = orig + self->stride;
  memmove(dest, orig, self->stride * self->count - index);
  memcpy(orig, element, self->stride);
  self->count++;
  return NO_ERROR;
}

error_t
vector_container_remove_at(
  vector_container_mptr_t vector,
  malunal_size_t          index
) {
  if (vector == null)
    return (error_t) {
      .domain = &ERROR_DOMAIN_CONTAINER_T,
      .code   = CONTAINER_ERROR_NULL_CONTAINER
    };

  impl_mptr_t self = (impl_mptr_t)vector;
  if (self->count == 0 || index >= self->count)
    return (error_t) {
      .domain = &ERROR_DOMAIN_CONTAINER_T,
      .code   = CONTAINER_ERROR_OUT_OF_BOUNDS
    };

  malunal_uint8_t* dest = self->buffer;
  dest += self->stride * index;

  malunal_uint8_t* orig = dest + self->stride;
  memmove(dest, orig, self->stride * self->count - index);
  self->count--;
  return NO_ERROR;
}

error_t
vector_container_index_of(
  vector_container_iptr_t vector,
  malunal_iptr_t          element,
  malunal_size_t*         outidx
) {
  if (vector == null)
    return (error_t) {
      .domain = &ERROR_DOMAIN_CONTAINER_T,
      .code   = CONTAINER_ERROR_NULL_CONTAINER
    };

  malunal_size_t   index  = 0;
  impl_iptr_t      self   = (impl_iptr_t)vector;
  malunal_uint8_t* buffer = self->buffer;
  while (index < self->count) {
    if (memcmp(buffer, element, self->stride) == 0) {
      *outidx = index;
      return NO_ERROR;
    }

    index  += 1;
    buffer += self->stride;
  }

  *outidx = (malunal_size_t)-1;
  return NO_ERROR;
}