#ifndef INCLUDED_C_CPM_H
#define INCLUDED_C_CPM_H

#ifndef INCLUDED_C_EDGEWEIGHTEDDIGRAPH_H
#include <c_EdgeWeightedDigraph.h>
#endif /*INCLUDED_C_EDGEWEIGHTEDDIGRAPH_H*/


#ifndef INCLUDED_C_ACYCLICLP_H
#include <c_AcyclicLP.h>
#endif /*INCLUDED_C_ACYCLICLP_H*/


#ifndef INCLUDED_C_VERTEXIDLIST_H
#include <c_VertexIdList.h>
#endif /*INCLUDED_C_VERTEXIDLIST_H*/


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

typedef struct {
    c_AcyclicLP_t      lp_engine;   /* Inner longest-path engine */
    c_size_t           num_tasks;   /* Raw number of user tasks */
    c_size_t           source_node; /* Virtual source node index */
    c_size_t           sink_node;   /* Virtual sink node index */
    c_size_t           V;           /* Total inner nodes count (2 * num_tasks + 2) */
    c_Allocator_t      allocator;   /* Deep copy of the user-provided allocator */
} c_CPM_t;


/**
 * @brief Initializes and executes the Critical Path Method scheduler.
 * @param task_durations Array of doubles containing durations for each task (size = num_tasks)
 * @param allocator Explicit allocator context used to configure internal tracking state memory
 */
c_err_t c_CPM_Init(c_CPM_t* self, c_size_t num_tasks, const double* task_durations, c_Allocator_t* allocator);

/**
 * @brief Releases internal tracking buffers safely.
 */
void c_CPM_Destroy(c_CPM_t* self);

/**
 * @brief Adds a dependency constraint indicating that 'prereq_task' must finish before 'target_task' can start.
 */
c_err_t c_CPM_AddDependency(c_CPM_t* self, c_EdgeWeightedDigraph_t* working_graph, c_size_t prereq_task, c_size_t target_task);

/**
 * @brief Finalizes the calculation after all dependencies are added.
 */
c_err_t c_CPM_Calculate(c_CPM_t* self, c_EdgeWeightedDigraph_t* working_graph);

/**
 * @brief Returns the minimum total project duration.
 */
C_STATIC_FORCE_INLINE
double c_CPM_GetProjectDuration(c_CPM_t* self) {
    if (!self) return 0.0;
    return c_AcyclicLP_DistTo(&self->lp_engine, self->sink_node);
}

/**
 * @brief Returns the Early Start (ES) time for a given task.
 */
C_STATIC_FORCE_INLINE
double c_CPM_GetEarlyStart(c_CPM_t* self, c_size_t task_id) {
    if (!self || task_id >= self->num_tasks) return 0.0;
    return c_AcyclicLP_DistTo(&self->lp_engine, task_id);
}

/**
 * @brief Extracts the sequence of global edge IDs that form the critical path.
 */
c_err_t c_CPM_GetCriticalPath(c_CPM_t* self, c_VertexIdList_t* out_critical_edges);


#endif /*INCLUDED_C_CPM_H*/