#include <c_CC.h>

/* ------------------------------------------------------------------------------------------------------------------ */
/*  */


// Internal deep structural trace walker that marks vertices within a cluster component
static void c_CC_DFS_Internal(c_CC_t* self, const c_Graph_t* G, c_VertexId_t v, c_VertexId_t current_id) {
    self->marked[v] = C_TRUE;
    self->id[v] = current_id;
    self->size[current_id]++;

    // Access the array-backed adjacency list through the internal graph helper
    c_AdjList_t* list = c_Graph_GetAdjList((c_Graph_t*)G, v);
    if (!list) return;

    // Cache-friendly sequential sweep over flat neighbor array blocks
    for (c_size_t i = 0; i < list->size; i++) {
        c_VertexId_t w = (c_VertexId_t)list->array[i];
        if (!self->marked[w]) {
            c_CC_DFS_Internal(self, G, w, current_id);
        }
    }
}

/* ------------------------------------------------------------------------------------------------------------------ */
/*  */

c_err_t c_CC_Init(c_CC_t* self, const c_Graph_t* G, c_Allocator_t* allocator) {
    if (!self || !G ) {
        return C_ERR_PARAM;
    }

    self->allocator = allocator?*allocator:c_DefaultAllocator;
    self->count = 0;
    self->marked = NULL;
    self->id = NULL;
    self->size = NULL;
    self->V = G->V;

    if (G->V == 0) {
        return C_SUCCESS;
    }

    // Allocate structural metadata array blocks via your custom allocator abstraction layer
    self->marked = (c_bool_t*)c_Allocator_Alloc(&self->allocator, G->V * sizeof(*self->marked));
    self->id = (c_size_t*)c_Allocator_Alloc(&self->allocator, G->V * sizeof(*self->id));
    self->size = (c_size_t*)c_Allocator_Alloc(&self->allocator, G->V * sizeof(*self->size));

    if (!self->marked || !self->id || !self->size) {
        c_CC_Destroy(self);
        return C_ERR_NOMEM;
    }

    // Zero out state maps cleanly
    memset(self->marked, 0, G->V * sizeof(*self->marked));
    memset(self->id, 0, G->V * sizeof(*self->id));
    memset(self->size, 0, G->V * sizeof(*self->size));

    // Run partition sweeps over all available unvisited structural nodes
    for (c_VertexId_t v = 0; v < G->V; v++) {
        if (!self->marked[v]) {
            c_CC_DFS_Internal(self, G, v, self->count);
            self->count++;
        }
    }

    return C_SUCCESS;
}

void c_CC_Destroy(c_CC_t* self) {
    if (!self) return;

    if (self->marked) c_Allocator_Free(&self->allocator, self->marked);
    if (self->id)     c_Allocator_Free(&self->allocator, self->id);
    if (self->size)   c_Allocator_Free(&self->allocator, self->size);

    self->marked = NULL;
    self->id = NULL;
    self->size = NULL;
    self->count = 0;
    self->V = 0;
}

c_bool_t c_CC_Connected(const c_CC_t* self, c_VertexId_t v, c_VertexId_t w) {
    // Parameter boundary filter protection using the internally cached V
    if (!self || v >= self->V || w >= self->V || !self->id) {
        return C_FALSE;
    }
    return self->id[v] == self->id[w];
}

c_size_t c_CC_Id(const c_CC_t* self, c_VertexId_t v) {
    if (!self || v >= self->V || !self->id) {
        return 0; // Return safe default index bounds if lookup fails
    }
    return self->id[v];
}

c_size_t c_CC_Size(const c_CC_t* self, c_VertexId_t v) {
    if (!self || v >= self->V || !self->id || !self->size) {
        return 0;
    }
    return self->size[self->id[v]];
}

c_size_t c_CC_Count(const c_CC_t* self) {
    if (!self) return 0;
    return self->count;
}